Water has become one of the most important issues of our time. Career prospects for those working in water and wastewater engineering are expanding, with over 90,000 workers in the water environment industry, and technological developments are rapidly advancing our understanding in this area. This accessible student textbook introduces the reader to the key concepts of water technology by explaining the fundamentals of hydrobiology, aquatic ecosystems, water treatment and supply and wastewater treatment. The Water Framework Directive is the driving force in European water management and protection, and Nick Gray uses this as the unifying theme in this new edition. This text provides a complete introduction to all aspects of managing the hydrological cycle and is ideal for those interested in a career in the water industry. For Masters students in environmental science, engineering and construction courses and those taking the CIWEM diploma, Water Technology is an essential resource they will find useful in their professional careers.