The nutrient limits imposed by the EEC directives are significantly more stringent than the effluent standards currently implemented in almost all European countries. Several biological processes are available for nitrogen removal. For phosphorus removal biological or chemical treatment options may be envisaged. The paper provides a critical review of the administrative and technological bases of nutrient management. The eutrophied state of the Marmara Sea is summarized to illustrate the need for nutrient removal in Istanbul and the technologies adopted.