Metro Aeration
VSG Enviromation’s “OptimAir” Controls Onondaga County’s Largest Wastewater Treatment Plant
The Metropolitan Syracuse Sewage Treatment Facility serves primarily the City of Syracuse and the adjacent metropolitan communities. The Onondaga County Department of Drainage and Sanitation contracted with M. A. Bongovanni Construction Co. to remove six (6) mechanical aerators from eight (8) basins and replace these with a multi-disk, diffused air system.
Four (4) 100-horsepower, Hoffman centrifugal blowers were installed on each of the eight (8) aeration basins, for a total of thirty-two (32) blowers. VSG Enviromation provided sixteen (16) local blower control panels, utilizing Allen-Bradley SLC5/03 programmable controllers, to monitor and control the blowers. The blower controls include:
- Motor Current and Surge Control.
- Motor/Blower Bearing Temperature.
- Motor/Blower Bearing Vibration
- Air Flow Control
- Blower Normal and Fault Shutdown
Of the eight (8) aeration basins, four (4) are on Treatment Train A and four (4) on Treatment Train B. VSG Enviromation provided two (2) Aeration Process Control Panels to operate each train independently. Process control is through an Allen-Bradley SLC5/05 programmable controller, and is based on regulating the amount of airflow to each aeration basin to meet a setpoint for Dissolved Oxygen (D.O.). Readings are received from two (2) D.O. analyzers located at each aeration tank. The system software provides for selection of control for each individual tank from either D.O. analyzer or a combination of both. With OptimAir, air flow is regulated in two steps. First air delivery from each blower is adjusted by modulating the inlet air damper valve. Secondly, the control system is able to select the number of blowers needed to operate in a basin based on D.O. requirements. OptimAir even has logic for fault monitoring, shutdown and auto start of back-up blowers.
The local blower control PLC’s communicate with the aeration control PLC’s via an A-B Data-Highway. The Aeration PLC’s are connected to Ethernet TCP/IP local area network, which is part of the Metropolitan Sewage Plant’s SCADA System. Blower motor control and monitoring is accomplished through a single pair of wires using Allen-Bradley’s SMC solid state starters and Allen-Bradley Remote I/O serial communication. Typical functions performed and data being collected through the Remote I/O link are:
- Blower Drive Enabled
- Voltage Each Phase
- Blower Running
- Current Each Phase
- Blower Drive Faults
- Elapsed Run Time
- Blower at Full Speed
- Power Factor
- Start/Stop Control
- Thermal Usage