Tannery wastewater HLFCR. Integrated biological system for remediation and valorization of tannery wastewater: focus on microbial communities responsible for methanogenesis and sulfidogenesis

The composition and function of sulfate reducing bacteria (SRB) and methanogenic archaea (MA) in hybrid linear flow channel reactors (HLFCRs) and anaerobic sequencing batch reactors (ASBRs) operated in series for remediation of tannery wastewater were compared. The primary physicochemical drivers of SRB and MA were NH4+ (BEST: r=0.499) and HS-, Si, and pH (BEST: r=0.709), respectively. Metabolic capabilities of SRB such as the ability to degrade and/or utilize proteins and/or amino acids as substrates, halotolerance and/or NH3/NH4+ tolerance explained their presence in tannery effluent. While sulfidogenesis dominated in the HLFCRs, both sulfidogenesis and methanogenesis took place concurrently in the ASBRs without detrimental effects on process efficiency (max 321 mLCH4/gCODconsumed, 58.9% biogas CH4). In the ASBRs, aceticlastic methanogenic genera (Methanosarcina and Methanosaeta) dominated the MA, while both incomplete oxidizing (Desulfovibrio, Desulfomicrobium) and complete oxidizing (Desulfosarcina, Desulfobacterium) genera dominated the SRB. In contrast, 2 incomplete oxidizers Desulfovibrio, Desulfomicrobium) dominated in the HLFCRs.