This book is proposed to be a collection of excellently peer-reviewed manuscripts from the 2025 16th International Conference on Environmental Science and Development (ICESD 2025), which was held successfully during June 6-8, 2025 in Xiamen, China. It aims to provide a unique platform for researchers, scientists, engineers and professionals from all over the world to present their latest research results and new ideas in terms of environmental science and development. We deeply appreciate their active participation in ICESD 2025. ICESD 2025 was organized by International Society for Environmental Information Sciences, co-organized by Xiamen Society for Environmental Sciences and United Nations Development Programme, hosted by Jimei University, China. This conference was supported by the National Key R&D Program of China (2023YFC3206503) and the Innovative Research Group of the National Natural Science Foundation of China (52221003). The conference received strong support from experts, practitioners and researchers from various countries. During the conference, our conference honorary chair, Prof. Gordon Huang from the University of Regina, Canada hosted the opening ceremony for the conference. Our conference chair, Prof. Chaotian Xie from Jimei University, China and Dr. Weidong Zhang from United Nations Development Programme were invited to give Opening Remarks for the conference. Prof. Huining Xiao from University of New Brunswisk, Canada, Prof. Guangwei Huang from Sophia University, Japan and Prof. Shin-Cheng YEH from National Taiwan Normal University provided wonderful keynote presentations. ICESD 2025 has received submissions contributed by researchers from many countries, such as China, Thailand, United States, Australia, Egypt, Malaysia and other countries. After two rounds of rigorous peer reviews, 47 papers were selected in this proceeding, within the scope of environmental science and development such as 1) Water Treatment and Quality Control: Technologies, Mechanisms, and Applications, 2) Watershed Hydrological Modeling and Water-Ecology-Energy-Food Nexus Management, and 3) Low-Carbon Technology and Carbon Management Innovation and others. We sincerely thank all the authors, the conference committee members, and the reviewers for their participation and support.