Department Urban Water Management

Development of a non-contact measurement sensor to monitor the wastewater quality in sewers as a part of the Co-UDlabs project

Gobal problematic in the sewer systems

Our urban sanitations systems are based on a sewer networks that leads the effluents to the treatment plants. Although the water characteristics are well measured in the treatment plant, the collection of data from the sewer infrastructures is still limited to water flow and level. A better monitoring of the water quality in the sewer can provide essential information to improve the management of the sanitation systems.  This is especially relevant during raining events, because they often cause the wastewater treatment plant to be overwhelmed with the quantity of effluents to treat, which leads to the release of polluted waters in the environment.

These issues are one of the main focus of the European Co-UDlabs project. An urgent need for improvement in our sewer systems has been identified, and the development of new sensors to monitor the network is part of the research objective (WP6). The project mentions the need for “a transition from current inefficient approach” and “more robust, autonomous and interconnected smart monitoring techniques, and digital water data analysis tools”.

Wastewater measurement devices

To measure wastewater parameters like contaminants concentrations, the conventional methods involves the immersion of sensors or the collection of samples. In both case, the contact with the effluents is necessary. That leads to issues such as deterioration of the sensors or clogging. The sensors need regular inspection and maintenance, and therefore have to be accessible, which explains why it is so hard to collect data from sewer. However, non-contact sensors like radars and ultrasonic devices have been developed to address these issues, and already allow to measure water velocity and water level in sewer with minimal maintenance need

Research project: development of a non-contact sensor to monitor sewer parameter such as COD and turbidity

During a 4 years PhD, a new type of sensor will be developed. It will consist in a lamp that lights the surface of the sewer water and a detector that captures the reflected light in the form of a spectrum. This method of measurement is based on similar principles as spectrophotometry: the composition of the water have an influence on the reflection of light at his surface. Spectrophotometry is already widely used to analyze wastewater, especially through the measurement of light absorption, but the analysis of reflection spectrums is quite recent in the field of wastewater analysis.

Thanks to this innovating method, parameters from sewer can be monitored from the distance and without any contact with the wastewaters. However, this technology is still in its first development. To this days, this setup has only been tested in laboratory with artificial effluents placed in a recipient. This configuration is very far to sewer, where the effluents are in movement and have a complex and variable composition. The aim of this PhD will therefore be primarily to face the issues of implementing this system in a much more complex environment. A big part of the project is also to develop efficient algorithm to analyze the measured spectrums. This PhD will take place under the supervision of Dr. Jörg Rieckermann and in cooperation with the Co-UDlabs project.


Pierre Lechevallier PhD Student Tel. +41 58 765 6476 Send Mail
Dr. Jörg Rieckermann Group Leader Tel. +41 58 765 5397 Send Mail


4 years, starting on August 2021

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