PROBLEM TO BE SOLVED: To provide a method for removing nitrate-nitrogen, capable of denitrifying much water containing nitrate-nitrogen while hardly causing a white turbidity phenomenon in water and to provide a method for raising aquatic animals, capable of reducing the frequency of change of breeding water while hardly causing the white turbidity phenomenon in the breeding water.SOLUTION: Nitrate-nitrogen dissolved in the breeding water W1 in a water tank or pond in which the aquatic animals are bred is removed by bringing the breeding water W1 into contact with a denitrifying material 23 containing sulfur and calcium carbonate. The method for raising the aquatic animals is for raising the aquatic animals in the breeding water W1 to which treatment water W2 after removal of nitrate-nitrogen is returned. The inflow water amount obtained by dividing the cubic volume per day of the breeding water W1 flowing into a treatment tank 21 filled with the denitrifying material 23 in which sulfur-oxidizing bacteria and aerobic microorganisms are grown by the mass of the denitrifying material 23 is at least 50 L/Kg per day, and the concentration of oxygen dissolved in the treatment water W2 flowing out of the treatment tank 21 is at least 3 mg/L.COPYRIGHT: (C)2013,JPO&INPIT【課題】水に白濁現象が生じ難く、硝酸性窒素を含む多くの水を脱窒処理できる硝酸性窒素の除去方法、及び飼育水に白濁現象が生じ難く、飼育水の交換回数を少なくできる水棲動物の飼育方法を提供することを目的とする。【解決手段】水棲動物を飼育している水槽又は池の飼育水W1を、硫黄と炭酸カルシウムとを含んでなる脱窒材23に接触させて、飼育水W1に溶存している硝酸性窒素を除去し、除去後の処理水W2を戻した飼育水W1の中で水棲動物を飼育する水棲動物の飼育方法であって、硫黄酸化細菌と好気性微生物とを生息させている脱窒材23が充填されている処理槽21に流入する飼育水W1の一日分の体積を脱窒材23の質量で割った流入水量が50L/Kg日以上であり、処理槽21から流出する処理水W2の溶存酸素濃度を3mg/L以上にすることを特徴とする水棲動物の飼育方法。【選択図】図3
