深圳某水质净化厂A/A/O微曝氧化沟深度脱氮除磷工艺效果分析

Effect analysis of deep removal of nitrogen and phosphorus by A/A/O microaeration oxidation ditch process in a municipal wastewater treatment plant in Shenzhen, China

为探究A/A/O微曝氧化沟深度脱氮除磷工艺的性能,根据深圳市某水质净化厂长期监测数据,分析了进水污染物浓度、生物池沿程脱氮除磷性能和微生物相。结果表明:进水可生化性一般,生物脱氮可行,但生物除磷效果有限,需借助化学除磷增强除磷效果,投药浓度与进水BOD5/TP值变化趋势呈负相关;生物池好氧段微生物的氨氧化速率和亚硝酸盐氧化速率能满足硝化反应的正常进行;但缺氧段反硝化速率较低,是生物脱氮的限制因素,可通过降低内回流DO和增加缺氧段碱度来增强微生物的反硝化速率;生物池中有大量的累枝虫、钟虫、盾纤虫和轮虫,且成熟期菌胶团数量较多,结构紧密;深度处理对TP和SS的去除率分别为60.3%和33.71%。物料平衡分析结果显示,被同化的氮含量和反硝化的氮含量各占43%和57%,通过微生物合成和吸附被去除的磷含量和与除磷药剂形成化学沉淀的磷含量各占49.06%和50.94%。本研究结果为水质净化厂深度脱氮除磷提供了思路,可为提高出水水质标准提供参考。

In order to investigate the performance of A/A/O micro-aeration oxidation ditch process on deep nitrogen and phosphorus removal,based on the long-term monitoring data of a municipal wastewater treatment plant in Shenzhen,the concentration of influent pollutants,the performance of nitrogen and phosphorus removal along the A/A/O,and the biological phase were analyzed.The results showed the general biochemical properties for the influent,and feasible biological nitrogen removal effect,while the limited biological phosphorus removal effect.This indicated that the chemical phosphorus removal was needed to enhance the phosphorus removal effect.There are negative correlation between concentration of PAFC dosage and the BOD5/TP of influent.The ammonia oxidation rate and nitrite oxidation rate of the microorganisms in the aerobic section of A/A/O could meet the normal progress of the nitrification reaction.However,the low denitrification rate in the anoxic section of A/A/O was a limiting factor for biological denitrification.The denitrification rate of the microorganism could be enhanced by reducing the internal return DO and increasing alkalinity in this anoxic section.There were a large number of epistylis,vorticellas,aspidiscas and rotifers in the biological pool,and lots of bacterial micelles at the mature stage with compact strucuture.The removal rates of TP and SS by deep treatment process could reach 60.3%and 33.71%,respectively.Through the material balance analysis,the assimilated nitrogen content and denitrified nitrogen content accounted for 43%and 57%,respectively.The percent of phosphorus removed by microbial uptake and adsorption was 49.06%,and the percent of phosphorus formed as chemical precipitate of phosphorus and PAFC was 50.94%.The case provides ideas for deep nitrogen and phosphorus removal in municipal wastewater treatment plant,and provides reference for improving effluent water quality standards.