We have identified and reviewed technologies for waterquality analysis of fecal-contamination indicators. Some established technologies used in microbiology laboratories (e.g., immunoassays or enzyme fluorescence) have the potential to be applied in on-line equipment if combined with automated detection methods and proper reduction of the
time of analysis. More recent technologies (e.g., PCR, FISH or electrochemiluminescence) enable the quantification of very low concentrations of bacteria with high specificity, but require a lot of sample processing and have not been applied to raw, on-line samples. Optical techniques have the advantages of being immediate and reagentless, so that, combined with capture methods, they may become the ideal detection technology for on-line water monitoring. However, it has been difficult to obtain successful results in real samples in a simple, reliable manner.
Identification of devices has been based on the previous technologies, mainly addressed to generate an alarm
when having an episode of accidental or deliberate fecal contamination. Detection of microorganisms at very low
concentrations or within a turbid, complex matrix is a challenging task, especially when aiming for on-line
monitoring.
All in all, although significant advances were made recently in technologies – and their applications – in monitoring water, we can envisage that, while many advances seem promising, they are not currently available and require further testing and/or development