Physical, chemical and biological process techniques and tools for pollution prevention and sustainability: an introduction.

This special issue contains 17 articles that are disseminating the physical, chemical and biological process techniques and tools for pollution prevention and sustainability. They are selected from the presentations made at the 12 th annual international conference on "Challenges in Environmental Science and Engineering", CESE-2019 that was held in Kaohsiung, Taiwan, from the 3 rd to 7 th of November 2019. There were 181 delegates from 18 countries and regions who participated in CESE-2019. The conference covered 8 themes, namely (i) the Application of Membrane Technology & Nano-Technology;