Antagonistic effects of surfactants and CeO2 nanoparticles co-occurrence on the sludge fermentation process: Novel insights of interaction mechanisms and microbial networks

• Published in: Journal of hazardous materials 2022-09, Vol.438, p.129556-129556, Article 129556
• Main Authors: Luo, Jingyang, Cao, Wangbei, Guo, Wen, Fang, Shiyu, Huang, Wenxuan, Wang, Feng, Cheng, Xiaoshi, Du, Wei, Cao, Jiashun, Feng, Qian, Wu, Yang
• Format: Article
• Language: English
• Subjects: Anaerobic fermentation; Microbial metabolic networks; Nanoparticles; Short-chain fatty acids; Surfactants
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129556

Various pollutants commonly co-exist in the waste active sludge (WAS), but the interactive effects and mechanisms of co-occurrence pollutants on the WAS treatment remain unclear. This work mainly investigated the impacts of different surfactants (i.e., HTAB and SDBS) and CeO2 nanoparticles (NPs) co-occurrence on the WAS fermentation for short-chain fatty acids (SCFAs) production, and found that the CeO2 NPs coexisting with surfactants caused antagonistic effects on the SCFAs generation (10.7% and 33.9% inhibition by HTAB and SDBS, respectively). The surfactants and CeO2 NPs co-occurrence restrained the solubilization, hydrolysis, and acidification steps simultaneously. Moreover, the functional hydrolytic-acidogenic bacterial (e.g., Haliangium and Bacteroidetes sp.) and the microbial metabolic networks involved in extracellular hydrolysis (e.g., pepd and NEU1), substrate metabolism (e.g., ALDO and asdA), and fatty acid biosynthesis (e.g., aarC and pct) were all downregulated by 4.3–53.8% in the reactors with surfactants and CeO2 NPs co-occurrence. The presence of surfactants enhanced the dispersibility and stability of CeO2 NPs and the Ce dissolution (1.5–3.0 times higher). Also, surfactants contributed to the WAS disintegration, which could improve the interactive chances of microorganisms entrapped in WAS and CeO2 NPs by promoting the transportation channels, and therefore aggravated the toxicity towards anaerobic species. [Display omitted] •Surfactants and CeO2 NPs co-occurrence caused antagonistic effects on SCFAs yield.•The WAS solubilization, hydrolysis, and acidification steps were all inhibited.•The microbial community and metabolic traits for SCFAs yield were down-regulated.•Surfactants enhanced the dispersity and stability of CeO2 NPs and Ce4+ dissolution.•The mechanisms for aggravated toxicity of surfactants and CeO2 NPs were unveiled.