Observator Instruments has supplied an advanced monitoring station to drinking water company Dunea. The monitoring station is being used to monitor water quality in the Vliet between Leidschendam and Voorschoten, the Netherlands. The installation is part of Dunea’s ‘Drinking Water for the Future’ programme, which aims to make water from the Vliet suitable for the production of drinking water.

Until now, water quality in this area was determined through periodic sampling and laboratory analyses. To gain better insight into rapid fluctuations in water quality, Dunea opted for a permanent monitoring system.

The monitoring system supplied by Observator Instruments consists of a robust monitoring pole with integrated sensors, data logging, communication and an autonomous power supply. The system has been specifically designed for long-term field deployment.

Sensor technology
By combining different sensors, Dunea obtains real-time insight into the direction and speed of the water flow, water quality and the level of contamination. Observator Instruments specialises in supplying high-quality monitoring systems, including systems for water quality and flow measurements. These include:

• A Sontek SL1500-G3 ADCP flow meter for measuring flow direction and flow velocity. The instrument also features an absolute pressure sensor (for measuring depth) and a temperature sensor.
• An EXO2S multiparameter probe for measuring, among other parameters:
  • pH
  • conductivity
  • turbidity
  • dissolved oxygen
  • algae and chlorophyll
• An S::CAN spectro::lyser for water quality measurements such as:
  • turbidity
  • UV
  • temperature
  • nitrate (NO₃)
  • Dissolved Organic Carbon (DOC) and Total Organic Carbon (TOC)
  • Biological Oxygen Demand (BOD)

Smart data technology and power supply
At the heart of the system is the OMC-048 data logger developed by Observator Instruments. The logger has an integrated modem and controls all connected sensors and their cleaning wipers. Measurement, transmission and cleaning intervals can be configured flexibly according to the monitoring requirements.

In addition to collecting and transmitting measurement data, the logger also monitors the status of the system itself. This includes continuously recording the internal temperature, humidity and supply voltage. Monitoring the supply voltage is particularly important for checking the performance of the batteries and solar panels.

The power supply for Dunea’s monitoring installation is fully autonomous and consists of solar panels combined with batteries. This allows the system to remain permanently operational without an external power supply.

Future-proof drinking water production
By continuously monitoring both the water quality and the flow dynamics of the Vliet, Dunea can better assess what is required to make this water source suitable for drinking water production after 2030. Permanent online monitoring makes it possible to detect changes in water quality immediately and to accurately analyse trends over longer periods. The monitoring system therefore provides valuable information for water management, risk analysis and the further development of sustainable water abstraction and treatment strategies within the ‘Drinking Water for the Future’ programme.