Nwasco officials. Photo/the-star.co.ke
Nakuru Water and Sanitation Services Company (Nawasco) has embarked on a project that turns waste into affordable and sustainable energy.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 the 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“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 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.