Las Pulgas Landfill Phase I Clean ClosureMarine Corps Base Camp Pendleton, Ca

SWANA Western Regional Conference

April 2013

Presented by Marielle Coquia, P.E.

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Agenda

• Project Overview – Las Pulgas Landfill Background

• Clean-Up and Abatement Orders

• Corrective Action Plan

• Corrective Action Work Plan – Clean Closure

• Clean Closure Construction

• Phase I Reconstruction

Project Overview – Las Pulgas Landfill Background

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Project Overview- Las Pulgas Landfill Background

• 1971 - Disposal operations began with acceptance of municipal solid waste generated from only base operations and residences.

• The landfill is a Class III WMU operated by civilian Federal employees, using a typical progressive slope or ramp method of waste placement.

• 1998 – the landfill expansion increased the footprint from 39.5 acres to approximately 89 acres.

• 1999 – Phase I was constructed with a GCL and LCRS system over approximately 8 acres

• 2003 - Two small tears were observed in the exposed side slope liner of the Phase I cell and placement of waste was voluntarily stopped. Approximately 250,000 cy was in place.

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Clean-Up and Abatement Orders

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Clean-Up and Abatement Orders

• 2006 – San Diego RWQCB issued a Clean-Up and Abatement Order (CAO)– to address violations with

WDRs– remediate the deficiencies

cessation of Phase I operations

• 2007 – San Diego RWQCB issued Addendum No. (CAO)– corrective construction to

achieve compliance with WDRs and CCR Title 27 or

– Clean closure pursuant to CCR Title 27 Section 21090 (f)

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Clean-up and Abatement OrderKey Points• Identify and Repair all Defects in Existing Foundation/Subgrade, Composite

Liner and Operations Layer. A comprehensive field investigation will be conducted to identify, and repair or replace, all defective portions of the waste liner structure/liner system, and foundation/subgrade for the Phase 1 WMU that fail to comply with the performance requirements of CCR Title 27 section 20240(d), requirements of Order No. 2000-54, and the original design construction specifications (EMCON, 1997) for the Phase 1 WMU.

• Removal and Management of Wastes. Wastes (including contaminated soils) will be removed from all defective areas of the Phase 1 WMU. Waste removal and management will be in accordance with all applicable Federal, State and local requirements.

• Liner System and Foundation/Subgrade Removal and Repair. All defective portions of the composite liner system (including basal and side slope liners) and foundation/subgrade of the Phase 1 WMU will be repaired and/or replaced to comply with WDR Order No. 2000-54.

• Clean closure pursuant to CCR Title 27 Section 21090 (f)

Corrective Action Plan

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Corrective Action Plan – Proposed Two Alternatives

• Phase I Corrective Action Plan was prepared in 2007 and approved in 2008.

• Waste Excavation and Transfer to Phase II

• Existing Liner System– Protective cover soil– LCRS Drainage Layer and 6 oz/sy Geotextile– 16 oz/sy Geotextile– HDPE Geomembrane/GCL

• Corrective Construction: Remove Side Slope Liner, Leak Detection Test on Basal Liner, and Restore/Repair Liner

• Clean Closure – Remove waste and impacted soils and all liner system components– Confirmation Sampling and Testing of subgrade– Geologic mapping and verification of bedrock– Install new liner and LCRS system– CQA

Corrective Action Workplan –Clean Closure Plan

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Key Points of Corrective Action Work Plan• Removal of wastes from the Phase I containment system, removal of the side

slope liner and basal liner

• The work plan will contain provisions for the following elements:

– Drawings and Technical Specs to implement Corrective Action

– Waste Management and Transportation Plan

– Cost estimate comparison of corrective action options

– Verification plan describing confirmatory sampling protocols

– Long-term monitoring plan (including air and stormwater monitoring)

– O&M plan for the landfill operations during implementation of the Corrective Action Plan

– Health and Safety Plan for project specific hazards

– Implementation Schedule

• RWQCB/LEA approved Clean Closure Work Plan in December 2012

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Phase I Clean Closure Design

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Phase I Reconstruct Design Report

• Design of the new cell in accordance with the prescriptive requirements of California Title 27 regulations and issued WDRs, removal of the waste and liner system present in the cell, and reconstruction of the new Phase I cell.

• Reconstruction design elements (stability analysis, LCRS design calculations, drainage analysis)

• Liner system: 24 inches compacted clay liner and 60 mil HDPE geomembrane liner

• LCRS drainage layer, subdrains, stormwater management, erosion control, interim and final slope stability

• Drawings and Technical Specifications

• CQA Plan

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Phase I Clean Closure Design

Phase I Clean Closure Construction

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Clean Closure Construction Schedule

• July 2013 – Phase II cell constructed and approved for waste placement (Phase I waste)

• Phase I Clean Closure between July 2013 –November 2013

• Provided Engineering Services During Construction and CQA services for Phase I corrective action construction between May 27, 2014 and December 2014 – over excavation, backfill, geological mapping and subdrain location

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Controls During Waste Removal

• Traffic control

• Health and Safety Plan

• Potential Tritium exposure

• Dust Control

• Odor Control

• Storm water and Erosion Control

• ADC Daily Cover

• Initial Waste Placement and Protection of Phase II liner

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Overview of Phase I and II

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Phase I and II Interface Preparation

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Phase I Excavation: Excavators Loading Trucks with Waste on West End

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Waste Placement on Lined Phase II (West End of Phase II)

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Dust Control and Daily Cover with ADC

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Phase I Liner Removal

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Subgrade Excavation

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Subgrade –Clean Closure Completed

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Demonstration of Clean Closure• Removal of Wastes and Contaminated Soils from

Phase I WMU

– Approximately 310,530 cy of waste and 60,720 cy cover soil were transferred to Phase II WMU

– Rate of removal 3,800 cy/day

– July 9, 2013 – November 26, 2013

• Removal of composite liner and LCRS

– throughout the Phase I waste excavation activities, the existing Phase I side slope (4.9 acres) and base liner (3.1 acres) system was removed and shredded and placed in the center of the fill cell of the Phase II WMU.

• Construction of interim storm water control measures

• Investigation of the Phase I side slopes and base subgrade for evidence of waste or leachate release by collecting and analyzing subgrade soil samples

• Photographic logs, field reports, CQA observations, and RWQCB notifications

• Clean Closure Certification Report

• March 2014 RWQCB deems Phase I WMU cleanup and abatement completed and no further action.

• RWQCB approved completion of corrective action construction and the Design Report on March 27, 2014

Phase I Reconstruction

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Key Points of Phase I Reconstruction Design• Subdrain and subgrade construction – January –

February 2015

• Low Permeability Soil Processing – January-February 2015

• Low Permeability Soil Test Cell and Test Pad –March 2015

• Sealed Double Ring Infiltration (SDRI) Test : March 2015

• Phase I liner reconstruction completed November 21, 2015– Low permeability soil– Geomembrane– Geotextile– LCRS Drainage Layer– Protective Cover Soil– Protective Plastic and Anchor Ballast

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Low-Permeability Soil

Borrow Material

Low-Permeability Soil Processing

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Low Permeability Soil Layer

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Geosynthetic Material Installation

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Leak Detection Testing

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LCRS Installation

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Construction Completion

Guides should be kept on for proper alignment within the grid structure.

Thank You

Authors:

CH2M: Marielle Coquia and Dan Jankly