Dynamics of sulfidogenesis associated to methanogenesis in horizontal-flow anaerobic immobilized biomass reactor

Two bench-scale horizontal anaerobic fixed bed reactors were tested to remove both sulfate and organic matter from wastewater. First, the reactors (R1 and R2) were supplied with synthetic wastewater containing sulfate and a solution of ethanol and volatile fatty acids. Subsequently, R1 and R2 were fed with only ethanol or acetate, respectively. The substitution to ethanol in R1 increased the sulfate reduction efficiency from 83% to nearly 100% for a chemical oxygen demand to sulfate (COD/sulfate) ratio of 3.0. In contrast, in R2, the switch in carbon source to acetate strongly decreased sulfidogenesis and the maximum sulfate reduction achieved was 47%. Process stability in long-term experiments and high removal efficiencies of both organic matter and sulfate were achieved with ethanol as the sole carbon source. The results allow concluding that syntrophism instead of competition between the sulfate reducing bacteria and acetoclastic methanogenic archaeal populations prevailed in the reactor.

[1]  Gatze Lettinga,et al.  Anaerobic treatment of sulphate-rich wastewaters , 2004, Biodegradation.

[2]  Yu-You Li,et al.  Effects of sulfate concentration and sludge retention time on the interaction between methane production and sulfate reduction for butyrate , 1994 .

[3]  W. Verstraete,et al.  Effect of COD to sulphate ratio and temperature in expanded-granular-sludge-blanket reactors for sulphate reduction , 1999 .

[4]  Yu-You Li,et al.  The behavior of sulfate-reducing bacteria in acidogenic phase of anaerobic digestion , 1998 .

[5]  Gatze Lettinga,et al.  Thermophilic sulphate reduction in upflow anaerobic sludge bed reactors under acidifying conditions , 1999 .

[6]  J. Maree,et al.  Comparison between sucrose, ethanol and methanol as carbon and energy sources for biological sulphate reduction , 2000 .

[7]  S. Chaiprapat,et al.  Effects of pH adjustment by parawood ash and effluent recycle ratio on the performance of anaerobic baffled reactors treating high sulfate wastewater. , 2008, Bioresource technology.

[8]  Daryl McCartney,et al.  Competition between methanogens and sulfate reducers: effect of COD: sulfate ratio and acclimation , 1993 .

[9]  H. Harada,et al.  Interaction between sulfate-reducing bacteria and methane-producing bacteria in UASB reactors fed with low strength wastes containing different levels of sulfate , 1994 .

[10]  G. Lettinga,et al.  Anaerobic degradation of volatile fatty acids at different sulphate concentrations , 1993, Applied Microbiology and Biotechnology.

[11]  Eugenio Foresti,et al.  Anaerobic Degradation of Synthetic Wastewaters at Different Levels of Sulfate and COD/Sulfate Ratios in Horizontal-Flow Anaerobic Reactors (HAIB) , 2007 .

[12]  G. Esposito,et al.  Perspectives of sulfate reducing bioreactors in environmental biotechnology , 2002 .

[13]  Alfons J. M. Stams,et al.  Sulfate reduction in methanogenic bioreactors , 1994 .

[14]  T. Hansen.  Metabolism of sulfate-reducing prokaryotes , 2004, Antonie van Leeuwenhoek.

[15]  Manouchehr Vossoughi,et al.  Performance of anaerobic baffled reactor treating synthetic wastewater influenced by decreasing COD/SO4 ratios , 2003 .

[16]  P. C. Sabumon.  Development of enhanced sulphidogenesis process for the treatment of wastewater having low COD/SO(4)(2-) ratio. , 2008, Journal of hazardous materials.

[17]  M. Zaiat,et al.  Performance of horizontal-flow anaerobic immobilized sludge (HAIS) reactor treating synthetic substrate subjected to decreasing COD to sulfate ratios , 1999 .

[18]  E. Colleran,et al.  Anaerobic digestion of high-sulphate-content wastewater from the industrial production of citric acid , 1994 .

[19]  Muhamad Ali Muhammad Yuzir,et al.  Anaerobic treatment of sulphate containing wastewater , 2008 .

[20]  Motoyuki Yoda,et al.  Long term competition between sulfate-reducing and methane-producing bacteria for acetate in anaerobic biofilm , 1987 .

[21]  P. L. Paulo,et al.  Effect of sulfate on methanol degradation in thermophilic (55°C) methanogenic UASB reactors , 2003 .

[22]  A. Stams,et al.  The effect of sulphate on methanol conversion in mesophilic upflow anaerobic sludge bed reactors , 2003 .

[23]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .