Yes, you read that right. In a recently published paper, researchers turned human waste into a carbon-rich material, which they found produced enough energy when burned to be considered a potential energy source in the future.
Human waste is typically thought of as unsanitary and harmful, as it has the potential to carry pathogens and transmit diseases. However, it is also composed of high levels of carbon, so after being processed, it can actually be turned into a carbon-rich coal-like material called hydrochar. This method of processing is called hydrothermal carbonization (HTC), and does not generate any hazardous by-products. It heats the wet biomass, dries it by removing most of the water content, and sterilizes the product by degrading most of the micro-pollutants.
The produced hydrochar can be turned into pellets (as pictured) and used as a biomass fuel. (Photo Source: © Kapilbutani and made available under a Creative Commons Attribution-Share Alike 3.0 Unported license.)
Human waste is typically treated either chemically or biologically. However, many developing countries have difficulty accessing these treatments, making it difficult to handle and sanitize large amounts of human excreta.
One way of reducing it is using it as a soil fertilizer. Human excreta, specifically feces, have actually long been used as a fertilizer, as it contains key plant nutrients such as nitrogen, phosphorus, and potassium. Humans have repurposed poop before, so why not use it as an energy source? The study found that the amount of energy released as heat from the combustion of hydrochar was high enough to potentially be used as an energy source. If this method is perfected, it would be tackling two problems at the same time – waste and energy.
A man pouring fertilizer onto a field to dry. (Photo Source: © Ahmad Masood / Reuters)
With our climate rapidly changing, it is important to develop new methods of gathering usable forms of energy that are both renewable and sustainable. In my opinion, using human excreta as a potential biomass fuel is very smart, as it is cheap, readily available, can help treat and reduce the amount of human waste in developing countries, and can possibly be used as a sustainable and renewable form of energy in the future.
– Kristy Ip
