METHOD AND APPARATUS FOR REMOVING NITRATE NITROGEN IN WATER

摘要

PROBLEM TO BE SOLVED: To provide a method and an apparatus for continuously removing nitrate nitrogen in the water in which an organic hydrogen donor is not used, anaerobic treatment is not necessitated and nitrogen gas is not retained in the nitrogen removing system and which can be applied even to waste water containing high-concentration nitrate nitrogen.

SOLUTION: Nitrate nitrogen in the water is removed by using sulfur oxidizing bacteria, by mixing raw water with a circulation liquid, in a mixing/circulating tank 2, which circulates through a biological filtration column 3 packed with a sulfur carrier and formed with a biological membrane based on the sulfur oxidizing bacteria on its surface and feeding the mixture to the column 3 upward from the bottom by using a circulation pump 4 at 5-100/hourly space velocity to bring the mixture into contact with the sulfur oxidizing bacteria-based biological membrane forming the column 3 so that nitric acid is reduced to nitrogen.

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