The Ronneburg Operations Office supervises the water treatment plants (WTP) at the Ronneburg, Seelingstädt and Helmsdorf sites. The Ronneburg WTP will treat mine water discharge emerging from flooded mines located south of the A 4 motorway. These mine waters are typically characterised by acid pH and high levels of heavy metals (in particular iron, nickel, zinc). In contrast to the situation at other WTPs run by Wismut, radioactive components are of lesser importance. The flood water is anticipated to emerge in the Gessental valley where it will be collected and pumped to the Ronneburg WTP. Water discharge in the Gessen valley was predicted and occurred in 2005 with the flood water catchment system going into operation and the water treatment plant going on line.

In its present condition, the plant has a capacity to treat ca. 450 cubic metres of contaminated mine water per hour. For the purposes of controlled flooding, the plant capacity will have to be upgraded to 750 m³/h by the year 2010.

It is anticipated that the plant will be in operation for up to 25 years.

The Seelingstädt WPT treats waters from the inactive Culmitzsch and Trünzig tailings management areas. This includes residual supernatant water from the Culmitzsch site as well as seepage collected from the surroundings of both sites. Waters to be treated are weakly basic. Principal contaminants to be removed include uranium, radium, and to some extent arsenic. Treatment residues are immobilised by cement addition before disposal at engineered sites of the Culmitzsch tailings management area. Treated waters are eventually discharged into the Culmitzsch receiving stream. Design capacity of the WTP is 300 m³/h. The anticipated period of operation is in the order of 20 years.

The Helmsdorf WTP treats waters from the tailings management area of the same name. These waters include residual pond water and collected seepage. Plant feed waters are weakly basic and are characterised by relatively high levels of arsenic and uranium. Radium is also selectively removed. Water treatment residues are immobilised by addition of ashes and cement before disposal at engineered sites of the Helmsdorf tailings management area. Treated waters are directly discharged into the Zwickauer Mulde river. Design throughput of the WTP is 230 m³/h. It is anticipated that water at the Helmsdorf site will have to be treated for about 10 years to come.