MLSS、pH及NO_2^--N对反硝化除磷的影响

Influence of MLSS, pH, and NO_2^--N Concentration on Denitrifying Phosphorus Removal

利用DPB反硝化聚磷污泥以SBR进行试验,以考察MLSS、pH值和NO-2-N浓度对聚磷菌厌氧放磷和缺氧吸磷过程的影响。结果表明:增大MLSS可缩短放磷和缺氧吸磷反应时间,但MLSS过高易导致反硝化吸磷后期出现磷的二次释放;随着pH值的升高(pH=6～8)则P/C值也升高,继续升高pH值到8以上时发生了磷酸盐的沉淀,影响到正常的放磷反应。此外,在反硝化吸磷过程中pH值的大幅升高也会对生物除磷效果造成干扰;控制NO-2-N浓度为5.5～9.5mg/L可使聚磷污泥以NO-2-N作为电子受体进行吸磷反应,当NO-2-N达到15mg/L时反硝化和吸磷反应均受到了抑制。

A series experiments using DPB sludge cultivated in A_2N process were carried out in SBR, in order to study the effect of MLSS, pH, and NO-_2-N concentration on anaerobic phosphorus release and anoxic phosphorus uptake by phosphorus accumulated organism (PAO). The result shows that increase of MLSS can shorten the reaction time of anaerobic phosphorus release and anoxic phosphorus uptake; however, excessive MLSS will result in secondary release of phosphorus at the end of anoxic phosphorus uptake. When pH increases from 6 to 8, P/C increases too, and when pH is higher than 8, phosphate precipitation occurs, which will affect the normal phosphorus release. Besides, great rising of pH during anoxic phosphorus uptake will disturb the biological phosphorus removal effect. When NO-_2-N concentration is controlled at 5.5-9.5 mg/L, NO-_2-N can be used as electron acceptor by DPB for phosphorus uptake; when NO-_2-N reaches 15 mg/L, both the denitrification and phosphorus uptake will be inhibited.