Dominion Road Sewage Pumping Station and Force Main Replacement. Doug Pease, P. Eng. April 8, 2013 WEAO

Transcription

1 Dominion Road Sewage Pumping Station and Force Main Replacement Doug Pease, P. Eng. April 8, 2013 WEAO

2 Overview Background existing PS and force main Condition assessment Design of new station Design of new force main Constructability issues

3 Existing Station Located in Town of Fort Erie Constructed in 1972 Major upgrade in 1995 Source: Google Maps

4 Existing Station Residential, Industrial and Commercial ~5,100 people Receives flows from: local sanitary system two tributary pumping stations Peak Dry Weather Flow: 33 L/s Rated Capacity: 225 L/s Largest rated capacity of any pumping station in Fort Erie Dominion Road PS Source: Google Maps

5 Existing Station Dry / Wet Well design Two 250 HP raw sewage pumps - One duty, one standby Electrical / Control / Generator room Wet Well ladder access

6 Existing Force Main 4,500m force main Discharge to Anger Avenue WWTP collection system 400mm HDPE pipe, three pressure classes Series 60 Series 80 Series 100 Poor access PS Source: Niagara Navigator

7 Existing Force Main

8 Condition Assessment Planned upgrade Process pumps and piping Generator Electrical systems Controls R.V. Anderson Associates Limited retained to complete upgrade design First step - condition assessment of existing station: Confirm scope of upgrade Identify specific maintenance and operational concerns with existing equipment

9 Dry Well Limited working space Small footprint Horizontally mounted pumps Influent sewer configuration Flooding risk

10 Dry Well Difficult pump removal Poor personnel access

11 Hazardous Areas - OESC Ontario Electrical Safety Code Section 22 - specific rules for sewage pumping stations Dry well spaces now defined as Class I, Zone 2 hazardous areas Existing configuration no physical separation between dry well and electrical/control room Electrical/Control Room Dry Well Electrical/Control room must be treated as Class I, Zone 2

12 Hazardous Areas - OESC Options: Install new electrical equipment suitable for Class I, Zone 2 Declassify electrical room using continuous positive pressure ventilation Equipment failure room reverts to Class I, Zone 2, de-energize equipment Construct a new electrical/control building. Existing electrical room becomes dedicated pump removal room

13 Other Generator Structural Water cooled not environmentally friendly or economical Poor access for operations and maintenance Aging superstructure in poor condition

14 Preferred Solution Condition assessment identified areas of concern that would greatly increase scope of upgrade Compliance with OESC $$$ Upgrade cannot easily resolve dry well concerns Upon review, Niagara Region determined it would be most cost effective to construct a new facility.

15 New Station Design Criteria Existing FM Modest capacity increase to accommodate built out PDWF: 225 L/s 260 L/s Dry / Wet Well design Construct on same property as existing PS Maintain existing PS in operation during construction Connect to existing force main Existing PS Meet current standards Niagara Region design guidelines, OESC, etc Source: Niagara Navigator

16 Design 11m deep, 144m 2 substructure 5m high, 185m 2 control building

17 Process Design Flow Meter Chamber Two wet wells 3 dry pit submersible pumps 2 duty, 1 standby VFD control flow matching Capable of drawing from each well with 2 pumps Flow meter located in chamber WW 1 WW 2 Pump Room

18 Process Design Electrical/Control Room: Unclassified Pump Room: Class I, Zone 2

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20 Wet Well

21 Pump Room

22 Pumping Station Design 600 kw diesel generator Mechanical room for ventilation equipment Washroom with janitor s space Wet well - Top slab at grade - Stair access

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24 Generator Room

25 Force Main Design Original plan connect new PS to existing force main Transient analysis to determine the effects of increased flow from new station A transient (or surge) condition occurs when there is rapid change in flow velocity in a pipe resulting in pressure variations in both time and location throughout the system Can occur during sudden pump start/stops from power loss or normal operation Modeling Software Pipe2010

26 Force Main Design Negative pressures during transient condition exceed force main collapse pressure rating over much of length HGL Pressure Envelope Elevation (m) Force Main PS Force Main Length (m)

27 Force Main Design Decided to replace ~ 50% of force main New alignment Municipal ROW 300m longer Total replacement 3550m Increased pipe diameter (400mm to 450mm) lower system pressure at duty flow rate by 45% 4 new air/vacuum relief chambers Existing New PS Source: Niagara Navigator

28 Constructability Considerations Shallow bedrock Minimize building footprint Force main profile Groundwater Permit to Take Water Dewatering requirements clearly stated in Contract Documents Existing Force Main Special valve chamber at connection to existing FM New

29 Project Update and Special Thanks Awarded May 2012 Force main construction summer/fall 2012 Station excavation began September 2012 Concrete for substructure began January 2013 ongoing Special Thanks! Co-authors: Ryan Boone, EIT - R.V. Anderson Associates Limited Graeme Guthrie, CET Niagara Region Niagara Region Water and Wastewater group

30 QUESTIONS? Doug Pease, P. Eng x 22 dpease@rvanderson.com