HCMC UNIVERSITY OF TECHNICAL EDUCATION

FACULTY OF FOREIGN LANGUAGES

(For internal use only)

ENGLISH
for
Environmental Technology

VIETNAM NATIONAL UNIVERSITY

HOCHIMINH CITY PUBLISHING HOUSE
HOCHIMINH CITY, 2016
2
ĐẶNG THỊ VÂN ANH
PHAN VŨ BÌNH MINH

English for
ENVIRONMENTAL
TECHNOLOGY

COURSEBOOK

3
TABLE OF CONTENTS

Unit 1: ENVIRONMENTAL SCIENCE AND TECHNOLOGY? .......... 5

Unit 2: THE ATMOSPHERE AND ECOSYSTEM ............................... 13
Unit 3: ENERGY RESOURCES ............................................................. 24
Unit 4: AIR POLLUTION ....................................................................... 35
Unit 5: NOISE POLLUTION .................................................................. 50
Unit 6: WATER POLLUTION .............................................................. 60
Unit 7: WASTEWATER TREATMENT ................................................ 75
Unit 8: SOLID WASTES ........................................................................ 91
Unit 9: SOLID WASTE MANAGEMENT ........................................... 105
Unit 10: SUSTAINABLE DEVELOPMENT ....................................... 117

REFERENCES ..................................................................................... 132

4
 1 ENVIRONMENTAL SCIENCE AND
TECHNOLOGY

Look at the pictures which are all about Environmental science and
discuss the following questions

1. What do you think is environmental science?

2. How do you distinguish the Earth sciences and environmental
science?
3. How do you distinguish environmental science and
environmental technology?
4. How many branches of environmental science do you think of?
What are they?

5
 LISTENING
Task 1: Listen to the lecturer talking about branches of environmental
science and fill in the blanks
1. Various branches of environmental science can be broadly
categorized as ____________ sciences, _________________,
environmental _______________, geosciences and
environmental__________________.
2. ____________sciences study the phenomena of the Earth’s
gaseous outer ____________with an emphasis on its
relationship to other ____________ of the biosphere.
3. ____________analyzes the dynamics of a ____________in a
given area and some aspects of its environment.
4. Environmental ____________focuses on chemical alterations in
the environment, including ____________contamination and
water ____________.
5. Geosciences include disciplines such as geology, physical
____________ and geomorphology.
6. Environmental ____________is a process of appraisal through
which environmental protection and ____________development
are considered.
(Adapted from Lee, 2009)
Task 2: Listen to the lecturer talking about the Earth sciences and
environmental science and fill in the blanks
1. Both the ____________sciences and environmental science deal
with process and change in our natural environment.
2. Environmental science is principally concerned with changes
made by _______ _______ and the subsequent implications for
the ecosphere.
3. The Earth sciences focus on process and change within the
_________ environment without the added factor of _________
intervention.
(Adapted from Lee, 2009)
Task 3: Work with a partner and answer the questions below, using
information from two lectures above

6
 1. How many branches of Environmental science are there? What
are they?
2. What are the similarities and differences between the
Environmental science and the Earth science?
3. What does the atmospheric science deal with?
4. What does ecology deal with?
5. What does environmental chemistry focus on?
6. What do geosciences include?
7. What is environmental assessment?

VOCABULARY
Task 1: What are meanings of the following prefixes? Give at least one
example to each prefix
Prefix Meaning Examples

bio- ……………………………… ………………………………

eco- ……………………………… ………………………………
geo- ………………………………. ………………………………
inter- ……………………………… ………………………………
meteoro- ……………………………… ………………………………

Task 2: Complete each sentence with one of the words or phrases in the
box. Change the form if necessary
plant couple cycle web
greenbelt chain greenhouse deposit

1. Huge coal ___________ have been found in Western Africa.

2. The ___________ was created to stop urban areas spreading into
the countryside
3. They haven’t built any new nuclear power ___________ since
the late 1980s.

7
 4. The oxygen atom ___________ with the oxygen molecule to
form ozone.
5. The series of changes that a living thing goes through from the
beginning of its life until death is called a ___________
6. A food___________ is the flow of energy from one organism to
the next.
7. A food ___________ extends the food chain concept from a
simple pathway to a complex network of interactions.
8. ___________ gas emissions continue to rise as the world
economy grows.
(Adapted from Lee, 2009)
READING
WHAT IS ENVIRONMENTAL TECHNOLOGY?

Environmental technology refers to the field of science concerned with

reducing the human impact on the environment through technological
advances or improvements. Some common applications of environmental
technology deal with reducing energy consumption, limiting man-made
damage to the physical environment, and reducing waste. Areas of
research in the field may involve cleaner energy sources, improved
energy efficiency in transportation and buildings, and methods that
decrease or prevent pollution. This is a broad field that draws on many
sciences, some of which include chemistry, ecology, and biology.
Innovation and advances in environmental technology may have
commercial applications, save money, or be designed to meet
government regulations.

One focus of environmental technology is on finding, using, and

developing clean sources of energy that have a limited impact on the
natural environment. The use of fossil fuels in electricity production
transportation is not only responsible for releasing particulate matter
known as smog, but also for emitting carbon dioxide. According to the
United States government and others, carbon dioxide is a greenhouse gas
and pollutant with the potential to harm human health through climate
change.

Other applications of environmental technology may deal with other

aspects of electricity generation. This may include improving the

8
efficiency, capacity, or availability of newer power sources, such as wind
turbines or solar panels. It may also involve developing relatively newer
sources of energy like wave power or hydrogen fuel cells.

Basic economic factors are often a spur to advances in environmental

technology. This is due in part to the fact that cost-saving solutions are
usually the most efficient. Cost increases of fuels such as gasoline, for
instance, have led to technology aimed at reducing fuel consumption.
Advances in automobile fuel efficiency lower fuel costs while reducing
harmful emissions. Many countries have vehicle efficiency regulations
that were originally developed to conserve energy and keep fuel prices
low but also help combat pollution problems like smog.
Various ways of making buildings more energy efficient have also been a
focus of the science. This could include reducing energy costs related to
lighting, heating and cooling, and water use. So-called sustainable or
green design refers to the planned use of environmental technology in
constructing new buildings that have minimal environmental impact.
Environmental technology also deals with diverse topics related to
human and environmental health, such as waste management, toxicology,
and wildlife protection.
(Schreiber, 2015)
Task 1: Complete each space in the following statements with no more
than four words from the reading text
1. _____________________________ is commonly concerning
cleaner energy sources, energy-efficient transportation and
buildings, and pollution-preventive methods.
2. Environmental technology draws on many sciences including
_____________________________.

3. Environmental technology focuses on improving the

_____________________________ of newer power sources,
such as wind turbines or solar panels and developing relatively
newer sources of energy like wave power or
_____________________________.
4. Environmental technology also focuses on ways of making
buildings _____________________________.
5. Advances in environmental technology are results of seeking
____________________ and reducing ___________________.

9
Task 2: Answer the following questions with a partner

1. What is environmental technology?

2. In what way is environmental technology different from

environmental science?

3. What do applications of environmental technology deal with?

4. What do you think is the most important aspect/ application of

environmental technology? Why?

5. Is there a relationship between enviromental technology and

sustainable development? What is it, if any?

TRANSLATION
Task 1: Translate the following sentences into Vietnamese
1. Environmental science is often equated with the Earth science
disciplines, such as geology and meteorology.
2. The phrase human activity is a common factor that connects all
the disciplines together under the umbrella of Environmental
science.
3. Environmental science exists as a body of knowledge where
specialists work together to address a particular problem that has
been created by human activity.
(Adapted from Lee, 2009)
Task 2: Translate the following sentences into English
1. Sinh quyển là một yếu tố quan trọng của Trái Đất. Nó bao gồm:
vỏ trái đất, nước và khí quyển. Nó chính là ngôi nhà chung cho
tất cả các loài sinh vật.
2. Hệ sinh thái bao gồm tập hợp các quần xã sinh vật và khu vực
sống của sinh vật.
3. Các nhà địa mạo học nghiên cứu về sự hình thành và phát triển
của địa hình và dự đoán các biến đổi của địa hình trong tương
lai thông qua việc kết hợp các quan sát thực tế và thí nghiệm vật
lý.

10
 FURTHER READING
WHAT DO ENVIRONMENTAL SCIENTISTS DO?
Did you you know that in recent years we have had some of the worst
weather since records were first compiled? In 2005, hurricane Katrina
lasid waste to large areas of Louisiana in the southern United States, and
in the same year drought brought misery to thoudands of communities
across the UK. The sheer scale and complexity of current environmental
problems in the 21st century has created a need for scientists and
researchers with a backgroound in environmental science. Environmental
scientists are increasingly playing an important role in helping to manage
and avert changes to our natural environmental nad even to confront
wildful ecocide. But what exactly do environmental scientists do?
Environmental science is a field of study that aims to help human society
better understand and manage the fauna and flora that share the
environment with us. Scientists within this subject focus on the
interactions between human society and the environment, and see how
they can improve things. The science is a combination of geology,
geography, physics, chemistry and biology. By drawing on these fields of
study, the environmental scientist attempts to solve problems by
providing sustainable solutions where man has a negative impact on the
ecology of a region. This role is multi-faceted and may include such tasks
as identifying sources of pollution, assessing the level of flood risk to a
new housing development or perhaps sampling soils from brown field
sites that could be turned over to new uses.
What kind of jobs do you find environmental scientists working in?
Environmental science is a broad subject and you find that people tend to
specialize in one area, although they will often change in their career.
The greatest number of environmental scientists is employed by
government, but more and more posts are appearing in the private sector
because of the need for public companies to adhere to new environmental
rules and regulations.
One common career path is in environmental analysis. In this field,
specialists research the impact on environment of proposed new building
developments. They consider the ways these developments may create
new sources of pollution, propose preventive measures and decide up
ways the project can be completed without damaging local ecosystems.
Another common area for environmental scientists is environmental
compiance. Here they make sure that companies who impact on the
environment – like nulcear plants and oil refineries – are not breaking
11
environmental laws. They help these big polluters reduce inefficient
production methods and cut the amount of hazardous waste they produce.
Environmental scientists can also work as educators in parks and areas
devoted to conservation and ecology, where they teach people about the
ecosphere and how to live in a more eco-friendly manner.
Finally, environmental scientists manage the the use of natural resources
in both the private and public sphere. For example, they may manage
areas of outstanding natural beauty for lanf which belongs to the military,
or they may look after fishing stocks in rivers on a private estate.
What is the future for environmental science? As humans increasingly
affect fragile ecosystems in many places around the world, and as we
become more aware of the interconnectedness of ecosystems, it is clear
that environmental scientists will play an ever-increasing role.
(Lee, 2009, p.17)

12
 2 THE ATMOSPHERE AND
ECOSYSTEM

Look at the pictures, discuss and answer the following questions with
words from the box
1 2

3 4 5

6 7

aerosol altitude atmosphere atom Bromine

Chlorofluorocarbon composition exhaust
molecule Ozone pesticide pollutant
radiation smog ultraviolet
13
 1. What do you think the atmosphere is?
2. What does each picture show?
3. How does/did each item affect the atmosphere?

VOCABULARY
Complete each sentence with a word from the box in page 12. Change
the form if necessary
1. Most modern passenger aeroplanes travel at an _______ of
around 9,000 metres.
2. An _______ consists of electrons, protons and neutrons.
3. _______ radiation is a key factor in the development of skin
cancers.
4. Man-made _______ have contributed to the destruction of the
ozone layer.
5. Nitrous oxide is produced by _______ gases.
6. An _______ is a substance stored in a container under pressure,
normally with a propellant gas, for use as a fine spray.
7. _______ help farmers but sometimes damage the environment.
(Adapted from Lee, 2009)
LISTENING
Task 1: Listen to the lecturer talking about the atmosphere and find the
mistake in each statement below. One statement has only one mistake.
1. The atmosphere is a very simple structure.
2. The atmosphere consists of one layer of gases, particles and
water vapour.
3. With the atmosphere, life would not exist on our planet.
4. It is quite thick, just like the outer skin on an onion.
5. Biological processes play a small role in its past, current and
future composition.
(Adapted from Lee, 2009)

14
Task 2: Listen to part 2 of the lecture and fill in the blanks
1. The gaseous
components of the
atmosphere ________
as we move through
each atmospheric
layer.
2. The lower
atmosphere consists
principally of two
heavy gases:
________ and
________.
3. At about 80 kilometres above the surface of the Earth, the
amount of heavy gases is very much ________.
4. Beyond 150 kilometres, the main gas is oxygen but in fact, its
molecular structure has been broken down into its atomic form
by ________ radiation.
5. The process of breaking down oxygen molecules into its atomic
form is call ________
(Adapted from Lee, 2009)

READING
Although there is no clear boundary between the layers, scientists
divided the atmosphere into four layers according to temperature and
altitude: troposphere,
stratosphere, mesosphere,
and thermosphere. The
temperature drops as we go
up through the troposphere,
but it rises as we move
through the next layer, the
stratosphere. The farther
away from earth, the thinner
the atmosphere gets.

15
 1. TROPOSPHERE
This is the layer of the atmosphere closest to the Earth's surface,
extending up to about 10-15 km above the Earth's surface. It contains
75% of the atmosphere's mass. The troposphere is wider at the equator
than at the poles. Temperature and pressure drops as you go higher up the
troposphere. At 18 kilometres, the division between the troposphere and
the stratosphere, the temperature plunges to minus 60oC. In addition, this
layer is the only one that has any meaningful weather system.
2. STRATOSPHERE
This layer lies directly
above the troposphere and is
about 35 km deep. It extends
from about 15 to 50 km above
the Earth's surface.
The stratosphere is
warmer at the top than the
bottom. The lower portion has a
nearly constant temperature
with height but in the upper
portion the temperature
increases with altitude because of absorption of sunlight by ozone. This
temperature increases with altitude, so it is the opposite of the situation in
the troposphere.
3. MESOSPHERE
Directly above the stratosphere, extending from 50 to 80 km above
the Earth's surface, the mesosphere is a cold layer where the temperature
generally decreases with increasing altitude. The reason is because of an
absence of gases and water vapour to absorb energy from ultraviolet
radiation. Here in the mesosphere, the atmosphere is very rarefied
nevertheless thick enough to slow down meteors hurtling into the
atmosphere, where they burn up, and leave fiery trails in the night sky.

16
 4. THERMOSPHERE
The thermosphere
extends from 80 km above
the Earth's surface to outer
space. The temperature is
hot and may be as high as
thousands of degrees. It is
because in the
thermosphere, few
molecules, which are
mostly broken into ions or
atoms, absorb
extraordinary large amounts of energy from the Sun. These ions are
important because they can reflect radio waves and therefore allow
signals to travel around the globe. These ions are also responsible for the
northern and southern lights. However, the thermosphere would actually
feel very cold to us because of the probability that these few molecules
will hit our skin and transfer enough energy to cause appreciable heat,
which is extremely low.
(Vtaide.com, n.d.)

Task 1: Read the text carefully and answer the questions below
1. Basing on the temperature and altitude, how many layers do
scientists divide the atmosphere into? What are they?
2. Which layers are at the height 20 km?
3. Which layers have the hottest temperature?
4. Why is the mesosphere cold?
5. Which layers contain mostly the atmosphere’s mass? Why?
6. Which layers can help human to transfer the signals? Why?
7. Which layers will absorb the ultraviolet radiaton?
8. In which layers the temperature and pressure will decrease with
increasing altitude?

Task 2: Listen to the statements and decide whether they are True or
False, using information from the text above

17
 True False
1.  
2.  
3.  
4.  
5.  
6.  
(Adapted from Lee, 2009)

THE BIOSPHERE AND ECOSYSTEMS: our planet’s life

support system
Task 3: Scan the text and match the words or phrases on the column A
with their definition on the column B
A B
a. Complex molecules such as sugar or starch
which provide the body with energy
1. Biosphere
b. A system that has no inputs from outside
2. Microorganisms
c. The animal and plant life of a particular region
3. Closed system
d. Dead organic region
4. Carbohydrates
e. Extremely small living things that cannot be
5. Biota
seen by the naked eye
6. Detritus
f. The part of the Earth’s environment where life
exists
One key aspect of Ecology is the study of the Earth’s biological
systems and the interactions that occur within them. The largest system is
the biosphere, which can be described as the intersection of air, water and
land, where life exists. Life only exists because it can draw components
from these three elements. For example, plant can only thrive because
they capture CO2 from the atmosphere which is then converted into food
molecules. The biosphere refers to the planet as a whole. However, when
we look at the interaction of different populations of organisims which
live together in a particular location and the way they interact with the
physical environment, we are describing another biological system which
is known as an ecosystem.

18
 There are two fundamental characteristics of the Earth’s biosphere
we should consider. Firstly, the biosphere is actually a very thin zone of
life. Within this zone, the majority of life occurs in an even narrower
band of tolerance which begins at around 200 metres below the ocean’s
surface and ends at around 6,000 metres above sea level. Beyond this
zone, life becomes sparse. However, every year we are making new
discoveries of life forms in areas which had been considered to be devoid
of life. For example, scientists have found microorganisims, living things
which are too small to be seen withoust a microscope, in deep Antarctic
ice core samples which had been thought to be sterile. Furthermore, a
research focusing on deep sea volcanic vents has shown that numerous
species, including giant tube worms, clams and shrimps, can survive in
extremely high
water temperatures
and pressures.
Another
characteristic of the
biosphere is that it
is a closed system.
In other words, the
biosphere receives
virtually no material
from outside. Apart
from the occasional
meteorite, the only
meaningful input is
sunlight, which is A
vital to almost all
life forms on our planet. For example, the CO2 you exhale today may be
used by a sunflower during photosynthesis next month in southern
France. This CO2 is incorporated into carbohydrates (food molecules)
produced by the sunflower and stored as seed. The seeds are then
consumed by birds and the carbohydrates are broken down again into
their constituent parts during cellular energy production. The cycle is
completed when the CO2 is released back into the atmosphere.
Within each ecosystem, the biota (that is, the flora and fauna of a
particular location) can be classified into three basic types. The first type
are all the green plants we see around us. These are known as producers.
They convert water and CO2 into carbohydrateds and release oxygen as a
waste product. This process is important because, along with minerals,

19
carbohydrates allow plants to produce the organic compounds they need
to survive.
The second type of
organism is known as
the consumer and within
this grouping we find
three basic types. The
first type are called
primary consumers.
They are herbivores that
obtain their energy in the
form of complex organic
B
molecules by feeding on
the producers. Organisms that feed on this group are known as secondary
consumers, and those that feed on secondary consumers are described as
tertiary consumers. Both secondary and tertiary consumers are also
known as carnivores. Therefore, we see that, within an ecosystem, a food
chain exists where there is a transfer of energy starting with the producer
and finishing with the tertiary consumer. To illustrate this, imagine a
snail feeding on a leaf. The snail is caught and consumed by a blackbird,
and the blackbird is then eaten by a cat. Parasites are further type of
consumer. They can be either plants or animals that live in or on another
organism. Often they can be harmful to the “host” but they do not
commonly kill it; rather they coexist with the host.
The final types of organism found in an ecosystem are the
detritivores and the decomposers. Detritivores such as earth worms feed
on detritus or dead plant and animal material. Decomposers such as
bacteria and fungi consume dead organisms and their waste products.
Both play crucial roles in the ecosystem because they break down
organic matter and release nutrients back into the environment.
(Lee, 2009, p. 65)

Task 4: Read the text again and decide whether following statements are
True or False
1. Life only exists because it can draw components from air, water
and food.
2. The biosphere is a closed system, it receives materials from
outside.

20
 3. Four basic types of biota are producers, consumers, detritivores
and decomposers.
4. Oak trees, sunflowers, grass are examples of producers.
5. A cat in this text is a representative of tertiary consumers.
6. The cycle in figure A is completed when the hawk died and it is
decomposed by bacteria and fungi.
7. In an biosphere cycle, waste products of this organism will be
used by others.
8. Because parasites do not kill the host, they are not considered
consumers.

TRANSLATION
Task 1: Translate the following sentences into Vietnamese
1. CFCs in aerosols and refrigerators were initially replaced with
hydrochlorofluorocarbons or HCFCs, which are now thought to
be potent greenhouse gases.
2. The three major influences on the development of the
atmosphere have been solar radiation, volcanic activity and
biological processes.
3. It is clear that the biosphere is a closed systems which has only
one significant input, namely solar energy. Components such as
water, atmospheric gases and minerals are constantly recycled
within the biosphere rather than being added to from an outside
source.
4. At the initial stage, the CO2 is exhaled by a primary, secondary
or tertiary consumer. The CO2 may then be captured by a green
plant to be used when it produces food molecules during
photosynthesis.
5. These food molecules are then stored as seeds. The process is
finished when the seeds are eaten by a primary consumer and
the CO2 is released back into the environment as a waste product
of cellular energy production.

21
Task 2: Translate the following sentences into English
1. Vào thời nguyên thủy, Trái Đất được bao quanh bởi một tầng
khí quyển mỏng, chủ yếu bao gồm khí Hidro và Hêli.
2. Sự hoạt động của núi lửa cũng góp phần tạo ra các loại khí cần
thiết để hình thành khí quyển.
3. Trong thực tế, cú và các loài chim nhỏ nên được xếp vào sinh
vật tiêu thụ bậc 3 vì thức ăn của chúng thường là các sinh vật
tiêu thụ bậc 2.

FURTHER READING
OZONE DEPLETION
Ozone layer is important because it acts as a shield protecting
animal and plant life from harmful ultraviolet radiation. There are
actually two ozone layers: one of them occurs in the stratosphere, the
other in the troposphere. The
one in the stratosphere is by
far the bigger of the two and
is formed naturally. The
ozone layer in the
troposphere is anthropogenic,
or produced by human
activity.
What are the chemical
processes that create ozone?
To start with, UV radiation
splits an oxygen molecule into oxygen atoms. Then, one of these atoms
combines with another oxygen molecule to form an ozone molecule (O3).
Actually, ozone is constantly being formed and destroyed; a natural
balance between the production and destruction of these molecules seem
to exist.
However, at the beginning of the 20th century, human industrial
activity has upset this balance by producing Chlorine-based chemicals
called Chlorofluorocarbons (CFCs). These compounds have accelerated
the destruction of the ozone layer, especially in the Polar Regions.
Actually, a reduction in the ozone layer would lead to DNA damage and

22
an increase in skin cancers and cataracts. It would reduce photosynthesis,
and even disrupt the way insects navigate and see.
In 1987, over 30 countries signed the Montreal Protocol in which
the signatories agreed to cut CFC use by 50% by the year 2000. This
protocol was further extended two years later, when over 80 countries
agreed to stop using CFCs completely by the year 2000. Also, in 1991, a
fund was set up to help developing countries change over to non-CFC
technologies and it has met with some success. Hopefully, new
technologies will continue to provide safer alternatives to CFCs, HCFCs
and other gases that harm the atmosphere. However, there is still some
use of ozone-depleting gases, such as methyl bromide in some pesticides,
and some countries who haven’t signed the Montreal Protocol are still
using CFCs. So, it is estimated that it will take several lifetimes for the
ozone layer to recover.
(Lee, 2009)

23
 3 ENERGY RESOURCES

Look at the pictures, discuss and answer the following questions

1 2

3 4

5 6

24
 7

(Lee, 2009)
1. Name the types of energy production.
2. Which types are most commonly used today?
3. Will this situation stay the same in the future?

VOCABULARY
Read the text carefully and fill in the blanks with given words in the box

fossil fuels Confront greenhouse effect

geosciences Nuclear geothermal
acid rain Gravitational photosynthesis

Faculty: Environmental Science

Lecture: Introduction to energy resources
Without energy, it would be very difficult for modern society to
function and for modern industry to operate its machines. There are four
basic kinds of energy we can use:
1. The Earth’s internal heat – this is often exploited as
(1)___________ power.
2. Solar activity – this provides energy for the wind and water
cycle. It is converted into biomass via (2)____________and it then
generate heat and light.
3. The pull of the Moon and Sun – the (3)______________ effect
causes tides.

25
 4. (4) __________ power – energy released from atoms.
All types of energy consumption have an effect on our natural
environment. For example, there is a direct linkage between the burning
of (5)_____________ and increasing global temperatures. In addition,
sulphur dioxide, which is a by-product of burning coal, contributes to
(6)____________ which damages our natural surrounding. Therefore, it
has become important for countries around the world to make hard
decisions, and to develop less harmful types of energy production to
(7)____________the growing environmental problems which we face.
(Adapted from Lee, 2009)
LISTENING
Task 1: Listen to the lecture and put the information into the right order
1. This unexpected temperature in the water will _______
change the local ecosystem, which is called thermal
pollution.
_______
2. Oil spills have bad effects on our marine and
coastal environments.
3. Coal and oil-fired power stations need large _______
amounts of water for cooling, which is then released back
into the body of water at a high temperature.
_______
4. Coal and oil has bad repercussion on the
environment.
5. Burning fossil fuels release greenhouse gases into _______
the atmosphere.

Task 2: Discuss in group the following questions then listen to the

lecturer to find the correct answers
1. What are the main renewable types?
2. Is wind power used recently only? Why?
3. What is the main function of wind power today?
4. What does the amount of generated power depend on?
5. What are environmental problems caused by power generation
from the wind?

26
Task 3: Listen to the lecturer talking about wind energy and fill in the
blanks
Of course, wind power has been used for centuries, mainly for
(1)_________ and (2)_________. But these days, it’s increasingly used
to (3)___________. In slide 4 you can see how this process works.
Unfortunately, an average annual (4)________ of over 5 cubic
metres per second is desirable if a wind farm is to be (5)________. So, it
follows that the sites chosen to locate wind farms have a good
(6)________. Actually, even when wind farms are located in
(7)__________, it has been estimated that they only operate for a third of
the time.
On the other hand, it’s clear that the more wind farms we build, the
less we will be dependent on (8)_______. What I mean is, although some
people say wind farms are not (9)_______, basically they’re still a less
polluting option than (10) ___________.
(Adapted from Lee, 2009, p.41)
READING
Task 1: Categorize the following ideas into advantages (A) and
disadvantages (D) of solar power. Write the letter on the space given
before each idea
1. ______ It works well in remote areas where there isn’t easy
access to the National Grid.
2. ______ In many countries there is too much ‘dark time’,
especially in winter, when most power would be needed for
lighting and heating.
3. ______ It works in cold and cloudy conditions too. Solar power
has been used in both the Arctic and Antarctic.
4. ______ It works well in poorer, hot countries as it costs very
little to run. A small PV cell can power a whole house.
5. ______ It is expensive to install – the materials are costly.
6. ______ Storage and transportation of the electricity to where it
is needed is difficult.
7. ______ The sun isn’t going to run out – well not for another
5000 million years! So it is a sustainable form of energy
(provided the materials required to make the equipment don’t
run out).
27
 8. ______ No harmful gases are released once the equipment is
installed.
9. ______ Large scale solar farms take up land which could be
used for growing crops for food; and they are considered ugly
by some people.

SOLAR POWER
We live on a solar-powered planet; the ultimate source of energy
on this planet is the sun; the feel of the heat of the sun on your skin is
solar energy! It provides energy for plants to grow, which in turn provide
food (which is energy) for animals. The sun provides us with heat and
light every day, which we can use to make electricity. There are three
types of solar power:
1. PVs
You’ll have seen solar powered
calculators, watches and garden patio
lights? The same technology can be
used to provide electricity to whole
buildings - just on a larger scale. This
type of solar power comes from
photovoltaic cells or PVs. Lots of PVs
together make up solar panels on the
roofs of houses and other buildings.
They work by using the sunlight to split
electrons from atoms. The energy
released during this process is converted
into electricity.
2. Thermal collectors
These create hot water rather than electricity. They are made up of
a series of tubes sandwiched between sheets of glass (with a black
backing to absorb the sun’s heat) on the roofs of houses. Water in the
tubes heats up in the sunlight and starts to flow into a hot water tank.
Bingo - the house has hot water! Systems like this can reduce the need
for other energy sources by two thirds.
3. Passive solar energy
This is when a building is designed and built to make the most of
the natural position of the sun. So in the Northern Hemisphere (e.g. UK,

28
USA, China) houses can be built facing south (where the sun shines most
of the day) with big windows on that side to act like a greenhouse and
warm the house without having to put the heating (or lights) on as much.
This can halve heating bills!
Concentrated Solar Power (CSP)
This is a
new system
where giant
movable mirrors
called heliostats
are used to
reflect the sun’s
rays and
concentrate the
heat onto a
vessel containing
water or another
liquid, similar to
oil. This creates
steam to turn turbines and generate electricity. The best place for this
technology to be used is in the desert.
 Within 6 hours deserts receive more energy from the sun than
the whole of the world’s population uses in a year.
 Every year 1 square km of desert receives an amount of solar
energy equivalent to 1.5 million barrels of oil. This means that only 1%
of the world’s deserts would need to be used to meet the world’s current
energy needs.
 According to DESERTEC, 90% of people live within 2,700 km
of a desert and could be supplied with solar electricity from there.
Developing countries such as China and India could avoid the use of
fossil fuels in their development by moving straight over to this
technology.
 It is possible to store the solar heat in melted salts so electricity
can still be generated when it is not sunny.
 Another advantage of CSP is that sea water could be desalinated
to provide fresh drinking water in arid regions using the waste heat from
CSP plants. It could also be used to water plants for food which could be
grown in the shaded areas underneath the mirrors.

29
 There are 4 main systems of Concentrated Solar Power
Technology:
1. The Solar Tower is a new
system currently being tested in
Spain. It could provide enough
energy for 600,000 people. It’s a
giant concrete tower, 40 storeys
high surrounded by 624 heliostats
at the base all focused on the top of
the tower where it can heat up
water pipes, to create steam which
is blasted through turbines.
2. Trough Systems use curved
mirrors to focus light onto a tube containing oil or a similar fluid that
carries the heat to a place where it can be used to create steam and
generate electricity.
3. Fresnel Mirrors work in the same way as the trough system but
instead these are long, flat mirrors placed at different angles. Sometimes
they are focused onto photovoltaic solar panels.
4. Dishes of mirrors track the sun (a bit like a giant television
satellite dish). They each have a Stirling engine at their focal point which
works by using an external heat source (unlike a standard internal-
combustion engine which may run off petrol or diesel) to convert the heat
energy into electricity.
(Sims, n.d.)
See the website www.trec-uk.org.uk for further information.

Task 2: Answer the following questions

1. What are solar panels on the roofs of houses used for?
2. Which type of the solar power is the cheapest? Which type is the
most efficient?
3. Who are beneficiaries of the CSP technology?
4. What are advantages of the CSP technologies?
5. What are main differences between four main systems of CSP
technology?

30
Task 3: Discuss the following questions
1. Which type of the solar energy is the most popularly used in
your country?
2. Which direction do you think houses in the Southern
Hemisphere (e.g. Australia, New Zealand and Argentina) should
face?
3. Which do you think is the most advantageous characteristic of
solar power?
4. Although advantages outnumber drawbacks, why have solar
energy not totally replaced traditional energy like thermal power
or hydroelectric energy?

VOCABULARY
Task 1: Explain the bolded words/ phrases in the following sentences
taken from the reading text
1. They are made up of a series of tubes sandwiched between
sheets of glass on the roofs of houses.
2. This is a new system where giant movable mirrors called
heliostats are used to reflect the sun’s rays and concentrate the
heat onto a vessel containing water or another liquid, similar to
oil.
3. Another advantage of CSP is that sea water could be
desalinated to provide fresh drinking water in arid regions
using the waste heat from CSP plants.
4. It’s a giant concrete tower, 40 storeys high surrounded by 624
heliostats at the base all focused on the top of the tower where it
can heat up water pipes, to create steam which is blasted
through turbines.
5. Dishes of mirrors track the sun (a bit like a giant television
satellite dish).
Task 2: Complete the sentences with appropriate words/ phrases from
the box
interfere cooker power mission
house trundle satellites robots

31
 On a big scale, solar technologies are used to __(1)__whole
settlements, space craft and satellites.Here are some examples:
 The largest Solar PV ‘farm’ in the world is about to be
completed near Moura in Portugal. Each of the 2520 solar
panels is the size of a__(2)__! It is expected to provide power
for 30,000 homes.
 __(3)___and the Hubble Space Telescope are covered in solar
PV cells which power the computers, cameras and radio systems
on board. Up in space there are no clouds or seasons to
__(4)___with the sunshine!
 The __(5)___sent to Mars have solar cells too. ‘Spirit’ and
‘Opportunity’ __(6)__ along using solar power so they can take
amazing photographs and send them back to Earth. The two
robots were only meant to last for a 90 day __(7)___– they have
now been up there more than 5 years!
 The World’s largest solar __(8)___is in Rajasthan, India. It can
produce food for 10,000 people!

TRANSLATION
Task 1: Translate the following paragraphs into Vietnamese
1. The oil was made under the seas and oceans from the
decomposition of microscopic life called phytoplankton. With
layer upon layer of decaying phytoplankton create high
temperatures and pressure. The organic matter is transformed
into complex hydrocarbons, which are the main compound that
creates oils.
2. Wave and tidal energy facilities generate electricity without
producing any pollutant emissions or greenhouse gases. Wave
and tidal facilities also have little or no visual impact, as they are
either submerged or do not rise very far above the waterline.
3. In the geothermal plants, the geothermal fluids contain elevated
levels of arsenic, mercury, lithium and boron because of the
underground contact between hot fluids and rocks. Its waste is
released into rivers or lakes instead of being injected into the
geothermal field. These pollutants can damage aquatic life and
make the water unsafe for drinking or irrigation.
32
Task 2: Translate the following paragraphs into English
1. Một tác động nghiêm trọng của ngành công nghiệp năng lượng
địa nhiệt đến môi trường là ô nhiễm thạch tín. Mức độ thạch tín
trong sông Waikato hầu như luôn luôn vượt quá tiêu chuẩn cho
nước uống của Tổ chức Y tế Thế giới.
2. Việc đốt sinh khối để sản xuất điện gây ảnh hưởng đến chất
lượng không khí. Mức độ khí thải ở các nhà máy điện sinh khối
thường là khác nhau, tùy thuộc vào nguyên liệu, công nghệ đốt
và cách thức kiểm soát ô nhiễm. Tuy nhiên, các chất ô nhiễm
phổ biến nhất thường bao gồm các khí NOx, SO2, CO và một số
khí khác.

FURTHER READING

Water power goes back 2500 years when water wheels where first
used to power mills. The rotating wheel would be attached to a
mechanism which could grind wheat into flour, or weave wool. Water
mills were very common until electricity became easily available in the
19th century.
Modern water power is called hydro-electric power (HEP) and water
is used to generate electricity.
There are many different ways to do this:

Dams, Reservoirs and Rivers

The most common form of HEP is when a dam is built across a river
and a huge lake or reservoir forms behind the dam. Water is then let out
through the dam where there are turbines that spin as the water flows
through them. The turbines are connected to generators and these
produce electricity. This power is then transported along cables and
distributed to homes, offices and factories. 15% of the world’s renewable
energy is produced like this – more than any other renewable energy
source.

33
Wave Power
Waves are formed when the wind blows across the surface of the
sea. There is a lot of power in waves and this can be used to make
electricity. There are different types of wave electricity generators.
Oscillating Water Columns (OWCs) are situated at the shore and the
waves crash into them, sending water up a concrete column, forcing
air through a turbine at the top of the column.
‘Nodding Ducks’ float up and down on the surface of the sea and
their movement causes a shaft to move, which is attached to a turbine
which turns and creates electricity.
The Sea Snake – or Pelamis Wave Energy Machine. This is a semi-
submerged device which has many hinged joints which move with the
water. This movement triggers hydraulic motors and these are
attached to generators which create electricity. It is 120m long and
3.5m wide. If lots were moored together it could create a ‘wave farm’.

34
 4 AIR POLLUTION

Write the empirical formula next to each chemical in the list

Ozone ……………………… Nitric acid ………………………
Carbon ……………………… Benzene ………………………
monoxide
Nitrogen ……………………… Hydrogen ………………………
dioxide sulfide
Oxygen ……………………… Sulfuric ………………………
acid
Sulfur ……………………… Methane ………………………
dioxide
Discuss the following questions with a partner
1. What are the causes and effects of air pollution?
2. What can be done to reduce air pollution in big cities?

35
 READING
Air pollution occurs when the concentrations of certain substances
become high enough to cause the atmospheric environment to become
toxic. Air pollutants can be gaseous, liquid or solid in form, and can
come from natural as well as human sources. Some examples of natural
sources of air pollution include forest fires, pollen, volcanic emissions,
and dust. Human sources of air pollutants include emissions from
industry, agriculture, forestry, transportation, power generation and space
heating.
Air pollution can threaten the health of human beings, trees, lakes,
crops and animals. Abundant amounts of air pollution changes natural
atmospheric processes, causing acid rains, ozone hole and enhancing
greenhouse effect. Additionally, it causes economic losses.
Pollutants are classified either
as primary pollutants - those that
enter the atmosphere directly from
various sources, or as secondary
pollutants - those that are formed
when primary pollutants react with
each other or with other compounds
present in the atmosphere.
Industrial or gray smog is
considered the most serious type of
air pollution. Smoke and oxides of
that are released by burning coal and
oil containing minor amounts of
sulfur is the cause. The smoke gives
the air a gray color. Industrial smog
has been known to cause air
pollution disasters. One of the worst occurred in London in December of
1952. Five days of stagnant air brought about high-pressure systems
caused between 3,500 and 4,000 deaths.
Another main cause of air pollution is exhaust fumes from cars and
other vehicles that run on gasoline or diesel. Until a few years ago, lead
was added to most gasolines to make car engines run better. The lead
passes through the engine and out of the exhaust system into the air. Lead
is a highly toxic metal and can cause nervous system damage and
digestive problems.

36
 Road traffic
emissions, particularly
from diesel vehicles
are a major source of
particulate matters
and nitrogen oxides.
PM10 particles (the
fraction of particulate
in air of very small
size (<10 µm) are of
major current concern,
as they are small enough to penetrate deep into the lungs and so
potentially pose significant health risks. Particles are often classed as
either primary or secondary pollutants.
Sulfur and nitrogen oxides (primary pollutants) from power plants,
industry, cars and other sources cause rain, snow and fog to become
acidic. The most serious damage caused by acid rain today is
acidification of water lakes and rivers. In some cases they become so
acidic that they can no longer support fish and their food chains. Forest
health can also be affected from this in areas where the soils are being
acidified.
Ozone depletion is another result of air pollution. The ozone layer
in the stratosphere protects the earth from harmful ultraviolet radiation
from the sun. Release of chlorofluorocarbons (CFC's) from aerosol
sprays, polystyrene containers, refrigerator coolant and air conditioning
units removes some of the ozone, causing "holes"; to open up in this
layer and allowing the radiation to reach the Earth.
Ozone in the in
the upper level occurs
naturally and protects
life on earth but ozone
at ground level is a
noxious pollutant. It is
the major component
of photochemical smog
(also known as brown
smog) and presents the
most intractable urban
air quality problem.
Ozone is not emitted directly. It is secondary pollutant formed in the

37
atmosphere through a complex set of chemical reactions involving
hydrocarbons, oxides of nitrogen and sunlight. The rate at which the
reactions proceed is related to both temperature and intensity of the
sunlight.
The greenhouse effect, also referred to as global warming, is
generally believed to come from the build-up of carbon dioxide (CO2)
gas in the atmosphere. Carbon dioxide is produced when fuels are
burned. Plants convert carbon dioxide back to oxygen but the release of
carbon dioxide from human activities is higher than the world's plants
can process. The situation is made worse since many of the earth's forests
are being removed and plant life is being damaged by acid rain.
Finally, air pollution can also occur indoors. Common indoor air
pollutants include carbon monoxide and nitrogen dioxide from faulty gas
heaters and cookers, carbon monoxide and benzene from cigarette
smoke, and volatile organic compounds (VOCs) from synthetic
furnishings, vinyl flooring and paints. In addition, there are biological
pollutants such as dust mites and mould.
Adequate ventilation is a key to controlling exposure to indoor air
pollution. Home and work environments should be monitored for
adequate airflow and proper exhaust systems installed.
Air pollution generates various economic losses but their detailed
estimation is extremely difficult. They may be divided into four groups:
expenses for air quality protection; expenses generated by the worse
health condition of the society; losses of raw materials which become air
pollution; losses caused by the increased corrosion of machines,
buildings, and damage of historical buildings and monuments.
The problem of air pollution is worldwide and transcends national
boundaries. Though air pollution is still a serious problem, in many
countries in the world, steps are being taken to stop the damage to our
environment from air pollution. Many electric power plants, factories and
facilities that burn wastes are equipped with devices called scrubbers.
Scrubbers remove sulfur dioxide and other pollutants before the wastes
are released into the air. Also, today's cars are designed to create less
pollution. Many are equipped with anti-pollution devices called catalytic
converters, which reduce the amount of pollution from automobile
engines.
(Bayanova, 2014)

38
Task 1: Decide whether the following statements are TRUE or FALSE
1. The most serious effect that air pollution causes is economic
losses.
2. Primary air pollutants are emitted directly into the air from
sources such as industries, cars, etc.
3. Human sources of air pollutants are more diverse than natural
sources.
4. Industrial smog is considered the most serious type of air
pollution because it gives the air a gray color.
5. Toxic lead in gasoline pollutes the air when vehicles burn
gasoline and release exhaust fumes into the air.
6. The acidification of water bodies is the most serious damage
that acid rain brings about because it endangers the aquatic
ecosystem.
7. Ozone holes allow ultraviolet light from the sun to reach the
earth.
8. The greenhouse effect is the result of heat and carbon dioxide
released from greenhouses for growing plants.
9. Indoor air pollution can be controlled by installing adequate
ventilation system in houses and working places.
10. Many cars are now fitted with catalytic converters to reduce
the damage that exhaust fumes cause to the environment.
Task 2: Discuss the following questions in groups
1. According to the text, what are the effects of air pollution? In
your opinion, which effect is the most harmful? Explain your
answer.
2. What are the causes and effects of “The Big Smoke” in London
in 1952?
3. Why is lead added to gasoline? Why isn’t it good for human
health?
4. What chemicals can be found in acid rain? Describe the process
of forming acid rain.
5. Is ozone at ground level primary or secondary pollutant? How is
it formed?

39
 6. What causes holes in the ozone layer? Describe the process of
ozone depletion.
7. What are greenhouse gases? What can be done to reduce
greenhouse effects?

VOCABULARY
Task 1: Which of the words in bold in the text has the following
meaning?
a. harmful or poisonous
b. not moving or flowing and often smelling bad
c. the gradual destruction of metal by the effect of water,
chemicals, etc.
d. go beyond the usual limits of something
e. difficult to deal with or solve
f. that changes easily into a gas
g. more than enough, plentiful
h. the process of becoming acid or being converted into an acid
i. the process of letting fresh air into a room, building, etc.
j. a complex mixture of extremely small particles and liquid
droplets which is made up of a number of components, including acids
(such as nitrates and sulfates), organic chemicals, metals and soil or dust
particles
k. enter something and pass or spread through it
l. the reduction in the amount of something that is present or
available

Task 2: Complete the following passage with the words in the box
deposit poisonous acidic aggravate exposure
infiltrates pollutant continual organism aquatic

What are the effects of air pollution?

Acidification

40
 Chemical reactions involving air pollutants can create acidic
compounds which can cause harm to vegetation and buildings.
Sometimes, when an air (1)________________, such as sulfuric acid
combines with the water droplets that make up clouds, the water droplets
become (2)_____________, forming acid rain. When acid rain falls over
an area, it can kill trees and harm animals, fish and other wildlife.

Acid rain destroys the leaves of plants. When acid rain

(3)______________into soils, it changes the chemistry of the soil making
it unfit for many living things that rely on soil as a habitat or for
nutrition. Acid rain also changes the chemistry of the lakes and streams
that the rainwater flows into, harming fish and other
(4)_______________life.
Eutrophication
Rain can carry and (5)_____________the Nitrogen in some
pollutants on rivers and soils. This will adversely affect the nutrients in
the soil and water bodies. This can result in algae growth in lakes and
water bodies, make conditions for other living (6)_______________
harmful.
Ground-level ozone
Chemical reactions involving air pollutants create a
(7)_____________gas ozone (O3). Gas Ozone can affect people’s health
and can damage vegetation types and some animal life too.
Particulate matter

41
 Air pollutants can be in the form of particulate matter which can be
very harmful to our health. The level of effect usually depends on the
length of time of (8)____________, as well the kind and concentration of
chemicals and particles exposed to. Short-term effects include irritation
to the eyes, nose and throat, and upper respiratory infections such as
bronchitis and pneumonia. Others include headaches, nausea and allergic
reactions. Short-term air pollution can (9)____________the medical
conditions of individuals with asthma and emphysema. Long-term health
effects can include chronic respiratory disease, lung cancer, heart disease,
and even damage to the brain, nerves, liver, or kidneys. (10)
_____________exposure to air pollution affects the lungs of growing
children and may aggravate or complicate medical conditions in the
elderly.
(eschooltoday, n.d.)

TRANSLATION
Task 1: Translate the following paragraphs into Vietnamese
1. Paint and solvents give off volatile organic compounds (VOCs)
as they dry. Lead paint can degenerate into dust and be inhaled.
2. Intentional air pollution is introduced with the use of air
fresheners, incense and other scented items. Controlled wood
fires in stoves and fireplaces can add significant amounts of
smoke particulates into the air, inside and outside.
3. Carbon monoxide (CO) poisoning is a quick and silent killer,
often caused by faulty vents and chimneys or by the burning of
charcoal indoors. Chronic carbon monoxide poisoning can result
even from poorly adjusted pilot lights.
4. Smoke inhalation is a common cause of death in victims of
house fires. Traps are built into all domestic plumbing to keep
deadly sewer gas, hydrogen sulfide, out of interiors.
5. Between 1970 and 1993 the total amount of lead added to
gasoline worldwide dropped 73%, from more than 375,000 tons
to less than 100,000 tons. At present, lead additives for gasoline
appear principally to be produced by a single company -
Associated Octel, Ltd. The original producer - Ethyl
Corporation - no longer manufactures tetraethyl lead but rather
purchases it from Octel. Much smaller amounts are
independently produced in Germany and Russia.
42
Task 2: Translate the following sentences into English
1. Các tổ chức bảo vệ môi trường quốc tế cảnh báo rằng hoạt động
của loài người sẽ khiến hệ sinh thái tự nhiên trên Trái Đất bị
xuống cấp với tốc độ cao chưa từng có trong lịch sử.
2. Tổ chức Nông lương Liên Hiệp Quốc (FAO) thông báo: “Nếu
quy đổi ra khí CO2, ngành chăn nuôi tạo ra lượng khí gây hiệu
ứng nhà kính nhiều hơn tất cả xe ô tô cộng lại.”
3. Sở Tài nguyên và Môi trường TP. HCM cho biết: Đến hết tháng
11-2006, gần 580 cơ sở gây ô nhiễm buộc phải di dời ra khu vực
ngoại thành và thực hiện các biện pháp khắc phục ô nhiễm môi
trường.

FURTHER READING
Read and use tables/ charts to summarize the following article
about acid rain

What is acid rain?

Acid rain is a result of air pollution. When any type of fuel is burnt,
lots of different chemicals are produced. The smoke that comes from a
fire or the fumes that come out of a car exhaust don't just contain the
sooty grey particles that you can see - they also contains lots of invisible
gases that can be even more harmful to our environment.
43
 Power stations, factories and cars all burn fuels and therefore they
all produce polluting gases. Some of these gases (especially nitrogen
oxides and sulphur dioxide) react with the tiny droplets of water in
clouds to form sulphuric and nitric acids. The rain from these clouds then
falls as very weak acid - which is why it is known as "acid rain". The
release of sulphur dioxide can also occur naturally when a volcano
erupts.
Acid rain was considered a major problem in the 1980s and while
steps to reduce sulphur emissions have been succesful we are still feeling
the effects today, and there is still work to be done.
Where is it coming from?
Air pollution was once seen as a local issue but it was in southern
Scandinavia in the late 1950s that the problems of acid rain were first
observed and it was then that people began to realise that the origins of
this pollution were far away in Britain and Northern Europe. One early
answer to industrial air pollution was to build very tall chimneys.
Unfortunately, all this does is push the polluting gases up into the clouds
allowing emissions to float away on the wind. The wind carries the
pollution many hundreds of miles away where it eventually falls as acid
rain. In this way Britain has contributed at least 16% of the acid rain that
has fallen in Norway. In fact, over ninety percent of Norway's acid
pollution comes from countries other than itself. In 1994, Germany, UK,
Poland and Spain produced over a million tons of sulphur emissions
each. Governments have since admitted that acid rain is a serious
environmental problem and many countries have taken steps to reduce
the amount of sulphur and nitrogen emissions but they are still a problem.
Ships are major contributors to sulphur emissions as the sulphur
content of their heavy fuel oil is very high (5% compared to the EU
maximum allowed in car fuels of 0.001%). The shipping industry is
taking steps to reduce emissions as estimates predict that if nothing is
done soon then the sulphur emissions of the industry would exceed all
those from land-based sources by 2020.
The effects of acid rain
Acid rain can be carried great distances in the atmosphere, not just
between countries but also from continent to continent. The acid can also
take the form of snow, mists and dry dusts. The dry dust can cause
respiratory illnesses in animals and humans such as asthma. The rain
sometimes falls many miles from the source of pollution but wherever it

44
falls it can have a serious effect on soil, trees, buildings and water. In the
1970s, the effects of acid rain were at their worst.
Forests all over the world were dying and in Scandinavia the fish
were dying; lakes looked crystal clear but contained no living creatures
or plant life. Many of Britain's freshwater fish were threatened; their
eggs were damaged and deformed fish were hatched. This in turn
affected fish-eating birds and animals. Animals belong to a food chain
and often if one link in a food chain is taken away it can have devastating
effects.

Forests
It is thought that acid
rain causes trees to grow
slower or even to die but
scientists have found that the
same amount of acid rain
seems to have more effects in
some areas than it does in
others. As acid rain falls on a
forest it trickles through the
leaves of the trees and runs down into the soil below. Some of it finds
its way into streams and then into rivers and lakes. Some types of soil
can help to neutralise the acid - they have what is called a "buffering
capacity". Other soils are already slightly acidic so these are particularly
susceptible to the effects of acid rain.
Acid rain can effect trees in several different ways, it may:
• dissolve and wash away the nutrients and minerals in the
soilwhich help the trees to grow such as potassium, calcium and
magnesium.
• cause the release of harmful substances such as aluminium into
the soil and waterways which further affects wildlife.
• wear away the waxy protective coating of leaves, damaging
themand preventing them from being able to photosynthesise
properly.
A combination of these effects weakens the trees which means
that they can be easily attacked by diseases and insects or injured by
bad weather. It is not just trees that are affected by acid rain, other

45
plants may also suffer.
Lakes and rivers
It is in aquatic habitats that the effects of acid rain are most
obvious. Acid rain runs off the land and ends up in streams, lakes and
marshes - the rain also falls directly on these areas.
As the acidity of a lake increases, the water becomes clearer and the
numbers of fish and other water animals decline. Some species of plant
and animal are better able to survive in acidic water than others.
Freshwater shrimps, snails, mussels are the most quickly affected by
acidification followed by fish such as minnows, salmon and roach. The
roe and fry (eggs and young) of the fish are the worst affected as the
acidity of the water can prevent eggs from hatching properly, can cause
deformity in young fish which also struggle to take in oxygen.
The acidity of the water does not just affect species directly, it
also causes toxic substances such as aluminium to be released into the
water from the soil, harming fish and other aquatic animals.
Lakes, rivers and marshes each have their own fragile ecosystem
with many different species of plants and animals all depending on each
other to survive. If a species of fish disappears, the animals which feed
on it will gradually disappear too. If the extinct fish used to feed on a
particular species of large insect, that
insect population will start to grow,
which in turn will affect the smaller
insects or plankton on which the larger
insect feeds.
Buildings
Every type of material will become
eroded sooner or later by the effects of
the climate. Water, wind, ice and snow all
help in the erosion process but
unfortunately, acid rain can help to make
this natural process even quicker. Statues,
buildings, vehicles, pipes and cables can
all suffer. The worst affected are things
made from limestone or sandstone as these types of rock are particularly
susceptible and can be affected by air pollution in gaseous form as well
as by acid rain.
What has been done?

46
 1970 was the worst year for air pollution in the UK with over 6
million tonnes of sulphur dioxide being released. In 1973 and 1979
there was a noticeable jump in emissions due to cold winters and a
greater need for heating in our homes, shops and work places. By the
year 2000 this was reduced to just over 1 million tonnes and by 2010 it
was hoped it would only be 0.6 million tonnes.
Introduced across Europe on 1 January 2008, the Large
Combustion Plant Directive (LCPD) aims at reducing sulphur emissions
by giving coal fired plants two options. They can either agree to a very
limited running programme and close down by 2015, or install the
equipment needed to remove sulphur from plant emissions.
The 1999 Gothenburg Protocol set limits on emissions and came
into force in 2010. Unfortunately, international agreements failed to
include shipping which uses sulphur - rich fuels that are now banned on
land, so emissions from the North sea could still reach countries such as
Norway. However, in July 2011 the European Commission proposed to
reduce sulphur emissions from the fast-growing maritime and shipping
industry by 90% by limiting the legal sulphur content allowed in fuels
in certain areas such as the Channel and Baltic Sea.
Whilst many countries have reduced their emissions, an upsurge
in industrialisation and reliance on fossil fuels in countries such as
China could lead to a further increase in sulphur dioxide emissions.
What about nitrogen?
Although the amount of sulphur dioxide that is being released has
been cut considerably, more needs to be done about nitrogen oxide from
motor vehicles and agricultural fertilizers. When nitrogen oxide mixes
with rain it forms nitric acid. Acid rain drains important plant nutrients
from the soil and releases minerals such as aluminium into water
courses.
Too much nitrogen in our waterways can lead to eutrophication.
This is when algal blooms or just a few dominant plant species take
over and block all the light for underwater plants. When the algae dies
and starts to decompose, tiny decomposing organisms use up all the
oxygen, leaving none for other aquatic creatures.
Restoring the damage
Lakes and rivers can have powdered limestone added to them to
neutralise the water - this is called "liming". Liming, however, is

47
expensive and its effects are only temporary - it needs to be continued
until the acid rain stops. The people of Norway and Sweden have
successfully used liming to help restore lakes and streams in their
countries.
A major liming programme has been taking place in Wales where
12,000 km of its waterways were acidified. In 2003, liming of the river
Wye led to a return of the salmon which had completely disappeared in
1985. However, other parts have taken longer to recover and there are
still no signs of life.
Recently a more positive side of acid rain has been noted as it can
be very effective at reducing the natural production of methane, a
“greenhouse gas” approximately 23 times more powerful than carbon
dioxide, especially in wetland areas.
What can we do to help?
Reduce emissions
• Burning fossil fuels is
still one of the cheapest ways to
produce electricity so people are
now researching new ways to
burn fuel which don't produce
so much pollution.
• Governments need to
spend more money on pollution
control even if it does mean an
increase in the price of
electricity.
• Sulphur can also be 'washed' out of smoke by spraying a mixture
of water and powdered limestone into the smokestack.
• Cars are now fitted with catalytic converters which remove three
dangerous chemicals from exhaust gases.
Find alternative sources of energy
• Governments need to invest in researching different ways to
produce energy.
• Two other sources that are currently used are hydroelectric and
nuclear power. These are 'clean' as far as acid rain goes but what other
impact do they have on our environment?

48
 • Other sources could be solar energy or windmills but how
reliable would these be in places where it is not very windy or sunny?
• All energy sources have different benefits and costs and all
theses have to be weighed up before any government decides which of
them it is going to use.
Conserving resources
• Greater subsidies of public transport by the government to
encourage people to use public transport rather than always travelling
by car.
• Every individual can make an effort to save energy by switching
off lights when they are not being used and using energy-saving
appliances - when less electricity is being used, pollution from power
plants decreases.
• Walking, cycling and sharing cars all reduce the pollution from
vehicles.
(Young people’s trust for the Environment, n.d.)

49
 5 NOISE POLLUTION
Work with a partner and answer the questions below
1. What are the sounds that we hear every day?
2. What sounds do you find the most irritating?
3. What are possible effects of noise pollution?
4. What can be done to control noises?

50
 READING
The word noise is derived from the Latin term nauea. Noise has
been defined as a sound without agreeable quality or as unwanted or
undesirable sound. This is a subjective definition as some desirable sound
for somebody (fast music) may be noise for some other person. So
defining it in a better way we can say that noise is wrong sound in the
wrong place at the wrong time. A given sound is pleasant when soft but
noisy when loud. It may be acceptable for a short time but unacceptable
when prolonged. It may be intriguing when rhythmic but noise when
randomly repeated. Noise is defined in law as, excessive, offensive,
persistent or startling sound.
Like air and water pollution, noise is also emerging fast as a major
pollutant to the environment. The roar of jet planes, honking of buses, the
screeching of rushing vehicles, wailing of emergency vehicle siren,
whistling of railway engines, back fire from motor vehicles, the din of
factories and the thunder of construction machinery, are contributing to
the high level of noise. The noise is just not confined to the urban area
but the countryside is also being shaken by the rattle of motorized farm
implements, pump sets, tractors, buzzing of motor vehicles, etc. Along
with these the increasing use of televisions, sound systems and
loudspeakers without any check on their volume is also contributing to
the growing noise levels.
Noise problem can be divided into two categories. The first is the
community noise wherein one is concerned with annoyance caused to
people in their indoor environment. It is the instruction of noise inside the
dwellings above the allowable level mainly from vehicular traffic. The
other is the intense sound that exists in some workplaces like factories
and traffic islands where there is a real danger of permanent physical
damage.
Prolonged exposure to excessive noise produces adverse
physiological effects such as hypertension, annoyance, disturbance in
sleep and deafness, etc.
The noise has so far not been regarded as a fatal pollutant because
so far it was within limits. Except in industrial areas and big cities, noise
pollution was not prominent and hence generally remained ignored from
being treated as an environment pollutant. With the increasing
industrialization and commercialization of society and with consequential
increase in noise producing automobiles and machines, noise has become
a slow poison to mankind. It is a matter of thought that whether we
51
should accept the increased noise as a price for progress or should shun
the new technological advance all together to lead scheduled life. The
other better way is to devise and implement noise controlling techniques
to reduce the adverse impacts of noise.

EFFECTS OF NOISE
There is a bad effect of noise on human health depending upon the
noise level, exposure time and the health conditions. The effects of noise
can be classified in the following ways: Psychological and physiological
effects: the noise of different levels has different psychological and
physiological effects. The following table shows some of them.

Actually, the acceptance level of noise depends upon the state of

mind and the expectation of a listener. A person can bear the monotonous
sound in a sleeper coach of a train as high as 70 dB and sleep
comfortably as he expects it and mentally prepared for it. The same
person may get disturbed even by the ticking of a clock at 20 dB in his
bedroom.
ADVERSE EFFECTS OF NOISE
1. Effects on Human Body Function
Exposure to noise is likely to bring about activation of sympathetic
nervous system in a similar way as heat, cold, pain etc. One of the short
time reactions is the change in blood circulation. The other effects on
brain and other organs are the increased release of insulin in pancreas,
increase in the secretion of oxytocin and ADH from posterior and it also
decreases the detoxifying function of the liver including aromatic
substances with carcinogenic effects. Long time noise can produce
stomach ulcer, reduced flow of gastric juice and change in acidity

52
neurosis, allergies and circulatory disease, abortion and other congenial
defects in children, deafness, etc.
2. Sleep Interference
The main annoying effect of noise is the interruption on sleep.
Sleep is a must and even one nights missed sleep may disturb us. One can
become short tempered and weary. Noise can interfere with sleep even
when the sleeping person is not awakened.
3. Effect on Working Efficiency
It has been proved that the working efficiency reduces with
increase in noise. Reduction in noise from 96 dB to 87 dB has increased
the performance by 12%. Reduction of noise either by sound proofing or
putting sound obstructing barriers improves the quality of work. It also
reduces the industrial accidents. The noise affects communication signals
so reduction of noise increases the efficiency.
4. Effect on Wild Life
Noise produces physiological effects on human as well as animal
health. It has been surveyed that noise has adversely affected the wildlife
of the country. It has been observed by the zoo authorities that animals
particularly deer, lions, rhino etc. are the worst affected ones by the
traffic noise. They become dull, inactive, lesser reproductive and ill.
Even the migratory birds are reduced if there is noise. In the forests
because of the human activity the noise increases and the animals like
lion, tiger and elephants feel segmentation and their reproduction is
automatically reduced.
5. Effects on Non-living Things
Noise affects even the non-living things. High intensity noise may
produce cracks into buildings. The noise and vibrations from machinery
result in shattering of foundations, loosening of plaster and cracks in
walls and house hold crockery.
(Gaur, 2007, pp. 183 - 192)

Task 1: Read the passage carefully and answer the following questions
1. What is noise pollution?
2. How many categories is noise problem divided? What are
they?
3. What problem does noise prolonged exposure cause?
53
 4. Is noise pollution considered serious problem by citizens?
Why?
5. What will affect the impact of noise on human health?
6. What happens to a person who shortly exposes to 120 dB
environment?
7. What are the main effects of noise pollution on human life?
8. How does the noise pollution affect animal life?
9. How does high intensive noise may cause to non-living things?
10. What affects acceptance level of noise of a particular person?

CONTROL OF NOISE POLLUTION

Though the noise cannot be totally eliminated but can be reduced
by adopting certain measures. The basic principals of noise control are as
follows.
1. Noise Control at Source
In an industry to control the noise at source the machinery should
be equipped by effective silencers, properly installed on the designed
foundation and well maintained. Use of shock absorbing material,
efficient flow technique, reducing fluid jet velocities, restricting sound
producing area, reducing peak accelerations are some of the techniques
of noise control at source. Use of guards, covers, enclosures and muffler
systems, sealing all openings, use of proper cutting speeds and feed rate
are other ways of noise reduction. The proper maintenance of machines
by lubrication and timely replacement of bearings is the main thing
required for the control of noise at source.
2. Noise Control along the Path
The modification of sound path includes:
 Use of solid high barriers to interrupt the direct transmission.
Solid fences and high earth berms can be provided up to attenuation
along the highways.
 Increasing distance between the source and the receiver.
 By planting trees. Trees are very good absorber of the sound and
otherwise also very much useful as described earlier.

54
 3. Noise Control at Receiving End
To control the noise at receiver level, following measures are
adopted.
 Double glazing windows in the building for improved sound
proofing.
 Gasketing and sealing door and windows openings.
 Providing additional sound insulation for roofs and walls.
 Isolate the operator from the noise.
 By controlling hours of exposure to noise.
 Use of personal protective devices like ear plugs, ear defenders,
disposable ear plugs, etc.
4. Other Ways of Noise Control
Forming legislation for noise levels for various types of equipment,
land use pattern, declaration of silence zone, restricting the use of
loudspeakers are some of the ways of noise reduction. Actually, there are
rules and regulations but their implementation is difficult without the co-
operation of masses. Educating people about hazards of noise pollution
and developing awareness at all levels can solve the problem. The social
workers should come up to ban the use of bands, orchestras, DJs in the
marriages and other functions. The engineers should design the
equipment with minimum noise. The industrialists have to install and
maintain the equipment and machinery properly. The vehicle drivers
should owe to restrict the unnecessary use of horns of the vehicles. The
students should owe to stop the use of crackers on festivals and other
moments of joy. The demonstration should be silent ones. Society in
general can reduce the noise pollution if it really wants so.
(Gaur, 2007, pp. 193 - 194)

Tasks 2: Read the passage carefully to decide whether the following

sentences are TRUE or FALSE
1. Reducing fluid jet velocities are the technique of noise control
along the path.
2. Maintenance of machines by lubrication is one of the main
things required for the control of noise at source.

55
 3. Sealing all openings is not a good way to control the noise.
4. High earth berms are one of high solid barriers which are useless
to control the noise along the path.
5. Moving factories to suburb areas is an example of controlling
the noise at sources.
6. Wearing ear plugs is one way to control the noise along the path.
7. According to the passage, use of bands in weddings may be
banned due to the need of noise reduction.
8. Education cannot help to improve the problem.

Task 3: Fill the text below with ONE word in the box, you can use
words twice
measures protection health ailments
pressure law penalized absorption
efforts source banned causes
level exposure rural
The noise __(1)__is increasing day by day in urban and
___(2)__both environment. It is detrimental in many ways and
particularly for human ___(3)__. It ___(4)___annoyance, irritation,
headache, insomnia, fatigue, mental disorders, increased perspiration,
nausea, high blood pressure, high pulse rate and other human __(5)___.
All ___(6)___should be adopted to reduce noise at __(7)__level. If it is
not possible to cut down the noise then ___(8)___should be made to
reduce it in between , by say __(9)___by trees. Even then if the sound
reaching the listener is higher than permitted, personal ___(10)__should
be done by using ear plugs or dampeners. The duty hours should be such
that prolonged ___(11)___to noise is restricted. The cities should be
planned in such a way that heavy traffic is always bypassed and the other
traffic should have a timely entry. The vehicles with distorted silencers
should be heavily __(12)___. Overloaded trucks produce more noise. Use
of horns should be limited and __(13)___horns should be totally
___(14)___. Use of loudspeakers should be banned and all processions
on the roads should be banned. Use of fire crackers making loud sound,
on festivals and other events should be restricted by __(15)__, rather
banning their production. Sound proofing should be done in factories and

56
industries and offices. By adopting all these measures the aim of noise
control can be achieved.
(Adapted from Gaur, 2007)

TRANSLATION
Task 1: Translate the following passage into Vietnamese
Adverse Effects of Noise Pollution on Wildlife
Noise can have a detrimental effect on wild animals, increasing the
risk of death by changing the delicate balance in predator or prey
detection and avoidance, as well as interfering the use of the sounds in
communication, especially in relation to reproduction and in navigation.
Acoustic overexposure can lead to temporary or permanent loss of
hearing.
An impact of noise on wild animal life is the reduction of usable
habitat that noisy areas may cause, which in the case of endangered
species may be part of the path to extinction. Noise pollution has caused
the death of certain species of whales that beached themselves after being
exposed to the loud sound of military sonar.
Noise also makes species communicate more loudly, which is
called Lombard vocal response. Scientists and researchers have
conducted experiments that show whales' song length is longer when
submarine-detectors are on. If creatures do not ‘speak’ loudly enough,
their voice will be masked by anthropogenic sounds. These unheard
voices might be warnings, finding of prey, or preparations of net-
bubbling. When one species begins speaking more loudly, it will mask
other species' voice, causing the whole ecosystem eventually to speak
more loudly.
Marine invertebrates, such as crabs, have also been shown to be
impacted by ship noise. Larger crabs were noted to be impacted more by
the sounds than smaller crabs. Repeated exposure to the sounds did lead
to acclimatization.
European robins living in urban environments are more likely to
sing at night in places with high levels of noise pollution during the day,
suggesting that they sing at night because it is quieter and their message
can propagate through the environment more clearly. The same study
showed that daytime noise was a stronger predictor of nocturnal singing

57
than night-time light pollution, to which the phenomenon is often
attributed.
Zebra finches become less faithful to their partners when exposed
to traffic noise. This could alter a population's evolutionary trajectory by
selecting traits, sapping resources normally devoted to other activities
and thus leading to profound genetic and evolutionary consequences.
(Wikipedia, 2013)

Task 2: Translate the following passage into English

Tiếng ồn ở đây là cộng hưởng âm thanh của tất cả phương tiện lưu
thông, đặc biệt là tiếng còi hơi của xe buýt và xe tải.
Mặc dù chúng ta có quy định về tiếng ồn ở khu dân cư, các thông
số kỹ thuật cho phương tiện lưu thông, cấm lắp đặt còi hơi nhưng người
đi đường vẫn giật mình vì tiếng còi hơi mà xe buýt và xe tải tự cải tiến.
TP.HCM nói riêng và các thành phố lớn nói chung có rất nhiều
phương tiện lưu thông, điều này làm cho đô thị vốn đã ồn càng ồn hơn
với các tiếng còi xe và mức chịu tác động của người dân cũng nhiều hơn.
Ở mức độ vừa phải, tiếng ồn không nguy hại đến sức khỏe, nhưng
việc tiếp xúc với tiếng ồn cường độ cao (> 75 dB) trong thời gian dài sẽ
gây bệnh điếc không hồi phục và tác động lên hệ thần kinh gây mệt mỏi,
stress gián tiếp, làm tăng các bệnh tim mạch, bệnh đường tiêu hóa.
Cơ chế gây bệnh của tiếng ồn hiện nay chưa rõ nhưng người ta
nhận thấy các tế bào cảm nhận âm thanh ở vùng đáy của ốc tai (thuộc tai
trong) bị tổn thương và sự tổn thương này không hồi phục được.
Triệu chứng ban đầu là người bệnh không tập trung, mệt mỏi, khó
nghe người nói chuyện bình thường trong môi trường ồn ào, đặc biệt là
các phụ âm, sau đó là các tiếng u u ve ve trong tai. Giảm thính lực, stress
sẽ ảnh hưởng lớn đến khả năng học tập và năng suất lao động cũng như
chất lượng sống của người bệnh.
Công tác quản lý tiếng ồn là một thách thức lớn không chỉ ở đất
nước chúng ta mà trên cả thế giới (như cải thiện cơ sở hạ tầng, phương
tiện giao thông, tăng cường giao thông công cộng). Tuy nhiên trong điều
kiện chúng ta hiện nay, nhằm góp phần xây dựng một đô thị an toàn, văn
minh thì việc xử lý nghiêm các phương tiện giao thông vi phạm gây ồn là
cần thiết.

58
 Các cơ quan chức năng nên nghiên cứu việc đặt các biển hiệu cấm
tiếng còi xe trong nội thành thành phố để góp phần giảm tiếng ồn cho đô
thị, bảo vệ sức khỏe cho cộng đồng.
(Nguyen, 2007)

59
 6 WATER POLLUTION

Look at the pictures and discuss in groups to answer the questions below.
Note down your ideas.

1 2

3 4

5 6
3

1. What do think water pollution is?

2. Is water pollution a serious problem nowadays? Why?
3. What effects of water pollution do you think of ?

60
 4. What sources of water pollution do you think of?

READING
Water pollution is the phenomenon when natural water bodies are
contaminated by chemical, physical, radioactive or pathogenic microbial
substances. It occurs when pollutants are directly or indirectly discharged
into water bodies without adequate treatment to remove harmful
compounds.
It is a major global problem which requires ongoing evaluation and
revision of water resource policy at all levels (international down to
individual aquifers and wells). It has been suggested that it is the leading
worldwide cause of deaths and diseases and that it accounts for the
deaths of more than 14,000 people daily. Developing and developed
countries continue to struggle with the acute problems of water pollution
as well. In the most recent national report on water quality in the United
States, 45 % of assessed stream miles, 47% of assessed lake acres, 32%
of assessed bays and estuarine square miles were classified as
polluted. Around 90% the water in the cities of China is polluted and as
of 2007, half a billion Chinese had no access to safe drinking water. An
estimated of 580 people in India die of water pollution related illness
every day.
CATEGORIES
Point sources
Point sources of water pollution are described by the CWA as "any
discernible, confined and discrete conveyance from which pollutants are
or may be discharged." These include pipes or man-made ditches from
stationary locations such as sewage treatment plants, factories, industrial
wastewater treatment facilities, septic systems and other sources that are
clearly discharging pollutants into water sources.
Nonpoint sources
Nonpoint source pollution refers to diffuse contamination that does
not originate from a single discrete source. This kind of water pollution is
often the cumulative effect of small amounts of contaminants gathered
from a large area. Common examples are the leaching out of nitrogen
compounds from fertilized agricultural lands, and the nutrient runoff in
storm water form ‘sheet flow’ over an agricultural field or a forest.

61
 Contaminated storm water washed off of parking lots, roads and
highways, called urban runoff, is sometimes included under the category
of nonpoint sources pollution. However, this runoff is typically
channeled into storm drain systems and discharged through pipes to local
surface waters, and is a point source.
(Wikipedia, 2014a)
CAUSES
Most of water has been being polluted by human being through
industrial activities, marine dumping, mining, oil leaking, etc. Besides,
natural phenomena such as volcanoes, algae blooms, storms and
earthquakes also cause enormous changes in water quality and the
ecological status of water.
Industrial waste: Industries produce huge amount of waste which
contains toxic chemicals and pollutants, such as lead, mercury, sulphur,
asbestos, nitrates and many other harmful chemicals. Many industries do
not have proper waste management system and drain the waste in the
fresh water which goes into rivers, canals and later into the sea. The toxic
chemicals have the capability to change the color of water, increase the
amount of minerals, also known as Eutrophication, change the
temperature of water and pose serious hazard to water organisms.
Sewage and wastewater: The sewage and waste water that is
produced by each household is chemically treated and released into the
sea with fresh water. The sewage water carries harmful bacteria and
chemicals that can cause serious health problems. Pathogens are known
as a common water pollutant. The sewers of cities house several
pathogens and thereby diseases. Microorganisms in water are known to
be causes of some very deadly diseases and become the breeding grounds
for other creatures that act like carriers. These carriers inflict these
diseases via various forms of contact onto an individual. A very common
example of this process would be Malaria.
Mining activities: Mining is the process of crushing the rock and
extracting coal and other minerals from underground. These elements,
when extracted in the raw form, contain harmful chemicals and can
increase the amount of toxic elements when mixed up with water which
may result in health problems. Mining activities emit several metal waste
and sulphides from the rocks and is harmful for living objects.
Marine dumping: The garbage produce by each household in the
form of paper, aluminum, rubber, glass, plastic, food if collected and
deposited into the sea in some countries. These items take from 2 weeks
62
to 200 years to decompose. When such items enter the sea, they not only
cause water pollution but also harm animals in the sea.
Accidental oil leakage: Oil spill pose a huge concern as large
amount of oil enters into the sea and does not dissolve in water. This can
cause varying damage to species in the ocean depending on the quantity
of oil spill, size of ocean, toxicity of pollutant.
Chemical fertilizers and pesticides: Chemical fertilizers and
pesticides, used by farmers to protect crop, are useful for the plants
growth. However, when it rains, the chemicals mixed up with rainwater
and flow down into rivers and canals which pose serious damages for
aquatic animals.
Global warming: The raise in earth’s temperature increases the
water temperature and results in death of aquatic animals and marine
species, later resulting in water pollution.
Animal waste: The waste produced by animals is washed away
into the rivers when it rains. It gets mixed up with other harmful
chemicals and causes various water borne diseases like cholera, diarrhea,
jaundice dysentery and typhoid.
(Converse-energy future, 2014)

Task 1: Decide whether the following sentences are True (T) or False
(F)
1. ___ Water pollution will happen if pollutants are directly
discharged into water bodies with adequate treatment.
2. ___ Water pollution is a major local problem which requires
ongoing evaluation and revision of water resource policy at all
levels.
3. ___ According to the passage, only one fourteenth of Chinese
can have drinkable water.
4. ___ Pipes which carry pollutants from the power plants to the
rivers are examples of nonpoint source pollution.
5. ___ Nutrient runoff in storm water from a grapevine is an
example of nonpoint source pollution.
6. ___ Only human activities have been polluted the water up to
now.

63
 7. ___ Eutrophication is the change in temperature of water and
can pose serious hazard to water organisms.
8. ___ Malaria is one of deadly diseases, which cause from
microorganisms in water.
9. ___ According to the passage, paper and food take from 2 weeks
to 200 years to decompose.
10. ___ Mining process becomes more harmful with the presence
of water.
11. ___ Death of aquatic animals cannot pollute a water body.
12. ___ Oil leakage is very dangerous to aquatic animals because it
does not dissolve in water.

Task 2: Match the appropriate definition for the words in the left column
1. Acute a) A thing that causes disease
2. Ditch b) A type of water pollution, such as pipes or
man-made ditches from stationary locations
3. Septic system
c) The process of taking somebody/something
4. Pathogen
from one place to another
5. Point source
d) Very serious or severe
6. Nonpoint
e) The cumulative effect of small amounts of
source
contaminants gathered from a large area
7. Conveyance
f) An effective, long-standing method for
8. Leakage collecting, treating, and disposing of sewage
from rural and suburban homes
g) An amount of liquid or gas escaping through
a hole in something
h) A long channel dug at the side of a field or
road to hold or take away water

Control of water pollution

Decisions on the type and degree of treatment, the control of
wastes, and the disposal and use of adequately treated wastewater must
be based on considering all the technical factors of each drainage basin in
order to prevent any further contamination or harm to the environment.
64
 Domestic sewage
In urban areas, domestic sewage is typically treated by centralized
sewage treatment plants. Well-designed and operated systems (i.e.,
secondary treatment or better) can remove 90 percent or more of these
pollutants. Some plants have additional systems to remove nutrients and
pathogens. However, most municipal plants are not specifically designed
to treat toxic pollutants found in industrial waste water.
A household or business not served by a municipal treatment plant
may have an individual septic tank, which treats the wastewater on site
and discharges into the soil. Alternatively, domestic wastewater may be
sent to a nearby privately owned treatment system (e.g. in a rural
community).
Industrial wastewater
Industries that generate wastewater with high concentrations of
conventional pollutants (e.g. oil and grease), toxic pollutants (e.g. heavy
metals, volatile organic compounds) or other non-conventional pollutants
such as ammonia, need specialized treatment systems. Some of these
facilities can install a pre-treatment system to remove the toxic
components then send the partially treated wastewater to the municipal
system.
Agricultural wastewater
Nonpoint source controls
Sediment (loose soil) washed off fields is the largest source of
agricultural pollution in the United States. Farmers may utilize erosion
controls to reduce runoff flows and retain soil on their fields. Common
techniques include contour plowing, crop mulching, crop rotation,
planting perennial crops and installing riparian buffers. To minimize
pesticide impacts, farmers may use Integrated Pest Management (IPM)
techniques (which can include biological pest control) to maintain control
over pests, reduce reliance on chemical pesticides and protect water
quality.
Point source wastewater treatment
Farms with large livestock and poultry operations, such as factory
farms, are called concentrated animal feeding operations or feedlots in
the US and are being subject to increasing government regulation.
Animal slurries are usually treated by containment in anaerobic lagoons
before disposal by spary or trickle application to grassland. Constructed
wetlands are sometimes used to facilitate treatment of animal wastes.
65
Some animal slurries are treated by mixing with straw and composted at
high temperature to produce a bacteriologically sterile and friable manure
for soil improvement.
Urban runoff
Local governments use a varirty of storm water management
techniques to reduce the effects of urban runoff. These techniques, called
best management practices (BMPs) in the U.S., may focus on water
quantity control, while others focus on improving water quality, and
some perform basins, bioretention system, constructed etlands, retention
basins and similar devices.
Thermal pollution from runoff can be controlled by storm water
management facilities that absorb the runoff or direct it into ground
water, such as bioretention systems and infiltration basins.
(Wikipedia, 2014)
Task 3: Read the passage carefully and answer the following questions
1. How many ways are there to control water pollution? What are
they?
2. What must be put under consideration when we decide on type
and degree of treatment?
3. Where is the household wastewater treated?
4. Why is industrial wastewater usually treated before it is sent to
municipal treatment plants?
5. How do the farmers minimize water pollution from pesticide?
6. How are animal slurries treated?

Task 4: Fill in the blank with given words or phrases in the box
IPM techniques composting bioretention
crop rotation specialized treatment system secondary treatment
1. ____________ is often used in runoff treatment.
2. ___________ at high temperature can reduce water
pollution from animal waste.
3. Farmers can reduce runoff flow and retain soil on their
fields by __________ .

66
 4. ___________ is required to remove toxic pollutants in
industrial waste water.
5. 90% or more of pollutants can be removed from waste
water in a system with __________ or more.
6. _________ can help farmers reduce reliance on pesticides.

TRANSLATION
Task 1: Translate the following passage into Vietnamese
There are several classes of water pollutants. The first are disease-
causing agents. These are bacteria, viruses, protozoa and parasitic worms
that enter sewage systems and untreated waste.
A second category of water pollutants is oxygen-demanding
wastes; wastes that can be decomposed by oxygen-requiring bacteria.
When large populations of decomposing bacteria are converting these
wastes, they can deplete oxygen levels in the water. This causes other
organisms in the water – such as fish – to die.
A third class of water pollutants is water-soluble inorganic
pollutants, such as acids, salts and toxic metals. Large quantities of these
compounds will make water unfit to drink and will cause the death of
aquatic life.
Another class of water pollutants are nutrients; they are water-
soluble nitrates and phosphates that cause excessive growth of algae and
other water plants, which deplete the water's oxygen supply. This kills
fish and, when found in drinking water, can kill young children.
Water can also be polluted by a number of organic compounds such as
oil, plastics and pesticides, which are harmful to humans and all plants
and animals in the water. A very dangerous category is suspended
sediment, because it causes depletion in the water's light absorption and
the particles spread dangerous compounds such as pesticides through the
water.
Finally, water-soluble radioactive compounds can cause cancer,
birth defects and genetic damage and are thus very dangerous water
pollutants.
(Lenntech, 2014)

67
Task 2: Translate the following passage into English
Trong hầu hết các quá trình sản xuất, rất nhiều nhiệt sẽ phải được
thải vào môi trường, đó là nhiệt thải. Thông thường, để làm giảm nguồn
nhiệt này một cách nhanh chóng, người ta dẫn nước từ những nguồn gần
đó, đưa qua các nhà máy để làm nguội máy móc và thải nước nóng trở lại
nguồn nước. Nhiệt lưu hành trong nước có tác động tiêu cực lên cuộc
sống của các loài sinh vật sống dưới nước. Loại ô nhiễm này thường
được gọi là ô nhiễm nhiệt.
Nước ấm làm giảm độ hòa tan của oxy trong nước và nó cũng
khiến các sinh vật nước thở nhanh hơn. Vì vậy, nhiều sinh vật nước sẽ
chết vì thiếu oxy hoặc trở nên nhạy cảm hơn với bệnh tật.

FURTHER READING
Water Quality Parameters and Definitions
Parameters Reason for the analysis
Chemical Parameters
Temperature Temperature can exert great control over aquatic
communities. If the overall water body temperature of
a system is altered, an aquatic community shift can be
expected.
In water above 30oC, a suppression of all benthic
organisms can be expected. Also, different plankton
groups will flourish under different temperatures. For
example, diatoms dominate at 20 – 25oC, green algae
dominate at 30 – 35oC, and cyano-bacteria dominate
above 35oC.
pH value pH is an indicator of the existence of biological life as
most of them thrive in a quite narrow and critical pH
range.
Dissolved DO is essential for aquatic life. A low DO (less than 2
Oxygen (DO) mg/l) would indicate poor water quality and thus
would have difficulty in sustaining many sensitive
aquatic life.
Colour (Hazen) Colour is vital as most water users, be it domestic or
industrial, usually prefer colourless water.
Determination of colour can help in estimated costs

68
 related to discolouration of the water.

Conductivity Conductivity indicates the presence of ions within the

water, usually due to in majority, saline water and in
part, leaching. It can also indicate industrial
discharges.
The removal of vegetation and conversion into
monoculture may cause run-off to flow out immediate
thus decrease recharge during drier period. Hence,
saline intrusion may go upstream and this can be
indicated by higher conductivity.
Turbidity Turbidity may be due to organic and/or inorganic
(Nephelometric constituents. Organic particulates may harbour
Turbicity Units microorganisms. Thus, turbid conditions may increase
- NTU) the possibility for waterborne disease. Nonetheless,
inorganic constituents have no notable health effects.
The series of turbidity-induced changes that can occur
in a water body may change the composition of an
aquatic community. First, turbidity due to a large
volume of suspended sediment will reduce light
penetration, thereby suppressing photosynthetic
activity of phytoplankton, algae and macrophytes,
especially those farther from the surface. If turbidity is
largely due to algae, light will not penetrate very far
into the water and primary production will be limited
to the uppermost layers of water. Cyanobacteria (blue-
green algae) are favoured in this situation because they
possess flotation mechanisms. Overall, excess turbidity
leads to fewer photosynthetic organisms available to
serve as food sources for many invertebrates. As a
result, overall invertebrate numbers may also decline,
which may then lead to a fish population decline.
If turbidity is largely due to organic particles,
dissolved oxygen depletion may occur in the water
body. The excess nutrients available will encourage
microbial breakdown, a process that requires dissolved
oxygen. In addition, excess nutrients may result in
algal growth. Although being photosynthetic by day,
algae respire at night, using valuable dissolved oxygen.
Fish kills often result from extensive oxygen depletion.
69
Salinity High salinity may interfere with the growth of aquatic
vegetation. Salt may decrease the osmotic pressure,
causing water to flow out of the plant to achieve
equilibrium. Less water can be absorbed by the plant,
causing stunted growth and reduced yields. High salt
concentrations may cause leaf tip and marginal leaf
burn, bleaching or defoliation.
As per Conductivity, Salinity (NaCl content, g/kg) can
be used to check for possible saline intrusion in future.
Total Total Suspended Solids is an indication of the amount
Suspended of erosion that took place nearby or upstream. This
Solids, TSS parameter would be the most significant measurement
as it would depict the effective and compliance of
control measures e.g. riparian reserve along the
waterways.
The series of sediment-induced changes that can occur
in a water body may change the composition of an
aquatic community. First, a large volume of suspended
sediment will reduce light penetration, thereby
suppressing photosynthetic activity of phytoplankton,
algae and macrophytes. This leads to fewer
photosynthetic organisms available to serve as food
sources for many invertebrates. As a result, overall
invertebrate numbers may also decline, which may
then lead to decreased fish populations.
In addition, sediment may interfere with essential
functions of organisms. The numbers of filter-feeding
invertebrates will decline if their filter mechanisms are
choked by suspended particles. Some zooplankton
suffer decline due to clogged feeding mechanisms.
Likewise, fish may suffer clogging and abrasive
damage to gills and other respiratory surfaces.
Abrasion of gill tissues triggers excess mucous
secretion, decreased resistance to disease, and a
reduction or complete cessation of feeding. Suspended
sediment may also affect predator-prey relationships
by inhibiting predators' visual abilities.
Reproductive success may decline with an increase in
fine sediment. If spawning habitats are altered by
70
sediment deposition (e.g., filling of pools and riffles or
covering of a gravel bed), fish may be unable to lay
eggs. If eggs are successfully produced, the incubation
period may be in jeopardy because 1) a shifting-
sediment environment is unstable, and 2) burial by fine
sediment prevents circulation of water around the egg,
decreasing oxygenation. The egg will suffocate and
may be poisoned by its own metabolic waste. If eggs
do hatch into fry, the young may be less likely to
survive in less-than-optimum conditions.
The settling of suspended solids from turbid waters
threatens benthic aquatic communities. Deposited
particles may obscure sources of food, habitat, hiding
places, and nesting sites. Most aquatic insects will
simply drift with the current out of the affected area.
Benthic invertebrates that prefer a low-silt substrate,
such as mayflies, stoneflies, and caddis flies, may be
replaced by silt-loving communities of oligochaetae,
pulmonate snails, and chironomid larvae.
Increased sediment may impact plant communities.
Primary production will decline because of a reduction
in light penetration. Sediment may damage plants by
abrasion, scouring, and burial. Finally, sediment
deposition may encourage species shifts because of a
change of substrate.
Sediment deposition may also affect the physical
characteristics of the stream bed. Sediment
accumulation causes stream bed elevation and a
decrease in channel capacity. Flooding is more likely
after sediment accumulation because the stream can
not accommodate the same volume of water. Also, a
substrate that is closer to the surface receives more
light and supports increased numbers of photosynthetic
organisms, such as rooted algae. As a result,
recreational use may be threatened because moving
parts of boats may become tangled in aquatic plants.
Sediment, which is generally negatively charged,
attracts positively charged molecules. Some of these
molecules (phosphorus, heavy metals, and pesticides)
are pollutants. These positively charged pollutants are

71
 in equilibrium with the water column and are often
released slowly into the water resource.

Total Dissolved The total dissolved solids (TDS) in water consist of

Solids, TDS inorganic salts and dissolved materials. In natural
waters, salts are chemical compounds comprised of
anions such as carbonates, chlorides, sulphates, and
nitrates (primarily in ground water), and cations such
as potassium (K), magnesium (Mg), calcium (Ca), and
sodium (Na). In ambient conditions, these compounds
are present in proportions that create a balanced
solution. If there are additional inputs of dissolved
solids to the system, the balance is altered and
detrimental effects may be seen. Inputs include both
natural and anthropogenic source.
Biochemical BOD is a measure of organic pollution to both waste
Oxygen and surface water. High BOD is an indication of poor
Demand, BOD water quality. For this tree plantation project, any
discharge of waste into the waterways would affect the
water quality and thus users downstream.
Chemical COD is an indicator of organics in the water, usually
Oxygen used in conjunction with BOD.
Demand, COD High organic inputs trigger deoxygenation. If excess
organics are introduced to the system, there is potential
for complete depletion of dissolved oxygen. Without
oxygen, the entire aquatic community is threatened.
The only organisms present will be air- breathing
insects and anaerobic bacteria.
If all oxygen is depleted, aerobic decomposition ceases
and further organic breakdown is accomplished
anaerobically. Anaerobic microbes obtain energy from
oxygen bound to other molecules such as sulphate
compounds. Thus, anoxic conditions result in the
mobilization of many otherwise insoluble compounds.
In areas of high organics there is frequently evidence
of rapid sewage fungus colonization. Sewage fungus
appears as slimy or fluffy cotton wool-like growths of
micro-organisms which may include filamentous
bacteria, fungi, and protozoa such as Sphaerotilus
72
 natans, Leptomitus lacteus, and Carchesium
polypinuym, respectively. The various effects of the
sewage fungus masses include silt and detritus
entrapment, the smothering of aquatic macrophytes,
and a decrease in water flow velocities. An
accumulation of sediment allows a shift in the aquatic
system structure as colonization by silt-loving
organisms occur. In addition, masses of sewage fungus
may break off and float away, causing localized areas
of dissolved oxygen demand elsewhere in the water
body.
Organic levels decrease with distance away from the
source. In a standing water body such as a lake,
currents are generally not powerful enough to transport
large amounts of organics. In a moving water body, the
saprotrophic organisms (organisms feeding on
decaying organic matter) break down the organics
during transportation away from the source. Hence,
there is a decline in the oxygen demand and an
increase of dissolved oxygen in the water. Community
structure will gradually return to ambient with distance
downstream from the source.
Ammoniacal Ammonia levels in excess of the recommended limits
Nitrogen may harm aquatic life. Although the ammonia
molecule is a nutrient required for life, excess
ammonia may accumulate in the organism and cause
alteration of metabolism or increases in body pH. It is
an indicator of pollution from the excessive usage of
ammonia rich fertilisers.
Potassium Potassium is macro nutrient element for plant growth.
It can occur naturally in minerals and from soils. High
levels in surface water, especially in areas where there
are agricultural activities as indicative of introduction
of K due to application of fertilisers.
Nitrate The growth of macrophytes and phytoplankton is
Nitrogen stimulated principally by nutrients such as nitrates.
Many bodies of freshwater are currently experiencing
influxes of nitrogen and phosphorus from outside
sources. The increasing concentration of available
phosphorus allows plants to assimilate more nitrogen
73
 before the phosphorus is depleted. Thus, if sufficient
phosphorus is available, high concentrations of nitrates
will lead to phytoplankton (algae) and macrophyte
(aquatic plant) production. This is mostly due to the
usage of fertilisers.
Oil & Grease To check if there is any indiscriminate dumping of
waste oil or poor management of oily waste within the
site.
Microbiological
Total Coliform Microbiological test is to detect the Level of pollutions
Count caused by living thing especially human who live or
work in the area especially upstream of the site.
Faecal
Coliform Count These tests are based on coliform bacteria as the
indicator organism. The presence of these indicative
organisms is evidence that the water has been polluted
with faeces of humans or other warm-blooded animals.
Pesticides
Chlorinated
Glyphosphate These parameters are common tests for the level of
agrochemical pollution. Since a specific type of
Paraquat
agrochemical to use is unknown at this stage, it is
Methamidaphos unknown at this stage the type of agrochemical that
would be used in the proposed development, a range of
test is recommended for analysing to gauge the
existing condition that could be used as baseline
information or reference.
(Environmental protection department, Malaysia, n.d.)

74
 7 WASTEWATER TREATMENT

Hydrologic cycle

There are six important processes that make up the water cycle:
condensation, infiltration, runoff, evaporation, precipitation and
transpiration. Match the terms with definitions/ descriptions.
1. Condensation A. The process where water changes from its liquid
state to a gaseous state.
2. Infiltration
B. As plants absorb water from the soil, the water
3. Runoff
moves from the roots through the stems to the
4. Evaporation leaves. Once the water reaches the leaves, some of
5. Precipitation it evaporates from the leaves, adding to the amount
of water vapor in the air.
6. Transpiration
C. It is an important process where rain water soaks
into the ground, through the soil and underlying
rock layers.
D. It occurs when a gas is changed into a liquid.
E. Much of the water that returns to Earth as
precipitation runs off the surface of the land, and
flows down hill into streams, rivers, ponds and lakes.
F. It occurs when the temperature and atmospheric
pressure are right, the small droplets of water in
clouds form larger droplets. The raindrops fall to
Earth.

75
 READING
OVERVIEW OF WASTEWATER TREATMENT PROCESS
Water is naturally cleaned and reused as part of the hydrologic
cycle in the outside world. In the human world, water is also cleaned and
reused. Our wastewater is channeled to a wastewater treatment plant
where it is cleaned and released back into lakes and rivers. This water
reenters the hydrologic cycle and will eventually be pumped back up by
another water treatment plant to be purified and released to customers.
Sources of Wastewater
You can classify wastewater as domestic, industrial or storm,
according to its origin. Domestic sources include water used for normal
activity in homes, businesses and institutions. Domestic wastewater is
readily treatable.
The character of industrial wastewater depends on the type of
industry using the water. Some industrial wastewaters can be treated the
same as domestic wastes without difficulty. Others may contain toxic
substances or high percentages of organic materials or solids which make
treatment difficult. In such cases, the industrial plant may have to pretreat
its wastewater to remove these pollutants or reduce them to treatable
levels before they are accepted into a publicly-owned treatment facility.
Storm water often goes to a treatment plant, although it is usually
low in pollutants. Great amounts of storm water can interfere with
treatment efficiency in two ways. First, storm water may cause too much
dilution of the wastewater. At the same time, it may cause hydraulic
overloading of the plant. In most cases, wastewater systems now call for
separate storm sewers.
In the Treatment Plant
In the treatment plant there are many steps involved in treating
wastewater. Below is a quick overview of the possible steps involved.
We will learn more about each step in the further reading section.
The general principle in wastewater treatment is to remove
pollutants from the water by getting them either to settle or to float, and
then removing this material. Some pollutants are easily removable.
Others must be converted to a settleable form before they can be
removed. Treatment facilities are designed in stages. Each stage either
removes particles from the wastewater or changes dissolved and

76
suspended material to a form that can be removed. A modern wastewater
treatment plant may include these stages:
 influent
 primary treatment
 secondary treatment
 tertiary treatment
 disinfection and effluent discharge

Influent
Influent is the raw material that has been collected and conveyed to
the plant for treatment. It includes all the water and debris that entered
the collection system.
Primary treatment
To prevent damage to pumps and clogging of pipes, raw
wastewater passes through mechanically raked bar screens to remove
large debris, such as rags, plastics, sticks and cans. Smaller inorganic
material, such as sand and gravel, is removed by a grit removal system.
The lighter organic solids remain suspended in the water and flow into
large tanks, called primary clarifiers. Here, the heavier organic solids
settle by gravity. These settled solids, called primary sludge, are removed
along with floating scum and grease, and then pumped to anaerobic
digesters for further treatment.
Secondary treatment
The primary effluent is then transferred to the biological or
secondary stage. Here, the wastewater is mixed with a controlled
population of bacteria and an ample supply of oxygen. The
microorganisms digest the fine suspended and soluble organic materials,
77
thereby removing them from the wastewater. The effluent is then
transferred to secondary clarifiers, where the biological solids or sludges
are settled by gravity. As with the primary clarifier, these sludges are
pumped to anaerobic digesters, and the clear secondary effluent may flow
directly to the receiving environment or to a disinfection facility prior to
release. There are several variations of secondary treatment, including:
 activated sludge
 trickling filtration
 rotating biological contactors (RBC)
 lagoons and ponds
Tertiary treatment
Tertiary, or advanced, wastewater treatment is the term applied to
additional treatment that is needed to remove suspended and dissolved
substances remaining after conventional secondary treatment. This may
be accomplished using a variety of physical, chemical or biological
treatment processes to remove the targeted pollutants. Advanced
treatment may be used to remove such things as color, metals, organic
chemicals and nutrients such as phosphorus and nitrogen.
Disinfection
Before the final effluent is released into the receiving waters, it
may be disinfected to reduce the disease-causing microorganisms that
remain in it. The most common processes use chlorine gas or a chlorine-
based disinfectant such as sodium hypochlorite. To avoid excess chlorine
escaping to the environment, the effluent may be dechlorinated prior to
discharge. Other disinfection options include ultraviolet light and ozone.
(Mountain empire community college, n.d.b)
Task 1: Match the stages in the wastewater treatment process with their
purposes/ functions
1. Preliminary a) It is designed to substantially degrade the
treatment biological contents of the sewage which are
derived from human waste, food waste, soaps and
2. Primary
detergent. This treatment process consists of the
treatment
biological treatment of wastewater by utilizing
3. Secondary many different types of microorganisms in a
treatment controlled environment.
4. Tertiary b) It is treatment of the effluent for the destruction

78
 treatment of all disease causing microorganisms. Another
term that is sometimes also used in describing the
5. Disinfection
destruction of microorganisms is sterilization.
Sterilization is the destruction of all
microorganisms. The procedures applied to
wastewaters will result in a substantial reduction
of all microbes so that bacterial numbers are
reduced to a safe level.
c) The term that is also sometimes used to indicate
treatment of a wastewater by methods other than
primary or biological (secondary) treatment is
advanced treatment. This degree of treatment is
usually achieved by chemical (for example
coagulation) methods as well as physical methods
(flocculation, settling and activated carbon
adsorption) to produce a high quality effluent water.
d) Its purpose is to protect the operation of the
wastewater treatment plant. This is achieved by
removing from the wastewater any constituents
which can clog or damage pumps, or interfere
with subsequent treatment processes.
e) It is designed to remove organic and inorganic
solids by the physical processes of sedimentation
and flotation. This stage of wastewater treatment
utilizes clarifiers or settling tanks which remove
the settleable organics and settleable inorganic
solids from the wastewater.

Task 2: Discuss the following questions in groups

1. What are sources of wastewater? Wastewater from which source
requires more effort to be treated? Why?
2. What stages may the wastewater treatment process involve?
Identify wastewater treatment methods (i.e. physical, chemical
or biological methods) used in each stage.
3. In your opinion, which stage is essential in wastewater
treatment?
4. Describe the wastewater treatment process in the treatment
plant, using the wastewater treatment diagram in the text.
79
 VOCABULARY
Task 1: What are meanings of the following prefixes? Give at least 3
examples to each prefix
Prefix Meaning Examples

de- …………………………… …………………………………

dis- …………………………… …………………………………
hydr(o)- …………………………… …………………………………
hypo- ………………………… …………………………………
micro- ………………………… …………………………………
over- ………………………… …………………………………
pre- ………………………… …………………………………
re- ………………………… …………………………………
trans- ………………………… …………………………………
ultra- ………………………… …………………………………

Task 2: Complete each sentence with the best option given

1. Wastewater treatment is closely related to the standards and/or
expectations set for the ______________ quality.
A. influent B. effluent C. organism D. micro-organism
2. _________digestion is a bacterial process that is carried out in
the absence of oxygen.
A. Organism B. Micro-organism C. Aerobic D. Anaerobic
3. Biological treatment methods use____________, mostly
bacteria, in the biochemical decomposition of wastewaters to
stable end products.
A. organisms B. microorganisms C. debris D. aeration
4. Preliminary treatment removes or cuts up the larger
___________and floating solids, removes the heavy inorganic
solids and removes excessive amounts of oils or greases.

80
A. suspended B. grit C. clogging D. colloidal
5. Solids left in the sedimentation tank bottom too long will gasify
and rise to the surface; therefore, _________ should be removed
from the tank as often as necessary.
A. grit B. grease C. sludge D. soluble
6. Comparison of ______________ versus effluent test results
provides information required to calculate and evaluate clarifier
efficiency.
A. debris B. sewer C. organic D. influent
7. You can add water to concentrated orange juice to __________
it until it reaches a concentration that is pleasant to drink.
A. dilute B. dissolve C. suspend D. clog
8. The rising cost of chlorine coupled with the fact that chlorine
even at low concentrations is toxic to fish and other biota as well
as the possibility that potentially harmful chlorinated
hydrocarbons may be formed has made chlorination less favored
as the ___________ of choice in wastewater treatment.
A. disinfection B. disinfectant C. disinfecting D. disinfected
9. _____________solids are frequently called mineral substances,
and include sand, gravel and silt as well as the mineral salts in
the water supply which produce the hardness and mineral
content of the water.
A. Inorganic B. Organic C. Suspended D. Settleable
10. Solids can also be grouped depending on their physical state as
suspended solids, colloidal solids and ___________solids,
each of which can include both organic and inorganic solids.
A. sediment B. raked C. soluble D. dissolved
11. ____________treatment can remove more than 99 percent of
all the impurities from sewage, producing an effluent of almost
drinking-water quality.
A. Preliminary B. Primary C. Secondary D. Tertiary
12. Storm flows from rains, storms and street washings will
contain grit, sand, leaves and other _____________from the
drained surfaces.
A. debris B. scum C. nutrients D. sludges
81
 TRANSLATION
Task 1: Translate the following paragraphs into Vietnamese
1. The purpose of wastewater treatment is generally to remove
from the wastewater enough solids to permit the remainder to be
discharged to a receiving water without interfering with its best
or proper use. The solids which are removed are primarily
organic but may also include inorganic solids. Treatment must
also be provided for the solids and liquids which are removed as
sludge. Finally, treatment to control odors, to retard biological
activity or destroy pathogenic organisms may also be needed.
2. Whether in the natural environment or a constructed water-
treatment plant, there are several key processes that occur during
water treatment: dilution, coagulation and flocculation, settling,
filtration, disinfection, and other chemical treatments. The
quality of the source water and the effectiveness of source-water
protection and management have a direct bearing on the
complexity of the treatment that is required. Source-water
protection is the first step in water treatment, with the natural
and engineered processes following.
3. The advantage of chlorination is that it continues to kill bacteria
as water moves through pipes to the tap. Its disadvantage is the
possibility of disinfection by-products. Excess chlorine in water
can combine with organic material in the water to form
substances such as trihalomethanes, which can cause liver,
kidney, or central nervous system problems, and are linked to an
increased risk of cancer over a lifetime exposure.

Task 2: Translate the following paragraphs into English

1. Nước thải sinh hoạt là nước thải phát sinh từ các hoạt động sinh
hoạt của các cộng đồng dân cư như: khu vực đô thị, trung tâm
thương mại, khu vực vui chơi giải trí, cơ quan công sở,… Thông
thường, nước thải sinh hoạt của hộ gia đình được chia làm hai
loại chính: nước đen và nước xám. Nước đen là nước thải từ nhà
vệ sinh, chứa phần lớn các chất ô nhiễm, chủ yếu là chất hữu cơ,
các vi sinh vật gây bệnh và cặn lơ lửng. Nước xám là nước phát
sinh từ quá trình rửa, tắm, giặt, với thành phần các chất ô nhiễm
không đáng kể.
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 2. Trong xử lý nước thải, quá trình lắng được sử dụng để loại bỏ
các tạp chất ở dạng huyền phù thô ra khỏi nước thải. Theo chức
năng, các bể lắng được phân thành: bể lắng cát, bể lắng sơ cấp
và bể lắng thứ cấp. Bể lắng sơ cấp được đặt trước công trình xử
lý sinh học dùng để giữ lại các chất hữu cơ không tan trong
nước thải trước khi cho nước thải vào các bể xử lý sinh học và
loại bỏ các chất rắn có khả năng lắng và các chất nổi. Nếu được
thiết kế chính xác, bể lắng sơ cấp có thể loại bỏ 50 - 70% chất
rắn lơ lửng, 25 - 40% BOD của nước thải.
3. Lọc được ứng dụng để tách các tạp chất phân tán có kích thước
nhỏ ra khỏi nước thải mà các bể lắng không thể loại chúng được.
Đây là quá trình tách các hạt rắn ra khỏi pha lỏng hoặc pha khí
bằng cách cho dòng khí hoặc lỏng có chứa hạt chất rắn chảy qua
lớp ngăn xốp, khi đó các hạt rắn sẽ bị giữ lại. Quá trình lọc có
thể xảy ra dưới tác dụng của áp suất thủy tĩnh trong cột chất
lỏng hoặc áp suất cao trước vách ngăn hay áp suất thấp sau vách
ngăn.
FURTHER READING
Task 1: Match the headings with the descriptions of stages in water
treatment process

1. COAGULATION a. The process of making air become mixed

AND with water.
FLOCCULATION b. The purpose of this stage is to remove
debris. Suspended particles remain in the
water.
2. FILTRATION
c. The process of depositing solid materials at
the bottom of a liquid.
3. SCREENING
d. Drinking water is transported through pipes
to individual consumers.
4. AERATION e. This removes the solids remaining in the
water and removes many but not all
microorganisms.
5. DISINFECTION
f. Chemicals are added to coagulate
suspended particles. Then, water is agitated
6. DISTRIBUTION so coagulated material forms bigger
particles. If not removed, suspended
83
 particles can affect taste and color or
interfere with water disinfection.
7. SEDIMENTATION
g. This stage is used to kill remaining
microbes. In the United States, the
disinfectant is often a chlorine-containing
chemical. In Europe it is often ozone.
Because ozone dissociates into oxygen,
another disinfectant is needed to maintain
disinfection as water is transported to
consumers. Historically the beginning of
water disinfection marked the end of
typhoid and cholera epidemics.

Task 2: Summarize the article about waste water treatment using tables
or charts
Wastewater Treatment
Wastewater treatment refers to the process of removing pollutants
from water previously employed for industrial, agricultural, or municipal
uses. The techniques used to remove the pollutants present in wastewater
can be broken into biological, chemical, physical and energetic. These
different techniques are applied through the many stages of wastewater
treatment.

84
 Primary treatment usually includes the removal of large solids
from the wastewater via physical settling or filtration. The first step in
primary treatment is screening.
Secondary treatment typically removes the smaller solids and
particles remaining in the wastewater through fine filtration aided by the
use of membranes or through the use of microbes, which utilize organics
as an energy source. Energetic techniques may also be employed in
tandem with biological techniques in the secondary phase to break up the
size of particles thus increasing their surface area and rate of
consumption by the microbes present. A common first step in the
secondary treatment process is to send the waste to an aeration tank.
Tertiary treatment involves the disinfection of the wastewater
through chemical or energetic means. Increasing the number of steps in a
wastewater treatment process may insure higher quality of effluent;
however employing additional technologies may incur increased costs of
construction, operation and maintenance.
Primary treatment
Screening is the first technique employed in primary treatment,
which is the first step in the wastewater treatment process.
This step removes all sorts of refuse that has arrived with the
wastewater such as plastic, branches, rags and metals. The screening
process is used primarily to prevent the clogging and interference of the
following wastewater treatment processes.
Screens are considered coarse if their opening are larger than 6
mm, fine if their openings are between 1.5 and 6 mm and very fine if
their openings are between 0.2 and 1.5 mm.

This type of screen, called a bar screen, removes debris from

wastewater.

85
 Screens are cleaned manually if the object caught is larger and
mechanically if finer particles are caught. The angle of the screen may
also be varied to affect the efficiency of filtration.
In order to remove coarse solids, numerous types of detritus tanks,
grinders and cyclonic inertial separation are utilized, including
a comminutor and a grit chamber. The type of grit removal separation
depends upon the characteristics of the grit itself.
A comminutor, also known as the grinding pump,
houses a rotating cutting screen. This cutting screen
shreds any large chunks of organic matter in the
wastewater into smaller pieces. This makes it easier for
the microorganisms to use the organic matter as food
and prevents the large chunks from harming the internal
workings of the treatment plant.
A grit chamber allows pieces of rock,
metal, bone and even egg shells, which are denser
than organic materials, to settle out of the waste
stream. Removal of grit prevents damage to
machinery through abrasion or clogging.

The last step in primary treatment is sedimentation,

which occurs in the primary clarifier.

Sedimentation simply
entails the physical settling of
matter, due to its density,
buoyancy and the force of
gravity. Certain chemicals
known as coagulants and
flocculants are often used to
expedite this process by
encouraging aggregation of
particles. Through
sedimentation, the larger
solids are removed in order to
facilitate the efficiency of the
following procedures and also
to reduce the biological
oxygen demand of the water.
86
 The biochemical oxygen demand (BOD) refers to the amount of
oxygen required by the microbes within the wastewater to digest the
matter that they are using for food. By removing these solids early on, the
efficiency of the microbial digestion at later stages is increased.
Secondary treatment
Once the wastewater leaves the primary
treatment steps, it enters secondary treatment. The first
step in the secondary treatment process is the aeration
tank.
Bacteria are single celled organisms, which have basic
requirements for existence and reproduce rapidly. Many occupy unique
niches and consume only certain types of food. Many types of bacteria
have been utilized in wastewater processing. If a certain bacterium is
supplied with an environment in which the proper pH, temperature,
micro and macronutrients and oxygen levels are present, it can quickly
and effectively break pollutants present in wastewater down into less
harmful components.
The types of bacteria utilized in wastewater
processing can be categorized based upon their
necessary or intolerance of oxygen to survive. Those
bacteria that require oxygen to convert food into
energy are called aerobic; those that will perish in the
presence of oxygen are anaerobic; and finally
facultative anaerobes may thrive in either the
presence or absence of oxygen. Typically aerobes,
which can degrade pollutants 10-100 times faster
than anaerobes, are utilized most frequently.
Increases in temperature and pollutant food source
have shown to increase the rate of degradation, but if
all elements necessary for conversion of food to
energy are not in balance, the microbial degradation
will be thwarted.
The wastewater is then passed
through a secondary clarifier, which
performs sedimentation again. This is
described earlier and occurs in primary
treatment as well.

87
 The disinfection of wastewater through the use
of chemicals such as chlorine typically acts as the
final step in wastewater treatment. Disinfection seeks
to remove harmful organics and pathogens causing
cholera, polio, typhoid, hepatitis and a number of
other bacterial, viral and parasitic diseases from the
water.
Due to security concerns, some wastewater treatment facilities are
using sodium hypochlorite to eliminate the need for chlorine. Sodium
hypochlorite is more expensive than liquid chlorine but is also safer.
Although chlorine is considered the tried and true solution to reducing
pathogens in contaminated water, the method of disinfection, such as UV
disinfection, must fit the type of pathogen the wastewater harbors - to be
truly effective.
Through disinfection, a significant portion of the pathogens are
inactivated. However, it is difficult to identify individual pathogens
within wastewater, therefore indicator pathogens are used. In
wastewater, fecal coliform acts as the indicator pathogen, but there has
been discussion of using E. coli or total coliform – the indicator for
potable water – to check wastewater.
Coagulation and Flocculation
Coagulants and
flocculants are chemicals
used to precipitate insoluble
substances. The purpose of
coagulation and flocculation
is to cause small pollutant
particles such as metals to
aggregate and form large
enough floc so that they can be separated from the wastewater through
sedimentation.
There are three main types of coagulants that are used to overcome
the repulsive forces of particles, thus causing them to aggregate.
Electrolytes, organic polymers and synthetic polyelectrolites are added to
wastewater and then flocculation tanks mix the water to promote flocs
and subsequent physical separation.
Rate of flocculation is dependent upon many factors including
concentration of particles, particle contact and range of particle sizes.

88
Coagulation targets dissolved ions such as metal and radionuclides. Some
difficulties with this technology include the frequent need to adjust pH
levels, the creation of toxic sludge that must be eventually mitigated, and
the difficulty that results in trying to address the chemical nature of
multiple compounds. This technology has been used consistently in the
electronics and electroplating industry as well as for applications in
groundwater treatment.
Membrane filtration

The three main types of membrane-based filtration technologies

include reverse-osmosis, nanofiltration, and ultrafiltration. Although
categorized as different technologies, the three types of membrane
filtration have a great deal in common. All three act as membranes
created by coating a thin layer of a very porous polymer, or plastic, onto
a backing material. The end result is the finest form of filtration presently
known, with reverse-osmosis being the smallest, nanofiltration being a
slight step larger and ultrafiltration being a bit larger again.
The pore sizes are typically measured in angstroms (one billionth
of a meter) and thus are extremely tiny. These membrane technologies
offer a host of advantages over traditional filtration. Due to the fine pore
space and indiscrimination of influents of these membrane filtration
systems, a very high quality effluent emerges. Additionally, membrane
technologies take up only a fraction of the space needed for other tertiary
treatment systems. The disadvantage of having extremely fine pores
means that clogging is a frequent and costly problem with membrane
filtration technologies.
Constructed wetlands
Scientists have long
recognized the abilities of
wetlands to purify water.
Through the correct sequencing
of base media, plant species and
microbe species, constructed
wetlands can successfully
reduce nitrogen content, filter
out solids and reduce the
presence of heavy metals.
The type and amount of pollutant removed depends upon the
species and oxygen affinity of the organisms present in the wetland.
89
Wetlands utilize physical and chemical processes to clean wastewater
and typically serve as the secondary and tertiary steps.
Although constructed wetlands tend to take up a great deal of
space, they require less investment of time and money than traditional
waste treatment procedures. Ultimately, constructed wetlands are a cost-
effective and environmentally-benign method of wastewater processing.
(Mountain Empire Community College, n.d.a)

90
 8 SOLID WASTE

Look at the pictures below and answer the following questions in groups
1 2

3 4

5 6

91
 1. What is solid waste? How does it differ from sewage or
wastewater?
2. Is solid waste a serious problem?
3. How many kinds of solid waste do you know? How many
sources of solid waste do you know?
4. What problems does solid waste cause to human life nowadays?

READING
Task 1: Identify types of waste

1 2

3 4

5 6

92
 7 8

Task 2: Matching the headings with the appropriate descriptions of

different types of solid waste
Garbage Domestic/Residential waste
Commercial waste Dead animals
Rubbish Construction and demolition waste
Bulky waste Ashes
Sewage waste Industrial waste
Street sweepings Institutional waste
Hazardous waste

Solid waste is defined as discarded solid fraction produced from

domestic, commercial, trade, industrial, agricultural, institutional, mining
activities and public services.
The solid waste can be classified in the Manual on Municipal Solid
Waste Management, published by Government of India publication as
follows:
SOURCE –BASED CLASSIFICATION
(i) _________________: This type of waste is originated
from single or multifamily household units. These wastes are generated
from the household activities such as cooking (ashes), cleaning (dust),
repairs (residues), redecoration, empty containers, used packets, old
clothes, books, papers, broken glass, plastic items as well as broken and
useless furniture.

93
 (ii) _________________: This category includes solid wastes
that originate in offices, wholesale and retail markets, restaurants, hotels,
warehouses and other commercial establishments.
(iii) _________________: These are those wastes generated
from institutions such as schools, colleges, universities, hospitals and
research institutes. Some of these wastes (like hospitals) may be
hazardous.
CHARACTERISTIC-BASED CLASSIFICATION
(i) ________________: This term is applied to animal and
vegetable wastes generated from the handling, storage, sale, preparation,
cooking and serving of food. Such wastes contain putrescible (easily and
quickly biodegraded with bad smell) organic matter. This attracts rats,
flies, mosquito and other vermin, that is why it requires immediate
attention.
(ii) ________________: It is a general term applied to solid
wastes originating in households, commercial establishments and
institutions excluding garbage and ashes.
(iii) ________________: These are the residues from the
burning of wood, coal, charcoal, coke and other combustible matter for
cooking and heating in houses institutions and small industries. When
produced in large quantities in thermal power plants (fly ash) they are
known as industrial wastes. They consist of fine powdery residue, cinders
and clinkers often mixed with small pieces of metal and glass.
(iv) _________________: are large household wastes that
cannot be accommodated in the normal storage containers of the
household and thus they require special collection.
(v) __________________: The waste that is collected from
streets, walkways, parks etc. It includes mainly dust, dirt, plastic bags
(thin), dry leaves, useless papers, cardboard, rags, tyres, vegetable matter,
etc.
(vi) __________________: This term refer to animal corpses.
It does not include the animal parts from slaughter houses which are
regarded as industrial waste. There are two types of this waste, large and
small. The smaller ones like dogs, cats, rabbits, rats, etc., are either
consumed by the other animals or can be easily lifted and disposed. The
large ones like cows, horses, camels, etc. require special and immediate
attention as traffic is affected and they emit foul smell.

94
 (vii) ____________________: These are the wastes generated
by the residue of the construction, refurbishment, repair and demolition
of houses, commercial buildings and other structures.
(viii) ____________________: The discarded solid material of
manufacturing processes and industrial operations comes in this category.
There is a vast range of substances that are unique for each industry so
they are considered separately from municipal wastes.
(ix) ___________________: This waste defined as wastes of
industrial, institutional or consumer origin that, because of their physical,
chemical or biological characteristics, are potentially dangerous to human
beings and the environment. In some cases, the active agents may be
liquid or gaseous; they are classified as solid waste because they are
confined in solid containers. Typical examples are solvents, paints and
pesticides whose empty containers are frequently mixed with municipal
wastes and become part of the urban waste stream.
(x) __________________: The solid by-products of sewage
treatment are classified as sewage wastes. They are mostly organic and
produced from the treatment of organic sludge from both the raw and
treated sewage. The inorganic fraction of raw sewage such as grit is
separated at the preliminary stage of treatment, but because it entrains
putrescible organic matter that may contain disease-producing bacteria
(pathogens), it must be buried or disposed of quickly.
(Adapted from Gaur, 2007, pp.87-111)

Task 3: Complete the table below with the correct types of solid waste
Types of solid waste Examples

…………………………………. 1. animal and vegetable wastes

generated from the handling,
storage, sale, preparation,
cooking and serving of food.
………………………………….. 2. sludge left from industrial
waste water treatment processes

…………………………………. 3. wastes originating in offices,

wholesale and retail markets,

95
 restaurants, hotels, warehouses
4. waste paper, used pens and old
………………………………….
folders from schools, colleges,
universities, hospitals and
research institutes

………………………………… 5. empty containers of pesticides

and herbicides, pathological
wastes from hospitals or
radioactive waste
………………………………… 6. leaves, wood branches, plastic
bags, bottles and so on on the
streets
…………………………………. 7. wastes generated from the
burning of wood, coal, charcoal
and other combustible matter
8. sand, stone or concrete left on
………………………………….
construction sites or after
house repair

Task 4: Answer the following questions in pairs

1. What is solid waste?
2. How many types of solid waste, based on sources, are there?
3. How many types of solid waste, based on characteristic, are
there?
4. In your opinion, which types are the most difficult to be treated?
Why?
5. In your opinion, which types affect human life most? Why?
6. Which types are the most easily found in your neighborhood?

VOCABULARY
Fill in the gaps in the following text with correct words
Toxic waste is waste m_______ that can cause death, injury or
birth defects to living creatures. It spreads quite easily and can c_______
lakes, rivers and the atmosphere. The term is often used interchangeably
96
with “hazardous waste”, or d______ material that can pose a long-term
risk to health or e________.
Hazardous wastes are poisonous b_______ of manufacturing,
farming, city septic systems, construction, automotive garages,
laboratories, hospitals and other industries. The waste may be liquid,
solid, or s_______ and contain chemicals, heavy metals, radiation,
dangerous p________, or other toxins. Even households generate
hazardous waste from items such as batteries, used computer equipment
and leftover paints or p________.
In the United States, the Environmental Protection Agency (EPA)
and the state departments oversee the rules that r________ hazardous
waste. The EPA requires that toxic waste be handled with special
precautions and be d_______ of in designated facilities around the
country. Also, many cities in the United States have collection days
where household toxic waste is gathered. Some materials that may not be
accepted at regular l_____ are ammunition, commercially generated
waste, explosives/shock sensitive items, hypodermic needles/syringes,
medical waste, radioactive materials and smoke detectors.
(Adapted from wikipedia, 2014b)

TRANSLATION
Task 1: Translate the following passage into Vietnamese
Hazardous waste is waste that poses substantial or potential
threats to public health or the environment. In the United States, the
treatment, storage and disposal of hazardous waste is regulated under
the Resource Conservation and Recovery Act (RCRA). Hazardous
wastes are defined under RCRA where they are divided into two major
categories: characteristic wastes and listed wastes.
Hazardous wastes are materials that are known or tested to exhibit
one or more of the following four hazardous traits: ignitability
(i.e., flammable), reactivity, corrosivity, toxicity.
The requirements of RCRA apply to all the companies that
generate hazardous waste as well as those companies that store or dispose
of hazardous waste in the United States. Many types of businesses
generate hazardous waste. For example, dry cleaners, automobile repair
shops, hospitals, exterminators and photo processing centers may all
generate hazardous waste. Some hazardous waste generators are larger

97
companies such as chemical manufacturers, electroplating companies
and oil refineries.
These wastes may be found in different physical states such as
gaseous, liquids or solids. A hazardous waste is a special type of waste
because it cannot be disposed of by common means like other by-
products of our everyday lives. Depending on the physical state of the
waste, treatment and solidification processes might be required.
(Pinwaste, 2014)
Task 2: Translate the following passage into English
Chất thải là những vật và chất mà người dùng không còn muốn sử
dụng và thải ra. Tuy nhiên, trong một số ngữ cảnh, nó có thể không có ý
nghĩa với người này nhưng có ích cho người khác. Trong cuộc sống, chất
thải được hình dung là những chất không còn được sử dụng cùng với
những chất độc xuất ra từ chúng.
Quản lý rác thải là hành động thu gom, phân loại và xử lý các loại
rác thải của con người. Hoạt động này nhằm làm giảm các ảnh hưởng
xấu của rác thải vào môi trường và xã hội.
Rác liên quan trực tiếp tới sự phát triển của con người cả về công
nghệ và xã hội. Cấu tạo của các loại rác biến đổi qua thời gian và nơi
chốn cùng với quá trình phát triển và đổi mới có tính chất công nghiệp
đang trực tiếp ảnh hưởng tới nguồn phế liệu, ví dụ như nhựa và công
nghệ hạt nhân. Một số thành phần của rác có giá trị kinh tế đã được tái
chế một cách hoàn hảo.
Rác thải sinh hoạt là các chất rắn bị loại ra trong quá trình sống,
sinh hoạt, hoạt động, sản xuất của con người và động vật. Rác phát sinh
từ các hộ gia đình, khu công cộng, khu thương mại, khu xây dựng, bệnh
viện, khu xử lý chất thải… Trong đó, rác sinh hoạt chiếm tỷ lệ cao nhất.
Số lượng, thành phần chất lượng rác thải tại từng quốc gia, khu vực rất
khác nhau, phụ thuộc vào trình độ phát triển kinh tế, khoa học, kỹ thuật.
Bất kỳ một hoạt động sống của con người tại nhà, công sở, trên đường đi,
tại nơi công cộng,…, đều sinh ra một lượng rác đáng kể. Thành phần chủ
yếu của chúng là chất hữu cơ và rất dễ gây ô nhiễm trở lại cho môi
trường sống.

FURTHER READING
Any useless, unwanted discarded material that is not a liquid or gas
is referred as solid waste or refuse. For example, it may be yesterday’s
98
newspaper, junk mail, today’s meal scraps, pieces of bread, waste rice,
racked leaves, dust, grass clippings, broken furniture, abandoned
materials, animal manure, sewage sludge, industrial refuse or street
sweepings, etc.
CLASSIFICATION
Typical classification of solid waste was suggested by Hosetti and
Kumar (1998) and it is as follows.
1. Garbage: putrecible wastes from food, slaughterhouses, canning
and freezing industries.
2. Rubbish: non-putrecible wastes either combustible or non-
combustible. These include wood, paper, rubber, leather and garden
wastes as comustible wastes whereas the non-combustible wastes include
glass, metal, ceramics, stones and soil.
3. Ashes: residues of combustion, solid products after heating and
cooking or incineration by the municipal, industrial, hospital and
apartments areas.
4. Large wastes: demolition and construction wastes, automobiles,
furniture, refrigerators and other home appliances, trees, fires, etc.
5. Dead animals: household pets, birds, rodents, zoo animals, and
anatomical and pathological tissues from hospitals.
6. Sewage sludges: these include screening wastes, settled solids
and sludges.
7. Industrial wastes: chemicals, paints, sand and explosives.
8. Mining wastes: tailings, slug ropes, culm piles at mine areas.
9. Agricultural wastes: farm animal manure, crop residues and
others.
Traditionally these wastes are categorized into the following five types.
1. Residential: It refers to wastes generated mainly from dwelling,
apartments and consisted of leftover food scrapes, vegetables, peeled
material, plastics, woodpieces, clothes and ashes.
2. Commercial: This mainly consists of grocery materials, leftover
food, glasses, metals and ashes generated from stores, hotels, markets,
shops and medical facilities.
3. Institutional: The wastes generated from schools, colleges and
offices include paper, plastics and glasses.
99
 4. Municipal: This includes dust, leaf litter, building debris and
treatment plant sediments. These arise from various activities like
demolition, construction, street cleaning, land scraping, etc.
5. Agricultural: This mainly includes spoiled food grains,
vegetables, grass, litter, etc. generated from fields and farms.
Classification of Solid Wastes Based on Types
These wastes may have reuse values in some other places, but these
are of no value to the possessor who wishes to dispose them. The
knowledge about sources of solid wastes along with the information of
the composition and rate of generation will help in the process of design
and operation of the functional elements associated with the disposal and
management of solid wastes. Therefore, it is important to define various
types of solid waste that aregenerated from various sources (Pheleps et
al., 1995).
Refuse: This is all putrecible and non-putrecible waste except body
wastes. It includes all types of rubbish and garbage.
Rubbish: This refers to that portion of the refuse, which is non-
putrecible solid waste such as packaging materials.
Garbage: This refers to that portion of the refuse, which is
putrecible component of solid waste. These are produced during cooking
and storage of meet, fruits and vegetables.
Bulky wastes: These include household wastes, which cannot be
accommodated in the normal storage containers and need a special
collection mechanism. These include household appliances such as
refrigerators, washing machine, furniture, vehicle parts, tyres, trees,
wood branches etc.
Street wastes: This includes wastes collected from streets,
walkways, parks, playgrounds. Examples of this type are paper,
cardboard, plastics, leaves and other vegetable matter in large quantities.
Dead animals: These include dead animals which die naturally or
are accidentally killed on the road. This category does not include
carcasses and animal parts from slaughterhouses, which may be regarded
as commercial or industrial components. Many times as in India, large
animals if died and are not lifted on right time may pose a threat to public
health through attracting flies, produce bad odour and create an
unhygienic scene.

100
 Hazardous wastes: Hazardous wastes are those produced in the
industries, institutes, hospitals and laboratories. These are dangerous to
the living organisms immediately or in the long run to the environment in
which they are disposed. The hazard may be due to their physical,
chemical, biological and radioactive characteristics like, ignitibility,
corrosivity, reactivity and toxicity. In some cases, various chemicals and
their mixtures, such as pesticides, solvents, acids and bases, act as
hazardous wastes. Certain hazardous wastes may cause explosions in the
incinerators and fires at the landfill sites. Other hazardous waste includes
pathological wastes from hospitals and radioactive wastes, which require
special handling. A good management practice should ensure that
hazardous wastes are stored, collected, transported and disposed
separately after suitable treatment.
Sewage sludge: The sewage treatment plants produce huge
amounts of sludge during primary and secondary phase of treatment,
these are sticky and rich in pathogens require proper treatment. These are
both inorganic and organic. The bulk of dewatered and digested sludge
can be used as organic fertilizer or it may be burnt to produce energy.
MISMANAGEMENT AND EFFECTS ON THE
ENVIRONMENT
Solid waste management is an important facet of environmental
hygiene and it needs to be integrated with total environmental planning
(WHO Expert Committee, 1971). Its storage, collection, transport,
treatment and disposal can lead to short term risks. In the long run there
may be dangers arising particularly from the chemical pollution of water
supplies.
Javeen Rao (1994) said that the problems connected with refuse
storage in buildings were insects, rats, fire and odor. These problems are
also associated with other problems of human health and aquatic systems.
Apart from the disease for which insects and rats are the carriers,
the handling of it causes illness to workers. A survey in India conducted
by CEPHERI, 1971 (Central Public Health Engineering Institute) showed
that in Bhopal city up to half of the sample of refuse in the slum areas
contained roundworm ova. The accident rate among workers is also high
as a result of lifting heavy load of waste and dealing with mechanical
equipments.
Atmospheric pollution
When refuse is burnt in an open area, a dense smoke often covers
the site and neighboring land. Old-fashioned incinerators without air
101
pollution control equipment are little better than open burning. Apart
from particulate matter that constitutes smoke, the gaseous discharges
from the incomplete combustion may include SO2, NOx and various
gases. If PVC is a constituent of the refuse, the gases may include
hydrogen chloride. In addition to pest nuisance and health hazards, the
solid wastes also cause air pollution. Burning of solid wastes in open
dumps or use of improperly designed incinerators produce excessive
pollution. Studies revealed that emission from the uncontrolled burning
leads to the production of particulate matter, sulfur oxides, nitrogen
oxides, carbon monoxides, lead and mercury. Discharge of arsenic and
cadmium are to be controlled. Polychlorinated dibenzofurans are called
as dioxins and furans. These are of more concern about their toxicity as
carcinogens and mutagens.
Visual pollution
The aesthetic feeling is offended by the unsightfullness of piles of
wastes on the roadsides.This situation was being made worst by the
presence of scavenging animals, especially in the third world countries.
The scavenging animals search their food in the waste and spread it
around places. Similarly the rag pickers in India also create such
unhygienic scene while collecting recyclables. This creates an ugly
situation and under such conditions apart from cleaning the waste, there
is a need to educate the public about environmental health.
Undesirable noise and traffic sound is also produced while
operating the landfills and incinerators. This is due to the movement of
vehicles and large machines.
Tourism/Ethics/Recreation
Uncontrolled refuse and sanitary tips in full public view are
eyesores. If tourism is important in such cases esthetic nuisance may
reduce the number of visitors with the resultant economic loss. There can
be depreciation of the value of property nearer to a garbage area or
incinerator spillage from vehicle. In addition to this, bad smell, increase
of flies, rats, wind blown dust, paper and plastics all of which are harmful
to the locality. On the other hand, refuse can be used in a well-planned
controlled way to improve low lying and derelict or aridlands and
property values may then increase in the vicinity.
Water pollution
When the rain run-off joins the surface water sources there is an
inevitably pollution due to suspended solid particles. Organic matters
exert high oxygen demand and pathogen load can create a health risk to
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downstream users. Unless the water table is not high or underlying rock
is not fissured, the ground water will be hardly affected. Dumps should
not be close to shallow wells. A distance of 12 km is suggested. On the
other hand, avoidance ofground water pollution is of paramount
importance in the dumping of refuse.
Other effects
Insects
A common transmission route of bacillary dysentery, amoebic
dysentery and other diarrhoeal diseases are from human fecal matter
spread through flies to food or water, thence to man. Flies thrive on food
wastes and are plenty in USA. 90% of house flies in the cities of USA
breed on open garbage. If night soil and unprotected latrines are close to
refuse dumps, the disease routes are widespread, as the flies can fly upto
10 km. Refuse dumped on ground resulted in the infestation with fly eggs
and larvae upto 50 mm below the surface.The breeding of mosquitoes in
discarded tyres, tins, and jam bottles are reported.
Rats and other vertebrate vectors
The main source of food for rats and other smaller rodents is refuse
and rubbish dumps where they can quickly proliferate and spread to
neighboring houses. The rats become vectors to histoplasmosis, rat bite
fever, salmonellosis, tularemia and trichinosis, etc. Most of the birds of
prey always hover over these dumps and spread the waste to neighboring
areas. In addition to this, the other birds like pigeons, crows seagulls also
sere as vectors.
Fire
Ashes added to combustible refuse pose a great danger at the
source and fire in uncontrolled tips has been known to burn for months or
even years. Usually the fire starts with unsustainable practice of open
dumping of refuse and it can spread accidentally. Occasional fires began
spontaneously from the heat given off by decomposition or by glass on
open dumpacting as a lens for sunlight. Flammable industrial wastes
increase the danger of fire and can convert old tyres into toxic gases
(dioxins and furans).
Odor
While passing through a crowded city in tropical areas, a traveller
may experience bad smell. It is due to the combination of rottening
vegetation and fecal matter and other solid wastes indiscriminately
discarded. When this stink persists all the day and night it causes a major
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environmental nuisance. This bad smell is also due to the release of
hydrogen sulfideduring decomposition.
(Hosetti, 2006, p.1-5)

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 9 SOLID WASTE MANAGEMENT

Match the picture with suitable description

A.

a. transfer trucks

b. out-of-county
landfill

c. private garbage
hauler

d. garbage cart

e. tranfer station

B.
a. door-to-door
collection with
segregation

b. pre-curing of bio
degradable waste

c. vermi-composting

d. recycable waste
segregation

e. secondary
collection

105
 READING
SOLID WASTE MANAGEMENT
Management of solid waste reduces or eliminates adverse impacts
on the environment and human health as well as supports economic
development and improved quality of life. A number of processes are
involved in effectively managing waste for a municipality. These include
monitoring, collection, transport, processing, recycling and disposal.
Reduce, Reuse, Recycle
Waste reduction and reuse
Waste reduction and reuse of products are both methods of waste
prevention. They eliminate the production of waste at the source of usual
generation and reduce the demands for large scale treatment and disposal
facilities. Methods of waste reduction include manufacturing products
with less packaging; encouraging customers to bring their own reusable
bags for packaging; encouraging the public to choose reusable products
such as cloth napkins reusable plastic and glass containers; backyard
composting; and sharing and donating any unwanted items rather than
discarding them.
Recycling
Recycling refers to the removal of items from the waste stream to
be used as raw materials in the manufacture of new products. Thus from
this definition, recycling occurs in three phases: firstly the waste is sorted
and the recyclables are collected; secondly, the recyclables are used to
create materials which are at last used in the production of newproducts.
The sorting of recyclables may be done at the source (i.e. within the
household or office) for selective collection by the municipality or to be
dropped off by the waste producer at a recycling centres. Another option
is to mix the recyclables with the general waste stream for collection, and
then sorting and recovering the recyclable materials can be performed by
the municipality at a suitable site. Recycling reduces reliance on natural
resources, landfills and incinerators.
All of the methods of solid waste management mentioned require
public participation. In order to get the public on-board, training and
educational programmes need to be undertaken to educate the public
about their role in the process. Also the government may need to regulate
the types and amount of packaging used by manufacturers and make the
reuse of shopping bags mandatory.
(Caribbean Youth Environment Network, n.d.)
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Task 1: Decide whether the following statements are TRUE or FALSE
1. Effective solid waste management not only helps diminish
adverse impacts on the environment but also improve quality of
human life.
2. Promoting a product’s lifetime is a method of reducing solid
waste.
3. Methods of waste prevention include waste reduction, reusing
and recycling.
4. Manufacturing products with less packaging, encouraging
customers to bring their own shopping bags, encouraging the
public to choose reusable products, backyard composting as well
as sharing and donating unwanted items are among methods of
waste recycling.
5. Reduction is believed to conserve natural resources by reducing
the demand for raw materials.
6. The recyclables may be separated at the source by residents or at
a suitable site by the municipality.
7. Reusing is the process of separating, collecting, processing and
ultimately using a material that would have been discarded.
8. The public should be educated to define their role in the
processes of solid waste management.

Treatment & Disposal

Waste treatment techniques seek
to transform the waste into a form that
is more manageable, reduce the
volume or the toxicity of the waste
thus making the waste easier to
dispose of. Treatment methods are
selected based on the composition,
quantity and form of the waste
material. Some waste treatment
methods being used today include
subjecting the waste to extremely high
temperatures, dumping on land or land

107
filling and use of biological processes to treat the waste. It should be
noted that treatment and disposal options are chosen as a last resort to the
previously mentioned management strategies: reducing, reusing and
recycling of waste.
Thermal treatment
This refers to the processes that involve the use of heat to treat
waste. Listed below are descriptions of some commonly utilized thermal
treatment processes.
Incineration
Incineration is the most common thermal treatment process. This is
the combustion of waste in the presence of oxygen. After incineration,
the wastes are converted to carbon dioxide, water vapour and ash. This
method may be used as a means of recovering energy to be used in
heating or the supply of electricity. In addition to supplying energy,
incineration technologies have the advantage of reducing the volume of
the waste, rendering it harmless, reducing transportation costs and
reducing the production of the greenhouse gas methane.
Pyrolysis and Gasification
Pyrolysis and gasification are similar processes. They both
decompose organic waste by exposing it to high temperatures and low
amounts of oxygen. Gasification uses a low oxygen environment while
pyrolysis allows no oxygen. These techniques use heat and an oxygen
starved environment to convert biomass into other forms. A mixture of
combustible and non-combustible gases as well as pyroligenous liquid is
produced by these processes. All of these products have a high heat value
and can be utilised. Gasification is advantageous since it allows for the
incineration of waste with energy recovery and without the air pollution
that is characteristic of other incineration methods.
Open burning
Open burning is the burning of unwanted materials in a manner that
causes smoke and other emissions to be released directly into the air
without passing through a chimney or stack. This includes the burning of
outdoor piles, burning in a burn barrel and the use of incinerators which
have no pollution control devices and as such release the gaseous by-
products directly into the atmosphere.
Open burning has many negative effects on both human health and
the environment. This uncontrolled burning of garbage releases many
pollutants into the atmosphere. These include dioxins, particulate matter,
108
polycyclic aromatic compounds, volatile organic compounds, carbon
monoxide, hexachlorobenzene and ash. All of these chemicals pose
serious risks to human health. They can have adverse effects on
reproduction, development, disrupt the hormonal systems or even cause
neurological symptoms, cancer and respiratory problems such as asthma
or bronchitis. The harmful effects of open burning are also felt by the
environment. This process releases acidic gases, nitrogen oxides and
carbon oxides, contributing to acid rain, ozone depletion, smog and
global warming.
Dumps and Landfills
Sanitary landfills
Sanitary Landfills
are designed to
greatly reduce or
eliminate the risks
that waste disposal
may pose to the
public health and
environmental
quality. They are
usually placed in
areas where land
features act as
natural buffers
between the landfill and the environment. For example the area may be
comprised of clay soil which is fairly impermeable due to its tightly
packed particles, or the area may be characterised by a low water table
and an absence of surface water bodies thus preventing the threat of
water contamination.
In addition to the strategic placement of the landfill, other
protective measures are incorporated into its design. The bottom and
sides of landfills are lined with layers of clay or plastic to keep the liquid
waste, known as leachate, from escaping into the soil. The leachate is
collected and pumped to the surface for treatment. Boreholes or
monitoring wells are dug in the vicinity of the landfill to monitor
groundwater quality.
A landfill is divided into a series of individual cells and only a few
cells of the site are filled with trash at any one time. This minimizes
exposure to wind and rain. The dailywaste is spread and compacted to

109
reduce the volume, a cover is then applied to reduce odours and keep out
pests. When the landfill has reached its capacity, it is capped with an
impermeable seal which is typically composed of clay soil.
Some sanitary landfills are used to recover energy. The natural
anaerobic decomposition of the waste in the landfill produces landfill
gases which include carbon dioxide, methane and traces of other gases.
Methane can be used as an energy source to produce heat or electricity.
Thus some landfills are fitted with landfill gas collection (LFG) systems
to capitalise on the methane being produced. The process of generating
gas is very slow, for the energy recovery system to be successful there
needs to be large volumes of wastes.
These landfills present the least environmental as well as health
risk and the records can be a good source of information for future use in
waste management. However, the cost of establishing these sanitary
landfills is high when compared to the other land disposal methods.
Controlled dumps
Controlled dumps are disposal sites which comply with most of the
requirements for a sanitary landfill but usually have one deficiency. They
may have a planned capacity but no cell planning. There may be partial
leachate management, partial or no gas management, regular cover,
compaction in some cases, basic record keeping and they are fenced or
enclosed. These dumps have a reduced risk of environmental
contamination, the initial costs are low and the operational costs are
moderate. While there is controlled access and use, they are still
accessible by scavengers and so there is some recovery of materials
through this practice.
Bioreactor landfills
Recent technological advances have lead to the introduction of the
Bioreactor landfill. The Bioreactor landfills use enhanced
microbiological processes to accelerate the decomposition of waste. The
main controlling factor is the constant addition of liquid to maintain
optimum moisture for microbial digestion. This liquid is usually added
by re-circulating the landfill leachate. In cases where leachate is not
enough, water or other liquid waste such as sewage sludge can be used.
The landfill may use either anaerobic or aerobic microbial digestion or it
may be designed to combine the two. These enhanced microbial
processes have the advantage of rapidly reducing the volume of the
waste, creating more space for additional waste. They also maximise the
production and capture of methane for energy recovery systems and they
110
reduce the costs associated with leachate management. For Bioreactor
landfills to be successful, the waste should be comprised predominantly
of organic matter and should be produced in large volumes.
Biological waste treatment
Composting
Composting is the controlled aerobic decomposition of organic
matter by the action of micro organisms and small invertebrates. There
are a number of composting techniques being used today. These include:
in vessel composting, windrow composting, vermin composting and
static pile composting. The process is controlled by making the
environmental conditions optimum for the waste decomposers to thrive.
The rate of compost formation is controlled by the composition and
constituents of the materials (i.e.their Carbon/Nitrogen (C/N) ratio), the
temperature, the moisture content and the amount of air.
Anaerobic digestion
Anaerobic digestion like composting uses biological processes to
decompose organic waste. However, where composting can use a variety
of microbes and must have air, anaerobic digestion uses bacteria and an
oxygen free environment to decompose the waste. Aerobic respiration,
typical of composting, results in the formation of carbon dioxide and
water, while the anaerobic respiration results in the formation of carbon
dioxide and methane. In addition to generating the humus which is used
as a soil enhancer, anaerobic digestion is also used as a method of
producing biogas which can be used to generate electricity.
Optimal conditions for the process require nutrients such as
nitrogen, phosphorous and potassium. It is required that the pH be
maintained around 7 and the alkalinity be appropriate to buffer pH
changes while temperature should also be controlled.
Integrated Solid Waste Management
Integrated Solid Waste Management (ISWM) takes an overall
approach to creating sustainable systems that are economically
affordable, socially acceptable and environmentally effective. An
integrated solid waste management system involves the use of a range of
different treatment methods and key to the functioning of such a system
is the collection and sorting of the waste. It is important to note that no
one single treatment method can manage all the waste materials in an
environmentally effective way. Thus all of the available treatment and
disposal options must be evaluated equally and the best combination of
111
the available options suited to the particular community chosen. Effective
management schemes therefore need to operate in ways which best meet
current social, economic and environmental conditions of the
municipality.
(Caribbean Youth Environment Network, n.d.)

Task 2: Match the methods and their appropriate characteristics

Treatment Methods Characteristics
a. This method is to burn wastes without
1. Incineration
any pollution control devices.
b. In this disposal method, leachate and
2. Pyrolysis & Gasification harmful gases can escape into the land
or environment.
c. This employed the organic matter
3. Open burning digestion of microorganisms and small
decomposers to form compost.
d. This is the process of burning wastes
4. Sanitary landfill with the presence of oxygen; it can be
employed in producing electricity.
e. In these approaches, organic matters
5. Controlled dumps are decomposed by high temperature
and low amount of oxygen.
f. This disposal process will enhance
6. Bioreactor landfill microbiological processes to digest the
wastes faster.
g. In this biological method, solid wastes
are decomposed by microorganisms
7. Composting
and small decomposers with little or
no oxygen.
h. This method requires the construction
8. Anaerobic digestion of a disposal site with a few cells
inside.

112
Task 3: Work in pairs and discuss the following questions
1. How does open burning affect the environment?
2. What kind of solid wastes are mainly treated in pyrolysis and
gasification?
3. Why are sanitary landfills mostly built in the regions where the
land can act as natural buffers?
4. How is a sanitary landfill constructed?
5. What are the advantages and disadvantages of sanitary landfill
and controlled dumps?
6. What methods employ microorganisms and small decomposers?
7. What are the differences between composting and anaerobic
digestion?
8. Why should people combine different methods in treating solid
wastes?
VOCABULARY
Fill in the gaps with suitable words in the box
combustion organic emissions industry
landfills combusted incineration generated
forests inorganic transportation materials

113
 Source reduction, reuse, recycling, composting and energy
recovery are all examples of resource conservation. Resource
conservation avoids GHG (greenhouse gases)__(1)___ from common
waste management pathways, including:
 Emissions from ___(2)____. Waste incineration produces
emissions of CO2 and nitrous oxide, a GHG that is 310 times as
potent as CO2.
 Emissions from ___(3)____. Transporting waste to disposal
sites produces GHG emissions from the combustion of the fuel used
in the equipment.
 Emissions from ___(4)____. Waste in landfills decomposes
anaerobically and produces methane, a GHG that is 21 times as
potent as CO2.
In terms of climate benefits, reducing and reusing ___(5)___ offers
the best approaches to reduce GHGs. Because no waste is ___(6)____,
source reduction and reuse avoid all emissions associated with
recycling, composting, combusting or landfilling the material.
Recycling typically requires less energy than producing goods
from virgin materials. Energy savings from recycling translates into
GHG savings because fewer fossil fuels are ___(7)____ to produce
energy.
Source reduction and recycling can also increase carbon storage in
___(8)_____. By preventing or reducing harvests of raw materials,
preserved trees continue to remove CO2 from the atmosphere.
Composting produces a useful product from __(9)_____ waste that
otherwise would have been landfilled, therefore composting helps
prevent methane emissions from and leachate formulation in the landfills.
Energy recovery at __(10)______facilities and landfills can
conserve resources by offsetting fossil fuels used for energy. Energy
recovery is often associated with electricity generation such as landfill
methane capture, although it can also offset fossil fuels used at industrial
sites, resulting in fewer GHG emissions.

114
 TRANSLATION
Task 1: Translate the following passage into Vietnamese
The rate of compost formation is controlled by the composition and
constituents of the materials, i.e.their Carbon/Nitrogen (C/N) ratio, the
temperature, the moisture content and the amount of air.
The C/N ratio is very important for the process to be efficient. The
micro organisms require carbon as an energy source and nitrogen for the
synthesis of some proteins. If the correct C/N ration is not achieved, then
application of the compost with either a high or low C/N ratio can have
adverse effects on both the soil and the plants. A high C/N ratio can be
corrected by dehydrated mud and a low ratio corrected by adding
cellulose. Moisture content greatly influences the composting process.
The microbes need the moisture to perform their metabolic functions. If
the waste becomes too dry, the composting is not favoured. However,if
there is too much moisture then it is possibly displaced the air in the
compost heap depriving the organisms of oxygen and drowning them.
A high temperature is desirable for the elimination of pathogenic
organisms. However, if temperatures are too high, above 75oC then the
organisms necessary to complete the composting process are destroyed.
Optimum temperatures for the process are in the range of 50-60oC with
the ideal being 60oC.
Aeration is very important and the quantity of air needs to be
properly controlled when composting. If there is insufficient oxygen, the
aerobes will begin to die and will be replaced by anaerobes. The
anaerobes are undesirable since they will slow the process, produce
odours and also produce the highly flammable methane gas. Air can be
incorporated by churning the compost.

Task 2: Translate the following passage into English

Bản chất kỹ thuật của công nghệ SERAPHIN
Mục đích của sáng chế là đề
xuất giải pháp xử lý triệt để rác thải
sinh hoạt; cung cấp phương pháp và
thiết bị xử lý chất dẻo thải nằm trong
rác thải sinh hoạt và tạo ra sản phẩm
hữu ích từ chất dẻo thải; cung cấp
phương pháp và thiết bị xử lý phần
rác không có chất dẻo thải bằng
115
phương pháp vi sinh và phương pháp đóng rắn vĩnh cửu bằng áp lực cao
để tạo thành các sản phẩm từ rác. Tập hợp các phương pháp được đề xuất
để xử lý triệt để rác sinh hoạt đô thị mà không cần chôn lấp.
Để đạt được mục đích nêu trên, sáng chế đề xuất phương pháp xử
lý chất dẻo thải bao gồm các công đoạn:
a) Rác thải sinh hoạt được chuyển đến trạm tập kết rác.
b) Đảo trộn, kiểm soát, phun chế phẩm khử mùi hôi và loại bỏ rác
cá biệt.
c) San, gạt, xúc bằng cơ giới lên băng chuyền vận chuyển rác vào
trạm xé rác. Trên băng chuyền, rác được quan sát bằng phương pháp thủ
công để loại bỏ rác cá biệt một lần nữa, sau đó được tuyển từ bằng một
thiết bị tuyển từ ở cuối băng chuyền để loại bỏ sắt.
d) Trạm xé rác xé các bao rác, cắt rác bằng các thiết bị đặc chủng
làm cho các rác thải có đặc tính giống nhau được cắt thành những kích
thước gần bằng nhau.
e) Rác qua trạm xé được đưa vào trạm tách lọc theo kích thước và
tỷ trọng bằng nguyên lý sàng ống quay. Phần lọt qua mắt sàng phần lớn
là bụi, tro, gạch, vụn hữu cơ từ thực vật và động vật đã cắt nát. Phần
không qua mắt sàng sẽ ra theo cửa thoát cuối sàng ống, đó là hỗn hợp có
phần lớn là chất dẻo, màng mỏng, giấy bao bì có màng mỏng, giẻ... ít bị
cắt nát hơn và có kích thước lớn hơn, cồng kềnh hơn.
Từ phần tách lọc này, rác sẽ được xử lý theo ba nhánh của ba quy
trình công nghệ riêng biệt:
1- Công nghệ áp lực cao – cho chất dẻo thải.
2- Công nghệ vi sinh – cho rác thải hữu cơ.
3- Công nghệ đóng rắn vĩnh cửu – cho phế thải vô cơ rắn.

116
 10 SUSTAINABLE DEVELOPMENT

Discuss the following questions with a partner

1. What do you think is sustainability?
2. What do you think is sustainable development?
3. Why is sustainable development important?
4. What do you think are goals of sustainable development?

Read the following paragraphs to answer the questions above

1. The word sustainability means the ability of a system or
organization to maintain a system or state indefinitely. In the
context of development and ecology, it relates to the capacity of
our present generation to meet its own needs without
comprimising the ability of future generations to meet their own
requirements. Hence, for a community to be sustainable it must
only use natural resources at a rate which can be replenished
naturally and at the same time it should try to preserve the
environment (Linsay, 2008).

117
 2. All definitions of sustainable development require that we see the
world as a system—a system that connects space; and a system
that connects time. When you think of the world as a system over
space, you grow to understand that air pollution from North
America affects air quality in Asia, and that pesticides sprayed in
Argentina could harm fish stocks off the coast of Australia. And
when you think of the world as a system over time, you start to
realize that the decisions our grandparents made about how to
farm the land continue to affect agricultural practice today; and
the economic policies we endorse today will have an impact on
urban poverty when our children are adults (International
Institude of Sustainable Development, n.d.).
3. Sustainable development goals include: (1) end poverty in all its
forms everywhere; (2) end hunger, achieve food security and
improved nutrition and promote sustainable agriculture; (3)
ensure healthy lives and promote well-being for all at all ages; (4)
ensure enclusive and quality education for all and promote
lifelong learning; (5) achieve gender equality and empower all
women and girls; (6) ensure access to water and sanitation for all;
(7) ensure access to affordable, reliable, sustainable and modern
energy for all; (8) promote inclusive and sustainable economic
growth, employment and decent work for all; (9) build resilient
infrastructure, promote sustainable industrialization and foster
innovation; (10) reduce inequality within and among countries;
(11) make cities inclusive, safe, resilient and sustainable; (12)
ensure sustainable consumption and production patterns; (13) take
urgent action to combat climate change and its impacts; (14)
conserve and sustainably use the oceans, seas and marine
resources; (15) sustainably manage forests, combat
desertification, halt and reserve land degradation as well as halt
biodiveristy lost; (16) promote just, peaceful and inclusive
societies; and (17) revitalize the global partnership for sustainable
development (United Nation, n.d.).

READING
Which goal of sustainable development do you think the campaign
described in the following text aims to achieve?

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 BREAKING THE BOTTLED WATER HABIT IN YOUR
COMMUNITY

What’s the problem with bottled water?

It seems like everywhere we go, from meetings to community
events, we’re offered bottled water to drink. Across the country, free
public water fountains have been edged out by vending machines selling
water in single-use plastic containers. However, clean, safe tap water is
still the best option for staying hydrated - not only is it far cheaper than
bottled water, but it’s also more environmentally friendly. Bottled water
creates a lot of waste, and the companies that sell it are profiting from an
essential resource that should be accessible and affordable to all.
The good news is that more and more cities, towns, schools and
businesses are taking action to break the bottled water habit. At least six
U.S. states, 140 cities and dozens of universities and national parks have
declared an end to spending on bottled water, saving millions of dollars
and boosting public confidence in the tap. Restaurants and cafeterias
across the country have pledged to stop serving bottled water in their
establishments.
Campuses and communities have developed an array of strategies
to decrease public dependence on bottled water and to encourage a return
to the local tap. Tactics range from public media campaigns promoting
safe municipal water to installing water refilling stations and to adopting
policies that ban the purchase or sale of bottled water outright.
Drinking water is a source of life, and we must stop viewing it as a
commodity that can be bought, sold and overused at will. By taking steps
to embrace the tap and get bottled water out of our homes, schools and
workplaces, we can reduce the impacts on our environment and
communities to build a better future together today.

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 Key Steps
Step 1: Find community members interested in breaking the bottled
water habit
Identify people in your community (school, workplace,
congregation, etc.) who are excited by the idea of reducing bottled water
use and the associated waste. Talk to neighbors, friends, fellow students
and others, encourage them to get involved and share your ideas on social
media sites and community lists. Raise the idea in an open letter in your
local newspaper and assemble a working group of supporters to rally
around the concept.
Step 2: Hold a meeting and designate a core team
At your first meeting, identify a core team to develop the campaign
and designate key roles such as a policy expert, an outreach coordinator,
a volunteer coordinator and a researcher who can track down information
on bottled water use your community (including who makes the key
decisions about purchases or sales). Consider coordinating or joining
with an existing group with related interests, such as a campus
environmental group or workplace sustainability team.
Step 3: Establish a target and goals for your campaign
What are you hoping to achieve? Targets can range from simply
raising awareness about the value and quality of public water to soliciting
pledges to phase out bottled water, and to supporting policies to ban its
sale or purchase. Do you want your institution to install filtered drinking
water fountains or refilling stations? To reduce overall spending on
bottled water? To terminate an ongoing contract with a beverage
company? Also, consider the type of bottles you’re targeting, from
smaller single-use bottles made from PET plastic to five-gallon “water
cooler” jugs. Consider a phased approach, starting with small steps like
awareness-raising and working toward broader policy change. Allow for
flexibility: in some cases such as emergencies, there may be a legitimate
need for using bottled water.
Step 4: Develop a timeline and messaging
Depending on your goals, your campaign could move quickly or it
could be a long one. The recent bottled water ban in Concord,
Massachusetts, resulted from a three-year effort by local activists.
Consider your talking points: Is your main motivation to reduce waste
and pollution in local landfills? To protect people’s health and the
environment? To fight corporate takeover of public water systems and
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the commodification of water? Nail down your messaging and sound
bites and create a Facebook page or website to lay out your arguments
and post updates about the campaign.
Step 5: Get public support and buy-in
If you’re pushing for action at the municipal level, approach local
businesses and event planners to see if they would support the initiative.
At your workplace, distribute flyers and hold an informational meeting
for staff about the campaign. On campus, rally fellow students around the
idea and give class presentations. Educate people with articles, facts,
pictures, etc. and build your contact list. Use social media to invite
colleagues, friends and family to events, tag them in photos and start
discussions. For resources and models, check out Food & Water Watch’s
Take Back the Tap, Corporate Accountability International’s Think
Outside the Bottle, the Green Schools Alliance’s S.T.O.P. initiative,
Canada’s Coalition for Bottled Water Free Communities and Ban the
Bottle.
Specific ways to generate support for your campaign include:
1. Host a creative and fun public awareness party. There are lots
of ways to engage people around bottled water, from tabling and guest
lectures to film screenings, flash mobs, rallies and concerts. Organize an
event for Bottled Water-Free Day (the second Thursday in March) or for
World Water Day (March 22). Host a party at your house, lunch room,
dorm room, or a local park and ask guests to sign a pledge/petition or to
write letters/emails to higher-ups calling on them to take action. Build a
“tower of consumption” or other creative display to demonstrate just how
much plastic gets tossed daily. Distribute a survey or set up a taste test
booth as a way to gather petition signatures (you’d be surprised how
many people prefer the taste of tap water). Host or organize a screening
of the films “FLOW,” “Tapped,” or “Blue Gold”.
2. Develop a pledge to encourage folks to go bottled-water-free.
When people sign their name to something, they’ll generally read what
they’re signing, and many will take voluntary action to follow up on their
commitment. Get a pledge from your legislators to encourage city
employees to stop using single-serving bottled water at city offices,
meetings and events. Get local restaurants to pledge to voluntarily stop
selling and serving bottled water. Examples of existing pledges to ditch
bottled water include the Tap Water Pledge, the Think Outside the Bottle
pledge, the Take Back the Tap pledge and tappedthemovie.com’s
declaration page.

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 3. Host a bottled-water-free event. Demonstrate how easy it can be
to shift the culture in favor of tap water. Work with institutional event
coordinators to ensure that they provide reusable water pitchers, cups and
bottles at meetings and events. Purchase reusable jugs with pumps at
your local hardware store, hook them up to the tap and have volunteers
on hand to refill them. Place a filtered-water pitcher in every fridge in
your office or dorm. Get a checklist for taking action and learn more
about ways to “Free Your Event from Bottled Water.”
4. Launch a media campaign promoting the benefits of local tap
water. New York’s “Celebrate the City’s Clean Drinking Water Campaign”
included ads in area newspapers highlighting the city’s good water quality
and supply. Besides, a $1 million advertising campaign by the Los Angeles
Department of Water and Power in 2003 reminded residents of the safety and
quality of local tap water. However, you don’t need a huge budget to tout the
benefits of local water (check out UC Berkeley’s I Heart Tap Water
initiative). Request an annual water quality report from your municipal utility
to verify local drinking water safety and learn how to read it.
Step 6: Encourage the distribution and use of reusable bottles
Encourage people to carry reusable water bottles as part of their
daily routine. Get your university or workplace to include stainless steel
bottles in orientation or welcome kits, as well as a map of nearby public
water fountains. Approach local businesses - from grocery stores and
construction offices to sports teams and big-box stores - to see if they are
willing to donate safe reusable bottles with their logos that you can use as
promotional or raffle items at your events. Make it fun! Host a contest
for bringing in and using reusable bottles at work or school; see which
department or team can truly “ban the bottle” and provide the winners
with a lunch party!
Step 7: Lobby for public water fountains and filling stations as well
as spread the word about existing ones
Convince your municipality or institution to install filtered water
bottle filling stations or new public water fountains with a high arc for
easy filling. If you’ve got a smartphone, use Food & Water Watch’s
handy Tap Buddy app or the Pacific Institute’s We Tap app to find and
share the locations of water fountains. Find out from your local water
department if your municipality provides a free water tanker/trailer
service for special community events - if not, suggest it to them. At the
same time, lobby for the removal of bottled water from vending
machines and for the termination of contracts with corporate suppliers.

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Step 8: Push for formal policy change
Get a real commitment in writing! Formal policies, including
legislation, can provide an institutional mandate for reducing or
eliminating the purchase of unnecessary bottled water and help to ensure
timely action and accountability. Getting the top people from your
institution involved is key to any campaign:
At your school or workplace, request a meeting with your president
or vice president, catering manager, student body president, human
resources manager, etc. Provide information, present your case and ask
for support in drafting a policy or ban, changing procurement practices,
and/or installing refilling stations. If your institution has signed a
beverage exclusivity contract, ask to see it and strategize on efforts to end
it. Sell higher-ups on the idea that taking action on bottled water will be
great for PR and make the institution a model of green leadership.
For K-12 schools, get a school board member to introduce a motion
to stop bottled water sales in vending machines and cafeterias, and to
move toward a policy to phase out the sales on school property.
Encourage schools to install refill stations and create bottled-water-free
zones and events (including walk-a-thons and outdoor events). Gather
petition signatures from staff, students, and parents.
At a municipal level, contact your mayor or city councillors and
encourage them to promote local tap water at meetings and events, and to
pass a resolution phasing out or banning the sale and purchase of bottled
water (as in Concord and San Francisco). Call on public officials to cut
taxpayers spending on bottled water and to support refilling stations and
strong public water systems, as well as lobby for a tax on bottled water to
fund public water fountains.
Step 9: Celebrate your successes and don’t take no for an answer!
Continue to get people excited and involved and celebrate your
successes, especially if you’re encountering hurdles. Reach out to
reporters and send them announcements when your campaign hits a
milestone. Document your efforts and share your stories with others.
Host a community celebration to acknowledge your hard work and raise
awareness of your efforts, so more people will want to become involved
as you push for further action. Don’t be discouraged if things take longer
than expected, and above all, remember to have fun with your efforts to
Unbottle Water!
(Center for a New American Dream, n.d.)

123
Task 1: Decide whether the following statements are TRUE, FALSE or
NOT GIVEN
1. ______ Bottled water is popular not only in developed countries but
almost everywhere.
2. ______ The only reason why bottled water habit should be ended is
that it is not environmentally friendly.
3. ______ Bottled water is more expensive but safer than tap water.
4. ______ That states, cities, universities, national parks, restaurants
and cafeterias in the US have tried to stop using bottled water can
encourage residents to trust in the quality of tap water.
5. ______ A lot of efforts have been made to improve the quality of
tap water so that the public can less rely on bottled water.

Task 2: Nine steps of the Unbottle Water Campaign are given in the
reading passage. Identify the step that the following work belongs to
Work Step
1. Identify what you and your group want to achieve by the end of
the campaign
2. Get policy makers in communities or organizations to be
involved in the campaign as well as to encourage changes in
regulations or policies
3. Form a group of people who have the same concerns or
interests
4. Get people in your community to be involved in the campaign
5. Record and publicize your efforts and successes when
appropriate
6. Plan the work and time according to the goals or the scale of
your campaign
7. Assign different tasks to group members
8. Encourage the provision and availability of alternatives to
bottled water in public places
9. Attract attention and supports for your campaign from the public

124
Task 3: Discuss the following questions
1. Is drinking bottled water encouraged in your country? Why/
why not?
2. In what way bottled water harm the environment? Do you think
impacts of bottled water on the environment are at alarming
level?
3. Which of the steps of the Unbottle Water Campaign in the
reading passage is the most difficult? Explain your answer?
4. Would you like to carry out the same campaign in your
community or country? What are difficulties you may face in
this project?

VOCABULARY
Task 1: Match the words in column A with their meaning in column B

Column A Column B
1. Edge a) move or move something slowly and
carefully in a particular direction
2. Hydrate
b) a serious promise or agreement, especially
3. Commodity
one made publicly or officially
4. Rally around
c) gradually stop using or providing
5. Designate something
6. Solicit d) a written request signed by a lot of people,
7. Phase out asking someone in authority to do
something or change something
8. Nail something
down e) ask someone for money, help or
information
9. Raffle
f) make something absorb water
10. Pledge
g) a problem or difficulty that you must deal
11. Hurdle with before you can achieve something;
12. Petition obstacle
h) a competition or game in which people buy
numbered tickets and can win prizes
i) choose someone or something for a
125
 particular job or purpose
j) reach an agreement or a decision, usually
after a lot of discussion
k) work together in order to help somebody
who in a difficult or unpleasant situation
l) a product or a raw material that can be
bought and sold

Task 2: Complete the sentences with words in the box

hurdle edged lobbying solicit

legitimate touting pledged termination
1. The manager _____________ $100,000 to the orphanage at the
fund-raising dinner.
2. They kept _____________ the benefits of using dietary
supplements and we were finally convinced.
3. Finding enough money for the project was the first
____________ that we encountered.
4. The governor sent two officials to Mexico City to _________aid
from the President.
5. The actress ___________ away from the crowd and headed for
the car waiting outside the building.
6. In some cases, such as cancer treatment, the prescription of
increasing doses of morphine is ____________.
7. That we failed to comply with agreed conditions resulted in
_____________ of contracts with many valued customers.
8. We have been ___________the management board to carry out
the pilot project.

TRANSLATION
Task 1: Translate the following passage into Vietnamese
As the saying goes, you are what you eat: anything that hitches a
ride on your produce, meat, coffee and whatever else you consume will
126
wind up affecting your body, for better or for worse. In the case of
conventionally grown or raised food, its chemical pesticides, herbicides,
fertilizers and hormones which ensure large yields that are good for
commercial success but often bad for the health of the consumer.
Illness, disease and lower nutritional value are all possible
consequences of consuming the readily available, chemically laced
selection of products found in most grocery stores. The damage extends
to the environment, as the harsh, artificial practices of much large-scale
farming affect the quality of the surrounding land and water. Fortunately,
the organic food movement is gaining strength, and it's easier than ever
to make the change to a lifestyle that's healthier for you and your
environment.
Discover what you can gain from an organic diet, and how to find a
good retailer for everything from organic coffee to organic pet food.
In addition to organic food's being grown without pesticides or
artificial fertilizers, most countries require it cannot be genetically
modified if it is to be considered organic. Organic food production is
very strictly regulated, and only the producers who can satisfy all of the
requirements of the governing inspection agency can earn the special
organic certification. These days, you'll find the
words organic, natural and sustainable plastered across a variety of
labels, but only a certified organic product comes with a guarantee that
the item is free of harmful chemical fertilizers and other artificial
residues.
Organic food statistics have shown a 20 percent growth in the
worldwide organic food industry every year since the early 1990s, and
it's only gaining strength. However, it's no surprise that organic
production is growing in popularity, since the improved taste and the
enormous health benefits of organic food are not easily ignored. Indeed,
organic food has been found to contain 50 percent more nutrients than
non-organic food, and you can eliminate several dozen pesticides from
your everyday diet by switching to organic produce.
(The renewable planet, 2014)

Task 2: Translate the following passage into English

Mục tiêu dự án trồng mới 5 triệu ha rừng theo Quyết định số
661/QĐ-TTG ngày 29/7/1998

127
 1. Trồng mới 5 triệu ha rừng cùng với bảo vệ diện tích rừng hiện có
để tăng độ che phủ của rừng lên 43%, góp phần đảm bảo an ninh môi
trường, giảm nhẹ thiên tai, tăng khả năng sinh thủy, bảo tồn nguồn gen
và tính đa dạng sinh học.
2. Sử dụng có hiệu quả diện tích đất trống, đồi núi trọc, tạo thêm
nhiều việc làm cho người lao động, góp phần xóa đói giảm nghèo, định
canh, định cư, tăng thu nhập cho dân cư sống ở nông thôn miền núi, ổn
định chính trị, xã hội, quốc phòng, an ninh, nhất là ở vùng biên giới.
3. Cung cấp gỗ làm nguyên liệu để sản xuất giấy, ván nhân tạo, đáp
ứng nhu cầu gỗ, củi và các lâm đặc sản khác cho tiêu dùng trong nước và
sản xuất hàng xuất khẩu, cùng với phát triển công nghiệp chế biến lâm
sản, đưa lâm nghiệp trở thành một ngành kinh tế quan trọng, góp phần
phát triển kinh tế - xã hội miền núi.

FUTHER READING
Which goal of sustainable development do you think the plan described
below aims to achieve?
GREEN BUILDING
Harness the sustainable power of green home building

The green building movement is gaining more and more

momentum as environmentally conscious homeowners, which aim to
make their houses more ecologically sustainable and energy-efficient.
Strongly rooted in energy-efficient home design, green home building

128
also aims to reduce waste, make use of sustainable materials and
optimize the quality of the indoor environment.
While a sustainable construction plan is ideally implemented when
you're building a new home, you can also convert your existing house
into a more energy-wise and ecologically efficient space by renovating.
The first step is to learn about the major concepts in sustainable building
and understand how they can be applied to your home.
Energy Efficient House Plans
When it comes to new homes, sustainable building concepts focus
on reducing waste, maximizing resources and consuming less energy. For
example, sustainable construction may include plumbing installations
that recycle rain and waste water, energy efficient HVAC systems that
draw power from on-site generators, and intelligent lighting layouts that
reduce your expenditure of electricity.
Green architecture also emphasizes the use of sustainable
construction materials. Metal roofing, sustainable lumber and many other
ecologically friendly raw materials are incorporated whenever possible.
Green Home Building Tips for Renovators
You can also draw on green home building practices when you're
performing renovations to lower your energy bills and lighten your
carbon footprint. The simplest measures you can take include
using energy efficient appliances and installing energy efficient windows.
Appliances and windows are among the worst culprits in terms of home
energy inefficiency, and making smarter choices when replacing old
installations is better both for you and the environment. Improving your
home's insulation is also something many ecologists highly recommend.
Selecting sustainable materials for your interior decorating needs
also has many advantages. For example, both cork and bamboo
flooring have a reduced environmental impact.
While the costs of green home building and renovating can be
higher than their traditional counterparts, you should look at your efforts
as an investment in your future. Not only do green building strategies
help you save thousands of dollars on your energy bills, they can also
dramatically increase the value of your home, making it more attractive
on the resale market to like-minded people seeking a more ecologically
responsible way to live.
Green Building Materials: an overview of green building
products
129
 Homeowners are becoming increasingly aware of many benefits
offered by green building materials. In addition to dramatically increased
energy efficiency, green building products also reduce maintenance and
replacement costs by offering a longer life; have increased flexibility in
terms of design and implementation; can improve indoor air quality; and
promote better health for the building's occupants.
Using green building products and recycled building materials has
a trickle-down effect with a positive global impact. Choosing them helps
to conserve the world's non-renewable resources and minimizes the
significant ecological impact that results from extracting, processing and
transporting raw materials from their place of origin to their point of use.
Examples of Eco-Friendly Building Materials
Some of the most commonly implemented green building materials
include:
o Metal roofing: The advantages of metal roofing, from an
environmental standpoint, include low maintenance and long life,
which reduces waste. Metal roofing products also help you optimize
your ability to maintain indoor climate control while using less
energy.
o Sustainable lumber: Some forward-thinking companies in
the logging industry have introduced measures to ensure that forestry
products are drawn from sustainable, smartly managed resources.
Supporting these ventures ensures that you don't contribute to
deforestation, endangerment of wildlife and illegal or questionable
logging practices.
o Energy-efficient glass: Inefficient windows are the number
one cause of home energy wastage. Installing energy-efficient glass
helps you save money on your heating and cooling bills while
diminishing your carbon footprint.
o Quality insulation: Insulation made from environmentally
friendly compounds like soybean oil and recycled plastic go a long
way toward improving your home's ability to use energy intelligently.
You can also incorporate high-quality used building materials into
home construction and renovations. This is a great way to lower costs
while doing Mother Nature a favor.
More Energy Efficient Products for Your Home

130
 In addition to building materials, there are many other measures the
ecologically aware homeowner can implement to help build a greener
tomorrow. Choosing energy-efficient home appliances and plumbing
systems that recycle water will help you reduce your consumption of
resources.
Whether you're building a new home or renovating your current
one, there are many things you can do to reduce your environmental
impact. Save money and help preserve the health of the planet by
choosing green building products whenever possible.
(The renewable planet, 2014a,b,c)

131
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