A METHOD FOR REMOVING TOTAL NITROGEN CONTENT IN WASTE WATER OF PROCESS FOR PREPARING COKE

摘要

PURPOSE: Provided is a method for removing total nitrogen content in wastewater from coke manufacturing process which can prevent bad influences such as eutrophication due to nitrogen on environment when discharged in hydrospheres and can reduce the amount of sodium hydroxide used for the pH control of wastewater. CONSTITUTION: At first, control the pH of wastewater within the range of 8.8 to 9.5 by controlling the dosage of sodium hydroxide. If the concentration of non-degradable NH3-N is below 270 ppm in wastewater, transfer the wastewater into denitrification tank(200) and if the concentration of non-degradable NH3-N is over 270 ppm, return the wastewater to distilling equipment(100) and add sodium hydroxide to let down the concentration of NH3-N in the range of pH 8.8 to 9.5. The circulation of wastewater from denitrification tank to nitrification tank(300) converts NH3-N into NO3-N in nitrification tank and converts NO3-N to nitrogen gas in denitrification tank and if the concentration of NO3-N in the nitrification tank is below 1 ppm, transfer the wastewater into settler(400) and if the concentration of NO3-N is over 1 ppm, add electro donor into wastewater to let down the concentration. If the concentration of total nitrogen in wastewater from thickener(500) is below 60 ppm, discharge that and if the concentration is over 60 ppm, return that to the distilling equipment. The electron donor is selected from methanol, ethanol, acetic acid and acetone.