水力负荷对潜流湿地去除污水处理厂二级出水中氮磷的影响

EFFECT OF HYDRAULIC LOADING RATES ON NITROGEN AND PHOSPHORUS REMOVALS OF SECONDARY EFFLUENT FROM WASTEWATER TREATMENT PLANTS

采用水平-石灰石、水平-沸石、垂直-沸石、垂直-改性沸石等4种潜流湿地对污水处理厂二级出水进行深度处理研究,探讨各系统稳定运行条件下,不同水力负荷对4种潜流湿地脱氮除磷效果的影响,以及4种湿地的去除污染物效果的差异性。结果表明,当进水水质为污水处理厂二级排放标准时,在一定的运行条件下,与垂直潜流湿地相比,水平潜流湿地对氮素的去除效果受水力负荷影响更大。其中,水平-沸石潜流湿地对NH3-N的去除率最高达到(96.5±2.58)%,而水平-石灰石潜流湿地最低仅为(78.7±3.64)%;水平-沸石潜流湿地对TN的去除率最高达到(94.5±2.58)%,最低仅为(66.1±2.02)%。另外,与水平流湿地相比,垂直流湿地对污水中磷素的去除效果较好,同时,垂直-沸石湿地表现出了对磷素最佳的去除效果,其对PO43--P的去除率最高达到(72.1±2.29)%,而对TP的去除率最高最高达到(73.8±3.25)%。此外,当水力负荷为0.093 m3/(m2.d)时,上述4种湿地对磷素均表现出了最佳的去除效果。

Ab^a＇aet： The four constructed wetlands of horizontal-limestone, horizontal-zeolite, vertical-zeolite and vertical-modified zeolite were applied for advanced treatment of secondary effiuent from wastewater treatment plants. Under the conditions of stable operation, the effect ofdifferent hydraulic loading rates for denitrification and dephosphorization of four kinds of subsurface flow constructed wetlands and the difference of four wetlands to remove pollutants effect were investigated. The results showed hydraulic loading rates had a greater impact on horizontal subsurface flow constructed wetland than vertical subsurface to nitrogen removal when water quality for the wastewater treatment plant was discharge standard Ⅱ under certain operating conditions. Among other things, the NH3-Nremoval efficiencyof horizontal-zeoitesubsurfacefl floc nstmctedwe andwasup to （96.5±2.58）% while the horizontal-limestone subsurface flow constructed wetland only was （78.7±3.64）%; the TN removal efficiency of horizontal-zeolite subsurface flow constructed wetland was up to （94.5±2.58）% while the minimum only was （66.1±2.02）%. In addition, compared to subsurface flow constructed wetland, vertical flow wetland exhibited a better removal horizontal characteristic to phosphorus. At the same time, vertical -zeolite wetland exhibited the best phosphorus removal characteristic among the four constructed wetlands, the PO43-P maximum removal rate was （72.1±2.29）% and TP was （73.8±3.25）%. Furthermore, the phosphorus removal of above four wetlands exhibited the best removB1 efficiency when the hydraulic loaditng rate was 0.093 m3/（m2. d）.