World's First Underground Niobium Mine Achieves Zero Liquid Discharge with Q-SEP® Ultrafiltration Membranes

Challenge

The Niobec mine's wastewater contains high levels of total dissolved solids, often exceeding 25,000 ppm. The underground mining operations result in saline wastewater that contains high concentrations of sulfate, sodium, chloride, and heavy metals. The mine wastewater required complex pretreatment to comply with chloride and TDS discharge standards set to protect local waterways and ecosystems.

Traditional methods of softening the mine water before reverse osmosis (RO) and thermal treatment would have led to excessive chemical consumption and the generation of large quantities of sludge, posing disposal challenges and higher costs. Aquatech’s innovative outside-in ultrafiltration membrane technology was implemented to reduce chemical consumption and sludge generation while delivering a more sustainable, reliable, and cost-effective water management solution for the mine.

Solution

Aquatech employed a modularized water treatment system to treat the mine’s high-salinity water. The mine’s advanced pretreatment solution integrates media filtration, Q-SEP® PVDF outside-in UF treatment from QUA, Aquatech’s membrane subsidiary, and state-of-the-art reverse osmosis (RO) processes. The RO units use seawater reverse osmosis (SWRO) and ultra-high-pressure reverse osmosis (UHP-RO) to minimize brine flow to a downstream thermal evaporation system, which further concentrates the UHP-RO reject into a highly saline brine stream.

Once processed, the brine is sent to the site’s paste backfill plant to be mixed with their tailings and binder and eventually returned underground, creating a positive environmental cycle.

Result

Niobec’s facility demonstrated effective approaches to managing high-salinity water, cutting sludge production, and reusing industrial brine, offering a robust model for other underground mines worldwide. This water treatment system enabled the mine to proceed with its expansion while complying with effluent disposal limits.

In 2024, Niobec was named Water and Wastewater Project of the Year by the Engineers’ Society of Western Pennsylvania (ESWP). This prestigious recognition highlights the project’s engineering excellence and innovation in water treatment.

This project underscores a shared commitment by Niobec, Inc. and Aquatech to environmental stewardship and operational efficiency, paving the way for broader mining industry adoption of advanced water treatment solutions.