1. School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, P. R. China
2. Guangzhou Sewage Purification Co., Ltd., Guangzhou 510000, P. R. China
3. Guangzhou Urban Planning & Design Survey Research Institute, Guangzhou 510000, P. R. China
4. School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, P. R. China