August 8, 2006

US ranchers looking for ways to treat pig manure

Pig farmers have always faced a vexing problem: what to do with the hundreds of tonnes of manure each day that are major causes of pollution in the agricultural industry.

Pork producer Gilbert Key in Fayetteville in the US state of North Carolina thinks he has the key to making useful products out of pig manure: earthworms.

Key used worms to break down solid waste in 200-foot troughs. After the worms have done their business, what is left are high-quality compost and cesspools which causes less pollution than raw manure.

Key's capital investment, even with a $750,000 Conservation Innovation Grant, was about US$130,000.

In fact, various technologies have been tried out in the state, where pig farming is big-business. However, many have either been rejected by the industry or earned the ire of the public.

However, Key is trying out the method in combination with other technology, including a separator that removes about 80 percent of the solids flushed from his barns.

While not a perfect technology, researchers in the state continue in their search for the next generation of waste-disposal methods that would be environmentally-friendly and yet come at a low cost.