分段进水多级A/O工艺污泥膨胀的诊断与调控

Diagnosis and Control of Sludge Bulking in Step-feed Multi-stage A/O Process

针对北方某城市污水处理厂分段进水多级A/O工艺出现污泥膨胀现象,结合多级A/O工艺特点分析导致系统发生污泥膨胀的可能原因,通过现场取样观测污泥性状、镜检生物相和衡算沿程各工艺参数等方式,综合分析判断出引起该污水厂污泥膨胀的原因为水温骤降、DO浓度低、MLSS过高、污泥负荷偏低。为降低污泥膨胀对系统运行和出水水质的影响,采取投加药剂、调整曝气量、加大排泥和调整回流比、进水流量分配比等措施,逐步恢复生化系统的稳定性和脱碳脱氮除磷功能。

In view of the sludge bulking phenomenon in the step-feed multi-stage A/O process of a municipal wastewater treatment plant in north China,the possible causes of sludge bulking in the system are analyzed in combination with the characteristics of the multi-stage A/O process.By field sampling,sludge characteristics observing,microscopic examination of biological phase and balance calculation of process parameters along the process,the causes of sludge bulking are found to be sudden drop of water temperature,low DO concentration,high MLSS and low sludge load.In order to reduce the influence of sludge bulking on system disorder and effluent quality,the measures such as adding chemicals,adjusting aeration rate,increasing sludge discharge,adjusting reflux ratio and influent flow distribution ratio were adopted to gradually restore the stability of the biochemical system and the function of carbon,nitrogen and phosphorus removal.