By LILIAN NAMAGEMBE.
Uganda. – Thanks to the million litres of sewage flushes pumped in the two modern treatment plants of Bugolobi and Lubigi, both Kampala suburbs, farmers have found a goldmine in human waste.
According to the National Water and Sewerage Cooperation (NWSC), a body charged with water supply and sanitation in the country, these two are the only ones which produce the treated fertilisers though there are other 30 treatment plants in different towns across the country.
In his early 30s, January Bagenda, 32, is one of the more than 30 roadside florists at Old Port Bell Road in Industrial Area, Kampala, who have found a treasure in using human waste, also known as bio solid fertiliser.
Bagenda, and his colleagues, stationed a few metres from the Bugolobi treatment plant got the idea to use bio solid fertiliser produced at the plant.
Bugolobi treatment plant is one of the five treatment plants in Kampala where the waste is treated.
Standing mid his flower garden, Bagenda tells the journey to start buying and using human waste as fertiliser for growing his flowers and trees.
Typically regarded as worthless, stinky, and dangerous and packed with poisonous germs, Bagenda instead finds pride in using the solid faecal matter.
“I have used it for the last five years and I can tell you that it is not waste like many take it to be,” Bagenda says.
Bagenda says the most valuable appeal about the bio solid fertiliser is its faster growth of the plant compared to the animal manure.
“Especially in the first two months of using it on the plant,” he notes, “because the human waste fertiliser decomposes at a faster rate compared to animal manure.
The faster the decomposition, the faster the growth of the plant.”
How it works
A moderate solid amount of the bio solid fertiliser is applied on the flower or paspalum because like any other fertilisers, when applied in larger quantities, Bagenda says it causes wilting of the plant.
He, however, says the same method is not used when applying the fertiliser on trees; instead applied two inches on the side row from the plant since the roots are not as near to the plant as those of the flower.
“With this method, the human waste fertiliser becomes more effective in tree planting,” Bagenda says.
The only challenge, Bagenda says, is that; despite the faster growth of plants grown using the human waste fertiliser, it also exhausts faster than the ordinary animal manure due to its faster decomposition.
“The human waste fertiliser only spends between two to three months in the soil which causes the plant to wilt.
The animal manure, however, spends between six months to one year before it gets exhausted from the soil,” he says.
He however, says alternatively, you can keep adding the human waste fertiliser after every two months.
Profiting from the waste
George Kato, 32, a resident of Mbuya, a Kampala suburb was a florist when he explored the idea of trading in human waste.
“Whenever I would use the fertiliser from human waste to design compounds with flowers for my clients, they would like it because it could cause faster growth of the flowers,” Kato says.
“They would keep asking me to get them the fertiliser to even use in their plantations. That is how I started six years back, and made it a business up to now. ”
Kato says although he sells the fertilisers at different prices depending on one’s bargaining power, the prices at which he buys the waste from the treatment plants has doubled over time with the increasing demand.
“It has reduced the amount of profits I used to get from the fertilisers,” Kato says.
At the treatment plant, Kato buys the fertiliser in trucks at Shs40,000 for a small truck which carries three tonnes, and Shs80,000 for a bigger truck which carries eight tonnes and Shs160,000 for a truck that carries 14.5 tonnes.
Although there are not many people who know about this form of fertilisers, there is always negative response from those told about the faecal fertiliser.
“Whenever you tell people that it is human faeces they reject it. But those who have used it appreciate,” he emphasises that it shows results faster.
Kato also notes that the human waste sells more during the rainy season when people are planting.
“I can even sell up to 30 trucks that sometimes it gets finished from the plant when the customers are still yearning for it.”
Expert take
Dr Cranmer Kayuki Kayizzi, a senior Research officer and soil scientist at National Agricultural Research Laboratories (NaRL) in Kawanda, recommends the form of fertilisers to be used in gardens.
He, however, warns that heavy industrial metal contamination can be dangerous to the soil if they accumulate.
“Although we (NaRL) have not done any research on the waste fertiliser, from the scientific point of view, we are sure it can work very well,”Dr Kayizzi says.
Sewage treatment process
Many times when people use flush toilets, few will tell the end point of the sewage flushed out.
The story is not different when pit latrines are emptied and no one imagines the sewage end route can be their farms.
It is however, at this point where the sewage body barges in to treat the solid waste and turn it into odourless blocks that farmers come to collect for use as fertiliser also known as bio solid fertilisers.
By 1pm, under a scorching sun on a Thursday, we are at the Lubigi waste water management plant and sewerage treatment plant, next to Lubigi wetland, in Wakiso District to witness the sewage treatment process.
Eng James Miiro Maiteki, the sewerage services manager at NWSC explains that the Lubigi treatment plant is a unique one for its treatment of both sewerage and septic waste.
The other plants include those in Bugolobi, Naalya, and Ntinda, treatment plants, which are all Kampala suburbs.
At this particular plant, sewage is transported to the plant via the trucks that empty the waste from homes or any other premises. On the other hand, sewerage is transported through pipes.
According to Eng Maitek, the Lubigi treatment plant alone receives up to 2.5 million litres of sewage a day through the pipes. The plant has an inlet pump that allows in sewage to the plant.
“At the preliminary treatment point, solid particles from the sewerage such as the paper, polythene, sanitary accessories and condoms among others are sieved out before they proceed to another channel where sand is removed,”Eng Maitek, explains as we move around the plant.
At the second point, after sieving the sewerage joins the septic sewage which is sorted before its transportation to the plant into sedimentation tank where more solid waste settles.
The liquid is then left to move to another treatment phase.
“Inside the tank, the solid waste (sludge) forms a layer but with more liquid underneath,” Eng Maitek says adding that the waste is then transported to the drying beds where it is dried as fertilisers under an ambient temperature.
The sludge removed in the sedimentation tanks is pumped into sludge digesters where it is digested anaerobically.
“The process here is basically biological and no chemicals are added to disinfect the sewage. More germs and stink are killed when the liquid is separated from the solid waste,” he explains.
After about eight weeks, the purified sludge is pumped into sand drying beds where it is further purified.
Any water that drips from the sludge digesters and sand drying beds is pumped back into sewage treatment.
Eng Maitek says it takes between one to two months for the waste to be dried and get ready for use as fertilisers. They are broken into blocks on drying them.
“The dried sludge at this point is ready to be collected by the farmers for use as manure in crop and flower gardens,” he says it is sold between Shs40,000 and Shs240,000 depending on which quantity one buys.
On a daily basis, one to three tonnes of bio solid fertiliers are produced at the two sewage treatment plants, according to Eng Maitek.
Practice elsewhere
Humans have been repurposing their faeces for thousands of years—some more safely than others. Often known by its euphemistic name “night soil,” the most famous example of raw human waste application might be China, where human excrement was used for centuries in an attempt to close the nutrient cycle in their fields, something that agricultural scientist F.H. King cited in the early 20th century as the reason behind China’s seemingly perennial fertility. While night soil might have helped China’s land retain crucial nutrients, it didn’t win any awards for public health.
Because the night soil was often untreated, pathogens could easily be transferred to both humans and food (so eating raw vegetation was seriously frowned upon).
Biosolids used in the United States aren’t night soil. Regulated by the EPA and federal codes, treatment plants are required to treat the waste at least once before it can be applied to any land. After you flush, your waste is carried along with urine, rainwater and household water to a local sewage treatment plant.
From there, bacteria digest the sludge (the solid waste before treatment, a process that accomplishes two things: it makes the sludge less biologically active (meaning it stinks less) and it reduces the amount of pathogens in the biosolid. Biosolids once treated are called Class B biosolids, and can be used with various restrictions, because while the pathogen levels are reduced by a single treatment, they’re not completely gone. That requires a second treatment—often using high temperatures—and turns the biosolids into Class A biosolids, which have no detectable pathogens and can be used anywhere.
Did you know?
Human urine and faecal matter are a rich source of essential plant nutrients. Historically, human excreta, ‘nightsoils’, were collected from towns and villages and spread in raw or composted form on fields in the surrounding farmland.
This informal treatment is still practiced in some areas of China, South East Asia, Africa and Latin America, where municipal sewage works don’t exist or are poorly functioning. In the 1850s, Europe’s growing urban populations and the discovery of the link between raw sewage and cholera led to the implementation of large-scale sewage systems.
These water-based systems combined all domestic waste, industrial effluent and road surface run-off. For the next century the resulting sewage sludge was disposed of in landfill and directly into the oceans. Eventually, in the 1970s, growing awareness of the environmental impact of sewage on aquatic life led to widespread bans on ocean dumping across the developed world. Since then, research, technology and regulation of wastewater management have progressed to a high standard.
The treatment process starts the moment the sewage is pumped into the separate streams at the plant.
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