- CASE STUDY
Sewage Treatment Plant for Mothae Diamond Mine
Project Information
Client
Mothae Mine
Location
Maluti Mountains, Lesotho
Capability
Industry
Capacity
80 m3/d
Requirement
Domestic sewage from the mine camp requires treatment before being safely discharged into the environment.
Top Challenges
Increased OPEX:
The mine utilised honeysuckers to transport 60 m3 of waste per day to a sewage treatment works located 130 kilometres away, resulting in additional operational expenditure.
The mine utilised honeysuckers to transport 60 m3 of waste per day to a sewage treatment works located 130 kilometres away, resulting in additional operational expenditure.
High FOGs:
High Fats, Oil and Grease (FOGs) levels present in the feedwater adversely affects the biological treatment process.
High Fats, Oil and Grease (FOGs) levels present in the feedwater adversely affects the biological treatment process.
Low ambient temperatures:
The mine experiences low ambient temperature during the winter months due to its high altitude. The low temperature of the incoming feedwater slows down the microbial activities in the reactor.
The mine experiences low ambient temperature during the winter months due to its high altitude. The low temperature of the incoming feedwater slows down the microbial activities in the reactor.
The Result
- A conventional activated sludge (CAS) sewage treatment plant is installed at Mothae Mine to treat domestic wastewater to DWS general discharge limits. The automatic screen installed upfront of the CAS plant removes the debris, grit and grease from the feedwater to prevent poor performance of the biological process.
- The CAS plant is installed inside a building to ensure the incoming feedwater is at the desired operating temperature of 20 °C.
- An upfront fat and oil removal system was installed inside a building at the Mine.
“
The mine lacked a sustainable and cost-effective sewage treatment solution. Producing 60 m3 of domestic waste per day, Mothae Mine utilised honeysuckers to dispose the sewage at the nearest wastewater treatment works, located almost 130 kilometres away. WEC proposed the installation of its Model B CAS packaged treatment plant with a daily treatment capacity of 80 m3. The treatment technology allows for future upgrading as the mine operations expands by adding additional modules.
Marie-Louise Nel, Sales Manager for WEC Water
Marie-Louise Nel, Sales Manager for WEC Water
”
How WEC Added Value
Cost reduction
The new wastewater treatment plant eliminated the need for offsite treatment, resulting in an operational cost saving for the mine.
Accommodating low winter temperatures without affecting the biological process
The enclosed facility for the CAS plant maintains a minimum ambient feedwater temperature of 20°C to ensure the required biological activity in the reactor.
From The Client
We worked closely with WEC Water on-site to develop a sustainable solution. WEC Water had previously installed a sewage treatment plant at the neighbouring Letseng Mine and it was that facility that encouraged us to approach them. It was critical to complete the civil works, installation and commissioning of the plant during the winter season with the harsh climate posing many challenges.
Thato Tsephe, Project Foreman at Mothae Mine
Thato Tsephe, Project Foreman at Mothae Mine
Water and Wastewater
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