不同填料对大肠杆菌去除能力的研究

针对丘陵农村地区水质恶化、经济基础差及污水处理能力有限的状况,目前一般采用人工湿地和自然沟渠综合措施处理生活污水,但迄今仍缺乏针对水体病原菌污染的自然生态去除技术研究。为了筛选适宜去除病原菌的人工湿地填料,选用林地土、旱地土、水稻土、生物炭、无烟煤、沸石和石英7种填料,测定不同填料对大肠杆菌的去除能力,并通过在旱地土添加不同比例生物炭(0%、2%、5%、10%、20%、50%),探讨基于大肠杆菌去除容量与去除成本的旱地土与生物炭颗粒物复合物最佳比例。结果表明:不同填料介质生活污水大肠杆菌去除能力由强到弱依次为生物炭>无烟煤>水稻土>旱地土>林地土>沸石>石英;添加生物炭可增大湿地土壤孔隙度,有效提高单位时间内渗滤污水速率,及大肠杆菌的去除率,特别对大肠埃希氏菌去除效果更加明显;生物炭添加可延迟填料到达吸附饱和的时间,有效增加人工湿地处理容量。综合考虑大肠杆菌去除效率和生物炭添加成本等因素,人工湿地生物炭最优添加比例为20%。

REMOVAL CAPACITY OF DIFFERENT ARTIFICIAL WETLAND FILTERS FOR E.COLI

In allusion to the severe deterioration of water quality and the limited economic and technical capacity in hilly rural areas,artificial wetlands and natural ditches are recommended to eliminate contamination of sewage waters.So far,there are few technical researches on removal of pathogens in sewage waters.In order to screen suitable artificial wetland filters for removal of pathogens,seven kinds of biological filters,including paddy soil,forest soil,dryland soil,zeolite,anthracite,biochar and quartz were chosen.Furthermore,based on E.coli removal capacity and running cost,different ratios of biochar addition (0％,2％,5％,10％,20％,50％) into dryland soil were tested for optimal mixing ratio.The results showed that the E.coli removal efficiency of different packing media was as follows:Biochar ＞ anthracite ＞ paddy soil ＞ dryland soil ＞ woodland soil ＞ zeolite ＞ quartz.Adding biochar was beneficial to increase the porosity of wetland soil and improve the permeability of sewage and removal capacity of E.coli.The addition of biochar delayed the time required for reaching maximum adsorption capacity and increased maximum adsorption capacity.Taken into consideration various factors of removal efficiency and cost of biochar addition,the optimum proportion of biochar was at 20％.