The Optimum Water Reclamation Project is only the second plant of its kind in South Africa and is leading the way internationally in mine water treatment, says engineering and environmental consulting firm Golder Associates Africa.

Optimum Colliery, a wholly owned subsidiary of Optimum Coal, located in Pullen’s Hope, Mpumalanga, commissioned an initial review of the colliery’s overall mine water balance before the initiation of the project.

The review suggested that urgent measures were required to address the mine’s excess water intake, which was about 26- million litres a day from old underground and opencast mine workings.

The Optimum Water Reclamation Project proposed the construction of a mine water treatment plant and associated infrastruc- ture that would treat up to 15-million litres a day of this excess mine water to potable standards.

In addition to addressing the excess mine water problem, the project would also tackle the dire shortage of potable water in the Steve Tshwete local municipality. Both the Middelburg/Mhlazi and Hendrina/KwaZamakuhle areas within the municipal area have been facing curtailed water availability for some time.

The project allows for up to 30% of the potable water from the treatment plant to go to the Hendrina/KwaZamakuhle areas and the rest possibly to the Middelburg/ Mhlazi area in future.

Golder was the lead engineering, procurement and construction management (EPCM) service provider for the Optimum Water Reclamation Project.

As lead EPCM contractor, Golder was responsible for the overall engineering, procurement and construction management of mine water collection and treatment, reclaimed water storage and distribution, sludge and brine disposal and bulk electrical power supply.

Golder chose Aveng Group subsidiary Keyplan (Aveng Water) as the technology provider of choice, owing to its world-first high-recovery precipitation reverse osmosis (HiPRO) process.

“The HiPRO process is a world-first with a higher than 97% recovery rate that produces high-quality potable water from mine water that has high acidity and sulphate levels, compared with most membrane plants, which are designed for a recovery of between 70% and 85%,” says Golder’s Tiaan Bauman.

Golder was responsible for the design and construction of two 5.5-million-litre clean water storage reservoirs. Once the mine water has been fed through the HiPRO process, the desalinated water is stored in the clean water storage reservoirs for distribution to the municipal system.

The Optimum Water Reclamation Project has set a benchmark for mine water management and water reclamation in South Africa, states Bauman.

He adds that the self-sustaining project is not only economically viable but also of benefit to the greater community as a whole.

Golder was commended for the Optimum Water Reclamation Project at the 2011 Con- sulting Engineers South Africa Engineering Excellence Awards, which took place in August.