Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Sci Total Environ. 2023 Dec 20;905:167207. doi: 10.1016/j.scitotenv.2023.167207. Epub 2023 Sep 18.
Flocculants play crucial roles in sludge treatment, while the specific impact of chemical and bio-flocculants on sludge anaerobic fermentation was unknown. This study unveiled the contrasting effects of chitosan (CTS) and poly‑aluminum chloride (PAC) on volatile fatty acids (VFAs) generation during sludge fermentation. CTS supplementation resulted in 17.2 % increase in VFAs production, while PAC exposure led to 7.6 % reduction compared to the control. Further investigation revealed that CTS facilitated sludge solubilization and hydrolysis, thus providing sufficient organic substrates for VFAs generation. Additionally, environmental-friendly CTS exposure positively influenced the abundance and activity of functional anaerobes, as well as the expression of genes associated with VFAs biosynthesis. In contrast, PAC exposure resulted in the formation of larger sludge flocs, which hindered WAS solubilization and hydrolysis. Meanwhile, its potential microbial toxicity also impeded the microbial metabolic activity (i.e., genetic expressions), resulting in unsatisfactory VFAs production.
絮凝剂在污泥处理中起着至关重要的作用，而化学和生物絮凝剂对污泥厌氧发酵的具体影响尚不清楚。本研究揭示了壳聚糖（CTS）和聚氯化铝（PAC）对污泥发酵过程中挥发性脂肪酸（VFAs）生成的对比影响。与对照组相比，CTS 补充使 VFAs 产量增加了 17.2%，而 PAC 暴露则使 VFAs 产量减少了 7.6%。进一步的研究表明，CTS 促进了污泥的溶解和水解，从而为 VFAs 的生成提供了充足的有机底物。此外，环境友好型 CTS 暴露还会积极影响功能厌氧菌的丰度和活性，以及与 VFAs 生物合成相关的基因表达。相比之下，PAC 暴露会导致更大的污泥絮体形成，这会阻碍 WAS 的溶解和水解。同时，其潜在的微生物毒性也会阻碍微生物的代谢活性（即基因表达），导致 VFAs 生成不理想。
