Appendix A: Stakeholder list

Annexure E: Summary of Brine Treatment Technology options

BRINE TREATMENT TECHNOLOGIES

Different brine management strategies are used in industry, these are grouped as brine minimization processes, product recovery processes and final disposal processes. In this section 16 brine treatment methods are summarised (Van der Merwe et al, 2009).

EVAPORATION PONDS

Evaporation ponds are the most popular treatment option for brine wastes. It works well for small brine volumes and is easy to construct and operate. The evaporation process depends on the size of the pond due to the role it plays in the evaporation rate. The salinity of the waste is also important because it has a negative impact on the evaporation rate (Dama-Fakir, n.d.).
The evaporation from the ponds is driven by solar energy (Kepke, n.d.). The salt concentration in the brine is increased when the water is evaporated from it. This method was used for centuries to recover salt from the ocean (Van der Merwe et al, 2009).
When the evaporation occurs under natural conditions, large evaporation ponds are required. This can be overcome when wet surfaces (capillaries or clothes) are exposed to the wind. The surface density will be high enough to generate an evaporation flow with minimum energy consumption (Arnal, 2005).
The evaporation ponds can either be lined or unlined ponds, depending on the geographic detail of the area (Van der Merwe et al, 2009). The only mechanical equipment, and therefore additional energy, that is required for the evaporation ponds is feed pumps (Van der Merwe et al, 2009). The rest of the process relies on heat generated from the sun. This process is not recommended when the weather conditions are generally cold and/or wet, i.e. where the evaporation rates are low, or when the disposal rate is much higher that the evaporation rates (Van der Merwe et al, 2009).