Ex-Situ Groundwater Bioremediation

The Challenge

A national power utility operating a coal-fired power station in Mpumalanga faced persistent acid mine drainage and elevated sulphate concentrations from an adjacent colliery. Conventional chemical treatment carried prohibitive long-term costs and generated large chemical sludge volumes. The utility required a sustainable, biologically driven alternative capable of operating at scale with minimal chemical input – and needed pilot-scale proof before committing to a full facility.

Our Approach

iWater designed and deployed a containerised biological sulphate reduction (BSR) pilot plant, progressing from scoping through to full operational demonstration over 10 months.

• Comprehensive site scoping and water characterisation to define feed chemistry and design parameters
• Custom bioreactor system with PLC-controlled dosing, mixing tanks, and integrated monitoring
• Phased installation with iterative refinements based on operational feedback and performance data
• 9 technical deliverables from scoping through to upscale design, with international engineering review
• Safe decommissioning with bacterial communities preserved in bioreactors for future re-activation
• Deliverable: 5 000 / day of treated acid mine drainage (AMD) water to release quality set out in water use license (WUL) after gabion and wetland polishing system

The Results

The pilot plant successfully demonstrated biological sulphate reduction under real site conditions, generating validated data to support full-scale facility design.