Non contact flow monitoring at Wastewater treatment plant

Wastewater treatment plants play an important role in every community. They ensure the sewage produced by homes, businesses and industrial facilities does not pollute the environment. However, if their ability to measure wastewater flow is compromised it can cause significant and long-lasting damage.

The community of Sonnen in Germany was experiencing such an issue. There were numerous problems with the community’s existing measurement instrumentation that prevented it from maintaining an accurate effluent flow signal from the waste water of Sonnen/Niederneureuth into the adjacent Sewage Plant of Hauzenberg. The facility needed to find a more reliable way of monitoring flow in order to make certain they were complying with strict environmental regulations.


Due to high flow velocity (2m/s), debris and fouling of sensor, the existing area velocity flow meter provided unreliable data. The most cost-effective solution was to replace the existing area velocity flow meter with a new a non-contact solution.

Detectronic GmbH’s confined spaces field team installed an ORAKEL non-contact Flow Monitoring System. The radar system is designed so it can be mounted in either direction making installation simple. The existing 30m cable stretching from the manhole (sensor) to the cabinet with mains power could be re-used. This meant only a new, IP68 rated water proof connection box was needed to connect the sensor cable with the existing cable to the cabinet.

The ORAKEL Non Contact flow meter can be installed anywhere with a clear, uninterrupted view of the water. It uses microwave technology to transmit short pulses that reflect off a moving surface back to the sensor which are analysed to determine the velocity.


Because of the non-contact measurement, the sensor cannot be harmed by sediments and floating debris, resulting in the new flow monitoring system providing reliable flow measurement. The ORAKEL records flow rates and volumes at 10 minute intervals and sends them directly to the treatment plant operators.




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