Current Technologies for On-line Monitoring of Quality of Water in Distribution Systems

Mirnader Ghazali and Edward McBean


Increased risk of drinking water contamination has increased interest in the capabilities to detect the presence of microbiological and/or chemical contamination of drinking water supplies on a real-time basis. As well, indirect measurements such as pH, and turbidity to detect pathogens do not guarantee the safety of drinking water because pathogens, and especially protozoa and viruses, are not well correlated to these indirect measures. Routine methods for culturing indicator micro-organisms need considerable elapsed time. Therefore, there is definitely a need for real-time detection of an ‘event’ in drinking water distribution systems due to the presence of a contaminant, followed by a complementary on-line system to further characterize the type of contamination.

While some technologies such as on-line chemical characterization system, or decision support monitoring system can monitor the quality of drinking water in real-time and detect deviations using a proper algorithm and library of fingerprints, there are some other technologies such as spectral fluorescence laser technology, image processing technology, multi-angle light scattering laser technology, and rapid response tests for total micro-organisms and toxicity which can be used as complementary steps. However, reviewing the available technologies for real-time monitoring of contaminants and especially pathogens demonstrates there is no single instrument currently available for on-line monitoring of all potential contaminants. The most effective approach currently available is an early warning system, using on-line measurements of indirect indicators, and instigation of collection of a sample for more detailed analyses for confirmation of the event and trying to identify the type of contamination.

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