Microbial processes and bacterial populations associated to anaerobic treatment of sulfate-rich wastewater

• Published in: Process biochemistry (1991) 2010-02, Vol.45 (2), p.164-170
• Main Authors: Sarti, Arnaldo, Pozzi, Eloisa, Chinalia, Fabio A., Ono, Alexandre, Foresti, Eugenio
• Format: Article
• Language: English
• Subjects: Anaerobic reactor; Bacteria; Biofilm; Biomass; Concentration (composition); DNA library; Ethyl alcohol; Microorganisms; Mineral coal; Phylogenetic characterization; Reduction; Sulfate reduction; Sulfates; Waste water
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2009.09.002

A pilot-scale (1.2 m 3) anaerobic sequencing batch biofilm reactor (ASBBR) containing mineral coal for biomass attachment was fed with sulfate-rich wastewater at increasing sulfate concentrations. Ethanol was used as the main organic source. Tested COD/sulfate ratios were of 1.8 and 1.5 for sulfate loading rates of 0.65–1.90 kgSO 4 2−/cycle (48 h-cycle) or of 1.0 in the trial with 3.0 gSO 4 2− l −1. Sulfate removal efficiencies observed in all trials were as high as 99%. Molecular inventories indicated a shift on the microbial composition and a decrease on species diversity with the increase of sulfate concentration. Beta-proteobacteria species affiliated with Aminomonas spp. and Thermanaerovibrio spp. predominated at 1.0 gSO 4 2− l −1. At higher sulfate concentrations the predominant bacterial group was Delta-proteobacteria mainly Desulfovibrio spp. and Desulfomicrobium spp. at 2.0 gSO 4 2− l −1, whereas Desulfurella spp. and Coprothermobacter spp. predominated at 3.0 gSO 4 2− l −1. These organisms have been commonly associated with sulfate reduction producing acetate, sulfide and sulfur. Methanogenic archaea ( Methanosaeta spp.) was found at 1.0 and 2.0 gSO 4 2− l −1. Additionally, a simplified mathematical model was used to infer on metabolic pathways of the biomass involved in sulfate reduction.