Water treatment

The minewater rising in the abandoned workings of the already shut down Mining Plant No. 1 is uranium-contaminated. To prevent it from entering the drinking water catchment area, contaminated water has to be pumped out continuously. Subsequently, the nearly 0.5 million m³ water contaminated with uranium is treated at the Minewater Treatment Plant.

The groundwater that is contaminated with inorganic salts in the vicinity of the tailings ponds (because of the above mentioned seepage) is extracted and treated at the Chemical Water Treatment Plant. 450,000 m³ of contaminated water is treated annually using slaked lime, which reduces the TDS (total dissolved solids) of the water. The generated gypsum waste has been disposed of in the waste storage area.


   

Acidic mine water - containing cadmium, lead and zinc, as well as other metals - comes to the surface from the former mine cavities in the Gyöngyösoroszi site. To remove the heavy metals from it, mine water is treated at the minewater treatment plant. The water treatment sludge has been deposited in the tailings pond in Bence-völgy in the past few decades.

As neither the design, nor the environmental and technical reliability of the pond was in compliance with safety requirements and environmental legislation, the disposal of tailings in the pond was terminated. This has become possible by the development of a water treatment technology which reduces the quantity of sludge by dewatering it in a centrifuge. Sludge with a higher dry content is deposited directly in ex-site hazard waste repositories where the sludge from the former sludge disposal area has been hauled, too. The former sludge storage area will be remediated in a few years' time.



Some of the uranium-contaminated seepage from the main waste rock pile enters the groundwater leaving the area and flowing into the direction of the drinking water aquifer. Due to the favourable hydrogeological situation, it has become possible to reduce the uranium content in the groundwater with a permeable reactive barrier. This is a passive water treatment technology, which makes it possible to treat contaminated waters in-situ.

The uranium-contaminated water passes through the permeable reactive barrier (PRB) containing a reactive iron precipitating the uranium in the barrier. The figures show the building of an experimental PRB, which is used for investigating the in-situ treatment of the uranium-contaminated groundwater. The work was carried out in the framework of the EU-funded PEREBAR project.

Integrated water management system:

After uranium mining was terminated, an integrated water management system was developed for the collection of contaminated and treated waters. The system guarantees that the discharge into Pécsi-víz meets all discharge limits specified in the Environmental Permit.

As a result of the reconstruction between 2000-2002, water coming from various facilities can be collected so that proper treatment can be carried out. After collection the water is treated at the appropriate treatment plants. Once treatment is complete, the water is discharged into the surface water receiver.