1. Water Treatment Research, Inc., 2291 Plantation CourtLawrenceville, GA 30044, USA Tel.: (770) 488-4202 Fax: (770) 488-4253 james_amburgey@hotmail.com
2. School of Chemical Engineering, University of KwaZulu-Natal, Durban, South Africa brouckaertb@ukzn.ac.za