Water is essential to our planet’s life, and protecting our water resources is a prerequisite for building a sustainable future. Since water use is inextricably linked to energy use, however, we face significant challenges. Water plays an essential role in many, if not most, manufacturing facilities. In a world facing a water-scarcity crisis, much research and development currently focuses on decreasing industries’ water-use footprint. This compendium volume looks briefly at several select industries and investigates various water treatment processes for each, including microbial biotechnologies, ozone-related processes, adsorption, and photochemical reactions, among others. The various industries are organized into four groups: Industries that produce petrochemicals Metal industries The semi-conductor industry The paper and pulp industries Collected by a well-respected expert in the field, the studies gathered here are intended to be a starting point for further investigation by graduate students and other scientific researchers. Today's research, found in these chapters, can be expanded to create tomorrow's even wider frame of study.