Wood Preserving Objectives

Transcription

1 Wood Preserving

2 Wood Preserving Objectives List three major chemical preservative systems List key chemicals associated with wood preserving Describe the pressure treating process List major modes of release to the environment Identify analytical methods useful for detecting wood preservative contaminants in the environment

3 Wood Preserving Overview Active in U.S. for over 100 years Produces treated lumber and wood products which resist degradation High percentage of small businesses Many facilities closed, abandoned or failed to comply with new industry-specific RCRA regulations (1990) wastewaters listed as hazardous waste Drip pads and other improvements required

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5 Process Overview SIC: 2491, NAICS Used by construction, railroad, and utilities industries 6.5 billion board ft / yr (2000) 486 U.S. facilities (1992) 307 employ 20 or fewer 90% by pressure treating process

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7 Major Chemical Preservative Systems Organic (oil-borne) Creosote (15%) Pentachlorophenol (PCP) (6%) systems Inorganic (water-borne) (78%) Chromated copper arsenate Ammoniacal copper-zinc-arsenate (ACZA) Ammoniacal copper arsenate (ACA) Ammoniacal copper quarternary (ACQ)

8 Video Chemical Preservatives

9 Key Chemicals Arsenic - CCA constituent, toxic and prevalent Oil diluent/lubricant/fuel, contains VOC s, including BTEX Creosote preservative, mixture of SVOC s, a.k.a. cancer in a bucket Chromium CCA constituent, toxic (especially Cr +6 ) PCP preservative, chlorinated SVOC, solid unless oil-borne Zinc ACZA constituent, less toxic, less prevalent Dioxins / furans toxic chlorinated SVOC family, 2,3,7,8-TCDD Godfather Copper CCA constituent Diesel oil preservative diluent

10 Standard Process Schematic VACUUM & BOILER EMISSIONS, BLOWDOWN, VOCs, AMMONIA, AIRBORNE ARSENICS, ETC UNTREATED LUMBER, PCP, CREOSOTE, CCA, ETC. RM P TREATED LUMBER STEAM, DIESEL OIL, COAL TAR, PETROLEUM OIL, ETC. R CHROMIUM, PAHs, ARSENIC, ZINC B W PCP, CREOSOTE, CCA (RECYCLED) CONTAMINATED DEBRIS, FILTERS, METAL- BEARING SLUDGE, ORGANIC SLUDGE, SPENT CARBON

11 Pressure Treating Process Details Vent High Pressure pump Working solution Concentrate Storage of freshly treated wood Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Paved containment area Process Water Tanker Line Sump Charging area Drip pad Curbs

12 CCA Process Description - Bethell or Full-Cell Process Vent Concentrate 50 60% CCA Transfer line Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Charging area Drip pad Curbs 12

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14 Video Drying Methods

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16 Video Retort

17 Step 1: Preparation Vent Concentrate Transfer line Retort Cylinder Vacuum pump Storage of freshly treated wood High Pressure pump Working solution Effluent Exterior Loading Drainage Filters Paved containment area Sump Charging area Drip pad Curbs 17

18 Step 1: Preparation Vent 1 2% CCA Mold Inhibitor Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Process water Drip pad Charging area Pressure = 1 atm Temperature = 70 F Curbs 18

19 Vent Step 2: Vacuum High Pressure pump Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Process Water Tanker Line Drip pad Charging area Pressure = ~3 in Hg absolute Temperature = 70 F Curbs 19

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21 Step 3: Pressurization Vent High Pressure pump Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Process Water Tanker Line Drip pad Charging area Pressure = 175 psi (5-8 min.) Temperature = 70 F Curbs 21

22 Step 4: Depressurization Vent Working solution High Pressure pump Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Process Water Tanker Line Curbs Drip pad Charging area Pressure = 175 psi to 1 atm (up to 2 hours) Temperature = 70 F 22

23 Step 5: Final Vacuum Vent Working solution High Pressure pump Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Vacuum pump Drainage Retort Cylinder Exterior Loading Effluent Filters Paved containment area Process Water Tanker Line Drip pad Charging area Pressure = 1 atm to 20 in Hg Temperature = 70 F Curbs 23

24 Step 6: Charge Unloading Vent Working solution High Pressure pump Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Process Water Tanker Line Drip pad Charging area Pressure = 1 atm Temperature = 70 F Curbs 24

25 Step 7: Repeat the Cycle Vent Working solution High Pressure pump Concentrate Working Transfer line Solution Storage of freshly treated wood Sump Drainage Vacuum pump Retort Cylinder Exterior Loading Effluent Filters Paved containment area Curbs Drip pad Charging area Pressure = 1 atm Temperature = 70 F 25

26 CCA and ACZA Formulations Compound (%) Preservative Chromium (VI) as CrO 3 Copper as CuO Zinc as ZnO Arsenic as As 2 O 5 CCA Type A Standard Range Type B Standard Range Type C Standard Range ACZA Standard Range Source: American Wood Preserver s Association, 1992

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28 Composition of Commercial Grade and Purified Grade Pentachlorophenol Component Pentachlorophenol Tetrachlorophenol Trichlorophenol Chlorinated phenoxyphenol Octachlorodioxin Heptachlorodioxin Hexachlorodioxin Octachlorodibenzofuran Heptachlorodibenzofuran Hexachlorodibenzofuran Commercial (Dowcide 7) Analytical Results 88.4% 4.4% 0.1% 6.2% 2500 ppm 125ppm 4 ppm 80 ppm 80 ppm 30 ppm Purified (Dowcide EC-7) 89.8% 10.1% 0.1% --% 15 ppm 6.5ppm 1 ppm 1 ppm 1.8 ppm 1 ppm Source: EPA 1978

29 Technical PCP Constituents Cl OH Cl 85 90% Cl OH O Cl Cl Cl 2 6% Cl Cl Cl Pentachlorophenol Cl Cl Cl Cl Cl Higher chlorophenols Cl OH Cl 4 8% Cl Cl O Cl Cl ~ 0.1% Cl Cl O Cl Cl Cl 2,3,5,6 - Tetrachlorophenol Dioxin (octa, traces of hepta, and hexachlorodioxin) Cl

30 Major Chemical Components of Creosote Produced in the U.S. Compound or Component Percentage* Naphthalene Methyl naphthalene Diphenyl dimethylnaphthalene -- Biphenyl Acenaphthene Dimethylnaphthalene 2.0 Diphenyloxide -- Dibenzofuran 5.0 Fluorene-related compounds Source: EPA 1990, 1992 Compound or Component Percentage* Methyl Fluorene 3.0 Phenanthrene 21.0 Anthracene 2.0 Carbazole Methylphenanthrene 3.0 Methylanthracenes 4.0 Fluoranthene Pyrene 8.5 Benzofluorene 2.0 Chrysene 3.0 *Volume may vary significantly

31 Structure of the Major Components of Creosote Naphthalene Phenanthrene CH 2 CH 2 Fluoranthene Acenaphthene Pyrene

32 Physical Properties of Creosote Compounds Compound Molecular Weight Solubility 20 C) Specific Gravity Vapor Pressure* (torr) Boiling Point ( C) Benzene mg/l Naphthalene mg/l Pyrene mg/l x Chrysene mg/l x Benzo(a) Anthracene mg/l n/a 1.1 x 10-7 n/a 20 C. Source: Superfund Chemical Data Matrix for Windows, version 1.0, September 1997

33 Video Wastewater F Codes

34 Modes of Release - Hazardous Waste Streams Wastewaters (ww), process residuals, drippage F032 - PCP processes F034 - Creosote processes F035 - Inorganic preservatives K001 - Bottom sediment sludge from ww processes for creosote and / or PCP facilities

35 Video Wastewaters

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38 Modes of Release - Typical Hazardous Waste Composition Waste Description: K001-C (Creosote type) Allied Chemical s Birmingham, AL Plant, Bottom Sediment Sludge Analysis: Soil 30.0% Water 20.0 Wood Chips 10.0 Naphthalene 4.0 Phenanthrene 3.5 Fluoranthene 2.5 Other active organics % Ash content 12 51% Heating value 10,000 11,000 BTU/lb Volatile matter 57 81%

39 Modes of Release - Typical Hazardous Waste Composition Waste Description: K001-C Pentachlorophenol (PCP) Type Allied Chemical s Richton MS Plant, Bottom, Sediment Sludge Analysis: Soil 40.0% Water 30.0 Wood Chips 10.0 Active organics* % Ash content 12 51% Heating value 3,800 8,300 BTU/lb PCP 970 3,800 ppm *Tetra- and pentachlorophenols, benzene, toulene, and PAHs

40 Modes of Release Other Release Sources Retort outwash Drip pad / storage pad drippage, a.k.a. kick back Off-loading spills Stormwater runoff Discarded, unused commercial products (F027, U051, P011, etc.)

41 Video Kickback

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50 Modes of Release - Hazardous Waste Streams Characteristic wastes D004 - Arsenic D007 - Chromium D018 - Benzene D037 - PCP Discarded, unused commercial products F027 - PCP U051 - Creosote Inorganics, e.g., arsenic pentoxide

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52 Video Broken & Discarded Treated Lumber Pieces

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54 Analytical Considerations Laboratory Methods Inorganic Total metals: AA or ICP TCLP for RCRA characteristic Creosote Analyze for PAHs HPLC or GC / MS PCP SW / 8270 TCLP

55 Analytical Considerations Field Screening Methods Inorganic X-ray fluorescence (XRF) Organics Immunoassay test kits (PCP, PAH, TPH, etc.) Portable GC or GC/MS

56 Wood Preserving Summary List three major chemical preservative systems List key chemicals associated with wood preserving Describe the pressure treating process List major modes of release to the environment Identify analytical methods useful for detecting wood preservative contaminants in the environment