The diagram below illustrates the Human waste Biodigester which Express Drainage Solutions Kenya Ltd can design, supply and install;


Why Human Waste biogas Bio-digester?

Express Drainage Solutions Kenya Ltd human waste biogas biodigester can be used in developing nations by families who do not have access to biogas, electricity nor livestock manure. In addition, the household-sized type can be built without industrial construction equipment and access to industrial materials; the use of local materials can be adopted. It would be especially useful in refugee camps where there is no sanitary sewer, people are already exposed to waste-borne illnesses, and there is a high-density living environment without access to electricity; such is the case in many war torn countries in Africa. Try us for you to believe!

What is a bio-gas digester and how does it work?

The picture below illustrates how Express Drainage Solutions Kenya Ltd constructs a human waste bio-digester using cheap local materials;


  • Human waste bio-gas digesters collect waste (feces and urine) and waste from the kitchen in an underground tank.  Microorganisms break down the waste within the tank by digestion, which releases a mix of gases, mostly methane.  The gas rises and collects in a domed ceiling where it builds pressure.  A valve and a hose attached it to the top of the tank, allowing it to be piped directly into the house where it is connected to a gas-burning stove or to other utilities.  The gas does not smell (like many might suspect) and does not make smoke.
  • When the tank reaches capacity, excess effluent that has already undergone digestion (“slurry”) is pushed out of the tank by natural pressure, through an overflow pipe and into a holding bin (displacement tank), where organic waste like leaves, grass or rice husks can be added to create high-quality fertilizer and mulch.

What are the benefits of human waste biodigesters:

  1. Excretement from humans is turned from waste to benefit.
  2. The waste collected from one family provides enough gas for regular cooking needs.
  3. Families with more people hence a larger tank could also use gas for heating and lighting.
  4. The gas is a renewable, clean-burning source of fuel.
  5. Gas replaces wood or charcoal for cooking, eliminating the need to cut firewood and greatly reducing deforestation.
  6. Families in unforested areas no longer have to pay for firewood or charcoal, saving them money.
  7. The post-digestion slurry is (nearly) free of pathogens and creates excellent natural fertilizer and mulch for crops, eliminating the need for families to buy chemical fertilizers, saving them money and retaining more nutrients in the land.
  1. Using gas instead of wood or charcoal eliminates respiratory health issues caused by inhaling smoke from open fires in kitchens and open spaces which affects women especially (who do most of the cooking).
  2. Toilets (or pit latrines) are needed to collect human waste, leading many families to have toilets for the first time. This is important for proper sanitation, which allows many families and children to avoid disease.
  3. Gas provides fuel for boiling water, sterilizing it and saving families and children from waterborne diseases (many people already know to boil water, but where fuel is scarce or expensive, free gas may lead to families feeling freer to boil water more consistently)
  4. If used for lighting, families can avoid using kerosene and its dangers–smoke inhalation and risk of fires and burns




Garden Chambers, 2nd Flr. Off Jeevangee Gardens, Mokhtar daddah Street

+254 727 160738

+254 738 627632

P.O.BOX 8620-00200, Nairobi, Kenya