Drinking water is the most important intake of all. Its treatment requires costly processes. To oxidise and disinfect drinking water in the course of treatment, adding ozone is the best option. Because of its high reactivity, ozone must be produced and added on site under strict safety regulations. VEGA’s pressure transmitters make an important contribution to allow continuous treatment and obtain top quality drinking water.
The water supply system in this region is one of the largest and most traditional in Germany. Around 250 municipalities are supplied with about 90 million cubic meters of drinking water each year. The main priorities of the company in charge of the regional water supply are ensuring top quality and the security of the supply. When the 19th century came to an end and the 20th century began, the population in the Neckar region grew rapidly as industrialisation progressed. An extraordinarily far-sighted plan at the time was to bring drinking water with a pipeline from the Donautal (Danube valley) in Ulm, via the Remstal valley to the residential city of Stuttgart. This laid the foundation for the regional water supply system.
Ozone generators that guarantee the production of drinking water. VEGA Grieshaber KG
Plants to treat river water consist of a raw water pump which draws the water directly from the river, a pressure pipe from the pumping station to the waterworks and the treatment facilities. When the demand peaks, up to 2,300 litres of river water per second can be processed into drinking water. The injection of highly active oxygen (ozone) for oxidation and disinfection during drinking water treatment represents state-of-the-art technology. Ozone oxidises dissolved organic matter and kills or inactivates existing microorganisms. Ozone is formed when some form of energy decomposes molecular oxygen (O2) into individual oxygen atoms (O), which then react with molecular oxygen (O2) to form ozone (O3). This can occur through UV radiation, lightning strikes and also high-voltage electrical discharges. Due to its high reactivity, ozone is produced, transported and added to the water on site and in compliance with strict safety regulations.
The actual production process takes place in pressurized reactors, where electrical energy is applied to convert oxygen into ozone. Then, the resulting gas mixture flows into an ozone collecting pipe. The maximum ozone concentration is about 180 g/Nm³ at an operating pressure of 1.3 bar.
Measuring point with VEGABAR 82 and "Second Line of Defense" © VEGA Grieshaber KG.
Injectors feed the ozone into the water, while mixers distribute the tiny ozone bubbles evenly throughout the water volume. The water remains for a few minutes in large containers while oxidation and disinfection take place. To ensure that pressure measurement in the ozone collection pipe and at other important measuring points is absolutely safe and reliable, the VEGABAR 82 pressure transmitter with a ceramic CERTEC® measuring cell is used, as well as a second line of defence. This is an additional process separation by means of a gas-tight feedthrough above the process connection. Although the measuring cell is permanently resistant to ozone, the second line of defence provides an extra layer of protection against the leakage of ozone from the pipeline through the pressure transmitter.
The VEGABAR 82 thus plays an important role in safe ozone generation as well as in the continuous production of top quality drinking water.