Research On Aquaculture Water Quality Improvement In Ecological Agriculture District

With the rapid development of the aquaculture industry, aquaculture wastewater with the characteristic of large amount of drainage and higher pollution has caused serious pollution to the environment and became an urgent problem. This paper relies on the "Ecological agriculture research and demonstration of ecological restoration technology integration of water environment" (Shanghai science and technology commission of major research about special topics.08dz1900407), to do research on the drainage purification of aquaculture in Songjiang agricultural district. According to the characteristics of agricultural area, based on ecological principles, use floating beds of aquatic crops, aquatic plants, aquatic animals and ecological revetment stocking integration technology, to improve water quality of drainage, in the same time, enhance the economic benefits of eco-park, for providing the technical foundation about improving the aquaculture water quality and economic benefits of ecological agricultural park. The main conclusions are as follows:(1) The results that to investigate the aquaculture wastewater's background value of Wushe agricultural district showed that:the sewage strength was higher than the average level of Shanghai general aquaculture. TN, NH4--N, TP, CODCr average content reach to 3.2mg/L,0.70 mg/L,0.44 mg/L,73.3 mg/L.(2) Use floating beds of aquatic crops, aquatic plants and aquatic animals, ecological revetment stocking integrated demonstration projects, to improve water quality of aquaculture drainage. Spinach, water celery and other crops grown in the river, as well as water hyacinth, on the one hand to purify wastewater and increase the economic benefits of the park; Use eco-concrete technology with biological materials to soften some hard bank of the park, to restore riparian vegetation, to provide good habitats for biological and have certain economic benefits, reflecting the ecological model of the agricultural district. Effect on operation of demonstration projects were investigated, and results show that:choose the integration technology on the drainage channels and water quality conditions improved. TN, NH4-N, NO3--N and NO2--N of the river removal rate of 30%,25%,20%,70%; TP removal rate reached 54%, CODCr removal rate of 60%. (3) Studied the absorption capacity of aquatic plants and the transfer rules in various organs for nitrogen and phosphorus, the results show that:Nitrogen and phosphorus accumulation in various organs of leaf>root>stem, N and P contents of leaf reached 51g/kg,36g/kg. With plant growth the nutrients gradually transferred to the roots for the winter, the roots contain nitrogen and phosphorus content that will gradually increase, reaching 36 g/kg,16 g/kg. Within one year, spinach on N, P removal amounted to 122 kg,14 kg, water hyacinth on N, P removal capacity of 37 kg,4.6 kg. Bacteria in water and microorganisms of plant roots were studied and the results show that the number of microorganisms in water will increase with the growth of plants.(4) On the economic benefits of aquatic crops were analyzed, the results showed that:With the demonstration project running one year, reap the water spinach for 8 times, about a total of 11900kg, the average per harvest was 1488kg, to achieve economic gains 48,000 Yuan. Compared with terrestrial plant, the ratio is higher of output to input.In short, the application of integration technology can reduce the water pollution of drainage and improve water environment, produce economic benefits. This reflects the ecological agriculture pattern, had a good role model and the reference value, and provides technical basis and guidance about the water quality improvement of aquaculture drainage.