Distinct effects of chemical- and bio- flocculants on the sludge acidogenic fermentation for volatile fatty acids production by affecting the acidogenic steps, microbial community structure and metabolic functions

Jingyang Luo; Xue Xia; Yuxiao Li; Shiyu Fang; Feng Wang; Xiaoshi Cheng; Leiyu Feng; Wenxuan Huang; Yang Wu

doi:10.1016/j.scitotenv.2023.167207

Distinct effects of chemical- and bio- flocculants on the sludge acidogenic fermentation for volatile fatty acids production by affecting the acidogenic steps, microbial community structure and metabolic functions

Sci Total Environ. 2023 Dec 20:905:167207. doi: 10.1016/j.scitotenv.2023.167207. Epub 2023 Sep 18.

Authors

Jingyang Luo¹, Xue Xia¹, Yuxiao Li¹, Shiyu Fang¹, Feng Wang¹, Xiaoshi Cheng¹, Leiyu Feng², Wenxuan Huang³, Yang Wu⁴

Affiliations

¹ 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.
² State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
³ 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. Electronic address: hwx864493861@163.com.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: wuyang1026@tongji.edu.cn.

PMID: 37730033
DOI: 10.1016/j.scitotenv.2023.167207

Abstract

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.

Keywords: Chitosan; Metabolic function; Microbial toxicity; Poly‑aluminum chloride; Volatile fatty acids.

MeSH terms

Fatty Acids, Volatile / metabolism
Fermentation
Hydrogen-Ion Concentration
Microbiota*
Sewage* / chemistry

Substances

Sewage
Fatty Acids, Volatile