Process Options for Phosphorus and Nitrogen Removal from Wastewater

The paper reviews the current capabilities of processes for phosphorus and nitrogen removal in relation to the EC urban waste water treatment Directive. The Directive is briefly described and the implications for the UK are discussed. This is followed by a review of biological and chemical processes for nutrient removal with special reference to their current state of application and performance. Particular attention is paid to processes for biological phosphorus removal which, in the past, was said to be less reliable than the chemical options but which is now being more widely applied in other parts of Europe as well as South Africa and North America. Processes for modifying both activated sludge and biological filter systems to meet the Directive are briefly described.