Dr. Zhao Youcai is professor of environmental engineering at School of Environmental Science and Engineering, Tongji University. He received his bachelor's degree from Sichuan University in 1984 and Ph.D. from Institute of Chemical Metallurgy (now Institute of Process Engineering), Chinese Academy of Sciences, Beijing in 1989). He has worked at Aristotle University, Greece, National University of Singapore, Tulane University, USA, and Paul Scherrer Institute, Switzerland as a research fellow or visiting professor. He has authored or co-authored 138 publications published in peer-reviewed internationally recognized journals, 420 publications in Chinese journals, and authored or co-authored 75 books (as an author or chief editor). Currently, his research interests include treatment of municipal solid wastes, sewage sludge, hazardous wastes, polluted construction wastes and industrial wastes. Dr. Zhang Chenglong is professor of environmental engineering at Shanghaicollaborative innovation centre for WEEE recycling, Shanghai Polytechnic University. He received his bachelor's degree from Wuhan University in 1996, masters degree from National Engineering Research Center of Waste Resource Recovery in 2003 and Ph.D. from East China University of Science and Technology in 2008. He has authored or co-authored 69 publications published in peer-reviewed journals, and authored or co-authored 5 books. Currently, his research interests include cleaner production and treatment of WEEE, industrial wastes and hazardous wastes.