tailieunhanh - Báo cáo khoa học nông nghiệp " Improvement of water quality of outflows from ponds to waterways "

Ở đồng bằng sông Cửu Long của Việt Nam, chất lượng nước là cực kỳ quan trọng cho con người Y tế và An sinh cũng như các chức năng hệ sinh thái. Nghề nuôi cá tra ở sông Mekong Delta, nào là chủ yếu giới hạn ở các tỉnh An Giang, Cần Thơ, Đốp và Lập Vĩnh Long được coi là có nguồn đáng kể ô nhiễm nước Những tỉnh. Một cuộc khảo sát của 240 Nghề nuôi cá tra ở An Giang và các tỉnh Cần Thơ Cần, và của Cá Catfish Nông dân tỉnh Cần Thơ xác nhận đó xả nước thải. | Technical Report CARD 023 06 VIE Improvement of water quality of outflows from ponds to waterways Cao van Phung1 and Bell 1. Cuu Long Rice Research Institute O Mon Cantho Province Vietnam. Email caovanphung@ 2. School of Environmental Science Murdoch University Murdoch 6150 Australia. Summary In the Mekong Delta of Vietnam water quality is critically important for human health and wellbeing as well as ecosystem function. Catfish farming in the Mekong Delta which is mostly confined to the provinces of An Giang Cantho Dop Lap and Vinh Long is considered to be a significant source of water pollution in those provinces. A survey of 240 catfish farmers in An Giang and Cantho provinces and of Clarias fish farmers in Cantho Province confirmed that discharge of waste water and solid waste from these operations is directly to public water sources in canals and rivers in over 75 of cases. Water consumers in the areas where catfish ponds are prevalent had a strong perception that catfish pond discharge was the major cause of degraded water quality. Water sampling at 2 points of discharge in An Giang over a 5-month period confirmed that discharge causes canal water to exceed discharge standards for COD TSS and NH4. However even background levels were generally above the levels set for household use in Vietnam. Two case studies showed that passing Clarias fishpond waste water or water laden with catfish waste through rice fields improved its quality substantially by decreasing TSS COD BOD N and P. Coupled with evidence that catfish and Clarias fish pond wastes can be an effective partial replacement of rice fertiliser requirements these results indicate that recycling solid waste and waste water from fishponds could be promoted as an effective technology for improving quality of public water ways. The recent decline in density of active catfish ponds in the Mekong Delta during to poor profitability may be having a beneficial effect on water quality. 1 .