Demonstration of biological sulfate reduction in cold climate

Aim and goal

The aim of the project is to demonstrate a biological sulfate reduction process on low-temperature process water from Swedish mines and thereby reduce the water footprint of the mining industry.

Challenge

Upcoming legislation will limit the allowed amount of sulfate in process water being released from the Swedish mining industry. Large amounts of water are used to conduct mining operations and the mining industry therefore constantly strives to find new, efficient ways to both reduce the amount of sulfate but also reduce the water footprint from the process. So far, it has been difficult to use biological methods for sulfate reduction due to the cold climate prevailing in Swedish mines. The project's innovation has the potential to solve this problem.

Solution

The aim of SO4-BIORED is to offer an energy and resource efficient solution to reduce the water footprint from the Swedish mining industry. The goal is to demonstrate a sulfate-reducing bioprocess pilot plant (TRL 6) with a reduction efficiency of 95%. The process has previously been validated at laboratory scale (TRL 4). The process could potentially extract metals from residual streams, resulting in higher resource efficiency in the mining process. The main innovation in the project is the effective microbial culture that has the ability to reduce sulfate in the cold climate prevailing in Swedish mines. The product, hydrogen sulfide, can precipitate metal ions which form a concentrated and stable product (metal sulfides). The product can also be elemental sulfur which can be used as fertilizer or used for sulfuric acid production.

A fully automated mobile bioprocess pilot plant will be used to demonstrate the process at Boliden's mines. The main objective is to reduce the sulfate concentration down to 50 mg / L in residual streams while at the same time creating value through the generated metal sulfides and the elemental sulfur.

Effect

The effect of the project is to reduce the water footprint from the Swedish mining industry and reduce the amount of sulfate released. This is linked to the global sustainability goals 6 and 9: Clean water and sanitation for all and Sustainable industry, innovations and infrastructure.