This paper covers research results and construction techniques applied for marine outfall systems of three medium sized cities located on the coast of the Black Sea. The treatability and design data related to the pre-treatment and marine outfall system of a large pulp and paper mill on the same coast are presented. The preliminary studies and the development of the design criteria of the related marine outfall systems were carried out by the Department of Environmental Engineering of Istanbul Technical University. The scope of the project included oceanographic, hydrographic, and geotechnical surveys and water quality measurements. A construction method, which is widely applied in Turkey for laying of the glass reinforced pipes(GRP), has been evaluated. Pollution loads originated from the land based sources have been given and their probable environmental impacts in the receiving water body have been discussed.