1. Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
2. MOE Key Laboratory of Theoretical Chemistry of Environment, School of Chemistry and Environment, South China Normal University, China
3. Department of Biotechnology, Delft University of Technology, Julianalaan 67, NL-2628 BC Delft, The Netherlands and KWR Watercycle Research Institute, The Netherlands