A kind of filter device of denitrification of what is closed in this creation system,System is equipped with a water space capacity,For accommodating water； One transfer pipeline is equipped with an input terminal and an at least output end； One denitrification filter element system is connected with the output end of the transfer pipeline,System sets into there is a filter material in the denitrification filter element,It is that culture has a denitrifying bacterium on the filter material； One unary system of drawing water is connected with the input terminal of the transfer pipeline,The unary system of drawing water is drawn water end equipped with one,The water extracted in the water space capacity is used,It is transported in the denitrification filter element； Water flow is set to pass through the filter material in the denitrification filter element,And the nitrate in water can be contacted sufficiently with the denitrifying bacterium on the filter material,It uses and generates a denitrification.本創作係關於一種反硝化作用之過濾裝置，係設有一容水空間，以供容納有水；一輸送管路設有一輸入端及至少一輸出端；一反硝化過濾單元係與該輸送管路之輸出端相連通，該反硝化過濾單元內係設入有一濾材，該濾材上係培養有一反硝化菌；一抽水單元係與該輸送管路之輸入端相連通，該抽水單元係設有一抽水端，藉以抽取該容水空間內的水，將其輸送至該反硝化過濾單元內；使水流經過該反硝化過濾單元內的濾材，而水中的硝酸鹽能充分與該濾材上的反硝化菌接觸，藉以產生一反硝化作用。
