Economic analyses of pig manure treatment options in Ireland

An economic analysis was performed on treatment options for pig manure in Ireland. Costs were based on a 500sow integrated pig farm producing 10,500m ³ of manure per year at 4.8% dry matter. The anaerobic digestion of pig manure and grass silage (1:1; volatile solids basis) was unviable under the proposed tariffs, with costs at € 5.2m ^-3 manure. Subsequent solid-liquid separation of the digestate would cost an additional € 12.8m ^-3 manure. The treatment of the separated solid fraction by composting and of the liquid fraction by integrated constructed wetlands, would add € 2.8 and € 4.6m ^-3 manure, respectively to the treatment costs. The cost analysis presented showed that the technologies investigated are currently not cost effective in Ireland. Transport and spreading of raw manure, at € 4.9m ^-3 manure (15km maximum distance from farm) is the most cost effective option.