BIOLOGICAL WATER TREATING DEVICE

摘要

PROBLEM TO BE SOLVED: To calculate an NOx -N production quantity from ORP variation quantities at an aeration tank inlet and its outlet and to control an aeration air quantity and a circulation flow rate. SOLUTION: An ORP variation quantity arithmetic means 320 calculates the ORP variation quantities from the measured values of ORP meters 200, 210 respectively at the aeration tank inlet and the outlet. A nitrated quantity arithmetic means 330 calculates an NOx -N production quantity from the ORP variation quantities. An air quantity adjusting means 500 controls an opening degree of a valve 100 at a suction side of a blower 110 based on the NOx -N production quantity. Thus, the discharge water quality can excellently be maintained with the ORP variation quantities.