What Is A Sewage Treatment Plant and How Does It Work? 

The modern technology solution to treat sewage and make it reusable for further use is what we call a sewage treatment plant (STP). In other words, a type of wastewater treatment system it is!

Perhaps, it is one of the salient mechanisms to conserve the finite water resource on earth, and simultaneously conduct other activities that require water, such as gardening, irrigation, construction, etc.

But, while about 72,368 MLD (million liters per day) wastewater gets generated daily, the treatment covers only 20,235 MLD

Well, it is an indication that we lack awareness about STP. It is a sign that we are yet to utilize this modern technology in every industry, educational and healthcare institution, hotel, commercial building, and housing society across the country.

How about you fill your knowledge gap by exploring all about STP this time? If so, do not hesitate to read below!

What is the main objective of a sewage treatment plant?

The wastewater that gets released from household, commercial, or industrial sources every day contains harmful substances, such as suspended solids, biodegradable organic, refractory organics, pathogens, etc. So, if this water is left untreated, it can cause –

  • Biological degradation,
  • Deposition of sludge in the aquatic environment, creating an anaerobic condition, and 
  • Eutrophication, where excessive nutrients in the water body stimulate a dense growth of plants and algae.

In fact, even when you intend to reuse this water for several commercial, domestic, and industrial purposes, untreated wastewater can affect public health and safety. It opens up the path for harmful pathogens to breed and spread diseases.

Hence, a sewage treatment plant takes the stage with the aim to remove contaminants from the wastewater and ensure that the reusable water is much cleaner and environmentally-friendly. It eliminates all the above possibilities, and makes this world a better place to live in!

What are the main components of a sewage treatment plant?

sewage treatment plant components

A sewage treatment plant typically holds four componential systems – 

  • The mechanical processing system,
  • The physical therapy system,
  • The chemical treatment system, and
  • The biological treatment system.

While the mechanical processing system includes filtration, homogenous baths, and oil separation equipment, the physical therapy system involves sedimentation and flotation apparatus.


While the chemical treatment system entails instruments for undertaking oxidation and chlorination, the biological treatment system constitutes mechanisms to activate sludge and perform secondary aeration.

Note that each componential system, and each part has a specific function in the process of wastewater treatment. 

What are the operational stages of a sewage treatment plant?

stages of water in sewage treatment plant

A sewage treatment plant operates in three main stages: the primary treatment stage, secondary treatments stage, and tertiary treatment stage.

1) Primary Treatment: The Stage of Contaminant Separation!

It is the stage where the STP seeks to separate inorganic solids and other toxic substances from the wastewater, and reduce the impact of pollutants from it. The primary treatment stage also works to homogenize the sewage, especially during a shared sewage network or extensive pouring of industrial wastewater into this chamber.

  • The filter placed at the beginning of the chamber, functions to seize the large solid materials from the sewage. It may be a fine or coarse filter, depending on the type of sewage treatment plant you install.
  • Then comes the shredding devices! They break the solid materials such as stones present in the wastewater.
  • Next are the sand precipitators that seize fine gravel materials and sand. They reduce the volume of sediments existing in the sedimentation basins.
  • Furthermore, the adjustment basins adjust the intensity of sewage water that arrives in the STP.
  • On the same note, the flotation ponds begin their action to remove grease and oil from the sewage water.
  • Last but not the least, the sedimentation basins intend to completely remove the fine solids that act as a burden to the biological treatment chambers. Such equipment can be rectangular or circular.

2) Secondary Treatment: The Stage of Biological Treatment!  

It is the second stage of the functioning of a sewage treatment plant, where the oxidization process of various organic materials in the sewage water takes place. As a result, these substances turn into biomass and stable compounds, and the sewage water gets free from organic pollutants.

  • Here, different aeration tanks, such as conventional, extended aeration, split feeding, contact stabilization, and full mixing tanks, operate together to activate sludge.
  • Then appears the ventilated ponds, which provide oxygen, and keep the aerobic organisms suspended, so they can effectively decompose the organic materials in the sewage.
  • Next comes the biological filters! These are where the bacterial colonies break down the nutrients in the sewage, such asnitrogen or phosphorous-containing compounds.
  • Further, lay a rotating biological disk that rotates to accelerate the oxidization process.
  • And the stabilization ponds act to stabilize the organic materials in the sewage via natural processes, including sunlight, atmospheric oxygen, nutrients, and so forth.   

3) Tertiary Treatment: The Stage to Make Water Ready for Reuse and Its Discharge!

It is the final stage of this multi-stage wastewater treatment in a sewage treatment plant. During this stage, the final filtration process takes place. In case any contaminant remains in the treated water, despite the active operations of the primary and secondary treatment stages, the tertiary treatment runs a check and removes them. Multiple methods are used in this, from disinfection to dichlorination, and vary from one STP type to another.

  • The tertiary filtration technology wipes out particulate particles through a porous medium.
  • The membrane technology eliminates a wide range of wastes before the delivery of effluent water.
  • The advanced oxidization system adds ozone to the water to kill bacteria and decompose organic pollutants.

What are the benefits of a sewage treatment plant?

Modern technology such as the STP, undoubtedly, provides multiple benefits to people’s lives and our ecosystem. Now, you must be wondering what those benefits are! So, here they go.

1) An STP is a high-performing wastewater treatment system.

If you are looking forward to having a proven technology that offers reliable wastewater management and treatment systems, it is none other than a sewage treatment plant.

It is because if you use such a technology, it is unlikely for you to encounter any issue. In fact, an STP works much better than others, such as a septic tank, an ascendant flow, electro-oxidation, a reed bed, and more.

Indeed, a high-performing STP can empower homes, businesses, and communities to enjoy improved safety and derive abundant reusable water for domestic, industrial, or commercial endeavors.

2) STPs are easy to install and maintain.

Sometimes, installing and maintaining heavy and complex wastewater treatment systems become challenging, specifically on compact sites. And sometimes, such installation or maintenance requires too much cost and labor. Not anymore if you opt for a sewage treatment plant!

Such technology is simple and easy to install and maintain. Of course, you would require professionals for that. But you won’t need to involve many of them!

You can position an STP in various places, be it above the ground or below! Additionally, the installation process is quick too! 

3) Advanced urban STP consumes lower energy.

It is true that most STPs require a constant supply of electricity, and that too in extensive amounts. But not when you use the advanced urban STPs! That’s right! This particular STP type uses much lower energy to conduct wastewater treatment.

They lay designed in a way that fits urban sites and demands. They lay designed with environmental sustainability in mind!

So, today, where energy consumption has grown into a crucial concern, getting to treat wastewater at a nominal energy extraction yet not deteriorating the output efficiency is a rare boon.

4) STPs are cost-effective compared to other wastewater treatment technologies.

While STPs hold a long-life span, even up to around 35 years or more, they are certainly cost-effective.

Moreover, in using a sewage treatment plant, all you need to pay for are – the installation, energy, and annual maintenance. However, as the installation and maintenance processes are simple and require lesser effort, the expenses are less! There is no additional operational cost, in some cases.

On top of that, the lower energy usage, in the case of some advanced urban STP, makes it easier for you to secure a cost cut!

And over time, such benefits get reflected clearly.

5) STPs comply with the governmental standard set for the emission of pollutants.

When it comes to compliance factors, sewage treatment plants adhere to the latest standard set in terms of the emission of pollutants. The governmental bodies that set these specifications are CPCB (Central Pollution Control Board) and MoEF&CC (Ministry of Environment, Forest, and Climate Change of India).

So, you can get relief concerning the delivery of safer water from this wastewater treatment system.

If you desire a better pedigree, you can even check whether the STP you install is accredited or certified by ISO. When it is so, you can stay assured that the recycled water you receive is devoid of pollutants and pathogens.

6) Many STPs are modular and scalable.

Another significant benefit of a sewage treatment plant is, no wonder, its modular and scalable design.  It is a modern and advanced version of STP that encompasses a higher concentration of bacteria for wastewater treatment.

On top of that, such state-of-the-art technology comes with custom designs! Thus, you can ask the STP provider to increase the size of this plant, making it accommodative for more wastewater treatment.  These STPs have a higher effluent loading rate that can enhance the overall system footprint.

You can get various types of STPs, from an AC-SED system to an NBF system and so on!

How can you use the recycled water generated by a sewage treatment plant?

You can use the treated water from an STP for multiple purposes, some of them are: 

Where can you install an STP, and where can’t you, as per CPCB guidelines?

According to CPCB guidelines, you can install a sewage treatment plant  –

  • 250 meters away from a water body,
  • Underneath any driveway,
  • Beneath play areas,
  • Beneath clubhouse, or
  • A little far from the residence.

CPCB recommends not installing an STP in any building’s basement because that may cause complications during rain flooding or create too much noise.

Final Thoughts:

Hey, are you still here, learning all about STPs?

Well, this is a wrap-up for the time, and we shall come back soon with other wastewater management solutions. We hope the article served your purpose.

You can now grow awareness among your fellow mates regarding this modern wastewater treatment technology and encourage residential neighborhoods, institutions, commercial entities, and others to install it.

Always remember that the more sewage and wastewater gets treated, the more you get to conserve this natural resource, and similarly use it to the fullest! So, are you not up for it?



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Dr. Basava R D

Independent Director

Dr. Basava Raju Dumpala is a senior management professional who combines corporate leadership experience with an understanding of interpersonal dynamics. He has over 35 years’ experience with Larsen & Toubro (L&T). As a member of the top management team of L&T, Dr. Raju helmed several key business and corporate functions. He was the Executive Vice President and Advisor to the Chairman, L&T. Among the business roles, Dr Raju handled several sales and marketing functions. He consolidated the realty business portfolio of the company as the Director & Head of L&T Realty Limited. He led negotiations with the trade unions for wage settlements and to maintain harmonious and productive working environment at the company’s campuses.

He has taught Industrial Marketing at National Institute of Industrial Engineering and S P Jain Institute of Management and Research, Mumbai. Dr. Raju’s rich diversity of experience gave him a ring-side view of the top management and enabled him to acquire a thorough understanding of the leadership psyche. As an Executive Coach, he applies this understanding to help business executives realize their true potential. He has coached and mentored several senior executives from manufacturing, infrastructure, technology, finance and realty sectors.

Aparajita Agrawal

Independent Director

Ms. Agrawal is a management professional with 18 years of experience in impact investing, entrepreneurship development, and network building. Ms. Aparajita Agrawal has expertise in sectors such as innovative finance, microfinance, livelihoods, education and women entrepreneurship. Presently, she is involved in consulting assignments to further social entrepreneurship, innovative financing and impact investing. Her last full-time institutional role was the Country Director for a British Charity straddled philanthropy and impact investments. Prior to this, she has 12+ years of progressive experience as Co-founder and Director at Intellecap Advisory Services Pvt. Ltd., a leading global development advisory firm in India where she co-created new business verticals, service lines, managed profit centres and expanded the firm’s business in new geographies. She successfully led global engagements through rapid network building, fund-raising, regional expansion and complex stakeholder management.


Anil Sharma

Independent Director
Anil Sharma graduated from Delhi University in Economics. He has a Post Graduate Diploma in Advertising and Communication from National Institute of Advertising, with specialization in Public Relations. He has worked in various firms in the areas of advertisement and public relations from 1998 to 2011. He, later, joined Havells India Limited as Head – Corporate Communications, CSR & Sustainability in May 2012. Mr. Sharma founded ThinkQue Consulting in August 2021 to provide consulting services in marketing, CSR and sustainability.

Sanjay Gangwar

Independent Director
Sanjay Kr. Gangwar is a commerce graduate, B. Com (Hons) from Delhi University and qualified as a Chartered Accountant in 1996. He is a Fellow member of ICAI (FCA) and has also completed post qualification course of ICAI on Information System Audits DISA (ICA) in 2004. He has over two decades of varied experience with large corporates and as a practicing CA. He has worked with corporates like Times Group and Tata Telecommunications Ltd. (formerly known as VSNL) in various capacities and has been on the Board of investment company of Times Group as a nominee director. As a practicing CA, he has worked with Aiyar & Co., Chartered Accountants, New Delhi and with S. C. Vasudeva & Co., New Delhi. His working experience covers various facets of finance function including Corporate Structuring, Business Re-structuring, Tax Planning & Risk Mitigation, GST structuring & implementation, Quarterly/ Half-yearly/ Annual Closings, Statutory, Management, Tax & Bank Audits, Assessments, Appeals, etc. He is currently Managing Partner of S K G P G & Associates, Chartered Accountants, Lucknow which he established in 2019 and continues to handle tax matters of Times Group apart from other clients.

Kamalesh Sekhar

Independent Director
Kamalesh is the Director of Three D Management Services, a Boutique Business Advisory firm advising Family Businesses and Closely held Private Companies on Strategy, M&A, Fund Raising, and Market entry. Prior to his entrepreneurial journey, Kamalesh played leadership roles across Marketing & Business Strategy for ArcelorMittal in Mexico. He also served with Asian Paints and PricewaterhouseCoopers . Kamlesh is a Chartered Accountant and also an MBA from the Indian School of Business.

TV Rama Krishna

CFO & Executive Director
Mr. T V Rama Krishna is the Executive Director of our Company. He completed Bachelor Degree in Commerce from Nagarjuna University, Post-Graduation Diploma in Industrial Relations and Personnel Management and Post-Graduation Diploma in Information Management. Having more than 24 years of functional experience in the field of Finance & Accounts, he is instrumental in Fund Management, Financial Planning, Budgeting, MIS, Financial Reporting, Auditing, Direct and Indirect Taxation, Statutory Compliance and Company Law Matters. His functional responsibility involves handling the overall financial activity of our Company, supervising accounting staff, overseeing internal controls, implementing fund-raising strategies, developing financial strategy, monitoring cash flow etc.

Akhilesh Tripathi

Executive Director
Mr. Akhilesh Kumar Tripathi is the Executive Director of our Company. He is one of the founding members of our Company. He completed his Diploma in Automobile Engineering from Board of Technical Examinations, Maharashtra State. Prior to joining this company, he has almost two decades of experience in automobile, production and operational planning in renowned companies such as Bajaj Auto Ltd, TVS Motor etc. He has been an executive board member of the Company since its incorporation and looks after day-to-day technical and managerial aspects of the Company

Vishal Murarka

CEO & Executive Director

Vishal Murarka has over 20 years of rich and varied experience covering a range of industries across technology, infrastructure and real-estate, and is the CEO of Banka BioLoo.He collaborated in multilingual environment across markets in Asia, Europe and the US. Vishal has been part of Banka BioLoo since 2012.

He has been instrumental in the setup of the company, first as an investor and then as a Non-Executive Director. Over the years, he brought in corporate governance best practices and spearheaded strategy and capital raising. Prior to Banka BioLoo, Vishal spent four years in Seoul, South Korea, working for a French MNC, where he led the company’s growth in Korea, Taiwan and China. Vishal relocated to India in 2005 and served at TATA Group, Larsen & Toubro (L&T) and Piramal Group in multiple leadership positions. At L&T, he was part of the corporate strategy team leading a variety of projects across the infrastructure domain covering growth and exits. He also spearheaded the setup of L&T’s real-estate business, as Head of Strategy and Business Development. Vishal was instrumental in multiple, multi-billion dollar real-estate transactions. At Piramal, he led Business Strategy, P&L, and owned budgets and annual operating plans. He was instrumental in the closure of a multi-billion dollar transaction and turnaround of Piramal’s real-estate development projects. Vishal is a growth specialist and he earned his MBA in Marketing & Finance from the Indian School of Business (ISB). In addition, he holds an undergraduate degree in engineering.

Sanjay Banka

Executive Chairman

Sanjay Banka is the Executive Chairman of Banka BioLoo. He is a strong propagator of Sustainable Development Goal 6, the water and sanitation global goal. With academic background in sciences, humanities, human rights, law and business management, he has a strong understanding of society, economy and the polity, along with technology and sustainable development, with a focus on water, sanitation and hygiene (WaSH).

Professionally, he has worked in family business, start-ups, MNCs, and co-founded Banka BioLoo. Well-versed with humanitarian problems, primarily issues related to water and sanitation, he puts his best foot forward in helping provide eco-friendly and sustainable water and sanitation solutions. He is considered an expert on sustainable WaSH; and regularly participates in and contributes to the national and global WaSH discourse, advocacy and action. He has a strong understanding of, and has worked across various WaSH themes such as WaSH in schools (WinS), WaSH in the workplace (WaSH4Work), WaSH in healthcare facilities (WaSHinHCF), among others. He is a prolific writer and speaker, and has authored many a piece on sustainable WaSH; as also spoken extensively, including at the UN. He, strongly, believes in partnerships as a basis for sustainable development. Governments, civil society, academia and businesses should work in harmony for the greater good of the society. He holds several positions in national and international organizations, including the most recent Founder President of Sustainable Sanitation Industry Association.

Namita Banka

Founder & MD

Mrs. Namita Banka is the Managing Director and the founding members of Banka BioLoo. She completed her Bachelor of Science (Home Science) from University of Delhi and also completed her Diploma in Jewellery Designing, Mfg. & Appraising from Indian Diamond Institute, Surat. Mrs. Namita Banka has 8 years of experience in the field of diamond Jewellery. In 2008, she began her Entrepreneur venture of BioLoo in proprietor concern, later on which was acquired by our Company. She has been the main guiding force behind the growth and business strategy of our Company. She has now almost a decade of sanitation industry experience and has been instrumental in the consistent growth of our Company’s performance.

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