由于人类活动致使自然水体的富营养化,使水质恶化,造成鱼类和其他水生生物大量死亡。富营养化的防治是水污染处理中最为复杂和困难的问题。营养物质去除的高难度,至今还没有任何单一的生物学、化学和物理措施能够彻底去除废水的氮、磷营养物质。介绍了当前水体中磷、氮的控制标准和污水脱氮除磷(生化硝化、反硝化、生物除磷等)技术；同时适当选择了几例德国污水和地表水处理的典型工程实例。

The human activity causing eutrophication,and worsening the water quality,has resulted in a great number of death of fish and aquatic animals and hydrophytes.The prevention and cure of eutrophication are the most complex and difficult problems in the water treatment.Because of the difficulty of treatment,so far there has been no measure to eliminate the nourishment like nitrogen and phosphorus in grain by single measure of biological,chemical or physical treatment.The control standard of nitrogen and phosphorus in the current water,technique of denitrogenation and dephosphorization (techniques of biological nitrification,denitrification,biological dephosphorization etc.) in sewage are introduced.Several typical project instances of surface water and sewage treatment in Germany are enumerated.