初沉池泥位变化对生物除磷影响规律

Effect Law of Sludge Depths Variation in Primary Sedimentation Tank on Biological Phosphorus Removal

针对城镇污水处理厂进水碳源不足,导致生物除磷效果难以稳定维持的问题,通过实验室小试与现场生产性试验相结合,分析了初沉池不同泥位条件下初沉、剩余混合污泥厌氧发酵产挥发性脂肪酸(VFAs)对生物除磷效果的影响。结果表明,当初沉池泥位由1.0 m增加到2.5 m时,初沉池出水VFAs质量浓度由17.8 mg/L提高到44.0 mg/L。后续改良AAO工艺厌氧段释磷量、好氧段吸磷量较低泥位分别增加了3.26、3.29 mg/L。初沉池2.5 m高泥位条件下,曝气池出水溶解态总磷(STP)质量浓度降为0.06 mg/L,仅为初沉池1.0 m低泥位时的1/2。对磷组分分析发现可溶性活性磷酸盐(SRP)去除率得到明显提升。研究可以为污水处理厂利用内碳源开发提高生物除磷效果提供技术支撑。

The effective biological phosphorus removal is difficult to maintain due to the shortage of influent carbon source in wastewater treatment plant(WWTP).In this study,both the bench-and full-scale testing were conducted to evaluate the production of volatile fatty acids(VFAs)during the anaerobic digestion of primary and surplus sludge in primary sedimentation tank under different sludge depths.The results demonstrated that,with the sludge depth of primary sedimentation tank increased from 1.0 m to 2.5 m,the VFAs contents in its effluent was enhanced from 17.8 mg/L to 44.0 mg/L.Accordingly,phosphorus release and uptake in the anaerobic zone and aerobic zone of AAO process were increased by 3.26 mg/L and 3.29 mg/L,respectively.At a high sludge depth of 2.5 m,the soluble total phosphorus(STP)content in the effluent of the aerobic zone was significantly reduced to 0.06 mg/L,which was only half of that at a low sludge depth of 1.0 m.Phosphorus fractions analysis indicated that the removal rate of soluble reactive phosphorus(SRP)was improved simultaneously.This study provides new insights into the internal carbon sources development for enhanced biological phosphorus removal in conventional WWTP.