Case Study on 145MLD Sewage Treatment Plant (STP) (SBR Technology) in

Gwalior, India

Er Alok Gupta*
Dr. Anupam Jain**

Abstract

Water scarcity and pollution are major environmental challenges faced by many cities in
the world. The treatment of waste water was introduced to overcome and find a solution to water
scarcity. A key by implementing Sewage Treatment Plant was aimed at treating the wastewater
generated by the city and making it suitable for reuse, at least for agricultural purposes. With
time there are many technologies to set up an STP. Nowadays, as the land prices of the cities are
increasing and the land in the cities is limited, advanced and new STP technologies are
introduced that require less space as compared with the older technologies also, with an
advanced treatment process called Sequential Batch Reactor (SBR), which has several
advantages over conventional activated sludge processes. The SBR technology has been
successful in achieving high efficiency of removing 95% of organic matter and suspended solids,
and the treated wastewater can be used for industrial and agricultural purposes, reducing the use
of freshwater resources for agriculture and gardening purposes. Implementing the STP has also
led to the rejuvenation of nearby water bodies, reducing the pollution in rivers and thus
maintaining rivers. The success of this project sets an example for other cities to follow and
adopt sustainable wastewater management practices.

KEYWORDS: Sewage treatment plant (STP), Waste Water Treatment,

Environmental impact, Sequential Batch Reactor (SBR), Agricultural use,
Sustainable wastewater management practices.

____________________

Introduction
This case study of 145 MLD sewage treatment plants (STP) implemented in Gwalior city,
Madhya Pradesh, India. The city was facing a severe water crisis due to the depletion of
freshwater resources. With a rapidly increasing population and urbanisation, the demand for
freshwater resources has increased, leading to the depletion of these resources. Moreover, the
discharge of untreated wastewater into water bodies has led to severe pollution, further
exacerbating the water crisis. To address this issue, the local government of Gwalior decided to

* Director, Sai Nath Renewable Energy Pvt. Ltd., Jaipur, Rajasthan, India.
** Asso. Prof Commerce & Mgmt, Poddar International College, Mansarover, Jaipur, Rajasthan, India.
implement a new sewage treatment plant (STP) and enhancing the treatment capacity to 145
MLD (million litres per day). The STP was designed to treat the wastewater generated by the
city and make it suitable for use in agriculture and parks (municipal), thereby reducing the usage
of freshwater resources. This case study will
also discuss its impact on the environment and
the community. The study will also highlight the
technology SBR for STP and its practical
results. The visit of this Gwalior plants
elaborates with the TSS intake side and the TSS
at outflow, and practically by seeing the data I
confirm the effectiveness of the STP plant. SBR
technology is energy-efficient and requires less
maintenance compared to other wastewater Figure 1 -- Flow chart of SBR
treatment processes. This is because SBR plants operate in a batch mode, which allows for
greater flexibility and control over the treatment process. Additionally, SBR technology can
reduce the amount of sludge produced during treatment, resulting in lower disposal costs and a
more sustainable treatment process overall.

How SBR Technology works:

The SBR (Sequential Batch Reactor) technology is a type of wastewater treatment process used
in Sewage Treatment Plants (STP). The SBR process is a batch process that involves the
following stages:

1. Fill Phase: In this phase, the SBR reactor is filled with the incoming wastewater until it
reaches a predetermined level.

2. Screening Phase: Screening is the process of removing large particles from incoming
wastewater using a
mechanical screen, to
protect downstream
equipment and
improve treatment
efficiency.

3. Grit removal Phase:

Grit removal is the
use of screens or
sedimentation tanks
to remove heavy
solids, such as sand Figure 2Figure
--- Diagrammatic representation
1: SBR Technology inofSTP
SBR Plant
technology
 and gravel, from wastewater before it undergoes biological treatment. The separated grit
is then typically disposed of in a landfill or recycled for use in construction materials.

4. Aeration tank Phase: Aeration tank in STP plants using SBR technology is where
biological treatment occurs through the introduction of oxygen to support the growth of
microorganisms that break down organic matter in wastewater. The aeration process is
typically followed by a settling period, after which the treated water is discharged or
subjected to further treatment.

5. Settle Phase: After the aeration or mixing is stopped, and the wastewater is allowed to
settle. The aerobic microorganisms settle to the bottom of the reactor, forming a sludge
layer, and the treated water remains above the sludge layer.

6. Decant Phase: In this phase, the treated water is decanted or drawn off from the top of
the reactor. This process removes the clear, treated water from the reactor while leaving
the sludge layer undisturbed at the bottom.

7. Idle Phase: After decanting, the reactor remains idle for a specific duration to allow any
remaining sludge to settle. The duration of this phase is dependent on the specific
requirements of the wastewater being treated.

8. Waste Sludge Removal: After the Idle Phase is complete, the remaining sludge is either
removed for further treatment or returned to the reactor for further digestion, depending
on the treatment process.

The SBR technology offers several advantages over other types of wastewater treatment
processes, such as its flexibility to treat a wide range of wastewater quality and quantity, and its
ability to operate in a compact footprint. Additionally, the process can be easily automated and
controlled, which reduces the need for manual intervention. SBR technology has been
increasingly adopted by large-scale wastewater treatment plants across the globe, due to its
versatility, flexibility, and efficiency. The 145 MLD STP plant is a good example of how SBR
technology can treat large volumes of wastewater while achieving high-quality effluent.

Pic 1 --- Entrance of STP plant

 The SBR technology used in the Gwalior 145 MLD STP plant is highly advanced and
automated, with sophisticated control systems and sensors that monitor and regulate the
treatment process. The plant also uses state-of-the-art equipment, such as fine screens, grit
chambers, and sand filters, to ensure that the wastewater is treated to the highest standards.
Overall, the SBR technology used in the Gwalior 145 MLD STP plant is an efficient, reliable,
and cost-effective method for treating wastewater. It is a sustainable solution for meeting the
growing demand for water in the city while protecting the environment and ensuring public
health.

The plant has a treatment capacity of 145 million liters per day (MLD), which is a
significant improvement over the previous plant's capacity of 52 MLD. This increased capacity
has enabled the plant to treat a larger volume of wastewater, which has helped to reduce the
pollution load on the Chambal River, a major source of water for the city.

Pic 2 -- Arial view of STP

The construction of the STP plant was completed in 2020, and the plant was inaugurated
by the Chief Minister of Madhya Pradesh. The plant has been successful in achieving a removal
efficiency of over 95% for organic matter and suspended solids and is contributing significantly
to the conservation of freshwater resources in the region and been used in farming. The SBR for
wastewater treatment. SBR is a type of activated sludge process that treats wastewater in a batch-
wise manner. The SBR technology is highly efficient in treating wastewater and is known for its
flexibility and adaptability to different treatment scenarios.

The SBR technology involves a series of steps, including filling, aeration, settling, and
decanting. During the filling stage, the reactor is filled with wastewater, and during the aeration
stage, oxygen is added to the wastewater to stimulate the growth of microorganisms that break
down the organic matter in the wastewater. After aeration, the wastewater is allowed to settle,
and the clear water is decanted from the top. The settled sludge is then recycled to the next batch
or removed from the system.

Layout Plan of 145 MLD STP Plant:

Geo Location of the plant: 26.259427685279938, 78.1661817

1. Screening:

The first step in the treatment process involves screening the incoming wastewater to
remove large particles and debris. The
wastewater is passed through a series of
screens to remove objects such as plastic
bags, cloth, and other large debris. 2 no’s of
Screen chamber is provided with manually
cleaned bar rack of medium size. Width of
the each screen chamber is 1.6 m and depth Figure 3.1 --- Screening
is 2 m. The bars are rectangular sharp edged
having clear spacing of 25 mm. and inclined at 60⁰ with horizontal.

2. Grit removal:

After screening, the wastewater is passed

through a grit chamber where heavy particles
such as sand and gravel settle to the bottom
due to their weight. Grit chamber with
parshal flume weir is a rectangular tank with
Figure 3.2 --- Grit Removal
4.5 m x 10 m sides and 1.2 m depth.

Figure 3.1—STP 1st Stage --- On Site Drawings and Plans

3. Primary settling:

The wastewater then flows to a primary settling tank, where the remaining suspended
solids, organic matter, and smaller particles
settle to the bottom by gravity. This step helps
in the removal of about 30-35% of total
suspended solids (TSS). Stabilization pond is a
rectangular pond having 655m length, 130m
width and 1.6m depth.
Figure 3.3 --- Primary Settling

4. Aeration:

In this step, the wastewater is transferred to the SBR reactors, where air is pumped in to
provide oxygen to the microorganisms present in the wastewater. These microorganisms
break down the organic
matter in the wastewater
and reduce the biological
oxygen demand (BOD).
This step helps in the
removal of 90-95% of
BOD. There are 6
Ariation Tanks also
known as Basins. Each
basin is marked from 1 to
6. Figure 3.4 – Aeriation from Bottom

5. Settling:

After the aeration process, the wastewater is allowed to settle in the SBR reactors,
allowing the suspended solids
and microorganisms to settle to
the bottom of the reactor. This
step helps in the removal of
remaining suspended solids
and microorganisms, achieving
total suspended solids (TSS)
removal efficiency of over
Figure 3.5 --- Aeriation condition while the tank is filled.
95%.
 Figure 4.2 – STP stage 2nd -- On Site Drawings and Plans

6. Decanting:

Decanting in STP plants using SBR

technology involves the process of
separating treated water from the
settled sludge by draining the clear
water from the
top of the tank
and leaving
the sludge
at the bottom.
The decanting process is typically
automated and timed to ensure that the Figure 3.5 --- water at rest
appropriate amount of treated water is discharged while minimizing the loss of solids. In
short, removal of the top layer of the water after settlement of 4 to 6 hrs of the water in
the basin.
7. Tertiary treatment: The water collected after
decanting is then subjected to tertiary treatment. In this
STP plant also they use chlorination in teritary
treatment process. Chlorination is widely used
disinfection method applied in the last stages of
sewage treatment. As a strong oxidizer, chlorine reacts
with organic compounds, with negative effects on
human health and the environment. In the disinfection
step, the treated water is disinfected using chlorine, to
kill any growth of the bacterias or any other harmful.
Then the chlorinated water is passed through the open
long channels before supplying it for agriculture use. Figure 3.6 --- Chlorine channel Process

Figure 4.3 – STP stage 3rd -- On Site Drawings and Plans

8. Sludge treatment: The sludge generated during the treatment process is treated
separately in sludge treatment facilities,
which include sludge thickeners and
dewatering units. The treated sludge is then
disposed of or used as a fertilizer. In the
Plant, the sludge from the basin comes to the
sludge thickener, and from there, after processing the sludge the water is sent back to the
basin and the sludge is pumped to the Centrifuge. The centrifuge separates more water
from the sludge. Then the sludge is converted to manure.
 Figure 4.2 – STP stage 4th -- On Site Drawings and Plans

Some more picks of the Plant –

Figure 6.1 --- Separated Grit

Figure 6.2 --- Blower unit

Differences between SBR

and conventional
continuous-flow activated Figure 6.4 --- Centrifuge

sludge system
Figure 6.3 --- Sludge Thickener
 1. Aeration and sedimentation/clarification processes are carried out in both systems. In
conventional plants, the processes are carried out simultaneously in separate tanks. In
SBR operation the processes are carried out sequentially in the same tank.

2. SBR system can be designed with the ability to treat a wide range of influent volumes
whereas the continuous system is based upon a fixed influent flow rate. Thus, there is a
degree of flexibility associated with working in a time rather than in a space sequence.

Conclusion

The plant's advanced Sequential Batch Reactor (SBR) technology has proven to be highly
efficient in treating wastewater. The treated water meets the Central Pollution Control Board's
(CPCB) discharge standards for reuse in irrigation, landscaping, and other non-potable uses. The
plant has also reduced the biochemical oxygen demand (BOD) and total suspended solids (TSS)
levels in the wastewater, which are key indicators of water quality. The treated water is used in
the agriculture purpose by the local body and the sludge is after centrifuge is used as the manure
by providing it to the farmers and the gardners.

The plant has been designed with advanced treatment processes, such as fine screening, grit
removal, and sand filtration, which have helped to remove pollutants and other impurities from
the wastewater.

Overall, the Gwalior 145 MLD STP plant has been successful in achieving its goals of treating
wastewater to meet the city's growing water demand while protecting the environment and
ensuring public health. The plant is a sustainable solution for managing wastewater in the city
and serves as a model for other cities in India and around the world.

References

1. Gupta EA. CASE STUDY ON VARIOUS WASTE PROCESSING COMPOSTING

TECHNIQUE ’ S PREVAILING IN INDIA. International Journal of Education, Modern
Management, Applied Science & Social Science (IJEMMASSS). 2020;02(04):123-128.
https://www.inspirajournals.com/uploads/Issues/159723087.pdf

2. Gupta EA. Role of Bio Gas Plant for Empowering the Women Communities in Rural Area of
India. AIJRA. 2020;V(III):12.1-12.4. www.ijcms2015.co

3. David B, Paolo P, Edition S. Biohythane Production From Food Wastes Microalgae-based

wastewater treat- ment and utilization of microalgae bio- mass. Published online 2022.

4. Gupta EA. Case Study on Bio Gas Plant Installed at Hingoniya Gaushala , Jaipur
( Rajasthan ), by Sai Nath Renewable Energy Pvt . Ltd . AIJRA. 2021;VI(I):1-10.
www.ijcms2015.co
5. Gupta EA, Singhal S. Case Study on Plastic Pollution – Reuse , Reduce and Recycling
Process and Methods. THE RESEARCH JOURNAL (TRJ): A UNIT OF I2OR. 2021;7(3):1-7.
theresearchjournal.net

6. Gupta EA, Sharda N. CASE STUDY ON OXYGEN MANUFACTURING AND

BOTTLING PROCESS TO HELP THE SOCIETY IN THIS PANDEMIC SITUATION ,
COVID – 19. International Journal of Advanced Research in Commerce, Management &
Social Science (IJARCMSS). 2021;04(02):159-167.

7. Gupta EA, Jain dr anupam. CASE STUDY ON PROJECT TO TREAT 100 TON
MUNICIPAL BIO DEGRADABLE WASTE IN, JAIPUR, RAJASTHAN Er Alok Gupta
Director, Sai Nath Renewable Energy Pvt. Ltd., Jaipur, Rajasthan, India. Dr. Anupam Jain
Associate Professor ABST, LBS PG College, Jaipur, Rajasthan,. NIU International Journal
of Human Rights. 2021;8(V):123-132.

8. Jain A, Gupta EA. Case Study Case Study on Environment Protection through Training in
Biomining and Bio Remediation – Legacy Waste Treatment. IJTD. 2021;51(1):96-102.

9. Clair. N. Sawyer “Chemistry for Environmental engineering and Science”

10. CPHEEO manual 2013 (Central Public Health and Environmental Engineering
Organization).

11. S. K. Garg Sewage Disposal “(Environmental engineering vol 2)”

12. Metcalf & Eddy “Wastewater Engineering”.

13. “Performance evaluation of Sewage treatment Plant Nesapakkam at Chennai city” by K.

Sundara kumar, P. Sundara Kumar, Dr. M.J Ratnakanth Babu.

14. “ Design and Performance evaluation of Sewage treatment Plant-D at Tirumala in Chittoor
district of Andhra Pradesh” by ISSN:2229-5518 (Author G. Chandrakant, P. Jaswanth, S
Teja Reddy, G kiranmai).

15. Arceivala Soli J. and Asolekar S. R. (2006), ”Wastewater Treatment for pollution Control
and reuse” third edition, TMH, New Delhi.

16. Vatech Wabag Ltd., Jaipur, Records of plant operation at STP site office, Delawas, Jaipur.

17.MoEF (2009). Compendium prepared by IIT Kanpur for NRCD- MOEF on “Conventional
ASP based STPs under YAP- Allahabd” pp 60-80.

18. Paper presented in 46th annual convention of IWWA at Banglore India, in Jan-2014 by the
authors.