METHOD FOR REMOVING NITRATE NITROGEN FROM RAW CITY WATER

摘要

PROBLEM TO BE SOLVED: To provide a method for removing nitrate nitrogen from raw city water whereby nitrate nitrogen can be removed from well water or groundwater to provide safe and hygienic city water and whereby concentrated wastewater and chemical-cleaning wastewater can be clarified at a low cost. SOLUTION: In a method for removing nitrate nitrogen from raw city water by pressurizing and introducing water to be treated into a primary side of a reverse osmosis membrane selectively allowing water to permeate, denitrifying bacteria and organic substances are added to concentrated nitrate nitrogen- containing wastewater generated at the treating step to reduce the nitrate nitrogen to a nitrogen gas by the reducing action of the denitrifying bacteria; and chemical-cleaning wastewater generated when the reverse osmosis membrane is cleaned is used as a source of the organic substance necessary for the denitrifying bacteria.