In a mesophilic (30-35 degrees C), sulphidogenic, ethanol-fed expanded-granular-sludge-blanket reactor, sulphate, at loading rates of up to 10.0-12.0 g Sl(-1) day(-1) was removed with an average efficiency of more than 80%. The pH was between 7.7 and 8.3 and the maximal total dissolved sulphide concentration was up to 20 mM S (650 mg S/l). The alkaline pH was maintained by either a pH-control unit with sodium hydroxide or by stripping part of the sulphide and CO2 from the recycle with nitrogen gas. The superficial upstream liquid velocity (v(up)) was 3.0-4.5 m/h. The ratio of ethanol to sulphur was near stoichiometry. At alkaline pH, the activity of the acetotrophic sulphate-reducing bacteria, growing on acetate, was strongly enhanced, whereas at pH below 7.7 the acetotrophic sulphate-reducing bacteria were inhibited by aqueous H2S. With regard to the removal efficiency and operational stability, external stripping with N-2 and pH control were equally successful.