WASTE WATER TREATING METHOD AND WASTE WATER TREATING APPARATUS

摘要

PROBLEM TO BE SOLVED: To increase treatment speed when waste water treatment for lowering concentration of nitrate-form nitrogen by adding denitrifying bacteria to industrial waste water or the like containing the nitrate-form nitrogen is performed. SOLUTION: The waste water containing the nitrate-form nitrogen is diluted by prescribed dilution water so that concentration of the nitrate-form nitrogen in the waste water may be 5000 mg/l or less and then the denitrifying bacteria are added thereto to lower concentration of the nitrate-form nitrogen in the waste water. At that time, water by which salt concentration in waste water after dilution is within a proper range between 4% and 10% is used as the dilution water. Consequently denitrification activity by the denitrifying bacteria is greatly increased and waste water treatment speed is increased as compared with a case having salt concentration outside the proper range. Thereby time necessary to lower concentration of the nitrate-form nitrogen to a predetermined value is shortened by more than about half. COPYRIGHT: (C)2006,JPO&NCIPI