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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
BackgroundBackground
Consent Decree
Project DrivesProject Drives
Interceptor and Relief have never been inspected
Located nearLocated near environmentally sensitive areas
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BackgroundBackground
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
gg
PipelinePipeline
Condition AssessmentCondition Assessment
Verification of as-built
SurveySurvey
information
Manhole locations and elevations
Large trees/canopy
Wetland/stream location
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Condition AssessmentCondition Assessment
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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Condition AssessmentCondition Assessment
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
Condition AssessmentCondition Assessment
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
Rehabilitation OptionsRehabilitation Options
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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Rehabilitation OptionsRehabilitation Options
Deteriorating System
Rehabilitation ConsiderationsRehabilitation Considerations
Site AccessLimited Hydraulic CapacityJoint AlignmentFlow DiversionLife Cycle CostLife Cycle CostEnvironmental Concerns
Active Infiltration of Existing System
Patapsco Interceptors
Rehabilitation OptionsRehabilitation Options
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
Rehabilitation OptionsRehabilitation Options
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
Rehabilitation OptionsRehabilitation Options
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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Rehabilitation OptionsRehabilitation Options
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
Rehabilitation OptionsRehabilitation Options
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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Rehabilitation OptionsRehabilitation Options
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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Design ConsiderationsDesign Considerations
Patapsco Valley State Park (DNR)
Temporary RightTemporary Right--ofof--EntryEntry
(DNR)Amtrak/ CSX Transportation, IncMaryland State Highway AdministrationBaltimore Gas & Electric CompanyDiageoMaryland Environmental Service
Design ConsiderationsDesign Considerations
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
Design ConsiderationsDesign ConsiderationsThe DesignThe Design
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Design ConsiderationsDesign ConsiderationsThe DesignThe Design
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 @Celina_perez@urscorp.com
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