Environmental Enhancement of Swine Lagoons through Influent Treatment.

Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. Failure of these lagoons during tropical storms in North Carolina along with major public environmental concerns led to a permanent state moratorium of construction of new anaerobic lagoons for swine production. A NC Department of Agriculture estimate indicates that about 4000 swine anaerobic lagoons are currently active. These lagoons may require cleanup and closure measures in the future. An alternative to lagoon cleanup was investigated by pre-treating the liquid swine manure prior entering the lagoon by solid-liquid separation only and by an ARS patented technology that treats liquid manure by biological nitrification/denitrification after solid separation. In a 15-month pilot study, water quality improvements (such as reduction of suspended solids and nitrogen concentrations) with respect to the anaerobic lagoon control were moderate with just solid separation but very significant with the ARS patented wastewater treatment. In addition, the lagoon sludge mass was reduced with respect the sludge mass in the control by about 34% with solid separation and 50% with the ARS patented technology probably due to the combined reduction in solids input and in-situ lagoon sludge degradation. This finding has the potential to help in the development of more economical lagoon cleanup methods.