History was made in South Africa in January with the launch of a locally developed, first-of-its-kind solution to treat acid mine water drainage.
Called the Rhodes BioSURE Process®, it was hailed as the most cost-effective biological treatment option currently known in the world aimed at reducing sulphates in acid-rich mine water without the external addition of chemicals.
The solution was developed by Rhodes University’s environmental biotechnology group over the past eight years, with the support of the Water Research Commission, the East Rand Water Care Company (ERWAT) and BioPAD.
It removes sulphate from acid-rich mine water, using primary sewage sludge, a by-product from ERWAT. Together, the two waste products ensure improved water quality.
The new solution was launched in Ekurhuleni on January 18, near the Blesbokspruit Ramsar site in Springs. The solution will be applied to extraneous mine water discharged by Grootvlei Proprietary Mines into the Blesbokspruit Ramsar site.
Besides improving the water quality discharged into the wetland, the solution will ensure safe and stable biosolids are produced.
In terms of the international Ramsar Convention, the Blesbokspruit site was placed on the Montreux Record in 1996 because the ecological character of this wetland was threatened as a result of pollution from extraneous mine water. Underground mine de-watering is required to gain safe access to gold deposits in the East Rand Mining Basin, while securing some 4 000 jobs.
Praising the new product, Minister of Water Affairs and Forestry Buyelwa Sonjica said at the launch that mining resources in South Africa must be developed in an environmentally responsible manner.
‘Although the problem of acid mine drainage production and treatment relate to most of the country’s gold and coal mines, the issue has become thorny in recent years, with the decline and closure of the Witwatersrand gold mines,” said the minister. ‘Defunct mines in the area are filling up and consequently decant increasingly large volumes of low-grade saline and heavy metal-polluted water.
‘This water finds its way into the Vaal river system of the East Rand basin, and this water now has to drive economic growth there. The problem will become worse and will last for many decades, and even for centuries, if we do not find innovative solutions to address it.”
The production of saline and acid water is a natural consequence of mining activities where the excavation of mineral deposits below the natural groundwater level exposes sulphur-containing compounds to oxygen and water. There is also a problem where surface waters run over exposed ore seams and elicit similar chemical mechanisms and acid formation.
This acid and saline water causes problems as the vast majority of natural life is designed to live and survive with water that is at, or near, neutral and not acid. The drainage acidifies the local watercourses and so either kills or limits the growth of the ecology.
Effects are even more pronounced on vertebrate life such as fish than on plant and unicellular life. The net effect is that the health of the environment is affected significantly.
Research efforts directed at sorting out the acid mine drainage problem by the mining industry over the years have dealt with treatment strategies focusing on both the physico-chemical and biological processes. The most conventional methods involve chemical precipitation processes and membrane filtration.
But these treatment processes tend to be expensive, as they require skilled operators and installation and maintenance to ensure the sustainability of the system. Most may not be economically viable and sustainable for developing countries.
Minister Sonjica hailed the Rhodes BioSURE Process® for offering a low-cost, sustainable technology that is ‘proudly South African”, that is user and environmentally friendly, and is suitable to the local conditions.
According to Martin Schermers, the MD of Petrex, the holding company of Grootvlei Mine, the new solution is a step towards treating the total volume of water discharged and to restoring the ecological character of the Blesbokspruit river, so as to remove the Blesbokspruit wetland from the Montreux Record.
‘It is an innovative and cost-effective tool to improve the quality of mine water, not just in South Africa, but all over the world. Grootvlei Mine is proud to be part of pioneering a sustainable, locally developed solution for mine water treatment, which proved to be problematical in the past.
‘The implementation of sustainable mine water treatment projects is the real challenge in the long term,” Schermers said.
Pat Twala, ERWAT’s MD, pointed out that the solution is significantly cheaper than any other alternative, reducing costs from about R5/kl to approximately R1/kl. ‘The technology has been fully developed and a demonstration plant is operational, with results indicating performance comparable to the best alternative technology,” he said.
ERWAT provides bulk waste water conveyance and treatment for a host of industries, as well as more than 3,5-million people who have access to sanitation services.
Twala highlighted the benefits of the Rhodes BioSURE Process®:
– It removes heavy metals and radioactive elements
– It breaks down aromatic pollutants
– It destroys pathogens
– It provides an unusually robust biotechnological solution
– The waste output is a safe humus compost material
– It can be customised to suit any requirements
– It has low capital and operational costs
– It has the lowest cost solution for acid mine drainage.
SIGNPOST
The Rhodes BioSURE Process® is a joint programme of the Water Research Commission, BioPAD, ERWAT and the Environmental Biotechnology Research Unit at Rhodes University. Companies interested in the process should contact Koos Wilken at ERWAT, (011) 929-7003 or [email protected]; or Martin Schermers at Grootvlei Mine, (011) 362-6395 or [email protected].