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Anaerobic Digestion Procedures
Recirculation Pumps/Heat Exchangers/Hot Water Pumps
Pre-Startup Checks
  1. Verify sludge recirculation pumps have power.
  2. Verify hot water pumps have power. 
  3. Open pump isolation valves. 
  4. Verify sludge recirculation pumps seal water system is functional.
  5. Check for missing, damaged, or misaligned rotating parts.
  6. Check suction and discharge piping for leakage or damage.
  7. Verify heat exchanger inlet and outlet valves are open.
  8. Verify heat exchanger inlet and outlet sludge temperature transmitters are functional.
  9. Verify digester inlet valve is open.
  10. Verify boiler is operational. 
  11. Follow all applicable safety rules, practices, and procedures.
  12. Do not operate if any of the checks listed above are unsatisfactory, and notify treatment plant supervisory staff.
Place Unit Into Service
  1. At the sludge recirculation pump panel, place the On/Off/Remote switch in the Remote position.
  2. At the hot water pump MCC, place the On/Off/Remote switch in the Remote position. 
SCADA Operation
  1. At the SCADA node, select desired pump mode: On/Off/Alternate.
  2. At the SCADA node, select desired temperature control valve mode: Auto/Manual.
  3. At the SCADA node, select desired sludge temperature setpoint.
  4. Periodically monitor pumps for proper operation.
  5. Periodically monitor heat exchanger temperatures for proper digester operation. 
Take Unit Out of Service
  1. At the sludge recirculation pump panel, place the On/Off/Remote switch in the Off position.
  2. At the hot water pump MCC, place the On/Off/Remote switch in the Off position. 
  3. Close system isolation valves. 
  4. Lock out pumps.
Digested Sludge Transfer
Pre-Startup Checks
  1. Verify each pump has power.
  2. Verify each pump seal water system is functional.  
  3. Verify digester sludge flow meter is functional.  
  4. Inspect pumps; ensure they are in proper operating condition.
  5. Check for any obvious misalignment of rotating parts, missing parts, or damage.
  6. Check suction and discharge piping for leakage or damage.
  7. Verify the pump isolation valves are open.
  8. Verify the pump discharge piping valves are open.
  9. Follow all applicable safety rules, practices, and procedures.
  10. Do not operate if any of the checks listed above are unsatisfactory, and then notify supervisory staff. 
Place Unit Into Service
  1. At the digester transfer pump panel, place the  On/Off/Remote switch in the Remote position.
SCADA Operation
  1. At the SCADA node, select the Auto mode.
  2. At the SCADA node, select desired pumping mode. 
Take Unit Out of Service
  1. At the digester transfer pump panel, place the  On/Off/Remote switch in the Off position.
  2. Close pump isolation valves. 
  3. Lock out pump. 
Hot Water Boilers/Cogeneration/Microturbine
Pre-Startup Checks
  1. The hot water boilers are operated from local control panels on the boiler.
  2. Verify the boiler has power.
  3. Open the isolating valves on the hot water piping for the boiler.
  4. Check to make sure that the isolating valves for the natural gas pilot, the natural gas, and the digester gas are open.
  5. Check that the low gas pressure switches on both the digester and natural gas trains and the common high gas pressure switch on the burner are not tripped. Manually reset the switches if necessary.
  6. Check to ensure the digester gas compressor is ready for operation. 
Place Unit Into Service
  1. On the side of the boiler control panel:
    1. Turn the circulating water pump On/Off switch to the On position.
    2. Turn the Local/Remote switch to the Remote position.
  2. On the front of the boiler control panel:
    1. Turn the burner On/Off switch to the On position.
    2. Turn the burner Manual/Auto switch to the Auto position.
  3. The automatic controls will start and stop the burner and modulate the firing rate as needed.  
SCADA Operation
  1. There is no boiler control from the SCADA.
  2. Monitor the boiler operation.
Take Unit Out of Service
  1. Turn the Off/Auto switch on the boiler local control station to the Off position.
  2. At the local control station, stop the boiler pump.
  3. If the boiler is to be off-line for an extended period of time, close the shutoff valves to the natural gas pilot, the natural gas fuel supply, and the digester gas fuel supply.
  4. If the boiler is to be off-line for an extended period of time, close the isolating valves on the hot water piping for the boiler.
  5. Lock out the boiler and the hot water pump.  
Digester Gas Storage
Pre-Startup Checks
  1. Verify all digester gas pressure indicator transmitters have power and are functional.
  2. Verify all digester gas flow meters have power and are functional.
  3. Verify all digester safety devices are functional.
  4. Verify the waste gas burner is functional and the pilot is lit.  
  5. Verify all waste gas valves are in their normal operating positions.
Take Unit Out of Service
  1. Refer to the equipment manual from the manufacturer of the digester safety devices.
Digester Gas Booster Compressor
Pre-Startup Checks
  1. Drain moisture from sediment trap and moisture traps using the manual drip handle.
  2. Verify the compressor has power.
  3. Verify compressor inlet valves are open.
  4. Verify compressor discharge valves are open.  
  5. Drain moisture from the manual drip traps on the inlet filter separator.
  6. Verify the compressor inlet pressure sensor, discharge temperature sensor, and flow meter are functional.  
Place Unit Into Service
  1. At the compressor local control panel place the Local/Remote switch in the Remote position.
SCADA Operation
  1. At the SCADA node, select Booster Compressor Run.
  2. Monitor the compressor operation.
  3. Monitor the digester gas flow to the heating equipment.
Take Unit Out of Service
  1. At the compressor local control panel, place the Local/Remote switch in the Local position.
  2. At the compressor local control panel, place the On/Off switch in the Off position.
  3. Close inlet and discharge isolation valves.
  4. Lock out the compressor. 
Waste Gas Burners
Pre-Startup Checks
  1. Verify the local control panel has power.
  2. Verify the digester gas flow meter to waste gas burners is functional.
  3. Verify the digester gas pressure transmitter upstream of flow meter is functional.
  4. Verify that natural gas main and pilot valves are open.
  5. Verify that the pilot regulator isolation valves are open.
Place Unit Into Service
  1. At the waste gas burner local control panel, place the On/Off switch in the On position.  
  2. Periodically drain the manual drip traps. 
SCADA Operation
  1. There is no SCADA control of the system.
  2. Periodically monitor the system operation from the SCADA.  
Take Unit Out of Service
  1. Turn off power at the local control panel.
  2. Close natural gas main and pilot valves.
  3. Close the digester gas valve.
  4. Lock out the burner.

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Last Updated: 9/16/2013 11:24:59 AM
Version 4.0.1