[permaculture] Solar Ovens to Haiti

Lawrence F. London, Jr. venaurafarm at bellsouth.net
Sat Feb 6 21:02:10 EST 2010

jenny Nazak wrote:
> Lawrence wrote:
> "Remember the earlier post about the site in Africa that collects 
> humanure from an array of johnnyhouses feeding a central collection and 
> digester facility, producing methane for cooking. I have seen the 
> website for this particular project. Its for real"
> Excellent! Now THAT is a truly renewable resource!

If you find the URL to that web page please let me know or post it to 
the list.

Here's more:

Hands On
  Series 6: Programme 4 (of 6) - 'Energy Matters'


Kenyans Throw Out the Flying Toilets
By  Wanzala Bahati Justus
Journalist - Kenya

Read more: 


To remedy the situation, Globology Limited teamed up two years ago with 
the NGO Umande Trust and Ushirika Roho Safi Laini Saba (Swahili for 
cooperating in good faith for the sake of Laini Saba), a community-based 
organization operating in the Laini Saba sector of Kibera. The 
partnership was aimed at finding a solution to the human waste disposal 
problem in Kibera. As a result, a simple, sustainable and innovative 
system for raw sewage treatment called the bio-latrine was introduced.

Through financial assistance from the Swedish International Development 
Agency (SIDA), the Nairobi Central Business District Association 
(NCBDA), and other stakeholders, a bio-latrine was constructed in the 
slum. An estimated US$ 250,000 was spent on constructing the facility.

Many Benefits

“The bio-latrine uses the technology of anaerobic or airless digestion 
to transform human waste into fertilizer and gas suitable for uses like 
cooking, heating and lighting,” said Malcolm Ormiston, a Nairobi-based 
engineer and owner of Globology Limited.

Consequently, the community is able to properly dispose human waste and 
at the same time reduce pollution and environmental degradation.

Ormiston said that the bio-latrine uses standard biogas-system designs 
commonly found in Asian countries such as China, India and Vietnam. But 
the marked difference between biogas digesters and bio-latrines is that 
latrines use human waste instead of animal waste.

The toilet facility and digesters are constructed using conventional 
building materials and require little maintenance.

The systems are scaleable and can thus cater for various sizes of 
populations, ranging from small settlements to large institutions.

“They are ideal for both urban and rural schools and health centers 
where cooking energy is required,” said Ormiston.


Click diagram for a larger view

The bio-latrine consists of three principal components. It is made of a 
conventional pit latrine, the bio-digester and the expansion chambers.

The pit latrine is dry with ventilation pipes to remove odors and trap 
flies. It differs from a standard pit latrine in that the bio-latrine 
unit is shallow and feeds directly into the bio-digester.

The bio-digester is a large underground dome, which during normal use is 
filled to about half its height with the combined urine and fecal sludge.

The bacteria in the sludge break down the pathogens in an airless 
process, producing the methane-based gas.

Ormiston explained that choosing the size of the bio-latrine is based on 
the fact that the sludge must remain in the system for at least 120 
days. This is to ensure that the sewage is well treated and rendered 
harmless by the time it leaves the system.

The gas collects in the space above the sludge and is led out through a 
plug, which seals the top of the dome. Methane is the principal gas 
produced by the latrine. The gas exits the digester through a plug 
inserted into its neck and is then piped through underground pipes 
directly to the appliances in homes or institutions.

The number of appliances that a single latrine can supply depends on the 
number of people using the latrine and the size of the digester. A 
larger number of users and a big of digester will produce more gas. 
Ormiston pointed out that despite the huge potential of this technology, 
it takes five people depositing all of their urine and feces in a 
latrine to produce enough gas for one hour of light or domestic cooking.

According to Globology limited, the most efficient use of the gas is the 
generation of heat for cooking, hot water heating, laundry irons and 
powering refrigerators. The gas can also be burned to create light.

An important way to utilize the gas is in the production of electricity 
from generators built by converted or purpose built internal combustion 
engines. Electricity generation is practical from large-scale 
biogas/latrine systems and calls for greater financial investment and 
effective management. To cash-strapped communities, this is a hindrance 
since sourcing and proper installation and running of generators might 
prove to be a challenge.

The sludge from the bio-digester is fed into one or the various 
interconnected expansion chambers (the number of chambers depends on the 
size of the system), which are also underground, but at a higher level. 
The sludge exits the system mostly from the expansion chambers via a 
pipe leading into the holding tank, where it can be harvested for use as 

The toilet facility and digesters are constructed using conventional 
building materials

Operating and maintaining the bio-latrine is simple given that it has no 
moving parts. The only rule to observe is that apart from human waste, 
the only other allowable material to enter the system is toilet paper.

For the Kibera Laini Saba community, where the bio-latrine is located, 
those who manage the latrine ensure that toilet paper is issued to users 
as they enter the latrine so that they do not use other materials like 
plastic. The usage of the latrine, which was built to accommodate 600 to 
1000 people a day, has been increasing from less than 400 people at 
inception to over 500 a day.

Onesmus Nyamai, chairman of Ushirika Roho Safi Laini Saba community 
group, said that they levy a minimal fee to shower and toilet users to 
enable them to purchase toilet paper and pay the attendant who manages 
the facility."

Read more: 

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