1. Research Student, School of Water Sciences, Cranfield Univ., Cranfield, Bedfordshire, England MK43 0AL.
2. Process Engineer, Severn Trent Water Ltd., Avon House, St. Martins Rd., Coventry. England CV3 6PR.
3. Process Engineer, Severn Trent Water Ltd., Avon House, St. Martins Rd., Coventry, England CV3 6PR.
4. Senior Lecturer, School of Water Sciences, Cranfield Univ., Cranfield, Bedfordshire, England MK43 0AL.