• The faeces are to be scooped from pits, cleaned of any foreign matter such as paper and sanitary towels then dried before baking into briquettes.
• The briquettes are then produced by compressing biomass residues like charcoal dust, sawdust, other wood remnants or agricultural byproducts into a solid unit that is used as charcoal or firewood.
Image: CHARLENE MALWA
The tiny brick or tin structures with a door or two, often in the corner of homesteads and compounds of public and private facilities, are ubiquitous in rural areas.
The latrines come in handy where indoor plumbing and sewerage services are non-existent.
When full, the solid waste can be manually emptied. Some people pull down the structures and dig up new pit latrines elsewhere when they can no longer be used.
An organisation in Kakamega has stepped in with a project to convert the faeces into briquettes for use as a source of energy.
The Western Water and Sanitation Forum hopes the project will ease pressure on demand for firewood as the primary source of heating in homes.
The faeces are to be scooped from pits, cleaned of any foreign matter such as paper and sanitary towels then dried before baking into briquettes.
The briquettes are then produced by compressing biomass residues like charcoal dust, sawdust, other wood remnants or agricultural byproducts into a solid unit that is used as charcoal or firewood.
If the base materials do not hold together well, a binding substance such as soil, clay or starch is added.
The project is the result of a study in Kakamega in 2019 by WEWASAFO, Masinde Muliro University and Civil Society Urban Development Platform.
They established that 88 per cent of the 2.2 million Kakamega residents use latrines, with only 1.9 per cent using flush toilets and 5.9 per cent ventilated improved pit latrines (VIP). The study was supported by the Embassy of Sweden.
WEWASAFO has been building VIP latrines in public schools in Kakamega county to improve sanitation since 2012. It has built 3,570 VIP toilets under its water, sanitation and hygiene project.
Unsuitable grounds for sinking the pits pose a challenge to the project due to the numerous filled up and abandoned latrines in most schools.
Some schools have had to isolate huge chunks of their compounds as unfit to sustain any development due to poor soil structures.
“We started implementing the Wash project but started encountering challenges because we ended up in abandoned pit latrines which made it difficult to dig proper pits,” WEWASAFO director Humphrey Buradi said.
“We commissioned a study which has come up with findings, including use of the sludge in pit latrines to produce briquettes as a source of environmentally friendly fuel because the briquettes don’t produce smoke,” he said.
Enough quality sludge
The study shows that the faeces in Kakamega county and the Western region can produce briquettes with high heat and that burns longer.
It found that the sludge is not watery because of the heavy consumption of ugali as the staple food makes it higher fibre content.
The study shows that each child in school can produce up to half a kilogram of faeces daily.
The researchers estimated that an average of 700 pupils in each of the 1,620 schools could translate into 567 tonnes of faecal matter daily. This would be adequate to sustain a briquette production plant if established.
The study recommends the use of sludge in toilets for the production of briquettes.
Setting up a medium briquettes plant cost about Sh5 million and requires a minimum of an acre of land. The costing excludes additional equipment such as trucks for scooping and transportation of the sludge, Buradi said.
The study notes there is ease of access to affordable means for collection and transportation of the sludge to be harvested from VIP pit latrines.
“Briquette making is the way to go if we have to conserve forest resources and sustain hygiene in our schools and homes. Land is shrinking and soon or later there will be no space for digging and constriction of new latrines,” Buradi said.
In some schools, there is less than a quarter an acre of land left for any construction. The rest of land that had latrines is unfit for construction, according to the study.
“The social, environmental and economic ramifications of such continued practice is dire and poses a serious threat to the health of the population,” the study found.
Manoah Opanga, a laboratory technician at Masinde Muliro University, said building of VIP toilets with precast concrete lining is another key observation of the study.
“The sludge in our toilets in Western is of high quality for making briquettes but it needs to be secured from mixing with other objects. This calls for the lining of toilet pits to avoid seepage that contaminates underground water and extend the lifespan of the ablution blocks to 180 plus years,” he said.
The study says the practice of digging pit latrines and leaving them when filled up due to the challenges of handling the faecal matter is unsustainable.
Opanga says the non-lined latrines are contaminating underground water posing a serious threat of an outbreak of water-borne diseases. More than 90 per cent of residents rely on water from streams and rivers for their domestic use.
Cost-benefit analysis
Disaster management expert Tom Nehondo said the cost-benefit analysis on what the other uses of human wastes such as biogas technology needs to be carried out. It would help understand what savings the gas gives to people who depend on forests for wood fuel
He said that the cultural beliefs around human waste could pose a serious challenge as it is perceived to be dirty.
“We will need to work on the attitude of the would-be users of the end product to convince them that fuel from human waste whether biogas or briquettes is a valuable source of energy for both domestic and commercial use,” he said.
Efforts to package gas from human waste faced uptake challenges because of cultural beliefs.
Briquettes from human waste may suffer the same consequences unless proper sensitisation is done, Nehondo said.
He said the uptake of the fuel from human waste would be easy in commercial use such as in hotels and schools water heating systems.
“It’s a brilliant idea whose all businesses concepts must be looked at before being rolled out and it can go a long way in conserving our forests and ensuring hygiene,” he said.
Opanga says the companies that will be involved in the production will have to partner with schools in the construction of VIP toilets. It would end the scenarios where schools are closed down due to collapsed toilets on public health grounds.
He said that the value chain must be able to save the environment for sustainability and avoid conflict with the environment.
Nehondo said the technology will come in handy in dealing with the rehabilitation of toilets in schools due to shrinking land sizes. The dregs can be used for fertiliser.
He said that the technology may work well in arid and semi-arid areas because of the drying requirements. Wet conditions in places like Western may pose challenges.