| 摘要 |
<p>PURPOSE: A wastewater treatment apparatus capable of easily decolorizing and decomposing, at a low cost, a persistent nitrogen-containing dye such as an azo compound in wastewater containing a dye, being compact, having excellent durability and high processing power and ensuring long-term stable operation is provided. CONSTITUTION: The wastewater treatment apparatus comprises an obligatory anaerobic tank(1) for bringing wastewater containing a nitrogen-containing dye into contact with sulfate-reducing bacteria under obligatory anaerobic conditions, a nitrification tank(3) for bringing the wastewater into contact with nitrifying bacteria under aerobic conditions, and a denitrification tank(2) for bringing the wastewater into contact with the denitrifying bacteria under anaerobic conditions, wherein the obligatory anaerobic tank, the denitrification tank and the nitrification tank are disposed in the order of mention and a portion of the treated water(7) discharged from the nitrification tank is caused to return and circulate to the denitrification tank, and wherein the obligatory anaerobic tank, the nitrification tank and the denitrification tank are disposed in the order of mention and a re-aeration tank for bringing BOD decomposing bacteria into contact with the wastewater under aerobic conditions is disposed downstream of the denitrification tank.</p> |
