Co-substrate promoting the biodegradation of refractory DOM in semi-coking wastewater: DOM evolution and microbial community. Issue 1 (February 2023)

• Record Type: Journal Article
• Authors: Cai, Min-Hui; Tian, Ye-Chao; Li, Ai-Min; Li, Yan; Han, Yu-Ze; Li, Jun; Sun, Hong-Fang; Wang, Xin; Zhou, Qing; Li, Wen-Tao
• Is Part Of: Journal of environmental chemical engineering. Volume 11:Issue 1(2023)
• Publication Date: 2023-02
• Subjects: Co-metabolism -- Refractory dissolved organic matter -- Size exclusion chromatography -- PICRUSt2 analysis -- Microbial community structure; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.109043
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Semi-coking wastewater treatment has become a difficult issue because of its complexity, heterogeneity and toxicity. In this study, co-metabolism with ethanol or sodium acetate as co-substrates was applied to improve the biological degradation of refractory dissolved organic matter (DOM) in semi-coking wastewater. Kinetic model simulation results indicated that both co-substrates addition improved COD removal efficiency and biodegradation rate. Excitation-emission matrix (EEM) spectroscopy and size exclusion chromatography with organic carbon detector (SEC-OCD) analysis were applied to evaluate the DOM biodegradation in terms of fluorescence and molecular weight (MW). Although co-substrates resulted in a comparable enhanced removal efficiency of protein-like and humic-like fluorophores, there are distinct differences in their specific protein-like fluorescent peaks (Peak C1&C2). Ethanol addition was more conducive to the removal of humic substance with apparent molecular weight (AMW) ranging from 1.1 kDa to 20 kDa. Acetate addition resulted in higher removal of building blocks of humic substances (BB, AMW 0.45–1.1 kDa) and proteinaceous biopolymers (BP, AMW >20 kDa). Co-metabolism triggered the shift of microbial community structure and metabolic functions. Using co-occurrence network analysis, nine keystone genera were identified, which maintained the functional stability of bacterial community responding to organic toxicants stress. LefSe analysis elucidated that the potential major genera involved in refractory organics biodegradation with acetate addition were Stenotrophomonas (40.3%) and Pseudomonas (21.2%), while Pseudoxanthomonas (10.4%) with ethanol addition. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) analysis showed that benzoate, styrene, xylene and naphthalene degradation pathway were enhanced by acetate addition as compared to ethanol. Graphical Abstract: ga1 Highlights: Co-metabolism improved refractory DOM degradation in real semi-coking wastewater. AMW changes of DOM with co-substrates dosage were characterized by SEC-OCD. Co-substrates impacted the removal of protein/humic-like fluorophores. LefSe analysis and co-occurrence analysis of bacteria were performed. Xenobiotics degradation pathway was enhanced with co-substrates dosage.