9/28/2010 SEWER COMMISSION Minutes

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Britain expects to process about 75 percent of their wastewaters (enough to power 350,000 homes), and in Spain, waste could soon supply about 7 percent of electricity demand. Even in the developing world (especially in India, Mexico and South America) villagers and farmers increased their use of simple technologies to convert animal and human wastes to biogas for cooking, heating and farming. Figure 2: Electricity Generate€!from Sewage Per person, kWh, 2007 0 50 100 150 200 250 300 �Ri'iTi3t4� Czech Repubtic Britain Nethpritand5 Finland �l1V�tie1? Beigiicrii Slovakia Suuri:ea Swedish Water&Wastewatt,r As%r iatiui¢ Source:Sweedish Water&Wastewater Association (Taken from The Economist) Several groups are testing ways of making the process of biogas generation much more efficient,many motivated by a desire to find renewable energy alternatives. In Europe, Germany and Great Britain are far ahead in the development of new teclnologies. GENeco, a subsidiary of a British utility company,uses a two-tank,system were different strains of bacteria decompose the wastes,producing about 30 percent more methane than conventional methods. The Fraunhofer Institute in Stuttgart employs a pumped system which mixes the sludge,reducing the amount of time it takes to digest sewage from two weeks to one. This system, already deployed in 20 water treatment plants in Brazil, Germany and Portugal, operates for few hours a day, thus not requiring for its use a large amount of energy. In the United States, two Stanford University scientists are working on an energy-neutral/emissions- free sewage treatment process,bridging two very different fields—space propulsion and environmental biotechnology. The process consists of creating a low-oxygen environment in the treatment plant, and favoring the growth of nitrous oxide-producing bacteria while aerobic species die off. This will increase the production of methane and nitrous oxide to power the sewage treatment plant and small rocket thrusters,respectively. Also, Oregon State University engineers are using nanotechnology to develop electrochemical cells for sewage treatment. By coating graphite anodes with gold nanoparticles, they have been able to extract 20 times more electricity than in previous similar laboratory experiments. Furthermore, according to the researchers the technology could also generate hydrogen gas. A recent joint publication by Duke University and the University of Texas at Austin estimates that exposing wastewater to anaerobic digestion could save 628 to 4,940 million kWh annually in the United States. And the potential gains seem even larger for the developing countries, where sewage often goes untreated and electricity generation capacities are frequently limited.