Polish coal mine recovers valuable resources from wastewater

Every year, Polish mines dump nearly 4 MT of salt into rivers and freshwater basins in the form of industrial wastewater. This salty wastewater (also known as brine) is putting great environmental pressure on Poland’s rivers.

The Zero Brine project is seeking to change this by recovering water, salts, magnesium and other minerals for reuse from coal mine wastewater, effectively ‘closing-the-loop’ on industrial wastewater from coal mining. On 8 October, press, government officials, and industrial and environmental experts visited the Bolesław Śmiały coal mine to see the ZERO BRINE technology making this happen, operated by the Silesian University of Technology (SUT).

The current technology standard used at Poland’s only industrial-scale desalination plant serves as the benchmark for the Zero Brine solution. This technology is energy intensive with limited results in salt recovery due to the inability to recover additional elements present in the feed stream. The proposed Zero Brine technology at Bolesław Śmiały aims to cut energy consumption in half while testing a combination of nanofiltration, reverse-osmosis, and electrodialysis for the recovery and reuse of all elements in the feed water, including demineralized water, salt, magnesium hydroxide – commonly used in refractory or heat resistant materials – and a calcium-rich solution that can be used as a deicing liquid. The remaining saline concentrate can be either sold or used for salt crystallization.

In operation since July 2019, the pilot plant can treat 400 L/h of wastewater and is showing promising results that could signal interest for the local industry with 18 active hard coal mines in operation around Poland. The business opportunities of Zero Brine are replicable to other industries worldwide. Because of how similar in composition coal mine wastewaters are to sea water, the proposed technology could also be applied in the desalination industry.

Three additional large-scale pilot plants have been developed in other process industries including a demineralized water plant in the Netherlands, a silica plant in Spain, and a textile factory in Turkey, providing the potential for immediate replication and uptake of the project results after its successful completion.