CARBONDALE, Ill. -James W. Blackburn, a mechanical engineer from Southern Illinois University Carbondale, thinks he's found a way to turn hog waste into a cheap energy source. And snuff out swine stench. And churn out environmentally friendly fertilizer. All he needs are a few bugs in his system. Not just any bugs, mind you. The kind Blackburn has in mind are aerobic thermophilic bacteria-tiny guys that swing into action when air is added and the heat is cranked up. "In cold weather-say about 13 degrees Fahrenheit-manure from a 5,000-animal finishing operation could produce the energy equivalent of about 67 gallons of fuel oil a day," says Blackburn, an associate professor at SIUC. "Producers could use it to heat the barn, dry feed or run an aquaculture tank." But that's not all, folks. This end product not only will stink less but should be nearly free of viruses and contaminants. It also should contain much more nitrogen than other treated manures, making it a premium fertilizer. What's more, the process would clean up some of the air so the swine barns wouldn't smell so bad. And all this for just about the cost of building traditional waste lagoons. "I've been interested in the use of bioprocesses in environmental areas since the early '80s, but I've yet to be involved with a project that does as many positive things all at once as this one," Blackburn says with enthusiasm. "Usually, environmental projects don't pay for themselves, but in this case, capital investment is likely to be paid back in from one to three years, depending on the farm size, because of heat production and improved fertilizer value." At this point, Blackburn's project, underwritten by a grant from Illinois' Council on Food and Agricultural Research, is just getting off the ground. He has a small treatment unit in his lab on the SIUC campus and is starting to run the tests that will allow him to set up the farm-sized model called for in later stages of his work. "But we know the process works," he says. "What we don't know is how and when this energy is produced during the treatment, how much heat content there is and how much we can actually recover. That's the primary focus for this year." Blackburn estimates that treating waste from a 5,000-animal finishing operation would require a 30,000-gallon, lined and covered pit (about 32 feet across and 6 feet deep), an aeration system and a couple of heat exchangers. Producers would pump manure into the pit where blowers would bubble air into it. As bacteria processed this air, they'd produce heat, bringing the temperature up over 130 degrees Fahrenheit within 12 to 24 hours. Four days later, more than 95 percent of the waste's pollutants would be gone-disposed of by those heat-loving bugs. Residual heat from each treated batch of waste would be enough to heat up the next. Heat exchangers would move excess heat generated from the pit to the pumps that would power the space heaters, feed dryers or aquaculture tanks. "I really don't think the equipment would be any more complicated than farm equipment currently in use," Blackburn says. "Run some pipes, turn some valves, load and empty the reactor-that's within a farmer's ability to operate and manage. "The downside is some farmers will have to put in more time operating this than they currently spend on manure management. They won't have to stand there and watch it-they can walk away and do other things-but it will require some time every week, and farmers will have to spend more time spreading treated manure because the system doesn't have much storage capacity." If the process works as it's supposed to, farmers could adapt it for use in poultry houses, feedlots-wherever large numbers of animals present waste disposal problems. "With new emphasis on environmental practices, animal waste treatment that is energy efficient and cost effective has become a priority," Blackburn says. "This technology can offer an advantage to all livestock producers."
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