Evoqua United States - Canada - EN

Ensure High-Quality Drinking Water from Different Sources

National Water Supply Association replaces existing equipment with the help of Evoqua to continue their hundred plus year tradition of providing drinking water


The National Water Supply Association Baden-Württemberg is one of the largest and oldest long-distance water suppliers in Germany. The company was founded in 1912, the first installations went into operation in 1917. Today, the National Water Supply Association is responsible for the reliable and safe drinking water supply of about 250 cities and towns with an annual output of around 90 million cubic meters of drinking water of the highest quality. The National Water Supply Association obtains water for the drinking water supply from three different sources:

  • Groundwater from the Donauried area
  • Spring water from the Buchbrunnen spring of the waterworks Egau and river water from the Danube

The karst spring, the Buchbrunnen spring, in the Egau Valley in Dischingen, is used by the waterworks Egau for the drinking water supply. The karst spring water is naturally of a very high quality. The delivery of the Buchbrunnen spring is between 600 and 1,400 litres per second. After a treatment using two-layer sand filters, an upstream oxidation stage with ozone and downstream activated carbon filtration, the drinking water is disinfected for reasons of safety.

Chlorine dioxide is added to ensure the highest quality of drinking water in the extensive distribution network. The existing chlorine dioxide preparation systems were to be replaced after 20 years. Since the operators have had very good experiences with Wallace & Tiernan® products, systems of the same manufacturer were to be installed.


As a replacement for the previous chlorine dioxide equipment, the operators chose the DIOX-C professional system based on chlorine gas principle. Two systems were installed in the waterworks Egau (2010 and 2011), and one each in 2011, 2012 and 2013 in the Amstetten, Schönbühl and Osterbuch tanks. The National Water Supply Association was already assisted by the Günzburg specialists during the planning phase.

The geographical proximity promoted fast and easy exchange of information. The wishes of the operators for the storage of chlorine dioxide were taken into account in the implementation of the new systems. The associated chlorine gas supply was revamped, the same applies to the storage of the starting material of sodium chlorite, the solution dosing as well as the piping of the entire system.



The existing control system was renewed in all objects. At the request of the National Water Supply Association, the control is now integrated in a process control system.