A/O除磷工艺丝状菌污泥膨胀的研究

丝状菌污泥膨胀是影响活性污泥法高效、稳定运行的重要因素。采用A/O生物除磷工艺中试装置处理实际生活污水,分析了污泥膨胀发生的原因及恢复系统性能的方法。结果显示,长期曝气不均匀是导致丝状菌污泥膨胀的重要原因,通过调控系统运行参数可以有效控制由低DO值或者高负荷引起的丝状菌污泥膨胀。当发生污泥膨胀后,首先降低负荷至0.45 kgCOD/(kgMLSS.d),调节回流比为83%,同时控制好氧池各段的DO分别为1.5、1.0、1.0 mg/L以淘汰丝状菌,在SVI值降至200 mL/g以下后继续降低回流比至53%,同时降低曝气量以形成1.0、0.5、0.5 mg/L的DO浓度梯度。采取上述调控措施后,SVI值由569.8 mL/g降至150 mL/g以下,污泥性状得以恢复;同时出水COD和TP分别在50、0.5 mg/L以下,去除率分别约为85%、95%。

Study on Filamentous Sludge Bulking in A/O Phosphorus Removal Process

Filamentous sludge bulking is an important factor influencing the operation of activated sludge process.A/O process was used to treat domestic sewage,and the reason and recovery of sludge bulking were studied.The results showed that long-term fluctuation of aeration was the key reason of filamentous sludge bulking,and proper regulation of running parameters could effectively control filamentous sludge bulking caused by low DO or high loading rate.When filamentous sludge bulking occurred,the loading rate was reduced to 0.45 kgCOD/(kgMLSS·d),the reflux ratio was adjusted to 83%,and the DO concentrations in different stages of aerobic tank were controlled at 1.5 mg/L,1.0 mg/L and 1.0 mg/L in order to eliminate filamentous bacteria.When the value of SVI was below 200 mL/g,the reflux ratio was decreased to 53% and the aeration rate was reduced to form a DO gradient of 1.0 mg/L,0.5 mg/L and 0.5 mg/L.After these measures were taken,the value of SVI decreased from 569.8 mL/g to below 150 mL/g,and sludge characteristics recovered.The effluent concentrations of COD and TP were below 50 mg/L and 0.5 mg/L,with removal rates 85% and 95%,respectively.