Studying on Pig Manure Treatment to Minimize Environmental Pollution and Use Bioenergy

Abstract

This research was carried out on a pig farm in the HUNG YEN Province of Vietnam from October 2008 to August 2009. The farm had 36 sows, selling about 1.5 tons of weaned piglets and 33 tons of live weight pigs per year. The piglets (from weaning to 15 kg) consumed on average 0.42 kg of feed/head/day and produced on average 0.25 kg of solid waste/day. The ratio of solid waste to feed consumed was 0.59. Pigs (from 15 to 30 kg) consumed on average 0.76 kg of feed/head/day, and the ratio of solid waste to feed consumed was 0.61. Growing pigs consumed 1.64 kg of feed/head/day and the ratio of solid waste to feed consumed was 0.49. This ratio for finishing pigs (>60 kg) was 0.46 and consumed feed was 2.3 kg/head/day. For the sows, this ratio was 0.43 for all periods including gestation and lactation. Over 24 hours in winter the biogas produced was on average 4.16 m³/day in the 24m³ biodigestor. This was much less than in summer (9.06 m³/day). To create one kW electricity, 0.92 m³ of biogas was needed. Pig manure treatment by biodigestor has considerably decreased some pollutants, including BOD₅ (Biological Oxygen Demand) concentration down by 77%, the COD (Chemical Oxygen Demand) concentration down by 83%, the dissolved sulphide concentrations down by 88%, the concentration of heavy metals Cu²⁺ down by 52%, Zn²⁺ down by 37%, the Cl^- concentration down by 29% and NH₄-N down by 52%.