Quick picture of microbial water quality

Microbial water quality is an important element in determining the safety of water for humans, animals, plants and the environment. Today’s methods only conclude afterwards whether the water quality was poor. This explains why companies that depend on the availability of good water quality wish to have an early warning system. This would enable them to take timely action to counter a deteriorating microbial water quality, which could for instance impact public health or operational management.


Over the last few years various in-line sensors have been developed for the periodic assessment of the microbial biomass or growth potential in a water system. The sensors analyse the amount of bacterial cells, adenosine triphosphate (measure for active biomass), enzyme activity of bacteria, or the speed of biofilm formation. Since the sensors are deployed in-line and produce periodic results, they could potentially serve as early warning system.


The objective of this project is to develop a new service for the quality control of drinking water, process water and cooling water. This involves the following challenges:

  • researching which monitoring method (sensor) is most suited to which situation;
  • translating the monitoring results to specific water-quality problems;
  • setting the associated alarm or action values;
  • determining whether the deployment of a combination of different sensors offers added value;
  • investigating whether the sensors can predict a deterioration in the microbial water quality, or can indicate when this will cause problems.

In the project we also want to investigate the extent to which the sensors can be used for the detection of the most critical process in the causation of water-quality problems, so that management measures can be defined in a more targeted manner.

Anticipated solutions

We begin the project with a validation of different sensors against existing microbial parameters in the lab. At the same time, research is done into whether the sensors can be improved, and tests should indicate whether and how they can be applied to several water types. Tests will then be carried out at different drinking water utility and industry locations, to study the extent to which the sensors can predict water quality problems, and what the associated alarm or action values are. We also research whether the sensors can identify the most critical process. In cases where the sensors appear to provide a good early warning system, a protocol will be developed to use this approach in controlling microbial water quality at several locations.