Optimisation of sulphate reduction in a methanol-fed thermophilic bioreactor

• Published in: Water research (Oxford) Vol. 36; no. 7; pp. 1825 - 1833
• Main Authors: Weijma, Jan, Bots, Eelco A.A., Tandlinger, Gabrielle, Stams, Alfons J.M., Pol, Look W.Hulshoff, Lettinga, Gatze
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2002; Elsevier Science
• Subjects: afvalwaterbehandeling; ANAEROBIC TREATMENT; anaërobe behandeling; Applied sciences; Bacteria (Methane); Biological and medical sciences; Biological treatment of waters; Bioreactors - microbiology; Biotechnology; Carbon - metabolism; Competition; EGSB; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Industrial wastewaters; METANOL; Methane - metabolism; Methanogenesis; METHANOL; Methanol - metabolism; Oxidation-Reduction; Pollution; REDUCCION; reductie; REDUCTION; Sewage - chemistry; slib; SLUDGES; SULFATE; sulfaten; sulfates; Sulfates - metabolism; SULFATOS; Sulphate reduction; SULPHATES; Thermophilic; Time Factors; TRAITEMENT ANAEROBIQUE; TRATAMIENTO ANAEROBICO; WASTE WATER TREATMENT; Wastewaters; Water Purification - methods; Water treatment and pollution; Competition; EGSB; Thermophilic; Sulphate reduction; Methanogenesis; Methanol; Anaerobiosis; Microbial activity; Sulfate-reducing bacteria; Bioreactor; Sulfatoreduction; Industrial waste water; Methanogenic bacteria; Thermophily; Waste water purification; Biological purification
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(01)00390-6

Several methods were tested to optimise sulphate reduction and minimise methane formation in thermophilic (65°) expanded granular sludge bed reactors fed with a medium containing sulphate and methanol. Lowering the pH from 7.5 to 6.75 resulted in a rapid decrease of methane formation and a concomitant increase in sulphate reduction. The inhibition of methane formation was irreversible on the short-term. Lowering the COD/SO 4 2− ratio (COD: chemical oxygen demand) from 6 to 0.34 (g/g) rapidly favoured sulphate reduction over methanogenesis. Continuous addition of 2 g L −1 2-bromoethanesulphonate was ineffective as complete inhibition of methanogenesis was obtained only for two days. Inhibition of methanogens by sulphide at pH 7.5 was only effective when the total sulphide concentration was above 1200 mg S L −1. For practical applications, a relatively short exposure to a slightly acidic pH in combination with operating the reactor at a volumetric methanol-COD loading rate close to the maximum volumetric sulphide-COD formation rate.