MINERAL PROCESSING PLANT, OMAN
A mineral processing facility in Oman required a new water treatment system to recover water from multiple effluents to improve environmental sustainability and reduce waste disposal costs.
The water treatment system was successfully completed in March 2022, with Westwood Water consulting in all phases of the project, including engineering design, installation, and commissioning to nameplate capacity.
High recovery water treatment is critical in the Middle East due to the scarcity of fresh water in the region. It was a design requirement that the mineral processing facility recover as much water as possible from the effluents to minimise the client’s fresh water usage.
During design, the effluents were analysed and found to contain a challenging variety of contaminants – acid, sulphates, hardness, heavy metals, arsenic, and sodium. Such a diverse effluent chemistry required careful process design to ensure the plant could produce high quality treated water without excessive equipment scaling or fouling.
A process flowsheet was developed using three main technologies – alkaline precipitation, ion exchange, and reverse osmosis (RO). The process was designed to recover 90% of the water for recycling back to the facility.
Figure 1: Water Treatment Plant Process Flowsheet
Using precipitation as the first treatment step enabled bulk removal of divalent contaminants (hardness, sulphate, heavy metals) and reduced the scaling potential for downstream technologies.
The subsequent ion exchange and reverse osmosis systems polished the water to a high quality and at high recovery. Most of the contaminants were precipitated into solids and dewatered using a filter press for low volume, low cost, disposal.
Since its completion, the effluent treatment plant has operated robustly at design capacity, significantly reducing the facility’s consumption of fresh water.
Westwood Water remains engaged with the client as a water treatment consultant for future projects.