WEC Projects, a South African water and wastewater solutions provider, has designed and custom engineered a wastewater treatment plant for a gold mine in Mali to remove arsenic.

The plant incorporates a modular design which simplifies the logistics and reduces the costs of transport and installation, the company said.

In the treatment process, the mine's wastewater undergoes primary solid/water separation using coagulation and flocculation and the primary clarifier.

It enters two-stage chemical precipitation and a secondary clarification process to reduce the arsenic levels. The final stage sees the sludge undergo dewatering before disposal. The treated water, although not potable, is then reused by the mine for process applications.

The plant has a processing capacity of 150m3/hr and can reduce the arsenic levels from around 13mg per litre to less than 0.1mg per litre.

Neither the customer nor details of the mine have been disclosed. 

Wayne Taljaard, managing director of WEC Projects, said the mining industry in Africa presents some "unique challenges," specifically that many mines are in remote locations and difficult to service with staff and equipment.

"The project incorporates several unique features in addition to its modular design, including nine custom-designed, proprietary lamella clarifiers and a multi-stage arsenic removal process capable of treating the wastewater to the mine's discharge standards," Taljaard said.

"WEC Projects has completed a number of water and wastewater treatment projects throughout Africa.

"Our ability to provide a customised and modular solution for Multotec underscores our ability as a major player in the industry both in South Africa as well as across the continent."

In September 2021, WEC Projects unveiled the final designs of water processing plants for the potash-producing Culluli Mine, Eritrea.