1. Water Treatment Group, Water Research Centre, Frankland Road, Blagrove, Swindon, SN5 8YF, UK
2. Linhoff-March Limited, Targeting House, Gadbrook Park, Northwich, Cheshire, CW9 7UZ UK
3. Professor of Environmental Engineering, Department of Civil Engineering, Imperial College of Science and Technology, Imperial College Road, London, SW7 2BU, UK