Novel Clay-Based Adsorbents for Mine Water and Groundwater Remediation, 2013-2016
Dr Wilson M Gitari
Department of Ecology and Resources Management, School of Environmental Sciences, University of Venda
Visitors to the University of Venda (UniVen), situated close to the centre of the town of Thohoyandou in the north of Limpopo, will be struck by the distinctive red tones to the campus. That, it turns out, is in part due to the high clay content of the ground in the region. From his labs on the campus, Dr Wilson Gitari is trying to put these natural resources to good use. His project, which is the first at UniVen to be funded by THRIP, aims to harness this clay to clean up contaminated groundwater. The major components of the clay are smectite minerals, so called because they undergo reversible expansion when they absorb water.
Groundwater studies have shown that it is the most widely used source of drinking water in Sub-Saharan Africa, especially in rural scattered communities. But in parts of Limpopo and other provinces, groundwater has particularly high concentration of fluoride. While, typically, this mineral is useful in the prevention of dental cavities (which is why it’s used in toothpaste and can be found in tap water), too much fluoride has been associated with a condition known as dental fluorosis, in which the protective tooth enamel slowly deteriorates. Dr Gitari and his group want to see if the clay soils and bentonite can be used to extract excess fluoride from groundwater by manipulating the clay’s chemical make-up. The plan is to incorporate the modified clay into a series of water treatment devices that are both cost-effective and easy to use, keeping the needs and circumstances of rural households in mind.
There could also be larger-scale industrial applications of the clay. Dr Gitari and his group are collaborating with colleagues from the University of the Western Cape and Wits University on a project targeting the treatment of wastewater from coal mines and power stations. In such scenarios, bentonite clay will be integrated with modified coal fly ash – a powdery waste from coal-fired power stations that colleagues elsewhere are introducing into certain nanotechnologies – to remove elements such as sulphuric acid, and to restore the pH balance (the balance of alkalinity and acidity) of wastewater.
Assisting Students and Human Resource Development
Currently the project involves a total of eight students – two doctoral students, four busy with their master’s (three are female), and two in their honours levels. Their contributions have produced important dissertations, conference publications and a number of journal papers. These outputs were only possible because of the THRIP funding.
Project Impact on the
There are a number of pottery projects, employing women from the area, being run in the communities surrounding UniVen. Dr Gitari envisions his project providing further development opportunities for these communities. Once the ceramic filter prototypes are optimised and designed, there is potential for small-scale industrial production in water defluoridation, creating valuable jobs and imparting skills in the community. The women could, for example, be trained to produce the clay filters – and the complete treatment devices – using locally available clay soils.
Benefits to the Environment
Aside from its socioeconomic impact, the devices that Dr Gitari has in mind hold clear-cut environmental benefits. This includes the increased provision of clean, safe drinking water, as well as the protection and remediation of the environment. The role that this could play in the clean-up of acid mine drainage holds immense potential for South Africa.
Growing Research Capacity
The THRIP grant has opened new funding opportunities for the university. In this case, it has allowed Dr Gitari to leverage funding to the tune of R150,000 per ye
ar for three years from ESKOM. In addition, the group was able to bring the Water Research Commission on as a funding partner, the research body committing itself to a grant of R690,000 over three years (2014-2016). These awards have been invested in student support and the purchase of small equipment and consumables, such as the outsourced analysis of samples. (That said, Dr Gitari would like to see modified THRIP funding ratios – say 1:1 – for rural institutions such UniVen).
§ Number of students: 8
§ Number of female students: 2
§ Number of black students: 8
§ Number of researchers: 3
§ Number of black researchers: 2
§ Number of female researchers: 1
§ Number of publications: 7