On most farms effluent, (that's the nicest label you can possibly put on it), is stored in open lagoons where it sits AND STINKS!! Obviously the stench isn't a big hit with the neighbors, which is a problem, but these lagoons actually present some much more serious environmental hazards. They emit methane and carbon dioxide, both major contributors to climate change. And if they leak or overflow, which they can very easily do during heavy rains, can contaminate the local groundwater. They also regularly end up dumping huge amounts of nitrogen into local streams and rivers and eventually the ocean, causing eutrophication, overgrowth of algae, depletion of dissolved oxygen and dead zones like the one that stretches for hundreds of square miles surrounding the Mississippi delta. It is, for all intents and purposes, toxic waste.
But, by investing in a biogas recovery system, the family-run Homestead Dairy, is turning this waste stream into renewable green energy. If you're thinking: Oh yeah, enough to run a few low-wattage lightbulbs in the barn, you should think again. They're producing enough electricity not just to power their entire farming operation, it's enough to power 1,000 homes! The farm has partnered with the local electric utility which pays the farmers handsomely for their contribution to the power grid. And remarkably, that's just a side benefit.
"It works economically," explains said Floyd Houin, whose family has owned the farm in Plymouth, Indiana since 1945, "but one of the main reasons we did it was to try to help take care of the odor control for the neighbors. ... The land's important to us also," Houin explains further, "because we produce a crop for feeding cows. So we want to do everything we can to take care of the land and the water. We drink the same water as everyone else."
Houin and his family began this process by setting up an anaerobic digester which is a giant shed where animal effluent and other waste is heated,which speeds up decomposition and also allows the farmers to capture both the smell and the greenhouse gases. One of the greenhouse gasses, methane, is used to run the second part of the farm's effluent processing system, the generator. This is how they produce their green electricity.
Houin and his family are not alone in doing this. In fact, according to estimates by The Environmental Protection Agency, Homestead and the 246 other US livestock farms which have installed biogas recovery systems, have eliminated more than three million tons of greenhouse gas emissions last year, the equivalent of taking more than 630,000 cars off the road.
(Source: Phys.org)