Optimizing carbon sources regulation in the biochemical treatment systems for coal chemical wastewater: Aromatic compounds biodegradation and microbial response strategies

• Published in: Water research (Oxford) 2024-06, Vol.256, p.121627-121627, Article 121627
• Main Authors: Yang, Lu, Liu, Yongjun, Li, Chen, Li, Pengfei, Zhang, Aining, Liu, Zhe, Wang, Zhu, Wei, Chunxiao, Yang, Zhuangzhuang, Li, Zhihua
• Format: Article
• Language: English
• Subjects: Aromatic compounds; Biochemical treatments; Carbon sources; Coal chemical wastewater; Metabolic characteristics
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2024.121627

•Constructed systems for the efficient degradation of aromatic compounds.•Mastered aromatic compound degradation under carbon source drive.•Explained microbial physiological responses under carbon source drive.•Revealed metabolic regulation strategies under carbon source drive.•Proposed carbon sources-driven mechanism for coal chemical wastewater treatment. The complex composition of coal chemical wastewater (CCW), marked by numerous highly toxic aromatic compounds, induces the destabilization of the biochemical treatment system, leading to suboptimal treatment efficacy. In this study, a biochemical treatment system was established to efficiently degrade aromatic compounds by quantitatively regulating the dosage of co-metabolized substrates (specifically, the chemical oxygen demand (COD) Glucose: COD Sodium acetate = 3:1, 1:3, and 1:1). The findings demonstrated that the system achieved optimal performance under the condition that the ratio of COD Glucose to COD Sodium acetate was 3:1. When the co-metabolized substrate was added to the system at an optimal ratio, examination of pollutant removal and cumulative effects revealed that the removal efficiencies for COD and total organic carbon (TOC) reached 94.61 % and 86.40 %, respectively. The removal rates of benzene series, nitrogen heterocyclic compounds, polycyclic aromatic hydrocarbons, and phenols were 100 %, 100 %, 63.58 %, and 94.12 %, respectively. Research on the physiological response of microbial cells showed that, under optimal ratio regulation, co-metabolic substrates led to a substantial rise in microbial extracellular polymeric substances (EPS) secretion, particularly extracellular proteins. When the system reached the end of its operation, the contents of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) for proteins in the optimal group were 7.12 mg/g-SS and 152.28 mg/g-SS, respectively. Meanwhile, the ratio of α-Helix / (β-Sheet + Random coil) and the proportion of intermolecular interaction forces were also increased in the optimal group. At system completion, the ratio of α-Helix / (β-Sheet + Random coil) reached 0.717 (LB-EPS) and 0.618 (TB-EPS), respectively. Additionally, the proportion of intermolecular interaction forces reached 74.83 % (LB-EPS) and 55.03 % (TB-EPS). An in-depth analysis of the metabolic regulation of microorganisms indicated that the introduction of optimal ratios of co-metabolic substrates contributed to a noteworthy upregulation in the expression of Catech