Insight into the responses of the anammox granular sludge system to tetramethylammonium hydroxide (TMAH) during chip wastewater treatment

• Published in: Environmental research Vol. 263; no. Pt 2; p. 120099
• Main Authors: Zhao, Andong, Li, Jun, Gao, Peng, Tang, Peng, Liu, Tingting, Zhang, Xin, Liu, Xuming, Chen, Cong, Zhang, Zehao, Zheng, Zhaoming
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15.12.2024
• Subjects: Extracellular electron transfer; Extracellular polymeric substances; Oxidative stress; Tetramethylammonium hydroxide; Extracellular polymeric substances; Oxidative stress; Tetramethylammonium hydroxide; Extracellular electron transfer
• ISSN: 0013-9351; 1096-0953; 1096-0953
• DOI: 10.1016/j.envres.2024.120099

Tetramethylammonium hydroxide (TMAH), an extensively utilized photoresist developer, is frequently present in ammonium-rich wastewater from semiconductor manufacturing, and its substantial ecotoxicity should not be underestimated. This study systematically investigated the effects of TMAH on the anammox granular sludge (AnGS) system and elucidated its inhibitory mechanisms. The results demonstrated that the median inhibitory concentration of TMAH for anammox was 84.85 mg/L. The nitrogen removal performance of the system was significantly decreased after long-term exposure to TMAH (0–200 mg/L) for 30 days (p < 0.05), but it showed adaptability to certain concentrations (≤50 mg/L). Concurrently, the stability of the granules decreased dramatically, resulting in the breakdown of AnGS. Further investigations indicated that TMAH exposure increased the secretion of extracellular polymeric substances but weakened their defense function. The increase in reactive oxygen species resulted in damage to the cell membrane. Reduced activity of anammox bacteria, impeded electron transfer, and changes in enzyme activity suggested that TMAH affected the metabolic activity. Microbiological analysis revealed that TMAH caused a decrease in the abundance of anammox bacteria and a weakening of symbiotic interactions within the microbial community. These results provide valuable guidance for the AnGS system application in chip wastewater treatment. [Display omitted] •The effects of TMAH on the AnGS system were first studied.•IC50 of TMAH was detected to be 84.85 mg/L.•EPS secretion is a key strategy of the AnGS system to cope with TMAH stress.•TMAH impaired extracellular electron transport ability of the AnGS system.•The AnGS system showed an adaptive trend when TMAH ≤50 mg/L.