Flow analysis system for climate adaptation of wastewater mains

Flow analysis system for climate adaptation of wastewater mainsBackgroundClimate change poses major challenges for the municipal wastewater pipes and the possibilities to manage and climate-adapt the distribution network after the expected increased number of torrential rains that will occur as the climate changes.

Measurement and analysis of the wastewater mains creates a better decision-making basis for investments.PurposeThe project aims to develop IoT connected ultrasound sensors for measuring flow volumes in the wastewater mains as well as cloud service with monitoring and analysis software.

Wastewater mains are not pressurized and usually only partially filled pipes and channels which cannot be measured with traditional water meters.

The proposed system enables effective monitoring of the wastewater lines and its function in the event of torrential rain.SolutionThe system is based on IoT connected ultrasound sensors that are installed in the wastewater mains as well as a monitoring and analysis part in the cloud. The flow volume sensors can measure waterflow speed and water depth via ultrasound.

The sensors are connected to a battery-powered local measuring unit that converts the measurement data.

By entering the area of the pipe or culvert in which the sensor is located in, a flow volume is continuously calculated.

That measurement data communicates via NB-IoT to the analysis and monitoring software in the cloud.The monitoring part of the software warns and alarms in real time.The analysis software allows you to follow afterwards how the water has moved during a downpour and how it has affected the system.CompetitorsThe existing systems on the market today are developed with older technology with local measurement storage that is physically emptied at the installation site.

They are usually installed temporarily in various locations that are desired to be analyzed. (see e.g. www.mjk.se and marketplace.sweco.se/produkt/vatten-energi-industri/flodesmatning-i-sjalvfallssystem/)Product developmentUltrasonic transducerThe sensor calculates the flow rate and water depth in real time and is connected via cable to the measuring unit.The ultrasound technology that is planned to be used to measure water flow is called Doppler technology and is based on frequency changes during movement.

The sensor sends an ultrasonic signal against the water flow. The signal will "bounce" on particles, sediment, air bubbles and is received by a receiving ultrasound sensor. The receiving ultrasonic sensor receives back a different frequency than the one sent out. By comparing the signals with each other, the water movement is calculated.

The ultrasound signals that the ultrasound receiver receives are very weak and without being able to analyze the measurement in the transducer itself, the measurement does not work as the signal deteriorates in the cable to the measuring unit.The water depth is calculated relatively easily using a pressure sensor.Measurement unitConverts the measurement data and communicates with the cloud service, the electronics are placed in an IP68 rated enclosure and powered by a rechargeable and replaceable battery.Communicates via NB-IoT band 20.

Band 20 is suitable in installations where the amount of data is low and where the transmitter unit is often placed underground.Has an internal local WiFi router where a PC can be connected locally to perform settings as needed.

The settings can e.g. be pipe dimensions, map coordinates, etc.The cloud serviceContains databases of the measurement data collected and which can be reported in various ways and exported.The monitoring part contains various settings for different types of warnings and alarms.The analyzes can be partly on individual sensors or on entire systems including maps where you can follow the effects of e.g. a downpour.The analyzes can be carried out in real time, but afterwards fast-forwarded to more easily see when and where risks and disruptions occur.