酵母菌降解胞外聚合物提升剩余活性污泥的脱水性能

剩余污泥的脱水性能直接影响到污泥处置的效果和成本,提升污泥脱水性是污泥减量化的重要途径.本研究提出利用复合酵母菌群降解剩余污泥胞外聚合物(EPS)来提升污泥脱水性能的方法.首先评价了复合酵母菌群对灭菌后EPS中各组分的降解效果;继而将混合酵母细胞接入剩余污泥中进行曝气,考察了酵母菌对污泥脱水性的提升效能.研究结果表明,酵母菌对提取的EPS中蛋白质、多糖和核酸的降解效果明显,振荡培养72 h内最多分别降低了(60. 43±2. 73)%、(18. 94±2. 39)%和(48. 30±3. 37)%.向2 L剩余污泥中接入1. 5 g混合酵母菌湿菌体进行曝气,24 h后污泥的毛细吸水时间(CST)下降了(17. 19±1. 16)%,比对照组多下降了(7. 03±1. 35)%;与此同时污泥中EPS总量比对照污泥多下降了(17. 46±3. 91)%,表明酵母菌可以通过原位降解污泥中EPS来提高污泥的脱水性能.

Improvement of the Dewaterability of Excess Activated Sludge with Mixed Yeasts by Degrading Extracellular Polymeric Substances

The dewaterability of excess sludge directly affects the efficiency and cost of sludge disposal, and improving sludge dewaterability is a crucial way to reduce sludge volume. This study proposes a method to improve the dewaterability of residual sludge by using mixed yeast strains to degrade extracellular polymeric substances (EPS) in activated sludge. Firstly, the mixed cells of three yeast strains were injected into the sterilized EPS solution to investigate the degradation efficiency of EPS components. Secondly, the mixed yeast cells were supplied into the residual sludge, which was aerated for several hours while the sludge dewaterability was evaluated. The results showed that the degradation efficiencies of yeast to proteins, polysaccharides, and nucleic acids in EPS were evident, and reductions of (60.43±2.73)%, (18.94±2.39)%, and (48.30±3.37)% were achieved, respectively, within 72 hours'' oscillating cultivation. The capillary suction time (CST) of the sludge decreased by (17.19±1.16)% after aeration, with 1.5 g mixed yeast wet cells added into 2 L excess sludge, (7.03±1.35)% more than that of the control test after 24 hours. Meanwhile, the total amount of EPS in sludge decreased by (17.46±3.91)% more than that in the control sludge, indicating that the yeast can improve the sludge dewaterability in-situ by degrading EPS in sludge.