Archive news article

Ikona BIP Ikona Portal Pracownika Ikona poczty Facebook Twitter Instagram Youtube Linkedin RSS Ikona szukania PLEN

Poland's only mine water desalination system

At Jastrzębska Spółka Węglowa, the discharge of saline water is handled by Przedsiębiorstwo Gospodarki Wodnej i Rekultywacji (Water Management and Reclamation Company). The main components are the Olza retention and feeding system and the Desalination Plant in Czerwionka-Leszczyny. A study visit was made to the latter.

photos: Joanna Karwot, Dawid Lach

The Desalination Plant in Czerwionka-Leszczyny collects mine water from the Budryk mine, which is released from the rock mass during mining operations. This prevents the discharge of highly saline waters into surrounding rivers, and in the process, high-quality evaporated salt is produced. In 2022, salt production volume was about 67,000 tons. The salt produced by the plant has obtained certification as food-grade salt admitted to marketing, issued by the National Institute of Hygiene and the State Sanitary Inspector.

- This type of installation, which produces table salt from mine water, is a unique installation, the only one in Poland and probably in Europe. And this is what sets us apart, in addition to the high quality of this salt - says Krzysztof Baradziej, President of the PGWiR Management Board. - However, the main purpose of this activity is to desalinate mine water thanks to which less salt is discharged into rivers thus contributing to broadly defined environmental protection - adds Krzysztof Baradziej.

Each year, “Dębieńsko” treats nearly 1.5 million cubic meters of saline water, producing high-quality food-grade salt from it. It has a crystalline purity of 99.4% NaCl, so it meets quality parameters that are difficult for other manufacturers to achieve. It also has many elements that are valuable for health, such as magnesium. The plant has a quality control systems thanks to which the “Dębieńska Salt” meets high standards, sanctioned by certificates and permits required in the food industry.

- First, the brines are purified in a multi-stage filtration process. The brine is then concentrated using reverse osmosis filters, crystallization takes place and later the salt is centrifuged and dried to the appropriate parameters - explains Dariusz Leśnik, Director of Salt Production at PGWiR.

In the case of the Knurów-Szczygłowice mine, drainage is carried out on the basis of a water rights permit and consists in pumping saline mine waters to settling tanks on the surface, where they undergo a mechanical cleaning process. Part of the pumped-out saline mine water (up to a dozen percent) is used in underground technological processes. Unused water from draining the mine is discharged into surface waters in the catchment area of the Odra River (Bierawka River, Czarnawka stream, Książenicki stream) in an environmentally safe manner, in accordance with the conditions set forth in the applicable regulations and the water rights permits held.

The remaining mines of Jastrzębska Spółka Węglowa - on the basis of permits issued by competent institutions - the State Water Management Company (Państwowe Gospodarstwo Wodne Wody Polskie) - feed saline waters into the “Olza collector” dosing system, and then they enter the Odra River in a controlled manner. The saline waters are discharged into the river through nozzles located in the bottom of the Odra bed, allowing the waters to be mixed along a short stretch of the river. The salinity of the Odra River is controlled through a monitoring station in Krzyżanowice. The retention and dosing functions based on precise and constant monitoring make it possible to reduce the maximum salt concentrations in the Odra River by 60 percent below the limit values. The Olza collector retention system has retention basins that allow water discharge to be halted for about 20 days.

It must be emphasized that due to the need to ensure the safety of the crew and the mine property, the mine's drainage system must be kept in constant operation. There is no way to stop the discharge of saline mine water. Mine water is pumped to the surface by pre-constructed systems and must be discharged into watercourses on an ongoing basis for safety reasons. The Knurów-Szczygłowice mine does not have facilities that could take over retention functions. Efforts are underway to adapt the existing sedimentation tanks for use as sedimentation tanks and retention basins.

The photos show pressurized collector pipes of the steam heating system feeding the heat exchanger. The overheated steam supplied to the exchanger causes the brine flowing through the exchanger to heat up, evaporating the water and thus concentrating the brine.
BC1 evaporation system.
After passing through the salt crystallizer and evaporation system. The excess hydrated fraction is returned to the salt crystalliser, while the salt pulp is gravity-directed to the rotating equipment (salt centrifuge dryers), where the salt grains are finally separated from the liquid.
Concentration cone - the salt pulp with precipitated salt crystals is directed to the concentration cone, where the initial separation of the liquid and solid phases occurs.
The salt centrifuge dryer is intended for centrifugation, i.e., separation of (wet) salt grains from brine.
The brine is separated from the salt grains using sieves that are placed on the centrifuge dryer drum.
With regard to reverse osmosis (RO) systems, the so-called stacks are used to concentrate moderately saline brines to chloride concentrations high enough to allow the brines to be fed into the thermal concentration system.
Desalinated water - the permeate can be used for a variety of purposes, including machine cooling system feed, plant technology, and even pipeline service water. In addition, the piping system allows the permeate to be directed towards KWK Budryk as a source of industrial water for mine use.
AC Compressor SC-40 - our largest steam compressor. It is used to inject steam from the crystalliser sump into heat exchangers for brine concentration.
Fluid bed dryer. The finished product, i.e., salt after centrifugation, is still a wet product. The salt grains are dried on specially profiled sieves by a hot air jet. The hot air not only dries the salt grains, but also directs the salt to the co-packaging room via conveyor belts.
Palletising robot - it is used to stack bags on pallets in a fully automated manner. It definitely simplifies the work.
"Sól Dębieńska" meets high standards, sanctioned by the certificates and permits necessary in the food industry.