循环式活性污泥法工艺运行效果及优化控制方案

介绍了某污水处理厂循环式活性污泥法(CAST)工艺运行情况。生化池由生物选择区及主反应区组成,因此可有效去除COD,出水COD平均为29.5 mg/L,去除率90.7%。提出了以延长回流时间、增强生物选择区污泥混合强度和末端DO含量控制的脱氮除磷优化的控制方案,停止曝气后,增加硝化回流时间0.5~1 h,曝气池末段DO的质量浓度控制在1.5~3.0 mg/L时,系统有较好的TN去除效果,出水TN、NH4^+-N的质量浓度平均分别为10.1、0.805mg/L,去除率分别为69.9%、96.3%。通过改变除磷药剂投加位置和加药系统自动化改造来优化除磷,节省了药剂费用,实际投加量为1.88 t/d,出水TP的质量浓度平均为0.345 mg/L,去除率93.8%。

CAST Process Operation Effect and Optimization Control Plan

The operation status of cyclic activated sludge technology process of a sewage treatment plant was introduced. The biochemical pool consisted of a biological selection zone and a main reaction zone, so COD could be effectively removed, the average effluent COD was 29.5 mg/L and the removal rate was 90.7%. An optimized control scheme for nitrogen and phosphorus removal with extended reflux time, enhanced sludge mixing intensity in biological selection area and the end DO content control was proposed. After stopping the aeration, nitrification reflux time increased for 1~2 h, and the DO mass concentration at the end of the aeration tank was controlled at 0.5~1.0 mg/L. The system had better TN removal effect, the average mass concentration of effluent TN and NH4^+-N was 10.1 mg/L and 0.805 mg/L respectively, and the removal rate was 69.9% and 96.3% respectively. By changing the dosage position of the phosphorus removal agent and the automatic modification of the dosing system to optimize the phosphorus removal, the cost of the medicament was saved. The actual dosage was 1.88 t/d, and the TP mass concentration in effluent was 0.345 mg/L and the removal rate was 93.8%.