侧流污泥返送到缺氧池对A^2/O系统效能影响研究

Effect of side-stream sludge returning to anoxic tank on A^2/O system effectiveness

为了探究侧流化学磷回收后生物污泥返送对主流系统的影响,连续85d对A^2/O系统厌氧池混合液中的磷进行侧流化学回收,并将侧流生物污泥回流到缺氧池,考察了系统整体的磷、氮、有机物的去除,及生物除磷途径与污泥性能的变化.结果表明,刚开始系统除磷效果有所提高,出水PO_4^(3-)浓度为(0.07±0.04)mg/L;20d后污泥沉降性能开始变差,除磷性能恶化,但对氮和有机物去除一直无显著影响;厌氧释磷速率和好氧吸磷速率下降,但缺氧吸磷速率却增加,缺氧反硝化聚磷和好氧聚磷的除磷比例由43.20%上升为53.38%,反硝化聚磷除磷得到了加强;污泥微生物胞内PHA和糖原的代谢模式无变化,但厌氧段合成的PHA量逐步下降;侧流磷最大回收量占进水磷量的24.75%,能够实现可观的磷回收效果;系统发生崩溃后,停止侧流化学磷回收,系统各功能就会逐渐得到恢复,可实现系统连续运行.

In order to explore the influence of biological sludge return on performance of the mainstream system after chemical phosphate precipitation in the side-stream,phosphorus,nitrogen and organic matter removal,pathway of biological phosphorus removal and sludge sedimentation of the whole system after 85days of side-stream chemical phosphorus recovery with the sludge returned to anoxic tank in the A2/O system were investigated.The results showed that the phosphorus removal of the system could be improved at the beginning of the operation,the concentration of soluble phosphate in effluent was(0.07±0.04)mg/L;After 20 days’operation,the sludge settling performance became worse,and the phosphorus removal performance deteriorated,but the nitrogen and the organic matter removal performance were not significantly affected.The rate of anaerobic phosphorus release and aerobic phosphorus uptake decreased,but the rate of anoxic phosphorus uptake increased.The phosphorus removal ratio of anoxic denitrifying phosphate accumulation to aerobic phosphate accumulation increased from 43.20%to 53.38%,so the denitrifying phosphorus removal was strengthened.The metabolic patterns of PHA and glycogen of microorganism in the sludge were not changed,but the amount of PHA synthesized in anaerobic stage decreased gradually.The maximum recovery amount of phosphorus by side-stream accounted for 24.75%of that in the influent,which achieved considerable phosphorus recovery.When the system collapsed,the side-stream chemical phosphorus recovery was stopped for a short period,the functions of the system were gradually restored,and the continuous operation of the system could be realized in result.