The effect of alkaline pH conditions on a sulphate reducing consortium from a Danish district heating plant

Abstract

This study demonstrated that a non‐alkaliphilic sulphate reducing bacterial (SRB) consortium could survive the alkaline environment in the circulation water of a Danish District Heating Plant. The plant was experiencing corrosion, and SRB were postulated to be responsible. A bacterial consortium containing mesophilic SRB was enriched in vials inoculated with the plant circulation water. A batch experiment illustrated the ability of the SRB to survive a pH of 10.5. The same SRB produced sulphide at a pH of 9.3, when the pH in the batch vials was lowered by other bacteria present in the consortium. Another experiment demonstrated that, when protected in a biofilm, the same SRB consortium produced sulphide at a bulk fluid pH of 10.2. These results could be implemented as part of a SRB control strategy in the field.