Removal of 2-mercaptobenzothiazole by activated sludge: a cautionary note

The removal of 2-mercaptobenzothiazole (MBT) from solution was noted in die-aways in the presence of several activated sludges. The most rapid removal was noted with an industrial sludge, however, MBT was removed as rapidly by heat-killed as by “live” activated sludge. MBT could be removed from solution by other activated sludges but this occurrence is rather erratic. No evidence was obtained for biodegradation of MBT and it is suggested that this removal from solution is non-enzymic but is related to the presence of the sludge. Possible mechanisms are discussed.