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MEKARN Workshop 2009: Livestock, Climate Change and the Environment |
The research was
carried out on a pig farm in Hung Yen province from October 2008 to August 2009.
The farm had 36 sows, selling about 1.5 tonnes of weaning piglets and 33 tonnes
of live weight pigs per year. For the piglets (from weaning to 15 kg) which
consume about 0.42 kg of feed/ head/day, they produce 0.25 kg of solid waste
(fresh manure excluding urine) in
average per day and the coefficient of the solid waste/feed consumed is 0.59.
Pigs weighted from 15 to 30 kg consuming about 0.76 kg of feed/head/day, and the
coefficient of the solid waste/feed consumed is 0.61. Growing pigs consumed 1.64
kg of feed per day and the coefficient of solid waste/feed is 0.49. This
coefficient in finishing pigs (>60 kg) is 0.46 and the feed consumed is 2.3 kg.
For the sows, this coefficient is 0.43 for all different periods (gestation and
lactation). After 24 hours, in winter, about 4.16 m3 of biogas will
be produced a day in the biodigestor of 24m3, it is much less than in
summer (9.06 m3/day). To create one KWh of electricity, 0.92 m3
of biogas is required. Treatment of pig manure by biodigestor has decreased
considerably some polluting components such as BOD5 concentrations
decreased 4.37 times, the COD concentration reduced 5.9 times, the dissolved
sulphide concentrations reduced 8.44 times. The concentration of heavy metals Cu2+
decreased 2.09 times, Zn+ reduced 1.59 times, the Cl-
concentration reduced 1.41 times, NH4-N reduced 2.07 times.
Key words:
solid waste, liquid waste, biogas