[February 20, 2012] Valpo sees many benefits in food waste, sludge mix Tweet VALPARAISO, Feb 19, 2012 (The Times - McClatchy-Tribune Information Services via COMTEX) -- Using food waste to generate power at the city's sewage treatment plant could have multiple benefits besides lowering the plant's electric bill. According to information provided by Assistant Utilities Director Steve Poulos, 18 percent of the solid waste now dumped in landfills is food waste. That includes fruits and vegetables and the fats, oil and grease they generate -- a product the city might use to increase the methane generated by the treatment plant. The additional methane would be used to power a turbine to generate electricity that would offset at least some of the $340,000 annual electric bill for the plant. More from the information provided by Poulos: If dumped in a landfill, food waste still generates methane. Methane from landfills is 22 times as harmful to the environment as the carbon dioxide emitted by the treatment plant. When the plant generates its own power, it reduces the greenhouse gases created during the production and distribution of other energy sources. Food waste also is more energy efficient, offering three times the energy potential of the sewage sludge now used to create methane to heat the treatment campus. A ton of food waste generates 13,300 cubic feet of methane, depending on the type of waste. One cubic foot of methane generates 1,000 Bristish thermal unit, and it takes 13,400 Btu to make a kilowatt hour of electricity. Food waste produces more methane and less solids and improves the overall digestion process when mixed with regular sewage. All that reduces the cost of dewatering the biosolids generated, which decreases the cost of disposal of the material. The plant's energy costs are reduced, and the city can collect tipping fees for allowing the food waste to be dumped at the plant. The question of odors will be studied by the consultant as part of the feasibility study, but Poulos said a plant now using the system in West Lafayette has not had complaints about odor and is saving 18 to 20 percent on its electric costs. The city also plans to look for grants to reduce the startup costs for the system. The food waste for the city's plan would probably come from Valparaiso University, restaurants and grocery stores and would not extend to the level of the separation of household waste, Poulos said. ___ (c)2012 The Times (Munster, Ind.) Visit The Times (Munster, Ind.) at www.nwitimes.com Distributed by MCT Information Services [ Back To TMCnet.com's Homepage ]