Purification system for disposal of polluted or waste water using water plants

A water-plants water treatment system for purifying the waste water which has been treated by a conventional biological treatment system, comprising:

• a distribution section for temporarily storing the incoming waste water from the conventional biological treatment system;
• a first section having a filtration layer and water caltrops in the upper part of said filtration layer to filter the first treated water from the distribution section and to remove nitrogen and phosphorus components;
• a second section having water hyacinths planted therein, to purify the water coming from the first section;
• a third section having great duckweeds planted on the water surface thereof, for purifying the water coming from the second section and for vaporizing the nitrogen gas into the external atmosphere based on the de-nitrogenizing reaction method;
• and
• a fourth section having a filtering layer disposed therein and additional water caltrops in the upper part of said filtering layer to filter the water from the third section and to remove nitrogen and phosphorus components.