适宜填料提高温室甲鱼养殖废水曝气生物滤池处理效能

Suitable substrates to improve efficiency of biological aerated filter for greenhouse turtle breeding wastewater treatment

温室甲鱼养殖废水的无序排放已成为长三角农村地区重要污染源之一,特别在温室甲鱼养殖密集区尤为明显。为了探索曝气生物滤池处理温室甲鱼养殖废水的可行性,并筛选适合于温室甲鱼养殖废水水质的生物滤池填料,为处理工艺的实际应用提供参考。该文以斜发沸石、生物陶粒和砾石等3种填料及以此作为填料的曝气生物滤池为研究对象,研究不同填料对温室甲鱼养殖废水N、P的吸附性能及其净化废水的效果。研究结果表明,3种填料的N吸附容量为0.469～0.563mg/g,3种填料对N的吸附量差异不大(P>0.05),P吸附容量0.003～0.114mg/g,其中沸石对P的吸附量最高。在某典型温室甲鱼养殖场建立温室甲鱼养殖废水曝气生物滤池处理中试工程,经过122d的运行,结果表明沸石、砾石和陶粒滤池对COD、NH4+-N、TN(总氮)以及TP(总磷)等污染物均具有良好的去除作用,整个运行过程中COD去除率59.4%～61.1%,NH4+-N去除率达93.2%～97.2%,TN去除率54.4%～71.1%,TP去除率为62.7%～84.3%,沸石滤池对TN去除作用最佳,砾石和陶粒滤池对TP的去除率较好。生物滤池对氮磷的去除是填料吸附和微生物共同作用的结果,填料种类对废水的处理效能影响较小,考虑到填料的成本和来源,砾石是曝气生物滤池处理温室甲鱼养殖废水时较为理想的填料。若在温室甲鱼养殖场位于环境敏感区,对氮的去除要求较高,则可采用沸石为填料。综上所述,曝气生物滤池处理工艺具有较高的推广应用价值,适合中国温室甲鱼养殖场废水的处理。

The greenhouse turtle breeding wastewater contains high concentration of nitrogen and phosphorous. Its unordered discharge has seriously affected the quality and safety of daily and production water supply of the surrounding residents. The greenhouse turtle breeding wastewater has become one of the main pollution sources in the rural area of the Yangtze River Delta, especially in the compact district of turtle aquaculture. In order to provide some experiences for the practical application in a turtle aquaculture farm, the experiment would explore the feasibility of a biological aerated filter （BAF） for greenhouse turtle breeding wastewater treatment, and select a suitable substrate for the BAF. In this paper, we have investigated three types of substrates filling in the BAF, i.e. clinoptilolite, bio-ceramic and gravel, in terms of their capacity of adsorbing the nitrogen and phosphorous in the greenhouse turtle breeding wastewater, and the performance of purifying wastewater. The results have showed that the nitrogen adsorption capacities in the three substrates are similar in the range of 0.469-0.563 mg/g, but that the phosphorous adsorption capacity greatly varies from 0.003 to 0.114 mg/g with the best one from the clinoptilolite. A pilot scale of BAF for greenhouse turtle breeding wastewater treatment was built in one of the typical greenhouse turtle aquaculture farms in the Yangtze River Delta. After 122 days running in the BAF with different influent concentration, the results showed that the BAF with clinoptilolite, bio-ceramic and gravel substrate have good removal efficiency for COD, NH4＋-N, TN, TP and so on. The result of pilot engineering has showed that average COD, NH4＋-N, TN and TP removal efficiencies of a biological aerated filter are 59.4%-61.1%,93.2%-97.2%,54.4%-71.1% and 62.7%-84.3%, respectively. The clinoptilolite filter excels in the removal of total nitrogen （TN） compared to the others, whereas the bio-ceramic and the gravel filters have the better removal capacity of total phosphorous （TP） than the clinoptilolite filter. In addition, the nitrogen and phosphorus removed from greenhouse turtle breeding wastewater by BAF was the combined result of substrate adsorption and microbial functions, which extended the useful life of substrate in BAF. In addition, the types of substrate have little influence on the pollutant removal efficiency of the BAF. Simultaneously, considering the cost and resource of substrate, the gravel substrate would be an ideal substrate of BAF for greenhouse turtle breeding wastewater treatment. However, the clinoptilolite substrate that has a higher nitrogen removal capability would be a suitable substrate for a greenhouse turtle aquaculture farm located in an environmental sensitive area. Therefore, our results suggest the high value of application and dissemination of biological aerated filter treatment in the greenhouse turtle breeding wastewater in China.