EXAMINATION OF MODERN SANITARY LANDFILLS

W. Gregory VogtChair, Sanitary Landfill Working Group, ISWA

Vice President, SCS Engineers

Major Challenges

Acceptance and Approvals for:

– Facility Expansions

– Siting New Facilities

Operational Practices

Regulatory Enforcement

Expansions and New Facilities

Few New Sites Receive Approvals

Public is More Organized Against But Understands the Need

Large Expansions and Quarry Fills

Stabilization Concerns

Expansions and New FacilitiesClosure of Poorly Located Sites Large, New Regional Facilities,

Larger Equipment, Rail AccessLeachate Recirculation Combined

with Better CompactionNew Landfills Atop Old LandfillsNew Structures Atop Old Landfills

Biogas Migration Protection

Robust Foundation Designs

California Office Park

Operating Practices

Control of Moisture (Liquids)Promoting Run-offWork AreasCover ApplicationWeather IssuesProblem WastesEnvironmental Controls (Birds, Dust,

Litter, Vectors, Odor)Landfill Biogas

Moisture Control

Keep Liquid Wastes OutGood CompactionReach Final Elevation QuicklyApply Effective Intermediate and

Final Cover

Waste In Trench Landfill

Trench landfills not approved in most countries

Ponding

. . . Infiltrates the waste mass

Ponding Causes Leachate

Promote Run-Off

Eliminate Ponding (Depressions)

Divert Water From Wastes

Control Run-On

Run-on/Run-off Controls

Run-on/Run-off Controls

Run-off Control

. . . By Grade Breaks

Stormwater Interception

. . . Direct Run-off

Flooded Cell

. . . Requires Pumping

Don’t Forget Road Drainage

Run-Off to Sediment Basin

Basin With Run-off

Slope Erosion

. . . Collected

Basin Collects Sediment

Erosion Control — Silt Fence

. . . Impacting Working Face and Compaction

Erosion Control — Rip-rap Ditch

Erosion Control — Jute Matting

Management of Work Areas

Controlled Working Face

Compaction

Cell Construction

Uncontrolled Working Face

Poor Compactor Practice

Small Working Face

Compaction

Generally Work Up The Slope

Keep Layers To 1 Meter - Loose

Maintain Proper Slope

– 3:1 (Horiz: Vert) Maximum

Efficiency: 3 - 5 Passes

Compaction Efficiency - Depth

Thickness of Layer

Compaction Efficiency With Number Of Passes

Number of Passes

Cell Construction

Layer Thickness

Cell Construction

Working Face Cover

Cell Construction

Layer Thickness

Landfill Cover

Daily

Alternative Daily Covers

Intermediate

Final

Daily Cover

Sanitary Landfill Requires

– Control Litter, Odors and Vermin

– Fire Protection

Generally 15 cm Compacted Soil

Forget the Daily Cover?

Daily Soil Cover

Stockpile . . . Even in the Winter

Alternate Daily Cover (ADC)

FoamsSlurriesBlankets/TarpsShredded Waste (e.g., Tires)Ash and ResiduesContaminated Soils Compost

ADC — Foam Daily Cover

Tarp — On Roller

. . . Note Assistant

Tarp Roller

Attachment to Compactor

Intermediate Cover

The Same As Daily Cover Plus:

– At Least 0.3 meters (Soil)

– Reduce Infiltration

– Control Gas Migration

– Provide “Operating” Surface

Final Cover

As Specified In Permit

Final Control of Infiltration and Gas

Support Vegetative Growth

Landfill Biogas

Monitoring Wells

Biogas Sampling Well

Gas Monitoring Well

Methane and Biogas Meter

Methane Sample Instrument

Biogas Management Options

Venting to Atmosphere

Flare Burning

Incineration (Controlled Process)

Recovery as an Energy Source

Active Biogas Control

Gas Well Connected to Collection Pipe

Active Collection System

Biogas Extraction Well

Active Biogas Systems

Collection Pipe With Supports

. . . Water is Maintenance Item

Active Biogas Systems

Blower for Vacuum

Active Biogas Extraction

Blowers and Controls

Passive Biogas Systems

Passive Biogas Systems

Open Pipe Vented to Atmosphere

Potential for Biogas Recovery

1,000,000 Tons of Waste Minimum

Site Closed Less Than 5 Years

12 meters Minimum Average Depth

Impermeable Cover

LFG Use Options

Sale of Generated Electricity

Sale as Natural Gas Alternative

Burn in Flare

Value of Carbon Credits

Electricity From Biogas

Large Equipment

Electric Power Units

. . . Or Portable Units

Burn in Flare

No Treatment

No Energy Recovery

Still Requires Water Removal

Enclosed Flare & Candle Flare

Regulatory Enforcement Documents

Permits

Approved Plans and Specifications

Variances

Compliance Agreements

Types of Plans

Design Plans - Design Engineer

Operating Plans - Landfill Manager

Summary

Gain Acceptance from the Public Through Use of Good Engineering Design and Regulatory Compliance

Design and Operations Must Address Control of All Landfill Issues (odors, contamination)

Regulators, Inspectors, and Landfill Operators Should Receive Training