Abstract:

Stable operation of wastewater plants under overload has been a hot spot of concern for researchers，and efficient nitrogen and phosphorus removal is a difficult point in the process of stable operation. A wastewater treatment plant in Zhengzhou uses a pre-anoxic modified A²/O process，treating 1.2-1.8 times the design value，with influent BOD₅/COD，BOD₅/TN and BOD₅/TP ranges of 0.19-0.88，1.38-7.21 and 13.12-89.17 respectively，and uses multi-point distribution of influent，increased internal reflux ratio，precise aeration and other operation methods. The variation of nitrogen and phosphorus in the whole wastewater process was analyzed. The results showed that the removal rates of COD，TN and TP reached 90.4%，83% and 98.55%，which were better than the Class Ⅰ A discharge standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants（GB 18918—2002）， when the influent water was evenly distributed in the pre-anoxic，anaerobic and anoxic sections，the internal return ratio was 400% and the DO concentration in the aerobic tank was below 0.5 mg/L.Some indicators reached Surface Water Quality Standard（GB 3838—2002） Class Ⅲ standard.

Key words: overload, nitrogen and phosphorus removal, wastewater treatment

摘要：

污水厂超负荷下稳定运行一直是研究者关注的热点，高效脱氮除磷是稳定运行过程中的难点。郑州某污水处理厂采用前置预缺氧改良A²/O工艺，处理水量是设计值的1.2~1.8倍，进水BOD₅/COD、BOD₅/TN、BOD₅/TP范围分别为0.19~0.88、1.38~7.21、13.12~89.17，采用多点进水、提高内回流比、精确曝气等运行方式，分析了污水全流程中氮磷的变化。结果表明，当进水均匀分配在预缺氧、厌氧、缺氧工段，内回流比为400%，好氧池DO质量浓度为0.5 mg/L以下时，COD、TN、TP去除率达到90.4%、83%、98.55%，优于《城镇污水处理厂污染物排放标准》（GB 18918—2002）一级A排放标准，部分指标达到《地表水质量标准》（GB 3838—2002）Ⅲ类标准。

关键词: 超负荷, 脱氮除磷, 污水处理

CLC Number: 

• TU992