B3-CH-21-A n the shafts see Chapter Cooling options see Bevel-helical speed reduction gearboxes B3

Flender/Flender Gear Units/Bevel-helical speed reduction gearboxes B3

ower mani fold pressure set point (ii) Based on experience, Operator uses observed final effluent ammonia measurements to set maximum DO setpoints and percentage valve opening dead bands in Cells 1 & 1. (iii) The number of operational blowers and blower sp eeds are modulated to achieve the set point pressure and maintain DO and valve openings below the maximum setpoint and within the dead band respectively. (iv) Minimum valve opening positions are set to ensure minimum blower and diffuser airflows are maintained Although the ammonia concentrations are manually observed (from both the routine site measurements and online auto-analyzer) and not auto matically linked to the aeration control system, the chief Operators extensive experience on proc ess performance under varying influent quality and operating parameters has resulted in very efficient aeration control system. 1 During the 2 study, single blower was mostly in operation during the winter months, with second blower coming online during the summer months. Module 2 Air to Module 2 is supplied by six HST9 2NX Turbo blowers, supplied by ABS. Each reactor is supplied by three blowers (duty, assist, standby). The three blowers discharge into common manifold equipped with two pressure transmitters (the average value from the two is used for control purposes). Details of the blower and aeration control philosophy are given in the ABS Blower and aeration control function design specification manual. The simplified basic design aeration control philosophy is as follows: () Operator sets target pressure for the air manifold (ii) The blower speed and number of duty blowers are modulated to achieve the Operator set manifold pressure (iii) Operator sets DO setpoint for each aerobic cell and associated cell airflow control valve modulates to achieve setpoint DO. Each aerobic cell has dedicated airflow control value with actuator and feedback, an airflow meter and DO sensor (iv) To