United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-008 Apr. 1984
Project Summary
Multimedia Pollution Assessment
of the Wood Products Industries
John Casana
This report presents a summary and
commentary on pollutants, abatement
technologies, and regulations in the
wood products industries. Information
was primarily obtained from a study per-
formed by Battelle Laboratories for the
U.S. Environmental Protection Agency
and available effluent guidelines
development.
Water pollution abatement legislation
has established guidelines based on
Best Practicable Control Technology
Currently Available (BPCTCA). These
guidelines primarily address conven-
tional pollutants, including five-day
biochemical oxygen demand (BODS),
total suspended solids (TSS) and pH. In
addition, guidelines based on Best
Available Technology Economically
Achievable (BATEA) and Best Conven-
tional Pollutant Control Technology
(BCPCT) are currently being established
to address conventional, priority (toxic),
and nonconventional (neither conven-
tional nor toxic) pollutants.
Existing external air pollution control
devices, in conjunction with internal
process controls, can be effective in the
reduction of air pollutants, especially
particulates and sulfur dioxide. Air
pollutants often limited by state govern-
ments include particulates and sulfur
dioxide, as well as total reduced sulfur
(TRS) compounds. Generally, southern
states have stricter particulate stan-
dards, while northwestern states have
stricter reduced sulfur compounds stan-
dards. The major impacts associated
with these pollutants are odor problems
and potential respiratory effects.
Solid waste-generation in the wood
products industry consists primarily of
wood wastes, wastewater treatment
plant sludge and refuse generated by
personnel activities. Although many
wood wastes are burned for heat re-
covery, sludge and refuse are typically
disposed of in landfills. Since sludges
generated by the wood preserving seg-
ment are considered a hazardous waste
under RCRA (May 1960), new landfilling
practices will need to be met by the in-
dustry for disposal.
The full report was submitted in fulfill-
ment of Contract No. 68-03-2606 by the
Edward C. Jordan Co., Inc., under the
sponsorship of the U.S. Environmental
Protection Agency. The report covers
the period May 1,1978, to June 1980, and
work was completed as of June 1980.
This Project Summary was developed
by EPA's Industrial Environmental Re-
search Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Objectives
This report is a summary and commentary
on pollutants, abatement technologies and
regulations in the wood products industries.
Summarized in this document are:
1. Wastewater effluent, air emissions and
solid waste generated by the wood pro-
ducts industries, and associated en-
vironmental impacts;
2. Abatement technology and associated
effects and economics; and
3. Pertinent existing and proposed legisla-
tion and its relation to items 1 and 2
above.
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The primary basis of this report is a study
performed by Battelle Laboratories for the
U.S. Environmental Protection Agency
(EPA). Available information from effluent
guidelines development and other sources
has been used to update and expand data
from the Battelle effort.
The wood products industries, for the pur-
pose of this report, have been broken down
into two main groups: 1) the pulp, paper,
and paperboard industry; and 2) the other
wood products industries. A brief descrip-
tion of each and its subcategories is
presented in the following paragraphs.
Industry Description
Pulp, Paper, and Paperboard
At the time of this study, the pulp, paper,
and paperboard industry consisted of ap-
proximately 730 operating facilities. Of these,
514 have been classed in specific subcate-
gories, and the remainder are in miscella-
neous subcategories composed of combined
process or unique process mills. Operations
vary from large integrated kraft pulp, paper,
and paperboard mills producing over 1.8
million kilograms per day (2,000 tons/day),
to small nonintegrated single machine mills
making less than 0.9 kkg/day (1 ton/day) of
product.
There are three general classifications of
mills: integrated mills, secondary fiber mills,
and nonintegrated mills. At integrated mills,
pulp is produced from wood and nonwood
raw materials (e.g., hemp or flax); paper and
board products are produced onsite. At
secondary fiber mills, no pulp is produced
onsite; most of its furnish is derived from
wastepaper. At nonintegrated mills, the fur-
nish consists of purchased wood pulp or
other fibers. No pulp is made onsite, but
some wastepaper can be used, as long as
the mill does not have a complete deinking
process.
Pulping processes at the integrated mills
range from simple groundwood operations,
using only mechanical defibration of full logs
and limited bleaching operations, to the
complex dissolving pulp mills employing ex-
tensive chemical pulping operations and at-
tendant recovery systems coupled with
multistage bleaching operations. Also in-
cluded with the integrated pulp mills are
those producing pulps from a variety of non-
wood fibers such as flax, hemp, cotton,
abaca, and sisal. Pulping operations include
groundwood and modified groundwood op-
erations, sulfite (acid) processes, unbleach-
ed and bleached kraft or soda processes
(alkaline), and modified high-yield processes
utilizing mild chemical treatments coupled
with mechanical defibration.
Mills using secondary fiber are a large and
growing segment of the industry. At these
mills, wastepaper is utilized in various forms.
At one extreme are processes involving the
direct slushing of wastepapers with no ad-
ditional processing, followed by conversion
into coarse products such as construction
papers, corrugating media and other coarse
board stock. At the other extreme are mills
using high quality wastepapers which subse-
quently are deinked by chemical means,
screened, cleaned, and processed through
multistage bleaching systems in a manner
very similar to wood pulping. High quality
deinking pulps are utilized in the production
of fine quality tissue, printing, and business
papers.
Fibers are purchased by nonintegrated
mills, which manufacture a wide range of
products. The products range from specialty
board items through the highest quality fine
papers.
The U.S. pulp, paper, and paperboard in-
dustry is concentrated in the northeastern,
southern, and western states.
Other Wood Products Industries
The other wood products industries are
diverse and are broken down in the follow-
ing point source categories.
Veneer/Plywood
In 1972 there were approximately 593
veneer plywood plants operating in the
United States. Of these, approximately 366
processed hardwood, and 227 processed
softwood. Hardwood products are used for
decorative purposes. Softwood products are
used in structural applications.
The typical hardwood plywood plant is a
small, privately-owned mill producing 5 to 10
million ft2 of product per year. This is in con-
trast to the production pattern in the soft-
wood plywood section, which is typified by
a mill with a 100 to 125 million ft2 output per
year. Furthermore, softwood plywood plants
tend to be multiplant operations owned by
a broad-based forest products company.
Particleboard
The particleboard industry consists of ap-
proximately 74 plants. Producers range from
large multi-forest product companies pro-
ducing particleboard from their wood
wastes, to relatively small furniture com-
panies producing particleboard for captive
consumption. The largest four firms control
approximately 36 percent of the industry
capacity.
Particleboards are board products that dif-
fer from conventional fiberboards. They are
composed of distinct particles of wood or
other ligno-cellulosic materials that are
bonded together with an organic binder. The
"particles" vary in size and must be dis-
tinguished from the fibers used in insulation
and hardboard. Other terms used for par-
ticleboard include chipboard, flakeboard,
silverboard, shaving board, and wood waste
board.
Millwork
The millwork industry manufactures
molding, doors and windows, and cabinetry.
The industry is quite fractionated with the
eight largest companies producing only 13
percent of the output in 1970. Among pro-
ducers of molding, which accounts for 20
percent of the industry output, 35 companies
possess approximately 80 percent of the
capacity.
Some molding companies are integrated
with sawmills, although most are separate.
Local producers of windows, doors, and
cabinetry are usually small operations. The
total number of plants is not well-docu-
mented.
Structural Wood Members
In 1972, 642 firms were actively engaged
in the manufacture of structural wood mem-
bers and were reported to be operating 678
establishments. The industry is quite diverse,
with the top 50 companies supplying only 46
percent of the total shipments. This industry
is primarily engaged in the manufacture of
laminated or fabricated trusses, arches, and
other structural members of lumber.
Wood Furniture and Fixtures
The large number of products included in
this group prohibits a listing of each. The
processes include the machining and fabrica-
tion (fastening or gluing) of primary forest
products such as lumber, plywood, and
board.
Gum and Wood Chemicals
Major products from this industry include:
wood turpentine, wood rosin, tall oil, fatty
acids, gum rosin, gum turpentine, and pure
oil. Twelve major companies account for the
majority of production in this industry. The
more efficient use of rosin for sizing in the
paper industry and decline in the use of gum
for naval stores indicate a downward trend
for this industry in the future.
Wood Preserving
There are approximately 415 companies
engaged in wood preserving in the United
States. Fifty percent of the industry capac-
ity is controlled by ten companies. Over
three-quarters of the plants are concentrated
in two distinct regions. One area extends
from east Texas to Maryland and corre-
sponds roughly to the natural range of
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southern pines, the major species utilized.
The second, smaller area is located along the
Pacific Coast, where Douglas fir and western
red cedar are the predominant species.
The wood preserving industry applies
chemical treatment to round or sawn wood
products for the purpose of imparting insec-
ticidal, fungicidal, or fire resistant properties
to the wood. The three most prevalent types
of preservatives used in wood preserving are
creosote, pentachlorophenol (PCP), and
various formulations of water-soluble in-
organic chemicals, the most common of
which are the salts of copper, chromium,
and arsenic. Fire retardants are formulations
of salts, the principal ones being borates,
phosphates, and ammonium compounds.
Eighty percent of the plants in the United
States use at least two of the three types of
preservatives. Many plants treat with one or
two preservatives plus a fire retardant.
Insulation Board
There are 16 plants in this subcategory
that use wood as the predominant raw
material. Insulation board is a form of fiber-
board, which in turn is a broad generic term
applied to sheet materials constructed from
ligno-cellulosic fibers. Insulation board is a
"non-compressed" fiberboard, which is dif-
ferentiated from "compressed" fiberboards,
such as hardboard, on the basis of density.
Densities of insulation board range from
about 0.15 to a maximum 0.50 g/cu cm (9.5
to 31 Ib/cu ft).
Hardboard
There are 16 wet process hardboard mills
in the United States. Hardboard is a form of
fiberboard, which is a broad generic term ap-
plied to sheet materials constructed from
ligno-cellulosic fibers. Hardboard is a "com-
pressed" fiberboard, with a density over 0.50
g/cu cm (31 Ib/cu ft). The thickness of hard-
board products ranges between 2 and 13 mm
(nominal 1/12 to 7/16 in.)
Production Trends
Pulp, Paper and Paperboard
Pulp, paper, and paperboard production
capacity have exhibited moderate but steady
growth in recent years.
Other Wood Products
Lumber production has fluctuated with no
trend in recent years. Particleboard produc-
tion peaked in 1973 and then began declin-
ing. Hardwood plywood production steadily
declined, while prefinished hardwood ply-
wood made from purchased pulp increased
dramatically over the past decade. Softwood
plywood production experienced steady
gains over the same period.
Pollution Abatement Costs
According to an advance report from the
U.S. Department of Commerce, Bureau of
the Census, United States manufacturing
establishments spent $3.586 billion on pollu-
tion control in 1977. This total represents a
2 percent increase over 1976 capital expen-
ditures. Operating costs for pollution abate-
ment totaled $5.485 billion in 1977,
representing a 21 percent increase over the
1976 total of $4.359 billion. Costs incurred
by the lumber and wood products industry
(SIC 24) and the paper and allied products
industry (SIC 26) are summarized in the full
report.
There was a slight reduction in capital ex-
penditures for pollution control by the paper
and allied products industry in 1977. This in-
dicates that many mills have already com-
pleted the construction of required
environmental control systems. Pollution
control operating costs rose by 28 percent
for the paper and allied products industry
from 1976 to 1977. Most of the costs in-
curred relate to air and water pollution con-
trol efforts.
Summary, Conclusions, and
Recommendations
Water Pollution
Water pollution abatement legislation has
resulted in the establishment of effluent
limitations guidelines based on best prac-
ticable control technology currently available
(BPCTCA). These guidelines primarily ad-
dress conventional pollutants, including
5-day biochemical oxygen demand (BOD5),
total suspended solids (TSS) and pH. In ad-
dition, guidelines based on best available
technology economically achievable
(BATEA) and best conventional pollutant
control technology (BCPCT) are currently
being established to address conventional,
priority (toxic), and nonconventional (neither
conventional nor toxic) pollutants.
Conventional Pollutants
Pulp, Paper, and Paperboard In-
dustry
Annual average discharge information for
calendar year 1976 indicates that at least one
pulp and paper mill in each industry sub-
category was meeting the BPCTCA guide-
lines which went into effect in July 1977. The
sampling period reflected a time of construc-
tion and/or startup of many effluent treat-
ment facilities. Therefore, it is expected that
many more mills are currently meeting the
BPCTCA guidelines. A continuing review of
effluent monitoring data is recommended to
enforce appropriate discharge limits.
Primary/biological effluent treatment is
widely used in the wood products industry.
These systems achieve approximately 80 per-
cent removal of BOD5 and TSS prior to dis-
charge. Various additional effluent treatment
systems may be installed to further reduce
conventional pollutants. Chemical clarifica-
tion, for example, may serve as a tertiary
treatment after biological treatment. One
such system has been successfully installed
in a chemi-mechanical pulp and paper mill
and is achieving annual average final effluent
BOD5 and TSS concentrations of 12 mg/l
each. Specific studies are recommended to
further establish optimum design charac-
teristics for chemical clarification of various
wood products effluents, and associated
sludge production, costs, and other aspects
of non-water quality impacts of the tech-
nology.
In many cases, the installation of produc-
tion process controls can reduce the flow
and/or pollutant load to effluent treatment
systems and the final discharge. Examples
of these controls are spill collection systems
to minimize the potential for shock loading,
countercurrent pulp washing for flow reduc-
tion, and liquor evaporation for material and
heat recovery as well as flow and pollutant
reduction. The cost-effectiveness of produc-
tion control alternatives should be carefully
compared to that for effluent treatment
technologies at specific facilities.
Conventional pollutants currently being
discharged have been shown in two specific
studies to have minimal effects on receiving
waters after mixing. This impact, however,
is dependent in part on the relative flows of
effluent and receiving water. A mill discharg-
ing to a small stream may have a greater im-
pact than a similar discharge to a larger
stream. Additional site-specific evaluations
are needed to verify the magnitude of this
phenomenon.
Existing effluent guidelines for TSS do not
distinguish between settleable and nonset-
tleable solids. The impact associate with
each, however, can vary. For example, set-
tleable solids are more readily removed by
treatment, while those not removed may
tend to deposit on the stream bottom. This
can have adverse impacts on water quality,
benthic organisms, and stream aesthetics.
Nonsettleable solids, on the other hand, are
not easily removed by conventional treat-
ment and tend to remain in suspension long
after being discharged. As such, they can
impact water quality far downstream of the
mill. Additional data relating the actual
magnitude of these impacts is needed.
Other Wood Products Industries
Conventional pollutant discharges from
other wood products industries are usually
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highly variable and less well-documented
than those for the pulp and paper industry.
Nonconventional Pollutants
Nonconventional pollutants include any
that are not specifically identified as conven-
tional or priority pollutants in the current
legislation. These include color, foam and a
variety of wood-derived toxicants which
were not included in the priority pollutant list.
Color can cause adverse aesthetic effects
and can hinder light penetration in receiving
waters, which can affect aquatic life. The
major source of color in the pulp, paper and
paperboard industry is the first caustic ex-
traction stream in bleached kraft pulp mills.
Several production process controls in-
cluding alternative bleaching sequences and
spill controls can reduce raw caustic extract
color. Chemically assisted precipitation in ad-
dition to conventional and toxic pollutant
reduction, can reduce final effluent color
from 50 to 90 percent cost.
Foam can produce adverse aesthetic ef-
fects in receiving waters. The situation is
complicated because many compounds con-
tributing to foam are believed to be wood-
derived and occur naturally in many streams.
Toxic wood-derived compounds include
resin and fatty acids such as abietic, de-
hydroabietic, isopimaric, pimaric, oleic,
linoleic, and linolenic. Chlorinated analogues
resulting from pulp bleaching include epoxy-
stearic acid, dichlorostearic acid, mono-
chloroabietic acid, dichloroabietic acid,
trichloroguaiacol and tetrachloroguaiacol.
Due to their dependency on wood source,
process controls and other variables, it is ex-
tremely difficult to formulate a predictive
relation for toxic pollutants. Additional study
is recommended in this area.
Priority and other toxic pollutants con-
tribute to a limited but variable toxicity in
many pulp and paper mill effluents. A major
cause for concern over this toxicity is then
very large effluent volumes. When discharg-
ed, these materials can have lethal and sub-
lethal effects on aquatic life. Additional study
is recommended to further establish the
relative contribution of each compound to
the toxicity of the wastes and possible syn-
ergistic effects.
Research is needed to identify the precise
causes of foam. Many of these wood-derived
compounds, such as resin acids, fatty acids
and their chlorinated analogues, have also
been shown to be major causes of the ob-
served toxicity in pulp, paper and paperboard
mill effluents. The foam separation process
has been shown to effectively treat foam and
toxicity, but has little effect on BODS and
TSS.
Priority (Toxic) Pollutants
Wood Products
Priority (toxic) pollutants (49, 18 in wood
preserving, also arsenic) known to be pre-
sent in wood products industries waste in-
clude chloroform (from pulp bleaching);
heavy metals (chromium, copper, lead, mer-
cury and zinc) from papermaking additives
and wood preserving; PCBs (from waste
paper); and pentachlorophenols (PCP) and
PNAs (from wood preserving).
Existing biological treatment has detoxified
effluents between 60 and 80 percent of the
time. Periods of toxic discharge have been
associated with mill upsets. These toxicity
reductions can be improved through the use
of flow equalization and production process
controls. The detoxification efficiency can be
further enhanced by installing technologies
such as foam separation, chemically assisted
clarification, or carbon adsorption in addition
to biological treatment.
Chemical coagulation of wood preserving
wastes with 150 mg/l alum on a laboratory
scale was shown to be capable of a 50 to
75 percent PCP reduction. This resulted in
final effluent PCP concentrations of 3 to 10
mg/l.
Additional research is recommended to
further establish the treatability of various
wood product effluents, the optimum design
parameters of applicable technologies; and
the cost and other non-water-quality aspects
for installing selected technologies.
Nonpoint Source Pollution
Nonpoint source pollutants from
silviculturaf activities include sediment (TSS)
and its associated BOD5, nutrients, her-
bicides, rodenticides, and insecticides. These
can impact the receiving waters nearby.
Nutrients from fertilization can alter the
trophic state of these waters. Proper man-
agement practices, including buffer strips ad-
jacent to streams and the avoidance of direct
chemical application to surface waters, can
minimize adverse water quality impacts from
nonpoint sources. Continued monitoring is
recommended to ensure that these practices
are being adhered to and that no significant
adverse impacts occur.
Air Pollution
Existing external air pollution control
devices, in conjunction with internal process
controls, can be effective in the reduction
of air pollutants, especially particulates and
sulfur dioxide. Air pollutants often limited by
state governments include particulates and
sulfur dioxide, as well as total reduced sulfur
(TRS) compounds. Generally, southern
states have stricter paniculate standards.
while northwestern states have stricter
reduced sulfur compounds standards. The
major impacts associated with these pol-
lutants are odor problems and potential
respiratory effects.
Pulp, Paper and Paperboard Industry
Pulp, paper and paperboard mill recovery
furnace operations are those likely to be af-
fected by stringent regulations. The initial
kraft mill furnace designs did not seriously
consider the control of reduced sulfur emis-
sions. Particulate discharges from over-
loaded furnaces are great, and the sulfur
dioxide emissions from sulfite mill recovery
furnaces are often too high to meet the stan-
dards of some states. Secondary odor con-
trols or replacement of the furnace are
probable requirements for meeting state
standards. In the case of odor, the sensitiv-
ity of the human nose to TRS is so high, that
it is almost impossible to completely elimi-
nate this impact.
The pulp, paper and paperboard industry,
because it is a large offender, has done a
significant amount of groundwork for the
other wood products industries in the field
of air pollution control. Hydrocarbon and car-
bon monoxide emissions of the veneer/ply-
wood industry can be incinerated, and
paniculate emissions of the particleboard in-
dustry can be controlled by conventional
pollution control devices. These are the same
means of control used in the pulp and paper
industry.
Air emissions from the wood preserving
industry can exceed current air pollution
regulations. The sources of emissions are:
a dense plume of volatilized organics when
a pressure vessel is opened and the newly
treated wood is removed and cooled; and
paniculate emissions from the vacuum ex-
haust, as well as in the exhaust during steam
cleaning. A control technology to reduce the
volatilized organics is to reduce the tempera-
ture of the newly treated wood as it is re-
moved from the pressure vessel. This is
accomplished by the placement of spray
nozzles just off the open end of the pressure
vessel, to create a water blanket to cool the
wood as it is slowly removed.
Outdated kraft mill recovery boilers are
likely to be the major factor in mills not
meeting state air pollution standards. Re-
placement of the boilers may be the only way
to meet reduced sulfur compounds and par-
ticulates standards, but such replacement
will be expensive. An economic analysis
which would include a survey of furnaces
needing replacement based on age and emis-
sions, an estimate of replacement cost, and
examination of the industry's ability to ab-
sorb the cost is suggested.
4
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The use of cross-recovery systems in
sulfite and NSSC mills may produce signifi-
cant sulfur dioxide emissions. A study may
be needed to evaluate the impact of these
emissions and to evaluate the applicable con-
trol technologies. One technology that
should be investigated is the use of regener-
able stack gas desulfurization processes.
Solid Wastes
Solid waste generation in the wood pro-
ducts industries consists primarily of wood
wastes, wastewater treatment plant sludge
and refuse generated by personnel activities.
Although many wood wastes are burned for
heat recovery, the most common means of
sludge and refuse disposal at present is land-
filling.
There is no consolidated information con-
cerning the practices at the landfill sites for
these wastes. Once the current evaluation
efforts have resulted in classification of land-
fills in the U.S., it should be verified that the
wastes from this industry are being placed
in adequate sites.
If chemically assisted clarification were im-
plemented on an industry-wide basis in the
pulp, paper, and paperboard industry, it is
estimated that wastewater treatment plant
sludge production would increase by ap-
proximately 20 to 30 percent (dry solids
basis). This sludge would probably be dif-
ficult to dewater and dispose of, and would
have environmental and economic impacts.
A study is needed to determine the magni-
tude thereof.
Additional investigation should be per-
formed in the area of energy recovery from
solid wastes (including sludges). The poten-
tial energy savings, economic cost, and air
emissions must be balanced against the
economic and environmental costs of land-
filling. Also, alternate solid waste disposal
and utilization technologies (such as com-
posting) should be investigated further for
use in the wood products industries.
John Casana is with Edward C. Jordan Co., Inc., Portland, ME 04112.
Donald Wilson is the EPA Project Officer (see below).
The complete report, entitled "Multimedia Pollution Assessment of the Wood
Products Industries." (Order No. PB 84-160 266; Cost: $23.50, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati. OH 45268
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
U.S. GOVERNMENT PRINTING OFFICE: 1964-758-102/932
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