重庆市污水处理厂碳氮磷物质流分析

Material flow analysis of carbon,nitrogen and phosphorus in Chongqing wastewater treatment plant

本文构建了城市污水处理厂物质流分析框架和评价方法,以重庆市A污水处理厂和B污水处理厂A2O工艺为研究对象,通过全流程测试评估工艺脱氮除磷效果,而后利用基于物料平衡的物质流分析方法,分析污水处理系统输入碳(COD)、氮和磷的平衡情况以及物料流向.沿程水质变化表明,两座污水厂COD在沉砂池、厌氧池和二沉池降幅明显,在缺氧池和好氧池中基本没有变化,工艺好氧段硝化效果良好,B厂缺氧段的反硝化效果优于A,两厂生物除磷作用都很弱.物质流分析表明,A厂水量、COD、N和P输入输出的平衡比分别为95.02%、82.13%、87.73%、95.96%,B厂分别为89.9%、91.74%、90.02%、85.46%.B厂存在碳源投加过量的情况,且可能管道泄露;A厂好氧池MBBR系统中可能存在同步硝化反硝化现象,且对自然环境的影响更小.

This study constructed a material flow analysis(MFA)framework and evaluation method for municipal wastewater treatment plant(WWTP).The A2O processes from two WWTPs(named A and B,respectively)in Chongqing were studied to evaluate the nitrogen and phosphorus removal performance.Then,the MFA method based on mass balance was used to analyze the balance of input carbon(COD),nitrogen and phosphorus in the wastewater treatment systems,as well as the material flow direction.The variation in water quality along the process indicates that the COD of the two plants showed a significant decrease in the sand settling tank,anaerobic tank and secondary sedimentation tank,while there was little change in the anoxic tank and aerobic tank.Moreover,the nitrification performance in the aerobic section of both plants were good,while the denitrification performance in the anoxic section of plant B was better than that of plant A.Both WWTPs showed weak biological phosphorus removal performance.The results of MFA indicate that the mass balance ratios of water quantity,COD,nitrogen and phosphorus in plant A were 95.02%,82.13%,87.73%and 95.96%,respectively,while those in plant B were 89.9%,91.74%,90.02%and 85.46%,respectively.There might be the possibility of excessive addition of carbon source and pipeline leakage in plant B.In plant A,there might be simultaneous nitrification and denitrification in the aerobic tank(MBBR),and the impact on the natural environment was smaller.