Mining facilities have an ongoing groundwater pollution issue resulting from the seepage of the mine0s
tailing facility, waste dumps and natural conditions. Given the complicated water quality issues and
the need to maximize the volume of extracted groundwater for re-injection into the aquifer, a study
was performed to evaluate the application of reverse osmosis (RO) for contaminated groundwater treatment.
Due to high concentrations of calcium and silica in the contaminated groundwater, the feed water
recovery of the RO process was restricted to less than 60%. To enhance feed water recovery, a primary RO
followed by intermediate concentrate treatment and a secondary RO process was evaluated. For intermediate
concentrate treatment, electrocoagulation was compared to chemical softening. Chemical softening
and electrocoagulation were both effective in reducing the concentration of calcium and silica by more
than 90% in the primary RO concentrate. Electrocoagulation was more efficient than chemical softening
in the removal of metals, specifically mercury and selenium. With intermediate treatment of the primary
RO concentrate in combination with a secondary RO process, up to 90% overall feed water recovery was
achievable. The approach presented in this study can be utilized for efficient treatment of contaminated
groundwater at industrial facilities with minimal concentrate discharge