Turning Urine into Fertiliser
Do you know that instead of flushing urine down our toilets to wastewater treatment facilities, it could be recycled and used as fertiliser?
Yes, pee or even wee as some people say, may offer a solution as a soil amendment. According Business Insider South Africa, researchers say human urine can be used as an alternative to chemical fertilisers with some describing it as the “liquid gold” of wastewater.
In fact, urine can also be used as a renewable energy source. The Africa Energy Outlook 2022, reports that there are still 733 million people in the world who lack access to electricity, including at least 568 million people in Africa. Scientists are finding renewable sources to power the world in more sustainable ways as fossil fuel reserves dwindle and carbon and other greenhouse gas emissions continue to rise. Nigeria has been having electricity supply challenges for many years, making it difficult for households and forcing many businesses to close down due to the cost of fuel to power their generators, according to Voice of America.
The University of the West of England (UWE) with the Bristol Robotics Lab have devised a system that generates power from urine using a microbial fuel cell. The urine is directed from the toilet to the cell, where it is digested by microbes releasing electrons for electricity and a fertliser that boosts crop yields.
The researchers believe the technology could offer a cheap way to power lights for aid agencies in the field. According to Oxfam, “the prototype urinal is the result of a partnership between researchers at UWE Bristol and Oxfam. It is hoped the pee-power technology will light cubicles in refugee camps, which are often dark and dangerous places, particularly for women.”
This system could be used not only in rural settings where power and sanitation infrastructure is often absent but also in the continent’s urban centres where services in densely populated areas such as townships and informal settlements are also lacking. It could also relieve pressure on existing infrastructure that is not able to keep pace with rapid urbanisation as people search for economic opportunities. This also has implications for health systems, according to Nyasa Times poor sanitation accounts for 52% of the disease burden in Malawi.
In 2018, University of Cape Town students used human urine to create the world’s first bio-brick grown from urine. The students collected the pee and first made a solid fertiliser, the leftover liquid was then used in a biological process “to grow” what they call “bio-bricks”. The bricks were produced by Dr. Randall and his students, Suzanne Lambert and Vukheta Mukhari.
But is urine safe to use in our gardens and farms? The short answer is yes. If the urine is taken from a healthy source, it’s clean and contains few bacteria.
Does urine have enough nutrients?
Urine is made up of 95% water and 5% waste products. Human pee is rich in the ingredients commonly used in commercial fertilisers such as potassium, phosphorus, nitrogen, and traces of other nutrients needed for crops and plants to grow. According to Carbon Brief’s Giuliana Viglione, farmers typically apply these nutrients to crops in the form of chemical fertilisers. These fertilisers come at a high environmental cost since they are derived from fossil fuels. Chemical fertilisers when used in large quantities, are harmful to soil and insects and pollute water, according to a report by the Food and Agriculture Organization (FAO).
They also make their way into river systems and other waterways, causing choking blooms of algae that can kill fish and other aquatic life. Researchers say that urine diversion would have huge environmental and public-health benefits if deployed on a large scale around the world. As a result, human pee can be used to save water and contribute to sustainable farming.
A shortage of chemical fertiliser, worsened by the war in Ukraine, is driving up food costs and creating a crisis for poorer countries, reports FAO, and has many farmers desperate and looking for alternatives. Experts writing for The Conversation Africa say the global food supply is now at risk due to the shortage of fertiliser. Many warn that feeding a growing global population in a world of climate change will only become more difficult.
How does urine benefit farmers?
Beside pee from people, animal urine also has many benefits. Kenyan small-scale farmer and entrepreneur Muriithi James Kibuku farms rabbits not just for their meat, and fur but also for their urine. He is the owner of Kibuku Rabbit Farm located in Nakuru, Kenya. He came to gain the knowledge that rabbit urine is good for boosting crops and can be used to repel insects from the farm from a friend and that inspired him to start rabbit farming and “tapping” this resource for his farm.
Kibuku explains that rabbit urine has many advantages as a fertiliser as well as a pesticide. Its pungent smell repels insect pests, making it an organic pesticide. It is environmentally friendly, non-toxic, and cheaply sourced. He explained that urine also neutralises acidity in the soil, and improves its texture, structure, and water-holding capacity. Crops remain green even when the weather is very hot, he says.
In order to collect the rabbit pee, Kibuku designed and built his own cages that collect 90% of the urine. The units direct rabbit waste into gutters that are made of corrugated plastic sheets as rabbit urine quickly rusts and corrodes metal. The urine is then filtered through a screen into a collection bucket, mixed with compost, and allowed to ferment in order to convert it into liquid fertiliser. The solid waste is then harvested and applied directly to the fields as fertiliser, while the urine can be used to create a soil amendment or pesticides.
However, rabbit urine shouldn’t be used directly on your crops since it is highly concentrated, and will burn and kill plants due to the high concentration of nitrogen. Farmers have to first dilute it with water and then apply it to their crops.
Kibuku explains that the demand for rabbit urine is still relatively small but growing gradually as people become aware of the benefits of organic farming. Kibuku collects 30+ liters of pee every day, that he sells for U.S.$0.85 to organic fertiliser companies as well as to local farmers. He previously exported to Botswana before the coronavirus pandemic hit in 2020.
He also sells rabbit droppings to fellow farmers. The rabbit farming industry is gaining traction in Africa and other parts of the world for a number of reasons. Rabbit production is a very lucrative business as it can create multiple streams of income. Fortunately, Kibuku offers training to young farmers that includes modern cage construction, breed selection, diseases, and management. “We also teach skin tanning, and we say nothing goes to waste in rabbit farming,” he adds.
His initiative has helped transform the lives of local farmers and is helping to make agriculture more environmentally friendly. Kibuku Rabbit Farms hopes to sell the rabbit pee to fertiliser companies around the world.
Urine makes for great fertiliser but is it safe?
Helvi Heinonen-Tanski, who has written academic papers on the use of urine as fertiliser, has argued that “urine could have some risk if it contains antibiotics as soil bacteria can become resistant to antibiotics and pass on the resistance to bacteria infecting people”. Heinonen-Tanski points out that urine is practically sterile and poses no health risks when it leaves the body, unlike faeces, which can carry bacteria like salmonella and E.coli.
However, it is advised that farmers should never use urine that is compromised as it is possible for urine to contain medications, hormones, preservatives, and bacteria from urinary tract infections. Experts say urine can be used as a fertiliser without causing antibiotic resistance, although they caution against the use of fresh bodily waste on crops. Antibiotic resistance poses a greater threat to humanity than climate change, according to a report by EuroNews.
“There are certain bacteria that are found in urine that can become pathogenic in your soil environment,” says Portia Phohlo, a sustainable agriculture researcher and expert with extensive experience in the dairy industry. She is skilled in sustainable agriculture, natural resource management, agronomy, pasture and soil management, and soil sampling. Phohlo says if the soil itself has a good bacterial profile, then pathogenic bacteria becomes immaterial because whatever pathogen comes in, it can be countered by the soil organisms that are already there.
“I work for a company where we do give consultations to farmers. And the farmers now that have got very good soil health are really not worried about an increase in fertiliser prices because they’ve got healthy soil that is able to generate its own nitrogen from the soil that already exists. So for those farmers that have got good soil health, biological profile, alternatives, like urine and other things like manure, are not things that are really on the table for them. So from a small-scale farmer’s perspective, if the soil is not good, then it could be a possible amendment but in large commercial farmers, because they usually work towards improving soil health. They wouldn’t use urine as an alternative for fertiliser.
Phohlo added that nitrogen is one of the most important nutrients for the plant. “It’s the primary nutrient. There’s no doubt about that. And what we usually advocate for as a company, we would say, you must ask yourself where are you getting your nitrogen? Is it from the bag, which is like fertilisers, manure, or anything that comes as an input? Or does it come from the soil, because the soil has got thousands if not tons of nitrogen that is there in the soil, but it’s not in an available form. That’s where your microorganisms come in – like the microorganisms that are in your gut, in your stomach – is that as they break down that nitrogen into an available form, like they would break down food in your stomach, and then release that nitrogen to make it available for the plant. “
“Now, the question is, how are farmers trying to manage their soils to get into a place whereby that process by the microorganisms occurs efficiently? That’s the question that farmers need to ask themselves because if you keep on bringing nitrogen into your system, then it starts to become excessive, and then it starts to poison your soil, then you start to have yield issues. So unless you start to wake up the organisms in your soil, you will always be dependent on that external fertiliSer, then you will start to ask such questions. What alternatives can you bring? Like manure and urine, she said.
Phohlo explains the benefits of using urine or manure but advised on how to use it.
“You can apply it only amounts as it is required. And not excessively because the issue is the excessive application of either urine, manure, or whichever form of nitrogen is that if it’s not used by the plant, you know what happens? It gets leached out in your soil, it goes into our water’s groundwater sources, it goes into our fresh water sources, then we have a problem with algae building up in our rivers. And that obviously will affect your aquatic life there.
“And also not to mention that if you apply it in excess, again, it can also get converted into nitrous oxide, which then becomes a greenhouse gas, which obviously will affect climate and climate change. The real issue is not the urine or manure being negative, it’s how much of it you are applying. As long as you apply it as required by the plant, then it’s fine. But if you apply it in soil that’s already saturated with nitrogen and does not need that amount of nitrogen, then it becomes problematic.”
“The advice is simple, farmers need to start moving away from conventional systems like tilling their soils, and plowing, any form of soil disturbance unnecessarily. They need to move away from that and start moving into soil regenerative practices that promote no-tillage of soil and improving root biomass in your soil and planting multi-species of crops or pastures in your system so that you can really build your microorganisms in the soil because what attracts microbes is food and food quality and quality of food must come from the different species of plants that you choose to plant in that system. So that you can start going towards a regenerative health system. Once you have a healthy system, then you will end up finding out that you actually don’t need to apply any form of fertiliser because the soil becomes self-sustaining because it’s rich in microorganisms.”