亚硝酸盐对聚磷菌厌氧代谢的影响

Effect of Nitrite on Anaerobic Metabolism of Phosphate Accumulating Organisms

以2种强化生物除磷(EBPR)系统中的活性污泥为研究对象,考察亚硝酸盐对聚磷菌厌氧代谢的影响,结果表明:不同EBPR系统中的聚磷菌对于亚硝酸盐的耐受能力不同。人工配水富集聚磷菌的活性污泥,当亚硝态氮浓度超过10mg/L时,聚磷菌吸收VFA受到抑制,PHA的合成减少,磷酸盐的释放增加;处理生活污水的SBR短程脱氮除磷活性污泥,亚硝酸盐的浓度高达30mg/L时,未对聚磷菌的厌氧代谢造成抑制,但引起异养反硝化菌与聚磷菌竞争VFA,导致PHA合成量和释磷量的减少。富集聚磷菌的活性污泥投加亚硝酸盐后P/VFA增大,说明有亚硝酸盐存在时更多的能量用于VFA的吸收。对2种活性污泥中聚磷菌的荧光原位杂交(FISH)定量分析表明:富集聚磷菌系统中聚磷菌含量达到55%,而短程脱氮除磷系统中为7.6%。

Two enhanced biological phosphorus removal（EBPR） sludges were used to investigate the effect of nitrite on anaerobic metabolism of phosphate accumulating organisms（PAOs）.It is found that tolerance of PAOs to nitrite in two sludges were different.In the sludge with enriched PAOs cultures treating synthetic wastewater,when nitrite is above 10 mg/L,it inhibits VFA-uptake of PAOs,leading to decrease of PHA synthesis and increase of phosphate release.In the sludge with nitrogen and phosphorus removal by shortcut nitrification treating real domestic wastewater,anaerobic metabolism of PAOs is not inhibited even when nitrite is 30 mg/L;however,the presence of nitrite in anaerobic period causes denitrifying bacteria compete for limited carbon sources with PAOs,resulting in decrease of PHA synthesis and phosphate release.For the enriched PAOs cultures,the ratio of P/VFA obviously increases when nitrite is added in the reactor,indicating increased energy requirement for PAOs to take up VFA.The quantification results for PAOs in two sludges using fluorescence in-situ hybridization（FISH） show that the PAOs level is 55% in the enriched PAOs cultures,and 7.6% in the sludge with nitrogen and phosphorus removal by shortcut nitrification.