Monitoring and disinfection of biofilm-associated sulfate reducing bacteria on different substrata in a simulated recirculating cooling tower system

Abstract

Microbial biofilm and corrosion in cooling systems are the most common problems that damage expensive equipment, cause loss of production, and increase maintenance costs. Sulfate reducing bacteria were considered the major bacterial group involved in microbiologically influenced corrosion (MIC). We investigated the survival and enumeration of biofilm-associated SRB on coupons of galvanized steel, stainless steel, and copper, which are materials used in the manufacturing of cooling systems. We also investigated the effect of monochloromine on SRB as in mixed-species mature biofilms formed on coupons by simulating recirculating cooling water conditions, due to the better penetration feature in biofilms than the residual chlorine. It was concluded that SRB count increased with time in bulk water and the surfaces (P < 0.01). Experimental results supported by statistical analyses show that monochloromine is poorly effective on SRB colonies formed on galvanized and stainless steel surfaces.