Abstract:

In order to study the effects of anoxic condition on release of phosphorus in an enhanced system for phosphorus removal with granular sludge, batch tests were carried out using acetate and propionate(carbon molar ratio=2∶1)as carbon source and adding different amount of NO^-₃-N(0, 20, 30, 50 and 75 mg·L^-1, pH=8.0)and NO^-₂-N(10, 20, 40 and 60 mg·L^-1, pH=7.0, 7.5 and 8.0)in initial anaerobic stage.The results showed that addition of NO^-₃-N and NO^-₂-N had no obvious inhibition on release of phosphorus.Absorption of fatty acids(VFAs), phosphorus release and denitrification took place simultaneously,and absorption rate increased while release rate of phosphorus decreased because of competition between denitrifying bacteria and phosphorus accumulating microbial granule(PAOs)for carbon source.The results of batch tests at various NO^-₂-N concentration and at different pH showed that FNA, rather nitrite, had a strong stimulation effect on P-release and the rate of P-release increased by 4 times when FNA concentration was higher than 0.004 mg HNO₂-N·L^-1.Meanwhile, FNA had obvious suppression on absorption of VFA and synthesis of PHA, and the absorption rate and synthesis mass decreased by 53% and 70%, respectively.Based on analysis of energy generation and metabolism of PAOs as well as toxic action of nitrite, the mechanism stimulating P-release of FNA was, in presence of free nitrous acid, that PAOs was required to release more energy to provide adequate proton motive force(pmf).

摘要：

以除磷颗粒污泥为研究对象，采用批次试验，以混合丙酸和乙酸（2∶1）为外加碳源，在厌氧起始阶段投加不同浓度的NO^-₃-N（0, 20, 30, 50和75 mg·L^-1, pH=8.0）和NO^-₂-N（10，20，40和60 mg·L^-1, pH=7.0, 7.5和8.0），研究缺氧环境对颗粒污泥强化除磷系统释磷的影响。结果表明，硝态氮的投加对聚磷菌释磷无明显抑制，系统中VFA的吸收、磷的释放和硝态氮的反硝化同时发生，挥发性脂肪酸（