EPA/600/R-93/168
August 1993
WASTE MINIMIZATION PRACTICES
AT TWO CCA WOOD-TREATMENT PLANTS
by
Abraham S. C. Chen and Robert F. Olfenbuttel
Battelle
Columbus, Ohio 43201
Contract No. 68-CO-0003
Work Assignment No. 2-36
Project Officer
Paul Randall
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Recycled Paper
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NOTICE
This material has been funded wholly or in part by the U.S. Environmental
Protection Agency (U.S. EPA), under Contract No. 68-CO-0003 to Battelle. It has been
subjected to the Agency's peer and administrative review and approved for publication as a
U.S. EPA document. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. EPA or Battelle; nor does mention of trade names, commercial
products or treatment processes constitute endorsement or recommendation for use. This
document is intended as advisory guidance only to the CCA wood treaters in developing
approaches to waste reduction. Compliance with environmental and occupational safety and
health laws is the responsibility of each individual business and is not the focus of this
document.
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FOREWORD
Today's rapidly developing and changing technologies and industrial products and
practices frequently carry with them the increased generation of materials that, if improperly
dealt with, can threaten both public health and the environment. The U.S. Environmental
Protection Agency (EPA) is charged by Congress with protecting the Nation's land, air, and
water resources. Under a mandate of national environmental laws, the agency strives to
formulate and implement actions leading to a compatible balance between human activities
and the ability of natural systems to support and nurture life. These laws direct the EPA to
perform research to define our environmental problems, measure the impacts, and search for
solutions.
The Risk Reduction Engineering Laboratory is responsible for planning,
implementing, and managing research, development, and demonstration programs to provide
an authoritative, defensible engineering basis in support of the policies, programs, and
regulations of the EPA with respect to drinking water, wastewater, pesticides, toxic
substances, solid and hazardous wastes, Superfund-related activities, and pollution
prevention. This publication is one of the products of that research and provides a vital
communication link between the researcher and the user community.
Passage of the Pollution Prevention Act of 1990 marked a strong change in the
U.S. policies concerning the generation of hazardous and nonhazardous wastes. This bill
implements the national objective of pollution prevention by establishing a source reduction
program at the EPA and by assisting States in providing information and technical assistance
regarding source reduction. In support of the emphasis on pollution prevention, the "Waste
Reduction Innovative technology Evaluation (WRITE) Program" has been designed to identify,
evaluate, and/or demonstrate new ideas and technologies that lead to waste reduction. The
WRITE Program emphasizes source reduction and on-site recycling. These methods reduce or
eliminate transportation, handling, treatment, and disposal of hazardous materials in the
environment. The technology evaluation project discussed in this report emphasizes the
study and development of methods to reduce waste and prevent pollution.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
HI
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ABSTRACT
Two chromated copper arsenate (CCA) wood-treatment plants were assessed for
their waste minimization practices. These practices have been reflected in several areas,
including facility designs, process controls, and management practices. The objectives were
to estimate the amount of hazardous wastes that a well-designed and well-maintained CCA
treatment plant would generate, and to examine the possibility of pollution prevention and
waste reduction in a CCA plant. The information collected will be used to develop a pollution
prevention guide that will assist wood treaters in identifying ways to prevent pollution and
reduce wastes.
This assessment report was submitted in partial fulfillment of Contract Number 68-
CO-0003, Work Assignment 2-36, under the sponsorship of the U.S. Environmental
Protection Agency. This report covers a period from September 1992 to September 1993,
and the study was completed as of June 30, 1993.
IV
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CONTENTS
Notice ii
Foreword iii
Abstract iv
Acknowledgments viii
SECTION 1: Introduction 1
SECTION 2: Assessment Methodology 2
SECTION 3: Description of the Plants 5
Madison Wood Preservers, Inc 5
Old Treatment Plant 5
New Treatment Plant 5
Universal Forest Products, Inc., Hanson Treatment Facility 20
Overview of Wood-Treating Operations 20
Pressure Treatment Plant 20
SECTION 4: Waste Minimization Practices 31
Facility Designs 31
Enclosed Treatment Buildings 31
Covered Drip Pads and Drip Pan 31
Automatic Lumber Handling System and Power Rollers 32
Tank Farm and Spill Containments 33
Air Ventilation Systems 33
Process Controls 34
Management Practices 35
Pretreatment Quality Control 35
Improved Housekeeping 35
Resource Recovery and Recycling . . . 38
Operator Training 39
SECTION 5: Hazardous Wastes Generated 40
Hazardous Wastes Generated by Madison Wood Preservers 40
Hazardous Wastes Generated by Universal Forest Products Ranson Plant 40
SECTION 6: References 41
APPENDIX A: Waste Minimization Assessment Worksheets 42
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TABLES
Number
1 List of waste minimization assessment worksheets 4
2 Treatment conditions of typical pressure-treating processes 19
FIGURES
1 A side view of Madison Wood Preservers' new treatment plant 6
2 Madison Wood Preservers' new treatment plant layout 7
3 Flow diagram of wood-treating operations at Madison Wood Preservers 8
4 Lumber banding with plastic straps and wood crosspieces 9
5 Lumber end-squeezing 9
6 Lumber-handling system layout 11
7 Automatic chain conveying system and drip pan above the recessed floor
for lumber moving, drippage intercepting, and spill retaining, respectively 12
8 Two 7' x 100' treating cylinders on concrete piers above the recessed floor ... 13
9 Tank farm layout 14
10 Elevated CCA concentrate tank with cone-shaped bottom 15
11 Enclosed chemical mixing system with the large wax tote on the metal
stand, bag filter cartridge by the metal stand, and mold inhibitor drums
at the far end 16
12 Typical process flow diagram for a two-cylinder CCA pressure-treating
facility 18
13
The drying shed 19
VI
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FIGURES (continued)
Number Page
14 Ranson plant layout 21
15 Flow diagram of wood-treating operations at Ranson plant 22
16 Lumber restacking by a stacker 22
17 Lumber banding with plastic strap 23
18 Rain/trench system, lumber loading area, and chemical-covered drip pad or
conditioning area 24
19 Treatment plant layout at Ranson 25
20 Underground pits 26
21 Floor slab separating treating cylinder and underground pit and underground
CCA primary tank 27
22 Freshly treated lumber units on drip pad 28
23 Sludge, wood chips, and debris in trench 29
24 Two-screen setup for solid waste air drying 29
25 Cylinder door opened right after treatment 32
26 Tire marks on concrete floor as a result of forklift operations 36
27 Neatly stacked lumber units in the treatment plant 37
28 Chopped plastic banding stored in large cardboard boxes for recycling 38
29 Stack of 1' x 2' lattice produced from wood trims and strips from milling
operations 39
VII
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ACKNOWLEDGMENTS
The U.S. Environmental Protection Agency and Battelle acknowledge the important
contribution made by Michael Charles of the American Wood Preservers' Institute, in
identifying and recommending two CCA treatment plants for this assessment project. William
Price, president of Madison Wood Preservers, Inc. at Madison, Virginia, and Joe Granger,
General Manager of Universal Forest Products Ranson Plant at Ranson, West Virginia, are
acknowledged for providing support for the on-site assessment, and for reviewing this
assessment report. Ian Stalker, Vice President of Universal Forest Products, also reviewed
this report. Additional reviewers include S. Garry Howell of the U.S. Environmental
Protection Agency; Darrel Nicholson of Mississippi State University, Mississippi Forest
Products Laboratory; and Rodney De Groot of the U.S. Department of Agriculture, Forest
Products Laboratory in Madison, Wisconsin.
VIII
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SECTION 1
INTRODUCTION
The wood-treatment industry uses about 70% of the arsenic consumed in the
United States (Loebenstein, 1991; 1992). Most of this is used to produce chromated copper
arsenate (CCA). Different formulations of CCA have been known as some of the most
effective wood preservatives for the treatment of lumber, timber, and other wood products
for aboveground and ground-contact applications. However, because of the toxicity and
carcinogenicity of arsenic and chromium, CCA may pose potential threats to human health
and the environment.
The U.S. Environmental Protection Agency (EPA) is currently evaluating the waste
reduction and pollution prevention potential of an alternative wood preservative system. This
evaluation project is part of the ongoing Resource Conservation and Recovery Act (RCRA)
Problem Wastes Technology Evaluation Program. The program evaluates, in typical industrial
and agricultural workplace environments, innovative technologies that demonstrate a
potential to either reduce or eliminate the use of RCRA metals, including arsenic, or to
minimize the RCRA problem wastes through recycling and recovery.
The evaluation will be performed at one wood treatment plant having side-by-side
treatment capabilities for CCA and the alternative preservative system. However, the site
selected for that study may not represent the best case or even a good example of efficient
use of CCA. For comparison, EPA asked that CCA use be investigated at two other sites
identified by an industry trade group as having excellent management practices (inventory
control, spill prevention, recycling, etc.) and highly efficient use of CCA. EPA's objectives
are to develop a complete, unbiased view of the CCA wood-treating industry, to estimate the
amount of hazardous wastes that a well-maintained CCA treatment plant would generate,
and to examine the possibility of using CCA more efficiently. The information collected will
be used to develop a pollution prevention guide that will assist wood treaters in identifying
ways to prevent pollution and reduce wastes. The guide will provide options for improving
the efficiency of existing operations and, when feasible, implementing newer pollution
prevention technologies.
This document reports the results of the assessments. The two CCA plants
assessed were identified and recommended by the American Wood Preservers' Institute
(AWPI). Madison Wood Preservers, Inc. (MW) is located in Madison, Virginia. Universal
Forest Products, Inc. Ranson Plant (RP) is located in Ranson, West Virginia. Both plants are
privately owned, large-sized wood treaters that use only CCA as wood preservative. The
plant visits were conducted in Madison on February 4-5, 1993, and in Ranson on
February 8-9, 1993.
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SECTION 2
ASSESSMENT METHODOLOGY
The procedures outlined in the assessment phase of EPA's Waste Minimization
Opportunity Assessment Manual (U.S. EPA, 1988) were used as a guide for the CCA plant
assessments. The original assessment phase involves six steps:
1. Collect process and facility data.
2. Prioritize and select assessment targets.
3. Select assessment team.
4. Review data and inspect site.
5. Generate options.
6. Screen and select options for further study.
However, a simplified approach was taken during the assessments at the two CCA plants.
The steps involving process and facility data collection, assessment targets selection, and
data evaluation (Steps 1, 2, and 3) were combined with the site inspection (Step 4). The
steps involving waste minimization (WM) options generation, screening, and selection
(Steps 5 and 6} were omitted because the purpose of this assessment project is not to
develop WM options.
Before the plant visits, letters were sent to the plant owner/General Manager,
briefly stating the purpose of the project, the goals of the plant visits, the assessment
approach, and the expected use of the assessment results. Upon arrival at the plants, the
site visitors reviewed and discussed these subjects with the plant management. During the
discussions and plant tours, emphasis was placed on the sources of wood-preserving
contamination, treatment processes and facilities, and WM practices. Typical questions
asked to facilitate the information gathering effort are listed below:
What wastestreams are generated from the plant? What quantity of
wastes do these contain?
Which processes or operations generate these wastestreams?
Which wastes are classified as hazardous and which are not?
What input materials are used that generate the wastestreams of a
particular process or plant area?
How much of a specific input material enters each wastestream?
How much of a raw material can be accounted for through fugitive
losses?
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How efficient is each waste-generating process?
Are unnecessary wastes generated by mixing otherwise
recyclable hazardous wastes with other process wastes?
What types of housekeeping practices are used to limit the quantity of
wastes generated?
What types of process controls are used to improve process efficiency?
Notes were taken during the discussions and plant tours. Additional information
gathered fell into several categories:
Design documents
Raw material and production information
Environmental information
Economic information.
Design documents included process flow diagrams, operating manuals and process descrip-
tions, equipment data sheets, and equipment layouts. The raw material and production
information included material safety data sheets, product and raw material inventory records,
operator data logs, operating procedures, and production schedules. The environmental
information included hazardous waste manifests, emission inventories, hazardous waste
reports, waste analyses, environmental audit reports, and permits and/or permit applications.
The economic information included disposal costs, product and raw material costs, and
operating and maintenance costs.
The WM assessment worksheets 4 to 10 in the Waste Minimization Opportunity
Assessment Manual were used to facilitate the assessment process. The title and purpose of
these worksheets are summarized in Table 1. The worksheets are presented in Appendix A.
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TABLE 1. LIST OF WASTE MINIMIZATION ASSESSMENT WORKSHEETS
Number
Title
Purpose
8
10
Site Description
Personnel
Process Information
Input Materials Summary
Products Summary
Individual Waste Stream
Characterization
Waste Stream Summary
Lists background information about the facility,
including location, products, and operations.
Records information about the personnel who
work in the area to be assessed.
Provides a checklist of useful process information
to look for before starting the assessment.
Records input material information for a specific
production or process area. This includes name,
supplier, hazardous component or properties, cost,
delivery and shelf-life information, and possible
substitutes.
Identifies hazardous components, production rate,
revenues, and other information about products.
Records source, hazard, generation rate, disposal
cost, and method of treatment or disposal for each
wastestream.
Summarizes all of the information collected for
each wastestream. This sheet is also used to
prioritize wastestreams to assess.
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SECTION 3
DESCRIPTION OF THE PLANTS
This section describes the wood-treating facilities, wood-treating processes, and
wood-drying and storage facilities of the two CCA treatment plants visited on
February 4-5, and February 8-9, 1993.
MADISON WOOD PRESERVERS, INC.
Madison Wood Preservers, Inc. (MW) was founded in 1959 and has been in
continuous operation at the same location ever since. It is located on a 75-acre lot in a rural
area in Madison, Virginia (on U.S. Route 29, about 25 miles north of Charlottesville, Virginia).
The company was one of the original Wolman licensees with Koppers Co. (now Hickson),
which is one of the three major CCA chemical and equipment suppliers in the USA. The
original thrust of MW's business was supplying pressure-treated agricultural fencing. Its main
products now include CCA-treated lumber, timber, and other related forest products. The
company hires 65 employees. Its 1992 production volume was 50 million board feet; the
annual production projected for 1993 is 60 million board feet. Its around-the-clock capacity
is 365 million board feet per year.
Old Treatment Plant
Madison Wood Preservers' original treatment plant consisted of three pressure-
treating cylinders. The first cylinder (5 ft x 32 ft), installed in 1959, could treat 8,000 to
10,000 board feet/charge/day. The second and the third cylinders (6 ft x 50 ft) were added
in 1962 and 1977, respectively, to keep up with the demand for treated fencing and other
CCA-treated wood products. In 1980, the two older cylinders were lengthened and installed
with automated controls in a new building.
In 1992, one of these cylinders was relocated into MW's new treatment plant.
Other equipment in the old treatment plant is being dismantled for disposal or resale.
New Treatment Plant
In 1991, MW invested 5.5 million dollars to build a
company decided not to upgrade its old facilities because the
and were poorly designed for efficient material handling, and
regulations such as the new drip pad requirements in 40 CFR
stormwater runoff regulations are pending. Compliance with
would cost approximately 20% of the cost of building a new
is housed in a single building that covers an area of 41/3 acres
new treatment plant. The
old facilities were spread out
because more stringent
Part 265, Subpart W, and the
these regulations by retrofitting
treatment plant. The new plant
. The plant is the largest
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treating facility of its type in the USA. Figure 1 shows the plant's side view, and Figure 2
shows the plant layout.
The design and engineering of the new plant was done primarily by Hickson
Corporation in Atlanta, which provided services in areas such as electrical, mechanical,
chemical, and environmental engineering, and in industrial hygiene. The overall design for the
new plant incorporates the basic concept of "containment, capturing, recycling, and
prevention." The company has emphasized "prevention" according to the belief that "it is
easier to prevent than to correct." The plant thus incorporates many safety features that are
not expected to become law for at least several more years. As a result, the Virginia Water
Pollution Control Board has rated this facility as a pollution abatement facility.
Overview of Wood-Treating Operations
Figure 3 shows a flow diagram of the wood-treating operations at MW. Truckloads
of lumber arrive at the receiving area located in the open yard just outside of the northeast
corner of the treatment plant. There the shipment loads are inspected to determine if they
meet the required specifications and are undamaged. MW requires that all loads of lumber be
covered by tarpaulins during transit to reduce the amount of road dust and grime reaching the
lumber. The company has stopped buying lumber from sawmills that do not keep their
lumber neat and clean. If needed, the lumber may be power-washed and debris removed
before it is forklifted into the untreated-wood storage area in the treatment plant.
Before treatment, lumber is rebanded with plastic strapping into appropriate size
units. Wood crosspieces (2-in x 2-in) are used to avoid lumber damage during forklifting (see
Figure 4). The lumber units thus prepared are end-squeezed to ensure neat packing (see
Figure 5), and individual pieces of, lumber in each lumber unit are tagged. The tagged lumber
units are then forklifted to the lumber-handling system where the untreated lumber units are
placed parallel to the treating cylinder to form a line of < 100 linear ft. The entire length of
Figure 1. A side view of Madison Wood Preservers' new treatment plant.
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8
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Figure 4. Lumber banding with plastic straps and wood crosspieces.
Figure 5. Lumber end-squeezing.
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the untreated lumber units is moved by an automatic chain conveying system. The lumber
handling system is divided into three areas designated by the terms "white chain," "center-
line chain," and "green chain." The untreated lumber stays in the white chain area until
treatment.
A treatment cycle begins with moving the untreated lumber units to the center-line
chain, loading them into the pressure-treating cylinder, unloading the freshly treated lumber
units back to the center-line chain, and moving them to the green chain. The freshly treated
lumber units then remain on the green chain for at least 1 to 2 days before being forklifted to
drying sheds or to the storage areas in the treatment plant.
Treatment Plant Building
The building shell of the new treatment plant contains 33 trailer loads of steel that
provide a snow load of 30 Ib and a wind load of 80 mph (with no tributary load reductions
allowed). The eight roof fans provide a complete air exchange every 15 min. The concrete
floor that covers the entire plant area contains more than 5,000 yd3 of reinforced concrete
with a minimum thickness of 8 inches.
Lumber Handling System
The lumber handling system (LHS) was designed and manufactured by Automated
Lumber Handling, Inc. of Lenoir, North Carolina. The LHS replaces the conventional
forklift/rail-tram system with an automatic chain conveying system to load and unload lumber
before and after pressure treatment (see Figure 6 for a system layout). As the LHS moves
untreated and freshly treated lumber units with the chains, it also intercepts chemical drips
from the cylinder doors and the freshly treated wood with a 100 ft x 104 ft elevated drip pan
{see Figure 7). Thus, the LHS eliminates the need for both human and equipment traffic on
the drip pad and removes any chance of tracking chemicals off the drip pad.
The drip pan is elevated 4 ft off a recessed floor that covers the areas beneath the
drip pan and the three treating cylinders. The 8-in-thick concrete floor is coated with an
impermeable Plasite surface coating. The recessed areas form the secondary containment,
which is designed to retain accidental chemical spills from the drip pan, the treating cylinders,
and the primary containment in the tank farm (see page 13). The drip pan and the Plasite-
coated concrete floor provide two levels of protection against chemical spills and
contamination.
The three related assemblies of the automatic chain conveying system move the
lumber sideways through the treatment cycle. The white chain assembly moves untreated
lumber from the white chain to the center-line chain. The center-line chain assembly
loads/unloads lumber both to and from the treating cylinders. The green chain assembly
moves freshly treated lumber from the center-line chain to the green chain, where the freshly
treated lumber is placed for at least 1 to 2 days before being forklifted to storage or to
drying. The chemicals intercepted by the drip pan are hosed down 3 to 4 times a year.
Pressure-Treating Facilities
The new treating facilities consist of three parallel treatment cylinders (two 7 ft x
100 ft [24,000 gal], see Figure 8, and one 6 ft x 50 ft [10,000 gal]). Each has one vacuum
compressor pump, one high-pressure pump, and one strip pump. The two 7 ft x 100 ft cylin-
ders {manufactured by Addison, Inc., Addison, Alabama) are supported on concrete piers on
the recessed floor. Each of these cylinders treats 25,000 board feet of lumber or timber/
charge. On average, 4 to 5 charges may be treated per 8-hour shift. The 6 ft x 50 ft cylinder
treats only 10,000 board feet/charge and is used primarily for posts and specialty lumber.
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Figure 7. Automatic chain conveying system and drip pan above
the recessed floor for lumber moving, drippage
intercepting, and spill retaining, respectively.
Each cylinder is equipped with a series of powered rollers driven by three
20-horsepower (hp) motors mounted on the outside of the cylinders. The powered rollers
along with the center-line chain conveyors transfer lumber into and out of the cylinders
without using forklifts and rail-tram. The treating cylinders are tilted slightly towards the
working tanks and the tank farm so that excessive drippage does not occur when the cylinder
doors are opened.
The treating cylinders are equipped with the largest pumps (e.g., up to 150 hp) in
the wood-treating industry. These pumps are used to perform rapid cycle treatment, which
produces lightweight products with less dripping. The rapid cycle treatment is achieved by
using 12-in fill lines to move the CCA work solution at rates up to 8,000 gpm to the 7 ft x
100 ft cylinders. A similar treatment can be performed on the 6 ft x 50 ft cylinder using a
6-in fill line. The CCA chemicals can be impregnated into wood cells in less than 4 min,
allowing more time for fixation with wood cells. Further, the large pressure pumps can reach
175 psi in the cylinder in less than 3 min. The large vacuum pumps pull vacuum up to 27 in
Hg in the cylinder within 1 to 2 min. The strip pumps continuously pull chemicals back to the
work tanks.
12
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Figure 8. Two 7' x 100' treating cylinders on concrete piers above the
recessed floor.
Tank Farm
The tank farm is housed in a heated building adjacent to the cylinder area of the
treatment plant. The 120 ft x 50 ft building is completely surrounded by 18-in-high,
8.5-in-wide concrete retaining walls. The surrounding area forms the primary containment
which can retain up to 40,000 gal of liquid, equivalent to the volume of one large CCA work
tank. The retaining wall separating the tank farm and the neighboring treating cylinder area
has a 6-in-deep, 36-ft-long cutout that functions as a weir to allow liquid to overflow from
the primary containment to the secondary containment during major chemical spills (such as
multiple tank ruptures). The primary and the secondary containments have a total capacity
equivalent to the total volume of liquid stored in the tank farm. The concrete floor of the
primary containment has an impermeable epoxy surface coating and an 80-mil underground
liner. The lined area is divided into six sections; each is sloped to a sump where a leakage
detection system is installed.
The tank farm is composed of four 41,858-gal tanks (each 18 ft diameter and 22 ft
high), four 18,603-gal tanks (each 12 ft diameter and 22 ft high), and one 12,914-gal tank
(10 ft diameter and 22 ft high) (see Figure 9 for a layout). The four 41,858-gal tanks are
painted light green and are CCA work tanks for the two larger cylinders (i.e., two for each).
The four 18,603-gal tanks are also painted light green: two serve as work tanks for the
smaller cylinder, one holds effluent (or makeup water), and one is empty. The 12,914-gal
tank is painted dark green and holds CCA concentrate. This tank is raised off the concrete
floor and has a cone-shaped bottom. The tip and the side of the cone are 29 in and 45 in off
the floor, respectively. The elevated tank and the cone-shaped bottom facilitate inspection
and allow visual reference in case of a leak (see Figure 10). The 12-ft-wide, 14-ft-talI
doorway and the 14 ft x 10 ft ramp located at the southwest corner of the tank farm building
13
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Figure 10. Elevated CCA concentrate tank with cone-shaped
bottom.
serve as a passage for chemical tankers to unload CCA concentrate inside the tank farm.
The unloading point has a quick hookup design to prevent release of chemical spills.
Chemical mixing is performed with a computer-controlled enclosed system (see
Figure 11) in the tank farm. A wax emulsion and a mold inhibitor are metered into the CCA
work solution in different proportions, depending on the product and customer requirements.
The treating solution contains 1.5-2.0% CCA active ingredients and 10-15 ppm mold
inhibitor. The use of this automatic mixing system eliminates the need for workers to enter
the tank farm on a regular basis. Moreover, the tank farm has automatic temperature,
pressure, and safety switches that allow remote monitoring and control.
All chemicals used by MW are supplied by Osmose Corporation (Griffin, Georgia).
In 1992, the annual consumption of 50% CCA concentrate was 1,057,620 oxide pounds,
equivalent to about 46 tanker loads. The annual consumption of the wax emulsion was
322,500 Ibs, or 120 totes (8 trailer loads of totes at 15 to 16 totes/load). The 1992
consumption of mold inhibitor was 3,850 Ibs, or 14 drums (275 Ibs/drum). Because the wax
15
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Figure 11. Enclosed chemical mixing system with the large wax tote on
the metal stand, bag filter cartridge by the metal stand, and
mold inhibitor drums at the far end.
emulsion causes the treated lumber to drip more than that treated without it, MW has
eliminated the use of wax emulsion for 2 in x 8 in and wider lumber.
Chemical drips and washdown water collected from the drip pan, and water used to
clean, rinse, or wash chemical containers, parts, or equipment, are combined and filtered
through 10-//m polyester bag filters before being returned to the effluent (or makeup water)
tank for reuse. The recycled solution is metered and the volume recorded so that any
problems may be monitored, controlled, and/or eliminated. The filter bags are cleaned daily;
the solids removed from the filter bags are disposed of as hazardous wastes. MW estimates
two drums of hazardous wastes per year from this source.
The tank farm acts as a single point source for all venting from the cylinders and
the chemical tanks. There are no vents from the tank farm building to the outside
atmosphere. Because all cylinder air emissions are returned to the work tanks, any mists or
droplets would be captured and contained in the wqrk tanks. Therefore, no additional air
pollution control devices are needed in the tank farm. Virginia Department of Air Pollution
Control (DAPC) requires CCA treatment plants to obtain emission permits if arsenic emissions
exceed 0.013 Ib/hr. MW would emit 0.0139 Ib arsenic/yr (including 0.00832 Ib/yr from both
7 ft x 100 ft cylinders, 0.00143 Ib/yr from 6 ft x 50 ft cylinder, and 0.00413 Ib/yr from all
work tanks) if the plant operates around the clock for 365 days a year. Therefore, the plant
is exempt from DAPC permitting requirements.
Process Control
The computerized pressure-treating process is controlled and monitored by Hickson
treatment control panels in a control room located in the northwest corner of the office
16
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building. The control room has a direct access to the tank farm and to the treatment plant.
A treatment cycle includes the steps to:
Apply initial vacuum
Fill the cylinder under vacuum with CCA work solution
Exert high pressure
Slowly release pressure
Blow back CCA work solution to the CCA work tank
Apply final vacuum
Strip residual CCA work solution to the CCA work tank.
The time required to complete a treatment cycle varies with wood density, dimensions,
retention requirements, and treatment methods. The modified full-cell method is used for
most treatments; the semi-full-cell method is used for denser materials and timber (including
4 in x 4 in, 6 in x 6 in, and 8 in x 8 in dimensions). A typical process flow diagram is
presented in Figure 12; the related treatment conditions are listed in Table 2.
The treatment conditions are controlled by a computer set up to achieve both
proper chemical retention and minimum drippage. Inputs to the computer include location of
sawmills; density, grades, sizes, and past treatability of the wood product; treatment records
of previous runs; etc. Among the most important treatment conditions are pressure levels
and durations during the high-pressure treatment, time for pressure release, and initial and
final vacuum. High pressure at 150 to 165 psi over a period of 5 to 8 min normally is applied
to the wood being treated. It is important not to overtreat because overpressuring could
collapse wood cells, causing excessive dripping, especially if a refusal point is reached. After
the high-pressure treatment, pressure is slowly released to atmospheric pressure in 8 to
15 min. The vacuum pumps pull vacuum up to 27 in Hg within 1 to 2 min. The final
vacuum is applied over a period of up to 2 hrs. All of these conditions serve to reduce the
amount of dripping from the treated products.
The treated products are analyzed for chemical retention using an X-ray
fluorescence analyzer. The analytical results report total and individual oxide retention (as
CrO3, CuO, and As205) in Ib/ft3.
Wood Drying and Storage
The freshly treated lumber remains on the green chain for 1 to 2 days to allow
drips to stop. The lumber is then transferred to the storage areas or a drying shed for further
drying. About 70% of the plant production is kept in the inside storage areas in the
treatment plant. The other 30% is dried after treatment to 19% moisture content (M.C.)
which is done in the drying shed. Up to 0.5 million board feet of outdoor wood is placed in
orderly stacks in the shed (see Figure 13), through which air circulates. The air is drawn by
72 electrical fans installed on one side of the shed. Under favorable weather conditions
(about 65ฐF and 45% relative humidity [RH]), it takes from 2 to 2.5 weeks for the wood to
dry down to the required maximum moisture content (about 19%). Currently, the shed's
capacity is enough to hold 0.75 million board feet. About 25% of the lumber is dried in
stacks on the open yard. The wood stacks dried in the open yard are covered with paper to
avoid, .direct exposure to rainfall.
17
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TABLE 2. TREATMENT CONDITIONS OF TYPICAL PRESSURE-TREATING PROCESSES
Process Conditions
Pressure-Treating Cycle
Modified Full-Cell Method
Semi-Full-Cell Method
Initial Vacuum
Filling Cylinder via Vacuum
Applying Pressure
Slow-Pressure Release
Blowing Back
Final Vacuum
Final Stripping
10-14 in Hg for 10 min
4 min
150-165 psi for 5-8 min
8-15 min
10 psi for 3 min
27 in Hg for 60-120 min
0-30 sec
27 in Hg for 12 min
4 min
150-165 psi for 5-8 min
N/A
10 psi for 3 min
27 in Hg for 0-30 min
0-30 sec
N/A - not applicable
Figure 13. The drying shed.
19
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UNIVERSAL FOREST PRODUCTS, INC.,
RANSON TREATMENT FACILITY
Universal Forest Products, Inc. owns 10 wood-treating facilities and 27 forest
products manufacturing facilities. The company was founded in 1955. The company does
business across the country. The Ranson Plant (RP) was built in 1988 and has been in busi-
ness continuously since then. The plant's 15-acre lot is located in a rural area in Ranson, West
Virginia, which is about 80 miles northwest of Washington, DC. The RP lot layout is presented
in Figure 14, which shows the relative location of the shipping and receiving areas, sawmills,
wood stacking room, treatment plant, drying sheds, wood storage yard, and offices.
The plant operates in two shifts and treats about 55 million board feet per year of
Southern Yellow Pine (SYP) boards, decking, dimensional, lumber, and timber. The plant's
full capacity is 70 million board feet. The plant employs 35 and 60 employees during the
winter and summer seasons, respectively.
Overview of Wood-Treating Operations
Figure 15 presents a flow diagram of the RP wood-treating operations. Untreated
lumber arriving in bulk units by railroad cars is tagged and stored in the unpaved open yard.
The lumber is then restacked by a stacker (see Figure 16), banded with plastic strap (see
Figure 17), and left in the open yard until moved for treatment. When the lumber units are
moved for treatment, they are forklifted to the conditioning building and placed parallel to the
rail/trench (see Figure 18). The units are then loaded onto trams by forklifts, fastened with
heavy-duty belts, and pulled into the treating cylinder by a motor cable. After treatment, the
freshly treated lumber units are pulled out of the cylinder, forklifted to the conditioning area
{or drip pad) and allowed to drip on the conditioning area for 1 to 3 days (average 30 hrs).
The treated wood stacks are then transferred by forklift to one of the three drying sheds or to
the open yard.
Pressure Treatment Plant
The treatment plant is composed of a cylinder room, a conditioning building, and a
process control room. The cylinder room is a long, narrow structure annexed to the east side
of the main conditioning building. The cylinder room contains the pressure-treating facility,
including one 6.5 ft x 82 ft (or 20,000-gal) treating cylinder, one rectangular combination
tank (40 ft x 10 ft x 10 ft), one primary work tank (40 ft x 10 ft x 6.9 ft), pumps, pipes, and
an underground pit. The conditioning building has a rail/trench system which divides the
conditioning building into two separate areas: the lumber loading area and the conditioning
area (or drip pad). The entire complex (cylinder room and conditioning building) is underlined
with a continuous 30 mil plastic liner. The treatment plant was designed by Rentokil, a
company acquired by Chemical Specialties, Inc. (CSI) in Charlotte, North Carolina. The
treatment plant layout is shown in Figure 19.
Cylinder Room
The treating cylinder and combination tank sit side-by-side in the cylinder room.
The cylinder lies on four steel supports with a slight tilt towards the opposite direction of the
cylinder door. The combination tank sits on a concrete floor. In between the cylinder and
the combination tank is a narrow walkway. The cylinder and the combination tank are
surrounded by retaining walls on the north, south, and east sides. The opening on the west
side connects the cylinder room to the conditioning building. Directly underneath the cylinder
20
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Treated Lumber
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Sawmills
X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X -X-X-X-X-X XXXXXXXXXXXX
Open Yard
Lumber Storage
Railroad
x x x x Fence
Figure 14. Ranson plant layout (not scaled).
21
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! Operations Performed '
' In the Treatment Plant I
I
, _ J
Figure 15. Flow diagram of wood-treating operations at Ranson plant.
Figure 16. Lumber restacking by a stacker.
22
-------
Figure 17. Lumber banding with plastic strap.
is a wooden deck separating the ground level and the underground pits and primary work
tank. The cylinder room is heated to normal room temperature.
The combination tank is made of 0.25-in steel. The tank is subdivided into four
compartments of different sizes: the 4,500-gal compartment contains 60% CCA concentrate;
the 11,400-gal compartment contains water; the 16,000-gaI compartment is a secondary
storage for the CCA work solution; and the 120-gal compartment is a CCA metering tank.
The primary work tank sits in the long section of an L-shaped underground pit (see Figure 20)
underneath the cylinder and the wooden deck. The tank holds up to 22,000 gal CCA work
solution.
A mold inhibitor (MOLD-EXฎ H.E.14 Wood Mildewcide) is metered into the CCA work
solution in the cylinder room (see Figure 21). A typical CCA work solution contains 1.65%
CCA active ingredients and 10 ppm mold inhibitor. Occasionally, a wax emulsion (Ultra
Wood Concentrate Water Repellent Additive) is added to the CCA work solution to treat
products that must be water repellent. The solution is prepared by sequentially adding the
wax emulsion, CCA concentrate, and water into the primary work tank and agitating the
mixture by opening the primary mixing valve and turning the pressure pump from automatic
to manual for 2 to 3 min.
All chemicals are supplied by CSI. In 1992, the annual consumption of the 60%
CCA Type-C Concentrate was 90,000 gal (or 840,600 oxide pounds), equivalent to 37
tanker loads. The mold inhibitor consumption was 500 gal, or 15 drums of 35-gal capacity.
The wax consumption was 5,000 gal, or 18 totes.
The front (door) pit underneath the cylinder door consists of one 24 ft x 4 ft
x 6.9 ft concrete pit with one 8 ft x 3 ft x 3 ft steel liner and one 4 ft x 2 ft x 2 ft steel
spillover extension. The concrete pit is coated with a sealer and lined with a layer of plastic
liner. The 0.25-in steel liner sits in the front (door) pit and is positioned directly under the
23
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Figure 18. Rail/trench system, lumber loading area (left), and chemical-
covered drip pad or conditioning area (right).
cylinder door. The steel liner with four splash guards can hold up to 500 gal of liquid. The
overflow from the steel liner is spilled over into the 100-gal spillover extension. Three pumps
installed separately at the spillover extension, the steel liner, and the front pit transfer the
liquid to the primary work tank for reuse. Below the cylinder is the longer section of the large
L-shaped concrete pit measuring approximately 76 ft x 12 ft x 6.9 ft (long section of the L)
and 10 ft x 24 ft x 6.9 ft (short section of the L) (see Figure 20). As mentioned above, the
primary work tank sits in the long section of the L.
A two-stage automatic alarm system is installed to monitor and alert any chemical
spills in the underground pits. If liquid threatens to overflow the steel liner, a red light flashes
in the control room to warn plant operators. If liquid spills over to the front (door) or main
(L-shaped) pit areas, an automatic telephone calling sequence is triggered. Two levels of
plant management are called at home to alert them to the spills. A third call is made to a
24-hour answering service, which initiates calls in sequence according to a list of 12
numbers, until someone responds to the overflow.
24
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Ramp
Overhead Door
Overhead Door
Overhead Door
Overhead
Door
Conditioning Area
(or Drip Pad)
Rail/
Trench
System
Chemical
Storage
Hazardous Waste
Drying/Storage
Mold Inhibitor
Mixing Area
Pressure
Treating
Cylinder
Lumber
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Cylinder
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Combination
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Break Area
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Figure 19. Treatment plant layout at Ranson (not scaled).
25
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Figure 21. Floor slab separating treating cylinder and underground
pit and underground CCA primary tank (not shown).
Mold inhibitor in drums is fed at the cylinder side.
Conditioning Building
The conditioning building is used primarily for lumber loading, lumber unloading,
drippage interception, and treated lumber conditioning. The building is divided by a 1-ft wide,
90-ft long, and 4- to 12-in-deep concrete trench that slopes towards the cylinder room (see
Figure 18). Two rails at 34 in apart are laid on top of the trench. Trams loaded with
untreated or treated lumber are pulled onto or off the cylinder by a motor cable. The motor
cable box is located opposite the cylinder door. The entire building is covered with a
concrete floor. The area north of the trench is the lumber loading area, and the area south is
the conditioning area (or drip pad). The concrete floor of the lumber loading area is 8 in
higher than that of the conditioning area.
Operators wearing rubber boots walk around the freshly treated lumber units after
treatment to unfasten the belts from the treated units and transfer the treated units from the
trams to the conditioning area using forklifts. To facilitate dripping, the lumber units are
placed with a slight angle on the drip pad (see Figure 22). The treated lumber units remain
27
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Figure 22. Freshly treated lumber units on drip pad.
on the conditioning area pad for 1 to 3 days before being forklifted to the drying sheds or to
the open yard for further drying or storage.
The conditioning area is hosed down daily. Chemicals and washdown water are
directed towards the trench and filtered through a wire screen at the end of the trench. The
filtered solution flows into the underground steel liner. Wood chips, debris, and sludge
intercepted in the trench (see Figure 23) are shoveled weekly to a two-screen setup for air
drying (see Figure 24). The air-dried solids collected on the top screen are disposed of as
nonhazardous waste in a dumpster; the finer solids collected on the bottom screen are
disposed of as hazardous waste.
The conditioning building is insulated and heated in the winter by a gas-fired make-
up air heater/blower. In summer, the blower can be used to circulate air, augmented by
electric fans installed on the side walls. The vents from the cylinders, the combination tank,
and the primary work tank are all directed to the conditioning building. Universal Forest
Products monitors the arsenic emission annually. The arsenic concentrations in air have been
consistently below 5 //g/m3.
Process Control Room
The process control room located at the northwest corner of the cylinder room has
immediate access to the cylinder room and conditioning building. The control room has a
simple setup, including a set of visible volume meters, a process control panel, and a small
laboratory bench. The modified full-cell method is used for most treatment. Typically, the
treatment begins with chemical flooding under vacuum. Two 12-in pipes are used to transfer
enough CCA work solution to flood the cylinder in 3 min. A pressure of up to 175 psi is then
exerted on the lumber for 4 to 8 min (until correct absorption of CCA liquid has occurred).
28
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Figure 23. Sludge, wood chips, and debris in trench.
Figure 24. Two-screen setup for solid waste air drying.
29
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An initial drain of chemical follows and lasts for 3 min. A final vacuum of 28 in Hg is applied
for 20 to 30 min. A final drain lasts for 3 to 5 min.
The treated products are analyzed for chemical retention using an X-ray fluores-
cence analyzer. The analysis reports total and individual oxide retention (as Cr03/ CuO, and
As2O6) in Ib/ft3.
30
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SECTION 4
WASTE MINIMIZATION PRACTICES
Both Madison Wood Preservers, Inc. and Universal Forest Products Hanson Plant
have adapted a number of waste minimization (WM) practices that have greatly improved the
plants' ability to prevent pollution and reduce wastes. The WM practices have been reflected
in several areas, including facility designs, process controls, and management practices. This
section describes these WM practices and explains how they affect pollution prevention and
waste reduction.
FACILITY DESIGNS
The treatment plants have incorporated many pollution prevention designs,
including enclosed treatment buildings, covered drip pads, a drip pan, an automatic lumber
handling system, power rollers, a tank farm, spill containments, and air ventilation systems.
Enclosed Treatment Buildings
Both treatment plants are housed in enclosed structures, which provide shelters for
chemical storage and mixing, lumber handling and treating, process control, and/or lumber
conditioning and drying. The enclosed treatment buildings protect chemicals, treating
facilities, freshly treated wood, and drip pads from direct exposure to the ambient weather
conditions, thereby reducing the possibility of chemical contamination to the environment.
Covered Drip Pads and Drip Pan
Both treatment plants have a concrete floor covering the entire plant. The MW
plant has an elevated metal drip pan. The concrete floor has an impermeable Plasite surface
coating. The drip pan intercepts chemicals dripping from the cylinder doors and freshly
treated lumber; therefore, no direct contact between the chemicals and the concrete floor
would ever occur unless there is a major chemical spill. The recessed floor covers the areas
under both the drip pan and the three treating cylinders. The recessed floor can function as a
chemical spill containment to retain spilled liquid that overflows from the primary containment
in the tank farm.
The unique design of the drip pan and the lumber-conveying system eliminates the
need for human and equipment traffic during lumber handling and treating. Because
chemicals are not tracked from the drip pan and the drip pad, hazardous wastes generated in
the treatment plant are significantly reduced.
The chemicals intercepted by the drip pan are hosed down 3 to 4 times a year. The
solution is filtered through a 10-/;m filter bag before being recycled as makeup water. There-
fore, no sludge accumulation would be expected in the treating cylinders and CCA work tanks.
31
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In contrast, the lumber-handling operations at RP require both people and equipment
operating on the conditioning area (or drip pad) where a significant amount of chemicals
accumulate (see Figure 18). The operations involve transferring freshly treated lumber units
from trams to the conditioning area by forklifts. The tires of the dedicated forklifts may be
soaked in chemical solutions, but the vehicle is confined to the conditioning area to avoid
tracking of chemicals to the surrounding areas. Operators wearing rubber boots must walk
on chemicals over the areas by the cylinder door, the trench, and the drip pad. As a result,
chemicals can often be tracked inadvertently from the drip pad to the surrounding areas, such
as the lumber-loading area, process control room, and cylinder room. It is also possible to
further track chemicals into the break room (next to the cylinder room) and to the areas
outside of the treatment plant. Additional access to the break room is provided from the
outside yard to prevent tracking of chemicals to that location.
Automatic Lumber Handling System and Power Rollers
MW uses the automatic lumber handling system and power rollers for its lumber
loading and unloading operations. The automatic lumber handling system transfers lumber
units from the white chain to the center-line chain and to the green chain by chain conveyors.
The power rollers and the center-line chain transfer lumber units into and out of the treating
cylinders {see Figure 25). The treated lumber units remain on the green chain until dripping
ceases. This method of lumber handling abandons the conventional forklift and rail-tram
system, thereby eliminating any direct contact between people and chemicals and between
equipment and chemicals.
Figure 25. Cylinder door opened right after treatment. Treated lumber
will be removed from the cylinder by powered rollers and
lumber handling system (not shown).
32
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RP uses the conventional forklift and rail-tram system for lumber handling.
Operators hose down daily the conditioning area, the trench, and the areas surrounding the
cylinder door. The sludge, debris, and wood chips intercepted in the trench are shoveled
weekly and air-dried on a two-screen setup before being disposed of.
Tank Farm and Spill Containments
MW places all of its chemical tankage in a heated building, or tank farm. The tank
farm incorporates several effective pollution prevention designs, including the primary spill
containment, elevated CCA concentrate tank, CCA concentrate inside unloading point,
enclosed chemical mixing system, and remote monitoring and control capabilities.
The primary containment in the tank farm is capable of containing chemical spills
equivalent to the volume of a large CCA work tank. Overflow from the primary containment
can be spilled over to the secondary containment. The total capacity of the primary and
secondary containments is equivalent to the total volume of the liquid stored in the tank
farm, thus eliminating any possibility of chemical spills over the uncontrolled areas. The
concrete floor in the tank farm is coated with a layer of impermeable coating and lined with
an 80-mil liner. The lined area is monitored by six detection systems for chemical leakage.
The CCA concentrate tank is elevated off the concrete floor with a cone-shaped
bottom. The elevated tank and cone-shaped bottom facilitate inspection and allow visual
reference in case of a leak. The CCA concentrate can be unloaded from a chemical tanker in
the tank farm through an unloading point right next to the concentrate tank, thus preventing
any release of chemical spills to the uncontrolled areas. All CCA work tanks sit 1 in off the
concrete floor on metal strips to aid in detection of chemical leaks.
Chemical mixing is carried out in a computer-controlled enclosed system. In
addition, the tank farm has automatic temperature, pressure, and safety switches for remote
monitoring and control. These designs eliminate the need for workers to enter the tank farm
on a regular basis, thus reducing worker exposure to the chemicals.
The more conventional RP design does not include a separate building for its combi-
nation tank and the primary CCA work tank. However, the concrete pits are large enough
(about 60,000 gal capacity) to hold the maximum possible content of the combination tank
and primary work tank at one time (about 54,000 gal). In addition, the conditioning building
floor is designed as a secondary containment. In the event of a catastrophic failure of a
water line, this area can hold an additional 25,000 gal of liquid before overflow to the
uncontrolled areas could occur. If the spills are minor, the three pumps equipped to the
underground pit would transfer the liquid to the primary or secondary work tank. The
automatic alarm/telephoning system provides further protection against chemical buildup in
the pits.
The underground pits are covered with a wooden deck, and access to the pits is
restricted to three access positions with a fixed ladder. The rectangular combination tank
sitting on a concrete floor is surrounded by a retaining wall on one side and the process
control room on the other side. The primary work tank lies in the L-shaped underground pit
underneath the wooden deck. All of these areas are not readily seen from the treatment
plant level. Therefore, monitoring of chemical leaks would not be as easy as at MW.
However, RP does have a remote monitoring and control system in place.
Air Ventilation Systems
MW's treatment building has eight roof fans that provide a complete air exchange
every 15 min. The tank farm is used as a single point source for all venting from the
33
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cylinders and chemical tanks. Because the plant incorporates designs to minimize mist or
droplet emissions from the cylinders and work tanks, no additional air pollution control
devices are installed in the tank farm. The plant is exempt from DAPC permitting require-
ments because its arsenic emission is much lower than the regulated limit.
RP directs the vents from the cylinder, combination tank, and primary work tank to
the conditioning building. The conditioning building has air ventilation in the form of makeup
air through the heater/blower and fans on the outside walls.
PROCESS CONTROLS
The treatment processes at MW are carefully controlled to ensure proper chemical
retention and minimal dripping. Several process control methods are used and are
summarized as follows:
CCA oxides are used to enhance chemical fixation in wood.
The treatment processes are computer-controlled and monitored.
Lightweight products that drip less are produced via rapid cycle
treatment. The treatment is performed by feeding the treating
cylinders with CCA work solution at rates up to 8,000 gpm. The
industry's largest pumps and 12-in fill lines are used to facilitate this
process. CCA chemicals are pushed into wood cells in less than 4 min.
High pressure at 150 to 165 psi over a period of 5 to 8 min is applied
to the products treated. These treatment conditions eliminate
excessive dripping.
After the high-pressure treatment, a slow-pressure release follows
immediately and lasts for about 8 to 15 min. This also results in less
dripping.
Large vacuum pumps pull vacuum up to 27 in Hg within only 1 to
2 min. The final vacuum lasts up to a period of 2 hrs. This again
reduces the amount of dripping from the treated products.
The strip pumps continuously remove residual chemical solutions back
to the CCA work tank. This results in less dripping when opening the
cylinder doors.
The treating cylinders are slightly tilted toward the work tank. This,
again, allows less dripping when opening the cylinder doors.
The treated products are analyzed for chemical retention using an X-ray
fluorescence analyzer. Proper chemical retention is monitored to
ensure that treatment specifications are met and that overtreatment
does not occur.
34
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Research and development and operator's training programs are in
place for continuous improvement of treatment controls and skills.
HP's treatment conditions are similar to those used by MW, except that the
pressure release after the high-pressure treatment lasts for only 3 min and the final vacuum
lasts for only 20 to 30 min.
MANAGEMENT PRACTICES
~\
Several management practices adapted by both treatment plants have a significant
impact on pollution prevention and waste reduction. These practices include pretreatment
quality control, improved housekeeping, resource recovery and recycling, and operator
training.
Pretreatment Quality Control
Pretreatment quality control (PQC) is considered as one of MW's most important
methods to control waste volume. PQC begins even before the lumber reaches the plant.
For example, MW does not buy lumber from sawmills that do not keep lumber neat and
clean. MW also requires that all truckloads of lumber be tarped during transit to reduce the
amount of road dust and grime on the lumber. (MW estimates that having loads tarped
reduces hazardous wastes by 3 to 4 drums per year.) Upon arrival, shipment loads are
inspected by experienced inspectors to determine if they meet specifications and are without
unwanted damages. Off-grade or damaged lumber is returned to the shipping sawmills to
reduce waste volume. When necessary, the lumber will be power-washed and wood chips
and debris removed before it is forklifted into the treatment plant. The wood chips and debris
removed at the receiving area are disposed of as a nonhazardous waste.
PQC can significantly reduce the quantity of hazardous wastes by:
Reducing the quantity of sludge generated in the treating cylinder,
chemical work tanks, and/or bag filters.
Reducing the quantity of unsalable, out-of-spec, and/or damaged wood
products that would have to be disposed of as a hazardous waste.
Reducing the quantity of wood chips and debris that have been
inadvertently treated and, then, must be disposed of as a hazardous
waste.
Improved Housekeeping
Although the contribution of improved housekeeping to overall waste minimization
is difficult to quantify, simple housekeeping improvements may provide low- or no-cost
opportunities for reducing waste. MW considers housekeeping an integral part of its waste
minimization effort. The following housekeeping items are practiced at the MW plant:
35
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The concrete floor in the treatment building is vacuum-swept daily by a
riding power vac and manually swept in areas inaccessible to the
power vac.
High-grade rubber tires are used on forklifts. Currently MW is using
white solid rubber tires to reduce/eliminate tire marks on the concrete
floor (see Figure 26), which, in turn, reduces waste volume generated
in the plant.
MW inspects regularly the concentrate tank, work tanks, automatic
chemical mixing system, treating cylinders, drip pan, lumber-handling
system, and spill containments for chemical leaks and spills. These
areas are kept neat and clean. No chemicals, liquid puddles, or debris
are observed throughout these areas.
Figure 26. Tire marks on concrete floor as a result of forklift
operations.
36
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The unused mold inhibitor drums and wax totes are stacked neatly in
an open area in the tank farm.
A plastic container is hung under the concentrate unloading point to
intercept any chemical dripping.
Lumber, treated or untreated, is stacked neatly on the lumber-handling
system, in the treatment building (see Figure 27), or in the warehouse
storage yard to prevent the treated products from being damaged and
becoming unsalable. Any damaged products, wood chips, and debris
can be disposed of only as hazardous wastes.
All recycling bins, dumpsters, and containers are clearly marked and
placed at locations away from frequent traffic.
Wood crosspieces are used to separate wood units and to avoid
damage to wood by forklift (see Figure 4).
The treated lumber, after remaining on the lumber-handling system for
1 to 2 days, is removed for further drying either in the same treatment
building or in the drying shed (for outdoor products only). Because of
space shortage, about 25% of the outdoor products are placed in the
open yard for open-air drying. The lumber stacks in the open yard are
covered with paper to provide some protection from direct exposure to
rain. The paper covering reduces the amount of arsenic and chromium
being leached into stormwater runoff.
Figure 27. Neatly stacked lumber units in the treatment plant.
37
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Resource Recovery and Recycling
Both treatment plants are zero-discharge facilities, which recycle chemical drips,
spills, rinse water, and washdown water as a process water. MW also recycles most of its
waste materials and chemical containers. Some'examples are:
Metal banding used to fasten truckloads of lumber in transit. MW
makes 3.5C/lb by recycling the metal banding.
Plastic banding used to reband lumber before treatment. The plastic
banding is chopped into 2-in pieces and stored in large cardboard
containers before recycling (see Figure 28). MW makes 80/lb by
recycling the plastic banding.
Wood crosspieces separating wood units. MW has a rebate program
with the manufacturer.
Wax totes. MW returns empty totes to the manufacture (36 to 40
totes per trailer load) and receives $50/tote rebate on wax refill. The
damaged totes are rinsed for use as containers.
Mold inhibitor containers. These containers are rinsed for use as
regular storage containers.
Wood trim and strips from milling operations. The 1-in x 2-in strips are
used to produce lattice (see Figure 29).
Figure 28. Chopped plastic banding stored in large cardboard boxes for recycling.
38
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Figure 29. Stack of 1' x 2' lattice produced from wood trims and strips
from milling operations.
RP disposes of most of its chemical containers and wood trim and strips from its
milling operations.
Operator Training
MW and RP believe that to have a good operator training program in place is
another way to reduce waste. For example, a well-trained operator has better knowledge of
the treatment processes and his/her equipment, thus reducing the risks of producing
inadequately treated products or causing unneeded damage to the treated products. This
knowledge results in reduced waste volume.
39
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SECTION 5
HAZARDOUS WASTES GENERATED
This section describes the hazardous wastes generated by the two treatment
plants.
HAZARDOUS WASTES GENERATED
BY MADISON WOOD PRESERVERS
MW generated nine and six 55-gal drums of hazardous waste in 1991 and 1992,
respectively. Some of this hazardous waste was associated with shutting down the old plant
and moving over to the new plant. The projected waste volume to be generated by the new
treatment plant in 1993 is two to four drums, or one drum every 90 days. The waste is
composed of sludge removed from the filter bags, pump screens, and under the cylinder door
traps, dust, tags, and miscellaneous items. The disposal cost is about $200/drum. The
disposal is triggered by the U.S. EPA 90-day time guideline.
MW's EPA generator number is VAD003086360. Its SIC Code is 2491.
HAZARDOUS WASTES GENERATED BY
UNIVERSAL FOREST PRODUCTS RANSON PLANT
RP generates four drums/yr hazardous waste, or about one drum per 90 days. The
waste is collected from the bottom screen of the two-screen setup and is composed primarily
of sludge removed from the trench and from under the cylinder door traps. Wood chips,
debris, and other large items collected on the top screen of the two-screen setup typically are
disposed of as nonhazardous wastes. RP does, however, verify the toxicity characteristics of
these large items by the Toxicity Characteristics Leaching Procedure (TCLP).
HP's EPA generator number is WVD982364309. Its EPA profile number is RVF
BD101.
40
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SECTION 6
REFERENCES
Loebenstein, J. R. 1991. "Arsenic." Minerals Yearbook. U.S. Department of Interior,
Bureau of Mines, Washington, D.C.
Loebenstein, J. R. 1992. "Arsenic: Supply, Demand, and the Environment." Proc. Arsenic
& Mercury: Workshop on Removal, Recovery, Treatment, and Disposal. Alexandria, Virginia,
August, 17-20.
U.S. Environmental Protection Agency (U.S. EPA). 1988. Waste Minimization Opportunity
Assessment Manual. EPA/625/7-88/003, Hazardous Waste Engineering Research Laboratory,
Office of Research and Development, Cincinnati, Ohio.
41
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APPENDIX A
WASTE MINIMIZATION ASSESSMENT WORKSHEETS
42
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Brm.
Site
Date
Waste Minimization Assessment
Proj. No.
Prepared By
Checked By
Sheet J_ of J_ Page of
WORKSHEET
4
DESCRIPTION;
&EPA
Firm:
Plant:
Department:
Area;
Street Address;
City:
State/ZIP Code;
Telephone; (
Major Products;
SIC Codes:
EPA Generator Number
Major Unit or;
Product or:
Operations:
Facilities/Equipment Age:
43
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Cirm
-------
Firm
Site
Date
Waste Minimization Assessment
Proj. No.
Pซ
Ch
Sh
WORKSHEET
6
J^^NR0BBซCTION
jpared By
eckedBv
set 1 of 1 Pace of
vvEPA
Process Unit/Operation:
Operation Type: D Continuous
CH Discrete
CU Batch or Semi-Batch CH other
Document
Process Flow Diagram
Material/Energy Balance
Design
Operating
Flow/Amount Measurements
Stream
Analyses/ Assays
Stream
Process Description
Operating Manuals
Equipment List
Equipment Specifications
Piping & Instrument Diagrams
Plot and Elevation Plan(s)
Work Flow Diagrams
Hazardous Waste Manifests
Emission Inventories
Annual/Biennial Reports
Environmental Audit Reports
Permit/Permit Applications
Batch Sheet(s)
Materials Application Diagrams
Product Composition Sheets
Material Safety Data Sheets
Inventory Records
Operator Logs
Production Schedules
Status
Complete?
(Y/N)
Current?
(Y/N)
Last
Revision
Used In this
Report (Y/N)
Document
Number
Location
45
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Rim
Site
Oats
Waste Minimization Assessment
Prnj No.
Pre
Ch
Sh<
WORKSHEET
7
INPUT MATERIALS SUMMARY
'-.,,'''% .*""
pared By
acked By
aet 1 of 1 Page of
4* EPA
Attribute
Name/ID
Source/Supplier
Component/Attribute of Concern
Annual Consumption Rate
Overall
Component(s) of Concern
Purchase Price, $ per
Overall Annual Cost
Delivery Mode2
Shipping Container Size & Type8
Storage Mode4
Transfer Mode8
Empty Container Disposal/Management6
Shelf Life
Supplier Would
- accept expired material (Y/N)
accept shipping containers (Y/N)
- revise expiration date (Y/N)
Acceptable Substitute(s), if any
Alternate Suppliers)
Description1
Stream No.
Stream No.
Stream No.
1 stream numbers, If applicable, should correspond to those used on process flow diagrams.
2 e.g., pipeline, tank car, 100 bbl. tank truck, truck, etc.
3 e.g., 55 gal. drum, 100 Ib. paper bag, tank, etc.
4 e.g., outdoor, warehouse, underground, aboveground, etc.
* e.g., pump, forkllft, pneumatic transport, conveyor, etc.
* e.g., crush and landfill, clean and recycle, return to supplier, etc.
46
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Firm
Site
Data
Waste Minimization Assessment
Proj. No.
Prซ
CM
Sh
WORKSHEET
8
PRODUCTS SUMMARY
>pared By
ecked Bv
set 1 of 1 Paae of
^fc fnga^ jt
oEPA
Attribute
Name/ID
Component/Attribute of Concern
Annual Production Rate
Overall
Component(s) of Concern
Annual Revenues, $
Shipping Mode
Shipping Container Size & Type
Onslte Storage Mode
Containers Returnable (Y/N)
Shelf Life
Rework Possible (Y/N)
Customer Would
- relax specification (Y/N)
- accept larger containers (Y/N)
Description1
Stream No.
Stream No.
Stream No.
1 stream numbers, if applicable, should correspond to those used on process flow diagrams.
47
-------
Finn
Site
Hfltft
WORKSHEET
9a
Waste Minimization Assessment
Pro) No
Prepared Bv
Ch
Sh
'INDIVIDUAL WASTE ^TREAW"
b^^rCHABA^TEFllZAnOH .'.^;.
sckad By
set _2_ of 4 Page of
&EPA
1. Waste Stream Name/ID:.
Process Unit/Operation
Stream Number-
Waste Characteristics (attach additional sheets with composition data, as necessary.)
n
gas
CH liquid
I solid I I mixed phase
Density, Ib/cuft
Viscosity/Consistency
pH .Flash Point.
High Heating Value, Btu/lb.
; % Water
3. Waste Leaves Process as:
CU air emission CH waste water C3 solid waste EH hazardous waste
4. Occurrence
I I continuous
LJ discrete
discrete
discharge triggered by I_J chemical analysis
C_J other (describe)
Type: CU periodic length of period:
LJ sporadic (irregular occurrence)
LJ non-recurrent
5. Generation Rate
Annual
Maximum -
Average -
Frequency-
Batch Size-
Ibs per year
Ibs per
Ibs per
batches per
average
range
48
-------
Ran
Site
Date
WORKSHEET
9b
Waste Minimization Assessment
Proe. Unft/Op^r
Pro]. No.
Pi
Cl
SI
INDIVIDUAL WASTE STREAM
CHARACTERIZATION
repared By
tacked By
leet 2 of 4 Page of
&EPA
6. Waste Origins/Sources
Fill out this worksheet to Identify the origin of the waste. If the waste Is a mixture of waste
streams, fill out a sheet for each of the individual waste streams.
Is the waste mixed with other wastes? II Yes I I No
Describe how the waste is generated.
Example:
Formation and removal of an undesirable compound, removal of an uncon-
verted input material, depletion of a key component (e.g., drag-out), equip-
ment cleaning waste, obsolete input material, spoiled-batch and production
run, spill or leak cleanup, evaporative loss, breathing or venting losses, etc.
49
-------
Firm
Site
Date
Waste Minimization Assessment
Proo, Unit/Op**!"
Pmj No.
Prepared By
Checked By
Sheet 3 of 4 Page of
WORKSHEET
9c
INDIVIDUAL WASTE STREAM 43 PDA
. ; ^CHARACTERIZATION W C "M
(continued)
Waste Stream __
7. Management Method
Leaves site In
D bulk
CH roll off bins
I I 55 gal drums
LJ other (describe)
Disposal Frequency
Applicable Regulations1
Regulatory Classification2
Managed
Recycling
onsite
[~~] commercial TSDF
[U own TSDF
CH other (describe)
LJ direct use/re-use
f~1 energy recovery
D redistilled
LJ other (describe) -
offsite
reclaimed material returned to site?
I I Yes dl No I | used by others
residue yield
residue disposal/repository
Note1 list federal, state & local regulations, (e.g., RCRA, TSCA, etc.)
Note 2 list pertinent regulatory classification (e.g., RCRA - Listed K011 waste, etc.)
50
-------
Firm.
Site
Date
Waste Minimization Assessment
Proc. Unit/Oper.
Proj. No
Prepared By
Checked By
Sheet _4_ of _4_ Page
of
WORKSHEET
9d
INDIVIDUAL WASTE STREAM
CHARACTERIZATION
vvEPA
(contlniMd)
Waste Stream
7. Management Method (continued)
Treatment
CH biological
LJ oxidation/reduction,
I I incineration
I I pH adjustment
II precipitation
I solidification
EH other (describe)
residue disposal/repository
Final Disposition
Costs as of
landfill
pond
I _ I
I I lagoon _
LJ deep well _
IJ ocean _
I I other (describe) .
(quarter and year)
Cost Element:
Unit Price
Reference/Source:
Onsite Storage & Handling
Pretreatment
Container
Transportation Fee
Disposal Fee
Local Taxes
State Tax
Federal Tax
Total Disposal Cost
51
-------
Firm
Site
Date
WORKSHEET
10
Waste Minimization Assessment
Pfoc Unit/Oper.
Prnj Mn
Prepared By
Checked By
Sheet 1 of 1 Page of |
WASTE; STTREAM'SUMMARY
&EPA
Attribute
Waste ID/Name:
Source/Origin
Component/or Property of Concern
Annual Generation Rate (units )
Overall
Component(s) of Concern
Cost of Disposal
Unft Cost ($ per: )
Overall (per year)
Method of Management2
Priority Rating Criteria3
Regulatory Compliance
Treatment/Disposal Cost
Potential Liability
Waste Quantity Generated
Waste Hazard
Safety Hazard
Minimization Potential
Potential to Remove Bottleneck
Potential By-product Recovery
Wt.fW)
Sum of Priority Rating Scores
Priority Rank
Description1
Stream No.
Rating (R)
I(RxW)
RxW
Stream No.
Rating (R)
KRxW)
RxW
Stream No.
:
Rating (R)
2(RxW)
RxW
Notes: 1. Stream numbers, If applicable, should correspond to those used on process flow diagrams.
2. For example, sanitary landfill, hazardous waste landfill, onsite recycle, incineration, combustion
with heat recovery, distillation, dewaterlng, etc.
3. Rate each stream In each category on a scale from 0 (none) to 10 (high).
52
ft U.S. eOKWKCOOT miHTlNC omCE: 1993-750-002 / 80277
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