1. School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai200240, P. R. China
2. Chongqing Research Institute of Shanghai Jiao Tong University, No. 168 Liangjiang Road, Chongqing401120, P. R. China
3. Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, 3001Leuven, Belgium
4. Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001Leuven, Belgium