Monitoring of fouling and biofouling in technical systems

Biofouling is a problem in many different industrial fields, causing damage of product or interfering with production processes, ranging from drinking and purified water systems to paper manufacture, heat exchange or cosmetics, pharmaceutical, medical and electronic device industries. Timely countermeasures, optimization and efficacy control depend on monitoring of biofilm growth on surfaces. As water samples give no information about site and extent of biofilms, surface sampling is mandatory. The information about biofilm development should be recorded on line, in real time and non destructively in order to permit the kinetics of deposition or removal to be followed. Three physical methods are presented here: i) a fiber optical device, ii) a differential turbidity measurement device, and iii) an FTIR flow cell. The first two methods are based on light reflectance and detect the deposition of reflecting material. Thus, they are not specific for biofilms but they allow us to detect deposit formation in situ, non destructively and in real time. The third method gives information about the chemical nature of the deposit, allowing us to identify biological material. However, this increase of information requires a significantly higher technical effort. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.