暴雨极端天气对污水处理厂脱氮除磷的影响

The Impact of Mechanism of Heavy Rain and Extreme Weather on Sewage Treatment Plant

为研究极端暴雨天气对污水处理厂脱氮除磷的冲击影响,以郑州市某城市污水处理厂为研究对象,考察其2021年夏季3次暴雨前后脱氮除磷表现。结果表明:1)暴雨的冲击对进水水质影响较大,COD均值从400 mg/L降至均值200 mg/L,进水氨氮、TN质量浓度均值分别从25、35 mg/L下降至20 mg/L以下,进水TP质量浓度在暴雨初期有短暂升高2~3 mg/L随后回落。2)暴雨对出水TP的影响最大,有超过一级A标准的风险,对COD、氨氮、TN的出水指标影响较小。3)通过对工艺参数的分析,COD降低导致了好氧池DO和缺氧池ORP的异常升高,条件的变化导致聚磷菌竞争能力弱于反硝化菌,出水TP不稳定是暴雨期水厂运行最主要的风险因素。根据实际情况,控制进水、降低曝气、增加碳源能有效抵御暴雨冲击对脱氮除磷的影响。

In order to study the impact of Extreme Rainstorm Weather on nitrogen and phosphorus removal of sewage treatment plant, taking an urban sewage treatment plant in Zhengzhou as the research object, the performance of nitrogen and phosphorus removal before and after three rainstorms in summer 2021 was investigated.The results show that: 1.The impact of rainstorm has a great impact on the influent water quality. COD decreases from the mean value of 400 mg/L to the mean value of 200 mg/L, Ammonia nitrogen and TN decrease from the mean value of 25 mg/L or 35 mg/L to less than 20 mg/L respectively. The influent of TP increases briefly by 2~3 mg/L at the beginning of rainstorm, and then decreases;2. Rainstorm has the greatest impact on the effluent of TP and the risk of exceeding 1A discharge standard. It has little impact on effluent of COD, Ammonia nitrogen and TN;3. The analysis of process parameters shows the reduction of COD leads to the increase of DO in aerobic tank and ORP in anoxic tank. The change of conditions leads to the weaker competitiveness of phosphorus accumulating bacteria than denitrifying bacteria. The instability of effluent TP is the main risk for the operation of water plant in rainstorm period. controlling influent,reducing aeration and increasing carbon source can effectively resist the impact of Rainstorm on nitrogen and phosphorus removal according to the actual situation.