Current scenario

  • 1.56 billion liters of untreated sewage flows into River Ganga every day
  • 75% of surface water resources are polluted and 80% is due to sewage alone
  • 61% of rural india and 10% of urban india defecate in the open

Our Work In This Sector

Bio Digesters

Bio Digester is a specially engineered fermentation tank which facilitates the process of anaerobic degradation of human waste converting it into water and methane

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Bio Toilets

Bio toilets is a combination of a Toilet shelter and Bio digester tank. This system can be designed and customized to cater to the exact requirement of the user.

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Comparison chart of Bio Digester and Septic Tank

Sl no


Septic tank

DRDE Bio Digester






Human waste decomposition

Minimal waste decomposition (only 20-40%) resulting in high residual waste.

More than 90% solid waste is decomposed into gases and water.


Air pollution

Foul smelling H2S is emitted.

Emits natural methane and CO2.


Water pollution

As there is minimal waste decomposition, the effluent is polluting.

The remaining effluent is minimally polluting, pathogen free and can be easily discharged.


Pathogen reduction

Aerobic process - most of the diseases bearing pathogens remain active causing water borne disease.

Anaerobic, over 99% disease bearing pathogens are inactivated thus preventing spread of water borne disease.


Space requirement

Higher space for construction as it is designed for larger volume retention.

Requires 50% or less space as the waste gets decomposed and does not require higher retention.


Cost of construction

Larger volume for retention, the cost of septic tank is high.
This also requires soak pit which further add to cost and space.

Smaller volume- lesser cost - between 25% to 50% of a septic tank.


Operation and maintenance

Requires regular evacuation as the undecomposed waste fills up the tank frequently.

Does not require any evacuation or maintenance as the waste gets completely decomposed.



Septic tank does not yield any useful bi-product.

Bio digesters produces high quality balance nutrient rich effluent for horticulture.

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Bio Digester is a specially engineered tank which facilitates the process of anaerobic bio-degradation of human excreta. This process of anaerobic bio-degradation does not require any external energy for its operation which makes this system self-sustainable. The main by-products of this process are methane and water both of which can be recycled.
Our bio digesters are custom- designed and manufactured to meet the exact requirement of our clients.

Salient features of Bio digester:

  • Suitable for ambient as well as sub-zero temperature of Himalayan region, glaciers, plains of north India and coastal regions of south India.
  • In addition to human excreta, it can also be used for kitchen and animal waste disposal.
  • No dependence on the limited and costly conventional energy sources.
  • Easy to transport and install especially in hilly terrains.
  • Little or no maintenance requirement.
  • Significant reduction of pathogens.
  • Generation of odourless and inflammable biogas which can be used for energy generation.
  • Environmentally & economically superior to the existing practice of septic tanks and Leach pits.