The Ohio State University's Tracy Turner recently published an article in Ag Professional detailing recent measures taken by the state to improve water quality.
Part of the article focuses on Field to Faucet projects, including this excerpt:
"Researchers are studying how best to remove phosphorus and nitrogen from manure and from anaerobic digester discharge before these materials are applied to fields. This effort would especially benefit the watershed around Grand Lake St. Marys in western Ohio, where there are a large number of livestock farms."