Task

A city in Germany was repeatedly confronted with illegal discharges into the public sewerage system.

Although the possible polluters could be narrowed down based on the substances identified, there was no clear evidence to transfer the resulting costs to them.

For this reason, a system was sought that would be able to monitor all discharges from a particular discharger on an event-driven basis by taking samples.

The real challenge was not the sampling itself, but the reliable detection of a discharge. This proved to be difficult as no measuring devices could or should be installed directly in the sewer and all equipment in the sewer had to be explosion-proof.

Our solution

In another project, we continuously measured whether water was actually being drawn in while the sample was being drawn in to ensure that water and not just air was actually being drawn in.

The idea was to reverse” this technique. We developed a trigger system that uses a simple suction hose to recognise whether water is being introduced. The suction end of the hose is simply fixed at the desired trigger level without the need for any further installations.

Function

The device monitors at short intervals, for example every minute, whether a discharge is taking place. As soon as water is detected, the device automatically starts the pre-set sampling programme. At the same time, a notification is sent via SMS, for example, so that the operator can react immediately if necessary.