CEPT/移动床工艺处理低温城镇污水脱氮除磷中试

Pilot Study on Removal of Nitrogen and Phosphorus from Lowtemperature Municipal Wastewater by Combined CEPT and Moving Bed Biofilm Oxidation Process

针对中低浓度城镇污水，在夏秋季中试的基础上研究了化学混凝（即CEPT）／移动床生物氧化工艺在冬春季低温环境下的脱氮除磷效果。试验结果表明，在水温为7～22℃的条件下，组合工艺采用水力停留时间为5～6h、PAC投量为30mg／L、填料投配比为30％、回流比为100％～150％等运行参数，可使出水的NH3-N、TN、TP浓度达到一级B标准；当温度〈10℃时生物硝化和反硝化效率均显著降低；低温下生物除磷以生物合成为主，水温〉14．7℃后生物过量吸磷将成为生物段除磷的核心。

Based on the pilot study in summer and autumn, the removal eglciencies of nitrogen and phosphorus from middle- and low-concentration municipal wastewater by combined chemical enhanced primary treatment （CEPT） and moving bed biofilm oxidation process at low water temperature in winter and spring were investigated. The results show that under the condition of water temperatures of 7 ℃ to 22 ℃, hydrauhc retention time of 5 h to 6 h, PAC dosage of 30 mg/L, filling rate of carrier of 30% and return ratio of mixed liquid of 100% to 150% in the combined process, the effluent concentrations of NH3 - N, TN and TP can meet the class I-B of the national discharge standard. The eglciencies of nitrification and denitrification decrease apparently at the temperature lower than 10 ℃. Under low temperature, biological synthesis takes a main part of biological phosphorus removal; however, when the water temperature is higher than 14.7 ℃, biological phosphorus ultra-uptake by PAOs will play a main role in biological phosphorus removal.