Smart sewers

Waterboards, as the managers of wastewater treatment processes, are increasingly confronted with waste discharges of hazardous substances and chemicals into sewage water. Since the wastewater treatment plants (WWTPs) have not been designed to remove such (volumes) of hazardous waste from the stream, the result might be that it ends up in surface water and pollutes the receiving water system (a river for instance). This concerns a wide spectrum of hazardous substances, such as acids, lye and used motor oil.

The first damage they cause is to the biological treatment process in the regional WWTPs and the sewer network itself, the second is inflicted on the environment and public health. The discharge incidents force WWTP managers (waterboards, treatment boards) – and, ultimately, society – to incur huge extra costs for the temporary storage elsewhere of the wastewater, and for the restoration of the treatment plant’s operations.


A sensor and monitoring system provides insight into the frequency, extent and consequences of (direct) discharges into the sewer system. This project will test new sensors that can detect the presence of hazardous substances in real-time. This will make it possible to limit the damage to the sewer system, environment and public health at an early stage – for example, by closing the WWTP’s main basins in time.

The intended technology involves three elements:

  • placing (previously lab-tested) sensors,
  • sampling and analysis of sewage water using high-resolution mass spectrometry, and
  • advanced data processing techniques.


The research challenge will be to select the most suitable combination of sensors and determine their optimal placement in the sewer network. It is this that will actually make early signalling possible. Qualitative and quantitative data will be obtained about the composition of the sewage water contamination by means of advanced chemical analyses. This information is needed to guide the sensor measurements.


A sensor and monitoring system for hazardous substances that provides insight into the frequency, extent and consequences of the (direct) discharge of these substances into the sewer. It functions as an early-warning system to signal discharges. It enables the parties affected to take rapid action to limit and deal with the damages.