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  • Aasavari Joshi

Recycling Human Faeces Could Unlock a $9.5 Billion Opportunity

We press the toilet flush without an afterthought and think of human faeces as a waste product. However, this mindset disregards the fact that organic waste can and must be recycled back into ecosystems in a time of climate change and increased environmental consideration. Toilets that safely contain and treat human excrement are uncommon despite their effectiveness, since most cultures find them reprehensible. Current toilet systems use a great amount of water to flush faeces into energy-intensive, overburdened sewage networks and facilities.

New inventions and technologies are at the heart of many solutions to environmental issues. But what if we tried to change human behaviours that are at the origin of such issues? What if the root of many problems lies in internalised taboos, prejudices, and cultural practices? Our conception of what constitutes waste and what represents value must evolve as we search for more environmentally friendly ways to live and lessen our negative impact on the environment.

With the help of domestic biogas technology, toilets can be connected to anaerobic digesters. These are airless machines where bacteria convert organic waste into clean, sustainable biogas. Although such toilets are currently more prevalent in low- and middle-income countries, this technology has the potential to be implemented more widely on a global scale. Turning human waste from a disposal concern into an energy source may be a simple—and profitable—solution, according to a study by United Nations University - Institute for Water, Environment and Health. Water content in human faeces ranges from 55% to 75%. The remaining 25% to 45% is made up of solid residue and gaseous methane, which is created by bacterial decomposition and has an energy value comparable to that of coal. Unlike coal, this source of fuel doesn't require much searching or mining and can be of equally great value.

According to a U.N. assessment, the value of human waste being used as fuel might be as high as $9.5 billion worldwide. The human waste generated by the billion people who lack access to proper sanitation facilities alone may generate enough methane to power 10 to 18 million houses and represent a financial value of up to $376 million. The energy gained from such compact, solid waste can make up to 8.5 million tons of charcoal for use in industry. The ineffective handling of human waste "has few peers when it comes to inflicting misery and poverty," said Zafar Adeel, the director of the U.N. body. "If we can demonstrate a fresh, straightforward strategy, we can promote development, safeguard the environment, and aid in the reduction of sanitation issues, which account for one-tenth of all global illnesses”.

Up to now, only solid waste has been considered in this energy-generating equation, but the annual amount of generated urine also plays a part. A Swedish study found that every 1,000 litres of urine include 900 g of sulfur and 600 g of phosphorus and potassium. According to the World Health Organization, a single human being generates 4.5 kgs of nitrogen annually when combining liquid and solid waste. All of this may be recycled into plant nutrients, boosting food yields and, thus, assisting in the reduction of hunger and poverty.

These concepts for recycling excrements go far beyond the idea of composting faeces in a remote rainforest ranch. There is a growing movement to utilize our bodies' metabolic waste in locations ranging from farms and off-the-grid communities to small eco-villages and all the way up to large cities. There are several reasons to do so. The nutrients in our faeces make it a strong fertilizer that can stimulate plant growth. In the current age of climate change and water scarcity, composting instead of flushing down human waste also reduces water usage. Additionally, applying it to soil in crops minimizes the need for synthetic fertilizers, which are produced using fossil fuels and wash away from fields into rivers and lakes, consequently polluting these.

A pilot project is being started in Uganda, Africa, with funding from the U.N., the Ugandan Ministry of Water and Environment, and Canada. The project will incorporate both centralized and decentralized collection of human faeces in institutional settings, such as schools and jails as well as places with low or no sanitation. Similar smaller-scale research projects are being conducted in other African countries such as Kenya. Authorities in Singapore, in turn, where it has become a common practice to drink water gained from recycled sewage, have supported positive media campaigns explaining the science and environmental benefits of treating human waste. More crucially, they have helped to normalise the drinking of recycled water. The influence of social norms and the potential for positive information dissemination by the media should be recognized by policymakers when seeking to implement such new practices.

Faeces recycling may seem reprehensible and dirty, but it is being increasingly seen as a crucial element in the circular economy approach, which involves processing different forms of waste into valuable materials or products. According to Kelsey McWilliams, founder and managing director of Point of Shift, a Philadelphia-based firm that creates circular sanitation systems, "this topic is super-hot right now." People are becoming increasingly interested in circular sanitation, especially in the US but also in other countries, as they realize that many of our daily practices are not sustainable in the long-term. It will evidently take time to scale current small pilot projects up to a potential global faeces recycling system. Nonetheless, an effective circular sanitation system would offer a long-lasting and environmentally friendly solution to the handling of human waste on a global scale.


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