Abstract
In activated sludge treatment facilities, the waste water is purified by microbial metabolic processes.
In order to understand the corrosion of SUS304 stainless steels in this facilities, investigation by microbial analysis and electrochemical measurements was conducted.
Aerobic bacteria were detected in corroded weld parts. Open circuit potentials (Eoc) of corroded facilities were more noble than that of the stainless steel in controlled waste water and that of no corrosion facilities. Repassivation potentials for crevice corrosion (ER,CREV) of the SUS304 stainless steel were measured in the laboratory and a Eoc > ER,CREV relation was confirmed.
It was considered that the cause of the corrosion was the increase of the potential of SUS304 stainless steels by microorganisms action and a formation of crevice by biofilm.
