Passive Reduction of Methane Emissions from a Hog Waste Lagoon Using a Floating Biofilter System

Roughly 9 million hogs reside in NC in confined animal feeding operations, where waste is stored in anaerobic, open-air lagoons. Methane (CH4) is an important greenhouse gas emitted from lagoons, but there are no regulatory standards. This study evaluates the efficacy of passive biofiltration as a low-cost approach to reducing CH4 emissions from lagoons. Methane emission from a representative lagoon averaged 4.2 g m-2 d-1. Laboratory experiments showed that a community of CH4 oxidizing bacteria initially colonizing a Growstone support medium and subsequently suspended over the lagoon surface was capable of oxidizing 25% of emitted CH4. However,