Determining contamination source with hydraulic software packages

When a drinking water contamination incident occurs, it is very important to take action to localise the contamination source as fast as possible. However, this possibility was not present in the hydraulic software packages used by the water companies. Within the BTO’s Tailored Research programme, in a project for PWN and Brabant Water, KWR has investigated how to make this software capable of determining contamination sources.

Backtracing techniques

When one or several sensors in the drinking water network detect a contamination, it is very important to be able to pinpoint the location of the contamination source as fast as possible. To this end, KWR has developed a so-called ‘backtracing technique’ using substance transport models. By determining the path that the water has taken before passing a specific sensor, and combining the data for several sensors, one can determine where the contamination source is located in the network.

Application in practice

To make the backtracing technique applicable in water practice, it needs to be implemented in the hydraulic software packages used by the drinking water companies. The Dutch drinking water companies frequently use the Synergi and Infoworks software packages. Based on the manuals, and in consultation with the hydraulic experts at PWN and Brabant Water, an inventory was made of the ways in which the backtracing technique can be implemented in these packages. This is not only important in the context of determining contamination sources, but it also provides information about the best placement of the sensors in the network, with a view to maximising the amount of information they supply.

Graphic representation of the result of a backtrace in Synergi 4.8.0. The different colours of the water mains indicate the relative contribution of each path. In this example, the red main makes the biggest contribution to the water that flows past the ‘start’ joint (sensor).