Between 8:00pm and 12:00am, on a Friday, 100 patrons repeatedly visited the toilet at Top Notch, a lavish bar in Ntinda, Kampala. Each of them passed out at least 1 litre of urine into the toilet, or five 20-litre jerrycans in total.
There is a way alcohol increases the amount of urine passed by a person.
The urine, however, simply went down the drain as waste. There are hundreds of bars were urine is passed by patrons every day. In Ntinda alone, there are at least 10 other places and if each of these places collects 100 litres of urine, then those are 1,000 litres, just in one locality. This is enough to fend off pests or provide fertiliser for at least one acre.
In a typical household, there are about five people. Each person passes an average of 1 litre of urine per day, if he or she drinks 2 litres of water and this makes at least 10 litres of urine per household.
According to the last National Census, there are about 7 million homesteads in Uganda. If each of these passes 10 litres per day, then that is 7 0million litres of urine passed per day!
Unutilised resource
When improvised bombs started going off in various parts of the country recently. It was discovered that one of the ingredients used to make them is ammonium nitrate, imported into the country as a fertiliser. Therefore, there was a suggestion that the importation of this fertiliser be suspended.
If it is banned, the alternative lies in a natural product, urine. Urine is actually the golden turn that they need to change the fortune on their farms.
“Every day farmers apply commercial fertiliser to their fruits and vegetables to increase yields. But applying commercial fertiliser is expensive and not economically possible for some farmers in countries like Uganda,” says Dr Onesimus Semululu, a senior agriculture researcher with the agriculture ministry.
Composition of urine
Stored human urine had pH values of 8.9 and was composed of eight main ionic species (> 0.1 meq L−1), the cations Na, K, NH4, Ca and the anions, Cl, SO4, PO4 and HCO3. Nitrogen was mainly (> 90%) present as ammoniacal N, with ammonium bicarbonate being the dominant compound. Urea and urate decomposed during storage.
Heavy metal concentrations in urine samples were low compared with other organic fertilizers, but copper, mercury, nickel and zinc were 10–500 times higher in urine than in precipitation and surface waters.
In a pot experiment with15N labelled human urine, higher gaseous losses and lower crop uptake (barley) of urine N than of labelled ammonium nitrate were found. Phosphorus present in urine was utilised at a higher rate than soluble phosphate, showing that urine P is at least as available to crops as soluble P fertilisers.
Comparative expenses on fertilisers
The commonest used fertiliser is NPK. On average, a farmer requires at least 50kg for each acre of land he is using per season. NPK is commonly packed in 50kg bags each costing sh150,000.
Researchers at Kawanda agricultural research institute piloted the use of human urine as an alternative to expensive fertilisers. This resource is very good because it is easily accessible by every farmer, neither does it need to be ‘bought’ from an agriculture store, just like most farm inputs.
“Human urine is rich in nutrients that plants need to grow. Just like the nutrients in chemical fertilisers, those in urine are easily taken up by plants. The well-nourished plant will grow faster, develop more leaves and produce greater yield,” Semalulu says.
When urine is applied to crops instead of fertilisers, farmers save the expenditure on the latter, while achieving the same yield increase. Our findings show that urine can work.
In our studies, we used only urine but also encourage farmers to use some other fertilizers like chicken droppings, cow dung, and compost and also buy if they can afford.
Guidelines when collecting Urine for fertiliser use
According to organic farmer Timothy Njakasi of Kasenge Riverford farm, urine should be collected separately from faecal matter, to allow its use as a liquid fertiliser. In waterless toilet systems the separate collection also reduces odour. Njakasi has got a toilet system that separates urine into a storage area, before it is stored and turned into a fertiliser.
Urine diversion toilets help create manure
The pit-latrines are dug with a provision for a bucket to be placed under the pit-larine, where faeces drop directly down into the bucket within the vault, while urine is diverted into a pipe which is led to a urine storage container for storing wastes and taken to the decomposing site for recycling.
Dry soil with wood ash is added to the bucket after every visit in the faecal matter that helps in dehydrating and also takes away the smell. The feacal matter with ash is transported to the decomposing site for decomposition after which it is used as manure in the garden.
Cover the site with iron sheets to prevent contamination of water whenever it rains and make it more secure for children mainly. The decomposing site is fenced for aeration.
Njakasi explains that this system has revolutionalised his farm.
“We want to build more decomposing sites so that we can use it for manure since we have a large farm not only that but also save water, protect the environment and reconnect nutrient cycles,” he says.
The urine diversion system ensures that the farm has got manure all the time and crops are growing very well.
“We use a wheel barrow to carry the feacal matter with ash from the decomposing site to the farm,” he explains.
To create a decomposing site, one needs at least sh1.5m, depending on the size.
In addition, the farmer needs to buy a drum for storing the faecal matter after decomposition. With this, a farmer can supply the farm on a large scale with manure.
How to construct a urine diversion toilet
After constructing the toilet, use stainless steel fasteners for securing the urine diverter to the barrel and for securing the urine drain cable clamps to the barrel. Holes for fasteners should be drilled using a 3/16-diameter drill bit.
The two holes for mounting the urine diverter to the barrel should be centered on the front of the barrel about 2 and 3 below the lip of the tip. The hole for the urine hose to exit the barrel should be 1/2 in diameter and centered on the front with about 12 below the top of the barrel.
One urine drain hoses from the urinal and one from each barrel will go into the holes drilled near the top of the five-gallon bucket leaching chamber.
Take care to be sure that hoses are level or downhill all the way from urine diversion funnels to leaching chambers. Use soapy water on the end of the hose and on the rubber stopper to help the hose into the stopper.
