SECTION SEWERAGE AND COMMON EFFLUENT DISPOSAL (CED) RETICULATION

Transcription

1 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B SECTION SEWERAGE AND COMMON EFFLUENT DISPOSAL (CED) RETICULATION PURPOSE OF SECTION GENERAL PRELIMINARY SEWER CONCEPT PLAN TRUNK MAINS PIPES AND CLASS HOUSE CONNECTIONS SEWERAGE CED ALIGNMENT OF MAINS DEPTH OF SEWERS/CED LINES DESIGN CRITERIA - SEWERAGE GENERAL PIPE VELOCITY MINIMUM GRADES CAPACITY DESIGN CRITERIA - CED GENERAL PIPE VELOCITY MINIMUM GRADES CAPACITY MANHOLES GENERAL SPECIFIC COUNCIL REQUIREMENTS DROPS THROUGH MANHOLES SEWERAGE SCHEME LOCATIONS CED SCHEME LOCATIONS

2 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B PUMP AND LIFT STATIONS GENERAL PUMP DESIGN CRITERIA PUMP WELL CRITERIA SPECIFIC COUNCIL REQUIREMENTS PRESSURE MAINS PRIVATE PUMP STATION AND PRESSURE MAIN GENERAL APPROVED CONNECTION POINT PRIVATE PUMPS PUMP WELL CAPACITY AND OPERATION PRIVATE PRESSURE MAINS SPECIFIC REQUIREMENTS OVERFLOWS CONNECTIONS TO EXISTING MAINS (WORKS BY COUNCIL) EASEMENTS ENGINEERING DOCUMENTATION ENGINEERING DRAWINGS SPECIFICATION SUBMISSION OF ENGINEERING DRAWINGS/JOB SPECIFICATION CONSTRUCTION PROCEDURES AS CONSTRUCTED REQUIREMENTS TABLE LISTING 2.7A MINIMUM PIPELINE GRADES 2.7B EQUIVALENT POPULATION DENSITIES 2.7C PUMPWELL STORAGE DURING BREAKDOWN

3 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B SECTION 2.7 SEWERAGE PURPOSE OF SECTION The purpose of this Section is to provide Developers and their Consultants with Council's general criteria to ensure that:- Adequate consideration is given to the health and environmental issues that relate to the provision of sewer infrastructure The reliability, safety and effectiveness of Council's sewerage reticulation is maintained Sewerage reticulation is of adequate quality to minimise maintenance costs GENERAL These Guidelines provide "deemed to comply" criteria and Council's minimum standards for Developments encompassing common effluent disposal schemes and sewerage reticulation including works required to join with existing and adjoining sewerage reticulation systems. All common effluent disposal schemes and sewerage reticulation schemes shall be designed in accordance with the following provisions:- WSAA Code of Australia Sewerage WSAA Sewerage Pumping Code of Australia The current Planning Guidelines for Water Supply and Sewerage (DNR&M) Council's general criteria as set out in these Guidelines and Council's Standard Specifications and Drawings AS3500 National Plumbing and Drainage Code as applicable. Council's Land Development Guidelines and Standard Specifications and Drawings shall take precedence over the Water Resources Commission Guidelines and Drawings or the Australian Standards. Approval to incorporate either sewerage reticulation or a common effluent disposal scheme in a development project is subject to a Council decision. Low pressure sewer systems may be used in development subject to the approval of the Director Civil Operations PRELIMINARY SEWER CONCEPT PLAN Prior to proceeding with detailed design the Consultant shall:- (a) (b) Obtain from Council "as constructed" sewer information relevant to the proposed development and the approved connection points for the development. Liaise with Council to ascertain whether a Preliminary Sewer Concept Plan is required. Where Council requires a concept plan, it shall be completed by the Consultant include the following information:- Location, size and alignment of gravity sewers Location, size and alignment of rising mains Location of pump stations and lift stations Contour information generally at 5m intervals Approved sewer connection points Contributing catchments (internal and external) showing the equivalent population (EP) The flow contributing to each section of main including the estimated design capacity. See example below:-

4 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B EP 965 Flow Pipe Size Max Pipe Cap 15.4 l/sec 225 diameter 25 l/sec Access for maintenance of the system should be considered when locating manholes, pump and lift stations, etc TRUNK MAINS Trunk mains are those major components of Council's Sewerage Scheme deemed necessary to provide services on a regional and district basis. Mains over 300mm diameter shall be free of sewer connections with a separate sewer main to be provided as the development service main PIPES AND CLASS The type and class of pipe shall comply with Council's Specification, refer 3.7. Reticulation sewers shall be of the following diameters: 150mm, 225mm and 300mm. Common effluent lines shall be of the following diameters: 100mm, 150mm and 225mm HOUSE CONNECTIONS SEWERAGE (a) General House connection shall be provided at the lowest point of each allotment and at sufficient depth to serve the entire allotment or in the case where building envelope restrictions apply, the depth of the connection shall allow the entire building envelope area to be served. The alignment of house connection branches shall be typically 1m from side boundaries. Council will not permit combined house drains House connection branches shall be connected into manholes wherever practical in preference to in line connections. It is a mandatory Council requirement that where house connection branches cross road carriageways they shall connect into manholes and be 150mm diameter minimum. (b) Size The minimum diameter of a single house connection branch shall be 100mm for Residential Precincts and 150mm diameter in Industrial and Commercial Precincts.

5 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B (c) Depth The upstream invert level of the 45 oblique junction at Council's reticulation sewer (control point) shall be low enough to control the whole of the allotment to be serviced or the area of the building envelope as applicable using the following criteria:- Minimum cover to top of house drain mm Minimum grade for 100 dia... 1 in 60 (1.66%) Minimum grade for 150 dia... 1 in 80 (1.25%) For calculation purposes, the house drain alignment shall generally be 1 metre from side and rear boundaries and 6 metres from the front boundary. (Where building envelope restrictions apply the house drain shall be assumed to follow the envelope boundaries). Some assessment should also be made of the likely cut to fill on the control block. Subject to the above criteria being met, the depth of any house connection at the inspection tee as defined on Standard Drawing shall be between: Minimum depth to invert after jump up mm Maximum depth to invert after jump up mm Allotments controlling the sewer design shall be clearly indicated on the design drawings. Where the depth of the sewer line exceeds 3m, house connections should preferably be connected to manholes. (d) Jump Ups Jump ups shall be constructed in accordance with Standard Drawing Where the depth of the Type C jump up exceeds 2500mm one of the following material shall be used in lieu of upvc: The slope junction and adjoining bend shall be ductile iron with fusion bonded epoxy coating Joint Committee approved glass reinforced plastic drop sewer junction CED (a) General House connections shall be provided at the lowest point of each allotment and at sufficient depth to serve the entire allotment. In the case where building envelope restrictions apply, the depth of the connection shall allow the entire building envelope area to be served. The alignment of house connection branches shall be typically 1m from side boundaries. Council will not permit combined house drains. House connection branches shall be connected into manholes wherever practical in preference to in line connections. It is a mandatory Council requirement that where house connection branches cross road carriageways they shall connect into manholes. Note: The outlets of septic tanks must be include either a Drenco or Zabel filter before the house connection. (b) Size

6 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B The minimum diameter of a single house connection branch shall be 100mm for residential precincts. In commercial or industrial precincts the connection branch size shall be determined in accordance with but shall not be less than 100mm diameter. (c) Depth The upstream invert level of the junction at Council's CED line shall be low enough to control the whole of the allotment or building envelope in the case where building envelope restrictions apply. Criteria governing the junction invert shall be:- Minimum cover to house drain mm Cover at septic outlets mm Desirable minimum grade for 100 dia... 1 in 60 (1.66%) (Absolute minimum grade... 1 in 100) Desirable minimum grade for 150 dia... 1 in 80 (1.25%) (Absolute minimum grade... 1 in 100) The fall of the house drain on the control block shall be calculated assuming the septic is located at the furthest point in the building envelope or allotment from the connection point. The house drain alignment for the calculation of fall shall generally be 1m from side or rear boundaries and 6 metres from the front boundary. In the case where building envelope restrictions apply, the house drain shall be assumed to follow the envelope boundaries. Some assessment should also be made of the likely cut to fill on the control block. (d) Jump Ups and Inspection Openings ALIGNMENT OF MAINS Jump ups and inspection openings shall be constructed generally in accordance with Standard Drawing Inspection openings shall be incorporated at all house connection junctions and changes in direction less than or equal to 45 degrees. Where the depth of the inspection shaft exceeds 2500mm, the junction and the adjoining bend shall be ductile iron with fusion bonded epoxy coating. The maximum depth to the invert of the house connection after the jump-up shall be 1000mm. The minimum depth to the invert of the house connection after the jump-up shall be 600mm. All junctions shall be encased in concrete grade N20 as shown on the Standard Drawing. Manholes shall be provided in CED schemes in accordance with the requirements of Preferably mains shall be located in the road reserve on a 1.5 metre alignment and on the opposite side of the road from water reticulation and other services. Any proposed alteration to the alignment in the road reserve must be approved by the Director and the relevant Public Utility Authority. Common trenching for water and sewerage together with any other utility is not permitted.

7 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B Where it is impractical to locate the main within the road reserve, the Director may approve an alternative alignment within private property. In such instances, consideration must be given to the accessibility of the main and manholes. Where the Director approves gravity mains or pressure mains within allotments the following offsets shall generally apply:- Front and rear boundaries meters Side boundaries metres Refer 2.11 for easement requirements. Where building envelope restrictions apply to a development, the Director may give approval for non standard sewer/ced alignments. In such instances the sewer/ced must be outside the building envelope. Unless approved by the Director, sewer/ced alignments should be located above the defined flood level. If a sewer/ced alignment is below flood level allotment filling may be required by Council in the vicinity of sewer/ced manholes or access chambers. Attention is drawn to the requirements of AS Clause DEPTH OF SEWERS/CED LINES Sewers/CED lines shall be designed at the shallowest possible depth such that:- (a) All allotments are served based on the house connection design criteria as per (b) Council's minimum cover to the top of a pipe is:- Allotments m to top of pipe Footpath...0.6m to top of pipe Roadways...0.9m to top of pipe (c) (d) There are no clashes with other services including stormwater and Public Utilities and a minimum vertical clearance between services crossing each other of 150mm clear. Where a main is located in a cut area or its cover reduced by the provision of a driveway to service an allotment then the minimum cover shall be maintained as per (b) above. The maximum cover to sewer/ced mains shall be in accordance with the manufacturers technical specifications and recommendations for the type and class of pipe used together with bedding trench conditions and soil type and shall not exceed 5.0m. Where design calculations allow the laying of sewers/ced mains at depths greater than 5.0m specific written approval from Council shall be obtained by the Consultant following discussions with Council DESIGN CRITERIA - SEWERAGE GENERAL Sewers shall be designed to accommodate flows from the Developments catchment as well as external catchments in accordance with Council's Strategic Plan consistent with long term development equivalent populations (EP). The proposed sewerage scheme shall be extended to the boundary of the development as nominated by Council.

8 Ref: 27REVB DOC Date: 31 Jan 2005 Issue: B PIPE VELOCITY Generally Council's minimum velocity for gravity sewers is 0.6 metres/second for Maximum Daily Flow. For 150mm sewers this requirement may be difficult to achieve while maintaining economical depths, therefore for 150mm sewers Council will permit the minimum grades as set out in Table 2.7A, subject to Sewers 225mm and greater shall be designed on gradients such that the velocity for Maximum Dry Weather Flow (C 2 x 225L/EP/day) exceeds 0.3m/s and the velocity for Maximum Daily Flow (C 1 x 225L/EP/day) should be at least 0.6m/s. The appropriate "C" factor can be obtained from Figure 2.7A, which is a copy of drawing number A of the Water Resources Commission Guidelines MINIMUM GRADES Minimum grades for sewer reticulation mains shall be as summarised in Table 2.7A. Table 2.7A Minimum Pipeline Grades DIAMETER 100mm 150mm 150mm 225mm 300mm - House Connection Branches - House Connection Branches - First MH length, head of sewer - Second MH length - Remaining MH lengths (see note below) MINIMUM GRADE 1 in % 1 in % 1 in % 1 in % 1 in % 1 in % 1 in % Note: In flat country or where difficult excavation conditions exist and specific written approval has been obtained by the Consultant following preliminary discussions with Council, a minimum grade of 1 in 200 for the remaining manhole lengths of 150mm control sewers can be adopted CAPACITY Gravity sewer shall be sized to flow no more than 3/4 full depth at the maximum possible flow based on the following criteria:- Manning "N" value is for all mains Design daily flow is 225 litres/person/day Equivalent population (EP). Refer Table 2.7B. The maximum possible flow should then be calculated by applying C 1 from Figure 2.7A to the design daily flow. The Calculation for maximum flow in litres/second is:- Number of EP x 225 litres / person / day / x C1 Factor 24 x 3600

9 Figure 2.7A

10 Table 2.7B Equivalent Population Densities Use Unit of Basis Sewerage Density (EP) Accommodation Units 1 bedroom bedroom bedroom 2.5 Camping Grounds Caravan Park Commercial Premises/Offices Detached House Display Home Educational Establishment - Kindergarten/Primary - Secondary/Tertiary Family Group Home Fast Food Outlet Garden Centre General Industry General Store Hospital Hotel with accomodation Hotel without accomodation Indoor Entertainment Other Institution Laundromat Light Industry Local Surgery Major/Noxious Industry Medical Centre Mobile Home Park Motel Multi-Unit Building (refer Accommodation Building) Nursery Nursing Home Place of Worship Professional Office (refer Commercial Premises) Reformative Institution Relocatable Home Park Restaurant Retirement Village Service Station Shop/General Store Showroom/Sales Area - Principle Use Enclosed - Principle Use Outdoors Student Accommodation Sporting Centres Theatres/Cinemas Site Caravan Site 100 sqm GFA House Home Student Student Bedroom 100 sqm GFA Employee 100 sqm GFA 100 sqm GFA Bed Accom. Room 100 sqm GFA 100 sqm GFA Bed Machine Gross Ha Patient Gross Ha 100 sqm GFA Site Accom. Room Sqm GFA Employee Bedroom Seats Bed Site 100 sqm GFA Unit Site 100 sqm GFA 100 sqm GFA 100 sqm Bed Court Seat

11 2.7.9 DESIGN CRITERIA COMMON EFFLUENT DISPOSAL GENERAL The CED scheme shall be designed to accommodate flows from the Development catchment as well as potential external catchments. Liaise with Council's Design and Development Section to ascertain the likelihood of external catchments PIPE VELOCITY Refer Water Resources Commission Sewerage Guidelines Section MINIMUM GRADES CAPACITY Refer Water Resources Commission Sewerage Guidelines Section CED lines shall be sized to flow no more than 3/4 full depth at the maximum possible flow based on the following criteria: Manning "N" value is for all mains Average Daily Flow is 140 litres/ep/day Equivalent populations (EP). Refer Table 2.7B. The maximum possible flow in litres/sec should be calculated by: Number of EP x 140l/person/day x 3 24 x MANHOLES AND MAINTENANCE SHAFTS GENERAL Manholes shall be designed in accordance with Standard Drawing SPECIFIC COUNCIL REQUIREMENTS (a) (b) (c) (d) (e) (f) (g) (h) Manholes shall not be constructed within road carriageways, central medians and roundabouts. Precast manholes shall not be located in areas subject to flooding or where bolt down lids are required. Precast manhole components are permitted, however, the use of precast bases shall be at the discretional approval of the Director Civil Operations. Precast concrete surrounds shall be proprietary products approved by Council. The joint between the converter slab and surround shall be sealed with a watertight compound. External drops are not permitted for use with precast manholes. All holes in precast manhole walls shall be drilled or cored. Step irons are not permitted. Bolt down covers are required where the converter slab is below flood level or subjected to intermittent inundation e.g. overland flow paths

12 Council may approve the use of maintenance shafts to replace certain manholes in a system. Approval is at the discretion of the Director Civil Operations. (i) (j) (k) Rectangular manholes shall only be used within footpath verges where there is insufficient space due to Public Utilities Manhole bedding shall include bypass drainage in accordance with Standard Drawing wherever it is practical to connect the diversion drain to a stormwater system. Circular manholes less than 1200 deep shall be provided with rectangular lids DROPS THROUGH MANHOLES The type and dimension of drops through manholes shall be as specified in Standard Drawing The "X" drops are not permitted where the grade of the incoming sewer exceeds 10%. Where more than one (1) type "X" drop enters a manhole a 1200 manhole shall be constructed SEWERAGE SCHEME LOCATIONS Manholes in sewerage schemes shall be provided at the following locations: At changes in grade Changes in pipe diameter Changes in alignment At intersections with other sewers (maximum change 90 degrees) At changes in pipe material Not more than 90 metres apart for sewers up to and including 300mm diameter At the ends of sewer lines except house connection branches less than 30 metres in length At intersections of house connection branches crossing carriageways and sewer lines (Refer 2.7.6) CED SCHEME LOCATIONS Manholes in CED schemes shall be provided at the following locations: At the ends of lines except house connection branches less than 30 metres in length Not more than 300m apart At intersections with other CED branch lines At changes in direction in excess of 60 degrees At changes in pipe diameter At changes in pipe material At change in pipe grade PUMP AND LIFT STATIONS GENERAL The developer is responsible for the supply and installation of all equipment and materials associated with pump and lift stations. This includes the concrete benching in wet well base, pumps, electrical cabinet and associated wiring, level control, telemetry, internal pipework and well washer. Council requires that for each station the location and access to the station be shown on the engineering drawings in accordance with Standard Drawing

13 Overflows where required, refer , shall be provided in accordance with Standard Drawing Where stations are not readily accessible from a public road, particular attention to the following criteria is required. (i) (ii) (iii) (iv) (v) Vehicle access and site manoeuvrability. For large stations attention should be given to the vehicle type accessing the site Access road cross section and drainage Width of land required for access road Dedication of land for pump and lift stations and access road to Council in fee simple Fencing (where required) and landscaping shall conform to the general amenity and aesthetics of the area Pump stations and lift stations shall be designed in accordance with the Standard Drawings as applicable including completion of the required details on the diagrammatic layout drawing. The details shown on Council's Standard Drawings are typical only and it is the Consultant's responsibility to provide engineering drawings for the specific pump station. An approved electromagnetic flow meter shall be provided for all pump stations with design flow rates in excess of 10l/s. The flow meter shall be located in a manhole clear of the valve chamber. An output shall link the flow meter to an approved chart recorder provided in the switchboard and the telemetry terminal strip. The noise emitted by infrastructure elements shall conform with the current Noise Protection provisions. The location of pump stations will be such that they do not create inconvenience to any adjacent residences. The Consultant shall complete and submit for approval all tabulations and level information required on Council's Standard Drawings PUMP DESIGN CRITERIA (a) General Pump stations and lift stations shall incorporate two pumps. Friction losses in the rising main shall be calculated using the Hazen Williams formula viz.: Head Loss (m) = x L x Q C x D 4.87 where D = diameter (m) L = length of rising main (m) C = 120 Q = duty flow (m³/s) Fitting losses in the pump station pipework shall be assumed to be 6 times the velocity head (based on fittings sizes) for submersible stations and 12 times the velocity head for conventional stations. (b) Sewerage Both pumps operating in parallel shall be capable of pumping a minimum of:

14 EP x 225 x 5 litres/sec 24 x 3600 This parameter will dictate the duty of the pump operating singularly. Pump Well Storage capacity m³ = 0.9 x pump rate (l/sec) 12 (start per hour) Pumps must be able to pass a sphere of 75mm. Minimum pump efficiency 35% unless otherwise approved by the Director. Pumps with lower rotational speeds are preferred. (c) CED Both pumps operating in parallel shall be capable of pumping a minimum of: Flow = EP x 140 x 3 litres/sec 24 x 3600 This parameter will dictate the duty of the pump operating singularly. Pump will storage capacity m³ = 0.9 x pump rate (l/sec) 12 (starts per hr) Pumps must be able to pass a sphere of 10mm Minimum pump efficiency 35 per cent unless otherwise approved by Council's Director Pumps with lower rotational speed are preferred (d) Combined Pumping Systems On occasions pumping systems may need to be designed for catchments comprising part sewerage and part CED. In these instances, both pumps operating in parallel shall be capable of pumping the combined flow rate calculated for each scheme viz.: Flow = EP(1) x 225 x 5 + EP(2) x 140 x 3 24 x x 3600 Pumps must be able to pass a sphere of 75mm Minimum pump efficiency 35% unless approved otherwise by Director - Design and Development PUMP WELL CRITERIA Pump wells shall meet the following criteria:- When determining the well diameter and opening size, particular attention should be paid to the type and volute size of the pumps chosen to ensure the pumps are free of obstruction for installation and removal Stations with incoming flows in excess of 30 l/sec shall have a dividing wall and inlet structure in accordance with Standard Drawing

15 The minimum storage depth allowable is 300mm Each station shall have only one inlet. A receiving manhole shall be provided where more than one sewer main is to discharge to the station Stations shall be fitted with an automated well washing facility approved by Council All internal surfaces shall be protected by a suitable non-corrosive liner and/or coating When determining the civil design of pump station structures over 4.0m deep calculations shall be provided to Council with regard to flotation where applicable. The design factor of safety against flotation shall be 1.5 (structure only) SPECIFIC COUNCIL REQUIREMENTS All works are to be carried out in accordance with Council's current specifications as described in 3.7 of this manual. At the completion of the design of the mechanical / electrical facilities the developer is required to submit the following for approval prior to commencement of any work on the station:- Pump curves and schedules of technical details for the selected pumps (3 off) as nominated in the specification. Duty points shall be clearly indicated on the pump curves. The design drawing of the control cabinet including schematic drawings detailing components to be installed as well as telemetry drawings and radio survey report where required (3 off). An Energex application for power, fully completed, for signing by Council as the owner of the station. A copy of Council's receipt for a 25mm water application. The developer shall complete the water application. The developer will be responsible for payment of all fees associated with the pump station fit out, including those for power and water connections PRESSURE MAINS (a) Capacity Pressure mains shall in general conform to the Water Resources Commission Guidelines Section 4.1. Mains shall be sized to take the design flow at an absolute minimum velocity of 0.6m/s and a maximum velocity of 1.6m/s. Pressure mains should be designed so that they remain full at all times ie pressure mains should not be designed to drain from a high point to the receiving manhole. Where a pressure main discharges to a manhole, the conditions in the length of sewer for 90 metres should be considered as septic and a non corrosive pipe installed for this length together with the provision of an inert lining to all internal surfaces of the pressure main discharge manhole. (b) Gas Release Valves for Pressure Mains Valves shall be of a size and type suitable for the particular application. All gas release valves shall be approved by Council and be of a design which guarantees that there is an air gap between the effluent and sealing system at the gas discharge point.

16 Valves shall be located as shown on the Engineering Drawings and in general shall be positioned at major and minor high points. The Consultant shall ensure the cover over pressure mains is increased in the area of the gas release valve such that the valve can be installed in accordance with Standard Drawing (c) Scour All sags in rising mains shall be provided with scour facility. The scour line may discharge to a sewer manhole (preferable arrangement) or to a pump out pit, in accordance with Council s Standard Drawing. No scour facility is required on CED rising mains of diameter less than 50mm. (d) Cover to Pressure Mains (i) New Pressure Mains The maximum and minimum cover to pressure mains shall be in accordance with Council's Standard Specification for Sewer Reticulation 3.7. Where the cover to pressure main does not comply with Council's Standard Specification then the written approval of Council shall be obtained prior to the lodgement of the engineering drawings. The drawings will detail the cover, pipe type and class as well as the construction requirements which are not as per Council's Standard Specification. (ii) Existing Pressure Mains Where a Development provides a roadway over the top of an existing pressure main then the section of existing pressure main under the road crossing shall be replaced with a section of ductile iron main road crossing lain in accordance with Council's Standard Specification for Sewer Reticulation. Where surface levels are increased or decreased over a section of existing pressure main then those sections of existing pressure main shall be relaid or replaced at Council's standard cover in accordance with Council's Standard Specification for Sewer Reticulation. (iii) Clearance Between Pressure Mains Horizontal The minimum horizontal clearance between pipe centerlines shall be the standard trench width for the specific size of main in accordance with Council's Standard Specification for Water Reticulation 3.6. Vertical The minimum vertical clearance between pressure mains shall be a clear 150mm PRIVATE PUMP STATION AND PRESSURE MAIN GENERAL Sewerage pumping stations serving more than one "Titled" property shall meet the requirements of Section of these Guidelines. Subject to Council approval, where a gravity sewer

17 connection is not available to a development, Council may approve a private sewerage pumping station which will discharge to the existing sewerage system via a rising main. It is the consultants responsibility to ensure that the Private Sewerage Pumping Station complies with the following requirements:- The Sewerage and Water Supply Act AS National Plumbing and Drainage Code. Section The current Environment Protection Regulation Generally in accordance with the Water Resources Commission Guidelines for Planning and Design of Sewerage Schemes Council's specific requirements as set out below: APPROVED CONNECTION POINT (a) General All costs associated with connection of a private pressure main to an existing sewer system (system analysis, design and upgrades to provide capacity) shall be met by the Developer. (b) Connection to Existing Gravity Main Council's preferred connection point is to an existing manhole. Council may require the provision of a non corrosive pipe installed for the length of sewer to the next downstream manhole and will require the provision of an inert lining to all internal surfaces of the pressure main discharge manhole. (c) Connection to Existing Pressure Main PRIVATE PUMPS Where the approved connection point location is to an existing pressure main, these works shall be provided by Council at full cost to the Developer. A private pressure main is not permitted to inject into another private pressure main. (a) Pump Flow Council required a minimum of two pumps that shall be sized after consideration of the following criteria:- Each pump has the ability to pump 5 times the design daily flow Flow Q = Number of EP x 225L/EP/day x 5(peaking factor) l/sec 24 x 3600 = Number of EP l/sec 62.84

18 (b) Pump Head The head required to be achieved by each pump at the above flow can be calculated as follows:- Head (metres) = h - y + fcp where h = Invert Level of connecting pipe at manhole or = head in rising main y = floor level of pump well fcp = friction losses in pressure main and pump station PUMP WELL CAPACITY AND OPERATION The capacity of the pump well for storage of sewage during pump malfunction should be as per Table 2.7C. Table 2.7C Pumpwell Storage During Breakdown CONTROL Inlet invert Alarm Level STORAGE DEPTH 300mm (min) Standby start 300mm (min) Duty Start Storage capacity m³ = 0.9 x Flow Q (l/sec) (min) 12 (starts per hour) Pump stop 150mm (min) Floor level Other than for storage capacity, the above depths are a general guide and Council may require the developer to provide details on detention times and proposed strategies to minimise the detention times. The pumps are to be set up to operate automatically as Duty/Standby and should be of the submersible electrical type. An alarm shall be provided in the form of a prominently positioned flashing red light set to activate at the invert level of the incoming house drain PRIVATE PRESSURE MAINS Private pressure mains shall generally conform with the requirements of Council's Standard Specification in Section 3.7and shall be sized in accordance with Section of these Guidelines SPECIFIC REQUIREMENTS As the private sewerage pumping station is a component of the internal plumbing and drainage, Council's Plumbing and Drainage Services Section shall check the design drawings for compliance with current Acts and relevant standards.

19 OVERFLOWS Owners of private pumping stations are responsible for all costs and charges associated with the installation, operation and maintenance. As constructed details detailing the location of the pressure main shall be submitted to Council. Overflows shall be designed and installed in accordance with Water Resources Commission Guidelines - Section 5.00 with reference to the Department of Environment and Heritage Draft Information Sheet - Pump Stations and Overflows. Refer also Standard Drawing CONNECTIONS TO EXISTING MAINS (WORKS BY COUNCIL) All connections to live sewer mains shall be made by Council at the Developers expense. Refer Appendix of the Guidelines EASEMENTS An easement in favour of Council shall be provided by the Developer as follows:- (a) (b) (c) (d) (e) Over all sewers (gravity or pressure) in industrial and commercial sites (Note additional accessible manholes may be required where there is total site coverage) Council maintained sewers (gravity or pressure) in group title developments Any gravity main located more than 1.5 metres off a residential property boundary or located in any position which could be legally built on within an allotment (this excludes sewers constructed outside building envelopes) All pressure mains located other than within the footpath verge The minimum acceptable easement width shall be 4.0 metres. The actual width of the easement shall be determined subject to the following:- Size of main Depth of main Location of main Soil conditions Topography Vehicle access requirements ENGINEERING DOCUMENTATION ENGINEERING DRAWINGS The information to be detailed on the sewerage reticulation drawings is set out in Section 2.1. The scales for Sewerage reticulation drawings shall be:- (a) Plans - generally at a scale of 1:500 or 1:1000 (b) Longitudinal Sections - at a scale of 1:1000 Horizontal and 1:100 Vertical Longitudinal Sections shall show the equivalent populations, flow and design capacity of all sections of mains.

20 SPECIFICATION The specification for CED and Sewerage Reticulation shall conform with the technical requirements of Council's Standard Specification in Section SUBMISSION OF ENGINEERING DRAWINGS / JOB SPECIFICATION An application checklist for sewer/ced design is included in Appendix B CONSTRUCTION PROCEDURES All construction procedures including testing and certification shall comply with Section "AS CONSTRUCTED" REQUIREMENTS All "as constructed shall comply with Section 4.1.