The start-up and steady-state operation of a full-scale fixed bed digester treating citric acid production wastewater with an estimated COD/sulphate ratio of approximately 4 are described. Parallel studies at laboratory-scale with two reactors, one of which received the same high influent sulphate concentration as the full-scale plant, confirmed the finding that methanogenesis was not inhibited by the level of sulphate reduction shown to occur. After long-term operation on a high sulphate influent, the retained biomass in the laboratory and full-scale reactors displayed a very low specific methanogenic activity against propionate and butyrate. Since propionate and butyrate were barely detectable in the effluents at steady-state, their oxidation under high influent sulphate conditions may be completely or incompletely mediated by fatty-acid-utilising SRB.
Anaerobic digestion of high-sulphate-content wastewater from the industrial production of citric acid
E. Colleran, S. Finnegan, R. B. O'Keeffe; Anaerobic digestion of high-sulphate-content wastewater from the industrial production of citric acid. Water Sci Technol 1 December 1994; 30 (12): 263–273. doi: https://doi.org/10.2166/wst.1994.0623
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