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), P.O. Box 392, Florida 1710, South Africa
3. Research Centre for Carbon Solutions, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
4. School of Engineering, Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh EH9 3JL, United Kingdom