The appropriate type of treatment process is dependent upon site-specific factors such as:
Lime neutralisation is frequently used for many hard rock mines hosting sulphidic deposits susceptible to acid rock drainage. Lime neutralisation can vary from simple addition of slaked lime, to high Density Sludge (HDS) processes with sludge recirculation and use of clarifiers.
For situations where more stringent treatment is required, then treatment processes such as ultrafiltration and ion exchange may be required as primary and/or secondary and/or tertiary treatment stages.
Treatment processes may be active i.e. requiring significant power and chemical inputs (e.g. HDS,) or passive i.e. utilising naturally occurring physico-chemical processes (e.g. treatment wetlands).