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    Portsmouth Sewershed Inflow and Infiltration Reduction Project

    Project Background

    During the 2010 Sewage Infrastructure Master Plan, it was noted that the sewage collection area that flows to the Portsmouth Pumping Station located in Aberdeen Park, was subject to abnormally high levels of inflow and infiltration from groundwater and other otherwise clean water sources.  These excessive ‘extraneous flows’ result in additional flow in the sanitary sewer that must be collected, conveyed, pump and treated.  It also contributes to other problems including surcharging sewers, basement sewage backups and increased bypassing of sewage to the environment during heavy rainfalls or rapid snowmelts.

    For additional information on sewage backups, please see the following Utilities Kingston webpage:  http://www.utilitieskingston.com/Wastewater/BasementFlooding/Awareness

    Similar to the work completed in the area tributary to the North End Trunk Sewer in 2008 through to 2011, this project involves identifying the sources of inflow and infiltration, prioritizing, and completing the necessary repairs to the sewer to reduce the amount and severity of the leaks.  This project is complex and utilizes many different technologies to identify, prioritize and rectify the deficiencies. It involves primarily ‘trenchless methods’ which access the sewer lines via the maintenance holes and does not require digging.  It also involves efforts on public and private property. 

    The technologies are described in further detail below.

    A project team consisting of D.M. Robichaud Associates (‘No-Dig’) and Civica Infrastructure was retained by Utilities Kingston in September 2014 to complete this multi-phased project.

    Planning

    Phase 1 - Investigations and Data Collection

    The first step in addressing the problem of excessive inflow and infiltration is to inspect the sewers and understand the nature of the problem. There are many sources of extraneous flow and these include the following:

    Public Side (our stuff)

    Private Side (your stuff)

    Both sides

    Cracks, breaks and unsealed joints in the sewer that groundwater can leak into.

    Sump pumps pumping area groundwater into the sewer (illegal connection)

    Cross-connections (storm connections that were accidentally, or intentionally, connected into the sanitary sewer)

    Poor connection between the services and the sewer main, another location where groundwater can seep in.

    Rooftop downspouts flowing directly into the sewer lateral.

    Leaky sewer laterals/services.  The lateral is shared, so the problem can be on the private side, public side or both.

    Nearby watermain leaks (that make their way into the sewer)

    Reverse slope driveways collected by a pipe that flows into the sanitary sewer rather than the storm sewer.

     

    Surface inflow through manhole lid holes and cracks in the pavement.

     

     

     

    There are various tests to identify these types of deficiencies and they include the following:

    • CCTV Inspection of the sewer mains and sewer laterals. Through the maintenance holes, a camera is inserted that drives along inside the sewer. It stops, pans, tilts and refocuses to identify and catalogue deficiencies it finds. This activity is preceded by sewer flushing (to clean the sewers and free them of debris) and sometimes additional cutting or reaming, to remove obstructions like calcite, root masses and/or protruding laterals. Three-day advanced notification is provided for sewer flushing.
    • Fog and dye testing.       These are two techniques that allow identification of cross-connections with storm water sources and to confirm connectivity. For fog testing, a non-toxic, non-staining fog is forced into the sewer and conclusions are drawn from where the fog emerges.       If a home is properly plumbed without illegal connections, the only place fog will be seen is emitting from the sewer stack. If illegal connections are present, this may result in fog emitting from the downspout, for example. Advanced notices are provided for fog-testing and emergency services are notified.
    • Sewer joint pressure testing.       A robotic device can be introduced into the sewer. This device stops at joints in the pipe and exerts pressure. If the pressure dissipates, it is concluded that the joint can leak. Joints that fail the pressure tests are then placed on a joint packing/sealing program.
    • Maintenance hole inspections. This involves either inspection from the surface or by confined-space entry to identify and document leaks in the maintenance hole walls or chimney.
    • Property inspections.       Staff will observe drainage issues by inspecting properties. In particular, staff look for downspouts (to make sure they discharge to your lawn), reverse slope driveways (to determine where a dye test might be necessary to confirm connectivity) and other things like rear-yard catch-basins and other unique drainage challenges.
    • Sewage flow monitoring.       Flow monitoring is completed within the sewer at strategic locations as well as continual flow monitoring at the Portsmouth Pumping Station. This information can be used for benchmarking, goal setting and progress tracking.
    • Electroscan Sewer Testing.  Electroscan is a relatively new technology available to D.M. Robichaud that runs a sensor through the sewer with a flusher at the same time, and calculates the leak potential.  More information on the process can be found here.

    The majority of Phase 1 of this project was completed in 2015. 

    Phase 1b – Planning

    This phase is the part of the project where collected data is reviewed, a plan is developed, targets set and priorities established.  This phase plans for various work types to be completed during construction in a prioritized manner to seek and eliminate the leaks with the best cost:benefit ratio. For example, if a particular pipe is found to have very minor leaks at all joints, but one or two significant cracks that account for 90% or more of the leakage, there is justification to conduct only the work necessary to eliminate the large leaks, at least initially. 

    Phase 1b of this project was completed in winter & spring of 2016, which culminated in a thorough report documenting the primary sources of extraneous flow, on the public side of the system.  This report has provided recommendations for moving forward that were authorized in the summer of 2016.

    Design and Construction

    Phase 2 – Construction

    Overview:  

    The majority of construction work that is part of this project will be of minimal impact by using ‘trenchless technologies’.  Trenchless technologies do not require open cut work, but is work that is executed using the existing maintenance holes as access points only.  Trenchless technologies may not be feasible in all locations and thus some localized digs might be required. 

    Trenchless technologies are not free of all disruptions, but the duration and nature of the disruption to area residents is significantly reduced. 

    The following table describes some technologies that are likely to be utilized as part of Phase 2 of this project:

    Technology

    Description

    Joint Sealing and service connection sealing. (trenchless)

    When pressure tests have identified that a joint or service connection has failed the test, the feature can be sealed by grout injection completed under pressure.  The feature is then retested to ensure the grout has created a successful seal.

    Spot repairs (trenchless)

    If there are leaky cracks or joint/connection configurations that cannot be sealed with grout, a short section of cured-in-place pipe liner can be installed over the defect and cured in place to form a tight seal against the sewer wall preventing further leakage.  This are cured with either steam or UV.

    “T-Liners” (trenchless)

    This is similar to the above except it forms a cured-in-place repair to the connection point of a sewer lateral to the sewer main.  It is T-shaped with the end of the T pointing up the lateral.  It is then cured-in-place using steam or UV to form a water tight seal.

    Grouting (trenchless)

    Aside from sealing joints and service connections, grouting may be used in other situations with active water leakage including cracks with voids and other structural deficiencies in the pipe or maintenance holes.

    Full length sewer lining (trenchless)

    If a sewer main is found to be leaky along its entire length and/or with minor structural defects, it may be more cost-effective to install a liner inside the sewer for the full length.  This is called ‘Cured-In-Place Pipe’ or CIPP.  Essentially, the process creates a new seamless pipe inside the old host pipe.

    Lateral lining (trenchless)

    Similar to sewer lining, this is the process of lining the sewer lateral.  If sewer laterals are found to be leaky, it may be cost effective to line the lateral.  This can be done from the main to the property line (with a new cleanout installed at the property line) or all the way to the home (with cost sharing with the home owner).

    Maintenance hole spray-on lining (trenchless)

    If maintenance holes are leaky, it may be cost effective to line the inside using a spray on lining technique which effectively seals the maintenance hole from infiltration.

    Dig and Fix

    If sewer defects are identified that simply cannot be rectified using trenchless techniques, traditional dig and fix repairs will be used.

    Phase 2 of this project is planned for 2016 through 2018. This will be a multi-phased approach that will take successive efforts to reduce I&I in the study area.  

    Phase 2A started in the fall of 2016. and is continuing through the summer of 2017.  Please see the map below for the location of works that are part of Phase 2A.  This is the first round of rehabilitation attempting to reduce extraneous flows by 25% for the 1-in-25 year storm event.

    View a full sized map in a new window

    Schedule and Project Downloads

    The approximate schedule for this project is as follows.  Follow the links in the download column to view associated public notifications.

    Approximate Project Schedule

    Phase

    Activity

    Date

    Download

    Environmental Assessment

    The works to be completed as part of this project are considered maintenance activities and therefore constitute a Schedule A project which is pre-approved and does not require public consultation.

    Phase 1 – Investigations

    Sewer cleaning, inspection and preparation + maintenance hole and property inspections.  Sewer lateral inspections.

    Commenced April 2015

    (ongoing through 2015)

    Project Commencement Notice (1)

    Notice of sewer flushing (2)

    Fog and Dye Testing

    Commenced May 2015

    (ongoing through summer)

    Fog/Dye Testing door hanger (3)

    Sewer preparations (reaming root masses, deposits & protruding connections)

     July to December 2015

    None 

    Electroscan Sewer Testing October to November 2015 Electroscan Notice (4)

    Phase 1b – Planning

    Review, processing and interpretation of investigation data.  Reporting, including target setting and prioritized work plan.

    Winter 2015/2016

     None

    Phase 2A - Construction First Phase

    Phase 2A has been defined to target reduction of extraneous flows by 25%.  This work includes the following main activities (quantities are approximate):

    • ~10-15 spot repairs by excavation.   These are locations that cannot be repaired by trenchless means and need to be excavated and repaired manually.
    • ~25 trenchless spot repairs.  These are locations of cracks or defects that can have a liner applied via trenchless technologies to fix the defect.
    • ~75 sewer lines for grouting.  These are full length sewer segments with good condition pipe material, but need to have joints, connections and other defects sealed with grout to prevent infiltration.
    • ~45 manholes for spray lining.  These are leaky manholes that will be spray lined for water tightness.
    • ~30 sewer lines for lining.  These are sewer lines that are exhibiting sufficient defects that grouting isn't enough.  A full length liner is installed by Cured-In-Place-Pipe technology.
    • Targeted private side efforts.  These include targeted approach of homes with identified illegal sewer connections (not mapped).
    • Additional flow monitoring, rainfall monitoring, trench water level monitoring, and hydraulic modelling to allow for progress tracking.  

    If your home or sewer service will be directly affected by any of this work, you will receive a notice hand-delivered by the contractor.  Working is commencing in late August 2016 and is intended to proceed until year end.

    Update (September 5, 2017):  Sewer lateral lining will start early September and proceed through early October.  This work will be done using a product called a "T-Liner", which extends from the sewer main in the street to the property line. If your service will be impacted by this work, you will receive notices (see on the right, items 7a, b...). 

    Update (November 7, 2017):  Based on findings from the Investigations Phase, a number of illegal private-side connections were identified.  Utilities Kingston will be pursuing disconnection of these connections by directly approaching property owners.  If your property was identified with illegal connection(s), you will receive a letter from Utilities Kingston describing the issue and letting you know whether or not you are eligible for funding via the Preventative Plumbing Program (see Notice 8 on the right).  

    Fall 2016

     

    Phase 2a APPROXIMATE SCHEDULE

    Phase 2a WORKPLAN MAP

    Phase 2a FLUSHING NOTICE (5)

    Phase 2a SEWER LINING - SERVICE INTERRUPTION NOTICE (6)

    Phase 2a T-Liner 48hr Notice (7a)

    Phase 2a T-Liner Dig Notice (7b)

    Phase 2a T-Liner Styrene Odour Notice (7c)

    Phase 2a T-Liner Work Finished Notice (7d) 

    Phase 2a Private-Side Illegal Connection Notice (8)

    Phase 2B - Construction Second Phase TBD.  Based on the degree of success of Phase 2A, a second, and possibly third phase of works will be designed and implemented. 2017-2018

     

    Contacts

    For further information on the Portsmouth Sewershed Inflow and Infiltration Reduction Project, please contact Utilities Kingston and/or its contractor (D.M. Robichaud Associates Ltd) and consultant (Civica Infrastructure) at the following addresses:

    Utilities Kingston
    Mike Fischer, P.Eng.
    Utilities Engineer
    85 Lappan's Lane
    Kingston, ON K7L 4X7
    Office: 613-546-1181, extension 2356
    Email: mfischer@utilitieskingston.com
    Utilities Kingston
    Trevor Howden
    Engineering Technologist
    85 Lappan's Lane
    Kingston, ON K7L 4X7
    Cell: 613-888-4566
    Office: 613-546-1181, extension 2338
    Email: thowden@utilitieskingston.com
    D.M. Robichaud Associates Ltd.
    Randy Kowal
    VP, Engineering Technologist
    627 Wentworth St. East
    Oshawa, ON L1H 3V8
    Cell: 905-767-0029
    Office: 905-433-1261
    Email: randy@dmrobichaud.com
    Civica Infrastructure Inc.
    Seth Monczka, BSc. Eng., EIT
    Project Manager
    330 Rodinea Road, Unit 3
    Vaughan, ON L6A 4P5
    Cell: 416-841-2076
    Office: 905-417-9792
    Email: smonczka@civi.ca