Assessment of Animal Waste Treatment by Means of Biodigesters on Pig Farms in the Red River

The present study was carried out at 12 pig farms in three provinces of Hai Duong, Hung Yen and Bac Ninh. Results showed that the daily amounts of solid and liquid wastes were rather large (50 - 260 kg of solid wastes and 3 - 20 m3 of liquid wastes). The liquid waste treatment with biodigesters decreased the BOD5 and COD concentrations (BOD5 decreased by 75.0 - 80.8% at the sow houses and 75.89 – 80.36% at the growing–finishing pig houses; COD decreased by 66.85% and 64.94 - 69.73% at the sow houses and growing- finishing houses, respectively). However, the COD concentration after treatment was still higher than the hygiene standard. The soluble sulfur concentration was decreased considerably after treatment but was still 3.63 to 7.25 times higher than the hygiene standard. The Cl- concentration was decreased little after biodigester treatment. The Cu2+ and Zn2+ concentrations in the effluent were within the range of hygiene standards.