Microbial sulphate reduction during anaerobic digestion: EGSB process performance and potential for nitrite suppression of SRB activity.
The present study investigated mesophilic anaerobic treatment of sulphate-containing wastewater in EGSB reactors and assessed the inclusion of nitrite in the reactor influent as a method for control of biological sulphate reduction. Two EGSB reactors, R1 and R2, were operated for a period of 581 days at varying volumetric loading rates, COD/SO4(2-) ratios and influent nitrite concentrations (R2 only). COD removal efficiencies of > 93% were achieved in both reactors at influent sulphate concentrations of up to 3,000 mg l(-1). A two-fold increase in the influent sulphate concentration, giving an influent COD/SO4(2-) ratio of 2, resulted in a reduction in reactor COD removal efficiency to 84% and 89%, in R1 and R2, respectively. Despite inclusion of nitrite in the R2 influent at concentrations up to 500 mg NO2-N l(-1), sulphate reduction proceeded similarly in R2 and R1, suggesting the ineffectiveness of nitrite as a potential inhibitor of SRB
O'Reilly
C
C
Environmental Microbiology Research Unit, Department of Microbiology, National University of Ireland, Galway, Ireland. coreilly@caw.ie
Colleran
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E
D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D019149:Bioreactors / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D019640:Methanosarcinales / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D018613:Microscopy, Confocal; D009573:Nitrites / Q000494:pharmacology*; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology; D013431:Sulfates / Q000378:metabolism*; D016999:Sulfur-Reducing Bacteria / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D014865:Waste Disposal, Fluid
D009573:Nitrites; D012722:Sewage; D013431:Sulfates