Studies have projected that India’s vantage point in the coming decades would be cities full of people, which means immense human potential, opportunities and capital resources. There is a huge scope to improve the current conditions of cities in India, making a safe and secure urban life ought to be built on conscious decisions taken by all stakeholders.  

At present, the cities — small or semi-urban centres, with or without industrial hotspots,— in countries like India or elsewhere really cannot afford to miss the opportunities to improve the minimum level of urban amenities and ambiance for providing a safe and secure living for all. The aim of future cities ought to be embedded in the aspirations of people with their participation and inclusive nature of dialogues between the government at the local level and the people. 

During the monsoon seasons, many cities in India witness water logging mainly due to the failure of storm-water drainage systems which are either dysfunctional or clogged with all kinds of solid waste generated by residents, industrial and medical establishments, etc. The issues of septage management systems were completely ignored for decades, despite the development of promising indigenous technologies that are not just affordable but highly decentralised in approach making them more sustainable.

However, crises of the past and now with COVID-19, policymakers seem to have missed the imperative to focus on sound public policies to address the core issues of cities.

According to the Union Ministry of Urban Development’s National Policy on Faecal Sludge and Septage Management, 2017 (NPFSSM), about 47 per cent of urban households depend on on-site systems of toilet waste management in India. Around 62.5 per cent of toilet waste in urban India is untreated or partially treated, and a major part of this waste is from on-site systems. The number is even higher in Tamil Nadu with 55 per cent of the population (as per Census 2011) continue to dispose of toilet waste into septic tanks — many of which are not designed properly — and hence sewage does not get treated effectively, resulting in faecal contamination and diseases.

Tamil Nadu is the most urbanised State in India with about 50 percent of people living in urban areas. According to the Government of Tamil Nadu’s “Operative Guidelines for Septage Management for Local Bodies in Tamil Nadu (2017), many institutions, commercial establishments, high-rise buildings and households let sewage water into storm-water drains illegally and regulators are unable to make these offenders comply. In areas un-served by sewer systems, sewage collected in underground tanks is dumped into water bodies in and around cities, thereby contaminating groundwater and resulting in environmental degradation.

Further, the practice of dumping of sewage at the closest point from where it is collected has been rampant across the country. Moreover, so far, only about 35 percent of Tamil Nadu’s urban population is covered by Underground Sewage Systems (UGSs). Indeed, many local bodies cannot create and manage assets for the treatment of liquid waste as these involve large investments and long gestation periods. Besides, maintenance of the established treatment systems is another big challenge.

Moreover, there were also incidents of underutilisation and dysfunction of existing sewage treatment plants (STPs) and disposal of untreated waste into freshwater bodies. Even though there exist stringent regulations, untreated waste from on-site systems are let into undesignated areas like open drains, water bodies, empty land, river, streams, etc. leading to health hazards, groundwater pollution and faecal contamination of the water supply.

Therefore, innovative approaches are needed to solve key urban issues such as hygiene and sanitation by adopting sustainable and cost-effective technology. Though recent years have witnessed massive awareness about hygiene and sanitation through Swachh Bharat Mission, innovative and sustainable approaches to adopt the indigenous technology on a larger scale were not given adequate focus and attention.

A clean and green environment is not something the government alone is responsible to make; every individual citizen of the country should be a part of it. We need to encourage a decentralised, technology-driven and eco-friendly model with individual ownership-based solutions for on-site sanitation systems built independently by residents, institutions, industries, etc. These innovative designs have to be based on an individual owner’s budget and space available, rather than adhering to single bureaucratic standards and safety norms which make the entire system cumbersome and outdated, serving no purpose at all.

Biodigester is Antidote

The Government of India’s Defence Research and Development Organisation (DRDO) had developed the eco-friendly Biodigester technology in 2014 and transferred the technology to several companies all over the country. A total of 56 companies were given this technology license, but not all license holders were effectively working to improve the filthy urban space to provide a safe and secure environment in a cost-effective manner.

Biodigester has high potential and has been diligently developed with indigenous technology and tested. Few companies, including some from the State of Tamil Nadu, are now the leading makers of Biodigester in India with large-scale production capacities. However, despite its high potential, it is yet to be revolutionised across all sectors of the economy. The urban planners have either heard about it or ignore it or play with vested interests to prevent venturing into resolving the cities’ core issues.

The Biodigester is now being used on a large scale by the Indian Railways and the armed forces, besides others. Several thousands of Biodigester tanks and bio-toilets are installed across the country.

  • The experience shows that Biodigester is eco-friendly and can be built with less than 30 per cent of the conventional Septic Tank area used. Till now, thousands of units are installed in various sectors across the country.
  • The size of a bio septic tank is approximately one-third of the conventional septic tank, hence material cost and space required for building it are much lower.
  • The maintenance cost was zero for lifetime use. Low-cost single house Biodigester was also designed for rural areas where it requires little space, generates environment-friendly safe effluent, and does not require any maintenance.
  • Field experiences reveal that in the Biodigester more than 90 per cent of pathogens are killed and hence it is hygienic and contributes to a healthy environment. Also, more than 90 per cent of waste was decomposed.
  • In contrast, in conventional toilets, only 30 percent of human waste is degraded and the other 70 per cent remains in the septic tank and produces toxic pollution.
  • In a Biodigester, human waste up to 99 per cent gets digested by Anaerobic Microbial Inoculum filled in the bio-tank and gets converted into reusable water and methane gas.

Of course, some criticisms challenge the efficacy of Biodigester technology based on the micro-level field studies (Philip et al. 2020). However, institutions like the Centre for Science and Environment (2016 and 2019) have supported the technology based on several national-level best practices and comparative studies which paved breaking away from the conventional systems.

The Niti Aayog in its Report on [email protected] 75 Strategy for New India (2018) adopted a national strategy “to reduce the cost and time incurred on laying sewage pipelines and constructing sewage treatment plants, SBM should encourage the use of bio-digester technology”; and it is stated that “the use of bio-digester toilets, a technology licensed by the Defence Research and Development Organisation (DRDO), maybe expeditiously considered for nationwide implementation. It can be a complete game-changer as, if successful, it can do away with the need to have sewers and sewage treatment plants.”

The Union Budget 2021-2022 has given a huge impetus to launch the Urban Swachh Bharat Mission2.0 by allocating Rs 1,41,678 crore over five years (2021-2026) to address the “faecal sludge management and waste water treatment, source segregation of garbage, reduction in single-use plastic, reduction in air pollution by effectively managing waste from construction-and-demolition activities and bio-remediation of all legacy dump sites”.

Therefore, every state government should take necessary steps to clean up cities and urban centres to make them safe and secure for living. Also, governments should issue appropriate orders or GOs stipulating the mandatory norms that any new building, both public and private, with a minimum 3000 sqft and above should have Biodigester of higher quality to process the entire toilet waste in a decentralised manner. These new norms, if passed through state governments’ orders, with a unified independent execution agency, will surely enable not only creating awareness about hygiene and sanitation but also to help create safe and secure urban ecosystems to maintain a clean and green environment.

Views expressed by the author are personal and need not reflect or represent the views of Centre for Public Policy Research


  1. Philip, Ligy, K. Kalaivani, Praveen Rosario, Vamsi Krishna, and S. SriShalini. 2020. “Performance Evaluation of Anaerobic Baffled Biodigester for Treatment of Black Water.”Current Science118 (8).
  2. “Mainstreaming Citywide Sanitation Opportunities & Challenges for Excreta Management with Focus On “Bio Digester.” 2016. Presentation made in CSE’s Seminar.
  3. “DRDO Bio-Digester Technology Affordable and Safe Onsite Treatment System for Urban and Rural”. 2019. Presentation made in CSE’s Seminar.
Chandrasekaran Balakrishnan
Chandrasekaran Balakrishnan
Chandrasekaran Balakrishnan is Research Fellow (Urban Eco-system and Skill Development) with CPPR. His areas of research interest are economics of education, vocational education and skills development, economic reforms, liberal vision for India, water management, regional development, and city development. Chandrasekaran has an MA in Economics (University of Madras) and an MPhil in Social Sciences (Devi Ahilya Vishwavidyalaya University, Indore).

Leave a Reply

Your email address will not be published. Required fields are marked *