脉冲SBR工艺短程脱氮的实现及对除磷的强化

Achievement of short-cut denitrification and enhancement of phosphorus removal in a SAOSBR process

采用脉冲进水缺好氧交替工艺(SAOSBR)处理低C/N实际生活污水,考察了短程脱氮对于低碳源生活污水同步脱氮除磷效果的强化作用,并分析了短程脱氮强化生物除磷的机理.结果表明,通过短时的饥饿处理配合缺好氧交替的运行方式实现了系统的短程硝化,亚硝酸盐积累率稳定在95%以上.短程的实现还强化了系统的同步脱氮除磷效果,总氮和磷的平均去除率相比于全程脱氮过程分别提高了约6%和36%.分析表明短程强化生物除磷的原因主要是由于残留的NO2-对聚磷菌厌氧释磷的影响较小.静态试验也证实,在碳源不足的条件下,以NO2-为电子受体的反硝化作用相比于NO3-可以减弱反硝化菌与聚磷菌之间的碳源竞争,从而提高聚磷菌的厌氧释磷量和聚羟基烷酸(PHA)的合成量.因此,在处理低C/N生活污水时,短程脱氮的实现更有利于系统的生物除磷.

The reinforcement of short-cut denitrification towards simultaneous nitrogen and phosphate removal was investigated in a step-feed alternating anoxic-oxic sequencing batch reactor （SAOSBR） treating real domestic wastewater with low C/N ratio. Meanwhile, the mechanism of improving biological phosphorus removal by short-cut denitrification was also analyzed. Nitritation was achieved with the nitrite accumulation rate （NAR） of above 95%, which attribute to starving treatment and alternate with anoxic and aerobic. This nitritation enhanced the simultaneous nitrogen and phosphate removal, and the average removal rate of total nitrogen and phosphate increased by about 6% and 36%, respectively. Batch experiments also indicated that the carbon source competition between denitrifying bacteria with phosphorus accumulating organisms （PAOs） was weaken while nitrite was used as electron acceptor for denitrification under the condition of insufficient carbon source. The reason of enhanced biological phosphorus removal was that residual nitrite had small effect on anaerobic phosphorus release in PAOs. Thereby the quantity of anaerobic phosphorus release and poly-β-hydroxyalkanoate （PHA） synthesis in PAOs were enhanced. Therefore, short-cut denitrification was more advantageous in removing phosphorus in treating wastewater with limited carbon source.