The Fate of Benzothiazole‐2‐Sulphonic Acid in Biologically Treated Industrial Effluents

Benzothiazole‐2‐sulphonic acid is capable of being completely degraded by micro‐organisms, though in this study, all attempts to isolate a pure culture capable of growing in a liquid benzothiazole‐2‐sulphonic acid–mineral‐salts medium were unsuccessful. Both the mixed culture which was capable of growing in this medium and sludge from an activated sludge plant treating an influent containing benzothiazole‐2‐sulphonic acid, would also oxidize benzothiazole, 2‐hydroxybenzothiazole and 2‐mercaptobenzothiazole. The sulphur and nitrogen originally present in benzothiazole‐2‐sulphonic acid were quantitatively converted to sulphate and ammonia, respectively. Die‐away tests indicate that benzothiazole‐2‐sulphonic acid was only immediately degraded by populations which previously had been exposed to this compound.