| At present,the lack of water resources and water environment pollution have become one of the major issues which restrict the sustainable development of social,economic and ecological environment in many countries,and China as the largest country in the world in aquaculture,is facing increasingly serious situation of water pollution.Aquaculture wastewater treatment and reuse has become a key to sustainable development of aquaculture.Artificial wetland is a new sewage purification system that organically combines physical,chemical and biological methods,through a series of physiological and biochemical reactions of plants and microbes,to achieve the sewage nutrient composition and contaminants to be reduced or removed purposes.Artificial wetland system has less investment,quick effect,high removal rate of nitrogen and phosphorus,strong ability to adapt to changes in load and large capacity,etc.recoil concern.In this paper,based on the principle of ecology and system engineering,the design construction pond-artificial wetland water natural circulation purification system.Through reservoir(21.8 acres)-aquaculture ponds(48.5 acres)-artificial wetland(7140 m2)-reservoir((21.8 acres)of water circulation path,complete the aquaculture water purification and recycling.From June 2012 to September 4 times of artificial wetland inlet and outlet water quality monitoring show that the artificial wetland for pond aquaculture water has good purification effect.From the point of the removal of main pollutant,in addition to the chlorophyll a and permanganate index,NH4+-N、NO 2-N、NO-3-N、P043-P,the removal rate of TN and TP pollution indicators range rate of change:73.68%～88.64%,66.67%～77.53%,66.23%～82.76%and 77.53%～66.23%,73.75%～81.67%and 59.18%～81.67%,the average removal rate were 81.80%,72.93%,73.35%,72.93%,77.30%and 64.05%,with the running time goes removal decreased slightly.Artificial wetlands for removal of permanganate index showed the first increase,later decreased,the determination of time change the removal rate of 43.41%～48.00%,the average removal rate was 46.15%,Artificial wetland water quality permanganate index purified water has reached the surface II.water quality standard.At each measurement time,the removal rate of chlorophyll a change in 14.78%～25.00%,the average removal rate was 21.05%,indicating the pond aquaculture wastewater after artificial wetland,the total biomass of phytoplankton has declined,but the decline is small.Wetland Shannon-Wiever diversity index of phytoplankton in produced water between 2～3,no more pollution indicator species in the more dirt belt and a-middle pollution zone,water quality tend to clean.To strengthen the purification effect,in the artificial reservoir constructed set up elastic filler to build biological immobilized microbial membrane.For the water quality of TN,TP,ammonia nitrogen,nitrite,potassium permanganate index of the removal rate of 11.27%～90.00%,to ensure water quality recycled to water.In the application of the pond ecological floating bed system,water TN、NH4+-N、NO2--N and NO3--N removal rate reached 39.4%,51.2%,29.7%and 35.0%,can reduce pollution pond drainage load,easing the impact to artificial wetland substrate,improve the processing efficiency wetland,prolong its life.The circulating water saving system of the pond and artificial wetland built and run,making the external drainage of the pond has been a good purification,can be reused for breeding,water reuse rate is high.The water consumption and drainage amount of the breeding areas are zero,and the annual contribution to the contamination of the original share(COD,TN,TP)is also reduced to zero,achieved good effect of water saving and emissions reduction,has the good ecological benefit and social benefit. |
