Following the successful expansion of the sewage treatment plant at the Lucara Diamond’s Karowe Mine in Botswana, WEC Projects has secured further orders from the client for the design and construction of a sedimentation trap, a tanker filling station and associated infrastructure
The mine is located in the eastern Kalahari Basin, where temperatures average at 35°C, meaning water is a scarce commodity in the area, so much so that the government of Botswana has imposed severe water restrictions on companies operating within the region. WEC Projects originally designed and built artificial wetlands which the mine uses to treat its effluent, removing contaminants such as BOD, ammonia, suspended solids and heavy metals, to be reused as process water.
The new sedimentation trap will be used in the mine’s drilling operations as a water recycling process. The effluent is pumped from the underground drilling areas to a concrete trap and clarification unit, where it is dosed with alum and polymers to enhance the settling of the solids. The effluent overflows from the trap to the plant’s oil skimmer to remove floating oil.
The system can treat an average of 34 cu/m of effluent per day, but can be expanded up to 150 cu/mif required. The polished water is drawn from the tanker station and disinfected by dosing chlorine. Although the water is not suitable for human consummation, it can be reused in applications such as dust suppression.
WEC Projects contracts manager, Ruan Kellerman, said, “This project is a fairly standard one for WEC Projects, expect for the wetlands section which was certainly the largest of its kind we have undertaken. Our clients, many of whom are located in some of the driest and hottest areas of Africa where water is scarce, rely on us to come up with agile solutions for water reuse.”