The International Gothenburg Symposia on Chemical Treatment have proven to be a unique platform for the exchange of ideas between theory and practice. They bring together administrators, engineers and scientists, who are concerned with water purification and wastewater treatment through precipitation, coagulation and subsequent solid/liquid separation. This volume contains the proceedings of the 3rd Symposium, focussing on Pretreatment. Pretreatment is understood as the scene total of all measures taken at the pollutant source to protect water supply, the sewerage system, the central treatment plant, and the aqueous environment. It is, where applicable, the most efficient measure in ecological and economic respects. The contributions of this third volume address questions of surveillance, automation and remote control of installations as well as the principles of legal, administrative and economic measures for regulations within the context of pretreatment. Special attention is given to the possibilities and limits of pretreatment of industrial discharges. Again it is the editors'privilege to acknowledge the invaluable help from the authors of this book. It is the editors' hope that they might convey the significance and potential of pretreatment in water supply, in industrial waste management and in municipal wastewater treatment and sludge handling.