Comparison of Environmental Impacts of Wood Treated with Three Different Arsenic-Free Preservatives and CCA CCA-TAG Meeting B. Dubey 1, T. Townsend 1,

Comparison of Environmental Comparison of Environmental Impacts of Wood Treated with Impacts of Wood Treated with Three Three Different Arsenic-Free Preservatives Different Arsenic-Free Preservatives

and and CCACCA

CCA-TAG MeetingCCA-TAG Meeting

B. DubeyB. Dubey11, T. Townsend, T. Townsend11, H. Solo-Gabriele, H. Solo-Gabriele22

11University of Florida, Dept. of Environ. Eng. SciencesUniversity of Florida, Dept. of Environ. Eng. Sciences22University of Miami, Dept. of Civil, Arch. And Environ University of Miami, Dept. of Civil, Arch. And Environ

EngineeringEngineering

August 18, 2005

Research ObjectiveResearch Objective

Compare and contrast the potential Compare and contrast the potential environmental impact of wood treated with environmental impact of wood treated with arsenic and chromium free preservatives arsenic and chromium free preservatives with that from CCA-treated wood with that from CCA-treated wood

Specific ObjectivesSpecific Objectives

1.1. Leachate characterization for heavy Leachate characterization for heavy metals in the leachate produced on co-metals in the leachate produced on co-disposal of pressure-treated wood in C&D disposal of pressure-treated wood in C&D and MSW landfill environmentand MSW landfill environment

2.2. Impact of surface water conditions on Impact of surface water conditions on chemical leaching and aquatic toxicity of chemical leaching and aquatic toxicity of pressure-treated wood pressure-treated wood

3.3. Impact on soil from pressure- treated Impact on soil from pressure- treated wood leachateswood leachates

Pressure Treated Wood Being Pressure Treated Wood Being EvaluatedEvaluated

• ACQ : Alkaline Copper QuaternaryACQ : Alkaline Copper Quaternary• CBA : Copper Boron AzoleCBA : Copper Boron Azole• DOT : Disodium Octaborate DOT : Disodium Octaborate

Tetrahydrate Tetrahydrate • CCA : Chromated Copper ArsenateCCA : Chromated Copper Arsenate

Leachate characterization for heavy Leachate characterization for heavy metals in the leachate produced on co-metals in the leachate produced on co-disposal of pressure-treated wood in disposal of pressure-treated wood in C&D and MSW environmentC&D and MSW environment

-Simulated C&D landfill environment-Simulated C&D landfill environment

-Leaching with MSW leachate-Leaching with MSW leachate

Disposal ScenariosDisposal Scenarios

The county provideda large area near apaved road for locating the lysimeters.

The driller used a 3-ft bucket auger.

The hole prior to lysimeter installation. 15 ft deep.

The annulus of the holes was backfilled with sand.

Thermocouple wires were included for temperature measurement.

Waste Composition for Simulated C&D Landfill Waste Composition for Simulated C&D Landfill

33%

30%

14%

12%

8%

1% 1%1%

UT Wood

Concrete

Roofing

Drywall

Cardboard

Ferrous

Insulation

Steel

Waste Composition for Co-disposal of ACQ in Waste Composition for Co-disposal of ACQ in Simulated C&D LandfillSimulated C&D Landfill

5%1%

5%

23%

29%

14%

12%

8%

1% 1%1%

LBP

Hg Lamp

ACQ

UT Wood

Concrete

Roofing

Drywall

Cardboard

Non Ferrous

Insulation

Steel

Waste Composition for Co-disposal of CCA in Waste Composition for Co-disposal of CCA in Simulated C&D LandfillSimulated C&D Landfill

5%1%

5%

23%

29%

14%

12%

8%

1%

1%1%

LBPHg LampCCAUT WoodConcreteRoofingDrywallCardboardNon FerrousInsulationSteel

Cutting wood into smaller pieces

ACQLead based paintCCA

Loading the ColumnLoading the Column

C&D Lysimeters

C&D LBP, CCA, Hg lamps

• Wood blocks added during mixing

• Wood blocks throughout lysimeter

• Hg lamps were broken inside lysimeter, starting after first lift

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

LBP, CCA

River Rock

LBP, CCA

LBP, CCA

Hg lamps

C&D LBP, ACQ, Hg lamps

• Same as C&D lysimeter with CCA wood, but ACQ treated wood used instead. LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

LBP, ACQ

River Rock

LBP, ACQ

LBP, ACQ

Hg lamps

Compacting the WasteCompacting the Waste

Water addition

Filling sampling bottles

Aug Oct Dec Feb Apr Jun

pH

5.0

5.5

6.0

6.5

7.0

7.5

8.0

C&D Control C&D CCA C&D ACQ

Dec Jan Feb Mar Apr May Jun Jul

OR

P

-300

-250

-200

-150

-100

-50

0

C&D Control C&D CCA C&D ACQ

9/1/04 11/1/04 1/1/05 3/1/05 5/1/05 7/1/05

Ars

enic

(m

g/L

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

C&D Control C&D CCA C&D ACQ

9/1/04 11/1/04 1/1/05 3/1/05 5/1/05 7/1/05

Ch

rom

ium

(m

g/L

)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

C&D Control C&D CCA C&D ACQ

9/1/04 11/1/04 1/1/05 3/1/05 5/1/05 7/1/05

Bo

ron

(m

g/L

)

0

2

4

6

8

10

12

14

C&D Control C&D CCA C&D ACQ

• Copper was below detect in all three C&D column leachates throughout the duration of experiment

Batch Test Results

• Blocks of CCA and ACQ were leached in leachates from the control columns.

• The results were compared to results from leaching blocks using the TCLP and SPLP.

Sawdust

TCLP SPLP C&D Leachate0

2

4

6

8

10

12

14

TCLP SPLP C&D Leachate

Co

nce

ntr

atio

n (

mg

/L)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0100 gm Blocks

Arsenic Copper Chromium

As

Cu

Cr

Leaching of CCA Blocks

100 gm Blocks

TCLP SPLP C&D Leachate

Co

ncen

trati

on

(m

g/L

)

0

2

4

6

8

10

Copper Boron

TCLP SPLP C&D Leachate0

10

20

30

40

50

60Sawdust

Leaching of ACQ Blocks

Copper

Boron

• Minimal leaching of copper observed suggesting that disposal of copper-based wood preservatives posses minimal impact to groundwater from copper leaching

• What will happen if the landfill gets aerobic over a long period??

Leaching of treated wood sawdust Leaching of treated wood sawdust with MSW landfill leachatewith MSW landfill leachate

• Sawdust samples of CCA, ACQ, CBA and Borate treated wood was prepared from treated wood lumber

• 26 MSW landfill leachate samples were collected to use as the leaching fluid

• Batch leaching test of TCLP, SPLP and WET was also conducted for comparison

Solid Waste Size Reduce toLess Than 1 cm

Leach 100 g for 18 hours at 30 RPM

Filter Solidsfrom Leachate

Analyze Leachate

X mg/L

MSW TCLP SPLP WET

Co

nc

en

tra

tio

n (

mg

/L)

0.1

1

10

100

As Cr Cu CCA

MSW TCLP SPLP WET

Co

nce

ntr

atio

n (

mg

/L)

1

10

100

Cu B ACQ

CBA

MSW TCLP SPLP WET

Co

nce

ntr

atio

n (

mg

/L)

10

100

Cu B

Borate

MSW TCLP SPLP WET

Co

nc

en

tra

tio

n (

mg

/L)

0

20

40

60

80

100

120

140

160Boron

Summary of results for MSW Summary of results for MSW leaching studyleaching study

• Metals leach from pressure treated wood when leached with landfill leachate

• Leaching concentrations from the pressure treated wood vary with leachate quality

• Results indicate that the co-disposal of treated wood with municipal solid waste could impact the leachate quality

Impact of surface water conditions Impact of surface water conditions on chemical leaching and aquatic on chemical leaching and aquatic toxicity of pressure-treated woodtoxicity of pressure-treated wood

Parameters being measuredParameters being measured

• Total copper, free copper and toxicity Total copper, free copper and toxicity analysis using MetPlate and Algal analysis using MetPlate and Algal assay will be performed on each wood assay will be performed on each wood block leachateblock leachate

• Samples will also be analyzed for Samples will also be analyzed for TOC, TDS, alkalinity and anionsTOC, TDS, alkalinity and anions

Some preliminary leaching dataSome preliminary leaching data

Average Total Copper (mg/L) Aquatic Toxicity EC50 (%)

Final pH Sample Type

DI NW-1 NW-2 DI NW-1 NW-2 DI NW-1 NW-2

CCA 1.50 0.25 0.46 9.3 68.8 35.3 5.38 6.89 5.51 ACQ 5.25 3.05 3.63 10.0 27.2 24.5 5.98 6.81 6.09 CBA 20.5 12.7 16.5 2.7 9.4 6.4 6.07 6.65 5.81

Impact on soil from pressure- Impact on soil from pressure- treated wood leachatestreated wood leachates

Decks have been set up at Solar Energy Research Park, UF

Soil column in lab with three soils

Parameters being analyzed

• Preservative components, pH, ORP, Conductivity in leachate and soil

• Soil samples being characterized for pH, OM, CEC, Grain size distribution etc.

In summary

• Out of 4 experiments comparing the treated wood, two have been completed and two are underway

• Results from uncompleted experiments will be updated in the subsequent meetings

Questions?Questions?