According to statistics of Vietnam Association of Seafood Exporters and Producers (VASEP), waste from catfish ponds released to the environment in 2006 and 2007 was approximately 3 and 4 million tons. These substances are excess food, rotting decomposition, residues in the process of using chemicals, antibiotics, fish waste in ponds ... constitute the toxins in the water environment. The early finding of a wastewater treatment technology for catfish ponds is a matter that should be placed at the forefront of the solutions to develop sustainable pangasius farming.
In order to find out the method of wastewater treatment in aquaculture in accordance with the farming conditions in An Giang, contributing to limiting environmental pollution and spreading diseases, in March 2008, the Center for Breeding and Breeding In cooperation with Hoai Nam - Hoai Bac Manufacturing - Trading - Service Co., Ltd (Ho Chi Minh City), an experimental model of wastewater treatment in catfish pond was established. High speed Purolite at Binh Thanh Aquaculture Farm, Chau Thanh district. This is the method of polymerization, the suspended substances or dissolved in water after being treated with chemicals will settle to the bottom and will be eliminated, the internal water will be re-used. again. Recycled water meets category A-TCVN 5945: 2005. With this model, wastewater in nursing ponds is recirculated to ponds throughout the nursery.
Compared to the currently recommended wastewater treatment methods such as continuous and batch treatment, treatment with mussel and mouse ear, treatment with SEMSR, treatment with EM In combination with PAC, high speed Purolite treatment has the advantage that only small area (5% of nursing pond area) and non-prolonged treatment time do not discharge to the environment.
The trial was conducted as following: 2 ponds were selected (1 control pond and 1 experimental pond) with an area of about 2,000m2 / pond, 1.5m deep. The trial period was equal to that of a nursing spawning period of 2 months. Periodically, each water change will be treated for wastewater. Pre-treatment and post-treatment water samples will be collected for comparison of environmental factors (BOD5, COD, DO, NH3, pH, H2S, SS, Coliform), compared with standard VN 5945: 2005 and TCVN 6774: 20 (standard for freshwater quality to protect aquatic life).
