Nakuru Water and Sanitation Services Company (Nawasco) has embarked on a project that turns waste into affordable and sustainable energy.
The company is making briquettes — a block of compressed charcoal or coal dust used as fuel — from human waste.
Nawasco taps the waste from the sewerage system, which accounts for only 27 per cent of Nakuru’s sludge.
However, this is not the only source of materials. Waste from areas not connected to the sewerage system — totalling between 50 tonnes and 80 tonnes every day — is delivered by exhauster trucks.
“The production of human waste briquettes starts with collection of saw dust from sawmills and faecal sludge from septic tanks and pit latrines from Nakuru Town to the site,” said Nawasco site manager Mr John Irungu.
Once collected, the sludge is dried in the greenhouses, a process that takes place under intense heat to reduce the waste’s water content from around 95 per cent to below 20 per cent.
The next stage is called carbonisation, which involves the sludge being heated further in a drum kiln at 700 degrees celsius.
“This (carbonisation) kills all pathogens and eliminates bad smell emanating from the sludge,” he said. “Most of the impurities contained in the raw material can be very poisonous.”
Separately, the sawdust is carbonised at 300 degrees celsius. The carbonised materials are then crushed into fine powder using a hammer mill.
Using a batch mixer, the crushed materials are blended together in equal proportion.
The next step of making the briquettes involves adding molasses to the mixture which contains lignin that binds materials.
This is done on a rotating drum that turns the mixture into round-shaped briquettes which are then dried in the sun before being used.
Nawasco currently produces two tonnes of briquettes per month.
“The main beneficiaries of these briquettes are households, schools and chicken farmers,” said Ms Reinilde Eppinga, water sanitisation and hygiene (WASH) advisor, one of the partners in the project.
“They are among the largest consumers of energy.”
The project is helping to reduce pollution related to dirty fuels such as petrol and conventional charcoal.
The initiative, she said also leads to lower cases of diseases due to improved sanitation and reduced deforestation.
Nawasco technical superintended Leonard Mutai said the briquettes have been certified by the Kenya Bureau of Standards (Kebs) as well as the National Environment Management Authority (Nema).
WASH says commercial production of the briquettes started in January, after several years of research and development.
The promoters of the project are set to acquire new dewatering and carbonisation equipment which they will use to scale up operations to produce up to 10 tonnes of the fuel per month by the end of this year.
A kilogramme of the briquettes retail at Sh30, meaning that the business could make as much as Sh300,000 per month from the innovative venture, besides ensuring a clean environment.
Once complete, the project will focus on large scale production.
“The briquettes are better than normal firewood and charcoal. They burn for longer and emit less smoke,” said Mr Lawrence Kimaru, a WASH adviser.
He added that the project is a boost to Nakuru County as will generate jobs for the youth.