1. Bioresource Engineering Research Group (BioERG), Department of Chemical Engineering, Faculty of Engineering and the Built Environment, Cape Peninsula University of Technology, P.O. Box 1906, Bellville 7535, South Africa
2. Academic Support Programme for Engineering (ASPECT) & Water Research Group, Department of Civil Engineering, University of Cape Town, Rondebosch, Cape Town 7700, South Africa
3. Bioresource Engineering Research Group (BioERG), Faculty of Applied Science, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa
4. Centre of Excellence in Carbon Based Fuels, School of Chemical and Mineral Engineering, North West University, Private Bag X1290, Potchefstroom 2520, South Africa