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FUNCTIONAL SPECIFICATION SECTION D

SWITCHBOARD AND SCADA INSTALLATION AT NYNGAN WTP CONTRACT NO: 2016/4/SWITCH BOARD AND SCADA

Engineering Department 5/09/2016

Bogan Shire Council

SWITCHBOARD AND SCADA

INSTALLATION AT NYGAN

WTP

Functional Specification

Issue for Tender

June 2012

Presented by Hunter H2O Pty Limited

ABN 16 602 201 552

Bogan Shire Council A.B.N. 68 886 242 083 i Functional Specification

SWITCHBOARD AND SCADA INSTALLATION AT NYNGAN WTP 2016/4/Switch Board and SCADA

Report Details

Report Title Switchboard and SCADA installation at nygan wtp: Functional Specification

Project No. 3591

Status Issue for Tender

File Location

P:\Bogan Shire Council\4540 - Switchboard Replacement Principals Rep\2. Tasks\1. Task 1-Process Input\Functional Specification\4540_Nyngan WTP FSpec Short_REVB.docx

Document History and Status

Revision Report Status Prepared by Reviewed by Approved by Issue Date

Issued for tender

REV C Peter Greenhalgh

Rick Barry David Longmuir 19/08/16

Copyright © Hunter H2O Pty Limited 2016 The concepts and information contained in this document are the property of Hunter H2O Pty Limited for the sole use of the nominated client. Use or copying of this document without the written permission of Hunter H2O constitutes an infringement of copyright. Enquiries to: Peter Greenhalgh P: (02) 4941 4922

Position F: (02) 4941 5011

Hunter H2O E: [email protected]

Bogan Shire Council A.B.N. 68 886 242 083 ii Functional Specification


Contents 1 Introduction 3

2 Automation and Control Overview 4

2.1 Definitions, Acronyms and Abbreviations 4

2.2 Electrical Requirements 4

2.3 Control System Overview 5

2.4 Automatic Control Philosophy 7

2.5 Plant Power Supply, Switchboard and Auxiliaries 13

2.6 PLC and Telemetry Systems 14

3 Process Control Philosophy 16

3.1 WTP Control 16

3.2 Clarification and Sedimentation 21

3.3 Filtration 25

3.4 Clear Water Storage & Transfer 29

3.5 Alum and Soda Ash Dosing Systems 32

Bogan Shire Council A.B.N. 68 886 242 083 3 Functional Specification


1 Introduction This Functional Specification specifies the operational, control and alarm requirements for the Nyngan Water Treatment Plant (WTP).

This Functional Specification shall be used in conjunction with the process and instrumentation drawings, electrical drawings, PLC Controller Technical Specification, SCADA Technical Specification and other relevant parts of the contract to develop the PLC control code and SCADA/HMI interfaces.

Note: Not all items of equipment and instruments may be in place at the time of implementing this code. The validity of each portion of the functional specification must be reviewed to determine if it can be successfully implemented. If a portion of the code relies on equipment or instruments which are not in place, that portion of the code must not be programmed and the absence of its implementation noted in a detailed summary. The contractor is required to ensure that where there is a discrepancy between the instruments and equipment’s provided and that described in this document, full functionality of all equipment is provided.

The contractor is responsible for updating the functional specification based on any changes deemed necessary to provide a fully functional WTP. This includes the development of set points and instrument ranges which shall be developed in conjunction with BSC to ensure the requirements of the Nyngan WTP Drinking Water Quality Management Plan (DWQMP). This will allow BSC to update the DWQMP including control points.



2 Automation and Control Overview

2.1 Definitions, Acronyms and Abbreviations

PLC Programmable Logic Controller

PID Proportional, Integral, Differential

I/O Input / Output

SCADA Supervisory Control and Data Acquisition

HMI Human Machine Interface

SFD Software Functional Description

2.2 Electrical Requirements

2.2.1 Plant Electrical Requirements

Since the intention is to limit the upgrade of the new MCC to the installation of a new PLC, all the plant electrical specifications are defined by the existing installation.

2.2.2 Electrical Drive Requirements

Drives on the plant are of four electrical-starting types:

Direct starters have a starter in their respective switchboard. These drives operate at a single speed only, i.e. on-off;

Variable Speed Drive (VSD) starters have a variable frequency inverter mounted in the respective switchboard. These drives can be adjusted (within limits) to operate at different speeds and to have slow start-up and shutdown. The variable speed drives parameters are set at commissioning and if adjustment is required accessed will be via the switchboard;

Soft-starters have a basic reduced voltage starter which allows the drive to start and stop slowly, but provides no other control when running. The soft-starter parameters are set at commissioning;

On-board starters are direct starters locally mounted to the drive, e.g. compressors, some small pumps and packaged equipment.

The switchboard will have for each drive a door-mounted Auto/Off/Manual selector switch providing the following functionality:

In AUTO position the drive is controlled via the PLC.

In OFF position the drive cannot operate at all.

In Manual position the drive will run via the MCC start / Stop buttons and provided protection and safety electrical interlocks are healthy.

The switchboard compartment door includes a number of indicating lamps. These lamps can indicate a number of different conditions depending upon the configuration of the drive:

Drive Fault

Drive Run

Each drive and actuated valve can be operated automatically or manually at the SCADA.



2.2.3 Uninterruptible Power Supply (UPS)

An Uninterruptable Power Supply (UPS) will be provided. Without plant mains supply it shall maintain power to the PLC equipment, instrumentation, Ethernet communications equipment, and telemetry equipment. It shall have capacity for 20 minutes, at which point the UPS will perform a controlled shutdown of the SCADA Server via the configuration software. The following UPS device outputs shall be available to the PLC:

Battery Low

Mains Fail

Fault

Bypass

2.2.4 Operation under Emergency Power

A small scale battery backup is available for the plant RTU and radio communications.

2.2.5 Requirement on PLC Failure or Power Failure

In the event of a PLC or Power failure all operating equipment stops.

On restoration of power or PLC all process sequences will be enabled for automatic operation where available, however some drives / sequences may be required to be reset due to the failure.

Power or PLC failure causes an alarm to be notified on the SCADA.

2.3 Control System Overview

2.3.1 PLC System

A Schneider PLC contains the control program for the automatic sequencing and monitoring of the plant and acts as a communications link between the Plant SCADA system and the mechanical equipment at the plant.

The PLC receives inputs from field equipment (e.g. pumps) and monitoring instruments (e.g. water level) and passes this information to the Plant SCADA system. The status of equipment can be viewed on a mimic screens.

Digital (on-off) signals are sent from the field equipment to the PLC and are processed to simulate conventional relay, timer and sequence controllers.

Control algorithms and auxiliary functions which form part of the PLC programming language process these signals in accordance with the PLC program and provide output either back to the equipment from which the signal originated, to other equipment in the field or for display on the Plant SCADA system.

Elements within the programming language include:

basic logic elements (AND, OR, NOT, EXCLUSIVE OR etc.)

memory elements (latches, timers, counters, etc.)

sequencing elements.

The PLC also retains internal logic variables such as controller status, totaliser counts and system status that can be used to modify the automatic control sequences when required (e.g. change over duty status of pumps on hours run/number of starts).

The PLC can receive and process inputs from analogue devices (e.g. instantaneous flow from a flow meter) which the PLC converts to represent process variables.

The PLC system is programmed using Unity PLC programming software.



The PLC is physically located in the new MCC cabinet in the plant switchroom.

2.3.2 SCADA & HMI Systems

2.3.2.1 Plant SCADA System

A Control Microsystems ClearSCADA will be used as the Plant SCADA system. The SCADA will integrate the functions of the works, via the PLC hardware, and provides a visual schematic representation of the operation of the plant through a series of control screen mimics, where the operator may view, monitor and control the plant.

The mimic displays will be generally based on the process and instrument diagrams and will include plant and drive status information (i.e. Drive running, stopped, faulted, valve opened, closed, modulation, etc.) required for monitoring the plant. The Plant SCADA system will also have the ability to control the plant and equipment, including but not limited, to start and stop of all motor drives, open and close of all actuated valves, making adjustments to set points and process variables, acknowledging and resetting alarms.

The SCADA system will be based on the LMWUA SCADA templates.

2.3.2.2 SCADA Control Pages

The Plant SCADA system shall provide control, indication, and alarming for the complete plant PLC, control and communication systems. The extent of display/control screens shall include the following as a minimum:

Main Menu

Plant Overview

Section overviews

Alarm Pages

Other Screens as described or required in this document.

Each drive and instrument will have an associated drive “pop up” mimic to allow drive information to be displayed and to allow the drive to be controlled on the SCADA.

2.3.2.3 SCADA Alarm Pages

Each item of equipment shall have alarms associated with its status. The alarms are to be displayed on the alarm page / banner. All alarms are to have an assigned priority depending on the severity of the alarm. Alarms shall be displayed in order of priority on the alarm page. Each alarm shall have a priority assigned to it.

Each alarm shall be time and date stamped and requires acknowledgment from the operator to be reset.

An alarm acknowledgement from the operator shall only clear the alarm if the cause of the alarm is no longer present.

Each alarm shall also have associated action text. The action text shall advise the operator of the appropriate course of action in the event of the alarm occurring.

Each critical alarm shall include a page link to allow the operator to quickly navigate to the appropriate page.

2.3.2.4 SCADA Access

Plant SCADA access will be via an individual user login and password. Each user will be allocated to a system group. Systems groups will have a related system privilege that allows the functions of the system group to be performed. There will be the following system groups:



2.3.2.4.1 Administrator

Members of the Administrator group have full access to the complete SCADA system.

2.3.2.4.2 Developer

Members of the Developer group will allow access to all functions other than security related functions on the system.

2.3.2.4.3 Operator

Members of the Operator group will be access the control system for normal day-to-day operation of the plant. This will include monitoring and control of all equipment, adjustment of all set-points and acknowledge and reset alarms. Members of the Operator group will also be able to adjust parameters related to PID Tuning and other critical setpoints.

2.3.2.4.4 View Only

This is the default access. Members of the View Only group may access the SCADA and view normal day-to-day operation of the plant. However they will not be able to control equipment, adjust setpoints, acknowledge or reset alarms.

2.3.2.5 Plant SCADA History

Unless noted otherwise elsewhere in this document, all the following points have history enabled on the plant SCADA:

All analogue points (flow, level, DO, speed, modulating valve position)

All PID Controller setting (PV, SP, Output, Proportional, Integral, Derivative)

The status of all drives (running/stopped)

The position of valves with limit switches (open/closed)

All calculated values displayed on the SCADA

2.3.3 Tag and Loop Numbers

Every piece of equipment on the plant has a unique tag number, which is based on the P&ID equipment number. This tag number is to be used in the development of the electrical drawings, PLC logic and the SCADA system.

2.4 Automatic Control Philosophy

2.4.1 Automatic Sequence Control

There are two main modes of control at the plant, those being "Auto" and "Manu". The default operation mode is "System".

The operator is able to exercise direct control of parts for the process in two ways:

Operator Interface Control from the SCADA

MCC Cell drive control

For each drive or machinery item the following monitoring contacts are typically provided in the respective MCC module:



The PLC continuously monitors contacts provided in the MCC for each drive irrespective of the control mode (‘SYSTEM’, ‘OFF’ or ‘FIELD’) selected and irrespective of whether the item is running or not and provides the following monitoring functions at all times:

Current status of each item (failed, opened, closed, etc.)

Assessment of individual and group alarms for display on SCADA

Fault discrepancy monitoring as described below.

A sequence consists of a group of one or more inter-related drives or machinery items which together carry out a particular process. Automatic sequence control logic is provided in the PLC program to control and monitor each sequence. The automatic sequence logic:

controls and monitors the ordered start up or shutdown of each item in the sequence in accordance with a predefined program and subject to designated process and time requirements;

whilst the sequence is running, continues to monitor each item and provide start/stop control, open/close control for individual items in accordance with predefined process and time requirements.

A sequence does not start until the respective automatic sequence logic is initiated by the PLC or manually from the SCADA terminal. Once initiated and prior to starting any item in the sequence, the auto sequence logic first checks that:

All drives in the process sequence are currently selected to ‘SYSTEM’ and are healthy;

The duty selection of each item is valid.

Should either of these conditions not be met, the relevant alarm indication is displayed on the SCADA and the sequence start up is aborted.

The PLC software provides fault discrepancy logic (FDL) for each valve, drive or machinery item. Fault discrepancy logic dictates that when an item of equipment is called to start, stop, open, close as applicable, a discrepancy timer will start.

If after the discrepancy timer expires the control command is not carried out, the PLC outputs a ‘FAILED’ signal to the SCADA, otherwise the timer resets.

2.4.2 Drive Status Description

Motor starters each have a selector switch and can be changed to either SYSTEM, OFF, or FIELD. It is normal practice when the pump is serviceable and enabled, for the local selector switch to be switched to the SYSTEM position.

To enable a drive to be controlled by the PLC, the following conditions must be met:

Drive must be in SYSTEM on the MCC

Drive must be “ready” at the MCC (all electrical and drive protection in a normal state)

Drive must not be failed by the PLC (start, motion, undercurrent, flow)

Drive must not be inhibited from the SCADA.

When any of the above conditions have not been satisfied the drive will indicate an “Unavailable” status on the SCADA.

2.4.3 SCADA Alarms

The following severities are available within the SCADA system:

Severity Description

None Does not generate any alarm or event when the item enters the relevant state

Event Generates an event when the item enters the relevant state



Alarm Generates an alarm when the item enters the state

The severity selected above for Alarm or Event, is then set to one of the following which are referenced throughout this specification. A description of the typical action for the alarm is provided in the description and is applied unless otherwise stated within this document.

Severity Description

Low Lowest Priority, Local SCADA only, self-resetting if alarm condition is removed (stored as event)

High High Priority, Requires attention, sent via telemetry in addition to local SCADA, requires operator reset

Critical Highest Priority. Inhibits Plant operation. Requires immediate attention, , sent via telemetry in addition to local SCADA, requires operator to reset

2.4.4 Device Digital Status and Alarms to local SCADA

Drive faults caused by any of the following conditions, if applicable to the drive in question, will cause the drive to fail. This will cause the drive to stop and the “Fault” indicator on the MCC to turn on.

Unless the fault condition is self-latched by the field device itself, all faults conditions are latched by the PLC before being alarmed on the SCADA as a minimum.

Signal Delay

Not Ready (MCC) Instantaneous

Fault (PLC) Instantaneous

Failed to Start (PLC) 10 second delay before tripping the drive

Failed to Open (PLC) Travel time plus 30 seconds before tripping the drive

Failed to Close (PLC) Travel time plus 30 seconds before tripping the drive

Torque Instantaneous

Motion Switch (MCC) Input off for 30 second delay before tripping the drive

Flow Switch (MCC) Input off for 40 second delay before tripping the drive

Level Switch (MCC) Instantaneous

Over Current (MCC) Instantaneous

Motor Protection where fitted Instantaneous

Motor Over Temperature Instantaneous

Unless specified in the appropriate process section, the following device status and alarm information will be provided on the SCADA as a minimum.

Tag Name State 0 Description

State 1 Description

State 0 Priority

State 1 Priority

Auto Deselected Selected None Event

Manual Deselected Selected None Event

Off Deselected Selected None Event

State Stopped Running Event Event

Open Limit Transit Opened Event Event

Close Limit Transit Closed Event Event

Health Normal Failed Event Medium



Status Unavailable Available Medium None

Failed to Start Normal Alarm None Medium

Failed to Open Normal Alarm None Medium

Failed to Close Normal Alarm None Medium

Torque Normal Alarm None High

Motion Normal Alarm None High

Motor Protection Normal Tripped None Low

No Flow Normal Alarm None High

High Level Normal Alarm None High

Low Level Normal Alarm None High

Flow Health Normal Failed None Medium

This requires the operator to reset them before the drive can be restarted by the PLC. Once an alarm condition has returned to its normal condition the alarm can be reset by the operator.

PLC latched faults are reset by either of the following methods:

Reset by the operator by changing the local selector switch (MCC) for the drive from SYSTEM to OFF then back to SYSTEM.

Reset by the operator at the SCADA by selecting the drive “reset” button and then selecting the “Auto” button.

Self-latched faults are reset directly at the field device.

2.4.5 Device Analogue Status to Local SCADA

Unless specified in the appropriate process section, the following device status information will be provided on the SCADA.

Parameter Unit Initial Value Range Access

Speed % PLC 0 – 100 Display Only

Position % PLC 0 – 100 Display Only

At plant SCADA historic data logging will be enabled, with compression applied to all data and significant change set at 0.5% of span.

2.4.6 Device Digital Controls from Local SCADA

The operator can control individual drives through SCADA command buttons. Unless specified in the appropriate process section, the following digital controls will be provided on the SCADA.


State 1 Description

State 0 Priority

State 1 Priority

Operate Mode Auto Operator None Low

Remote Start/Stop Stopped Started None Low

Disable Enabled Disabled None Low

Remote Open Deselected Selected None Low

Remote Close Deselected Selected None Low



Drives can be remotely operated from the local SCADA, by operating the “Remote Start” button in Operator Mode. The "Remote Start" and “Remote Stop” is toggled. Once a drive is started by the “Remote Start”, it will continue to operate until the “Remote Stop” button is selected, or the drive is Disabled, or the duty cut out level is reached, or the Opened or Closed limit is reached.

If the Operate mode is selected to Auto, the drive will operate to the PLC sequence commands.

Drives can be Disabled from the local SCADA by the operation of the “Disable” button. This "Disable" is toggled On/Off. While a drive is Disable, it will become unavailable for "Automatic" operation. The Disable will also remove the remote start command if selected.

2.4.7 Drive Hours Run

As a minimum every item of mechanical equipment should have the following hours run information displayed on the SCADA screen with history enabled.

Hours run today since midnight

Hours run yesterday (previous 24 hours – Midnight to Midnight)

Hours run since last reset

Time and date of last reset

Default values are presented in the table below.

Tag Name Description No. Of Decimal Places

HrsTod Hours Run Today (since midnight) 1

HrsYes Hours Run Yesterday (value of above stored at midnight) 1

HrsRun Hours Run (since last reset) 0

Time and Date of last reset -

Hours run today and yesterday are stored as an integer value ≤ 1440 over 24 hours giving discrimination of one minute.

Hours run since last reset, are stored as an integer value ≤ 65535 giving a discrimination of one hour.

2.4.8 Drive Starts

For each drive, the SCADA must also display the number of drive starts in a rolling 60-minute period. The calculation will therefore display the number of drive starts from the current clock time minus 60 minutes to the current clock time. The number of starts per hour will be used for alarming and monitoring purposes.

2.4.9 Analogue Loop Failures

Analogue input loops are checked for open circuit by checking the status register of each physical analogue input card. Analogue output loops are checked for open circuit by checking the status register of each physical analogue output card.

Certain variable speed drives will report loop failure if the drive is NOT selected in SYSTEM at the MCC. To prevent false alarms on the SCADA the analogue output card status register is combined with the SYSTEM input from the MCC.

If an analogue loop is found to be open circuit, the following loop fail alarm information will be provided on the SCADA.




State 1 Description

State 0 Priority

State 1 Priority

LoopFail Normal Alarm None Medium

2.4.10 Flow Totalisation

As a minimum every flow meter should have the following totalisation information displayed on the SCADA screen with history enabled.

Flow today since midnight

Flow yesterday (previous 24 hours - midnight to midnight)

Flow Total

Default values are presented in the table below:

Parameter Unit Initial Value Range Access

Flow Today kL ** PLC 0 – 65535 Display Only

Flow Yesterday kL ** PLC 0 – 65535 Display Only

Flow Total ML *** PLC 0 – 65535 Display Only

** Units for totalised values (L, kL, ML) should be selected based on the scale of the instrument providing the primary source of the signal to be totalised, such that the maximum count for the given period (day / yesterday) does not exceed 65535 counts.

*** Range and Units for Flow Total: Choose Unsigned UINT (65565) or Unsigned Double UDINT (4294967295) based on maximum expected total over at least 7 years.

A flow totalisation summary page will be provided on the plant SCADA. Where Flow totals are displayed on SCADA, the totals will update hourly and on request.

2.4.11 Instrument Calibration Mode

Analytical instruments with analogue inputs to the PLC that may require cleaning or calibration shall have a hold value selection on the SCADA that will capture the current value and hold this value until it is deselected.

This is to allow calibration/cleaning online that would otherwise interrupt the control of the plant or cause unnecessary alarms. Each hold function will initiate a warning alarm immediately.

There will also be a background timer that will trigger an alarm if the hold function has not been deselected after a pre-set time (e.g. 60min). Alarms associated with sample pumps, sample flow switches etc., will be disabled for the duration of the hold function or until the hold function is removed by the operator.

2.4.12 PID Controllers

The PID controllers can be viewed on the SCADA.

Where PID controllers are used, the control system shall monitor each controller performance and will raise a setpoint deviation alarm whenever PV is more than +/- 20% away from SP for greater than (3) minutes.

Members of the Team Leader system group shall have access to change the P, I and D control constants where PID control loops have been used. The “commissioned” P, I, and D values for each PID controller shall be recorded in the “Operations Manual”.



2.4.13 Duty / Standby Pump Queue

When drive status is “Available” the drive shall be placed in a queue or a duty selector. The drive in position number one shall start when a drive is called to run by the control sequence.

When the drive stops the drive shall be rotated to the last position in the queue. If a drive is selected in automatic, is in a queue, and the status alters to unavailable the drive shall be removed from the queue.

2.4.14 Duty Arbiter

Where there is duty/standby equipment, assignment of the duty equipment is implemented via control logic in the PLC. The method of duty assignment as implemented by control logic is termed “duty arbiter”.

For equipment controlled by plant PLC/SCADA the types of duty arbitration are:

Type 1 Intermittent operation plant equipment. When the duty time expires and all of the devices have stopped, the duty order rotates.

Type 2 Continuously running plant (Duty rotation by Operator). When the elapsed duty time of the Duty “1” device reaches 110% of the set duty time, an alarm is raised on SCADA. The alarm notifies the Operator that duty rotation is required. The Operator rotates the duty function by selecting “Rotate Duty Now” on the SCADA. The equipment automatically stops, rotates duty and restarts.

Type 3 Continuously running plant (Automatic duty rotation). When the elapsed duty time of the Duty 1 device expires or when the Operator selects “Rotate Duty Now” on the SCADA, the equipment automatically stops, rotates duty and restarts.

For each type of duty arbiter, the operator can change the priority of all drives in the duty arbiter. The operator must also be able to stop automatic duty rotation.

To account for situations where other plant systems rely on the duty item, the duty/standby item shall not fault immediately when the duty item fails. The system shall only fault immediately if there is no standby system available.

2.5 Plant Power Supply, Switchboard and Auxiliaries

2.5.1 Plant Power Supply Description

If possible the following equipment associated with the MCC is monitored by the PLC system via digital inputs:

Main circuit breaker

UPS unit

Surge protection equipment

Power healthy relay (Incoming Supply)

Power healthy relay (24VDC Supplies)

Phase Failure relay (Line side)

ERGON Supply detected (CO Switch)

Generator Supply Selected (CO Switch)



2.5.2 SCADA Display Screen

The plant power supply and auxiliaries may be provided with a dedicated SCADA page which will display the information detailed below.

Item Device Status

MCC Main C/B Status Relay Circuit Breaker fault/status

MCC ERGON Supply detected OK/Fault

MCC Generator Supply Selected OK/Fault

MCC UPS Unit Healthy/Fault

MCC Phase Failure Relay (line side) OK/Fault

MCC Phase Failure Relay (load side) OK/Fault

MCC Anti-Condensation Heater Control Mode Summer/Winter

Security Security System (Future) Healthy/Fault

2.5.3 Critical Alarms

PLC/HMI generated critical alarms are listed below.:

Signal State 0 Description

State 1 Description

State 0 Priority

State 1 Priority

MCC Main Circuit Breaker Tripped Normal Alarm None High

MCC Phase Failure (Line side) Normal Alarm None High

MCC Phase Failure (Load side) Normal Alarm None High

2.5.4 Warning Alarms

PLC/HMI generated warning alarms are listed below:


State 1 Description

State 0 Priority

State 1 Priority

Surge Protection Fault Normal Alarm None Medium

RTU Communications Fault Normal Alarm None Medium

2.6 PLC and Telemetry Systems

2.6.1 PLC and Telemetry Systems

The PLC equipment and associated communication networks will be displayed on the HMI screens. The screen layouts shall be similar to that on the PLC network electrical drawing.

The screens will show the status of:

All PLC racks

All HMIs

Ethernet / fibre optic communication network.

RTU equipment



2.6.2 Critical Alarms

PLC/HMI generated critical alarms are listed below.:


State 1 Description

State 0 Priority

State 1 Priority

PLC Rack Fault Normal Alarm None High

PLC Communications Fault Normal Alarm None High

Ethernet Device Communications Fault Normal Alarm None High

Telemetry RTU Communication Fault Normal Alarm None High

2.6.3 Warning Alarms

PLC generated warning alarms are listed below:


State 1 Description

State 0 Priority

State 1 Priority

PLC CPU Battery Low Normal Alarm None Medium

Telemetry RTU Battery Low Normal Alarm None Medium

2.6.4 Site Ethernet Communication Network Monitoring

If the hardware is capable, the SCADA shall provide a diagnostics screen for the network, indicating the status of all network connected equipment. Any faults or problems on the network shall initiate appropriate SCADA alarms.



3 Process Control Philosophy

3.1 WTP Control

Reference Drawing Number: To be advised by BSC

3.1.1 Process Overview

Raw water is drawn from the Bogan River by a set of duty/standby raw water pumps and transferred to the WTP for treatment. The interface between the WTP and remote raw water pumps is controlled via the existing Elpro telemetry network RTU.

One of the raw water pumps is variable speed allowing the flow to the WTP to be controlled (speed control of the raw water pump is conducted at the raw water pump station). The other pump is fixed speed and as such operates at a constant flow rate.

After receiving clarification and filtration at the WTP, the water then enters the clear water storage (CWS) tank. From the CWS, the treated water is transferred to two elevated storages. The elevated storage reservoir is monitored via the existing Elpro RTU network back to the WTP. Each elevated storage has a level switch and a level element.

The following automatic control modes can be selected for operation of Nyngan WTP:

Timer Mode - Start the WTP when a specific time of the day is reached and run for an operator adjustable run time, or

Level Mode - Start the WTP when the plant start level set point is reached in the town elevated storage and run the WTP until a high level is reached in the town elevated storage, or

Manual Mode - Start the WTP via a start push button on the SCADA and stop the WTP using a push button on the SCADA.

The operator can select for each control mode whether a high level in the town elevated storage will cause the WTP to cease operation.

Under all automatic control modes, a WTP start will cause plant systems to commence operation as per the sequence detailed below. When a plant stop is required, plant systems will stop operation as per the sequence detailed below.

A raw water turbidimeter is used to continuously monitor the raw water turbidity when the WTP is in operation. The turbidimeter is used for alarming purposes and will shut down the WTP if a high high turbidity condition occurs.

3.1.2 Equipment & Instrument List

The unit process operation involves the following equipment and instruments:

Equipment List

Tag Number Description Equipment Description

MX001 Flash Mixer Fixed Speed Drive

MX008 Flocculator 1 Fixed Speed Drive

MX009 Flocculator 2 Fixed Speed Drive

P561 Liquid Coagulant Dosing Pump Solenoid Pump

P003 Polymer Solution Dosing Pump 1 Fixed Speed Drive

P004 Polymer Solution Dosing Pump 2 Fixed Speed Drive

P011 Sodium Hypochlorite Dosing Pump Fixed Speed Drive



Analogue Instrument List

Tag Number Description Unit Min Max

FM001 Raw Water Flowmeter L/s TBA TBA

AIT131 Raw Water Turbidimeter NTU TBA TBA

LIT912 Town Elevated Storage 1 Level mm TBA TBA

LIT915 Town Elevated Storage 2 Level mm TBA TBA

Digital Instrument List

Tag Number Description

LSL911 Town Elevated Storage 1 Low Level Switch

LSL914 Town Elevated Storage 2 Low Level Switch

FS397 Filtered Water Flow Switch 1

FS398 Filtered Water Flow Switch 2

3.1.3 Control Philosophy

The following section details the automatic control sequence for the WTP start and stop operation.

3.1.3.1 Process Availability

For Nyngan WTP to be available for automatic operation, the following conditions must be met:

The service water system must be available (PSL902)

The compressed air system must be available (PSL901)

Alum dosing must be available though: a One of the dry powder feed systems must be selected for use with alum and be available,

or b The liquid coagulant dosing system must be enabled for use through the SCADA

If pre-soda ash dosing is selected for operation, the respective system must be available

If the sedimentation tank is selected as online, then: a The sedimentation tank flocculators must be available and b The sedimentation tank scraper must be available

If post-soda ash dosing is selected for operation, the respective system must be available

One clear water pump must be available (P009 or P010)

The town elevated storages must not be at high high level (LE912 and LE915)

If any of the above conditions are not met, the WTP will be inhibited from operation or will shut-down if already operating.

3.1.3.2 Process Modes and Operational Sequence

The operator must be able to select the following control modes for automatic operation of Nyngan WTP through the SCADA system:

WTP Level Control Mode – Where the WTP starts at a low level in the town elevated storage and stops when a high level is reached in the town elevated storage.

WTP Time Control Mode – Where the WTP starts at an operator adjustable time of day and runs for an operator adjustable time.

WTP Manual Control Mode – Where the WTP is started by selecting a start push button on the SCADA and is stopped by selecting a stop push button on the SCADA.



Additional details of the automatic control modes are provided below.

Note: In both timer and level control mode, a WTP start can be initiated by a low level being reached in either of the town storages. This low level is as measured by the low level switch in each town storage (LSL911 or LSL914).

3.1.3.2.1 WTP Level Control Mode

The operator can select through the SCADA if either or both town water storage reservoirs are used for control.

When WTP level control mode is selected through the SCADA, if the level in the control town elevated storage is less than the WTP start level (LW1 for reservoir 1 and LW2 for reservoir 2) then a WTP start sequence will be initiated. Where both reservoirs are selected for control, the low level set point which is reached first will be used to initiate a WTP start sequence.

The WTP will then continue to operate until a high level (LW3 for reservoir 1 and LW4 for reservoir 2) is reached in the control town elevated storage. The WTP will then commence a shut-down sequence as described below. Where both reservoirs are selected for control, the high level set point which is reached first will be used to initiate a WTP shut-down sequence.

If the level element for the town elevated storage is not available, WTP level control mode must not be selectable through the SCADA and will be de-selected if already selected requiring another available mode to be selected.

3.1.3.2.2 WTP Timer Control Mode

When WTP timer control mode is selected through the SCADA and the current time of day is equal to the WTP start time of day (TW1) then a WTP start sequence will be initiated.

The WTP will then run for the minimum of the WTP run time set point TW2 or until the level in the control town elevated storage is high (LW3 for reservoir 1 and LW4 for reservoir 2). The WTP will then commence a shut-down sequence as described below. Where both reservoirs are selected for control, the high level set point which is reached first will be used to initiate a WTP shut-down sequence.

3.1.3.2.3 WTP Manual Control Mode

The operator must be able to initiate a WTP start sequence to occur by selecting a WTP start button on the SCADA. When the WTP start is initiated manually, a WTP excessive run timer (TW3) starts. If the WTP runs for greater than time TW3 a WTP excessive run time alarm will be raised.

In WTP manual control mode, the operator can select for the WTP to operate until the level in the town elevated storage is at high level (LW3 for reservoir 1 and LW4 for reservoir 2) or the operator can select a WTP stop button on the SCADA. The WTP will then commence a shut-down sequence as described below. Where both reservoirs are selected for control, the high level set point which is reached first will be used to initiate a WTP shut-down sequence.

3.1.3.2.4 WTP Start and Stop Sequences

When a WTP start is initiated for any of the reasons described above (i.e. level control, timer control or manual start) the following sequence is to be used to bring individual processes online:

A raw water transfer start signal shall be sent to the raw water pump station, Then,

Start the selected duty raw water pump (P101 or P121) . Then, when the raw water flow is greater than FRW1. Then, a Start the flash mixer (MX001). Then, b If the sedimentation tank is selected as online through the SCADA, start both flocculator

drives (MX008 and MX009). Then, c Commence clarifier and sedimentation tank de-sludge automatic control as described in

Section 3.2. Then,



d Commence filter automatic control as described in Section 3.3. Then, e If liquid coagulant dosing is selected for operation, start the liquid coagulant dosing pump

(P561). Then, f If powdered alum dosing is selected for operation the commence automatic control of the

alum dosing system as described in Section 3.5. Then, g If soda ash pre-dosing is selected for operation, commence automatic control of the ash

pre-dosing system as described in Section 3.5. Then, h Start the duty polymer dosing pump (P003 or P004). Then,

When a filtered water flow switch (FS397 or FS398) indicates the presence of filtered water flow. Then, a Start the sodium hypochlorite dosing pump (P011). Then, b If soda ash post-dosing is selected for operation, commence automatic control of soda ash

post -dosing system as described in Section 3.5.

When a WTP stop is initiated for any of the reasons described above (i.e. level control, timer control or manual start) the following sequence is to be used to bring individual processes online:

If clarifier and sedimentation tank de-sludge on plant shut-down is selected, then initiate a clarifier and sedimentation tank de-sludge as described in Section 0. Then wait until the clarifier de-sludge has completed to proceed to the next step.

Stop raw water transfer, then

When the raw water flow is less than FRW1, a Stop liquid alum dosing if selected for operation b Stop the duty polymer dosing pump c Stop powdered alum dosing, as described in Section 3.5 if selected for operation d Stop the soda ash pre dosing, as described in Section 3.5 if selected for operation, Then e Stop the flash mixer (MX001) and flocculators (MX008 and MX009). Then,

Cease automatic operation of the filter as described in Section 3.3. Then,

When a filtered water flow switch (FS397 or FS398) indicates no filtered water flow is present a Stop the soda ash pre dosing, as described in Section 3.5 if selected for operation b Stop the sodium hypochlorite dosing pump (P011), Then

The type of duty arbitration used for the polymer dosing pumps is shown in the table below.

System No. of Devices

Duty (D) / Standby (S) Type of Arbiter

Polymer Dosing Pumps 2 D/S Type 1

When raw water transfer is initiated a no flow timer (TRW1) will also start. If by the time TRW1 expires the raw water flow is less than FRW1, start-up of the WTP will cease and a WTP raw water no flow alarm will be generated.

3.1.4 Adjustable Parameters

The table below lists adjustable parameters relevant to the unit process.

Tag Description Access Unit Format Min Max Initial

WTP Time Control Mode Level 2 On Off Off

WTP Level Control Mode Level 2 On Off On

Elevated Storage Level Inhibit in Manual Mode

Level 2 On Off Off

Elevated Storage 1 Used for Control Level 2 Yes/No

Elevated Storage 2 Used for Control Level 2 Yes/No



TW1 WTP Start Time Level 2 24 Hour 00:00 00:00 23:59 TBA

TW2 WTP Run Time Level 2 Minutes 0DP 15 1440 TBA

TW3 WTP Manual Excessive Run Time Level 2 Minutes 0DP 15 1440 TBA

LW1 WTP Elevated Storage 1 Start Level Level 2 m 2DP 0.00 TBA TBA

LW2 WTP Elevated Storage 2 Start Level Level 2 m 2DP 0.00 TBA TBA

LW3 WTP Elevated Storage 1 Stop Level Level 2 m 2DP 0.00 TBA TBA

LW4 WTP Elevated Storage 2 Stop Level Level 2 m 2DP 0.00 TBA TBA

WTP Elevated Storage 1 Low Low Level

Level 2 m 2DP 0.00 TBA TBA

WTP Elevated Storage 2 Low Low Level


WTP Elevated Storage 1 High High Level


WTP Elevated Storage 2 High High Level


TRW1 Plant No-Flow Delay Timer Level 1 Seconds 0DP 0 TBD TBD

FRW1 Raw Water Flow Set Point Level 1 L/s 1DP 0 TBD TBD

AIT131 Raw Water Turbidity High Set Point Level 1 NTU 1DP 0 TBD TBD

AIT131 Raw Water Turbidity High High Set Point

Level 1 NTU 1DP 0 TBD TBD

Other parameters as required for equipment offered.

TBD TBD TBD TBD

*DP refers to the number of decimal places required for the SCADA entered value.

3.1.5 Alarms

The table below lists SCADA/PLC generated alarms relevant to the system operation. All alarms listed below require SCADA indication when activated.

No. Tag Number Description SCADA Priority

1 WTP Unavailable Critical

2 WTP Excessive Run Time in Manual Mode Low

3 FM001 Raw Water No Flow Alarm Critical

4 FM001 Raw Water Flowmeter Failed Low

5 AIT131 Raw Water Turbidimeter Failed Low

6 AIT131 Raw Water Turbidity High Low

7 AIT131 Raw Water Turbidity High High Critical

8 FM001 Raw Water Flowmeter Failed Low

9 MX001 Flash Mixer Failed Critical

10 MX008 Flocculator 1 Failed Medium

11 MX009 Flocculator 2 Failed Medium

12 LE912 WTP Elevated Storage 1 Low Low Level Critical

13 LE915 WTP Elevated Storage 2 Low Low Level Critical

14 LE912 WTP Elevated Storage 1 High High Level Critical

15 LE915 WTP Elevated Storage 2 High High Level Critical

16 P561 Liquid Coagulant Dosing Pump Failed Critical



17 P003 Polymer Solution Dosing Pump 1 Failed Low

18 P004 Polymer Solution Dosing Pump 2 Failed Low

19 P011 Sodium Hypochlorite Dosing Pump Failed Critical

16 Other parameters as required for equipment offered.

3.2 Clarification and Sedimentation



Coagulated water flows to the newer sedimentation tank and/or the older clarifier. Control of the flow split between the sedimentation tank and the clarifier is through operation of manual valves of the inlet to each process. The operator can select to take either the clarifier or the sedimentation tank offline through the SCADA. The SCADA must then prompt the operator through a pop-up screen to ensure the clarifier and sedimentation tank inlet valves are in the correct position.

A flowmeter is provided for the raw water and for the clarifier inlet. The flow to the sedimentation tank shall be calculated by subtracting the clarifier inlet flow from the raw water flow. The calculated sedimentation tank inlet flow shall be provided as an instantaneous flow signal as well as a volume total as per Section 2.4.10.

For the clarifier, water enters a central flocculation well, where contacting of the coagulated water with flocculated solids helps to promote settlement. Water within the flocculation water then flows towards the base of the clarifier, allowing solids to settle. The clarified water then overflows the peripheral weir of the clarifier before flowing to the filters.

Settled solids accumulate in the bottom of the clarifier and are periodically removed by opening a de-sludge valve connected to a pipe in the base of the clarifier.

For the sedimentation tank, flocculated water flows through the tank with the residence time provided allowing solids to settle. A rake drive operates continuously when the sedimentation tank is in operation to scrape settled solids to a hopper at the inlet of the sedimentation tank.

Settled solids accumulate in the bottom of the sedimentation tank and are periodically removed by opening a de-sludge valve connected to a pipe in the base of the sedimentation tank sludge hopper.

The operator can select three different modes of operation for sludge removal from the clarifier and sedimentation tank:

Timer based – where the clarifier and sedimentation tank de-sludge valves open after an operator adjustable plant run time

Inflow Volume – where the clarifier and sedimentation de-sludge valves open once every time an operator adjustable volume of raw water enters the WTP.

Inflow Solids Mass where the clarifier and sedimentation de-sludge valves open once every time an operator adjustable mass of solids enters the WTP. The mass of solids being calculated based on the inlet turbidity and flow.





Equipment List


EV001 Clarifier De-sludge Valve Electrically Operated Valve

EV002 Sedimentation Tank De-sludge Valve Electrically Operated Valve



FM004 Clarifier Inlet Flowmeter L/s TBA TBA



ZS222 Sedimentation Tank Scraper Plough Switch Leading Edge

ZS223 Sedimentation Tank Scraper Plough Switch Trailing Edge


The following section details the automatic control sequence for the clarifier and sedimentation tank (sed. tank).


The operator can select any of the following three modes of operation for control of the clarifier and the sedimentation tank de-sludge:

Time based clarifier de-sludge

Volume based clarifier de-sludge

Mass based clarifier de-sludge

The operator must also be able to inhibit de-sludge operation from occurring or manually initiate a clarifier (or sed. tank) de-sludge through the SCADA system.

The selected mode of de-sludge will be displayed on the SCADA screen.

To prevent excessive volume loss when in mass or volume based de-sludge modes, the operator can limit the frequency of clarifier de-sludge operation.

A delay timer TC1 will start after each de-sludge operation. If the control mode calls for a de-sludge before TC1 expires then the de-sludge will be delayed until TC1 expires. If, however a de-sludge is manually initiated, the manual de-sludge will be allowed to occur and TC1 will be reset.

Note, the suffix “A” is used for set points relating to the clarifier and the suffix “B” for set points relating to the sedimentation tank throughout Section 0.

The sedimentation tank scraper is fitted with leading and trailing plough switches (ZS222 and ZS223) which are used to automatically stop the scraper assembly when there is an obstruction on the track.

3.2.3.1.1 Time Based Clarifier and Sed. Tank De-Sludge

If time based de-sludge is selected then the de-sludge delay timer TC2 starts as part of the plant start sequence or when this mode of operation is selected through the SCADA.

Once the de-sludge delay timer (TC2A for the clarifier and TC2B for the sedimentation tank) expires, the following occurs:



The de-sludge valve opens (EV001 opens for the clarifier and EV002 opens for the sedimentation tank).

an operator adjustable de-sludge timer TC3 starts

When TC3 expires the de-sludge valve closes (EV001 closes for the clarifier and EV002 closes for the sedimentation tank) and the clarifier de-sludge timers (TC2 and TC3) reset.

The operator can also select through the SCADA for a de-sludge to occur on plant shutdown. If a de-sludge before plant shut-down is selected to occur, the de-sludge valves (EV001 for the clarifier and EV002 for the sedimentation tank) will open for time TC3(A or B) prior to shutting down the raw water pumps as described in Section 3.1. The de-sludge before plant shutdown is available in all de-sludge control modes.

3.2.3.1.2 Volume Based Clarifier and Sed. Tank De-Sludge

The PLC continually records the raw water flow (FM001) integrated volume. If volume based de-sludge is selected, then the de-sludge volume counter (VSR1A for the clarifier and VSR1B for the sedimentation tank) starts as part of the plant start sequence or when this mode of operation is selected through the SCADA.

Once the inlet flow volume counter (VSR1A for the clarifier and VSR1B for the sedimentation tank) reaches the de-sludge volume set point VC1A (or VC1B for the sedimentation tank), the following occurs:

The de-sludge valve opens (EV001 opens for the clarifier and EV002 opens for the sedimentation tank).

an operator adjustable de-sludge timer TC3A for the clarifier and TC3B for the sedimentation tank starts

When TC3(A or B) expires the de-sludge valves close (EV001 closes for the clarifier and EV002 for the sedimentation tank) and the de-sludge volume counter (VSR1A or B) resets.

3.2.3.1.3 Mass Based Clarifier and Sed. Tank De-Sludge

The PLC continually records the theoretical raw water solids content based on the raw water flow (FM001) and the raw water turbidity (AIT131).

The clarifier inflow solids mass (MSR1A) in kg/minute is determined based on the following equation:

Where:

QA is the instantaneous clarifier inflow in L/s as recorded by FM004

C is the instantaneous raw water turbidity in NTU as recorded by AIT131

The sedimentation tank inflow solids mass (MSR1B) in kg/minute is determined based on the following equation:

Where:

QB is the instantaneous sedimentation tank inflow in L/s, calculated by subtracting the clarifier inflow as recorded buy FM004 from the sedimentation tank inflow as calculated by FM001.



C is the instantaneous raw water turbidity in NTU as recorded by AIT131

If mass based clarifier de-sludge is selected, then the de-sludge mass counter (MSR1A or B) starts as part of the plant start sequence or when this mode of operation is selected through the SCADA.

Once the inlet solids mass (MSR1A or B) reaches the de-sludge mass set point MC1, the following occurs:

The de-sludge valve opens EV001 opens for the clarifier and EV002 opens for the sedimentation tank).

an operator adjustable de-sludge timer TC3A for the clarifier and TC3B for the sedimentation tank starts

When TC3(A or B) expires the de-sludge valves close (EV001 closes for the clarifier and EV002 for the sedimentation tank) and the de-sludge mass counter (MSR1A or B) resets and the de-sludge timer TC3A or B resets.

If the raw water turbidimeter (AIT131) is unavailable the operator must not be able to select mass based clarifier de-sludge. If mass based clarifier de-sludge is already selected for operation then volume based clarifier de-sludge must be automatically selected for use.

If either raw water flowmeter (FM001 or FM004) is unavailable the operator must not be able to select mass or volume based clarifier de-sludge. If mass or volume based clarifier de-sludge is already selected for operation then timer based clarifier de-sludge must be automatically selected for use.

3.2.3.1.4 Clarifier and Sed. Tank Operation after Power Failure

The operator can select through the SCADA whether a clarifier or sedimentation tank de-sludge occurs automatically after a power failure. If clarifier de-sludge after power failure is selected, then a clarifier de-sludge will occur when clarifier de-sludge is enabled as part of the WTP start sequence.






Clarifier Online Level 2 On/Off

Sed. Tank Online Level 2 On/Off

Time Based Clarifier De-sludge Level 2 0n Off On

Volume Based Clarifier De-sludge Level 2 0n Off Off

Mass Based Clarifier De-sludge Level 2 0n Off Off

Clarifier De-sludge on Plant Shut-down

Level 2 0n Off Off

Clarifier De-sludge Inhibited Level 2 0n Off Off

Clarifier De-sludge After Power Fail Level 2 0n Off Off

TC1A Clarifier De-Sludge Frequency Level 2 Minutes 1DP 0 1440 10

TC2A Clarifier De-Sludge Delay Time Level 2 Minutes 1DP 0 1440 10

TC3A Clarifier De-Sludge Run Time Level 2 Seconds 0DP 0 600 25

VC1A Clarifier De-Sludge Volume Set Point Level 1 m3 1DP 0.0 999 9.0

MC1A Clarifier De-Sludge Mass Set Point Level 1 kg 2DP 0.00 5.00 0.25

Time Based Sed. Tank De-sludge Level 2 0n Off On

Volume Based Sed. Tank De-sludge Level 2 0n Off Off

Mass Based Sed. Tank De-sludge Level 2 0n Off Off

Sed. Tank De-sludge on Plant Shut-down

Level 2 0n Off Off

Sed. Tank De-sludge Inhibited Level 2 0n Off Off

Sed. Tank De-sludge After Power Fail Level 2 0n Off Off

TC1B Sed. Tank De-Sludge Frequency Level 2 Minutes 1DP 0 1440 10

TC2B Sed. Tank De-Sludge Delay Time Level 2 Minutes 1DP 0 1440 10

TC3B Sed. Tank De-Sludge Run Time Level 2 Seconds 0DP 0 600 25

VC1B Sed. Tank De-Sludge Volume Set Point Level 1 m3 1DP 0.0 999 9.0

MC1B Sed. Tank De-Sludge Mass Set Point Level 1 kg 2DP 0.00 5.00 0.25


TBD TBD TBD TBD


3.2.5 Alarms


No. Tag Number Description SCADA Priority

1 EV001 Clarifier De-sludge Valve Fault Medium

2 EV002 Sedimentation Tank De-sludge Valve Fault Medium

3 FM004 Clarifier Inlet Flowmeter Failed Medium

4 Other parameters as required for equipment offered.

3.3 Filtration





Clarified water from the clarifier and sedimentation tank flows via gravity into five open dual media filters. Each filter is fitted with an inlet overflow weir which assists in the even distribution of the clarified water between the filters.

The water level above the filter is used as the driving head for flow through the filter media. The flocculated material collects within the void space between the filter media and the filtered water passes through the media and into the plenum space under each filter.

As flocculated solids accumulate within each filter the headloss through the filter media increases. To maintain a set level a control valve on the filter outlet slowly opens to compensate for in the increase in headloss to maintain a set level in the filter.

To remove the solids build-up within the filter media, the filters must be air scoured and then backwashed.

The air scouring and backwashing process is manual and requires the filter inlet to be manually isolated prior to selecting the filter as offline through the SCADA. During the manual filter backwash, a local selector switch is used to open the filter outlet valve to drain down the filter for backwashing. When the selector switch is toggled, the filter outlet valve will automatically move to the drain down position set point.

Following completion of the manual air scour and backwash process, the filter inlet valves are opened manually prior to selecting the filters as online through the SCADA system. Once a filter is selected as online, normal filter level control can resume.



Equipment List


PCV003 Filter 1 Filtered Water Outlet Valve Pneumatic Control Valve







LIT301 Filter 1 Level Sensor mm 0 10,000

AIT308 Filter 1 Outlet Turbidity NTU 0 5












The following section details the automatic control sequence for the filtration process.


The operator must be able to select a filter as on or offline through the SCADA system. When a filter is selected as offline, the following valves will close if not already closed:

The filtered water outlet valve

If a filter is selected as online through the SCADA, the filter will be called to start as part of the WTP start-up sequence described in Section 3.1. When a filter is called to start, the following will occur:

The filter outlet valve will move to the SCADA adjustable filter start position set point (PF1).

The difference between the filter level set point (LF1A for Filter 1, LF1B for Filter 2, LF1C for Filter 3, LF1D for Filter 4 and LF1E for Filter 5) and the actual filter level (LE301 for Filter 1, LE321 for Filter 2, LE341 for Filter 3, LE361 for Filter 4 and LE381 for Filter 5) will be used as the input to a PID controller, the output of which will be used to:

Close the filter outlet valve if the level in the filter is lower than the set point and

Open the filter outlet valve if the level in the filter is higher than the set point.

If during normal filter operation, the filter level varies from the set point by greater than deadband FDB1 for more than TF1, then raise a filter level control fail alarm.

When a filer is called to shut down, the following will occur:

The filter outlet valve will close, then

The filter run timer will stop.

3.3.3.1.1 Filtration System Fault Modes

If the filtered water turbidity is greater than an operator adjustable high set point (TUF1), for operator adjustable time, TF2, then raise a high filtered water turbidity alarm. If the filtered water turbidity is greater than an operator adjustable high high set point (TUF2) at any time whilst the WTP is operating, then shut down the WTP and raise an alarm.

A high level in a filter will also raise an individual filter high level alarm.




Filter 1 Online/Offline Level 2 On Off Off





PF1A Filter 1 Start-up Valve Position Level 1 % 0DP 0 100 TBD

PF1B Filter 2 Start-up Valve Position Level 1 % 0DP 0 100 TBD

PF1C Filter 3 Start-up Valve Position Level 1 % 0DP 0 100 TBD

PF1D Filter 4 Start-up Valve Position Level 1 % 0DP 0 100 TBD



PF1E Filter 5 Start-up Valve Position Level 1 % 0DP 0 100 TBD

LF1A Filter 1 Level Set Point Level 2 mm 0DP 0 10,000 TBD

LF1B Filter 2 Level Set Point Level 2 mm 0DP 0 10,000 TBD

LF1C Filter 3 Level Set Point Level 2 mm 0DP 0 10,000 TBD

LF1D Filter 4 Level Set Point Level 2 mm 0DP 0 10,000 TBD

LF1E Filter 5 Level Set Point Level 2 mm 0DP 0 10,000 TBD

TUF1 Filter High Turbidity Limit Level 1 NTU 1DP 0.0 5.00 TBD

TUF2 Filter High High Turbidity Limit Level 1 NTU 1DP 0.0 5.00 TBD

TF2 Filter High Turbidity Delay Time Level 1 Seconds 0DP 0 999 TBD

FDB1 Filter Control Deadband Level 2 mm 0DP 0 10,000 TBD

TF1 Filter Deadband Control Timer Level 1 Seconds 0DP 0 9999 TBD

LF2A Filter 1 High Level Level 2 mm 0DP 0 10,000 TBD

LF2B Filter 2 High Level Level 2 mm 0DP 0 10,000 TBD

LF2C Filter 3 High Level Level 2 mm 0DP 0 10,000 TBD

LF2D Filter 4 High Level Level 2 mm 0DP 0 10,000 TBD

LF2E Filter 5 High Level Level 2 mm 0DP 0 10,000 TBD

PF1A Filter 1 Drain Down Valve Position Level 1 % 0DP 0 100 TBD

PF1B Filter 2 Drain Down Valve Position Level 1 % 0DP 0 100 TBD

PF1C Filter 3 Drain Down Valve Position Level 1 % 0DP 0 100 TBD

PF1D Filter 4 Drain Down Valve Position Level 1 % 0DP 0 100 TBD

PF1E Filter 5 Drain Down Valve Position Level 1 % 0DP 0 100 TBD


TBD TBD TBD TBD

DP refers to the number of decimal places required for the SCADA entered value.

3.3.5 Alarms


Tag Number Description SCADA Priority

LIT301 Filter 1 Level Sensor Failed Medium

LIT301 Filter 1 High Level Medium

LIT301 Filter 1 Level Outside of Deadband Medium

AIT308 Filter 1 Outlet Turbidity Failed Medium




















3.4 Clear Water Storage & Transfer



Filtered water flows via gravity directly to the CWS tanks at Nyngan WTP. A pair of duty/standby fixed speed centrifugal pumps transfer treated water from the CWS tank at Nyngan WTP to the elevated storage reservoirs in the Nyngan Township. The control of the elevated reservoirs is monitored via the existing Elpro telemetry network back to the WTP.

The two treated water pumps operate in duty/standby configuration with the duty treated water pump being enabled as part of the WTP start-up sequence.

The duty treated water pump once enabled will start on a high level in the CWS and stop on a low level being reached in the CWS.

A flowmeter in the discharge line from the treated water pumps is used for monitoring and low flow protection for the transfer pumps.



Equipment List


P009 Clear Water Pump 1 Fixed Speed

P010 Clear Water Pump 2 Fixed Speed



FM003 Clear Water Flowmeter L/s 0.0 TBD

AIT001 Clear Water Turbidity mg/L 0.00 2.00

AIT431 Clear Water pH 0.00 14.00

AIT432 Clear Water Free Chlorine mg/L 0.00 5.00

AIT433 Clear Water Fluoride mg/L 0.00 2.00

LIT436 Clear Water Storage Level m 0.00 TBD





FS401 Clear Water Pump 1 Flow Switch

FS411 Clear Water Pump 2 Flow Switch

LSH070 Clear Water Storage Low Level Switch

LSL071 Clear Water Storage High Level Switch

3.4.3 Duty Arbitration

The type of duty arbitration used in this section of the process is shown in the table below.

System No. of Devices

Duty (D) / Standby (S) Type of Arbiter

Clear Water Pumps 2 D/S Type 1


The following section details the automatic control sequence for the treated water transfer process.


For the high lift pumps to be ready for automatic operation:

At least one treated water transfer pump (P009 or P010) must be available


When a high level (LT1) is reached in the CWS based on LE436, the selected duty treated water pump will start.

When a low level (LT2) is reached in the CWS based on LE436, the selected duty treated water pump will stop and the pump duty automatically rotates.

If a high level is reached in the elevated storage (LE912), then the duty treated water pump will stop.

When the duty treated water pump starts, a no-flow run timer (TT1) also starts. If the treated water flow does not exceed TF1 before timer TT1 exceeds TTV1, then fault the duty treated water pump.

3.4.4.3 Fault Conditions

If LE436 fails, the selected duty treated water pump will start when LSH435 is activated and stop when LSL434 is activated.

The following conditions must cause the WTP to shut down and the duty treated water pump to cease operating after a PLC delay time:

A high high clear water turbidity

A high high clear water chlorine residual

A low low clear water chlorine residual

A high high clear water pH

A low low clear water pH

A high high clear water fluoride






LT1 CWS High Level Level 2 m 2DP 0 TBD TBD

LT2 CWS Low Level Level 2 m 2DP 0 TBD TBD

TF1 Clear Water Minimum Flow Level 1 L/s 0DP 0 TBD TBD

TTV1 Clear Water Pump No-Flow Timer Level 1 Seconds 0DP 0 TBD TBD

AIT001 Clear Water Turbidity High Level 2 NTU 2DP 0 TBD TBD

AIT001 Clear Water Turbidity High High Level 2 NTU 2DP 0 TBD TBD

AIT432 Clear Water Free Chlorine Residual Low Low

Level 2 mg/L 2DP 0 TBD TBD

AIT432 Clear Water Free Chlorine Residual Low


AIT432 Clear Water Free Chlorine Residual High


AIT432 Clear Water Free Chlorine Residual High High


AIT431 Clear Water pH Low Low Level 2 2DP 0 TBD TBD

AIT431 Clear Water pH Low Level 2 2DP 0 TBD TBD

AIT431 Clear Water pH High Level 2 2DP 0 TBD TBD

AIT431 Clear Water pH High High Level 2 2DP 0 TBD TBD

AIT433 Clear Water Fluoride High Level 2 mg/L 2DP 0 TBD TBD

AIT433 Clear Water Fluoride High High Level 2 mg/L 2DP 0 TBD TBD


TBD TBD TBD TBD




3.4.6 Alarms



Clear Water Transfer Unavailable High

P009 Clear Water Pump 1 General Fault Low

P010 Clear Water Pump 2 General Fault Low

LIT436 Clear Water Storage Level Loop Fault Low

FM003 Clear Water Flow Loop Fault High

AIT001 Clear Water Turbidity Loop Fault High

AIT432 Clear Water Free Chlorine Residual Loop Fault High

AIT431 Clear Water pH Loop Fault High

AIT001 Clear Water Turbidity High Medium

AIT001 Clear Water Turbidity High High High

AIT432 Clear Water Free Chlorine Residual Low Low High

AIT432 Clear Water Free Chlorine Residual Low Medium

AIT432 Clear Water Free Chlorine Residual High Medium

AIT432 Clear Water Free Chlorine Residual High High High

AIT433 Clear Water Fluoride Residual High Medium

AIT433 Clear Water Fluoride Residual High High High

AIT431 Clear Water pH Low Low High

AIT431 Clear Water pH Low Medium

AIT431 Clear Water pH High Medium

AIT431 Clear Water pH High High High


3.5 Alum and Soda Ash Dosing Systems



Three dry powder feeders provide alum dosing as well as soda ash pre and post dosing. Each dry powder feeding system consists of:

A variable speed screw feeder which draws powder from the base of the silo and deposits it in the mixing/dosing tank.

A mixer which operates to combine the powder (alum or soda ash) with process water to form a slurry which is then dosed.

A fixed speed dosing pump which transfers the slurry to the dosing point.

A process water connection with a float valve provides a continual supply of water, replacing the liquid removed by the slurry transfer pump.

The operator can select through the SCADA the dose point to be used for each dosing system from the following options:



Alum Dosing

Soda Ash Pre-Dosing

Soda Ash Post-Dosing

If two dosing systems are selected for dosing to the same location, these systems will operate in duty standby with the standby system automatically operating if there is a failure of the duty system.

The selection of the dosing location requires operation of manual valves. If an operator changes the dosing location for a dosing system, a pop-up will be automatically generated to warn the operator that they must also operate these manual valves to change the dose location of the dosing system.

3.5.2 Equipment and Instrument List


Equipment List


MX004 Dry Chemical Dosing System 1 Mixer Fixed Speed Drive

SC002 Dry Chemical Dosing System 1 Screw Feeder Variable Speed Drive

P006 Dry Chemical Dosing System 1 Transfer Pump Fixed Speed Drive








The following section details the automatic control sequence for the powdered chemical dosing systems.


For each dry chemical dosing system to be available, the following conditions must be met:

The screw feeder must be available

The mixing/dosing tank mixer must be available

The solution transfer pump must be available

3.5.3.2 Process Modes and Operational Sequence Alum Dosing

The mixer within each mixing/dosing tank shall run continually when a dosing system is selected for operation (i.e. whether the WTP is operating or not).

When a dosing system is selected for operation and is called to start as part of the WTP start sequence described in Section 3.1, the dosing system transfer pump and screw feeder will be called to start.

When a dosing system is selected for operation and is called to stop as part of the WTP stop sequence described in Section 3.1, the dosing system screw feeder will be called to stop. The transfer pump shall then continue to run for TDC1 following the cessation of WTP operation.






Dosing System 1 Dedicated to Alum/Pre-Soda Ash/Post Soda Ash

Level 2


Level 2


Level 2

TDC1A Dosing System 1 Run-on Time Level 2 Seconds 0DP 0 9999 TBA

TDC1B Dosing System 2 Run-on Time Level 2 Seconds 0DP 0 9999 TBA

TDC1C Dosing System 3 Run-on Time Level 2 Seconds 0DP 0 9999 TBA


TBD TBD TBD TBD


3.5.5 Alarms



Alum Dosing Unavailable High

Pre-Soda Ash Dosing Unavailable Medium

Post Soda Ash Dosing Unavailable High

MX004 Dry Chemical Dosing System 1 Mixer Fault Low

SC002 Dry Chemical Dosing System 1 Screw Feeder Fault Low

P006 Dry Chemical Dosing System 1 Transfer Pump Fault Low








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