DO对除磷过程的长期影响

为研究溶解氧(DO)对除磷过程的长期影响,采用序批式间歇反应器(SBR),通过设置好氧阶段DO的不同(5.5～7.0 mg/L和0.5～1.5 mg/L),系统地考察长期运行在这两种DO水平下强化生物除磷系统(EBPR)除磷过程的特点.结果表明:在pH 7.2～7.6,温度(23±0.5)℃时,高DO对放磷和吸磷两个阶段均会产生负面影响.其厌氧阶段的放磷量比低DO情况下要少43.08%.吸磷过程在好氧阶段初始30 min内进行得最快,该期间内高低DO污泥的最大比吸磷速率分别为6.27和11.45 mg.g-1.h-1,前者比后者少45.24%.分析认为,过度曝气导致的聚磷菌体内聚β羟基丁酸盐(PHB)的不足和过多的进水碳源被用作反硝化,是本试验高DO状态下除磷性能恶化的主要原因.高DO在抑制丝状菌膨胀方面并不比低DO占有明显的优势,污泥除磷性能的改善往往伴随着污泥沉降性的好转.

Long-term effect of DO on phosphorus removal process

To study the long-term effect of dissolved oxygen(DO) on phosphorus removal process,the characteristics of enhanced biological phosphorus removal(EBPR) under the DO level of 5.5-7.0 mg/L and 0.5-1.5 mg/L were investigated systematically using sequencing batch reactor(SBR).The results showed that,when pH was in 7.2-7.6 and temperature was at(23±0.5)℃,high DO had adverse impact on both phosphorus release process and phosphorus uptake process.The amount of released phosphorus in anaerobic period was 43.08% lower than that under low DO condition.Phosphorus uptake process went fast during the initial 30 min in aerobic period.The maximum specific phosphorus uptake rate was 6.27,11.45 mg·g-1·h-1 under high DO and low DO conditions,respectively.Analysis indicated that the main reason of deterioration of phosphorus removal process was deficiency of poly-β-hydroxybutyrate(PHB) caused by excessive aeration and more influent carbon source used for denification process.High DO did not have obvious advantage on restraining filamentous sludge bulking than low DO.The improvement of phosphorus removal was usually associated with the improvement of sludge settleability.