游离亚硝酸对好氧/延长闲置序批式反应器除磷性能的影响

以合成废水为研究对象,在好氧/延长闲置序批式反应器中研究不同浓度游离亚硝酸对系统除磷性能的影响.通过分析闲置期聚磷水解及微生物体内各储能物质的变化及不同反应器的除磷效果,探究其可能存在的影响机理.结果表明,游离亚硝酸浓度为5.13×10-5mg·L-1时对反应器除磷效果及沉降能力抑制不明显,而当游离亚硝酸浓度达到5.13×10-4mg·L-1时,磷的平均去除率降至40.5%,反应器中出现严重的污泥膨胀,污泥沉降指数值最高达310 mL·g-1.典型周期分析表明,游离亚硝酸可影响聚磷菌对碳源的吸收和胞内聚羟基脂肪酸酯的合成,进而影响好氧吸磷及闲置期聚磷水解.恢复试验表明,当游离亚硝酸浓度高于2.57×10-4mg·L-1时,撤销影响后系统的除磷能力和沉降性能虽有明显回升,但无法恢复至初始水平.

Effect of free nitrous acid on biological phosphorous removal in aerobic/extended-idle sequencing batch reactor

The effect of free nitrous acid (FNA) on biological phosphorous removal in aerobic/extended-idle sequencing batch reactor was investigated by feeding synthetic wastewater containing different concentrations of FNA. Phosphorus removal performances in the reactors were compared, and poly-phosphate hydrolysis in the extended-idle period and variations of intracellular energy storage material were analyzed to explore the possible inhibitory mechanism. The experimental results showed that FNA had no obvious influence on reactor performance at the concentration of 5.13×10^-5 mg·L^-1, whereas a critical inhibition on phosphorous can be observed when FNA at the condition of 5.13×10^-4 mg·L^-1. Under this condition,the average phosphorus removal efficiency decreased to 40.5%. Besides, a severe activated sludge bulking occurred and the highest sludge volume index value reached up to 310 mL·g^-1. Analysis on a typical cycle of the reactors suggested FNA can inhibit carbon source uptake and intracellular polyhydroxyalkanoates synthesis of phosphate accumulating organisms, leading to serious inhibition of aerobic phosphorus uptake and poly-phosphate hydrolysis in the extended-idle period. Recovery tests indicated that system performances can be improved when FNA was removed, but cannot reach their initial states after an exposure to FNA higher than 2.57×10^-4 mg·L^-1.