Abstract
The formation of microbial films attached to surfaces of titanium and polycarbonate membranes in condenser tubes exposed to water from the River Thames is described. The primary film is composed of microorganisms, their extracellular polymers and particulate matter. Initial colonization was by solitary bacteria, followed by colony formation and the entrapment of particulate matter in the extracellular polymers produced by the bacteria. After 15 days solitary Protozoa were observed and colonial forms after 30 days. The results show that titanium surfaces supported a rich and varied population of microorganisms giving rise to a thick primary film, which may adversely affect heat transfer in condenser tubes.