Theme 1 — Flagship Research Programme
From a pioneering idea to a platform for future sanitation
This programme is the Dr. Bindeshwar Pathak Research Foundation's flagship research theme because it originates in the innovation that defined Sulabh International's founding mission.
In 1968, Dr. Bindeshwar Pathak developed the two-pit pour-flush ecological compost toilet — an affordable, low-water system that safely contains and treats human waste on site, without depending on a conventional sewer network. By replacing insanitary dry latrines, this technology also helped remove the need for the manual handling of human excreta — one of the most degrading practices imposed on marginalised communities in India.
More than five decades later, Sulabh International operates more than 1.69 million household toilets, 10,746 public toilet complexes, 20,207 school toilets and 2,454 slum community toilets. This gives DBPRF access to an exceptional field-research network that no laboratory or demonstration project can replicate.
The central research question of this programme is: Which sanitation system is appropriate for a particular place, population and environmental condition — and does it safely manage human waste throughout its operating life?
This programme does not begin with a preferred technology. It begins with the context.
A toilet cannot be considered successful merely because the structure has been constructed. Its safety depends on what happens to faeces and urine, flush water, bathing and handwashing water, cleaning water, menstrual and solid waste, accumulated sludge and treated outputs.
The programme studies the complete physical and environmental system:
Location and demand → facility configuration → water and waste flows → containment and treatment → reuse or safe disposal
Drawing on Sulabh International's experience across household toilets, schools, public conveniences and community sanitation systems, DBPRF will compare technologies under actual operating conditions — examining hydraulic and pollutant loading, land and water requirements, pathogen reduction, groundwater protection, sludge accumulation, energy use, treatment reliability, climate resilience and the quality of treated outputs.
Low-water, affordable and locally maintainable on-site systems for homes and settlements beyond sewer networks. Research will examine whether two pits are correctly constructed and connected, how long pits take to fill, what pathogens remain after different resting periods, whether liquid effluent reaches wells or shallow groundwater, and what happens when pits are incorrectly connected or simultaneously used.
Child-friendly and gender-responsive WASH systems, with research on usability, menstrual hygiene, water availability, maintenance and behaviour change. Schools operate during defined hours but have distinctive requirements — sharp use peaks during breaks, age-specific toilet design, gender segregation, menstrual-health requirements, long closures during holidays and limited O&M budgets. Research will focus on water balance, pit or tank sizing, loading during breaks, closure effects and safe treatment.
Safe and inclusive systems for high-footfall locations, with research on treatment performance, operator capacity, service quality, digital monitoring and resource recovery. A standard public convenience may serve approximately 600–1,000 people per day. Festival and peak periods can cause septic overflow and emergency desludging — research must therefore develop peak-load design factors, not rely only on average use.
Sulabh's foundational technology requires a major contemporary evidence programme — testing actual fill times, resting periods observed in practice, pathogen and helminth survival, moisture and temperature effects, pit-switching behaviour, groundwater conditions, detergent and disinfectant effects, flooding and seasonal saturation, and safe emptying practices.
Current design frequently uses average daily footfall. DBPRF will develop evidence on maximum hourly use, festival loading, queue and demand peaks, water demand, wastewater strength, treatment shock loading, sludge accumulation and recovery after overload.
Public toilets with bathing facilities can generate much more greywater than blackwater. Mixing both streams may increase tank volume, dilute biological treatment and shorten retention time. DBPRF will test whether source separation enables smaller blackwater-treatment systems, local greywater reuse, lower freshwater demand and reduced tanker requirements.
Research will investigate compact systems specifically for dense public sites where land is unavailable for large septic tanks, soak areas or treatment units.
Research will investigate movement of pit and septic-tank effluent, microbial contamination near facilities, risk to shallow wells, effects of rainfall and flooding, nutrient loading and soil attenuation — with particular attention to liquid effluent pathways that can account for significant pathogen release.
Research will examine flood ingress, pit inundation, high groundwater, drought and reduced flushing, extreme heat, power failure, heavy rainfall and drain backflow, and temporary population displacement.
Statements such as “pathogen-free”, “zero discharge” or “safe for agriculture” should only be made when supported by defined testing methods, accredited laboratories, adequate sampling frequency, seasonal and peak-load evidence and transparent reporting of failures.
World Health Organization. (2018). Guidelines on Sanitation and Health.
Provides the overarching public-health framework for safe sanitation systems and services.
View guidelinesWorld Health Organization. (2022). Sanitation Safety Planning: Manual for Step-by-Step Risk Management for Safely Managed Sanitation Systems, second edition.
View manualWorld Health Organization. (2024). Sanitation Inspections: User Guide and Inspection Packages.
Provides standardised field tools for identifying risks around sanitation systems.
View guideWorld Bank. Citywide Inclusive Sanitation Initiative.
Establishes the principle of combining onsite, sewered, centralised and decentralised systems according to context and service outcomes.
View sourceInternational Organization for Standardization. (2025). ISO 30500:2025 — Non-Sewered Sanitation Systems: Prefabricated Integrated Treatment Units — General Safety and Performance Requirements for Design and Testing.
View standardWorld Health Organization and UNICEF. (2022). WASH FIT: A Practical Guide for Improving Quality of Care through Water, Sanitation and Hygiene in Health Care Facilities, second edition.
View guideGlobal Sanitation Center of Excellence, IIT Palakkad, and International Water Association. (2026). Second International Conference on Non-Sewered Sanitation Systems — ICNSS 2026.
View conferenceMinistry of Housing and Urban Affairs. (2021). Swachh Bharat Mission–Urban 2.0 Operational Guidelines.
Covers household, public and community toilets, water arrangements, onsite sanitation and faecal-sludge management.
View guidelinesCentral Public Health and Environmental Engineering Organisation. (2018). Advisory on Public and Community Toilets.
View advisoryCentral Public Health and Environmental Engineering Organisation. (2020). Advisory on On-Site and Off-Site Sewage Management Practices.
View advisoryMinistry of Urban Development. (2017). National Policy on Faecal Sludge and Septage Management.
View policyNITI Aayog and National Faecal Sludge and Septage Management Alliance. (2021). Faecal Sludge and Septage Management in Urban Areas: Service and Business Models.
View reportDepartment of Drinking Water and Sanitation. (2020). Operational Guidance on Selection and Construction of Twin-Pit Toilets.
View guidanceDevaraj, R., et al. (2021). Planning Fecal Sludge Management Systems: Challenges Observed in a Small Town in Southern India. Journal of Environmental Management, 281, 111811.
View articleManga, M., et al. (2022). Public Health Performance of Sanitation Technologies in Tamil Nadu, India: Initial Perspectives Based on E. coli Release. International Journal of Hygiene and Environmental Health, 243, 113987.
View articleHussain, F., et al. (2017). Advantages and Limitations for Users of Double-Pit Pour-Flush Latrines: A Qualitative Study in Rural Bangladesh. BMC Public Health, 17, 515.
View articleSystematic Review and Meta-Analysis of Pathogen Reduction in Onsite Sanitation Systems. (2023).
Examines how environmental, design and operating factors affect pathogen reduction.
View articleJothinathan, H. and Singh, A.P. (2025). Decentralized Faecal Sludge Management in Rural India by Integrating Drying Beds for Dewatering and Coagulation for Leachate Treatment.
View articleCritical Review on On-Site Sanitation Technologies: Typologies, Treatment and Transition towards Circular Economy. (2025).
Reviews treatment options, footprint, capital and operating costs, and future research needs.
View articlePhotographs from the field will be added to this page soon.