Water and wastewater treatment solutions provider WEC Projects, in conjunction with its partner, minerals processing equipment manufacturer Multotec, has designed and custom engineered a wastewater treatment plant for a gold mine in Mali.

The plant incorporates a modular design which simplified logistics while reducing transport and installation costs.

The mine operator is a client of Multotec, a specialist engineering company that approached WEC Projects to jointly develop a customised solution to remove arsenic from the mine’s wastewater.

A multistage removal system was required to meet the strict standards for the mine’s discharge.

However, the system also required a modular design that would facilitate the transportation, installation and commissioning of the plant.

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

From there it enters a two-stage chemical precipitation and 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 150 m3/h and is capable of reducing the arsenic levels from about 13 mg/ℓ to less than 0.1 mg/ℓ.

WEC Projects MD Wayne Taljaard explains that the project incorporates several unique features besides its modular design, including nine custom-designed, proprietary lamella clarifiers and a multistage arsenic removal process.

“The mining industry in Africa presents some very unique challenges, not least of which is the remote location of many of the mines,” says Taljaard.

He adds that this included the difficulties experienced in getting staff and equipment to sites where road, power and water infrastructure are often lacking.

“The Covid-19 pandemic [exacerbated these] difficulties for us and the client, causing delays that reduced the timeframes for delivery,” he says.

The contract was received in February 2020 and the plant was fully installed in May 2021, while WEC Projects completed the commissioning of its scope of work in July last year.

WEC Projects has completed several 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,” he concludes.