CIVIL ENGINEERING LANDFILL APPLICATIONS USING TDA

PRESENTED BY:

Joaquin Wright, GHD Inc.on Behalf of CalRecycle

CalRecycle’s objective is to educate and promote TDA uses and benefits in Civil Engineering Applications

• Educate Local Public Works, CALTRANS, Private

Consulting Civil Engineers and State and Local

Environmental Agencies on the benefits of TDA

• Research – Develop Sustainable, Environmental

Beneficial and Cost Effective Civil Engineering Reuses for

Waste Tires

• Coordinate and Assist Waste Tire Processors to assure

there is adequate TDA to meet future demand.

Uses for Tire Derived Aggregate

• Lightweight fill for Embankments

• Lightweight fill for Slide Repair

• Lightweight backfill for Retaining Walls

• TDA used in Vibration Mitigation Applications

• TDA in Landfill Applications!

Beneficial Properties of Tire Derived Aggregate (TDA) in Civil Engineering Applications

• Tire Derived Aggregate (TDA) has properties that civil

engineers, public works directors & contractors need

– Lightweight

– Free Draining/High Permeability

– Low earth pressure

– Good thermal insulation

– Durable

– Compressible

– May be cheapest solution

– Help solve significant environmental problems

– Conserve natural aggregate resources

TDA in Landfills Applications

• Leachate Percolation/Injection trench Systems

• Drainage Layers in Landfill Covers, permeable Ops layers

• Horizontal and Vertical Landfill Gas Extraction

Trenches/wells

• Wet Weather Pad

Why use TDA in Landfill systems

• High Permeability/Free Draining, up to twice that of gravel

• Compressible, prevents pinching in settlement areas

• Cost savings, often is most cost effective material to import

• Reduced carbon footprint associated with TDA projects

• Recycling (100 Tires = 1.5 cy)

LFG TDA Recirculation Trench Construction

Kiefer Landfill, Leachate Recirculation and

Gas Extraction trench design for Bioreactor

landfill operation

LFG TDA Recirculation Trench Construction

Typical Trench Construction Welding of leachate injection pipe

LFG TDA Recirculation Trench Construction

Trench extraction and recirculation lines installed Trench completed and Buried

LFG TDA Trenches Typical Construction

• Typical Excavation & Relocation

of Refuse

• Typical equipment, End Dump,

Excavator, Skip loader, Air

Monitor

Landfill Gas Collection Trenches, Replace Gravel with TDA

• Geo-Textile Separator Between

TDA and Soil or Fine Material

Landfill Wet Weather Pad Construction using TDA

Landfill Wet Weather Pad Construction using TDA

• TDA Subgrade layer providesdrainage

• Crushed concrete / Brick Provides bulk driving surface

• Roofing tile pieces on top finish the driving surface

TDA use in Badlands Landfill, Moreno Valley, ca

Horizontal trench media behavior characteristics in landfill gas collection systems.

Tire derived Aggregate (TDA) and gravel empirical flow and constituent analysis at

Badlands Landfill in Riverside County, Ca.

Site Description

BADLANDS

SANITARY

LANDFILL

TO MORENOVALLEY

Well ID Final Trench Length (feet) Drainage Backfill MaterialsHW-23 800 gravelHW-24 920 TDAHW-25 800 TDAHW-26 700 gravelHW-27 715 TDA

Description of sampling and monitoring activities

• Eight bi-monthly sampling and monitoring events were performed over a four month period

(July 2012 through October 2012). Specific goals related to the monitoring and sampling

of LFG in the horizontal wells included determining relative hydraulic efficiency and relative

constituent analysis comparison.

– Air flow for each type of trench was recorded and compared. Horizontal wells were in operation and valves were

in variable open positions.

• When well flow was normalized to the valves being 100% open it indicated that the TDA constructed wells have the potential for

higher flow rates than the aggregate wells.

– Constituent analysis of historical testing regime for landfill

• Constituent comparison showed little variability, indicating that TDA did not have a significant impact on constituent loads

Air Flow

When the air flow valves for the studied wells were normalized to 100% open it indicated that

the TDA constructed wells have the potential for higher flow rates than the aggregate wells.

Average Air Flow (Normalized ) vs. Sample Event Date in HM-23 through HW-26.

0

20

40

60

80

100

120

140

160

180

200

TDA Gravel

Date

Cu

bic

Fe

et/

Min

ute

Vertical strain

• At the time of the study the approximate landfill burial depths of the horizontal wells ranged

from 66 to 84 feet. Holding lateral strain and dampening effects constant, the maximum

estimated range of vertical strain in the Badlands TDA trenches(under an approximate

average of 75 feet of fill) ranges from 25-50%. Assuming that TDA begins with

approximately 63% porosity then a 25-50% vertical strain results in approximately 31-47%

remaining porosity with the TDA horizontal wells.

• For this study; using only vertical stresses, and an approximate average of 75 feet of

landfill materials overlying the trenches, then the resulting maximum theoretical vertical

strain on the horizontal well trenches is:

• 75 ft x 44.44 lbs/ft3 = 3,333.3 lb/ft2 = 23 lb/in2 (psi) or 160 kilopascals (kPa)

Vertical strain

LFG Constituents

Under normal operating conditions, average LFG measurements collected in the field

(methane, carbon dioxide, and oxygen) were similar to that expected within solid waste

landfills and similar in quantities and overall patterns to historical Badlands Landfill data for

both the TDA and aggregate constructed wells. The eight sampling events were enough to

show general trends in typical constituents and flow rates for both horizontal well types, TDA

and gravel.

Chemical analyses for the LFG air samples included:

Fixed Gases by ASTM 1946D Test Method;

and, Volatile Hydrocarbons and Sulfur Compounds by EPA Test Method TO-15.

LFG Constituents

Methane measurements were collected from HW-23 through HW-27 during field activities

from a GEM 2000+ LFG field instrument. The average percent methane measured in TDA

wells and gravel wells are indicated on the chart below. The average percentage of methane

measured in both types of wells are comparable to each other and fall within the expected

range of methane (approximately ±45-60%) within landfills.

0

10

20

30

40

50

60

70

80

90

100

Average TDA Methane

Average Gravel Methane

Average Percent Methane in TDA Wells vs. Average Percent Methane

in Gravel Wells

%M

eth

ane

Date

Summary

• The data analysis supports the finding that the horizontal landfill gas collection wells using

TDA as the pipe bedding perform the same as, if not better, than historical gravel bedding

material in regards to hydraulic efficiency in landfill gas collection trench systems.

• The resulting data from the LFG Sampling and Constituent Analysis indicates that in the

given landfill site and locations, the TDA well trenches perform the same or better than the

typical gravel well trenches historically used to extract LFG.

TDA Grant Program Overview

• Eligible Projects/Categories

– Lightweight fill

– Landfill applications!

– Retaining wall backfill

– Vibration mitigation

TDA Grant Program Overview

• Project Requirements

– 100% CA-generated waste tires

– Minimum 500 tons of TDA materials

– Landfill projects must not use more than 0.75 ton of TDA per

lineal foot of landfill gas collection or leachate injection system

– Plans and specifications are subject to review by CalRecycle’s

engineering staff

– Technical assistance/training will be provided by CalRecycle

contractors and/or staff

TDA Grant Program Overview

• Eligible Cost (up to $350k)

– TDA material & delivery

– Installation

– Testing

– Engineering/Design Work

TDA Grant Program Overview

If you have technical questionsplease contact us!

Joaquin Wright at (707) 303-4850,

e-mail: joaquin.wright@ghd.com

or

Stacey Patenaude at (916) 341-6418,

e-mail: Stacey.patenaude@calrecycle.ca.gov