Online technology for operational monitoring of drinking water treatment (TRINKcontrol)

Case study on the use of different online systems

Online measurement technology in drinking water treatment

Efficient online monitoring is becoming increasingly important in drinking water treatment. New applications include automatic process control and online microbiological measurement systems.

Surveillance of chemical-physical parameters such as pH value and turbidity with online technology are state of the art for monitoring drinking water treatment. On the other hand, there is a great demand for microbiological online analysis methods. However, only very few measuring principles seem feasible, yet practical experience is often lacking.

The aim of the DVGW research project TRINKcontrol is to determine experiences with online measured variables and to evaluate them with regard to the possibilities for further process control. Online-suitable microbiological analysis methods are to be tested in practical use. These are flow cytometry, which allows quantification of the total cell count of the water, and methods that record microbial activity by measuring enzyme activity or adenosine triphosphate (ATP), the universal energy carrier of all biological cells.

There is potential for further use of online measurement technology for optimised process control, for example, for flocculation or inline and direct filtration. Here, measured values for raw and clear water turbidity often serve as control variables for adjusting the flocculants dose. In most cases, the operating personnel control the processes manually with the help of the measured data based on long time operating experiences. Automatic process control is not yet common.