Compared to other world cities, the municipality of Vienna invested in the sustainable protection of its spring waters at a very early stage. Spectrometer probes from s::can GmbH have been used since 2001. Today 70 systems continuously monitor the water quality in real-time.
Most of the drinking water for Vienna’s 1.9 million inhabitants is supplied from several mountain springs located in the Lower Austrian-Styrian Alps more than 100 km away from the city. In general, the water from these springs is of very high quality. Yet because they lie in geological regions consisting of karstic formations, natural events such as very heavy rainfalls can cause rapid fluctuations of raw water quality, especially in turbidity, but also elevated concentrations of dissolved organic substances can occur. Furthermore, anthropogenic events like accidents in neighboring areas of the springs might affect the quality of the raw water.
The raw water from the springs becomes drinking water after transport by gravity over two support lines (HQI and HQII). So to ensure excellent water quality, early warning and event detection is crucial at all times. Before 2001, the main springs and important positions in the main pipes were monitored with cabinet analyzers. Those needed separate housing, consisting of power supply, pipe installations and special foundations to be built. Due to the high costs of this and the remote location of the springs the setup of a broader monitoring network covering all essential springs was nearly impossible.
In 2001 twelve s::can spectrometer probes were operated simultaneously to the existing cabinet analyzers as a test run. In total readings of more than 18 months were analyzed, which proofed the measuring performance and long-term stability of the spectrometer probes. The parameters measured include Turbidity, UV254, UVT, Nitrate, TOC, DOC, spectral fingerprint, Temperature and Conductivity.
Over the years additional systems were installed and today 60 spectrometer probes are in operation. Additionally, 10 nano::stations with i::scans were installed in front of UV disinfection facilities located at smaller springs. s::can is providing 24/7 maintenance assistance to Vienna Water Works formalized by a yearly maintenance framework agreement.
The s::can systems provide continuous 24-hour monitoring of the raw water. In the case of an abnormal event, like for example elevated turbidity levels after heavy rain falls, the water is simply discharged into one of the rivers flowing from the mountains and not used for drinking water production. Because the spectrometer probes require virtually no regular maintenance they can be operated in remote locations with limited access and the operating costs are very low.