潜流湿地及曝气砾石床对污水厂尾水净化工艺包研究

Preliminary study on the purification process package of subsurface flow wetland and ecology gravel bed for tail water

为尾水型人工湿地最佳工艺包的构建提供支撑,选用惰性填料、活性填料、农副产品填料及人工制备填料组成的4类水平潜流湿地模块和目前应用较为广泛的曝气砾石床共计5组平行模块在室外动态条件下净化污水厂尾水,通过调节工况探讨了不同湿地类型及设计工况对水平潜流湿地净化效果的影响.结果表明:基础工况下,曝气砾石床对各类污染物的去除效果较好,生物质填料对各形态氮素去除效果较好.调整工况,尤其是进水增加曝气后,各模块对污染物去除能力显著增强.最优工况下,曝气砾石床在各区设计水力停留时间(HRT)为3,5,3 h时,对TP和COD的去除率分别为87.5%和56.51%;生物质填料模块在HRT为12 h加曝气时对TN去除率为82.37%;沸石填料模块在HRT为12 h加曝气时对NH_(4)^(+)—N去除率为74.58%;改性填料模块在HRT为48 h时对SS的去除率为32.93%,HRT为12 h外加曝气时对BOD去除率为51.44%,以上各指标中TN达地表Ⅳ类水标准,其余指标可达地表Ⅱ类水标准.此外,在一定的污染范围内,潜流湿地模块对高浓度污水有较好的净化作用,出水浓度基本能保证在地表Ⅳ类水以上.

Five groups of parallel modules,including four types of horizontal subsurface flow wetland modules composed of inert fillers,active fillers,agricultural products fillers and artificially prepared fillers,and another ecology gravel beds,were selected to purify the tail water of sewage treatment plants under outdoor dynamic conditions.The working conditions were adjusted to explore the effects of different wetland types and design conditions on the purification effect of horizontal subsurface flow wetlands,in order to provide support for the construction of the best process package for tail water constructed wetlands.The results showed that under the basic conditions,the ecology gravel bed had better removal effect on various pollutants,and the biomass filler had better removal effect on various forms of nitrogen.after increasing aeration,the ability of each module to remove pollutants was significantly enhanced.Under the optimal conditions,the removal rates of TP and COD in the ecology gravel bed is 87.5%and 56.51%respectively when the hydraulic retention time(HRT)was 3,5,3 h.The removal rate of TN in the biomass filler module was 82.37%when HRT was12 h and airing.The removal rate of NH_(4)^(+)—N in zeolite packing module is 74.58%when HRT was 12 h and airing.The removal rate of SS in the modified filler module is 32.93%when HRT was 48 h,and the removal rate of BOD was 51.44%when HRT was 12 h and aeration added.TN reached the surface ClassⅣwater standard,and the remaining indicators can reach the surface ClassⅡwater standard.In addition,within a certain range of pollution,the subsurface flow wetland module has a good purification effect on high concentration sewage,and the effluent concentration can be basically guaranteed above the surface ClassⅣwater.