Saturday 28 June 2014

The Human Waste Bioreactor

Our idea which was fostered by Gmin's Innovate Kenya was as a result of the  following upcomings;



>The school's newest dormitory was completed and it has a capacity of  720 students . The local community held protests against the completion of the dormitory as the villagers constantly complained about the stench coming from the  sewage  disposal from the dormitories.
> Lack of water currently in the new dormitory sometimes leads to immense blockage  in the  waste disposal system, this waste also overflows to a nearby river which acts as a vital source of water thereby polluting it and consequently its dependants' clean water.


The challenge is important because it motivates us students to think of amicable solutions to the problem. It is a practical problem that is felt and seen by all and therefore needs a practical approach in solving it.The promotion project has the capacity to address energy, health, ecological problems and can be considered as a multi dimensional development approach in Kenya.

Major insipirations  for the production of biogas were political, social , agricultural , environmental , waste recovery and in energy.
-Political: Kyoto Protocol, European Union , National Legislation
Environmental: Reduction of biological and organic wastes
-Agricultural: Waste treatment to obtain fertilizers.
-Waste recovery: Production of new products from waste.
-Social: Boosting the local market
-Energy: Replacement of fossil fuels to local resources.


The human waste bioreactor will be a simple plant dug into the ground with a latrine and a solid waste outlet. This also makes gravity feed of the system much simpler.


After our first camp we were solicited with some funds to come up with a
prototype , we therefore came up with a simple prototype,

Optimistic about our idea, we drafted calculations on how our project would save the school economically wise, picture this:

>In one term, the school uses 28 Lorries of wood fuel each 7 tonnes.
>This is equivalent to 2,940,000 KJ of energy.
 In order to get this amount of  energy;

  1 gramme of methane= 0.055 KJ of energy
  53 tonnes of methane per term= 2,940,00kj of energy
  1 term=14 weeks, therefore
  1 day= 0.54 tonnes of methane

if 1 kg of human waste gives 0.0012m3 0f methane then 540 kg of  methane requires 1,080 kg of waste
If 1,300 students give 200g each of human excreta per day then 260 kgs waste will be produced daily. This is equivalent to 130kgs of gas per day.

If 13 kg of LPG cooking gas costs Ksh. 4,000 daily thus saving the school Ksh.3,920,000 if the school was to use gas from our digestor.

After our second camp, we were able to purchase a digestor  courtesy of Innovate Kenya under Gmins' stewardship.
The digestor was affixed to the school kitchen to a gas stove with a meter reading to monitor gas levels.

Soon after the installation of the digestor we embarked on feeding it, this entailed collecting cowdung from the school farm and  collecting food refuse after meals.


The waste would then be mixed in appropriate ratios with water for optimum production  of the gas.

As soon as there is stable supply of the gas, we hope to avert the dangers that come with using firewood to cook as it remains the source of fuel for the kitchen , clearing our forest cover day by day.



I am glad that the same project was applied in our  rural home ,Taita Taveta, near coast strip, the plant underway will harvest waste from 10 Freshian cows in a zero grazing unit that was initially put to waste, it is my pride that the project will put to perfect use the waste from cows to produce cooking gas for the village, It can also be used in lighting and generating electricity.

The rural home project is underway, the pictures shows its initial phases of construction:

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  1. Congratulations on your success so far, wishing you continued prosperity going forward. You are all a great inspiration and give us hope for Kenya and Africa as a whole. Baraka tele.

    1. Thank you, your encouragments push us even further..

  2. Your consciousness makes you act for a better future.Keep up with the good work bearing in mind that A Healthy Ecology is the Basis for a Healthy Economy.

  3. keep it up and make it even better

  4. Have you considered running a crowd funding campaign? I would be happy to counsel you in the process. Congratulations and keep up the great spirit!

    1. Hi Smith! It will be a pleasure receiving your mentorship in crowd funding campaign, because of so many considerations. Sure reach me on:

  5. I am willing to donate to a crowd funded campaign. It should be possible to make great changes in the lives of many.

    1. Hi Judd!
      We will in due time inform you when it is possible.

  6. With the extra urine, you can probably find a garden that could use some fertilizer. Its great to read about such drive and initiative.

    1. Hi Mat Crichton!
      We are looking on every possible way of conveniently using all Urine -contains nitrogen, phosphorus and potassium -- essential plant nutrients that are usually mined from the earth. Feel free to share any useful information on the same at-

  7. See
    and for similar work!

  8. Hello,

    I'm a reporter for the American online magazine OZY writing an article on using human waste as a biofuel. And I would love to ask you a couple questions about your bio reactor. What's your email adress? I'm at

    With many thanks and best wishes,


    Laura Secorun
    OZY | Writer

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