1. Magalies Water, Scientific Services, Research & Development Division, Erf 3475, Stoffberg Street, Brits 0250, South Africa
2. Department of Environmental Sciences, College of Agriculture and Environmental Sciences, University of South Africa (UNISA), Florida 1710, South Africa
3. Council for Scientific and Industrial Research (CSIR), Smart Places, Water Centre, Pretoria 0001, South Africa
4. Research Centre for Carbon Solutions, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK