Human waste as an alternative energy source

With all the news about renewable energies like solar and wind power, even harnessing the power of ocean waves, one often neglected source of energy is literally right under our noses: human waste. It might not be as appealing or enjoyable as the alternatives, but generating energy from human waste might be the most important of them all. The world population is growing daily, the demand for energy and resources is increasing, resources are becoming scarcer and more sought after. The only potential resource that will increase in proportion to population is our own waste. Feces and urine are plentiful and readily available wherever there are people. Currently, large amounts of energy from burning fossil fuels and (often potable) water are used to process these waste products. New projects in composting toilets, biogas harvesting, biofuel generation, and even microbial fuel cells could allow us to reverse the cycle and harness this untapped resource.

Although skeptics believe composting toilets will never be successful in the western world, both new and old technologies are being used to solve two problems: how to treat our waste and how to produce enough food without costing us and our environment expensive ones Chemicals poison fertilizers. The next generation of composting toilets, like that from Clivus Multrum, solves these problems and makes the system more attractive to consumers. The low-flow composting toilets they manufacture include a compost bin in the basement, and the service is included with the product. A much more technically simple version of the composting toilet is used by the NGO Estamos in Africa. Although the organization’s goals are to improve sanitation and reduce disease, its programs also help small farmers make a living. The organization provides composting toilets free of charge and has significantly improved the quality of life of many poor families. The organization’s director, Feliciano dos Santos, has just won the 2008 Goldman Environmental Award for ecological sanitation for this work.

Many countries have established methane capture programs that use animal waste, such as B. pig farms in Australia and cattle ranches in the United States. But what about the gassing potential of human waste? Developing countries are pioneering this technology to save money and generate renewable energy. With help from 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 by-product to fertilize their fields. The biogas produced contains 60-90% methane and is used for lighting, cooking and some engines, and many residents improve their quality of life and break the poverty line. Likewise, the Cyangugu prison in Rwanda produces biogas from the excrement of its prisoners. The Kigali Institute of Science and Technology built the cooker for the prison, and the resulting product cooks 50% of prisoners’ meals and saves $22,000 annually – a lot of money in Rwanda. But developing countries are not the only ones benefiting from man-made biogas. The Lions Gate Wastewater Treatment Plant in Vancouver, British Columbia, which was once the subject of a lawsuit for violating state environmental laws, has launched a $1.1 million pilot project to capture methane from the city’s wastewater and feed it directly into the natural gas distribution system to feed. The project, which is expected to be operational in 2009, will reduce greenhouse gas emissions by 500 tons per year and generate enough energy to power 100 homes. A similar project is underway in San Antonio, Texas.

Current debates about plant-based biofuels focus on the competition between food crops and biofuel crops, and many experts fear that high demand for biofuels will exacerbate current food shortage problems. Several projects have addressed this problem by producing biofuels from algae grown on human waste. One of these is Aquaflow Bionomic Corporation, which harvests the algae used in the Malborough, New Zealand lagoons. The “green crude oil” they extract from the algae can be used for all petroleum applications such as gasoline, diesel and plastics. In a more direct method, a Canadian company called Dynamotive Energy Systems Corporation is feeding human waste directly into a biofuel generation system that uses a “fast pyrolysis process.” The system achieves 80% efficiency by recovering off-gases and heat from the process, and the end product BioOil® can be used as a substitute for a wide range of petroleum products. One of the most modern high-tech technologies for generating energy from human waste is the development of microbial fuel cells. Developed by Dr. Bruce Logan of Penn State’s engineering department, the system was proposed to take waste treatment plants offline. The fuel cell, which is still being refined to produce acceptable power output, uses wastewater to produce hydrogen fuel, and clean water is 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 supply of biological waste.

Many people cringe at the thought of energy systems based on human waste and would rather not think about what’s happening in the pipeline, but as humanity increasingly demands energy, we need to start embracing unconventional methods of generating it. With the increasing success of said projects, there is an opportunity to eliminate human waste pollution worldwide. One day our wastewater could be called “brown gold” and even more valuable than crude oil.

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