In publicity the importance of regarded phosphor in waste water cleaning is discussed very controverse and one-sided. On this reason the publication of environmental questions is an instrument of the management in connection with the installation of the environment monitoring system "oko-audit＇: To much or to less phosphor could cause disturbances in pipe system or clarification plant As a result the expenses of water treatment increase. This paper shall be a help and an argumentation material for chemists concerned with environmental questions.