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WAS Pumping/Thickening Procedures
WAS Pumping/Thickening - WAS Pumps, DWAS Blowers, DWAS Pumps, Polymer System, GBT, TWAS Pumps
Process Flow Diagrams Process Plan and Section Diagrams
Plant Schematic WAS Pump Plan & Section
WAS Pumping Figure Thickening and Dewatering Plan View
 
WAS Pump
Startup Procedures
Flow Ratio Control Mode:
   1. On the Waste Activated Sludge Pump starter panel located in the Blower Building, select REMOTE operation. 
   2. Through the PCS, set the Waste Activated Sludge Pumps to AUTO mode and initiate a START command for
       pumps selected to operate.
   3. Through the PCS, set the Secondary Clarifier WAS Flow controller to RATIO mode.
   4. Through the PCS, set the Secondary Clarifier Withdrawal Ratio (adjustable between 0 and 100 Percent).

The total WAS flow rate to the Gravity Belt Thickener will be set via the Gravity Belt Thickener automatic startup sequence.

Remote Auto Control Mode:
   1. On the Waste Activated Sludge Pump adjustable speed drive panels, located in the Blower Building, select 
      REMOTE operation. 
   2. Through the PCS, set the Waste Activated Sludge Pump to AUTO mode and initiate a START command for 
       pumps selected to operate.
   3. Through the PCS, set the Secondary Clarifier WAS Flow controller to AUTO mode and enter a WAS flow set
       point for the Secondary Clarifiers.

Remote Manual Control Mode:
   1. On the Waste Activated Sludge Pump adjustable speed drive panels, located in the Blower Building, select 
       REMOTE operation.
   2. Through the PCS, set the Waste Activated Sludge Pump to MANUAL mode.
   3. Through the PCS, set the pump speed set point and initiate a pump START command.

Local Manual Control Mode:
   1. On the Waste Activated Sludge Pump adjustable speed drive panels, located in the Blower Building, select
       LOCAL operation.
   2. On the drive panel, set the pump speed set point and initiate a pump START command.
Shutdown Procedures

Flow Ratio Control Mode:
   1. Through the PCS, initiate a NORMAL SHUTDOWN of the Gravity Belt Thickener or set the Waste Activated
       Sludge Pump to MANUAL mode and initiate a STOP command to shut down the pump.

Remote-Auto Mode:
   1. Through the PCS, initiate a STOP command to shut down the pump.

Remote Manual Mode:
   1. Through the PCS, initiate a STOP command to shut down the pump.

Local Manual Mode:
   1. On the Waste Activated Sludge Pump drive panel, located in the Blower Building, initiate a STOP command
       to shut down the pump.

Polymer System
Pre-Startup Checks
  1. Verify that polymer is needed for the day that it will be made (the "Mix New Batch" light is illuminated).
  2. Verify there is adequate space in the polymer tank for a new batch to be made up.
  3. Verify polymer makeup local control panel has power.
  4. Verify polymer makeup local control panel shows no alarms.
  5. Verify there is an adequate amount of dry polymer on hand.
  6. Check with treatment plant supervisory staff if any unsatisfactory conditions exist.
  7. Follow all applicable safety rules, practices, and procedures.
Place Unit Into Service
  1. Push the Batch Start button on the Sludge Control Panel.
  2. Open the manual valve on the water line connected to the eductor. 
  3. Feed dry polymer into tank through the flexible hose connected to eductor.
  4. Close manual valve on water line.
  5. A "Batch Ready" light will illuminate after the mixing and aging processes are complete.
SCADA Operation
  1. None.
Take Unit Out of Service
  1. Stop polymer feed pumps at local control panels. 
  2. Turn all switches for the polymer system to the Off or Close position at the Sludge Control Panel.
Gravity Belt Thickener (GBT)
Pre-Startup Checks
  1. Verify there is power to the belt drive and control panel.
  2. Verify power to the GBT Feed Valves.
  3. Verify no foreign objects are on the belt and the belt is not frayed.
  4. Ensure the belt is centered on the rollers.
  5. Ensure the belt tracking system is working properly.
  6. Ensure polymer equipment is ready for operation.
  7. Ensure WAS pump is ready for operation.
  8. Ensure high pressure wash water is available.
  9. Ensure TWAS pump is ready for operation.
  10. Ensure plows (chicanes) are positioned on belt.
  11. Verify isolation valves in the wash water system are open.
  12. Follow all applicable safety rules, practices, and procedures.
Place Unit Into Service
  1. Turn on panel main breaker and place all selector switches in the Auto position.
  2. Energize panel control voltage.
  3. Press "Thickener System Start" button on the vendor supplied panel. The following should occur in sequence:
    1. The hydraulic power unit, the wash pump and the thickener belt drive should start within seconds of each other.
    2. After the pre-wetting cycle delay timer times out, the sludge pump and polymer unit should start.
  4. Adjust polymer dosing such that proper flocculation is observed in the bottom of the conditioning tank. .
  5. Adjust belt speed and throughput to optimize operation.
SCADA Operation
  1. There is no SCADA control of this equipment.
Take Unit Out of Service
  1. Shut down is in the reverse order as placing a unit into service.  After the WAS pump and the polymer system shut down, the belt will continue to run for 15 minutes to allow the belt cleaning function to occur.
  2. Solids buildup should be washed down daily to eliminate solids buildup on the GBT. 
Thickened Waste Activated Sludge Pump (TWAS)
Pre-Startup Checks
  1. Verify the thickened WAS flow meter is functional.
  2. Verify the thickened WAS sump level sensor is functioning correctly.
  3. Follow all applicable safety rules, practices, and procedures.
Place Unit Into Service
  1. At the TWAS pump local control panel, place the On/Off/Remote switch in the Remote position. 
  2. At the operator control workstation, ensure the TWAS hopper high level set point is set as required.
SCADA Operation
  1. When the GBT operates and the TWAS hopper at the end of the GBT reaches an operator adjustable high level set point the TWAS pump starts and continues pumping until the low level set point is reached.
  2. The thickened sludge is pumped to the anaerobic digesters for stabilization.
Take Unit Out of Service
  1. At the TWAS pump local control panel, place the On/Off/Remote switch in the Off position. 
  2. If the TWAS pump is scheduled for maintenance, use approved lock out tag out procedures as required.

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Last Updated: 9/16/2013 9:47:07 AM
Version 4.0.1