Wastewater sensor will detect pollutants and identify polluters

11-09-2019
wastewater treatment,sensor

Wastewater treatment is a difficult task.  And even with large industries taking note of their responsibility in the disposal of polluted and hazardous waste in water streams, some other manufacturing companies still refuse to acknowledge this responsibility.

Researchers from the Fraunhofer Institutes for Integrated Circuits IIS and for Reliability and Microintegration IZM in Germany have recently developed a sensor system that could potentially help battle polluters.  Of course, the system is designed to primarily detect pollutants in the water, but it is also designed to identify if a certain company complies with environmental laws.

The device consists of two sensors as Fraunhofer IIS group manager Dr Matthias Völker described in the Fraunhofer website press release.  "The sensor system is designed to detect certain substances that are typically found in affected wastewater," he said.  "It comprises two sensor components - physical sensors and a chemical sensor - as well as an energy management system, a control and communication system and a sampling system."

The system starts its work when a robot places three pieces of rings in the sewage pipe.  One of the rings is placed in front of the influent stream of the manufacturing company and a second ring is placed directly behind the first one.  These first two rings are equipped with sensors that would take physical properties like temperature, pH, and conductivity of the stream.  Wireless communication system enables the two rings to compare the measurements they took.  A third ring is then placed further back in the sewage canal and records chemical properties of the water.  It is installed with a sampling system that is activated after the second ring transmits a signal to control a micropump to collect a few microliters of the wastewater that is later on diluted before allowing to come in contact with the chemical sensor.

The chemical sensor is composed of six different electrodes, each with polymeric coating, layered so that the gaps between each layer are perfectly sized to accumulate specific pollutants.  The pollutants then affect the reading of the chemical sensors, indicating the presence of certain pollutants in the sample.

The device is also equipped with a sampler that would collect an amount of wastewater that can be analysed in the laboratory for the assessment and confirmation of a trained and qualified analyst, before malpractice in the manufacturing company causes them to go to court.

Aside from this, a flushing system uses a cleaning solution to detach any entrained pollutant molecules from the electrodes, so that the sensors may be reused.

To look at the reliability of the system, the researchers tested its individual components in laboratories of project partners, then later with real wastewater in an artificial wastewater system, and then afterwards in a real sewage pipeline.  Researchers from Fraunhofer IZM are now planning to conduct large scale pilot with partners in Europe.