MICROBIAL COLONIZATION OF THE SURFACE OF STAINLESS-STEEL COUPONS IN ADEIONIZED WATER-SYSTEM

Stainless steel coupons immersed in a deionized water system for about 7 months were analyzed for the presence of biofouling and microbially -influenced corrosion bacteria. Aerobic oligotrophs were dominant whil e other microorganisms including sulfate-reducing bacteria were presen t in relatively low numbers or were absent. A wide variety of microorg anisms were detected on the coupon surfaces by scanning electron micro scopy. The growth of microorganisms was patchy and in the form of smal l colonies attached to the surfaces with a confluent film of extracell ular polysaccharide or fine strands. Corrosion products, such as sulph ur, could not be detected. The potential for biofouling and microbiall y-influenced corrosion exists in the deionized water system since olig otrophic microorganisms would multiply and form a biofilm in which con ditions conducive to the growth of microbially-influenced corrosion ba cteria could be created.