SEWAGE PUMP STATION DESIGN STANDARD - · PDF fileSEWAGE PUMP STATION DESIGN STANDARD Supplementary Information to the WSAA Sewage Pumping Station Code of Australia WSA 04-2005-2.1

SEWAGE PUMP STATION DESIGN STANDARD

Supplementary Information to the WSAA Sewage Pumping Station

Code of Australia WSA 04-2005-2.1

Western Water January 2013

CAPITAL DEVELOPMENT | SEWAGE PUMP STATION DESIGN STANDARD

Version: 1.1 Controlled Document Document Owner: STANDARDS TEAM Ref: CAPDEV - STANDARD - SPS DESIGN Page 2 of 43 Uncontrolled when Printed Authorised: GENERAL MANAGER SUSTAINABLE WATER SOLUTIONS Date Authorised: 31 DECEMBER 2012

Executive Summary

This Design Standard has been produced as a guide for use by technical personnel involved with the design and construction of sewage pumping stations within Western Water’s service area. The design and construction of sewage pumping stations and associated pressure mains required for provision of services to subdivisions and other land development works should be carried out in accordance with this Design Standard and the WSAA Sewage Pumping Station Code of Australia WSA 04-2005-2.1 (“the SPS Code”). The requirements set out in this Design Standard take precedence over those in the SPS Code. This document is a guideline only, and not intended to be a detailed specification for the purposes of the design and construction of sewage pumping stations. Designers and constructors are responsible for the respective aspects of the design and construction process and the justification of any variations from the requirements set out in the SPS Code and this Design Standard. Where there are any discrepancies or inconsistencies between the SPS Code, this Design Standard, or any other documents, standards or practices these should be discussed with Western Water prior to proceeding. Enquiries or suggestions relating to the information set out in this Design Guide are welcome and can be directed via email to [email protected] Western Water will update this document as changes become necessary, and the most up to date version will be available on our website. This edition applies to all developments and sewage pumping station design projects issued to commence design on or after the publication date unless otherwise stated by Western Water.

mailto:[email protected]



Part 0 : Glossary of Terms, Abbreviations and References

II Abbreviations Additional items:

EST Emergency Storage Tank FLC Full Load Current HRC High Rupture Capacity L/s Litres per second NC Non conformance PWWF Peak Wet Weather Flow SPEC Specification WW Western Water Additional section:

V Western Water Standards Pumping stations should be designed and constructed in accordance with all relevant Western Water standards, including: • Western Water SCADA Standards; • Western Water Sewerage Design Standard: Supplement to WSA 02-2002-2.3 WSAA Sewerage

Code of Australia Melbourne Retail Agencies Edition; and • Western Water Bushfire Requirements for Asset Protection.



Table of Contents

Part 0 : Glossary of Terms, Abbreviations and References ........................................................... 3

II Abbreviations ............................................................................................................ 3

V Western Water Standards ........................................................................................... 3

Part 1: Planning and Design .................................................................................................... 8

1.0 GENERAL .................................................................................................................. 8

1.1 Scope ....................................................................................................................... 8

1.5 Planning and Design Responsibilities and Interfaces ....................................................... 8

1.5.3 Design responsibilities .......................................................................................... 8

1.6 Sewer System Design Approach .................................................................................. 8

1.6.3 Objectives of design ............................................................................................. 8

2 CONCEPT DESIGN ......................................................................................................... 9

2.1 Life Cycle Considerations ............................................................................................ 9

2.14 Signage ...................................................................................................................... 9

2.17 Commissioning Plan ................................................................................................... 9

2.17.1 General .............................................................................................................. 9

3 GENERAL DESIGN .................................................................................................... 10

3.2 Design Tolerances .................................................................................................... 10

3.7 Easements .............................................................................................................. 10

3.14 Bushfire Requirements ............................................................................................. 10

4 MATERIALS DESIGN ................................................................................................. 10

4.2 Corrosion Protection ................................................................................................. 10

4.2.2 Concrete surfaces .............................................................................................. 10

4.2.3 Metallic materials............................................................................................... 10

5 PUMPING SYSTEM .................................................................................................... 11

5.2 Inlet MH ................................................................................................................. 11

5.2.1 Site selection .................................................................................................... 11

5.2.5 Site layout and access ........................................................................................ 11

5.3 Inlet MH ................................................................................................................. 12

5.3.2 Design ............................................................................................................. 12

5.3.3 Pumping station wet-well isolating valve ............................................................... 12

5.4 Wet-Well Design ...................................................................................................... 13

5.4.1 General ............................................................................................................ 13

5.4.4 Control levels .................................................................................................... 13



5.4.6 Benching .......................................................................................................... 13

5.4.7 Washers ........................................................................................................... 13

5.5 Wet-Well Ventilation................................................................................................. 13

5.6 Overflow Containment .............................................................................................. 14

5.6.2 Emergency Storage............................................................................................ 14

5.6.4 Emergency Relief System ................................................................................... 15

5.7 Ladders and Platforms .............................................................................................. 16

5.8 Wet-Well Access Covers............................................................................................ 16

5.9 Safety Systems ....................................................................................................... 16

6 PUMPING SYSTEM .................................................................................................... 17

6.1 Staging .................................................................................................................. 17

6.2 Hydraulic Design...................................................................................................... 17

6.2.1 Design Flow Estimation ...................................................................................... 17

6.4 Pump Selection........................................................................................................ 18

6.6 Submersible Pumps ................................................................................................. 18

6.8 Pump Starters and Variable Speed Drives ................................................................... 18

7 POWER SYSTEM ...................................................................................................... 19

7.1 General .................................................................................................................. 19

7.2 Power Supplies ........................................................................................................ 19

7.3 Power and Control Cubicle ........................................................................................ 19

8 CONTROL AND TELEMETRY SYSTEM ........................................................................... 20

8.3 Pumping Control ...................................................................................................... 20

8.5 Alarm, Status Monitoring and Control Telemetry .......................................................... 22

8.6 Telemetry Hardware ................................................................................................. 23

8.7 Operating Levels and Default Settings ........................................................................ 23

8.8 Equipment and Devices ............................................................................................ 24

9 WET-WELL PIPEWORK .............................................................................................. 24

9.1 Pump Discharge Pipework ......................................................................................... 24

9.2 Valve Applications .................................................................................................... 25

9.3 Valve Chamber ........................................................................................................ 26

10 PRESSURE MAIN ...................................................................................................... 26

10.2 Location of Pressure Mains ........................................................................................ 26

10.2.1 General ............................................................................................................ 26

10.3 Hydraulic Design...................................................................................................... 27

10.3.5 Velocity in Pressure Mains................................................................................... 27



10.3.6 Sizing of pressure mains ..................................................................................... 27

10.4 Design Pressures ..................................................................................................... 27

10.4.3 Surge ............................................................................................................... 27

10.6 Plastic Pipes ............................................................................................................ 27

10.6.2 Fatigue design for thermoplastics pipes ................................................................ 27

10.8 Pipeline Materials ..................................................................................................... 27

10.9 Pressure Main Valves................................................................................................ 28

10.9.1 General ............................................................................................................ 28

10.9.2 Isolating valves ................................................................................................. 28

10.9.3 Gas Release Valves ............................................................................................ 28

10.9.5 Scours.............................................................................................................. 29

10.10 Odour and Septicity Control ................................................................................... 29

10.10.1 Chemical Dosing ................................................................................................ 30

10.11 Receiving System ................................................................................................. 30

10.11.2 Discharge MHs .................................................................................................. 30

12 SUPPORTING SYSTEMS ............................................................................................ 31

12.1 Services ................................................................................................................. 31

12.1.2 Water ............................................................................................................... 31

12.1.3 Telephone/Telemetry Lines ................................................................................. 31

12.2 Materials Handling ................................................................................................... 32

12.2.1 Lifting equipment .............................................................................................. 32

12.3 Security .................................................................................................................. 32

14 DESIGN REVIEW ...................................................................................................... 32

Part 2: Products and Materials ............................................................................................... 33

16 PRODUCTS AND MATERIALS OVERVIEW ..................................................................... 33

16.6 Selection Guide for Pipeline Systems .................................................................... 33

Part 3: Construction ............................................................................................................. 33

19 GENERAL CONSTRUCTION ........................................................................................ 33

19.1 General ............................................................................................................ 33

22 Telemetry ............................................................................................................... 33

22.1 Compliance with Authorities, Statutes, Regulations and Standard ............................ 33

30 PIPE LAYING AND JOINTING ..................................................................................... 34

30.6 Marking Tapes ................................................................................................... 34

30.8 Bored Pipes Under Roads, Driveways and Elsewhere .............................................. 34

33 FILL ....................................................................................................................... 34



33.1 Trench Fill......................................................................................................... 34

34 CONNECTION TO EXISTING GRAVITY SEWERS ............................................................ 34

36 ACCEPTANCE TESTING ............................................................................................. 34

37 COMMISSIONING .................................................................................................... 35

37.3 Defects Liability Period ....................................................................................... 35

39 WORK AS-CONSTRUCTED DETAILS ............................................................................ 35

Appendix A – Sewage Pumping Station Design Checklist ........................................................... 36

Appendix B – Pre-Commissioning Checklist ............................................................................. 39

Appendix C – Commissioning Checklist ................................................................................... 40



Part 1: Planning and Design

1.0 GENERAL

1.1 Scope Additional requirements: This Code does not apply to low pressure pumping systems.

1.5 Planning and Design Responsibilities and Interfaces

Design responsibilities Additional requirements: The Designer should consider what investigation work is required and advise Western Water accordingly. The investigations may include:

• Geotechnical; • Survey; • Environmental; • Cultural heritage; • Land ownership and easements; • Odour and corrosion; • Condition assessments; and, • Others as required.

1.6 Sewer System Design Approach

Objectives of design Additional requirements: Pumping stations should include wherever possible:

• Full integration with Western Water’s telemetry system and SCADA system; • Be designed with minimisation of whole of life costs in mind including long term

maintenance/operation costs, power usage and resulting greenhouse gas production; • Meet current environment protection guidelines and regulations; • All materials and equipment are to have minimum 12 months warranty; • Have sufficient protection (cover to concrete reinforcement, epoxy coating, PVC lining etc.) to

provide a 100 year serviceability with elevated H2S levels; • Cleaning and removal of equipment to be achievable without entering the pump station; • A fall protection/fall arrest system as approved by Western Water; • Be capable of servicing all proposed and future catchment areas upstream of the proposed pumping

station. In addition, it is essential the developer carries out a proper assessment of this, and ensures that all proposed and future proposed catchments upstream of the proposed pumping station are incorporated into the design;

• Have sufficient emergency storage in accordance with Western Water’s requirements; • Designed to resist flotation due to high ground water levels;



• Have purpose designed odour control and/or ventilation system; • Minimise noise pollution; and, • Designed to withstand the impacts of bushfire at the location based on the Bushfire Rating of the

site as determined from AS 3959.

2 CONCEPT DESIGN

2.1 Life Cycle Considerations Additional requirements: 2.1.1 Package pumping systems Special written approval shall be obtained from Western Water for packaged precast pump wells and control systems. Such approval may only be granted for temporary and or minor pump stations.

2.14 Signage Additional requirements: Provide confined space signage at the pumping station, as shown in Figure 2.14.

Western Water will provide a station identification sign to be installed at the Pump Station.

2.17 Commissioning Plan

2.17.1 General Additional requirements: Prior to commissioning, all documentation outlined in preceding section should be forwarded to Western Water. In addition the pre-commissioning checklist (Appendix B) shall be completed and lodged 5 working days prior to the planned commissioning date. Notification of the upcoming commissioning must be made to the SCADA Coordinator 14 days in advance, to ensure that telemetry points are set up, and, the telemetry must be pre-commissioned in consultation with him to ensure that all alarms are being received at Western Water’s Communications Centre.

The pump station will not be commissioned /deemed operational until all documentation has been provided together with: • Plant data sheets. (2 hard copies, 1 digital copy) • As constructed drawings for Civil, Mechanical & Electrical (SPS & RM). (2 hard copies, 1 digital) • PLC program on memory stick / CD. (2 hard copies, 1 digital) • Job Safety Analysis for all routine maintenance tasks to be performed at the SPS. • Two copies of the operational and Maintenance manuals inclusive of pump system curves. • Copy of concrete compressive strength and slump test results. • Factory pump test results • Switchboard factory & site acceptance test certificates completed and signed. • Digital drawings shall be in AutoCAD (.dwg) format. & PDF (.pdf) adobe acrobat format.

Figure 2.14 Confined Space Sign.



3 GENERAL DESIGN

3.2 Design Tolerances Replace the last paragraph with the following: Horizontal alignment shall be referenced to the MGA coordinate system, and where possible, to local property boundaries. Levels shall be referenced to AHD.

3.7 Easements Additional requirements: Pressure mains are not permitted in private property unless otherwise approved by Western Water for rural properties. The location of all pressure mains shall be agreed with Western Water prior to completing the final design. New Clause:

3.14 Bushfire Requirements The design shall comply with Western Water’s Bushfire Requirements for Asset Protection. These requirements apply to the site selection, design and operational aspects for all new assets to improve their resistance to bushfire attack from burning embers, radiant heat, flame contact and a combination of the three attack forms.

4 MATERIALS DESIGN

4.2 Corrosion Protection

4.2.2 Concrete surfaces Additional requirements: The internal surface of the pumping station should be epoxy coated, however Western Water may agree to omit the epoxy coating in temporary pumping stations or pumping stations that are not expected to be attacked by high levels of sewer gases. Epoxy coating should not be omitted without prior approval from Western Water. All interior surfaces of the wet well, valve chamber, emergency storage and inlet MH (including the underside of any concrete access covers) should be coated with an epoxy lining system. The Super Epoc epoxy coating system (as provided by Peltos), or any approved equivalent epoxy lining system should be specified. Application shall be in accordance with the supplier’s recommendations.

4.2.3 Metallic materials Additional requirements: All metalwork in the pump well and valve chamber should be corrosion protected or of metal type which is not adversely effected by raw sewage (i.e. grade 316 stainless steel or grade 316L for fabricated items).



The use of dissimilar metals within the pumping station pump well should be avoided. If use of dissimilar metals is unavoidable, measures should be taken to negate the effects of galvanic corrosion of equipment. Such measures as insulation between dissimilar metals or the use of sacrificial anodes at strategic points within the pump well should be considered. However these options are to be implemented only after consultation with an expert in the field of galvanic corrosion.

5 PUMPING SYSTEM

5.2 Inlet MH

5.2.1 Site selection Additional requirements: The following additional factors should be considered when selecting the location of a pumping station: • Potential likelihood of future development, and

ability of the sewage pump station to service this future development;

• Emergency flow relief; • Depth of incoming gravity sewer as this will

influence the pumping station depth; • Proximity to rising main discharge point should

be as close as possible to minimise the rising main length;

• Pump station is not to be located under power lines so as to cause lifting operations to conflict with the power lines “No Go“ zone;

• Sites should have available access and consideration should also be given to construction and maintenance requirements (including maintenance vehicles and education trucks);

• Stormwater drainage of the site to eliminate any flooding of the site for a 1:100 year storm event; • Aesthetics, including landscaping and screens; • Land ownership; • Landscaping; • Stakeholder requirements; • Water and power supply; • Noise; and, • Odour control and ventilation.

5.2.5 Site layout and access Additional requirements and sub-section: The site must be accessible by vehicles by means of an all-weather access road. The nominated vehicle for the site is an 18,000L eduction tanker (semi-trailer). The Designer shall also consider the safe access into and out of the site from the existing carriageway.



The access road shall be constructed from compacted gravel unless otherwise specified. Also the pumping station shall be located such that cranes operating on site are clear of overhead electrical cables in accordance with the “No-Go Zone” regulations. If the pumping station is in an area as yet undeveloped, an all-weather access track shall be provided including hard standing area and water supply taking into consideration of future stage development. If the sewage pumping station works are being carried out by a developer, these access works shall also be carried out by the developer. The layout of the pumping station and other features must ensure that the available space for maintenance purposes is maximised. Bollards, comprising 1.50m high circular concrete filled or equivalent, are to be fixed with suitable fasteners to prevent vehicles driving over the top of any belowground structures.

5.2.5.1 Top Slab

A concrete top slab should be all one level and incorporate well covers, storage area for removed covers, electrical cabinet and valve pit. The slab should not to be located in an area that would be subject to local flooding. All water from surrounding area is to drain away from roof slab. Any access points into the wet well through the top slab, should be provided with watertight covers which are flush in level with the top slab to eliminate tripping hazard.

5.3 Inlet MH

5.3.2 Design Delete paragraph 3 – step irons/ladders are required in the inlet MH.

5.3.3 Pumping station wet-well isolating valve New paragraph at start of clause: Valve closing direction shall be as outlined in 9.2.1 of this standard. All knife gate valves shall confirm to the following criteria: • Knife gate valve to be Bi-directional with non- rising stem, Grade 316 SS. • Component and Grade 316 S.S. extension spindle extension spindle to be supported by Grade 316

SS support brackets at suitable spacing. Valve to be supplied complete with valve key cover box and all nuts, bolts and washers and gaskets for insertion between flanges, drilled off centre; and,

• The mounting flange must be ductile iron or fabricated from grade 316L stainless steel.



5.4 Wet-Well Design

5.4.1 General New paragraph at start of clause: Wet-wells should be purpose built cast in-situ concrete structures. Alternative proposals shall require prior approval from the Western Water.

5.4.4 Control levels Replace Table 5.1 with the following:

TABLE 5.1 DEFAULT CONTROL LEVELS

Level Description

Duty pump cut-out

Set in accordance with the heights corresponding to the cut-in/cut-out volumes. Should also be set to be 100mm above the minimum submergence level recommended by the pump manufacturer as a factor of safety.

Duty pump cut-in Set at least 150mm below the incoming sewer invert level

Standby pump cut-in Set at least 600mm above the duty cut-in level

5.4.6 Benching New sentence at end of paragraph 1: The maximum allowable grade of the benching shall be 30o where practical.

5.4.7 Washers Replace clause with the following: To reduce the frequency of wet-well cleaning and the formation of H2S, all wet-wells shall be fitted with an approved wet well washer system. The washer is to be controlled by a PLC to run at appropriate intervals to achieve a total of 20 minutes running time per day. A backflow prevention device must be installed to the water supply for the wet well washer. Potable water should only be used for well washing if recycled water is unavailable.

5.5 Wet-Well Ventilation New paragraph at start of clause: The Designer shall investigate the need for natural or forced ventilation. Consideration should be given to the expected odour emissions and corrosion affects as a result of sewer gas accumulation, venting and treatment.



5.6 Overflow Containment

5.6.2 Emergency Storage

5.6.2.2 Configurations

New paragraph and table after paragraph 1: Pumping stations shall be provided with a minimum emergency storage to contain sewage inflows at the rate of PDWF for a as shown in Table 5.2. Western Water has based these requirements on response times to respond and act on a high level alarm.

TABLE 5.2 MINIMUM EMERGENCY STORAGE VOLUME

Pumping Station Size (at ultimate development) Minimum Emergency Storage Volume

PDWF of less than 5L/s 2 hours at PDWF

PDWF equal to or greater than 5L/s 3 hours at PDWF If the pump well overflow is likely to pose potential or high risk as indicated in Table 5.3, the pumping station should be considered sensitive and alternative design exceeding that specified in this procedure should be adopted.

TABLE 5.3 RISK ASSESSMENT FOR SEWER OVERFLOWS

Parameters Low Potential or Risk High Potential or Risk

Environmental values of receiving environment*

Water used for Industrial or Agricultural purposes only

Water used for Drinking, Recreational - Primary Contact (swimming)/Secondary Contact (fishing/boating) or requires Aquatic Ecosystem Protection

Water Quality Objectives** Low degree of compliance High degree of compliance

Overflow Characteristics Infrequent, low volume, short duration

Frequent, high volume, long duration

Physical Factors High dilution and dispersion rate

Low dilution and dispersion rate (e.g. head waters in a stream)

Overflow Quality Domestic source Industrial source *consistent with State Environment Protection Policy (Waters of Victoria) - SEPP (WOV) ** refer Table 1 SEPP (WOV) Replace paragraph 2 with: Typical emergency storage configurations are provided in Figures 5.1, 5.2, 5.3 and 5.4. The typical configuration shown in Figure 5.4 is not preferred as the emergency storage cannot be used as temporary operational storage in the event the wet-well is taken off-line. Emergency storage volume shall be calculated between high-level alarm and the overflow weir crest level and shall be provided in:

a) the wet-well, and/or



b) any required separate storage structure.

Any storage available in the reticulation system shall not be included in the calculation of emergency storage volume. Add new paragraph at end of clause: Should an additional emergency storage tank be required the following will need to be considered and discussed with Western Water: • The installation of an automatic or manual tank washing system; • Open or closed top; • Type and arrangement of tank (pipe, tank etc.); • Accessibility for maintenance and eductor truck hoses. (e.g. no. of covers required); • Wash-down and cleaning requirements; • Ventilation requirements; • Filling mechanism (it is preferable for storage tank to be filled from the inlet MH or upstream so

that the storage is able to be used as temporary storage in the event that the wet well is taken off-line);

• Level monitoring requirements; • Drainage. (It is preferential for the storage tank to receive flows and drain by gravity-not pumped); • Fail safe alarms to be accessible from the outside; • Be resistant to H2S attack; and, • Be trafficable where not an open top storage.

5.6.4 Emergency Relief System Replace paragraph 1 with: Pumping stations shall be provided with an emergency relief system (ERS) which shall overflow from the emergency storage wherever practicable or alternatively, from the inlet MH (Refer to Standard Drawing SPS-1404). The emergency relief system shall provide a controlled spill path downstream of the pumping station in the event of an extended pump failure or for a storm event resulting in inflows exceeding the capacity of the pumping station. The Designer shall undertake hydraulic analysis of the system to ensure that spills occur in a controlled manner as intended and that there is no possibility of overflow at upstream MHs, property drains, etc. Higher head and level of surcharge is caused by losses in the system, e.g. losses due to flap gate and friction. An additional head safety factory of 0.5m is generally used to allow for these losses. New paragraphs at end of clause: The emergency relief system shall be designed in accordance with the provisions of the Sewerage Code of Australia WSA 02-2002-2.3 Melbourne Retail Agencies Edition. The Designer shall contact the receiving waterways controlling authority (such as Melbourne Water) and obtain approval for the new asset. Where emergency overflow relief pipework discharges into an unformed drain, creek or water course, then the Designer should detail the hydraulic impact of 1 in 10, 1 in 20, 1 in 100 year storm events on the upstream sewerage system.



Provide a flap gate within the pipework system to minimise the backflow of stormwater if the creek level rises above the pipe outlet. An acceptable type flap valve is a Hume-King floodgate or Western Water approved equivalent

5.7 Ladders and Platforms Additional Paragraphs: Provide safe access for confined space access when necessary. The Designer should minimise the requirement for person entry. Ladders and platforms for safe entry are required for both the wet-well, valve chamber and any separate emergency storage. The ladders and platforms shall be designed to comply with AS1657. Ladders shall be fitted with extendable stanchions and be fabricated from annealed stainless steel grade 316L or GRP.

5.8 Wet-Well Access Covers Additional Requirements: Pump well covers providing access to the wet well and/or valve pit should have minimum clear access of 900mm x 750mm. The covers should be of sufficient size and orientation to facilitate installation and removal of equipment and plant as well as personnel access to the pump well and valve pit. If staging requires a change of pumps, or if the catchment is anticipated to grow beyond the current design parameters, then the access covers shall be sized to accommodate the maximum size pump that the wet-well can accommodate. Covers are to be gas tight and be lockable via clasp and staple. If covers are to carry vehicular or similar traffic loading gatic covers are to be installed. Under these circumstances bollards may not be required. Covers shall comply with AS 3996 “metal access covers, road grates and frames”. All covers to maintenance holes shall be circular unless otherwise approved by Western Water (wet well and valve pit covers may need to be square or rectangular for practical reasons).

5.9 Safety Systems Additional Requirements: A safety system comprising a properly designed hinged mesh cover or other Western Water approved system shall be provided to prevent staff falling into the well when the access covers are open for inspection. Alternate safety provisions will be considered upon approval by Western Water. An example of a suitable fall protection system for a small submersible SPS is the Clancy’s Lane SPS in Woodend or Cityview SPS in Sunbury. A permanent tubular handrail system shall be provided around the opening to the pump well.



6 PUMPING SYSTEM

6.1 Staging New paragraphs: Any proposal to install pumps in series shall require the written approval of Western Water. The Designer shall provide evidence that an energy efficiency analysis has been carried out. The energy efficiency analysis shall consider the use of multiple duty points over a pumping station’s life, staging of pump capacity, use of variable speed drives or multiple duty pumps where the benefits of these can be demonstrated and other methods to minimise energy use.

6.2 Hydraulic Design Insert new sentence at the end of paragraph 3: Pumping stations shall have the capacity to transfer all peak wet weather flows from a 1 in 5 year ARI event unless otherwise advised by Western Water. Additional information about a catchment’s characteristics may warrant an increase in the pumping station capacity (small catchments have less attenuation and may warrant higher factors).

6.2.1 Design Flow Estimation

6.2.1.1 New Catchment

All new catchments where no additional information is available will assume that each domestic property discharges the following ADWF: • 555 L/lot/day for existing lots prior to 2012 • 450 L/lot/day for new/future lots after 2012 (based on population of 2.5 persons/lot) Include the following specific information for design flow estimation in Western Water’s area: For estimation of design flows in Western Water’s area, use the values specified in Table 6.1 for catchments where these values are known or expected to vary, they adjusted accordingly.

TABLE 6.1 DESIGN FLOW ESTIMATION EXAMPLE PARAMETERS

Parameter Value

PortionWet (% of sewer network below groundwater table) 35%

PortionImpervious (% of gross plan area impervious) 90%

Soil aspect, Saspect 0.8

Network defects and inflow aspect, Naspect 0.4

Containment ARI (years) 5

I1,2 (from design rainfall isopleth – AR&R, Volume 2) 19mm/h



Other users (e.g. industrial/commercial) are to be individually assessed. For all new/upgraded pumping stations, the flow estimation method for undeveloped areas as outlined in WSA 02-2002 MRWA should be used for calculating design flows.

6.2.1.2 Existing Catchment

The SPS upgrade for an existing catchment will be determined using a mix of catchment flow monitoring and design storm events.

6.4 Pump Selection New paragraph: All pumps shall have an engraved ID plate will be fixed to inside of the pump opening in the well identifying the pump, which coincide with the pump control and SCADA system, such as “PUMP 1”. A spare ID plate for each pump shall be provided within the control cabinet.

6.6 Submersible Pumps

6.6.6 Pumpset lifting equipment

New paragraph after paragraph 3: Guide rails and chains shall be grade 316 Stainless Steel, be fully supported and provided in one continuous length. The lifting chain offered for pump removal must comply with Statutory Authorities requirements for industrial lifting. The lifting chain shall be supported and retained by a small diameter stainless steel cable static line between the top of the chain and the top of the well adjacent to ground level, to retrieve the chain if dropped.

6.8 Pump Starters and Variable Speed Drives

6.8.1 General

Delete clause and replace with the following: All submersible sewage pumps shall use electronic soft starters incorporating line and bypass contactors. It shall also include an isolation switch (for insulation resistance testing) on the dead side of the soft starter, used to isolate to megger pumps. A label is to be fitted to warn not to “megger” the pump sets before disconnecting them via the isolating switch. Variable speed drives should only be considered where a variable flow rate or pressure is required by the pumps to maintain a consistent outflow or level in the wet well, and in such instances shall be approved by Western Water.



7 POWER SYSTEM

7.1 General Additional requirement: The Designer shall assess the power supply available to the site, and make arrangements to connect to the existing power supply, or apply for any necessary upgrade to the power supply, with the relevant power supply authority.

7.2 Power Supplies

7.2.5 Emergency Power

Additional requirements: Where specified by Western Water, a pumping station shall have a permanent on-site generator. All pumping stations are required to have a plug connection for an emergency mobile generator in accordance with clause 7.2.7.

7.3 Power and Control Cubicle

7.3.1 Design

Additional requirement: The cabinet design should, where practicable, include the following: • Located to provide a safe working area adjacent to covers, or approved location; • Designed to withstand the impact of bushfire at the site (Bushfire Rating as determined from

AS3959); • Made from minimum 3mm thick marine grade aluminum or approved equivalent; • All Internal doors, panels, escutcheons and gear trays shall be made from at least 2mm sheet steel; • All exterior doors to be fitted with neoprene sealing strips; • Manufacture of cabinet ventilation to accommodate heat load from internal devices, all vents shall

have insect screens and dust proofing; • Weatherproof and provided with a rain hood where practicable; • Gland plates aluminum 3mm (unpainted) and seal with Neoprene gaskets; • Powder coated interior finish to all doors, panels, escutcheons, gear trays and internal surfaces to

be gloss white, Wilderness Green colour (Colourbond palette) for external surfaces to AS2700, or approved equivalent;

• Hot dipped galvanised plinth; • Door is to swing open 180o and be capable of being fixed at a 90 o opened position; • All external doors to be fitted with door limit switches to detect entry to cabinet via RTU/PLC; • Does not exceed 1500mm in height above top of slab; • Fitting of stainless steel labels with chrome screws to all outer doors to identify internal sections; • Fitting of Traffolite labels with chrome screws to all inner doors to identify internal sections and

equipment • Lockable by means of Western Water approved locking system; and, sufficient space to

accommodate the following equipment;



§ Supply Company meter;

§ AMP meters;

§ Hour run meters;

§ Switchgear;

§ Control circuits including pump control system and circuit breakers;

§ Telemetry equipment;

§ Alternative power supply wiring;

§ Electric wiring so as not to present a ‘birds nest’;

§ If not provided with SCADA (e.g. small SPS), space of approx. 600 mm x 500mm shall be provided for a future SCADA unit with set up for easy connection of SCADA equipment;

§ A lockable weatherproof external connection to the switchboard for connection of a portable generator to Western Water’s satisfaction, and,

§ A polarity switch - The polarity shall be capable of reversing the polarity of the alternative electrical supply to avoid the possibility of pumps running backwards.

• Height of meters such as AMP meters and hour run meters shall be located at eye height so as to avoid the need to bend down to read these;

• Cabinet has separate doors for the power company meter with a suitable power company lock; and • Cabinet to include document pocket for site electrical drawings and manuals.

8 CONTROL AND TELEMETRY SYSTEM

8.3 Pumping Control

8.3.1 Control design

Delete paragraph 4 and replace with the following: In a two-pump station (i.e. one duty-pump and one stand-by pump) with a PDWF (at ultimate development) of less than 5L/s an interlock shall prevent both pumps from running simultaneously, on both automatic and manual control. For larger pump stations with a PDWF (at ultimate development) equal to or greater than 5L/s dual operation of the duty-pump and stand-by pump stall be enabled. In this instance the stand-by pump shall start once the stand-by pump cut-in level is reached regardless of whether the duty-pump is operating or not. Additional requirement: The control of the pumps shall be such that on failure of the RTU to perform the pumping function the high level float shall start the pump operation as long as not manually overridden at the switchboard.



8.3.2 Control switches

Delete clause and replace with the following: Each pump shall be controlled at the switchboard control panel by a three way selector switch (Automatic, Off, Manual) • Automatic Enables control of the pump from the RTU or float control. • Off Disables operation of the pump.

To enable isolation of the pumps during routine maintenance of the pump station (i.e. to prevent accidental startup of the pumps by accidentally tripping the level controls).

• Manual Overrides the pump normal start triggers and forces the pump to operate.

8.3.3 Control systems

Additional requirement: The design of the general operation of most pump stations should to be controlled by a Series 2 Kingfisher RTU using standard parts as used by Western Water. The design of the control system monitoring of operational status, level status of the pumping station is to be displayed on a Proface Screen (minimum 5.7” HMI) installed in the switchboard for maintenance and control set points for the sewer pump station. The location and orientation of the display screen should consider the incoming direction of any bright sunlight during the day. For systems with RTU installed the following signals are recommended to be included in the design: • Mains Power Monitoring; • Control power health; • Battery Status (Charger Healthy and Battery Low); • Access Doors Closed; and, • Wet Well Level (Analogue Signal).

Where possible remote resets for any motor or drive in the control circuit is recommended to be designed to be able to be reset from three sources: • RTU / SCADA Remote Reset; • Autodialler Remote Reset Output; and, • Local Panel Reset Button.

The control wiring on any non RTU site is to be designed to allow easy connection to Western Water’s SCADA system via an RTU in the future.

8.3.5 Pump starts and interlocks

Delete paragraph 1 and replace with the following: Each pump circuit for a pumping station with a PDWF (at ultimate development) of less than 5L/s shall incorporate an interlock to prevent the pumps operating simultaneously and to limit the load on the local power supply. For larger pump stations with a PDWF (at ultimate development) equal to or greater than 5L/s the interlock is not required and dual operation of the duty-pump and stand-by pump stall be enabled.



8.5 Alarm, Status Monitoring and Control Telemetry

8.5.2 Reliability

Additional requirements: Provide an Edac autodialler 700 series with 24 hour battery backup and a land line* with the following alarms/reports set to call Western Water’s emergency contact number verified by Western Water along with an identification name for the pump station: • Alarm 1 Pump failure; • Alarm 2 Phase Power failure; • Alarm 3 High level alarm; • Alarm 4 Phase fail alarm; • Report 5 Well level is: report; • Report 6 ERS level is: report; • Report 7 Pump flow is: report; • Alarm 8 Control/DC power fail alarm; • Alarm 9 Overflow alarm to emergency storage; • Alarm 10 Fail to pump alarm; • Alarm 11 Duty and stand-by pumps both operating alarm; • Alarm 12 ERS overflow alarm; • Alarm 13 Emergency fail safe alarm; • Alarm 14 RTU/PLC fail alarm; • Alarm 15 Loop fail alarm; • Alarm 16 Generator running alarm; • Alarm 17 Generator fault alarm; • Report 18 Pump running report; • Output 19 RTU reset output.

*Western Water may consider a mobile telephone service in remote locations.

All signals where possible that are connected to the autodialler shall be wired directly from the relay logic and not via a RTU or PLC, unless the signal is a status of the RTU/PLC or information from a remote site via a communications link. The Designer should confirm the requirements for the pumping station to connection to Western Water’s SCADA system, for pumping stations with a PDWF equal to or greater than 5L/s connection to SCADA system is required, with pumping stations smaller than this not normally required to connect to SCADA. New sentence: All identified critical spill points including ERSs shall be also fitted with an independent ‘Fail Safe’ alarm to provide early detection of system blockages, equipment failure or hydraulic overloading that if left unreported have the potential to result in a sewage spill. The Fail Safe alarms shall be fully independent of any other monitoring and be provided with dedicated back-up power mounted in the main board. A space 25mm conduit shall be provided for the Fail Safe Alarm cable. The Fail Safe Alarm



equipment including floats, instruments, antenna, etc. will be supplied by Western Water. The alarm shall be set at the level determined by Western Water Operations.

8.5.3 Alarm creation function

Replace Table 8.1 with the following: TABLE 8.1

DEFAULT ALARM LEVELS

Parameter Description

Low level alarm Set at the snort level of the pumps

High level alarm Set at 300mm above stand-by cut-in level but never above the inflow emergency alarm

ERS Overflow alarm Set at the ERS spill level

Overflow to Emergency Storage Alarm Set at the spill level to emergency storage

8.6 Telemetry Hardware

8.6.2 Software

Additional requirements: The Designer of the RTU program should adopt an approach that uses similar code to systems already in use across Western Water. (Where possible use Western Water Standard SPS code) RTU registers should be used in accordance with similar site to enable easy connection to Western Water’s SCADA system. The Designer should maintain a list of used registers in the project detailing the address and function of each register to allow for easier future modifications.

8.7 Operating Levels and Default Settings

8.7.2 Cut-in and cut-out levels

Replace last 2 paragraphs with the following: The stand-by pump cut-in level shall be at least 600mm above duty pump cut-in level. The level of pump controls shall be set at least 200mm apart.

8.7.3 Alarm levels

Replace first 2 paragraphs with the following: The high-level alarm shall be set at least 900mm above duty pump cut-in level (300mm above stand-by pump cut-in level). An inflow emergency alarm is not required.



8.8 Equipment and Devices

8.8.1 General

Additional requirement: Refer to Western Water for selection of level sensors, i.e. brands of hydrostatic pressure level sensors preferred and control system rather than level switches etc.

8.8.2 Flow measurement

Delete paragraph and replace with the following: For pumping stations with a PDWF less than 5L/s, provide an electromagnetic flowmeter at the end of the rising main which shall provide continuous monitoring of flows. To enable correct operation of the flowmeter, the rising main should be designed to be running as pipe full at this location. For pumping stations with a PDWF equal to or greater than 5L/s, the need for additional flow monitoring should be considered and agreed with Western Water. This may include an additional magnetic flowmeter at the start of the rising main (to compare to the flow at the end which can assist in detecting leaks in the rising main) and/or a flow monitor on the inlet sewer to the wet well. All flow meters should allow continuous monitoring of flows. The location of flowmeters and all cabling is to be included in the as constructed information with a location plan fixed to the inside of the control cabinet.

8.8.12 Emergency stop-buttons

Additional paragraph: Emergency stops are typically not included on the external/non-secure pump stations and should be considered on larger pump stations that are secure.

9 WET-WELL PIPEWORK

9.1 Pump Discharge Pipework

9.1.1 General

Additional requirements: Any vertical pipework shall be designed with intermediate supports.

9.1.3 Type

Additional requirements: Internal pipework shall be Stainless Steel (SS) grade 316, Ductile Iron epoxy lined (DIEL) or Mild Steel Epoxy Lined (MSEL) or approved equivalent. However uPVC pipework within the pump station is not permissible. Polyethylene (PE) pipework (PE100 and minimum PN12.5) or ABS may be accepted as an alternative for DIEL pipework, only after prior approval from Western Water.



DIEL/SS/MSEL flanged pipe shall be used for cast-in pipe pieces. PE or ABS pipe is not permitted to be cast through concrete water retaining structure walls.

9.2 Valve Applications

9.2.1 Isolating valves

Add new paragraph after paragraph 1: Valve closing direction shall be as shown in Table 9.1. Spindle caps on clockwise closing valves shall be painted red to indicate clockwise closing direction.

TABLE 9.1 WESTERN WATER VALVE CLOSING DIRECTIONS

Area Sewer Valves Water Valves Sunbury, Diggers Rest, Lancefield Clockwise closing Anti-clockwise closing Gisborne, Woodend, Riddells Creek Clockwise closing Anti-clockwise closing Melton Clockwise closing Clockwise closing Bacchus Marsh Anti-clockwise closing Anti-clockwise closing All sluice valves shall conform to the following criteria: • Meet the requirements of AS 2638 Gate valves for waterworks purposes; • Shall be a minimum Class 16; • Shall have non-rising spindles; • Shall be resilient seated; • Shall be flange type drilled off centre in accordance with AS 4087, Metallic flanges for waterworks

purposes; • Shall terminate with a stem cap and shall be key operated, unless specified otherwise; • Have internal and external protective coating using an approved thermal-bonded coating; • Where specified hand wheels shall be manufactured from ductile cast iron. They shall be sized so

as to unseat and seat the valves under all likely service conditions using a rim pull force on the hand wheel of less than 40 Newton;

• Hand wheels shall be painted with 2 coats of epoxy enamel; and • Extensions shall be bracketed to internal walls (making sure they are free to operate).

9.2.2 Non-return valves

Add new paragraph after paragraph 1: All non-return valves shall confirm to the following criteria: • Non return valve are to be swing check type (full); • Minimum Class 16; • Manufacture in accordance with AS4794; and, • Ductile iron valves may be used subject to internal and external protective coating suitable for

water industry purposes and direct contact with sewage.



9.2.3 Scour/Emergency by-pass connection

Additional requirement: Provide a camlock fitting on the delivery pipework within the valve chamber to allow a portable high suction pump to be used in the event of an extended power failure.

9.3 Valve Chamber

9.3.1 General

Replace paragraphs 1 and 2 with: All pumping stations require a valve chamber to house the valves, scour and emergency bypass adjacent to the wet-well. Direct burial of these valves and appurtenances is not permitted. Valve chambers shall be cast in-situ concrete unless otherwise approved by Western Water.

9.3.2 Design

Additional requirements: Operation of the isolation valves and scour valve is not required from the surface. The wet-well roof slab shall incorporate the covers of the valve chamber unless otherwise approved. The valve chamber covers shall be large enough to enable crane access to remove valves for maintenance purposes. For valves greater than DN150mm, removal must be able to be carried out as a “direct lift” operation. The valve chamber drain back to the pump-well shall be fitted with a Hume-King Flood gate or approved equivalent. A water seal is not required. The depth of the valve chamber shall be the minimum necessary to accommodate the valves while providing the minimum cover to the rising main in the chamber.

10 PRESSURE MAIN

10.2 Location of Pressure Mains

10.2.1 General Replace clause with the following: The preferred location for pressure mains is within Water Agency owned land and road reserves. Pressure mains are not permitted in private property unless otherwise approved by Western Water for rural properties. The location of all pressure mains shall be agreed with Western Water prior to completing the final design. Pressure main locations shall be identified with relevant posted signs. Signs are to be erected at: Figure 10.3 Pressurised Sewer

in Vicinity Sign



• Change of direction; • At fittings along the pipeline; and • Maximum 500m spacing.

Western Water will provide the signage to be installed at the developers/contractors cost. The sign to be provided is detailed in Figure 10.3. The sign shall be connected to the post using self-tapping stainless steel screws. Posts shall be made from green recycled plastic, with signs attached.

10.3 Hydraulic Design

10.3.5 Velocity in Pressure Mains Replace 2nd last paragraph with the following: The maximum allowable of velocity of flow in the pressure main shall be 2.5m/s.

10.3.6 Sizing of pressure mains Additional requirement: The reduction in pipe diameters along the pressure main is not acceptable.

10.4 Design Pressures

10.4.3 Surge Additional requirement: The Designer shall carry out a surge analysis to protect against actual surge pressures for all operating scenarios including power outage, sudden pump stoppages, etc.

10.6 Plastic Pipes

10.6.2 Fatigue design for thermoplastics pipes Additional requirement: The Designer shall carry an analysis of the impact of fatigue over the design life of the pressure main where thermoplastics pipes are proposed. The Designer shall provide Western Water with the results of this analysis to support the selection of an appropriate class of pipe.

10.8 Pipeline Materials Additional requirement: The designer shall carry out the materials assessment and recommend the preferred rising main material. Only standard size and approved pipework shall be used. If PVC is specified it shall be RRJ and minimum class 16. All non-metallic pipes shall be installed with a detectable marker tape.



Pressure mains must comply with colour and marking requirements of the relevant WSAA Purchase Specification to differentiate pressure sewer mains from potable water and recycled water mains. These colours are currently PVC pipe to be coloured cream and PE pipe coloured black.

10.9 Pressure Main Valves

10.9.1 General Additional Requirements: All valves shall be installed with marker posts defining sewer markings. On street markings shall also be provided in the vicinity of a road. The designer shall consider bypass pumping arrangements that may be required during operation and maintenance of the pumping station, including: • Rising main tapings should be fitted with down turned copper tails to prevent accidental discharge

at personnel. • Consider possible bypass arrangements around the existing storage, critical crossing and other

assets during the design. • Consider how the main can be drained and isolated for maintenance and how the system can be

kept in operation. • Consider whether duplicate rising main or critical crossings are necessary to reduce the risk of

spills.

10.9.2 Isolating valves Additional Requirements: Isolating valves shall be provided either size of rail and major road crossings.

10.9.3 Gas Release Valves Additional Requirements: Air valves are to be located at all ‘high points’ along the rising main and/or at intermediate points along long grades. The air release valve shall comply with WSAA standard WSA112-2002 “Sewage Air Release and Vacuum Break Valves”. Air relief valves shall be stainless steel combination air release valve for sewage. In determining the location of the air release valve the following factors are to be considered: • Proximity to properties; • Venting requirements and subsequent odour issues; • Aesthetics of vent; and, • Access for maintenance.

Any gas release valves located above ground shall be appropriately protected (e.g. cabinet, cage, bollards). Any below ground gas release valves shall be indicated using marker posts.



10.9.5 Scours Additional Requirements: Where a gravity scour is not practicable, a pump scour shall be provided at low points fitted with a 100mm female camlock fitting complete with lock-down cap to Australian Standards. In addition to low points, additional scour installations shall be provided on the rising main so that the maximum spacing between scour installations is 500m. The following considerations may be given to scour arrangements: • Consideration can be given to different types of configuration to allow contingency options. An

example of this, where practical is the provision of dual scours with in-line valves and an inspection-pipe-length at low points in rising mains, which allows maintenance works and condition assessment to be carried out, as shown in Figure 10.4.

• Consider pumping sewage at high velocities through the scour points, to re-suspend any settled solids in the rising main.

• Consider scour points at low point in rising main. Facilities for emergency bypass pumping should be provided on the scour line.

• Consider suitable configuration for installing a temporary pumping arrangement, to allow a short pipe piece to be removed and inspected.

Figure 10.4 –Concept of Typical Dual Scour Pit Arrangement and Short Pipe Inspection Piece

10.10 Odour and Septicity Control Add new paragraphs and section: The Designer shall consider the septicity of the incoming sewage and the impact this will have at air release points along and at the end of the rising main. This assessment shall be considered for all operating scenarios of the SPS and staged increase in sewage flows, to demonstrate whether odour control measures are required.



The Designer shall carry out and provide documentation on a predictive analysis of hydrogen sulphide generation at both the pump station and point of discharge. This should require analysis of sewage entering from the reticulation system. Odour emissions can be minimised by the use of careful design of the inlet structure together with the incorporation of well flushing equipment. Western Water requires a submerged inlet pipe to minimise release by hydrogen sulphide gas from the turbulence of inflows. Where there is no drop structure then turbulence is to be addressed in the design of the pump inlet structure.

10.10.1 Chemical Dosing If all possible design parameters have been addressed to minimise the septicity of the sewage in the pump station and rising main, and still a problem of septicity remains, it may be necessary to chemically dose the rising main, pump well, and / or the reticulation lines leading to the pumping station. Where chemical dosing is considered necessary to control septicity then the Designer should detail dosing options, available impacts, advantages and disadvantages, capital / operating costs associated with the dosing. Where it is considered necessary to dose chemical to control odour / septicity, the Designer should carry out an odour assessment. The odour assessment should detail chemical dosing options, impacts, advantages / disadvantages, operating / capital costs of all dosing options. The assessment should also include consideration of: • Chemical availability and cost; • Chemical handling issues; • Impacts of the chemical on the downstream recycled water plant process efficiency and/or

operation; • Potential impact of a build-up of chemical in the system; • Impacts of the chemical addition on the quality of recycled water produced at the downstream

recycled water plant, and shall ensure that under no circumstance shall the Western Water stated quality of recycled water be compromised; and,

• Instrumentation and control system to ensure that the dosing is carried out to optimise the amount of chemical used to manage the odour levels in the receiving sewer.

The Designer should liaise closely with Western Water on the proposed ventilation and odour dosing. The Designer should also consider the treatment of odours at the pumping station if necessary.

10.11 Receiving System

10.11.2 Discharge MHs Additional Requirements: All pressure mains shall discharge to a discharge MH (receiving structure). The maximum velocity before discharge to the receiving sewer shall be less than 2m/s unless otherwise approved by Western Water.



The receiving structure including the cover should have a protection system to minimise corrosion and should be vented. The internal surface of the discharge MH shall be epoxy coated unless otherwise approved by Western Water. The Super Epoc epoxy coating system (as provided by Peltos), or any approved equivalent epoxy lining system should be specified. Application shall be in accordance with the supplier’s recommendations.

12 SUPPORTING SYSTEMS

12.1 Services

12.1.2 Water Replace clause with the following: The pumping station shall be provided with a 20mm metered potable water supply with an inverted anti vandal hose bib in a separate below ground meter pit for wash down purposes with two spare tap keys left in the electrical control cabinet. A metered water property service of minimum 20mm and a static pressure of 20m head shall be provided to ensure the wet well can be flushed manually. The Designer shall detail the installation of backflow prevention devices. The device and the fire hose reel are to be housed within a separate section of the control cubicle. The hose shall be a Wormald Recess Mounted Fire hose reel or equivalent. It shall have 18m of 19mm PVC fire fighting hose complete with a brass jet type grip operation nozzle. The cubicle size is to be large enough to allow maintenance of the back flow prevention device. In all instances, if connection to Western Water’s recycled water system is available at the site, only recycled water shall be used for well washing. Where recycled water is adopted for well washing, a potable water connection shall also be made for hand washing purposes. Each service (potable water/recycled water) shall be clearly differentiated and marked as such on site. Any above ground recycled water pipework shall be clearly marked as “Recycled Water – DO NOT DRINK”. The Designer shall ensure that there will be no cross connections between recycled water and potable water systems.

12.1.3 Telephone/Telemetry Lines Additional paragraph: The site shall be provided with a dedicated land line for telemetry and communications. If provision of a land line is not possible, a telecommunication system via the mobile phone network may be considered by Western Water. In some cases where a mobile phone network connection is recommended as a temporary measure until such time as a land line is installed, the Designer should include the future land line requirements and ensure that all approvals for this connection are made.



12.2 Materials Handling

12.2.1 Lifting equipment Replace clause with the following: The designer shall consider how the pumpsets are to be removed from the wet well and refitted. Based on the size and weight of the pumpsets, site layout and surrounding area, the need for a permanent lifting gantry over the wet well shall be confirmed with Western Water

12.3 Security Additional requirements: Unless otherwise specified by Western Water, install a 1.8m high (min) cyclone fence which is powder coated green or black with 3 strands of barb wire on top. Provide padlock-locking device for access covers. Western Water will provide a Western Water common keyed padlock upon commissioning of the pumping station.

14 DESIGN REVIEW Western Water requires the Sewage Pumping Station Design Checklist (attached in Appendix A of this Design Guide) to be completed and submitted along with the design drawings for auditing purposes. New paragraph: Once the design has been completed, Design Drawings shall be submitted to Western Water for auditing purposes, accompanied by Western Water’s Sewage Pumping Station Design Checklist which shall be completed by the designer. In general, Western Water will audit designs in the order they are received. It is Western Water’s expectation that all designs submitted for auditing will comply with Western Water’s design standards and will match the information provided in the accompanying Sewage Pumping Station Design Checklist. Where discrepancies are found, the designer will be expected to revise the design drawings and/or checklist and submit them for re-auditing.



Part 2: Products and Materials

16 PRODUCTS AND MATERIALS OVERVIEW

16.6 Selection Guide for Pipeline Systems New paragraph: Pipe and other associated products used on Western Water sewerage works shall be approved Western Water products and materials. Written approval from Western Water must be obtained for any alternative pipe materials prior to their proposed use.

Part 3: Construction

19 GENERAL CONSTRUCTION

19.1 General New paragraph: The following emergency contact numbers are in place for Western Water’s on-call operations staff and applicable for all existing Western Water assets in these areas:

Towns Emergency contact numbers

Macedon, Riddells Creek, Woodend, Gisborne 0418 507 059

Sunbury, Diggers Rest, Romsey and Lancefield 0408 391 545

Melton, Bacchus Marsh and Rockbank 0412 844 281

22 Telemetry

22.1 Compliance with Authorities, Statutes, Regulations and Standard

New paragraph: The design and installation of the SCADA system shall comply with Western Water’s SCADA Standards.



30 PIPE LAYING AND JOINTING

30.6 Marking Tapes

30.6.2 Detectable marking tape

Replace 3rd paragraph with the following: Detectable marking tape shall be installed above:

a) all non-metallic pipelines;

b) all curved pipelines; and

c) at other locations as specified.

30.8 Bored Pipes Under Roads, Driveways and Elsewhere New sentence: A CCTV report shall be submitted at the completion of the work.

33 FILL

33.1 Trench Fill

33.1.3 Compaction of trench fill

New sentence: Flooding or jetting of fill materials in excavation is not permitted under any circumstances.

34 CONNECTION TO EXISTING GRAVITY SEWERS New paragraphs: Cut-ins to live sewers shall only be carried out by contractors accredited to work on live sewers. The contractor must have obtained a Works Approval and a Certificate of Entry from Western Water for the date and time of the sewer connection. These forms are available at www.westernwater.com.au. The contractor must provide all confined space entry equipment and staff in accordance with Occupational Health and Safety regulations current at the time, and provide appropriate bypass pumping arrangements and standby equipment prior to attempting a connection to a live sewer.

36 ACCEPTANCE TESTING Additional Requirement: Acceptance testing for new gravity sewers constructed as part of the Sewage Pumping Station works shall be undertaken in accordance with and Western Water Sewerage Design Standard: Supplement to WSA-02.2.3 MRWA and WSA-02.2.3 MRWA.

http://www.westernwater.com.au



37 COMMISSIONING

37.1 General

Additional Requirements: Prior to commissioning all documentation outlined in preceding section should be forwarded to Western Water. In addition the pre-commissioning checklist (Appendix B) shall be completed and lodged 5 working days prior to the planned commissioning date. Notification of the upcoming commissioning must be made to the SCADA Coordinator 14 days in advance, to ensure that telemetry points are set up, and, the telemetry must be pre-commissioned in consultation with him to ensure that all alarms are being received at Western Water’s Communications Centre.

The pump station will not be commissioned /deemed operational until all documentation has been provided together with: • Plant data sheets. (2 hard copies, 1 digital copy) • As constructed drawings for Civil, Mechanical & Electrical (SPS & RM). (2 hard copies, 1 digital) • PLC program on disk / CD. (2 hard copies, 1 digital) • Job Safety Analysis for all routine maintenance tasks to be performed at the SPS. • Two copies of the operational and Maintenance manuals inclusive of pump system curves. • Copy of concrete compressive strength and slump test results. • Factory pump test results • Switchboard factory & site acceptance test certificates completed and signed. • Digital drawings shall be in AutoCAD (.dwg) format. & PDF (.pdf) adobe acrobat format.

New section:

37.3 Defects Liability Period Unless otherwise advised by Western Water, the Defects Liability Period for all sewer works shall be 24 months.

39 WORK AS-CONSTRUCTED DETAILS

39.1 General

Additional Requirements: The following information is to be provided with the pump station prior to Western Water’s preliminary acceptance of the pump station.

• 1 hard copy and 2 electronic copies 1 in Microsoft Word format (.doc, .docx) and 1 in Portable Document Format (.pdf) of an operation and maintenance manual for the pump station, in accordance with Western Water’s requirements. A standard template and an example can be provided upon request.

• Paper and electronic Autocad (.dwg) and Portable Document format (.pdf) produced in accordance of ‘As constructed’ detailed plans.

• Asset list (Western Water can provide a template on request).



Appendix A – Sewage Pumping Station Design Checklist

Criteria Complete Comments

Wet Well

Minimum Design Capacity @ PDWF provided. In accordance with specification and drawings as approved by WW.

Computations for flotation confirm minimum Factor of Safety of 1.1. In accordance with specification and drawings as approved by WW.

Coating of concrete surfaces. In accordance with specification and drawings as approved by WW.

Top slab to incorporate all below ground structures. In accordance with specification and drawings as approved by WW.

Wet well shall be self-draining. In accordance with specification and drawings as approved by WW

Covers in accordance with specification and drawings as approved by WW.

Minimum wet well diameter complies. In accordance with specification and drawings as approved by WW.

Volume between Cut in Cut out levels comply. In accordance with specification and drawings as approved by WW.

Wet Well washers comply. In accordance with specification and drawings as approved by WW.

Concrete strength specified. In accordance with specification and drawings as approved by WW.

Clearance from overhead power lines. In accordance with specification and drawings as approved by WW.

Ladders comply with specification and drawings as approved by WW.

Penstock complies. In accordance with specification and drawings as approved by WW.

Pipework complies. In accordance with specification and drawings as approved by WW.

Pipe supports comply with specification and drawings as approved by WW.

Pump well inlet pipe complies with specification and drawings as approved by WW.

Computations for pump selection inclusive of NPV. In accordance with specification and drawings as approved by WW.

Approved pumps. In accordance with specification and drawings as approved by WW.




Emergency Relief System

Complies with specification and drawings as approved by WW.

Valve Chamber

Pit Accessible. In accordance with specification and drawings as approved by WW.

Pipe supports comply with specification and drawings as approved by WW.

Rising main tapings in accordance with specification and drawings as approved by WW.

Ladders comply with specification and drawings as approved by WW.

Operation of valves without need to remove cover. In accordance with specification and drawings as approved by WW.

Chamber is self-draining. In accordance with specification and drawings as approved by WW.

Closing direction of valves. In accordance with specification and drawings as approved by WW.

Pipework and fittings comply with specification and drawings as approved by WW.

Infrastructure

Water supply in accordance with specification and drawings as approved by WW.

Lighting in accordance with specification and drawings as approved by WW.

Access road in accordance with specification and drawings as approved by WW.

Bollards in accordance with specification and drawings as approved by WW.

Switchboard location complies with specification and drawings as approved by WW.

Termination of generator connectors complies with specification and drawings as approved by WW.

Telemetry mast complies with specification and drawings as approved by WW.

Site drainage complies with specification and drawings as approved by WW.

Bushfire requirements considered and included in the design.




Pump Energy Efficiency

Consideration of operating the pumps at maximum efficiency during average demand periods as opposed to during peak demand periods.

Consideration of multiple duty points over the useful life of the pump station

Consideration of the use of multiple pumps and combinations of variable and fixed speed pumps to minimise energy consumption

Rising Main

Minimum pipe class as per specification and drawings as approved by WW.

Computations verifying velocity complies with specification and drawings as approved by WW.

Discharge MH complies with specification and drawings as approved by WW.

Air valve complies with specification and drawings as approved by WW.

Scour Valve assembly complies with specification and drawings as approved by WW.



Appendix B – Pre-Commissioning Checklist

REQUIREMENTS BY CONTRACTOR The following checklist is required to be fully completed, signed and returned to Western Water before a joint commissioning is considered. STATION NAME:__________________________ STATION NO:__________________ • Supply Authority Power available. Yes No • Provision of sufficient water for all testing purposes. Yes No • Fresh water discharge flushing system operating as per design Yes No • Ancillaries (GPO’s, lightning etc.) tested and working correctly Yes No • Telemetry radio survey completed satisfactorily Yes No • Station telemetry point lists supplied Yes No • Established telemetry communications and verified inputs locally Yes No



Appendix C – Commissioning Checklist

Verification of as constructed levels and operation Note: Levels taken from well cover down

Setting/ Alarm Measurement Operational function (contractor to verify correct operation)

Spill alarm M Yes No

H/L back up pump 2 start M Yes No

H/L back up pump 1 start M Yes No

High level alarm M Yes No

H/L pump cut out/ Transfer M Yes No

Duty pump cut-in M Yes No

Duty pump cut out M Yes No

Low level alarm (indication only) M Yes No

Wet well level indicator Yes No

Level controller span 0-………………… M

Level controller datum MAHD Level settings according to design Yes No NA

Commissioning of Civil Works Item Complete Date / Initials

Management

Verify that Designer has provided all documentation. (as constructed details, operating manuals, test results etc.)

If NO then close audit.

Concrete

Verify that the concrete slab is flush with the finished surface level.

Verify that there is no damage to any exposed concrete surface.

Verify that the top slab does not affect the drainage of the site.

Verify that the surface dimensions of the top slab are in accordance with specification and drawings as approved by WW.

Verify that the below ground concrete structures are dimensionally correct and in accordance with specification and drawings as approved by WW.

Verify no leakage through the concrete structure.

Verify the verticality of the structure is within tolerance in accordance with specifications and drawings as approved by WW.



Item Complete Date / Initials

Verify that all chamfers are provided in accordance with specification and drawings as approved by WW.

Verify that the pump well benching has been provided in accordance with specification and drawings as approved by WW.

Verify that the specified coating to the walls has been applied in accordance with specification and drawings as approved by WW.(extent/coverage)

OH&S

Verify that ladder access to wet well meets OH&S requirements.

Verify that ladder access to valve chamber meets OH&S requirements.

Verify that all ladders are provided with the extension above the FSL.

Verify that the ladders have non-slip treads.

Have safety cages been specified

Verify that safety cages have been installed in accordance with specification and drawings as approved by WW.

Verify that adequate distance between wet well opening and switchboard is in accordance with OH&S requirements.

Verify that adequate set down areas for the covers has been provided in accordance with OH&S requirements.

Verify that no overhead cables restrict access via crane trucks.

Products & Materials

Verify that all products incorporated on the project are approved by WW

Verify that all markings as required by specification and drawings as approved by WW are visible on the covers.

Verify that the covers and frames are greased in accordance with the manufacturer’s requirements.

Verify that the interchangeable multi part covers have lifting lugs on the beams for removal and covers have clockwise lifting key holes.

Verify that WW approved penstock stuffing box is installed.

Pipes & Fittings

Verify that the valves are closing the correct direction (clockwise/anti-clockwise).

Verify that adequate supports have been provided for the valves.

Are valve extension spindles required.(includes penstock)

Are adequate supports provided in accordance with specification and drawings as approved by WW.




Verify that pipework has been provided to correct DN.

Verify that adequate supports for vertical pipework have been provided. (i.e. vibration not noticeable when pumps operating)

Verify that all gate valves operate through the full range and are left in the open position.

Verify that a flap valve has been installed on the valve chamber drain.

Verify that bleeders have been installed on the NRV’s

Verify that the specified pressure gauges have been installed in the valve chamber.

Verify that the WW specified coating for all valves has been applied.

Verify that the WW specified coating for the pipework has been applied.

Verify that the pipework for the incoming sewer is in accordance with the design drawings.

Verify that the specified bolting system on the flanges has been used.

Verify that all valves can be removed through the available cover opening.

Verify that uni-flanges have been provided to allow ease of removal of valves in accordance with specification and drawings as approved by WW.

Verify penstock installed as per specification and drawings as approved by WW.

Other Services

Verify that the water service has been fitted with an approved back flow prevention device and hose reel in cabinet.

Verify that all conduits through the top slab have been sealed to prevent odour escaping.

Verify that electricity is below ground, not above. Verify that the access track is in accordance with the specification and drawings as approved by WW.

Verify that adequate site drainage has been provided.

Verify that wet well washers have gate valves and regulators fitted

Restorations

Verify that the site restoration has been completed.

Testing.

Verify that pump well infiltration test passed.




Verify that pump draw down tests passed.

Verify the operation/commissioning testing of the pump station as well as the rising main.

Mechanical Equipment.

Verify that the guide rails comply with the specification and drawings as approved by WW.

Verify that the lifting chain complies with specification and drawings as approved by WW.

Verify that the Pump footstool has been secured to wet well floor with appropriate chemical anchors.

Are wet well washers specified approved by WW.

Verify that they meet the specification and drawings as approved by WW.

Electrical Equipment.

Verify that the Station Identification plaque has been fitted to the electrical cabinet.

Verify that the telemetry aerial has adequate protection in accordance with specification and drawings as approved by WW.

Verify that external lighting over the switchboard has been provided.

Verify that the WW locks fitted to switchboard are operational. Verify that quick link generator connectors are provided

Verify that both the telemetry and control equipment work.

Security.

Verify that the security fencing has been installed in accordance with specification and drawings as approved by WW.

Verify that WW keyed locks installed.

Have all NC items been resolved (including any raised as a result of this audit)

If YES Issue Acceptance of Works, and close audit

Will outstanding NC items impact on the ability to operate the pump/s

If YES then close audit (wait for NC items to be resolved)

Has Operations authorised the pumps to remain on.

If YES record the name of the person who authorised this. NAME………………………………….

SEWAGE PUMP STATION DESIGN STANDARD - · PDF fileSEWAGE PUMP STATION DESIGN STANDARD Supplementary Information to the WSAA Sewage Pumping Station Code of Australia WSA 04-2005-2.1

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