(AO)2-SBBR反硝化除磷工艺处理低碳城市污水

低碳源浓度城市污水的脱氮除磷一直是个难题，为此在AO-SBBR工艺中引入一个缺氧段而形成（AO）2-SBBR工艺，研究了AO-SBBR和（AO）2-SBBR对低碳源浓度城市污水中氮、磷的去除效果。试验结果表明：在进水BOD5／TN=3、BOD5／TP=17的情况下，（AO）2-SB．BR工艺比AO-SBBR工艺具有更好的同步脱氮除磷效果，对总磷的去除率达到了79．8％，对总氮的去除率从25．83％提高到51．26％，出水水质达到了《城镇污水处理厂污染物排放标准》的一级标准。该工艺有效解决了低碳源浓度城市污水在同步脱氮除磷过程中有机物不足的问题，并在单一反应器中实现了反硝化除磷菌的增殖过程，反硝化除磷菌占聚磷菌的比例从14．82％增长到63．04％；反硝化除磷菌能够以低浓度的亚硝酸盐氮作为电子受体进行缺氧吸磷，如亚硝酸盐氮〉10mg／L则会抑制反硝化除磷菌的活性，而且这种抑制作用并不是瞬时的，至少要持续一段时间其活性才能恢复。

Low Carbon Source Urban Wastewater Treatment Using (AO)2-SBBR Denitrifying Phosphorus Removal Process

Low carbon content has always been a difficult problem for nitrogen and phosphorus removals from urban wastewater.An anaerobic/aerobic/anoxic/aerobic sequencing batch biofilm reactor,called as(AO)_2-SBBR was developed through bringing an anoxic phase in the process of anaerobic/aerobic sequencing batch biofilm reactor(AO-SBBR) based on the theory of denitrifying phosphorus removal in the experiment.Simultaneous biological phosphorus and nitrogen removals in an AO-SBBR and(AO)_2-SBBR were investigated.The experiment results show that when BOD_5/TN and BOD_5/TP are 3 and 17 respectively,the simultaneous phosphorus and nitrogen removals are more effective in the(AO)_2-SBBR than that in the AO-SBBR.The removal efficiency of TP is 79.8% and the removal efficiency of TN enhances from 25.83% to 51.26%.The effluent meets the first level criteria of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant.The(AO)_2-SBBR is effective in solving the problem of low COD concentration in simultaneous biological phosphorus and nitrogen removals.The proportion of Denitrifying Phosphorus Removing Bacteria(DPB) increases from 14.82% to 63.04% in total Phosphorus Accumulating Organisms(PAOs) by introducing an anoxic phase into the AO-SBBR.It is found that low concentration nitrite nitrogen(up to 5 mg/L) is not detrimental to the anoxic phosphorus uptake and can serve as an electron acceptor such as nitrate.When the nitrite nitrogen concentration is above 10 mg/L,exposure to higher concentration nitrite can inhibit anoxic phosphorus uptake and the inhibiting effects can last for at least several hours after the nitrite exposure.