Recovery of Metals from Stainless-Steel Wastewater for Their Catalytic Application in the Biodegradation of 2,4,6-Trichlorophenol

2,4,6-Trichlorophenol (TCP) is a widely used compound in various industrial sectors, posing a significant threat to both environmental and human health. To address this issue, a novel treatment system is proposed, employing anaerobic sludge enriched with metals recovered from a metallurgical effluent as a biocatalyst for TCP biodegradation. The enrichment of anaerobic sludge with recovered metals (1%, wt/wt) enhanced TCP removal efficiency, achieving 86.7% degradation after 24 h of incubation, compared to only 72.1% in the unamended control (38% increase in degradation rate). Metabolites analysis revealed the formation of 2,4-dichlorophenol, 4-chlorophenol, and phenol as intermediate degradation products, which were generated and subsequently degraded more rapidly in the enriched system than in the control. The stoichiometric release of chloride ions further confirmed reductive dehalogenation as the primary degradation pathway. Additionally, the presence of Fe(III) minerals is proposed to contribute as electron acceptors, thereby enhancing the degradation process. This treatment strategy is consistent with the principles of circular economy. It demonstrates the potential reuse of metals recovered from industrial wastewater to serve as biocatalysts in anaerobic treatment systems, which may promote the removal of a broad range of emerging contaminants. This approach could be particularly effective in the treatment of wastewaters from hospitals, as well as the pharmaceutical and chemical industries.

Graphical Abstract