Emalahleni , Blueprint for Treatment of AMD

Monday 22nd June, 2009

Acid Mine drainage (AMD) are waters arising from gold, coal, uranium and platinum mine operations and is a major threat to the environment.

Aveng Water has developed a high recovery desalination process (HiPRO) which significantly outperforms any comparable technology. What sets this process apart from other technologies is its ultra high water recovery. Most RO membrane process can achieve no more than 75 to 80% water recovery. To improve on this, one normally uses an evaporator/ crystallisers. The HiPRO process eliminates the need for an evaporator which has a relatively high operating cost.

The project is a world first with both positive environmental and economic spin-offs.

The installation at Emalahleni consistently achieves greater than 97% water recovery while the end product is potable water. The waste brine stream made up of brine and solid waste products amount to less than 3.0% of the total feed flow. The solid waste products are saleable grades of calcium sulphate and less pure calcium sulphate and metal sulphates.

Since is start-up in September 2007, the plant has been operating at full capacity producing on spec potable water. Following the success start-up and operations, the plant capacity has been increased to meet the an ever increasing demand from both mining operations and Emalaheni Municipality. Future desalination capacity will be 50,000 m3/day when complete.

The project is a joint initiate between Anglo Coal and Ingwe Colliery, owned by BHP Billiton Energy Coal South Africa. Potable water resulting from the process, is supplied to the local Emalahleni Municipality to augment the existing water supply, making up a 20% of the total Municipal water demand.