section 17924 control strategies - eandm

SECTION 17924CONTROL STRATEGIES

PART 1 - GENERAL

1.01 Summary

A. Scope: This section provides functional descriptions of the PLC and SCADA computer softwarerequirements for the Plant PLC based control system as indicated on the drawings and asdescribed within.

B. Related Sections: The following list of related sections is provided for the convenience of theContractor. It includes the commonly referenced sections that are in-general applicable to allequipment supplied. This list does not excuse the Contractor from any requirement given insections not specifically listed below. Where there is a difference between this specification andany other specifications the conflict shall be resolved at the sole discretion of the Engineer.

Section Title

Section 01300 Submittals

Section 01340 Shop Drawings, Product Data, and Samples

Section 01360 Operating and Maintenance Information

Section 01620 Protection of Materials and Equipment

Section 01660 Installation, Testing and Commissioning

Section 01661 Instruction of Operators and Maintenance Personnel

Section 01720 Record Drawings

Section 11225 Effluent Pump Station

Section 11330 Influent Screening and Compacting Equipment

Section 11350 Screw Press Dewatering Equipment

Section 11700 Immersed Membrane Bioreactor System

Section 11820 Process Blowers

Section 16010 General Electrical Provisions

Section 16155 Motor Starters

Section 16160 Pilot Devices

Section 16200 Overcurrent Protective Devices

Section 16250 Motor Control Center

Section 16261 Automatic Transfer Switch

Section 16300 Electrical Service Equipment

Section 16320 Surge Protective Devices

Section 16324 Uninterruptible Power Supply

Section 16330 Variable Frequency Drives

Section 17010 General Requirements, Instrumentation

Indian Health Services Tule River Community Wastewater SystemAugust 2010 Control Strategies261-004-100 17924-1

Section 17015 System Integrator Pre-Qualifications Form

Section 17110 Instrumentation and Control Systems

Section 17201 Control Panels

Section 17506 Extended Warranty and Maintenance

Section 17510 Factory Acceptance Tests

Section 17512 Site Acceptance Tests

Section 17902 SCADA System

1.02 References

A. All work specified herein shall conform to or exceed the applicable requirements of the referencedportions of the following publications to the extent that the provisions thereof are not in conflict withother provisions of these specifications.

Reference Title

ANSI C80.1 Electrical Rigid Steel Conduit

UL 1 Flexible Metal Conduit

UL 5 Surface Metal Raceway and Fittings

UL 6 Electrical Rigid Metal Conduit - Steel

UL 514B Conduit, Tubing and Cable Fittings

UL 651 Schedule 40 and 80 Rigid PVC Conduit and Fittings

NEMA RNI-2005 PVC Externally Coated Galvanized Rigid Steel Conduit andIntermediate Metal Conduit

NEMA TC-2-2003 Electrical PVC Tubing and Conduit

NEMA TC-3-2004 PVC Fittings for Use With Rigid PVC Conduit and Tubing

PART 2 - PRODUCTS (NOT USED)

PART 3 - EXECUTION

3.01 Preparation

A. SCADA System, PLC and Autodialer Strategies - General

1. Any communication failures between either of the SCADA Server computers and the variousPLCs shall be logged as a SCADA Alarm.

2. The Wonderware SCADA system shall be capable of monitoring and controlling all PLCcontrol based operations implemented from any of the various PLCs.

3. The Treatment System shall be provided with both manual control of the various WastewaterSystem PLC controlled systems and automatic control of the Wastewater System PLCcontrolled systems.

B. SCADA System Control Strategies


1. SCADA Screen Display: The SCADA system shall utilize a screen display that consists of twoparts. The first part shall consist of a common template or frame that allows personnel toperform various SCADA related tasks or functions. Within the common template or frame, aview port or "Main Window" shall be provided that shows the selected window of any of thevarious windows or graphic displays that are contained within the major SCADA DisplayGroups. Determine exact screen hierarchy with Engineer during program development. Thecommon template or frame shall provide personnel with the following control functions:

2. Selection of the major SCADA Display Groups: A series of tabs or buttons shall be providedalong the top edge of the template. Each of the tabs or buttons shall cause a window from theselected SCADA Display Groups to be displayed in the view port.

a. Select "System Overview".

b. Select "Pre-Treatment Overview".

c. Select "MBR Systems Overview".

d. Select "Solids Overview".

e. Select "Effluent Pumping Overview".

f. Select "Effluent Disposal Overview".

g. Select "Miscellaneous Systems Overview".

h. Select "Alarm Log".

i. Select "Trending".

j. Select "System Library".

3. Select "Home": A button shall be provided that when activated, changes the view port todisplay the "System Overview window.

4. Select "GOTO": A button shall be provided that when activated, brings up a pop-up windowthat contains miniature displays or "thumbnail" view of each of the available windows providedas part of the various Graphic Displays Groups including the name of each window. From thepop-up window, plant personnel can select any of the windows of the Graphic Displays Groupsto appear in the view port. In addition, if an alarm has occurred, an "alarm" message shallflash in the miniature display of the system where the alarm shall occurred.

5. Select "Login": A button shall be provided that when activated, brings up a pop-up window thatwill allow an operator to login into the SCADA system. The pop-up window will allowpersonnel to enter both a user name and a password. The pop-up window will indicate theaccess level of the user. The SCADA system shall include four security access levels:

a. "System Programmer" Level: This level provides total access to all functions associatedwith the SCADA system and control.

b. "Operator" Level: This level provides personnel with the ability to view any windowsavailable for the four major display groups and the ability to initiate any control actionssuch as acknowledgment of alarms, changing setpoints and activating manual start/stopcontrols.

c. "Security" Level: This level provides personnel with the ability to view any windowavailable from the four major display groups only. Alarms may be acknowledged but noother control actions may be performed.

d. "Display" Level: This level provides personnel with the ability to view any window availablefrom the four major display groups only. No control actions are permitted.


e. Select "Help": A button shall be provided that when activated, brings up a pop-up menuthat indicates the window from the Graphic Display Group that was last selected or iscurrently in display at the view port and provides written text describing any controlfunctions or special operation instructions that may be associated with the processesassociated with this specific window of the Graphic Display Group.

6. Computer Function Keys- The twelve computer keyboard function keys shall be used asGlobal Function Keys. The actual functions will be defined with the Owner during the submittalprocess. The remaining function keys shall be used as system function keys. The functionkeys will be as defined below:

a. Function Key F1 to F12 - These function keys may be used as links to functionsassociated with the current Screen Displayed in the "Main Window," links to the variousOverview Screens, or links to other SCADA applications associated with the TreatmentPlant.

b. For every SCADA Screen provides links to other associated SCADA Screen that maintaincontinuity through the process as noted on the Process Flow Sheets and the P&IDs of theContract Drawings.

7. Historian - The System Integrator shall submit for approval a listing of up to 400 tags thatrepresents what process information will be archived and available via the Historian.Incorporate recommendations by the Owner or the Engineer.

8. Graphic Displays - Common Features:

a. All symbols, devices and piping shall be pre-configured symbols from the most currentversion of the Wonderware Intouch software. Custom generated symbols shall not beused unless they have been pre-approved prior to the creation of the new graphicalscreens.

b. Common Graphic Features:

1) Every Pump or Blower shall change color to indicate its current operational state asfollows:

a) Running: Steady Green

b) Failure: Flashing Red

c) Not Ready: Steady Red

d) Off or Not in Service: Gray

2) Every Automatic valve shall change color to indicate its current operational state asfollows:

a) Open: Steady Green

b) Failure: Flashing Red

c) Closed: Steady Red

d) Off or Not in Service: Gray

3) Any measured values that are displayed (e.g. flow, level, turbidity, etc) shall bepresented in a digital display that indicates true engineering values. The digitaldisplays shall mimic actual digital display meter in their graphical presentation and shallindicate the engineering unit scale. Only one display style shall be used throughout alldisplay screens.


4) Any measured values that represent level shall also graphically display acorresponding level change of state in a "tank" or "vessel" type system. The selectedsymbol for each level value shall closely match the actual tank or vessel.

5) All real-time trend displays shall indicate the engineering units and increments for boththe vertical and horizontal scales. Where time scales are utilized, indicate timeincrements in an hours/minutes type display.

6) All real-time trend displays shall be provided with a legend indicate what each colortrace represents.

7) Except for the "System Overview" Display, all process piping shall be shown on thescreens in a manner that correctly indicates process flow.

8) Trend Display format shall be approved by the Owner during the submittal process:

a) All real-time trend displays shall indicate the engineering units and increments forboth the vertical and horizontal scales. Where time scales are utilized, indicate timeincrements in hours/minutes/seconds type display.

b) All real-time displays shall be provided with a legend indicating what each colortrace represents.

9) With the exception of the "System Overview" Display, the "Pre-Treatment Overview'Display, the "MBR Systems Overview", the "Solids Overview" Display, the "EffluentPumping Overview", the "Effluent Disposal Overview", the "Miscellaneous SystemsOverview", and the Display, all process piping shall be shown on screens in a mannerthat correctly indicates process flow as shown on the P&ID drawings of the contractset. In addition, all manual valves will be shown, except for any manual valve deemedby the Owner as not necessary for SCADA representation.

10) For each SCADA Screen, provide the means to toggle on or off display of the variousinstrumentation and device tags as shown on the P&IDs of the contract drawings.

11) Pop-Up Windows:

a) Pop-Up windows, when used, shall have an exit button.

b) All pop-up windows, when displayed shall be repositionable by an operator to anysection of the Main Window, using a click and drop method.

c) Analog Digital Displays: Each analog digital display shall display value and unitsonly. Each of these displays shall be provided with a pop-up window that displaysthe Instrument Loop ID, Actual Device Name, Process Variable, Zero, Span, AlarmStatus, and any alarm or time delay set points associated with analog digitaldisplay. Set points shall be adjustable from these pop-up windows and protectedwith currently logged on operator's password.

d) Section Display Pop-Up Windows: A Section Display is defined as a smaller area ofa process and consists of a set of SCADA components that work together toperform a plant process operation. The status, alarms, and set points associatedwith this Section shall be gathered together into a single pop-up screen thatcontains several folders.

C. SCADA Screen Display Groups

1. General:

a. In addition to the SCADA screens listed in this specification section and the MBRmanufacturer provided SCADA Screens, the Control System Integrator shall develop up to


50 main SCADA screens and the necessary popup screens identified during the submittalprocess. Some of the key screens are identified below.

b. For all SCADA Screen Group "Overview Screens" provide indication of general runningand failure status associated with each of the SCADA Screens within their respectiveSCADA Screen Group.

c. For all SCADA Screen Group "Overview Screens" provide a common running and alarmstatus for the other SCADA Screen Groups with a link back to the "WWTP SystemOverview."

d. For all "Overview Screens" provide an alarm display of the last three alarms.

e. For the SCADA Screens contained with in a SCADA Screen Group, provide an alarmdisplay of the last three alarms associated with that SCADA Screen Group.

f. For each SCADA Screen contained within a SCADA Screen Group, provide an ActiveFactory Trending Display Pop-up Screen to display specific parameters associated withthis SCADA screen group. The Active Factory Trending Display shall save the settingmade by the plant staff.

g. For each SCADA Screen except for the "System Overview Screens", provide pop-upwindows for each component that requires input from plant staff such as setpoints andcontrol functions.

h. For each SCADA Screen except for the "System Overview" screens, provide a pop-up helpscreen that includes general descriptions of the process associated with that screen, areference to the associated Process Flow Sheet, a reference to the associated P&IDsheets and any commentary that is identified during startup.

i. For each SCADA Screen except for the "System Overview" screens, provide a pop-updocumentation screen that provides access to a Microsoft Word Document or Database fordocumentation of events, actions or help tips. The document shall be in a table format thatincludes a place for author's name, time and date stamp and a comment field.

2. SCADA Screen Group #1 - "System Overview":

a. Graphic Screen - "Project Site Map" - Note Project Site Map provides links to the WWTPand the other project facilities that have SCADA Screens:

1) The following components shall be included in this display including all featuresspecifically listed within the control loop descriptions provided later in this specificationsection:

a) A schematic type map of the project providing links to the WWTP and the variousremote sites covered by the SCADA application

b. Graphic Screen - "WWTP System Overview" provides links to the "Overview" displays inthe other SCADA Screen groups.1) The System Overview Screen shall provide indication of general running and failure

status associated with each of the SCADA Screen Groups.

c. Graphic Screens for all of the remote facilities covered under the SCADA system.

3. SCADA Screen Group #2 - Pre-Treatment Overview:

a. Graphic Screen - "Influent Lift Station"

b. Graphic Screen - "Headworks"

4. SCADA Screen Group #3 - "MBR Systems Overview" should match MBR manufacturer'sscreen:


a. Graphic Screen - "MBR Systems Overview" provides links to the other screens in this

group.

b. Graphic Screen - "Anoxic Basins"

c. Graphic Screen - "Mixed Liquor Pump Station"

d. Graphic Screen - "Aeration Basins"

e. Graphic Screen - "Membrane Basins"

f. Graphic screen - "Permeate Pump Station"

g. Graphic screen - "Clean-In-Place Station"

h. Graphic Screen - "Process Blowers"

i. Graphics Screen - "Membrane Blowers"

j. Graphic Screens provided with the membrane manufacturer SCADA Application will beplaced in this group.

5. SCADA Screen Group #4 - "Solids Overview":

a. Graphic Screen - "WAS pump and Polymer System"

6. SCADA Screen Group #5 - "Effluent Pumping Overview":

a. Graphic Screen - "Effluent Storage Tank and Pump Station"

7. SCADA Screen Group #6 - "Effluent Disposal Overview":

a. Graphic screen - "Effluent Disposal Fields"

1) Provide a map style graphic display.

2) For each Effluent Disposal field, the daily total flow, and totalized flow shall bedisplayed and recorded for 7 days.

3) For each Effluent Disposal field, flow totals shall have resettable and non-resettablerecorders.

4) For each Effluent Disposal field, the instantaneous flow shall be displayed.

5) For each Effluent Disposal field, the control and status of all Effluent Disposal Fieldvalves shall be displayed and implemented.

6) Indicate the order that each Effluent Disposal Field is being served and indicate whichEffluent Disposal Fields are "Out-Of-Service".

7) Indicate which section of an Effluent Disposal Field is being served and indicate whichsections are "Out-Of-Service".

8) All plant staff the ability to change the Effluent Disposal Field Order and the timedurations for each section valve.

9) Indicate which Schedule is in use.

b. Graphic Screen - Summer Schedule, Table Format, operator adjustable.

c. Graphic Screen - Winter Schedule, Table Format. Operator adjustable.

8. SCADA Screen Group #7 - "Miscellaneous Systems Overview'

a. Graphic Screen- Utility Power and Standby Power Systems

9. SCADA Screen Group #8 - "Alarm Log":


a. Graphic Screen - "Wastewater Treatment Plant": Display all process alarms conditionsrelated to the Domestic Treatment Plant. Provide a means to test, acknowledge, reset andsilence alarms.

b. Graphic Screen - "Remote Sites": Display all process alarms conditions related to theother existing remote sites. Provide a means to test, acknowledge, reset and silencealarms.

10. SCADA Screen Group #9 - "Trending":

a. Provide an Active Factory Trending Display to allow plant staff to display any combinationof available process conditions. The Active Factory Trending Display shall save the settingmade by the plant staff.

11. SCADA Screen Group #10 - "System Library":

a. Graphic Screen - System Library

1) Provide links to the pop-up help screens associated with each SCADA graphic screen.

2) Provide links to the pop-up documentation screens associated with each SCADAgraphic screen.

b. Graphic Screen - "Communication Status and Alarms"

1) Provide a running and failure status associated with the communication network tied tothe various PLCs, VFDs and the power monitoring system.

c. Graphic Screen - "Power Monitoring System"

1) Provide a SCADA screen that provides full access to the Power Monitoring Software.Configure Software to provide power parameters associated with the Power Systemincluding"

a) Most common electrical parameters including Instantaneous voltage, current and %Total Harmonic Distortion

b) Historical Archival and Trending of electrical parameters

3.02 Installation

A. Basic Operating Control Strategies

1. General: The following "Control Strategy" descriptions define the key features associated withthe plant. These control strategies provide the system integrator with an overview of theoperation parameters that will be expected in each area. The system integrator will developthe PLC programs for each of the PLCs based on the operating strategies described below,and in keeping with the basic function described below.

2. Motor: Where the P&IDs define that a motor load is controlled by a PLC, all of the status andalarm functions shall be displayed on SCADA. Both a PLC automatic based control strategyand a manual overall control via SCADA shall be provided for each motor. All setpoints shallbe accessible and modifiable via SCADA.

3. Valve: Where the P&IDs define that a valve is controlled by a PLC, all of the status and alarmfunctions shall be displayed on SCADA. Both a PLC automatic based control strategy and amanual overall control via SCADA will be provided for each valve. All setpoints shall beaccessible via SCADA.

4. Packaged System; Where the P&IDs define that a package system is monitored by SCADA,all of the status, control and alarm functions that are accessible by the Packaged System'sOperator Interface Terminal shall be also accessible through the Plant SCADA system. Thesepackage systems include:


a. Headworks Screen

b. MBR System including the Anoxic Basins, Mixed Liquor Pump Station, Aeration Basins,Membrane Basins, Permeate Pump Station, Clean-In-Place Station, Process Blowers, andMembrane Blowers.

c. Polymer Blending System

5. Autodialer Alarms - Each equipment failure, low-low state, low state, high state, high-highstate, communication failures, normal power failures, or UPS power failures shall be reportablevia SCADA.

6. Autodialer Status - All instrumentation analog values, in actual engineering units shall beaccessible from the Autodialer.

7. Instrumentation:

a. Where the P&IDs define that an instrumentation device is monitored by a PLC, all statusand alarm functions shall be displayed on SCADA.

b. All instrumentation having an analog value shall have a PLC based High-High, High, Low,and Low-Low alarms that can be monitored by SCADA. Each alarm shall have a PLC-based set point that can be adjusted via SCADA. Each alarm shall have a means to beenabled or disabled via SCADA.

c. All instrumentation having an analog value shall be trended historically and shall beavailable for staff to trend and perform analysis via the Historian and Active Factory.

B. Control Strategy - Influent Lift Station

1. General: The Influent Lift Station receives influent flow from the collection system, siteoverflows and plant drains. The influent pump station controls the flow steam to theHeadworks. The influent wet well is equipped with two submersible pumps - Influent LiftStation Pump 1 (P-301) and Influent Lift Station Pump 3 (P-303) with provisions for a futurepump designated as Influent Lift Station Pump 2 (P-302). The Influent Wet Well is equippedwith two sets of sump level measurement - a submersible level transducer LE/LT 310 (usedfor automatic control of the Influent Pumps) and a set of three float switches. The submersibleis used for PLC based control of the Influent Lift Station Pumps via a series of level set points.The level switches provide alarm status regarding the wet well level as well as backuphardwired control of the Influent Chopper Pumps in the event of either a failure of the PLC orthe submersible level transducer. Automatic and remote control for each pump is provided bythe Influent Lift Station Control Panel (ILSCP) PLC. Normal automatic operation is to allow theInfluent Lift Station Pumps to operate in a lead/lag/standby configuration based on level setpoints. Influent Lift Station pumping operations will be controlled by the ILSCP PLC asdescribed below:

a. When the Influent Lift Station Pumps are set for automatic, the Influent Pumps No. 1, No. 3and future Influent Pump No. 2 will operate in a lead/lag/standby manner with automaticalternation of the pumps. The purpose of the automatic alternation scheme shall be toequalize the runtime of each of the two (and future third) pumps. Automatic alternationshall designate the pump with the shortest runtime, as the lead pump, the next shortest asLag, etc.

1) Provide manual override of the automatic alternator at SCADA and the PCP OIT thatallows plant personnel to designate the "Lead Pump", "Lag Pump", and "StandbyPump". When manual override is active, the pumps will alternate in this fixed sequenceuntil placed back to automatic alternation. For example, when two pumps are selectedfor automatic control, the manual override will allow a plant operator to choose aLead/Standby with Alternation or a Lead/Lag with Alternation scheme.


2) If only one pump has its Hand/Off/Automatic Selector Switch in the "Automatic"position, then that pump will operate as the lead pump.

3) If only two pumps have their Hand/Off/Automatic Selector Switches in the "Automatic"position, then those two pumps will operate in a lead/lag manner with automaticalternation.

b. The following control level set points shall be provided:

1) Lead Pump Start and Stop Set Points

2) Lag Pump Start and Stop Set Points

3) Standby Pump Start and Stop Set Points

c. Provide at SCADA and the OIT, level alarms based on the level switches.

d. If all the enabled pumps in the Influent Lift Station Wet Well are running but the level in thewet well continues to rise to the High-High Level Switch (LSHH 320) then an alarm isgenerated at the PLC. A notification should be via the SCADA system.

2. Influent Lift Station Pump No. 1 (P-301):

a. Typical of Influent Lift Station Pump No. 2 (P-302, a future pump) and Influent Lift StationPump No. 3 (P-303)

b. Function: Influent Lift Station Pump No. 1 is one of three pumps (one of which is a futurepump) that will control the flow out of the Influent Lift Station Wet Well.

c. Local Control: The pump is equipped with a full voltage non-reversing starter to allow on/offoperation of the pump. At Influent Pump Station Service Pedestal, plant personal canselect between Hand-Off-Automatic operations via a selector switch. When the selectorswitch is in the Hand position, the pump will run at full speed. When the selector switch isin the Off position, the pump will not run and is not available for automatic or manualoperation.

d. Remote Control: When the Hand/Off/Automatic Selector Switch is in the Automaticposition, the pump operation is controlled by the ILSCP PLC.

1) SCADA/OIT Control Selection: From a SCADA Workstation or from the OIT mountedon Influent Pump Station Service Pedestal, Control Panel Section, ILSCP PLC controlcan be placed in either Remote Manual Control or Automatic Control.

2) Remote Manual Control: When Remote Manual Mode is selected at SCADA or InfluentPump Station Service Pedestal OIT, the pump shall be capable of manual control fromSCADA or IPCP OIT. The pump operations are "Start" and "Stop."

3) Automatic Control: When Automatic Control Mode is selected at SCADA or PumpStation Service Pedestal OIT, the pump operations shall be as described previouslywithin this control strategy under item 1 General.

3. Level Measurement System:

a. Submersible Level Transmitter - LIT 310

1) Function: A submersible level transmitter will monitor the level in Influent Lift StationWet Well. This level signal is monitored by ILSCP PLC. This level signal is used in theautomatic PLC based control of Influent Lift Station Pumps 1, 2, and 3 and alarms:

a) High-High Level Alarm for Influent Lift Station Wet Well

b) High Level Alarm for Influent Lift Station Wet Well

c) Low Level Alarm for Influent Lift Station Wet Well


d) Low-Low Level Alarm for Influent Lift Station Wet Well

e) Start and Stop Control of Influent Lift Station - Lead Pump

f) Start and Stop Control of Influent Lift Station - Lag Pump

g) Start and Stop Control of Influent Lift Station - Standby Pump

b. Float Type Level Switches - LSHH 320, LSH 320, LSL 320

1) Function: The level switches provide alarm status regarding the wet well level as wellas backup hardwired control of the Influent Lift Station Pumps in the event of either afailure of the PLC or the level transducer.

4. The panel enclosure shall have an entry alarm with timer and operator reset.

5. Site lighting shall operate on a photocell.

C. Control Strategy - Influent Flow Meter

1. The WWTP shall have an electromagnetic flow meter measuring flow into the plant. Flows willbe monitored by SCADA.

2. Function: A flow meter will monitor the discharge flow from the Influent Lift Pumps Wet Well.This flow signal is monitored by PCP PLC. This flow signal is used for status and alarms:

a. Influent Pump Station Instantaneous

b. High-High Influent Pump Station Discharge Flow Alarm

c. High Influent Pump Station Discharge Flow Alarm

d. Low Influent Pump Station Discharge Flow Alarm

e. Low-Low Influent Pump Station Discharge Flow Alarm

3. The following status and alarm states shall be display at SCADA and on the PCP OIT:

a. Influent Pump Station Instantaneous Flow

b. Influent Pump Station Total Flow, Non-Resettable

c. Influent Pump Station Total Flow, Resettable

d. Influent Pump Station Current Day, Daily Total Flow

e. Influent Pump Station Previous Day, Daily Total Flow

D. Control Strategy - Influent Auto-Sampler

1. General: The auto-sampler will automatically take samples from the influent flow screenproportional to the influent flow rate.

a. A PLC analog output shall provide the influent sampler flow pace signal to the influent autosampler. This signal shall be directly proportional to the influent flow and shall be operatoradjustable from 0 to 100%, initially set at 100%.

b. The PCP PLC shall monitor up to four influent auto sampler alarm conditions. These fouralarm conditions shall be reported individually to SCADA and displayed on the PCP OIT.

1) Peristaltic Pump Jammed

2) Sample Container Error

3) Flow Though Pump Failure

4) Alarm condition to be selected by engineer upon review of the automatic samplersubmittal


2. The influent auto-sampler shall run continuously

E. Control Strategy - Headworks Screen

1. General: The Headworks Screen consists of a packaged drum screen that is controlled from apackaged control panel, Headworks Screen Control Panel, CP-401. The packaged drumscreen will be equipped with a local control station containing an emergency stop push/pullbutton. The drum screen services its flow stream and removed solids that are deposited on abin.

a. The Headworks Screen Control Panel PLC (HSCP PLC) shall be programmed by theHeadworks Screen System supplier. The Headworks Screen System supplier shallcoordinate with the Control System Integrator regarding the data exchange between theHSCP PLC and the PCP PLC via the hard PLC I/O structure.

b. The Headworks Screen Control Panel will contain the following devices:

1) Power On Pilot Light

2) Screen Standby Pilot Light

3) Screen Running Pilot Light

4) Overload Shutdown Pilot Light

5) Drive Malfunction Pilot Light

6) Screen Hand-Off-Automatic Selector Switch

7) Lower Wash System Hand-Off-Automatic Selector Switch

8) Screenings Wash System Hand-Off-Automatic Selector Switch

9) I RGA Wash System Hand-Off-Automatic Selector Switch

10) Screen Forward-Off-Reverse Selector Switch

11) Overload Shutdown Pushbutton

12) Elapsed Time Meter

13) Operator Interface Panel

c. The Headworks Screen System Control Panel will have a PLC that will have the followingoutputs available for interfacing with the PCP PLC:

1) The following discrete signals shall be provided from the HSCP PLC to the PCP PLC:

a) Screen Drive Motor Running

b) Screen Control Panel Failure

c) Screen Level 1 High Alarm

d) Screen Level 1 High-High Alarm

e) Screen 1 System In Automatic

2) The following discrete signals shall be provided from the PCP PLC to the HSCP PLC:

a) None required

3) The following analog signals shall be provided from the HSCP PLC to the PCP PLC:

a) None required

4) The following analog signals shall be provided from the PCP PLC to the HSCP PLC:

a) None Required


F. Control Strategy - Bypass to Overflow Valve, FCV-401

1. General: The Headworks Screen is supplemented by a bypass line with a bypass valve thatallows raw influent to flow directly to the emergency storage pond. When the Bypass Valve isset for Automatic Control and a Headworks High-High level alarm occurs, then the BypassValve will open. Flow will divert around the Headworks Screen directly to the emergency ponduntil the level falls below the Headworks High-High level alarm. The Bypass Valve will remainin the Bypass Position until a "Bypass Valve Reset" command is issued via either SCADA orfrom the PCP OIT. Once the "Bypass Valve Reset" command is issued the Bypass Valve willreturn to the closed position and remain in that position under the next Headworks High-Highlevel alarm occurs.

a. Local Control: The bypass valve is equipped with a motorized actuator. At the actuator,plant personnel can select between manual control and remote control using theRemote/Off/Manual Selector Switch. When the selector switch is in the Manual position,the bypass valve can be driven open using the open pushbutton or driven close with theclose pushbutton. Local indicator light denote when the valve is fully open or fully closed.

b. Remote Control: When the Remote/Off/Manual Selector Switch is in the Remote position,the valve operation is controlled from by PCP PLC.

1) SCADA Control Selection: From a SCADA Workstation or the Plant Control PanelOperator Interface Terminal (PCP OIT), PCP PLC control can be placed in eitherRemote Manual Control or Automatic Control.

2) Remote Manual Control: When Remote Manual Mode is selected at SCADA or PCPOIT, the bypass valve shall be capable of manual control from SCADA. The bypassvalve operations are "Drive to fully open position" or "Drive to fully closed position".

c. Automatic Control: When Automatic Control Mode is selected at SCADA or at PCP OIT,the bypass valve operations shall be as described previously within this control strategyunder item 1 General.

G. Control Strategy - Membrane Bioreactor (MBR)

1. The membrane bioreactor shall be controlled by the manufacturer supplied Membrane ControlPanel, MBR-PLC. All control is as detailed elsewhere and is shown on the P&ID diagram. TheMBR will supply the MBR Control Panel including an Allen Bradley ControlLogix PLC and aWonderware based SCADA system. Areas controlled by the MBR-PLC include:

a. Anoxic basins and all related equipment

b. Mixed Liquor pump station and related equipment

c. Aeration Basins and related equipment

d. Membrane Basins and related equipment

e. Permeate pump station and related equipment

f. Membrane blowers and related equipment

g. Process blowers and related equipment

h. Turbidity Measurement

i. Clean-In-Place

2. The MBR PLC program and the MBR SCADA program will be developed by the MBR systemsupplier. The MBR System supplier shall provide all of the PLC and SCADA programmingnecessary to fully operate the MBR processes and in keeping with the programming guidelinesprovided in this section. The MBR Supplier shall coordinate with the System Integrator to


ensure that the MBR SCADA control and monitoring functions can be provided from either theMBR SCADA workstation or from the Plant Wide SCADA system computer workstations.

3. The System Integrator responsible for providing the PCP PLC program and the plant-wideSCADA system shall coordinate with the MBR System supplier. The System Integrator shallbe responsible of adding the MBR System supplier SCADA program to the Plantwide SCADAsystem to allow the MBR processes to be controlled and monitored from either the MBRSCADA computer or from the Plant Wide SCADA system computer workstations.

H. Control Strategy - Effluent Auto-Sampler

1. General: The auto-sampler will automatically take samples from the effluent pump stationdischarge flow screen proportional to the effluent flow rate.

a. A PLC analog output shall provide the effluent pump station discharge flow pace signal tothe effluent auto sampler. This signal shall be directly proportional to the effluent pumpstation discharge flow and shall be operator adjustable from 0 to 100%, initially set at100%.

b. The PCP PLC shall monitor up to four influent auto sampler alarm conditions. These fouralarm conditions shall be reported individually to SCADA and displayed on the PCP OIT.

1) Peristaltic Pump Jammed

2) Sample Container Error

3) Flow Though Pump Failure

4) Alarm condition to be selected by engineer upon review of the automatic samplersubmittal

I. Control Strategy - Effluent Storage Tank

1. General: The Effluent Storage Tanks will have two level measurement systems.

a. Ultrasonic Level Transmitter - LE/LT 600

1) Function: An ultrasonic level transmitter will monitor the level in Effluent Storage Tank.This level signal is monitored directly by the PCP PLC and the MBR PLC. This levelsignal is used in the automatic PLC based control of Permeate Pump 1 and 2 by theMBR PLC. This level signal is used for the automatic PLC based control of EffluentPumps 1, 2, and 3 alarms:

a) High-High Level Alarm for Effluent Storage Tank (PCP PLC program)

b) High Level Alarm for Effluent Storage Tank (PCP PLC program)

c) Low Level Alarm for Effluent Storage Tank (PCP PLC program)

d) Low-Low Level Alarm for Effluent Storage Tank (PCP PLC program)

e) Effluent Pump Station Ready for Pumping Level (PCP PLC program)

f) Start and Stop Control of Effluent Pump Station (PCP PLC program)

g) Start and Stop Control of the Permeate Pumps 1 and 2 (MBR PLC program)

2) The Effluent Storage Tank Level shall be displayed on SCADA and the PCP OIT.

3) The Effluent Storage Tank Level Set points associated with the PCP PLC programshall be adjustable from SCADA or the PCP OIT.

4) The Effluent Storage Tank Level Alarms shall be displayed on SCADA and the PCPOIT.

b. Float Type Level Switches - LSHH 600, LSLL 600Indian Health Services Tule River Community Wastewater SystemAugust 2010 Control Strategies261-004-100 17924-14

1) Function: The level switches provide alarm status regarding the Effluent Storage Tank

to SCADA and the PCP OIT via PCP PLC.

a) LSHH 600 is monitored directly by the PCP PLC and the MBR PLC.

b) For the PCP PLC, if the level in the Effluent Storage Tank falls below LSLL 600then the Effluent Pumps will suspend pumping operations until the Effluent StorageTank level rises to the Effluent Storage Tank Level Ready for Effluent PumpingOperations Set point,

c) For the MBR PLC, if the level in the Effluent Storage Tank rises to LSHH 600 thenthe Permeate Pumps will suspend pumping operations until the Effluent StorageTank level falls to the Effluent Storage Tank Level Ready for Permeate PumpingOperations Set point.

J. Control Strategy - Effluent Pump Station

1. General: The Effluent Pump Station flow from the Effluent Storage Tank. The Effluent PumpStation controls the flow steam to the Effluent Disposal Area. The Effluent Pump Stationconsists of four centrifugal pumps that operate in a lead, lagi, lag2 and standby manner withautomatic alternation. Each of the four pumps is equipped with a variable frequency drive thatallows the pumps to vary their speed.

a. The Effluent Pump Station is equipped with a pressure transmitter on the discharge line,the pumps will operate to maintain a discharge pressure set point with the PCP PLCcontrolling the pump speed and selecting the number of pump required in an energyefficient manner.

b. The Effluent Pump Station is equipped with two pressure switches - a low pressure switchon the suction header of the Effluent Pump Station and a high pressure switch on thedischarge header of the Effluent Pump Station. If either condition occurs, an alarm shall beissued to SCADA and displayed on the PCP OIT.

c. Automatic and remote control for each pump is provided by the PCP PLC. Normalautomatic operation is to allow the Effluent Pumps to operate in a lead/lagl/lag2/standbyconfiguration to maintain a discharge pressure set point. Effluent Pump Station pumpingoperations will be controlled by the PCP PLC as described below:

1) When the Effluent Pumps are set for automatic, the Effluent Pumps No. 1, No. 2, No. 3and No. 4 will operate in a lead/lagl/lag2/standby manner with automatic alternation ofthe pumps. The purpose of the automatic alternation scheme shall be to equalize theruntime of each of the four pumps. Automatic alternation shall designate the pump withthe shortest runtime, as the lead pump, the next shortest as Lag 1, etc.

2) Provide manual override of the automatic alternator at SCADA and the PCP OIT thatallows plant personnel to designate the "Lead Pump", "Lagi Pump", "Lag 2 Pump" and"Standby Pump". When manual override is active, the pumps will alternate in this fixedsequence until placed back to automatic alternation. For example, when two pumpsare selected for automatic control, the manual override will allow a plant operator tochoose Lead/Lagi with Alternation scheme and when three pumps are selected forautomatic control, the manual override will allow a plant operator to chooseLead/Lag 1/Lag2 with Alternation scheme.

3) If only one pump has its Hand/Off/Automatic Selector Switch in the "Automatic"position, then that pump will operate as the lead pump.

4) If only two pumps have their Hand/Off/Automatic Selector Switches in the "Automatic"position, then those two pumps will operate in a lead/lag manner with automaticalternation.


5) When the Effluent Discharge Pressure falls to the "Start Effluent Pump StationDischarge Pressure" set point, then the lead pump will start at minimum speed andramp up to the "Desired Discharge Pressure" set point. The lead pump speed will rampup and down as required to meet the "Desired Discharge Pressure" set point. If thelead pump is running at maximum speed, cannot meet the "Desired DischargePressure" set point and the "Add a pump time delay" has timed out, then the lag 1pump will start. The lead and lag 1 pump will be controlled in unison to ramp up anddown to meet the "Desired Discharge Pressure" set point. If the running pumps arerunning at minimum speed, the "Desired Discharge Pressure" set point is satisfied, andthe "Stop a pump time delay" has timed out, then lag 1 pump will shut down and thelead pump will continue to operate to maintain the "Desired Pressure" Set point. Thelag 2 pump will then be brought on or off in a similar matter if additional pumping is stillrequired.

6) If the lead pump, lag 1 pump, or lag 2 pump fails, then the Standby Pump will start andoperate in its place.

d. The following control set points shall be provided:

1) Low Discharge Pressure Alarm

2) High Discharge Pressure Alarm

3) Start Effluent Pump Station Discharge Pressure

4) Desired Discharge Pressure for Pumping

5) Add a pump time delay

6) Stop a pump time delay

7) Pump Control Loop Tuning Constants - One Pump Operation

8) Pump Control Loop Tuning Constants - Two Pump Operation

9) Pump Control Loop Tuning Constants - Three Pump Operation

e. Provide at SCADA and the OIT, pressure alarms based on the pressure transmitter andthe pressure switches.

f. If all the enabled pumps are running but the "Desired Discharge Pressure" set point cannot be maintained, then an alarm generated at the PCP PLC, displayed on the PCP PLCand reported to SCADA.

2. Effluent Pump No. 1 (P-611):

a. Typical of Effluent Pump No. 2 (P-612), Effluent Pump No. 3 (P-613), and Effluent PumpNo. 4 (P-614).

b. Function: Effluent Pump No. 1 is one of four pumps that will control the flow out of theEffluent Storage Tank to maintain a system discharge pressure to the Disposal Areas. Thepump is equipped with a variable frequency drive to allow variable speed control of thepump.

c. Local Control: At the Motor Control Center in the Operations Building, plant personal canselect between Hand-Off-Automatic operations via a selector switch. When the selectorswitch is in the Hand position, the pump speed control is set using the VFD OperationInterface Panel. When the selector switch is in the Off position, the pump will not run and isnot available for automatic or manual operation. At the motor, a lock-out-stop station isprovided for shutting down the pump.


d. Remote Control: When the Hand/Off/Automatic Selector Switch is in the Automaticposition, the pump operation is controlled by the PCP PLC.

1) SCADA!OIT Control Selection: From a SCADA Workstation or from the OIT mountedon Influent Pump Station Service Pedestal, Control Panel Section, PCP PLC controlcan be placed in either Remote Manual Control or Automatic Control.

2) Remote Manual Control: When Remote Manual Mode is selected at SCADA or InfluentPCP OIT, the pump shall be capable of manual control from SCADA or PCP OIT. Thepump operations are "Start," "Stop," and "Manual Speed Control".

3) Automatic Control: When Automatic Control Mode is selected at SCADA or PumpStation Service Pedestal OIT, the pump operations shall be as described previouslywithin this control strategy under item 1 General.

e. Variable Speed Control Features: The following set points shall be used as part theautomatic control strategies and shall be accessible via SCADA:

1) Pump Minimum Speed

2) Pump Maximum Speed

3) One Pump Running, Speed Control Tuning Constants

4) Two Pumps Running, Speed Control Tuning Constants

5) Three Pump Running, Speed Control Tuning Constants

K. Control Strategy - Effluent Flow Meter

1. The WWTP shall have a site standard electromagnetic flow meter measuring flow from theEffluent Pump Station to the Disposal Areas. Flows will be monitored by SCADA.

2. Function: A flow meter will monitor the discharge flow from the Effluent Pump Station. Thisflow signal is monitored by PCP PLC. This flow signal is used for status and alarms:

a. Effluent Pump Station Instantaneous

b. High-High Effluent Pump Station Discharge Flow Alarm

c. High Effluent Pump Station Discharge Flow Alarm

d. Low Effluent Pump Station Discharge Flow Alarm

e. Low-Low Effluent Pump Station Discharge Flow Alarm

3. The following status and alarm states shall be display at SCADA and on the PCP OIT:

a. Effluent Pump Station Instantaneous Flow

b. Effluent Pump Station Total Flow, Non-Resettable

c. Effluent Pump Station Total Flow, Resettable

d. Effluent Pump Station Current Day, Daily Total Flow

e. Effluent Pump Station Previous Day, Daily Total Flow

L. Control Strategy - Effluent Disposal Fields

1. General: The effluent pump station discharge flow is sent to the effluent disposal fields. Flowto the disposal fields are controlled by a series of solenoid operated valves that control flow toeach effluent disposal field and also to the individual sections that make up each effluentdisposal field. There are nine separate Effluent Disposal Fields with each field divided into twoto five sections. Each of the Effluent Disposal Fields shall operate independently of the other


Effluent Disposal Fields. Each of the Effluent Disposal Fields is equipped with a flow meterthat monitors the effluent flow sent to that Effluent Disposal Field.

a. In automatic mode, the plant effluent will be distributed each of the effluent disposal fieldsthat are selected for automatic operations. The plant effluent is sequentially distributed toeach of the Effluent Disposal Field in an order predetermined by plant staff. Within eacheffluent disposal field, the plant effluent is sequentially distributed to the sections that makeup that effluent disposal field. The flow to each section shall be time based, operatoradjustable. When the sections of an effluent disposal field have all been served, the planteffluent will then be distributed to the next selected effluent disposal field. Once an effluentdisposal field has been served, flow cannot be sent to that effluent disposal field until it hasbeen allowed to "rest". Plant staff will determine how long this rest period will be and thistime interval shall be adjustable via SCADA.

b. Automatic Effluent Disposal Operations shall start and stop in conjunction with the effluentpump station pumping operations. If the Effluent Pump Station Discharge Flow Meter(FE/FIT 612) indicates flow, then after a time delay, the Automatic Effluent Disposal FieldSchedule is implemented. If the Effluent Pump Station Discharge Flow Meter (FE/FIT 612)indicates no flow, then after a time delay, the Automatic Effluent Disposal Field Schedule issuspended until flow resumes. When flow resumes the schedule shall pick up from the lastpoint in the schedule not restart from the beginning.

c. Automatic Effluent Disposal Field Schedule: This schedule shall control the operations ofall of the Effluent Disposal Field Control Valves and all of the Effluent Disposal FieldSection Control Valve that are set for automatic operation. Provide a separate summer andwinter schedule that is selectable via SCADA or the PCP OIT. The Schedule shall have thefollowing features:

1) List all of the Effluent Disposal Fields

a) List the Automatic/Off/Manual Mode for each Effluent Disposal Field

b) List all of the Section Valves per Effluent Disposal Field

(i) List the Automatic/Off/Manual Mode for each Section Valve, operator adjustablein schedule

(ii) List the Open Time Intervals for each Section Valve, operator adjustable inschedule

2) List the Rest Interval for each Effluent Disposal Field, operator adjustable in schedule.Once all of the selected sections of a Effluent Disposal Field have been serviced, thenthe Rest Interval must complete before that Effluent Disposal Field can be servedagain with Effluent.

3) List the Selected Order that the Effluent Disposal Fields will be services, operatoradjustable in schedule.

4) Highlight or indicate which Effluent Disposal Field and which section valve is currentlyopen. Indicate the time remaining for that step.

d. Via SCADA or the PCP OIT, plant staff can set each effluent disposal field to operateautomatically, manually or place out-of-service (e.g., off).

e. Via SCADA or the PCP OIT, plant staff can set any section of an effluent disposal field tooperated automatically, manually, or place a section out-of-service (e.g. off).

f. Via SCADA or the PCP OIT, plant staff can set the time duration that an effluent disposalfield section control valve will be open during an automatic disposal operation. The effluent


disposal field control valve shall open and close as necessary to satisfy the total timeduration set for all of the section valves associated with that effluent disposal field.

g. Via SCADA or the PCP OIT, plant staff can set the order that the effluent disposal fieldswill be utilized during an automatic disposal operation.

h. If a flow disposal field flow meter detects flow when the associated disposal field controlvalve and associated section control valves have not been place in open via automatic ormanual means, a Disposal Field Alarm shall be issued to SCADA.

i. On the SCADA and PCP OIT Screen displays which Effluent Disposal Field is in use,which section is being served, and the time remaining for that effluent disposal fieldsection.

j. Rainy Day Multiplier: Via SCADA and PCP OIT provide a set point scaled from 0 to 100%that automatically adjusts all of the effluent disposal field section valve open time durationsby this factor when an automatic effluent disposal field operation is.

1) Via SCADA and PCP OIT provide an enable/disable Rainy Day Multiplier controlfeature.

2) When enabled, display the Rainy Day Multiplier on the SCADA and PCP ScreenDisplays.

k. During an automatic effluent disposal field operation, the valves shall be operation in amanner that minimizes surging. For example, when the PLC calls for Effluent DisposalField A Section 1 Control Valve to open, the Effluent Disposal Field A Control Valve (SVAl 0) will first open and after a time delay Effluent Disposal Field A Section 1 Control Valve(SV All) will open. When the automatic effluent disposal field A Section 1 Open TimeInterval is complete, the Effluent Disposal Field A Section 1 Control Valve (SV All) willclose and after a time delay then the Effluent Disposal Field A Control Valve (SV Al0) willclose.

I. The Automatic Effluent Disposal Operations Schedule shall be completed even if theeffluent pump station starts and stops before completing the schedule.

m. If the Effluent Pump Station remains running longer that the duration of the AutomaticEffluent Disposal Operations Schedule, then the schedule will continue to repeat asrequired.

n. Via SCADA or the PCP OIT, plant staff can reset the Automatic Effluent DisposalOperation Schedule during Effluent Pump Station pumping operations.

o. On SCADA and the PCP OIT, display the number of times that the Automatic EffluentDisposal Operation Schedule is completed during the current day, and the previous day.

2. Effluent Disposal Field A Control Valve (SV A10):

a. Typical of Effluent Disposal Field B Control Valve (SV B10), Effluent Disposal C ControlValve (SV C10), Effluent Disposal Field D Control Valve (SV D10), Effluent Disposal FieldE Control Valve (SV El0), Effluent Disposal Field F Control Valve (SV F10)Effluent Disposal Field G Control Valve (SV G10), Effluent Disposal Field H Control Valve(SV H10), and Effluent Disposal Field I Control Valve (SV 110).

b. Function: Effluent Disposal Field A Control Valve (SV A10) controls the flow to EffluentDisposal Field A. When the valve is set for automatic operation the valve will open andclose based on the automatic strategy describe previously within this control strategyunder Item 1 General. When manual valve operation is selected at SCADA or the PCPOIT, then plant staff can place the valve in the open or close position. The valve will remainin the position selected regardless of the automatic operations associated with any other


Effluent Disposal Field. The following control actions shall be available via SCADA or the

PCP OIT:

1) Effluent Disposal Field A Control Valve set to automatic.

2) Effluent Disposal Field A Control Valve set to off.

a) Valve is not available for manual or automatic operations.

3) Effluent Disposal Field A Control Valve set to manual

a) Manual Open Command to Valve

b) Manual Close Command to Valve

3. Effluent Disposal Field A Section 1 Control Valve (SV Al 1):

a. Typical of Effluent Disposal Field A Section 2 Control Valve (SV A12), Section 3 ControlValve (SV A13), and Section 4 Control Valve (SV A14); Effluent Disposal Field B Section 1Control Valve (SV Bll), Section 2 Control Valve (SV B12), and Section 3 Control Valve(SV B13 Section 4 Control Valve (SV B14); Effluent Disposal Field C Section 1 ControlValve (SV Cll), Section 2 Control Valve (SV C12), Section 3 Control Valve (SV C13),Section 4 Control Valve (SV C14), and Section 5 Control Valve (SV Ci5); Effluent DisposalField D Section 1 Control Valve (SV Dli), Section 2 Control Valve (SV D12), Section 3Control Valve (SV D13), and Section 4 Control Valve (SV D14); Effluent Disposal Field ESection 1 Control Valve (SV Ell), Section 2 Control Valve (SV E12), and Section 3Control Valve (SV E13); Effluent Disposal Field F Section 1 Control Valve (SV FIll)and Section 2 Control Valve (SV F12); Effluent Disposal Field G Section 1 Control Valve(SV Gll), Section 2 Control Valve (SV G12), and Section 3 Control Valve (SV G13);Effluent Disposal Field H Section 1 Control Valve (SV Hll), Section 2 Control Valve (SVH12), and Section 3 Control Valve (SV H13); and Effluent Disposal Field I Section 1Control Valve (SV I11), Section 2 Control Valve (SV 112), Section 3 Control Valve (SV 113),and Section 4 Control Valve (SV 114).

b. Function: Effluent Disposal Field A Section 1 Control Valve (SV All) controls the flow toSection 1 of the Effluent Disposal Field A. When the valve is set for automatic operationthe valve will open and close based on the automatic strategy describe previously withinthis control strategy under Item 1 General. When manual valve operation is selected atSCADA or the PCP OIT, then plant staff can place the valve in the open or close position.The valve will remain in the position selected regardless of the automatic operationsassociated with any other Effluent Disposal Field. The following control actions shall beavailable via SCADA or the PCP OIT:

1) Effluent Disposal Field A Section 1 Control Valve set to automatic.

2) Effluent Disposal Field A Section 1 Control Valve set to off.

a) Valve is not available for manual or automatic operations.

3) Effluent Disposal Field A Section 1 Control Valve set to manual

a) Manual Open Command to Valve

b) Manual Close Command to Valve

4) Automatic Effluent Disposal Section Valve Open Time Duration (Selectable in Hoursand Minutes)

4. Effluent Disposal Field A Flow Meter (FE/FIT A10):

a. Typical of Effluent Disposal Field B Flow Meter (FE/FIT B10), Effluent Disposal Field CFlow Meter (FE/FIT C10), Effluent Disposal Field D Flow Meter (FE/FIT D10), Effluent


Disposal Field E Flow Meter (FE/FIT El0), Effluent Disposal Field F Flow Meter (FE/FITF10), Effluent Disposal Field G Flow Meter (FE/FIT G10), Effluent Disposal Field H FlowMeter (FE/FIT H10), Effluent Disposal Field I Flow Meter (FE/FIT 110).

b. Function: Effluent Disposal Field A Flow Meter will monitor the flow into Effluent DisposalField A. This flow signal is used for status and alarm:

1) Effluent Disposal Field A Instantaneous Flow

2) Effluent Disposal Field A Total Flow, Non-Resettable

3) Effluent Disposal Field A Total Flow, Resettable

4) Effluent Disposal Field A, Current Day, Daily Total Flow

5) Effluent Disposal Field A, Previous Day, Daily Total Flow

6) Effluent Disposal Field A, Section 1:

a) Typical of Effluent Field A - Section 2, Section 3, and Section 4

b) Effluent Disposal Field A has four sections. Each section has a Section ControlValve that allows flow to that action. Each Section of the Disposal shall have thefollowing flow status and alarms:

(i) Effluent Disposal Field A, Section 1 Total Flow, Non-Resettable

(ii) Effluent Disposal Field A, Section 1 Total Flow, Resettable

(iii) Effluent Disposal Field A, Section 1, Current Day, Daily Total Flow

(iv) Effluent Disposal Field A, Section 1, Previous Day, Daily Total Flow

M. Control Strategy - Solids Handling

1. WAS Pump Station

a. General: The waste activated sludge (WAS) Pump Station shall be used to waste mixedliquor from the membrane basins. The pumping source shall be selected by the manualoperation of valves at the membrane basins. The WAS Pump Station consists of a singlepump and is controlled by a Variable Frequency Drive. PLC based control operations shallallow the pump to be controlled from a local control station adjacent to the pump. The localcontrol station shall provide plant staff with both manual and automatic control operations.

1) The WAS pump station is equipped with a WAS Pump Station Discharge Flow Meterand will be used to control the automatic PLC based WAS pump operations.

2) The WAS pump station is equipped with a local control station that consists of a Hand-Off-Automatic Selector Switch, Speed Indicator, and Speed Setpoint Station.

3) The WAS Pump Station Pumping Total Flow Set Point shall be operator adjustable atSCADA or at the PCP OIT.

4) Automatic and remote control for the WAS Pump is provided by the PCP PLC. Normalautomatic operation is to allow the WAS pump to immediately start pumping at theselected pump speed until the WAS Pumping Total Flow Set Point is met. Once theWAS Pumping Total Flow Set Point is met, the WAS pump will stop. The pump willremained stopped until the local Hand-Off-Automatic Selector Switch is placed back tothe Off position. To begin another automatic pump cycle, the local Hand-Off-AutomaticSelector Switch shall be placed back to the Automatic Position and then the pumpcycle can repeat.

5) If the local Hand-Off-Automatic Selector Switch is placed in the Hand position, then theWAS pump shall run continuously at the speed set at the local speed set point station.


The pump will continue to run until the local Hand-Off-Automatic Selector Switch is

placed in the Off position.

b. WAS Pump (P-710):

1) Function: WAS Pump controls the WAS flow from a manually selected MBR Basins.The pump is equipped with a variable frequency drive to allow variable speed control ofthe pump.

2) Local Control: At the Motor Control Center in the Operations Building, plant personalcan select between Hand-Off-Remote operations via a selector switch. When theselector switch is in the Hand position, the pump speed control is set using the VFDOperation Interface Panel. When the selector switch is in the Off position, the pump willnot run and is not available for automatic or manual operation.

3) Remote Control: When the Motor Control Center Hand/Off/Remote Selector Switch isin the Remote position, the pump operation is controlled by the PCP PLC.

4) A local control station adjacent to the pump has a Hand-Off-Automatic Selector Switch,WAS Pump Speed Display and a WAS Pump Speed Setpoint Station. The operationsassociated with the local control station are described previously within this controlstation under Item 1, a General. ral.

5) Variable Speed Control Features: The following set points shall be used as part theautomatic control strategies and shall be accessible via SCADA:

a) Total WAS Flow Setpoint.

c. WAS Flow Meter (FE/FIT 710)

1) The WWTP shall have a site standard electromagnetic flow meter measuring dischargeflow from the WAS Pump Station. Flow will be monitored by SCADA.

2) Function: A flow meter will monitor the discharge flow from the WAS Pump Station.This flow signal is monitored by PCP PLC. This flow signal is used for status andalarms:

a) WAS Pump Station Instantaneous

b) High-High WAS Pump Station Discharge Flow Alarm

c) High WAS Pump Station Discharge Flow Alarm

d) Low WAS Pump Station Discharge Flow Alarm

e) Low-Low WAS Pump Station Discharge Flow Alarm

f) The following status and alarm states shall be display at SCADA and on the PCPOIT:

(i) WAS Pump Station Instantaneous Flow

(ii) WAS Pump Station Total Flow, Non-Resettable

(iii) WAS Pump Station Total Flow, Resettable

(iv) WAS Pump Station Current Day, Daily Total Flow

(v) WAS Pump Station Previous Day, Daily Total Flow

2. Polymer Feed System

a. General: The polymer feed system is a packaged system consisting of a polymer blendingcontrol panel, polymer feed pump, polymer tank, valves, mixer, pressure switch, pressureindicator and other required accessories.


b. The polymer feed system will start and stop in conjunction with the WAS pump operations.

c. The following control commands shall be issued via the PCP PLC:

1) Start/Stop the polymer feed system based on the start/stop of the WAS Pump.

2) Flow pace signal for polymer blend speed control based on the WAS Flow Meter.

d. The following status and alarm signals shall be sent to the PCP PLC.

1) Polymer Blend System Running

2) Polymer Blend System Running

e. The polymer blending control panel shall control the all of the process operationsassociated with the polymer blend system including but not limited to the following:

1) The feed rate and concentration shall be controlled at the polymer blending unit.

2) Upon pumping an operator selectable WAS flow total, following locally initialized flow,operation of both the WAS pump and polymer skid shall cease.

N. Control Strategy - Power and Security

1. The SCADA system shall monitor the status of the emergency standby generator and the fueltank as indicated on the P&IDs.

2. The SCADA system shall monitor the various alarm status conditions:

a. UPS power failure at each UPS unit.

b. Control Power AC Failure at each Control Panel

c. Utility Service Failure at the Plant Control Panel, and the Well Service Pedestals

d. Intrusion alarm at each control panel or service pedestal.

3. The PCP PLC shall monitor the standby generator run status. In the event of a power outagethe PCP PLC shall provide for a bumpless control transfer to the emergency standbygenerator. Provide a controlled sequence that allows for restarting of all the processoperations controlled by the PCP PLC.

**END OF SECTION**


section 17924 control strategies - eandm

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