EP1017638A1

EP1017638A1 - Waste water treatment system

Info

Publication number: EP1017638A1
Application number: EP98931837A
Authority: EP
Inventors: Humberto Urriola
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-07-02
Filing date: 1998-07-02
Publication date: 2000-07-12
Also published as: AUPO768897A0; WO1999001385A1; EP1017638A4

Abstract

A waste water treatment apparatus (1) for effluent containing biodegradable solids having a first chamber (3) for retaining the solids while allowing liquid effluents to pass therethrough to a filtering chamber (11) which contains a filter medium (13, 32). The solids (biomass) are digested by worms and/or bacteria in the first chamber (3) and the liquid effluents from the first chamber (3) are treated by bacteria which is in the filter medium (13, 32). The thus purified water passes into the holding chamber (14) from where it is used for gardening or as required.

Description

Waste Water Treatment System

The present invention refers to a waste water treatment system, and in

particularly a waste water treatment system for on site treatment of liquid

wastes, such as sewerage and slurries:- known as a point source solution..

In the present treatment of liquid wastes and sewerage, the liquid waste

is transported by underground impervious piping or open channel, to a central

treatment system or in extreme cases simply discharged into waterways or in

the case of mine effluent, the effluent is usually discharged into tile dams or

open basins without treatment. A centralised treatment system requires the use

of pumps, clarification equipment, and chemicals. The cost of maintaining and

installing such systems is extremely high, as it requires an extensive network of

impervious piping or open channels which usually occupies a large area of

valuable land. Further problems arise during heavy rain, because excess storm

water run off in some areas are directed into the sewerage system, which

results in raw sewage discharge from the sewerage systems into the streets

and the river systems or held in tile dams or open basins. Other problems occur

with broken pipes leaking untreated effluent into the local environment and

eventually into the water table, aquifers and river systems. Such leakage of untreated effluent can cause problems such as polluted

aquifers, river ways, soil contamination, algae blooms, unpleasant toxic

smells, air pollution, and illnesses, as well as reduction in the fauna and flora..

Further in isolated communities, such as mining settlements, and in

other areas where sewerage is not connected, individual on site sewerage

collection systems such as septic tanks, biological toilets and incinerator toilets

have been used, with varying degrees of success. However, increasingly, laws

are being enacted to prevent inefficient and unsafe system, including burning of

waste, because of the resultant air and water pollution, and to phase out septic

systems.

Problems, also, occur with the treatment of other waste water, both

domestic and industrial. In some systems bathroom and kitchen sink water are

fed directly into the sewerage system, thus greatly increasing the volume of

effluent, containing contaminated biomass in various degrees of decomposition,

travelling through the sewerage system. In other systems, these waste waters

are fed into anaerobic grease traps where the overflow percolates into the soil

and into the water table, or as run off and into the water ways. Some of this

liquid waste is high in phosphorus and nitrogenous compounds, which cause algae blooms and high COD (chemical oxygen demand) and BOD (biological

oxygen demand), hence deoxygenate the river systems.

The present invention seeks to ameliorate the above problems by

providing an on site liquid effluent treatment apparatus for effluent, containing

biodegradable solids, comprising:

a first chamber adapted to receive untreated effluent, said chamber

having at least a permeable portion to allow liquids to pass therethrough and to

retain the biodegradable solids in the first chamber, thereby substantially

dewatering the solids, and containing bacteria and/or worms to digest the

biodegradable solids;

a second chamber in cascade with the first chamber and separated

therefrom with an air gap, said second chamber containing a suitable filter

medium, such that liquid which passes through the first chamber percolates

through the filter medium ;

a third chamber located below the second chamber to receive the

treated liquid from the second chamber; and

an outlet from said third chamber to allow removal of the treated liquid

from the third chamber. The liquid in the third chamber can be oxygenated with air or oxygen, or

ozone, depending upon their toxicity levels.

In another form, the present invention provides an on site waste water

purification apparatus for purifying water containing liquid or dissolved

contaminants, comprising:

a first holding chamber adapted to receive the waste water mixture, said

chamber having a permeable base to allow liquids to pass therethrough;

a first filter chamber, in cascade with the first holding chamber, and

containing a suitable filter medium, such that liquids which passes through the

first holding chamber percolates through the filter medium ;

at least a second holding chamber, located below the first filter chamber

to receive the filtered liquid from the first filter chamber, and having a

permeable base; and

at least a second filter chamber in cascade with the at least second

holding chamber, and containing a suitable filter medium, such that liquid which

passes through the at least second holding chamber percolates through the

filter medium,

whereby the liquid or dissolved contaminants are separated from the

water as the water, firstly, percolates through the various filter medium, with the liquid or dissolved contaminants remaining in the filter medium, where it is

digested by bacteria.

The present invention will now be described with reference to the

accompanying drawings in which:

Figure 1 illustrates an on site liquid effluent treatment apparatus

according to one embodiment of the present invention;

Figure 2 illustrates an on site liquid effluent treatment apparatus

according to another embodiment of the present invention;

Figure 3 illustrates the liquid effluent treatment apparatus shown in figure

2, in a system for treating domestic washing water;

Figure 4 illustrates the liquid effluent treatment apparatus shown in

figures 1 or 2, in a system for treating sewerage;

Figure 5 illustrates an on site liquid effluent treatment apparatus

according to a further embodiment of the present invention; Figure 6 illustrates an on site liquid effluent treatment apparatus

according to a further embodiment of the present invention;

Figure 7 illustrates an on site liquid effluent treatment apparatus

according to a further embodiment of the present invention;

Figure 8 illustrates an oil water separator according to an embodiment of

the present invention;

Figure 9 illustrates a view of a piece of drainage cell as shown in

Australian patent no. 593085 which is suitable for use in the present invention;

and

Figure 10 shows actual test results of a trail of the filtration system of the

present invention.

In a full flush of a toilet, normally a minimum of six litres of flushing water

is used. Thus during a day a large volume of water is as well as the faecal

solids, which contain approximately 82-92% water, are flushed into the sewer

system. As the population of areas grow the load on the sewerage system

increases, and in some cases the system cannot cope. However the present invention, rather than have a centralised treatment

centre, provides an on site treatment apparatus which could be used for a

single toilet or a series of toilets, as well as bathroom and kitchen liquid waste,

thereby eliminating the need for a large network of piping throughout the city

and suburbs, and the subsequent maintenance cost and risks of major

overflows. Further the retention of the treated water, which could be used for

gardens , washing or other non potable uses, would lower the water usage from

the reservoirs.

The invention will now be described with reference to treatment of

domestic liquid effluent. As shown in figure 1 , the liquid waste treatment

apparatus (1 ) comprises an inlet pipe (2) to convey waste from the toilet system

(see figure 4) or the kitchen sink or bathroom (see figure 3) of a house into a

waste receiving chamber (3). The chamber (3) contains a geofabric or micro

filter bag (4), shaped so as to line the walls of the chamber (3).

The base (5) of the waste receiving chamber (3) is perforated and could

® be constructed, as shown in figure 9, of modules of ATLANTIS DRAINAGE

CELLS, which are shown in Australian patent no. 593085. These modules have

two parallel perforated surfaces (9 &10), joined by columnar members (27), forming an air gap (8) therebetween. On the under side of the support surfaces

(28) are upturned walls (29) which form wells (30) in which effluent is retained.

Therefore when the toilet is flushed the liquid waste and the faecal solids

are collected in the waste receiving chamber (3) as shown in figure 1 , where

the urine and liquid wastes drain through the bottom (5) of the waste receiving

chamber (3) . Suitable bacteria is placed in the waste receiving chamber (3),

together with manure worms. The worms and the bacteria digest the faecal

solids, which remain in the waste receiving chamber (3), in a very fast time, and

leave, as residue, worm castings. The worms are capable of eating their own

weight a day.

A filter chamber (11 ) lies directly below the receiving chamber (3), to

receive the filtered liquid waste from the waste receiving chamber (3). A

microfilter medium (4) such as a geofabric lies below the bottom surface (10) of

the base (5) of the receiving chamber (3), and a further microfilter medium (4)

such as a geofabric lies above the top surface of the perforated base (12) of the

filter chamber (11 ), which could be constructed, as shown in figure 1 , of

modules of ATLANTIS " DRAINAGE CELLS. Between the micro filter layers

(4), the chamber can be filled with a granulated filter medium (13). This medium

could be any suitable material such as sand or a mixture of sand and zeolite, together with a decontamination agent and of any suitable grain size. In the

embodiment shown the material is a granulate mixture of zeolite, with Borax as

the decontamination agent. Suitable bacteria is also preferably used in the filter

medium, to assist in the removal of contaminants.

However as shown in figure 1 , the granulated filter medium (13) could be

contained in several bags (6) of microfilter medium (4), which are secured

across the filter chamber (11 ) to ensure that all liquid must pass through the

filter medium (13). Each bag could have a different strain of bacteria.

The liquid waste, that passes from the receiving chamber (3), falls

through the air gap (8), onto the filter medium (13), and spreads along the filter

medium bed and percolates through the interstices between the grains of the

filter medium (13), where the pollutants are digested by the bacteria in the filter

medium (13).

In the process of liquid passing through a granular layer, liquid will be

retained in the granular layer in an increasing amount from the top of the layer

to the bottom, with very little or no liquid being present at the top to being

almost fully saturated with water at or adjacent the bottom of the layer. However

there are still air pockets in the interstices between the grains, in the lower level of the layers This retained water is known as "perch water". Further as liquid

percolates down through the layers, air flows upwardly. Therefore, as the

pollutants percolate through the granular layer, they pass from an aerobic

region through an increasingly anaerobic region. The thickness and top surface

area of the filter medium (13) is such that the retention time of the liquid in the

filter medium (13) is sufficient to remove the impurities to a predetermined

degree, such that the treated water is useable, for example, for watering the

garden.

The treated water then drips into a holding chamber (14) where it is

aerated as it falls into the chamber (14), and exits through the outlet (17). To

assist in the treatment process air or oxygen could be pumped into the treated

water in the holding chamber (14), to increase the aeration of the treated water

and also to increase the flow of oxygen through the filter medium (13). Also air

or oxygen could be fed into the lower levels of the filter medium (13).

Additionally a small mercury lamp could be used to convert some of the oxygen

into ozone, in the air that is pumped into the treatment system.

A further embodiment is shown in figure 2, which is of similar

construction to the embodiment shown in figure 1 except that the base (5) and

the lower walls of the waste receiving chamber (3) have an impervious insert (7) to form a well (15) to retain a depth of the liquid as well as the faecal solids

in the waste receiving chamber (3), while the remainder of the liquid effluent

flows over the impervious insert (7) and passes through to the filter chamber

(11 ). Suitable bacteria and a quantity of water is placed in the well (15), where

the bacteria digest the faecal solids in a very fast time.

The present invention provides separation of the faecal solids from the

liquid wastes, so that each can be treated separately. The solids being

separated, and digested by worms and/or specific bacteria, and the liquid

wastes: flushing water, urine, faecal liquids, and liquids liberated by the

digestion of the faecal solids, percolating through a reactive filter material where

the bacteria breaks down the organic material into water and carbon dioxide,

and breaks down ammonia and ammonium ions into nitrogen and water while

producing oxygen, and retains metal ions and phosphorus, within the filter

medium (13).

The results of a trial on a stormwater drainage system, using of a

waste water treatment system according to an embodiment of the present

invention is shown in figure 10. As can be readily seen the pollutants have been

greatly removed. In an embodiment of the present invention, not shown, there are three

waste receiving chambers; each chamber with an air gap surrounding it, with a

barrier between each chamber to prevent flow between the chambers. Hence

when the first chamber becomes full of worm casings or bacteria and over flows

into an adjacent chamber, the feed of sewerage waste is then transferred to

one of the other chambers and the process continued. The full chamber is then

left to mature; ie all faecal waste has been converted into worm casings or

digested down to a safe product, and after maturing the microfilter bag (4) and

its contents is removed and a new bag inserted for future use.

The walls of the waste receiving chambers are porous and could be

constructed, as could be the base, as shown in figure 1 , of modules of

® ATLANTIS DRAINAGE CELLS, so as to provide an adequate air flow around

each chamber.

As shown in figure 3, the waste water treatment apparatus (1 ) could be

connected to sink or bathroom waste water outlet and the treated and filtered

water passed to underground percolation tanks (16) which supply water to the

surrounding plants. The tanks (16) could be contained in an impervious well

(23). In figure 4, the outlet from the toilet is feed into the waste water

treatment apparatus (1 ), as shown in figure 2, and the water fed to a series of

tanks (16) contained in an impervious well (24). A pump (25) can be used to

spray water held in the well (24) onto gardens. Further instead of using the

impervious well (15) to maintain a head of water in the waste receiving chamber

(3), the outlet pipe (17) could be raised vertically, thereby creating the head at

the level of the outlet.

The various tanks (16) and their walls can be constructed, as shown in

figure 1 , of modules of ATLANTIS® DRAINAGE CELLS, the subject of

International patent application no. PCT/AU94/00771.

A further embodiment is shown in figure 5, for use with a larger dwelling

such as a block of units. In this case the treatment systems uses a large

moveable container (18), which, when full, could be disconnected from the

system and removed and replaced by a fresh container.

The system works similarly to the system described previously, toilet

wastes and kitchen and bathroom wastes are fed in through an inlet pipe (2)

into a waste holding chamber (19), which contains suitable bacteria and worms,

as mentioned previously, to digest the faecal solids, while the liquid wastes flow from the waste receiving chamber (19), through the perforated side walls (20)

and base (21 ), through an air gap (8) to a lower first filter chamber (11 ).

Further the chamber 19 could have a layer of filter medium (13) containing only

bacteria, as described previously. As shown the walls of the waste receiving

chamber (19), could be made of tank modules (16) as described in International

patent application no. PCT/AU 94/00771. Further the waste receiving chamber

In this embodiment several filter chambers (11 & 22) are used in

cascade. Filter medium (13), as mentioned in the first embodiment is used, and

each filter chamber (11 & 22) is separated by an air gap (8). Hence a "perch

water" table is formed in each filter chamber (11 & 22), with the resultant

gradient of aerobic to increasingly anaerobic reaction down through the filter

medium of each filter chamber (11 & 22).

By using multiple layered filter chambers, separated by an air gap,

different reactive material and bacteria, can be placed in each filter chamber to

target specific pollutants. Again, as described above, the input of air or

generated ozone can be used to increase the efficiency of the system and

The treated water percolates through the various filter chambers (11 &

22) and is collected in the lower chamber (23), where it is removed for use for watering the gardens or, depending upon the degree of treatment, for washing

or drinking.

A further embodiment is shown in figure 6, which is similar in

construction to that shown in figure 5 except that a well (15) is formed in the

waste receiving chamber (3) by an impervious insert (7) and air (31 ) is passed

into the holding chamber (14).

Figure 7 illustrates a further embodiment which is similar to that shown in

figure 6 except that the filter medium in the filter chamber (11 ) is replaced by

layers of modules (32) of ATLANTIS " DRAINAGE CELLS, according to

Australian patent no. 593085, an example of which is shown in figure 9. The

drainage cells have small wells (30) to hold liquids in which bacteria collects

and the layers of drainage cell modules act as a trickle tower. Further the

surfaces of the plastics material of the drainage cells become coated with

bacteria and the bacteria digest the effluent.

Thus the above embodiments provide the following features:

• diluting or dewatering of the faecal solids;

• anaerobic or aerobic degradation of the faecal solids by bacteria

and/or worms to provide a useable by product • filtration through the filter medium with, in the case of granulated filter

medium, variable perch water through the filter medium;

• removal of pollutants from the water systems; and

• saving of valuable land due to on site treatment and disposal or

usage.

A further embodiment is shown in figure 8 for the purification of water

contaminated with liquid or dissolved effluent The operation of this apparatus

will now be described with reference to the separation of water and oil. This

embodiment works in the similar way to the previous embodiments, except

there are no worms or bacteria in the initial receiving chamber (24).

A filtered oil water mixture is fed into the initial holding chamber (24)

where the water (25) and oil (26) begin to separate, depending upon the

amount of liquid in the chamber. The water and oil permeates through

successive layers of filter chambers, filled with suitable filter medium, such as

those mentioned previously, containing oil digesting bacteria, and holding

chambers.

Thus after using a predetermined number of stages the water has been

separated from the oil, which remains in the filter material for digestion. When the filter medium becomes spent, either the whole container is replaced or the

system dismantled and the spent filter medium replaced.

The filter chambers can be of any suitable thickness and porosity to suit

the requirements. The various chambers and their walls can be constructed, as

shown in figure 1 , of modules of ATLANTIS® DRAINAGE CELLS.

The on-site units could be adapted for connection to a single toilet or a

single sink outlet and then fed to appropriate holding tanks for use in gardening

washing or drinking, or dispersion tanks which are surrounded by a layer of

suitable sand to allow the treated water to disperse back into the soil where it is

used by surrounding trees and plants.

It should be obvious to people skilled in the art that alterations and

modifications could be made to the above described embodiments without

departing from the scope and spirit of the present invention.

Claims

The claims defining the invention are as follows:

1. An on site liquid effluent treatment apparatus for effluent, containing biodegradable solids, comprising:

a first chamber adapted to receive untreated effluent, said chamber

retain the biodegradable solids in the first chamber, thereby substantially

dewatering the solids, and containing bacteria and/or worms to digest the

biodegradable solids;

a second chamber in cascade with the first chamber and separated

therefrom with an air gap, said second chamber containing a suitable filter

medium, such that liquid which passes through the first chamber percolates

through the filter medium ;

a third chamber located below the second chamber to receive the

treated liquid from the second chamber; and

an outlet from said third chamber to allow removal of the treated liquid

from the third chamber.

2. An on site liquid effluent treatment apparatus according to claim 1 ,

wherein the filter medium contains bacteria to digest the effluent.

3. An on site liquid effluent treatment apparatus according to claim 1

or 2, wherein the first chamber has perforated walls and floor covered in a

geofabric or micro filter material.

4. An on site liquid effluent treatment apparatus according to any

one of the preceding claims, wherein the filter material is a granulated material

layered between two layers of geofabric or micro filter material.

5 An on site waste water purification apparatus for purifying water

containing liquid or dissolved contaminants, comprising:

a first holding chamber adapted to receive the waste water mixture, said

chamber having a permeable base to allow liquids to pass therethrough;

a first filter chamber, in cascade with the first holding chamber, and

containing a suitable filter medium, such that liquids which passes through the

first holding chamber percolates through the filter medium ;

at least a second holding chamber, located below the first filter chamber

to receive the filtered liquid from the first filter chamber, and having a

permeable base; and

at least a second filter chamber in cascade with the at least second

holding chamber, and containing a suitable filter medium, such that liquid which passes through the at least second holding chamber percolates through the

filter medium,

whereby the liquid or dissolved contaminants are separated from the

water as the water, firstly, percolates through the various filter medium, with the

liquid or dissolved contaminants remaining in the filter medium, where it is

digested by bacteria.

6. An on site waste water purification apparatus according to claim

5, wherein the first chamber has perforated walls and floor covered in a

geofabric or micro filter material.

7. An on site waste water purification apparatus according to any

one of claims 5 or 6, wherein the filter material is a granulated material layered

between two layers of geofabric or micro filter material.