污泥浓缩池中磷的释放及其强化去除措施

城市污水处理厂污泥浓缩池上清液和脱水机滤液重新回流入污水处理系统会增加系统的磷负荷。针对污水处理厂剩余污泥浓缩过程中浓缩时间、投加聚合氯化铝(PAC)以及曝气对磷释放的影响进行了研究。结果表明,污泥浓缩池中的剩余污泥静置4h后,释磷速率显著加快。在污泥浓缩池投加0.1g/g干泥的PAC不仅将快速释磷时间延迟至8h,还可以显著降低上清液中的磷酸盐浓度。对污泥浓缩池曝气30min且溶解氧达到3mg/L以上时,上清液中磷酸盐浓度降低了77.7%。通过合理控制剩余污泥在浓缩池中的停留时间、投加PAC以及曝气等,可以降低浓缩池上清液磷浓度,有效提高系统的除磷效果。

Release of Phosphorus in Sludge Thickener and Its Enhanced Removal Measures

The reflux of the supernatant from the sludge thickener and the filtrate from dehydrator will increase the phosphorus load of biological tank in municipal sewage treatment plant. The effects of concentration time, as well as the PAC addition and aeration on phosphorus release in the process of excess sludge concentration were studied. The results showed that the phosphorus release rate of excess sludge in the sludge thickener accelerated significantly after 4 hours. The PAC addition of 0. 1 g/g dry sludge into sludge thickener not only delayed the rapid phosphoixis release time to 8 hours, but also significantly reduced the phosphate concentration in the supernatant. In the case of aeration for sludge thickener for 30 min, making the dissolved oxygen above 3 mg/L, the phosphorus concentration in supernatant decreased by 77. 7%. By reasonably controlling the residence time of excess sludge in the thickener, adding PAC or aeration, the concentration of phosphorus in the supernatant can be reduced , and the phosphorus removal efficiency of the bio-system can be improved effectively.