CONTROL DEVICE FOR NITRIFICATION TANK

摘要

PURPOSE:To maintain good quality of treated water and to prevent wasteful consumption of aeration energy, by measuring the distribution of the oxygen consumption rate in the down flow direction in a nitrification tank to recognize the nitrification condition in the nitrification tank and controlling the air flow rate to be blown to the nitrification tank and the sludge volume in the system according to the nitrification condition. CONSTITUTION:The distribution of the oxygen utilization rate in the down flow direction in the nitrification tank 2 is measured in a profile measuring instrument 5. The output of the instrument 5 and the set value of a standard profile setting part 15 are compared and the target value of a aeration air flow rate is calculated in a target aeration flow rate value computing part 14. The aeration air flow rate to the nitrification tank is controlled according to the above-mentioned target value of the aeration air flow rate in an aeration air flow rate controller 16. A daily average profile is calculated from the output of the instrument 5 in a day average profile computer 17. The target value of the sludge volume is calculated from the computed value of the above-mentioned daily average profile and the set value of the standard profile in a target sludge volume value computing part 19. The present sludge volume calculated in a sludge volume computing part 18 and the target sludge volume value are compared and the flow rate of the excess sludge is controlled in a sludge volume controller 20.