Kromdraai water treatment plant follows success of eMalahleni

Friday 4th May, 2012

Kromdraai water treatment plant follows success of eMalahleni

By: Leandi Kolver
4th May 2012

Amodular mine water treatment plant developed by Aveng Water, a subsidiary of infrastructure group Aveng, is being installed at coal-mining major Anglo American Thermal Coal’s Kromdraai opencast mine, following the company’s success at the miner’s eMalahleni water reclamation plant (EWRP).

While the long-term plan is to treat water from Kromdraai at the EWRP, a short-term solution is required at the mine’s South Block operation while the capacity of the EWRP is being increased.

“The water is typical acid mine drainage (AMD), containing high levels of dissolved heavy metals and sulphates with low alkalinity,” says Aveng Water process and technology GM Martin Pryor.

The plant is currently being commissioned to treat 5 000 m3/d.

A contract to increase the capacity of the EWRP to treat up to 50 000 m3/d of mine water was awarded to Aveng Water in 2011. The plant not only produces water that is safe for environmental release but also converts the bulk of its product into high-quality drinking water while maintaining the highest safety standards.

The plant expansion is due for commissioning in 2013.

The plant, originally designed to treat 20 000 m3/d in 2007, was debottlenecked and upgraded in two interim phases to treat 30 000 m3/d since June 2011, says Pryor.

Aveng Water says it has the only commercial-scale AMD treatment solution with a total installed AMD water treatment capacity of 45 000 m3/d with greater than 99% water recovery. This technology is based on Aveng Water’s high-recovery precipitation reverse-osmosis (HiPRO) process.

The HiPRO process has been proven on a large scale to operate consistently, says Pryor, and has unique features such as the ability to produce drinking water that complies with the South African National Standard (Sans) for drinking water.

The process is also able to provide a zero liquid discharge (zero brine) solution depending on the feed-water quality, eliminating the need for high-cost evaporation and crystalliser plants. Parallel research and development, under the leadership of Anglo American Thermal Coal, has demonstrated that solid waste generation can be eliminated through the production of useful by-products.

The company also designed, built and operates Optimum Coal’s mine water reclamation plant, near Hendrina, in Mpumalanga, which has been operating since August 2011. This plant treats 15 000 m3/d of water. Aveng Water was awarded a three-year contract to design and construct the plant and to operate the mine water treatment plant after its commissioning in 2011.

Pryor adds: “Aveng Water has been in the water treatment business for the last 21 years and has concluded successful contracts with many of South Africa’s blue chip companies, including State-owned power utility Eskom, petrochemicals giant Sasol, the South African Nuclear Energy Corporation, and miners Acelor Mittal, Anglo American Thermal Coal, Impala Platinum, Goldfields, Areva, BHP Billiton Energy Coal South Africa and Paladin.”

Importance of Treating AMD

Untreated AMD is an environmental problem that has been well documented, but also presents a unique opportunity, if treated, to supplement constrained water demand in South Africa.

“The poor water quality in Mpumalanga makes it difficult to achieve the Sans Class 1 drinking water standard without employing advanced water treatment technology like the Aveng HiPRO process,” says Pryor.

The HiPRO process can also be tailored to treat AMD from the large number of ownerless defunct mines in the province.

Water treatment companies like Aveng Water are specially positioned to provide cost-effective and sustainable water treatment solutions to meet the environmental discharge water-quality requirements set by the Department of Water Affairs, concludes Pryor.

Edited by: Tracy Hancock

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