- CASE STUDY
Supply of a Sewage Treatment Plant at Lucara Diamond’s Karowe Mine
Project Information
Client
Lucara Diamond’s Karowe Mine
Location
Letlhakane, Botswana
Capability
Industry
Capacity
150 m3/d
Requirements
- Expansion of mine’s current sewage treatment plant capacity from 100 m3/d to 150 m3/d
- Utilisation of natural treatment process to polish the final treated effluent quality
- Conservation of water to meet Government requirements
Top Challenges
Water Scarcity
Water is scarce in the eastern Kalahari Basin region where the mine is located.
High Temperatures
Operating temperatures in the region average around 35°C.
Strict Government Mandates
The Botswana Government mandated strict water saving protocols for the mining industry.
Requirements
- Expansion of mine’s current sewage treatment plant capacity from 100 m3/d to 150 m3/d
- Utilisation of natural treatment process to polish the final treated effluent quality
- Conservation of water to meet Government requirements
The Result
- Installing a Model A conventional activated sludge (CAS) plant adjacent to the existing sewage treatment plant effectively treats the additional influent sewage flow.
- An artificial wetland not only acts as a final polishing step but also creates a habitat for various sensitive fauna and flora.
- The treated water produced is reused for irrigation and dust suppression, reducing the overall water consumption of the mine.
“
This is a unique feature for a mine as usually such artificially wetlands are built for much larger installations such as municipal sewage treatment. The Government’s mandate for water conservation forced companies in Botswana to apply creative thinking to overcome the challenge of operating in an arid country. The solution offers a number of advantages as the effluent is relatively odourless and the system is flexible enough to cope with fluctuations in input. It requires little maintenance and ensures that the mine remains within the constructs of the law.
Wayne Taljaard, Managing Director of WEC Water
Wayne Taljaard, Managing Director of WEC Water
”
How WEC Added Value
To create the artificial wetland, a shallow dam was built, its bottom was filled with gravel, and reeds were planted. The treated water from the treatment plant feeds into the wetland area where nature is left to take its course.
Extended
Aeration
The WEC sewage treatment plant supplied features an extended aeration system using conventional activated sludge to treat domestic sewage.
Natural
Treatment
Natural organisms and a filtration process of the final polishing phase of the artificial wetland remove heavy metals and nutrients.
Water
Recycling
The expanded plant provides a source of water that can be recycled for use in dust suppression and irrigation.
Water Processing Size Highlight
The sewage treatment plant was upgraded from 100m3/day to 150m3/day to accommodate an increase in the number of staff.
Water and Wastewater
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