Mesophilic (30 °C) upflow anaerobic sludge bed reactors were fed with an influent containing sulphate (2 g l-1) and methanol (1.33 g l-1). More than 90% of the methanol was mineralised to methane, while only ˜5–10% of the methanol was used for sulphate reduction. This pattern was independent of short-term pH variations in the range from 5 to 8, addition of acetate as co-substrate and type of granular seed sludge (methanogenic and sulphidogenic). On average 0.4 gSO42- lreactor-1 per day was reduced under these conditions. Also applying 1-day temperature shocks of 65 or 80 °C did not stimulate sulphate reduction. Sulphite, added as an alternative acceptor, appeared to be disproportionated to sulphate and sulphide. Results show that methanol conversion to methane in upflow sludge bed reactors is very stable in the presence of sulphate. This suggests that under mesophilic conditions, methanol is not a suitable feedstock for sulphate-reducing processes in such reactors.
- thermophilic methanosarcina
- carbon source