Water and wastewater engineering is the world's biggest industry with more professionals working in it than in any other single industry sector. 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. In 2000, the Water Framework Directive came into force this is the most substantial piece of EC water legislation to date. It requires all inland and coastal waters to reach good status by 2015. Professor Gray includes the new framework throughout this new edition taking into account the implications of compliance and practice, as well as discussing the topical issue of sustainable principles in water management. It covers water quality and regulation. It deals with water quality assessment, management and treatment. It includes a new chapter on sustainability within water technology.