1. School of Energy and Environment, Anhui University of Technology, Maanshan 243002, China
2. Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education, Anhui University of Technology, Maanshan 243032, China
3. Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtäle 2, 70569 Stuttgart, Germany