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 cosmetic s, pharmaceutical, medical and electronic device industries. Timely counter measures, optimization and efficacy control depend on monitoring of biofilm growth on surfaces. As water samples give no information about site and ex tent of biofilms, surface sampling is mandatory. The information about biof ilm development should be recorded on line, in real time and non destructiv ely 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. T he first two methods are based on light reflectance and detect the depositi on of reflecting material. Thus, they are not specific for biofilms but the y allow us to detect deposit formation in situ, non destructively and in re al time. The third method gives information about the chemical nature of th e deposit, allowing us to identify biological material. However, this incre ase of information requires a significantly higher technical effort. (C) 19 98 Published by Elsevier Science Ltd. All rights reserved.