With all the news these days about renewable energy like solar and wind, even harnessing power from ocean waves, an often-neglected energy source is right under our noses, so to speak: human waste. It may not be as attractive or pleasant as the alternatives, but the generation of energy from human waste could be the most important of all. The world population increases every day along with the demand for energy and resources, and resources become scarcer and more coveted. The only potential resource that will increase proportionally to the population is our own waste. Feces and urine are abundant and readily available wherever there are humans. Today, large amounts of energy from the combustion of fossil fuels and water (often potable) are used to process these waste products. New projects in composting toilets, biogas harvesting, creating biofuels, and even microbial fuel cells could allow us to reverse the cycle and harness this untapped resource.
Although skeptics believe composting toilets will never catch on in the Western world, technologies new and old are being used to solve two problems: how to treat our waste, and how to grow enough food without poisoning ourselves and our environment with chemicals. expensive. fertilizers The next generation of composting toilets, like the one made by Clivus Multrum, is solving these problems and making the system more attractive to consumers. The low-flow composting toilets they produce contain a composting bin in the basement and service is included with the product. The NGO We are in Africa is using a much simpler version of the composting toilet. Although the organization’s goals are to improve sanitation and reduce disease, its programs also help small farmers earn a living. The organization provides composting toilets free of 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 about 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 use the byproduct to fertilize their fields. The biogas produced contains 60-90% methane and is used for lighting, cooking and some engines, and many residents are improving their quality of life and rising above the poverty level. Also, the Cyangugu prison in Rwanda is generating biogas from the excrement of its prisoners. The Kigali Institute of Science and Technology built the digester for the prison, which uses the resulting product to cook 50% of the prisoners’ meals and saves $22,000 a year, a lot 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 for violating federal pollution laws, has piloted a $1.1 million project to collect methane from wastewater from the city and feed it directly into the natural gas distribution system. The project, which is expected to be operational in 2009, foresees a reduction in greenhouse gas emissions of 500 tons per year and enough energy to supply 100 homes. A similar project is underway in San Antonio, Texas.
Current discussions around plant-based biofuels focus on competition between food crops and biofuel crops, with many experts fearing that high demand for biofuels will exacerbate current food shortage problems. Several projects have addressed this problem by creating biofuels from algae grown on human waste. One of them is Aquaflow Bionomic Corporation, which collects the algae used in sewage treatment ponds in Malborough, New Zealand. The “green crude” they create from the algae can be used for all crude oil applications, including gasoline, diesel, and plastics. In a more direct process, a Canadian company called Dynamotive Energy Systems Corporation is feeding human waste directly into a biofuel generation system using a “fast pyrolysis process.” The system achieves 80% efficiency in recovering waste gases and process heat, and the final product, BioOil®, can be used as a substitute for a variety of petroleum products. One of the most advanced and high-tech technologies for creating energy 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 disconnect waste treatment plants from the grid. The fuel cell, which is still being refined to acceptable power output, uses wastewater to generate hydrogen fuel, with clean water produced as a by-product. While the technology is impractical for other fuel cell applications, such as hydrogen-powered cars, it can be used anywhere there is a large amount of biological waste.
Many people cringe at the idea of energy systems based on human waste and would rather not think about what happens in the future, but as humanity becomes more and more energy demanding, we need to start adopting methods unconventional to produce it. With the growing success of the above projects, there is the potential to eliminate human waste pollution around the world. One day, our wastewater will be called “brown gold” and could be even more valuable than crude oil.