Water and wastewater engineering is one of the world's biggest and most interdisciplinary industries, employing chemists, microbiologists, botanists, zoologists as well as engineers, computer specialists and a range of different management professionals. This accessible student textbook provides a broad overview of the sector, introducing the reader to the key concepts of water technology by explaining the fundamentals of hydrobiology, aquatic ecosystems, water 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. Professor Gray uses the Water Framework Directive as the unifying theme of 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. . Covers water quality and regulation . Deals with water quality assessment, management and treatment . Includes a new chapter on sustainability within water technology. Read more... Basic considerations in hydrobiology -- Water resources and demand -- Factors determining the distribution of animals and plants in freshwaters -- Basic aquatic ecosystems -- Micro-organisms and pollution control -- Water pollution -- Water basin management -- Water quality and regulation -- Water quality assessment -- Water treatment and distribution -- Drinking water contamination -- Pathogens and their removal -- Nature of wastewater -- Introduction to wastewater treatment -- Biological aspects of secondary sewage treatment -- Fixed-film systems -- Activated sludge -- Other biological treatment systems -- Anaerobic treatment -- Physio-chemical treatment processes -- Sludge treatment and disposal -- Household and small-scale treatment systems -- Sustainability principles in water management