The use of the inline bacterial sensors BACMON and BACTcontrol to measure the bacterial water quality

The online microbiological sensors BACTcontrol and BACMON are new, rapid, online methods to determine total bacteria numbers or activity. These methods might be suitable for the online monitoring of any microbial disturbances in different water types and/or of the effect of control measures on water quality. However, before they can be reliably implemented, supplementary experimental research is needed. The aim of this TKI project was to validate both sensors under laboratory conditions, test their performance at several full-scale locations and compare the result with each other as well as with other parameters that were determined at these full-scale locations.
The validation of the BACMON and the BACTcontrol under laboratory conditions were done with dilution series of different water types. The results from this validation showed that in general the BACMON data correlated well with ATP and the bacterial cell numbers determined with flow cytometry or microscopy. Despite the good correlation between the bacterial numbers measured with the BACMON sensor, flow cytometry and microscopy, the bacterial numbers obtained with the BACMON were 1 to 2 log units lower than bacterial numbers obtained with the other two methods. The same result was observed with the water types tested under full-scale conditions. The BACTcontrol data from the dilution series of a surface water sample showed good correlations with the other biomass or cell number data, but such correlations were not observed for the dilution series of other water types.