多级A/O工艺强化城市生活污水再生过程的污染物去除效果研究

北京市某城市污水厂在传统的A ²/O工艺基础上特别增设多级A/O(MAO)工艺强化脱氮除磷效果。以该污水厂各工艺单元出水为研究对象,通过对水质常规理化指标、紫外吸收光谱及其相关参数分析,并结合多元数据统计学手段,分析该工艺对城市污水中污染物的去除效果,特别是溶解性有机物(DOM)的去除。经MAO工艺强化后COD_Cr、DOC、TN、TP和N$H^{+}_{4}$-N的去除率分别为95.14%、89.70%、94.53%、97.26%和99.74%,达到GB 18918—2002《城镇污水处理厂污染物排放标准》一级A标准;增设MAO工艺后,提高了对DOM的去除率,DOM分子量和团聚化程度显著提高,化合物的稳定性增强。对污水再生过程处理单元水质化学指标与紫外光谱参数的相关性分析表明,芳香环上取代基类型以脂肪链为主时对脱氮除磷促进作用更加明显。

Analyses on pollutants removal in municipal wastewater reclamation plant with multistage A/O process

A municipal wastewater treatment plant(MWWTP) in Beijing City based on the traditional A 2/O process was added with multi-stage A/O(MAO) to enhance the nitrogen and phosphorus removal effect. The effluent from different units of the MWWTP was studied, and the removal effects of the pollutants in the wastewater especially for dissolved organic matter(DOM) by the enhanced process were analyzed, by analyzing the basic water quality indicators, ultraviolet absorption spectrum and related parameters, and combined with multi-variate statistic analysis. After treatment of the MAO-enhanced process, the average removal rate of chemical oxygen demand, dissolved organic carbon, total nitrogen, total phosphorus, ammonia nitrogen were 95.14%, 89.70%, 94.53%, 97.26%% and 99.74%, respectively, which met first class A of Urban Sewage Treatment Plant Pollutant Discharge Standards(GB 18918-2002). With the addition of multi-stage A/O units, the removal rate of DOM was increased. At the same time, the molecular weight of DOM and the degree of agglomeration increased significantly; the stability of the compounds increased. The correlation analysis of water quality index and ultraviolet fluorescence spectrum shows that the removal of nitrogen and phosphorus is more obvious when the type of substituent is mainly aliphatic chain in the aromatic ring.