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Livestock, Climate Change and the Environment |
A study was carried out to evaluate a method for treating the wastewater from pig pens (consisting of feces, urine and feed leftovers) by draining if to fish and subsequently water-hyacinth ponds and to determine the effect of the number of the pigs per unit of water surface on the water quality parameters: dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solids (SS), total nitrogen, total phosphorus, total Coliforms and parasitic eggs. Samples were taken from six pig houses of the farm at two week intervals.
The results show that the model was effective; the quality of the wastewater in the water hyacinth pond met the government standards and reached type A (Vietnam Standard: TCVN 5945 – 2005). The concentrations of COD, BOD5, SS, total nitrogen and total phosphorus were significantly reduced as compared with samples directly collected from the pens, except for Coliforms. Increasing fishpond water surface area from 105m2 to 227m2/ pig improved water quality parameters. Water quality of the river surrounding the pig farm area nearly reached type A according to Vietnam Standard TCVN 5942 - 1995.
An giang province has an agriculture- based economy. Pig production is considered one of the most important livestock activities in the province, mainly by smallholders. Recently, pig production has rapidly increased to supply the demand for meat. The increased concentration of intensive livestock in associated with the pollution and the pig waste is becoming a serious environmental hazard. Livestock waste causes incessant and pervasive damage to waterways, human health and aquatic life. Water bodies become unusable, while in the remote areas people are still using these for their daily activities. According to a study of Bui Thi Le Minh (2006), more than 25% of householders had no waste treatment method. At the state farms, the common method used to treat wastewater, consisting of faeces, urine and leftover feeds is to directly drain the wasterwater into a closed fishpond or into canals or rivers (Huynh Tan Tien, 2006). A model for the wastewater treatment applied in Vinh Khanh state farm is to direct the wastes from the pig farm to a fishpond, followed by a water-hyacinth pond, which is considered a bio-pond. However, there is a lack of data on the wastewater quality in the treatment ponds and in rivers surrounding the pig farm. The study was undertaken by a team from the faculty of Agriculture and Applied Biology, Cantho University to evaluate a more efficient treatment model and to find out the optimum number of pigs per unit of water surface area to meet the government standard (TCVN 5945 – 2005) by analysing the waste water treatment ponds at Vinh Khanh state farm.
In total there were 931 pigs consisting of sows and boars (but excluding piglets). The pig numbers per unit of fish pond are presented in Table 1.
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Table 1: Number of pigs per unit of water surface area of fish pond* |
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Block |
Pig number (head) |
Surface area in fish pond m2/pig |
| 1 | ||