15 Thickened Sludge Pump Station Start Up
The Thickened Sludge Pump Station is equipped with three variable speed progressive cavity pumps. The general function of each pump is described below:
· TSPS Pump No. 1 only pumps sludge from the DAF to the Digesters
· TSPS Pump No. 2 is a “swing pump” and can pump sludge from either the DAF or the GT to the Digesters
· TSPS Pump No. 3 only pumps sludge from the GT to the Digesters
Typical pumping operation is described as follows:
· Pump operation (automatic or manual) is controlled by the Operator at SCADA
· GT Pumping operation runs for approximately 23 hours per day
· DAF pumping operation runs for approximately 6 – 7 hours per day
· GT Pumps No. 2 and No. 3 are rotated daily by the operators
The main GT Suction header is equipped with a tee that penetrates the TSPS Building wall between Pumps No. 2 and No. 3. Suction header isolation valves are installed on each side of the tee. During normal operation, those two suction header isolation valves are open. This allows GT pumping to rotate between Pumps No. 2 and No. 3.
The main DAF Suction header is equipped with a tee that penetrates the TSPS Building wall near Pump No. 1. A suction header isolation valve is installed between Pumps No. 1 and No. 2. This suction header isolation valve is closed during normal operation and isolates Pump No. 1 for DAF pumping.
The GT Discharge header is the “lower” pipe installed along the TSPS Building wall. The DAF Discharge header is the “upper” pipe installed along the TSPS Building wall. The Discharge Header isolation valve located near the Pump No. 1 discharge pipe and is closed during normal operation. This isolates the GT pumping from the DAF pumping.
Under normal operating conditions, the following conditions apply to the suction and discharge header isolation valves:
· At least one Digester Feed Valve must be open.
· Both GT suction header isolation valves are open (allowing GT pumping to rotate between Pumps No. 2 and No. 3).
· The DAF suction header isolation valve is open (this isolates Pump No. 1 for DAF pumping).
· The discharge header isolation valve is closed (this separates GT pumping from DAF pumping).
Each of the three pumps are also equipped with a dedicated suction isolation valve and a discharge isolation valve. These pump specific isolation valves are also open during normal operation.
The TSPS pumps treated sludge from either the Gravity Thickener or the Dissolved Air Flotation Thickener to the Digesters.
- GT: Gravity Thickener
- DAF: Dissolved Air Flotation
Watch for open tanks and high elevations. If working on or near equipment, watch for rotating parts.
- Verify that at least one feed valve is open at the Digester.
- Verify if sludge is to be pumped from the DAFT or from the GT.
Incorrect valve status.
Under normal operating conditions, the following conditions apply to the suction and discharge header isolation valves:
· At least one Digester Feed Valve must be open.
· Both GT suction header isolation valves are open (allowing GT pumping to rotate between Pumps No. 2 and No. 3).
· The DAF suction header isolation valve is open (this isolates Pump No. 1 for DAF pumping).
· The discharge header isolation valve is closed (this separates GT pumping from DAF pumping).
Operator I, knowledge of thickening and digestion processes and equipment controls.
- Access to SCADA workstation.
- Record activity to log book.
- Monitor DO levels at overflow via sampling system program.
- Monitor primary sludge flow to the Gravity Thickener (optimal flow rate = 213 gpm). Add Elutrient Water if influent flow falls below optimal rate.
a. From the Digester Control SCADA screen, verify that at least one digester feed valve {tag nos. 1505VLV5277J & 1505VLV5277Q} is open. The pumped sludge must have a discharge outlet at one of the digesters. If all of the digester valves are closed, there is a possibility of a pipe break.
2. Adjust suction header isolation valves. a. Locate the GT suction header tee. Locate the two suction header isolation valves {tag nos. 1503VLV5671G & 1503VLV5671H} on both sides of the GT Suction header tee. Open both GT suction header isolation valves if they are not already open. b. Locate the DAF suction header isolation valve {tag nos. 1503VLV5671F} that is installed between TSPS Pumps No. 1 and No. 2. Close the DAF suction header isolation valve if it is not already closed.
3. Adjust discharge header isolation valve. a. Locate the Discharge Header isolation valve {tag no.1503VLV5671I}. Close the Discharge Header isolation valves if it is not already closed.
Perform steps 4 – 7 for each of the three TSPS Pumps.
4. Adjust individual pump isolation valves. a. Open the pump discharge valve {tag nos. 1503VLV5100A, 1503VLV5200A & 1503VLV5300A}. b. Open the pump suction valve {tag nos. 1503VLV5100, 1503VLV5200 & 1503VLV5300}. Each pump is equipped with a stantion and four switches. The pumps can be placed into AUTO or HAND control at the stantion. Manual control is hard-wired to the VFD. Perform Step 5 for automatic control. Perform Step 6 or Step 7 for manual control. 5. Automatic pump control. a. Go to the TSPS Control Room and locate the breakers. i. Verify that Drive Unit Breaker Switch {tag nos. 1503BKR5100, 1503BKR5200 &1503BKR5300} is in the ON position. ii. Verify that VFD disconnect switch {tag nos. 1503SWI5100, 1503SWI5200 & 1503WSI5300} is in the ON position. iii. Locate the Local/Remote Switch {tag nos. 1503HS5100, 1503HS5200 & 1503HS5300} and place in REMOTE. b. Go to the pump specific stantion: i. Set HOA selector switch {tag nos. 1503HS5100, 1503HS5200 & 1503HS5300} to AUTO. ii. Push the START switch {tag nos. 1503HS5100A, 1503HS5200A & 1503HS5300A} c. Go to a SCADA workstation: i. Verify pump operation at HMI workstation. ii. Verify flow {tag nos. 1503FE/FIT5100, 1503FE/FIT5200 & 1503FE/FIT5300}.
6. Manual pump control from the stantion. a. Go to the TSPS Control Room. i. Verify that Drive Unit Breaker Switch {tag nos. 1503BKR5100, 1503BKR5200 &1503BKR5300} is in the ON position. ii. Verify that VFD disconnect switch {tag nos. 1503SWI5100, 1503SWI5200 & 1503WSI5300} is in the ON position. iii. Locate the Local/Remote Switch {tag nos. 1503HS5100, 1503HS5200 & 1503HS5300} and place in LOCAL. b. Go to the pump stantion: i. Set the HOA selector switch {tag nos. 1503HS5100, 1503HS5200 & 1503HS5300} to HAND. ii. Set the Forward/Reverse switch {tag nos. 1503HS5100E, 1503HS5200E & 1503HS5300E} to FORWARD. (REVERSE is typically used for removing a clog or obstruction from the pump. In that case, the JOG button {tag nos. 1503HS5100F, 1503HS5200F & 1503HS5300F} must be held down while choosing REVERSE). iii. Adjust the pump speed by turning the Speed Adjustment Switch {tag nos. 1503HS5100H, 1503HS5200H & 1503HS5300H}. The speed switch is hard-wired to the VFD.
7. Manual pump control from the Control Room. a. Go to the TSPS Control Room and locate the breakers. i. Verify that Drive Unit Breaker Switch {tag nos. 1503BKR5100, 1503BKR5200 &1503BKR5300} is in the ON position. ii. Verify that VFD disconnect switch {tag nos. 1503SWI5100, 1503SWI5200 & 1503WSI5300} is in the ON position. iii. Locate the Local/Remote Switch {tag nos. 1503HS5100, 1503HS5200 & 1503HS5300} and place in LOCAL. iv. Open the cover to the HMI {tag nos. 1503HMI5100, 1503HMI5200 & 1503HMI5300} and adjust the pump speed by pressing RUN, STOP RESET and turning the pump speed wheel.
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- Update log book.
- Update maintenance records (if applicable).
- Report any maintenance or attention that is required.
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