protect the environment: trenchless technology for the ... · 1 protect the environment: trenchless...

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Protect the Environment: Trenchless Technology Protect the Environment: Trenchless Technology for the Rehabilitation of Large Diameter Sewersfor the Rehabilitation of Large Diameter Sewers

Celina PerezCelina PerezSeptember 14, 2009

AgendaAgenda

BackgroundCondition Assessment Rehabilitation OptionsDesign ConsiderationsLessons LearnedQuestions

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BackgroundBackground

Approximately 29 square miles in Baltimore,

Patapsco SewershedPatapsco Sewershed

pp y q ,Howard and Anne Arundel Counties

Estimated population of 115,000

More than 256 miles of sewerMore than 256 miles of sewer


Consent Decree

Project DrivesProject Drives

Interceptor and Relief have never been inspected

Located nearLocated near environmentally sensitive areas

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Patapsco Interceptor

Project LocationProject Location

Patapsco Interceptor– Concrete tiles, 1950s – 100 LF of 21-inch– 7,250 LF of 42-inch– 7,850 LF of 48-inch– 4,070 LF of 54-inch– 42 MH Structures

Patapsco ReliefPatapsco Relief– RCP, 1980s– 4,580 LF of 48-inch– 14,740 LF of 66-inch– 240 LF of 72-inch– 32 MH Structures

Condition AssessmentCondition Assessment

Phase I – Preliminary EvaluationPreliminary Mapping

Project ScopeProject Scope

– Preliminary Mapping– System Condition– Site Conditions

Phase II – Data Analysis– Supplemental Survey– Evaluation of System– Analysis of Field Findingsy g– Rehabilitation Alternatives

Phase III - Design – Develop Construction Documents– Preparation of Required Permits

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Condition AssessmentCondition AssessmentProject PlanProject Plan

••CCTVCCTV

••PACPPACP

••Manhole Manhole InspectionsInspections

Tools usedTools used

Priority Priority RatingsRatings

ManholeManhole

DesignInspectionsInspections

••Site SpecificSite Specific

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PipelinePipeline


Verification of as-built

SurveySurvey

information

Manhole locations and elevations

Large trees/canopy

Wetland/stream location

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Structural

Manhole Inspection FindingsManhole Inspection Findings

– Deterioration– Wall Cracks– Frame and Covers

Inflow/Infiltration– Active Inflow/Infiltration

Evidence– Rain/River Induced I/IRain/River Induced I/I– Inflow Point Sources

Rim Elevation– Below Desired Grade

Active Infiltration and Loose Frame. Interceptor Manhole 6343

Structural– Pipe Deterioration

Condition AssessmentCondition AssessmentCCTV Inspection FindingsCCTV Inspection Findings

Pipe Deterioration– Missing Concrete Tiles– Longitudinal Cracks At 12, 3 and 9

o’clockInfiltration– Active infiltration/Infiltration

Evidence– Constant High Water Table due to

proximity to River

High Depth of Flow Interceptor Manhole 6333

proximity to RiverConstruction Related– Negative Slopes Observed– Settling of Pipelines– Poor soils

Missing Concrete Tile Interceptor Section 6318 – 6319

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Site conditions

Environmental Site AssessmentEnvironmental Site Assessment

Access to the system through existing and proposed temporary access paths

Need to minimize disturbance to waterways, forest stands, and the wildlife habitat

Maintain a canopy closure to prevent excessive rain impact and to minimize disturbance to Forest Interior Dwelling Bird (FIDS) habitat


Need to minimize disturbance to

Wetland DelineationWetland Delineation

disturbance to wetlands

Eight (8) defined wetland areas may be impacted by project

T i i iTo minimize impact, the route of the temporary access path was designed to minimize impacts on wetlands

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Condition AssessmentCondition AssessmentPriority RatingsPriority Ratings

Condition AssessmentCondition AssessmentPriority RatingsPriority Ratings

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Rehabilitation OptionsRehabilitation Options

Rehabilitate the Patapsco Interceptor to reclaim

CriteriaCriteria

Rehabilitate the Patapsco Interceptor to reclaim 14,300 LF of abandoned pipelineExtend the useful life of the Patapsco Interceptor and Relief Conveyance SystemReduce the amount of extraneous flows entering the system and thereby preventing system overflowsEconomies of scale


Sewer Rehabilitation

Rehabilitation EvaluationRehabilitation Evaluation

– Evaluation Considerations– Rehabilitation Alternatives– Unsuitable Alternatives– Suitable Alternatives

Manhole Rehabilitation– Structural– Elimination of I/I– Preventive Maintenance– Exterior Flow Protection

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Deteriorating System

Rehabilitation ConsiderationsRehabilitation Considerations

Site AccessLimited Hydraulic CapacityJoint AlignmentFlow DiversionLife Cycle CostLife Cycle CostEnvironmental Concerns

Active Infiltration of Existing System

Patapsco Interceptors


Chemical Grouting

Available Sewer Rehabilitation TechnologiesAvailable Sewer Rehabilitation Technologies

Specialty CoatingsPipe BurstingFold and FormCured-in-Place Pipe LiningSlip LiningOpen Cut ReplacementSpiral Wound PVC

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Rehabilitation OptionsRehabilitation OptionsUnsuitable Rehabilitation AlternativesUnsuitable Rehabilitation Alternatives

REHABILITATION ALTERNATIVE

COMMENTSALTERNATIVE

Chemical Grouting Best utilized for eliminating infiltration at pipe joints. Does not improve structural integrity of the pipe. Provides only a short-term solution.

Specialty Grouting/Coatings

Appropriate as a protective measure for preventing hydrogen sulfide corrosion. Does not improve structural integrity of the pipe.

Pipe Bursting Best utilized to upsize pipe diameters, typically for smaller diameter pipe sizes up to 18-inch. Also, not conducive for pipes in concrete encasements.

Fold and Formed/Deformed Lining

Best utilities for pipes up to 12-inches in diameter


ADVANTAGES

CuredCured--inin--Place Pipe (CIPP)Place Pipe (CIPP)

ADVANTAGESNo excavationsVarious shaped pipesLaterals reinstated internally and remotelyJointless solution

DISADVANTAGESFlow diversionProtruding laterals must be removed prior to installationCleaning importantInstallation and cure times

Designed for loads that the host pipe cannot supportHydraulic capacity maintainedSteam-curing can allow for shorter installation times

may exceed 24 hours per reachTypically more expensive than other trenchless rehabilitation technologies

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Rehabilitation OptionsRehabilitation OptionsSlip LiningSlip Lining

ADVANTAGESMinimal excavationDesigned for loads that the host pipe cannot supportRelatively quick and easy installation

DISADVANTAGESExcavation of insertion pits neededMost suitable for circular pipesMay require several jointsinstallation

Extremely competitiveBy-pass pumping is not typically required

May require several jointsAnnular space between liner and host pipeReduction in hydraulic capcity and flow area

Rehabilitation OptionsRehabilitation OptionsOpen Cut ReplacementOpen Cut Replacement

DISADVANTAGESADVANTAGESPotential disruption and damage to public and private propertiesSignificant restoration costsImpact other existing utilitiesNeed to assess geotechnical conditions

Corrects pipe sags and misalignmentsImprove hydraulicsElimination of direct sources of inflowRemoval of I/I sourcesNew service life for system

Shoring requirements and impacts of shoringNuisance noise and dustBypass pumpingPermitting requirements

New service life for system componentsIncrease pipe capacitySelect most appropriate pipe material

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Rehabilitation OptionsRehabilitation OptionsSpiral Wound PVCSpiral Wound PVC

DISADVANTAGESADVANTAGES

Bypass pumpingInsertion pits required every 800 feetLaterals reinstated internally and remotelyCleaning important

Various shaped pipesRelatively rapid installation period compared to open cut replacementHydraulic capacity maintained

Diameter reductionRequires man-entry of pipes


Available Manhole Rehabilitation TechnologiesAvailable Manhole Rehabilitation Technologies

Structural Rehabilitation– Grouting and Lining– Raising cones/stacks

Elimination of Infiltration– Grouting and Coating

Exterior Flow Protection

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Available Manhole Rehabilitation TechnologiesAvailable Manhole Rehabilitation Technologies

Preventative Maintenance– Clean interior surfaces– Adjust/replace frame and cover– Install internal chimney seal– Remove Steps– Rebuild bench/channel area– Inject chemical groutInject chemical grout– Install liner or coatings– Coat exterior surface of

exposed cones above grade


Patapsco Interceptor and Relief Rehabilitation OptionsComparison

AlternativesAlternatives

Point Repair, LF Replacement, LF CIP/Heavy Clean,

LFHeavy Clean,

LF Point Repair, LF Replacement, LF CIP/Heavy Clean, LF Heavy Clean, LF

8 6,800 5,300 2,500 0 0 0 0

8 6 800 300 2 00 5 000 3 800 912 2 500

Alternative 2: Provide Rehabilitation/Replacement of

Baltimore County, MarylandInterceptor Relief

Alternative

Alternative 1: Provide Rehabilitation/Replacement of Priority Pipeline Segments on the Patapsco Interceptor

8 6,800 5,300 2,500 5,000 3,800 912 2,500

0 0 19,000 0 0 0 0 0

0 0 19,000 0 0 0 19,000 0

Rehabilitation/Replacement of Priority Pipeline Segments on the Patapsco Interceptor and Relief

Alternative 3: Provide Rehabilitation by Cure-in-Place Pipe on the Patapsco Interceptor

Alternative 4: Provide Rehabilitation by Cure-in-Place Pipe on the Patapsco Interceptor and Relief

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Reclaim Interceptor

Solution: Alternative 4Solution: Alternative 4

Reclaim InterceptorExtend Useful Life of SystemReduce Extraneous Flows by Approximately 26 MG during a 2yr-24hr Rain Event Reduce or Eliminate Pump Station Wet Weather Related ProblemsRelated ProblemsReduce or Eliminate OverflowsEconomies of Scale

Design ConsiderationsDesign Considerations

MDE (Joint Application)

Permitting with Environmental AgenciesPermitting with Environmental Agencies

MDE (Water Appropriation)US Army Corps. of Engineer Department of Natural ResourcesPatapsco Valley State Park (DNR)MD Critical Area Commission (DNR)Wildlife and Heritage (DNR)Wildlife and Heritage (DNR)Maryland Historical TrustBig Tree ProgramDEPRM

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Patapsco Valley State Park (DNR)

Temporary RightTemporary Right--ofof--EntryEntry

(DNR)Amtrak/ CSX Transportation, IncMaryland State Highway AdministrationBaltimore Gas & Electric CompanyDiageoMaryland Environmental Service


Multiple Agency Coordination

ConstructabilityConstructability

Multiple Agency CoordinationAccess Roads– Existing– Improved– Temporary

Contractors’ AssessmentContractors AssessmentConstruction Timeline (CD Deadline)

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Design ConsiderationsDesign ConsiderationsThe DesignThe Design


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Lessons LearnedLessons Learned

Initiate Contact with Local Permitting Agencies asInitiate Contact with Local Permitting Agencies as early as possibleContinue communication with all agencies as the project evolvesSeek input from Multiple ContractorsFocus on minimizing environmental impacts andFocus on minimizing environmental impacts and keep an open mind for creative solutions

ConclusionConclusion

Project is currently under constructionProject is currently under construction

Currently one of the largest rehabilitation project in the country

C f l l i d di ti ith ll i l dCareful planning and coordination with all involved allows for the project to be successful

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Questions?

C li @[email protected]