MARINE PARK WATER RECLAMATION FACILITY - Operations and Maintenance Manual

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Section 50 - In-Plant Washdown Pump Station

50.01General Overview
50.02Design Criteria
50.03Computer Assisted Control Strategies
50.04Operating Strategies
50.05Troubleshooting
50.06Safety
50.07Records/Sampling

50.01 General Overview

Once each water holding structure has been drained with the RAS pumps, the In-Plant Washdown Pump Station is used to collect and pump the water from the hoses used to spray the walls and floor. Each pump station houses two submersible pumps having a capacity of 270 gpm. The washdown water is pumped to the influent pump station.

50.02 Design Criteria

IN-PLANT PUMPS
Number of Units2
Phase 24 (2 new, 2 existing)
TypeSubmersible
Capacity270 gpm
Horsepower, Each10

50.03 Computer Assisted Control Strategies

50.03.a. General Overview

At the MPWRF, the In-Plant Washdown Station submersible pumps are used to pump down residual water from tank washdowns back to the influent pump station. The pump station level is monitored by the SCS, and alarms are provided in the event of high or low levels in the wet well.

50.03.b. Control Strategies

This section tells the operator how to interact with the PLC and the SCS, describes each control loop and describes how and where alarm and equipment status is transmitted.

50.03.b.1. In-Plant Washdown Pump Station

Loop Function:Monitors the In-Plant Washdown Pump Station pumps on status (ON).
Monitor in-plant sump level and provides auto sequencing of pumps.
Monitors and provides alternate pump cycling.
Instrumentation:HS-14051, HS-14052, HS-14253, HS-14254 (HAND/OFF/REMOTE handswitches [HOR])
(Located at the in-plant Washdown pump station panel LP-14051 and LP-14253).

HS-14051, HS-14052, HS-14253, HS-14254 (START/STOP pushbuttons [SS])
(Located at the in-plant Washdown pump station panel LP-14051and LP-14253).

QL-14051, QL-14052, QL-14243, QL-14254 (Pump on lights [ON])
(Located at the in-plant Washdown pump station panel LP-14051 and LP-14253).

LSHH-14051, LSHH-14253 (Pump station level switch, sends high wet well level alarm to PLC)
(Located in wet well).

LSH-14051, LSH-14253 (Pump station level switch, sends START LAG pump signal to PLC)
(Located in wet well).

LSM-14051, LSM-14253 (Pump station level switch, sends START LEAD pump signal to PLC)
(Located in wet well).

LSL-14051, LSL-14253 (Pump station level switch, sends STOP pump signal to PLC)
(Located in wet well).

LSLL-14051, LSLL-14253 (Pump station level switch, sends low wet well alarm to PLC)
(Located in wet well).
Alarms:LAHH-14051, LAHH-14253 (Pump station high level alarm).

LALL-14051, LALL-14253 (Pump station low level alarm).

QL-14051, QL-14052, QL-14253, QL-14254 (Pump moisture light [MOIST], indicates pump seal is leaking water.)

TLH-14051, TLH-14052, TLH-14253, TLH-14254 (Motor high temperature light [MOTOR], indicates high electrical motor temperature.)
PLC/SCS Function:Monitor pump on status (OOR), QL-14051, QL-14052, QL-14253, QL-14254.

Monitor HOR handswitch REMOTE position (OOR), QL-14051, QL-14052, QL-14253, QL-14254.

Determine run pump fail in REMOTE and provide alarm (RUN FAIL), QA-14051, QA-14052, QL-14243, QL-14254.

Monitor pump fail from local panel and provide alarm (LOCAL FAIL), QA-14051 QA-14052, QA-14253, QA-14254.

Monitor high-high level switch and provide alarm, LAHH-14051, LAHH-14253.

Monitor low-low level switch and provide alarm, LAHH-14051, LAHH-14253.

Monitor pump sequencing level switches, LSH-14051, LSH-14253 (START LAG), LSM-14051, LSM-14253 (START LEAD), LSL-14051, LSL-14253 (STOP).

Provide pump sequencing.

Operation:

  1. When selected to REMOTE, a pump is started when the level in the wet well reaches the START LEAD level switch and, if required, a second pump is started by the START LAG level switch. Both pumps are stopped when the level reaches the STOP level switch. Typically, only one pump will run and the LEAD pump will alternate each time the START LEAD level is reached.

50.04 Operating Strategies

50.04.a. General Operating Strategy

The In-Plant Pump Station pumps will shut down if moisture is detected in the pump casing or if the motor overheats as sensed by the temperature switch.

When selected to REMOTE, an In-Plant Pump Station pump is started when the level in the wet well reaches the START LEAD level switch. If required, a second pump will be started when the wet well level reaches the START LAG level switch. Both pumps stop when the wet well level reaches the STOP level switch. Typically, only one pump will run and the LEAD pump will alternate each time the START LEAD level is reached.

50.04.b. Normal Operating Conditions

Note: Normal plant operations will use the PLC and the SCS CRT to monitor the operation of the In-Plant Washdown Pump Station. Local control of equipment will be covered under section 50.04.c. Alternate Operating Conditions.

50.04.b.1. In-Plant Washdown Pump Station

The normal mode of operation of the In-Plant Washdown Pump Station is to place the pump controls in REMOTE, allowing PLC/SCS control. The PLC monitors the pump operation and wet well level. Equipment Status Table 50.04.b.1 summarizes the proper equipment configuration for normal operation.

EQUIPMENT STATUS TABLE 50.04.b.1.
Equipment DescriptionStatus
P-14051 (Sump Pump #1)HS-14051 Handswitch in REMOTE
P-14052 (Sump Pump #2)HS-14052 Handswitch in REMOTE
P-14253 (Sump Pump #3)HS-14253 Handswitch in REMOTE
P-14254 (Sump Pump #4)HS-14254 Handswitch in REMOTE


50.04.c. Alternate Operating Conditions

50.04.d. Startup/Shutdown Conditions

50.04.e. Key Control Data and 4 Level Alarm Table

50.04.f. Contingency Plans

A contingency Plan is written to handle an unpredictable occurrence that has a reasonable chance of happening. Most Contingency Plans deal with situations where having a written procedure can help prevent loss of a unit process, handle a process upset or respond to a hazardous situation. The following is a list of Contingency Plans developed for the In-Plant Washdown Pump Station process. The plans are kept in the Contingency Plan Notebook located in the Operator Laboratory and the Shift Supervisor Office.

50.04.g. Standard Operating Procedures

A Standard Operating Procedure (SOP) is written to handle operator activities performed on a regular but not necessarily daily basis. Most SOPs deal with potentially hazardous activities making it important that a written, step-by-step procedure be available. The following is a list of SOPs developed for the In-Plant Washdown Pump Station process. The procedures are kept in the SOP Notebook located in the Operator Laboratory and the Shift Supervisor Office.

50.05. Troubleshooting

See Section 75 Maintenance Plan for troubleshooting dealing with the operation of the In-Plant Washdown Pump Station.

See Table 50.05.a.1. for troubleshooting the In-Plant Washdown Pump Station pumps.


TABLE 50.05.a.1. - Troubleshooting the In-Plant Washdown Pump Station pumps
ObservationProbable CauseSolution
High level alarm at pump station.Pumps not pumping.Place pumps in REMOTE.
Pumps are plugged.Clean scrubber media with muriatic acid.
Insufficient scrubber chemical addition.Lock out and clean pumps.
Excessive flow in to lift station.Determine source and reduce flow as possible.
Pump(s) MOTOR alarm activated.Lock out and notify maintenance.
Pump(s) MOIST alarm activated.Lock out and notify maintenance.


50.06. Safety

50.06.a. Confined Spaces

50.06.a.1. In-Plant Washdown Station

The operator is responsible for reviewing the SOP on Entering the In-Plant Washdown Station. A confined space entry form must be filled out and properly signed before entry into the channel.

50.07 Records/Sampling

50.07.a. Sampling Schedule

Not used.


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