1. Bioresource Engineering Research Group (BioERG), Department of Chemical Engineering, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa
2. Centre of Excellence for Carbon-Based Fuels, School of Chemical and Minerals Engineering, North West University, P.O. Box 1290, Potchefstroom 2520, South Africa
3. Academic Support Programme for Engineering in Cape Town (ASPECT) & Water Research Group, Department of Civil Engineering, University of Cape Town, Rondebosch, Cape Town 7700, South Africa