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 CCA CCA CCA-TAG Meeting CCA-TAG Meeting B. Dubey B. Dubey 1 , T. Townsend , T. Townsend 1 , H. Solo-Gabriele , H. Solo-Gabriele 2 1 University of Florida, Dept. of Environ. Eng. University of Florida, Dept. of Environ. Eng. Sciences Sciences 2 University of Miami, Dept. of Civil, Arch. And University of Miami, Dept. of Civil, Arch. And Environ Engineering Environ Engineering August 18, 2005
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Comparison of Environmental Impacts of Wood Treated with Three Different Arsenic-Free Preservatives and CCA CCA-TAG Meeting B. Dubey 1, T. Townsend 1,
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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
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
• 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 (%)