cca-tag meeting
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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 , H. Solo-Gabriele 2 1 University of Florida, Dept. of Environ. Eng. Sciences - PowerPoint PPT PresentationTRANSCRIPT
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-Gabriele2211University of Florida, Dept. of Environ. Eng. SciencesUniversity of Florida, Dept. of Environ. Eng. Sciences
22University 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 WoodConcreteRoofingDrywallCardboardFerrousInsulationSteel
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%
LBPHg LampACQUT WoodConcreteRoofingDrywallCardboardNon FerrousInsulationSteel
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
(mg/
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
Chr
omiu
m (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
Bor
on (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
Con
cent
ratio
n (m
g/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
Con
cent
ratio
n (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 LeachateX mg/L
MSW TCLP SPLP WET
Con
cent
ratio
n (m
g/L)
0.1
1
10
100As Cr Cu
CCA
MSW TCLP SPLP WET
Con
cent
ratio
n (m
g/L)
1
10
100
Cu B ACQ
CBA
MSW TCLP SPLP WET
Con
cent
ratio
n (m
g/L)
10
100
Cu B
Borate
MSW TCLP SPLP WET
Con
cent
ratio
n (m
g/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?