温度和污泥浓度对碱性条件下剩余污泥水解酸化的影响

Effect of temperature and sludge concentration on hydrolysis and acidification of waste activated sludge under alkaline condition

挥发性脂肪酸(VFAs)是脱氮除磷过程中易于利用的碳源。剩余污泥在碱性条件下发酵能产生大量的VFAs,而温度和污泥浓度是影响剩余污泥发酵的两个重要因素,为此考察了厌氧环境,温度15℃和35℃,pH为10的条件下,剩余污泥挥发性悬浮污泥浓度(VSS为1.708～11.049 g/L)对水解酸化的影响,为实现剩余污泥的资源化提供理论依据。研究得出如下结论:污泥浓度对剩余污泥溶解性化学需氧量(SCOD)溶出率影响不大。低污泥浓度和高污泥浓度均不利于剩余污泥产酸,最佳产酸的污泥浓度为8.540 g/L。各污泥浓度条件下产生的6种挥发性有机酸中乙酸的比例总是最大,且低污泥浓度条件下乙酸的百分含量要高于高污泥浓度条件下。温度对高污泥浓度条件下污泥的最大SCOD溶出量影响较大,而对低污泥浓度条件下污泥最大的产酸量影响较大。无论15℃还是35℃,中等污泥浓度对氨氮的释放量影响不大,35℃条件下污泥浓度对正磷酸盐的释放要比15℃条件下大。

Volatile fatty acids （VFAs） are suitable carbon sources for nitrogen and phosphorus removal. A large amount of VFAs can be produced in the alkaline fermentation process of WAS. Temperature and sludge concentration are two critical factors for waste activated sludge （WAS） fermentation, therefore the effect of temperature and sludge concentration on hydrolysis and acidification of WAS was investigated at 15℃, 35℃ and pH = 10 under anaerobic con- dition. The results showed that soluble chemical oxygen demand （SCOD） production yields were impacted little by sludge concentration. Low or high sludge concentrations were disadvantage for acid production, the best sludge concentration for acid production was VSS = 8.54 g/L. At any sludge concentration investigated, acetic acid dominated in the six volatile short chain fatty acids produced by sludge fermentation, besides the percentage of acetic acids were higher at low sludge concentration than high sludge concentration. Temperature impacted significantly on the hydrolysis of WAS with higher sludge concentration, but it impacted significantly on the acidification of WAS with lower sludge concentration. Medium sludge concentration at 6.832,8. 540 g/L influenced little on ammonia release at 15℃ and 35℃, sludge concentration influenced more significantly on phosphorus release at 35℃than at 15℃ .