With all of the news buzz these days around renewable energies such as solar and wind power, even harnessing the energy of ocean waves, one often neglected energy source is right under our noses, so to speak: human waste. It may not be as appealing or pleasant as the alternatives, but energy generation from human waste could be the most important of all. World population increases every day along with demand for energy and resources, and resources become scarcer and more coveted. The only potential resource that will increase proportionate to population is our own waste. Feces and urine are abundant and readily available wherever there are humans. Currently vast quantities of energy made from fossil fuel combustion and (often potable) water are used to process said waste products. New projects in composting toilets, biogas harvesting, biofuels creation and even microbial fuel cells could allow us to reverse the cycle and take advantage of this untapped resource.
Though skeptics believe that composting toilets will never be successful in the Western world, new technologies as well as old are being used to solve two problems: how to treat our waste, and how to produce enough food without poisoning ourselves and our environment with expensive chemical fertilizers. The next generation of composting toilets, such as that made by Clivus Multrum, are solving these problems and making the system more appealing to consumers. The low-flow composting toilets that they produce contain a basement level compost bin and service is included with the product. A much more low-tech version of the composting toilet is being used by the NGO Estamos in Africa. Although the organization’s aims are to improve sanitation and reduce illness, their programs are also helping small-scale farmers make a living. The organization provides composting toilets at no charge, and has greatly improved the quality of life for many poor families. The organization’s director, Feliciano dos Santos, just won the 2008 Goldman Environmental Prize in Ecological Sanitation for this work.
Many countries have well-established methane-capture programs that use animal waste, such as pig farms in Australia and cattle ranches in the United States. But what of the gas creation potential of human waste? Developing countries are pioneering this technology as a way to save money and create renewable energy. With the help of the Heifer International Foundation, rural farmers in Uganda’s Mukono district are mixing human feces and urine with other biological waste such as water hyacinth and banana peels to create biogas, and using the byproduct to fertilize their fields. The biogas produced contains 60-90% methane, and is being used for lighting, cooking and some engines, and many residents are improving their quality of life and rising above the poverty level. Likewise, Cyangugu prison in Rwanda is creating biogas from the excrement of its prisoners. The Kigali Institute of Science and Technology built the digester for the prison, which is using the resulting product to cook 50% of the prisoner’s meals, and saving $22,000 annually — a great deal of money in Rwanda. But developing countries aren’t the only ones taking advantage of human generated biogas. The Lions Gate Wastewater Treatment Plant in Vancouver, British Columbia, once the subject of a lawsuit regarding a violation of federal pollution laws, has piloted a $1.1 million project to harvest methane from the city’s sewage and feed it directly into the natural gas distribution system. The project, which is expected to be operational in 2009, projects a reduction of greenhouse gas emissions by 500 tonnes annually, and enough energy production to power 100 homes. A similar project is underway in San Antonio, Texas.
Current debates surrounding plant-based biofuels focus on competition between food crops and biofuels crops, and many experts worry that high demand for biofuels will exacerbate current food shortage problems. Several projects have tackled this issue by creating biofuels from algae grown on human waste. One of these is Aquaflow Bionomic Corporation, which harvests the algae used in the sewage treatment ponds in Malborough, New Zealand. The “green crude” they create from the algae can be used for all crude-oil applications such as gasoline, diesel and plastics. In a more direct process, a Canadian company called Dynamotive Energy Systems Corporation is feeding human waste directly into a biofuels generation system using a “fast pyrolysis process”. The system achieves 80% efficiency by recuperating waste gasses and heat from the process, and the end product, BioOil®, can be used as a substitute for a variety of petroleum products. One of the most high-tech, cutting-edge technologies for energy creation from human waste is the development of microbial fuel cells. Developed by Dr. Bruce Logan of Penn State’s engineering department, the system has been suggested as a way to take waste treatment plants off the grid. The fuel cell, still being refined to produce an acceptable energy output, uses wastewater to generate hydrogen fuel, and clean water is produced as a by-product. While the technology is not practical for other fuel-cell applications such as hydrogen-powered cars, it can be used anywhere there is a large supply of biological waste.
Many people cringe at the thought of human waste based energy systems, and would rather not think about what happens down the pipeline, but as humanity becomes increasingly demanding of energy we must begin to embrace unconventional methods of producing it. With the increasing success of the projects mentioned exists the possibility of eliminating human waste pollution worldwide. One day our sewage may be referred to as “brown gold”, and could be more valuable than even crude oil.