The main source of drinking water for the city of Zurich comes from the lake. The water is pumped, filtered and purified several times before being injected into the network. Quality measurements are continuously carried out by various equipment. In addition, fish placed in an aquarium react to pollution. The equipment is very sensitive and can detect the slightest trace of pollution. However, they are not yet as fast as fish. Indeed, observing the behaviour of fish makes it possible to detect a water quality problem before measuring equipment. A camera system analyzes the behaviour of the fish and automatically triggers an alarm if problems arise. The measuring equipment then verifies the origin of the change in behaviour.

Fish are not only sensitive to pollution but also to too much nitrogen dissolved in the water. This is not harmful to humans but because it induces a change in fish behaviour, the camera system will then signal that this is a water quality problem. For this reason, the City of Zurich has decided to install our TDGP - Total Dissolved Gas Pressure - measuring continuously the concentration of dissolved gases (mainly nitrogen) in water.

The TDGP measurement system is directly interfaced with the pumping station management system.