Environmental Paper Network

Glossary of Key Terms and Abbreviations

A-K | L-R | S-Z

Note: Terms listed and defined in this glossary are in boldface. Terms which may be of particular interest to the reader in a given context, but are not listed in the glossary, are in italics.

Adsorbable organic halogens (AOX): Measure of the total amount of halogens (chlorine, bromine and iodine) bound to dissolved or suspended organic matter in a wastewater sample. For pulp, paper and paperboard wastewaters, essentially all of the organic substances measured as AOX are chlorinated compounds that result from the bleaching of pulps with chlorine and chlorinated compounds such as chlorine dioxide and hypochlorite. AOX provides information about the quantity of chlorinated organic compounds in wastewater, and thus contains a broad mix of compounds that have different chemical properties. The actual composition of AOX in pulp mill effluent varies from mill to mill, depending on the wood species used and the process parameters.

"Although AOX concentrations can be used to determine the removal of chlorinated organics to assess loading reductions, they do not provide information on the potential toxicity of the effluent, and therefore, are not appropriate to evaluate the potential impacts on the environment. Although no statistical relationship has been established between the level of AOX and specific chlorinated organic compounds, AOX analysis can be an inexpensive method for obtaining the 'bulk' measure of the total mass of chlorinated organic compounds." (U.S. EPA, Regulatory Impact Assessment of Proposed Effluent Guidelines and NESHAP for the Pulp, Paper and Paperboard Industry, (Washington: Office of Water, EPA-821-R93-020, November 1993), pp. 7-25 - 7-26)

AF&PA: The American Forest & Paper Association.

Agricultural residues: By-products of the production of food and other crops that contain fibers that can be used for papermaking.

Air-dried metric tons (ADMT): Pulp with 10% water content by weight. One ADMT is equivalent to 0.9 oven-dried ton/metric ton of pulp (ODMT).

Air-dried tons of final product (ADTFP/ADMTFP): Tons or metric tons of final product made at a mill.

Alkaline papermaking: Process of producing papers under neutral or alkaline conditions. The major force behind the conversion from acid to alkaline papermaking is the greater strength of the alkaline sheet, which permits higher levels of clay and calcium carbonate filler. Additionally, maintenance costs for alkaline papermaking are less because such systems are less prone to corrosion, and are more easily closed than acid systems.

Alum: Also called aluminum sulfate. (1) Chemical release agent, used when pure fiber furnish is run at low basis weight to prevent sticking to the paper machine presses. (2) Papermaking chemical commonly used for precipitating rosin sizing onto pulp fibers to impart water-resistant properties to the paper.

American Forest & Paper Association: The trade association for the U.S. pulp, paper and forest products industry.

Anaerobic : Biochemical process or condition occurring in the absence of oxygen.

Anthraquinone: Chemical added to the digester that increases the amount of lignin removed from kraft pulp while maintaining its strength.

Artificial regeneration: Method for producing a new stand of trees following harvesting, in which tree seedlings (or more rarely, seeds) are planted. Most often used in even-aged silvicultural systems.

Ash: Inorganic matter present in the paper sheet, such as clay or titanium dioxide.

Base stock: Paper that will be further processed, as in coating or laminating.

Basis weight: The weight of a ream (500 sheets) or other standardized measure of a paper. Calculations are based on sheet sizes of either 11" x 17" or 17" x 22", because paper mills produce the larger-size sheets and then ship them to converters, who cut the sheets to standard letter or legal sizes. A proposed international standard unit for basis weight is called grammage, which is grams per square meter; this international standard unit is not widely used in the U.S.

Beating: The mechanical treatment given papermaking materials to prepare them for forming on the paper machine into paper or board of precise characteristics.

Bedding: A site-preparation technique in which soil is raised from a few inches to a few feet high to provide an elevated planting or seed bed; used primarily in wet areas to improve drainage and aeration for seeding.

Best Management Practices or BMPs: In this report,, forestry practices specified in state-level forest management guidelines or legislation. BMPs encompass the practices required by the mandatory forest practice acts in some states as well as the voluntary or quasi-regulatory BMP programs in other states.

Biochemical oxygen demand (BOD): Amount of oxygen required by aerobic (oxygen-requiring) organisms to carry out normal oxidative metabolism or the amount required by oxidation of metabolic by-product from anaerobic organisms in water containing organic matter. Thus, BOD measures the amount of dissolved organic material that is degraded naturally once it enters a mill's receiving waters. For regulatory purposes, BOD is most often measured over a five-day period in the United States. The BOD in a test bottle can consume oxygen well in excess of 100 days, and the five-day test may capture only 50-75% of the total BOD.

Biodiversity: Most broadly, biodiversity encompasses the diversity of life on the planet. Biodiversity includes genetic diversity, the diversity of information encoded in genes within a species; species diversity, the diversity and relative abundance of species; and community/ecosystem diversity, the diversity of natural communities.

Biomass: Mass of organic matter. E.g., the "biomass removed in harvesting" refers to the amount of organic matter -- mostly wood in trees, but also twigs and leaves -- removed at harvest.

Black liquor: Spent, lignin-rich cooking liquor generated in the kraft pulping process.

Bleaching: Chemical treatment of pulp fibers for the purpose of: (1) increasing pulp brightness, (2) improving cleanliness by disintegrating contaminating particles such as bark and (3) improving brightness stability by reducing the tendency of bleached pulp to turn yellow. Bleaching removes residual lignin chemicals. .

Bonding strength: Cohesiveness of fibers within a paper. Paper with good bonding strength will not pick during the printing process.

Book paper: Also called text paper. Any type of paper suitable for printing, exclusive of newsprint and boards.

Boxboard: Paperboard used to make folding boxes, set-up boxes and carton stock. May be plain, lined or clay-coated.

Brightness: Light-reflecting property of paper or pulp. Brightness measurements compare paper and pulp with a reference standard (measured on a scale of 1 to 100 where 100 represents the reflectance of magnesium oxide). Bleached kraft pulps range in brightness from the low 80s to over 90. Unbleached mechanical pulps range from 55 to 62.

Broke: Machine trim or damaged paper that is pulped and returned to the papermaking process within the mill.

Broker: Purchaser of secondary materials who sells the materials to manufacturers. Brokers typically do not process raw materials for resale.

Buffer strip: See streamside management zone.

Bulk: Thickness of a sheet of paper in relation to its weight.

Bursting strength: Measurement of the strength of a piece of paper to withhold pressure.

Buy-back center: Facility that purchases secondary materials, usually from the public, and resells them to brokers or manufacturers. Buy-back centers may or may not process the recyclables.

Cable logging: System of transporting logs from stump to landing by means of steel cables and winch. This method is usually preferred on steep slopes, in wet areas, and for erodible soils where tractor logging cannot be carried out effectively.

Calender: Also called calender stack. Vertical stack of sheet or cast-iron rolls, at the dry end of the machine, through which the paper sheet is passed for smoothing and gloss improvement.

Calendering: The process of passing paper through an assembly of rolls that have polished surfaces. The rolls compact and smooth the paper, increasing the sheet's gloss and smoothness.

Caliper: Sheet thickness measured under specified conditions, usually expressed in thousandths of an inch (points or mils).

Capacity: The amount of pulp, paper or paperboard that a a paper machine or mill is capable of producing over an extended period of time with the full use of its equipment, adequate raw materials and labor and full demand for its products. Capacity is often slightly higher than actual production.

Carbon black: Finely processed forms of carbon derived from the incomplete combustion of natural gas or petroleum; used principally in ink and rubber.

Carbon dioxide (CO2): Greenhouse gas associated with global climate change that esults from the complete combustion of biomass (wood waste) and fossil fuels.

Cellulose: Polymer of sugar units that forms transparent, hollow and flexible tubes. It is the most abundant natural polymer produced by plants.

Chemi-thermomechanical pulp (CTMP): Variation of thermomechanical pulp (TMP) produced by pulping that reduces energy consumption for certain paper grades by combining thermal pretreatment with chemical methods. A stronger and brighter version of CTMP is bleached chemi-thermomechanical pulp (BCTMP).

Chemical oxygen demand (COD): Amount of oxidizable compounds (composed of carbon and hydrogen) present in the water. Since an effluent-treatment system removes most of the organic material that would be degraded naturally in the receiving waters, the COD of the final effluent provides information about the quantity of more persistent substances discharged into the receiving water.

Chemical pulp: Pulp produced from wood that has been cooked with various chemicals; used to produce many grades of printing papers and some paperboard grades, such as SBS.

Chipboard: Low-density board made from waste paper; used in low strength applications.

Chopping: Mechanical site preparation treatment whereby remaining vegetation is concentrated near the ground and incorporated into the soil to facilitate burning or establishment of seedlings.

Clarifier: Process water storage tank in which suspended solids are allowed to settle.

Clay: Natural, fine-grained material used as filler and as coating pigments in paper manufacture.

Clearcutting: Harvesting/regeneration method in which all merchantable trees (commercial clearcutting) or all trees (silvicultural clearcutting) in a stand are harvested in one operation. Clearcutting is also used in even-aged silviculture to regenerate an even-aged stand of desired shade-intolerant trees. In practice, most clearcuts are commercial clearcuts.

Coarse woody debris: Also called large woody debris. Downed large wood on the forest floor, such as fallen trees and limbs. When such debris falls into streams, it creates waterfalls and pools -- important physical structures for fish habitat and other stream functions. In natural forests of some regions (e.g., the Pacific Northwest), coarse woody debris on the forest floor also provides important functions as it slowly decays, returning nutrients to the soil, storing water for use in dry periods, and providing animal habitat. Coarse woody debris develops naturally in unmanaged forests, as trees die and decay, and may also be created by forest management (see also Logging debris).

Coated freesheet: Coated papers containing 10% or less of mechanical pulp (mostly stone groundwood and/or refiner) in their furnish.

Coated groundwood: Coated papers containing more than 10% mechanical pulp (mostly stone groundwood and/or refiner). Coated groundwood papers also contain softwood bleached kraft pulp to minimize breaks in the printing press.

Coated paper: Paper or paperboard that has been coated to improve printability and appearance. Paper may be coated on one or both sides.

Coating: (1) Act of applying a coating to the surface of paper or paperboard. (2) Material used as a coating; clay is the most commonly used coating.

Cockle: Ripple or waviness of a sheet caused by improper drying.

Color: Used to describe colored wastewater discharge from chemical pulping, pulp bleaching or colored-paper manufacture. The wastewater is colored by the lignin and lignin derivatives present in spent cooking liquors.

Commercial printing: Wide array of promotional literature, including annual reports and direct mail products not included under catalogs, such as materials sent out in bulk mail by banks, financial services companies, credit-card marketers and others. Commercial printing products use both uncoated and coated papers.

Commercial thinning: Silvicultural practice performed in even-aged forests in which some merchantable trees are harvested, usually for pulpwood, to provide greater light, soil moisture and nutrients to the remaining stand.

Commodity grade: Mass-produced paper grades, typically made at large pulp and paper mills. Includes grade with more than 1.5 million tons per year of total production in the United States, such as linerboard, newsprint, and the major uncoated freesheet grades (e.g., 20 lb. cut-size, 50 lb. offset).

Community: Collection of animal and plant species present in a given location; generally viewed as also encompassing the interactions between different species.

Compost: (1) Nutrient-rich mulch of organic soil produced through aerobic digestion of mixtures of food, wood, manure and/or other organic material. (2) The process of producing compost.

Consistency: The percentage of cellulose fibers in a pulp slurry,.

Containerboard: Single-ply and multi-ply combinations of linerboard and corrugating medium used to make boxes and other shipping containers.

Conversion: Transformation of large rolls of paper or paperboard into a variety of products, such as forms, envelopes, bags, boxes and folding cartons.

Converter: Company that converts paper from its original form into usable products like bags and boxes.

Cook: To treat wood with chemicals, under pressure and/or extreme heat, to produce pulp for making paper and paperboard.

Cooking liquor: Chemical solution used to pulp wood.

Core: In the center of a roll, the shaft around which the web of paper is wound. Cores are either metal or cardboard and are either returnable or disposable.

Corrugating medium: Paperboard (made from chemical, semi-chemical and/or recycled pulps) that is passed through a fluting machine and used as the middle layer of corrugated boxes.

CUK: Coated unbleached kraft paperboard. Also known as solid unbleached sulfate or coated natural kraft paperboard. The abbreviations "SUS" and "CNK" have been trademarked by Riverwood International and Mead Corp., respectively.

Cumulative effect: Impact on the environment that results from the incremental impact of an action when added to other past, present and reasonably foreseeable future actions.

Curl: In a photocopy machine, output curl is a result of an interaction of the heating in the fuser with the paper's structure and moisture content. Curl that is built into the paper as packaged is called as-packaged curl.

Cylinderboard: Paperboard made on a cylinder machine.

Cylinder machine: An older paper paper machine technology used primarily to make 100% recycled paperboard. In such a machine, 6-9 rotating mesh cylinders are immersed in vats of pulp; the paperboard is formed as water drains from the cylinder. The wet sheet is transferred off the cylinder onto a felt or onto other sheets to make a multi-layer product. Pressing and drying follow this step.

Deinked Market Pulp (DMP): Pulp made from recovered paper by mills that receive high-grade deinking papers (defined below) and remove the ink and contaminants. DMP is produced in sheets as wet-lap pulp (about 50% moisture) or air-dried form and is sold to paper producers who blend it with virgin pulp for use on existing paper machines.

Deinking: Separation and removal prior to paper formation of ink and other contaminants from wastepaper slurry by screening, washing, flotation, chemical treatment and bleaching.

Delignification: The process of removing lignin from wood or non-wood fibers.

Density: The weight of a paper compared to its volume. Dense papers are made from well-beaten or hydrated pulp.

Die cut: Paper and paperboard products cut by a metallic die to specified dimensions or forms.

Digester: Pressurized vessel in which wood chips are cooked to separate fibers from each other and to remove contaminants.

Dimensional stability: Ability of paper to retain its dimensions in all directions under the stress of production and changes in humidity. This property allows paper to resist curl and cockle. Resistance to curl is extremely important, as curl is a major cause of copy machine jams. Dimensional stability is also determined by a sheet's reactivity and paper formation.

Dioxins: Term used throughout this book to describe the families of chemicals known as chlorinated dibenzo-p-dioxins and dibenzo-p-furans. These families consist of 75 different chlorinated dibenzo-p-dioxins and 135 different chlorinated dibenzo-p-furans. These molecules can have from one to eight chlorine atoms attached to a planar carbon skeleton. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) are two of the most toxic members of this family of compounds. If dioxins are detected in the releases from bleaching processes that expose unbleached pulp to elemental chlorine, the dioxins are most likely to be TCDD and TCDF.

Dirt: Loose material from all manufacturing sources, e.g., slitter, trimmer dust, lint, starch, loose coating pigments and loosely bonded fibers. With respect to paper recycling, "dirt" can refer to a range of small contaminants.

Disking: Also called harrowing. Mechanical site preparation method of scarifying the soil (i.e., scraping to expose mineral soil) to reduce competing vegetation and to prepare a site to be seeded or planted.

Downtime: Downtime occurs when a paper machine is stopped for repairs. Shutting down a paper machine for vacation or normal maintenance is referred to as scheduled downtime.

Drop out: Condition that occurs during photocopying when portions of originals do not reproduce, especially colored lines or background areas.

Dry end: Section of a paper machine where the driers, cutters, slitters and reels are located; the paper web is formed into a dry sheet in this part of the machine.

Dryers: Part of paper machine where water is removed from wet paper by passing it over rotating, steam-heated, cylindrical metal drums, or by running it through a hot air stream.

Ecosystem: Ecosystems encompass natural communities and also include nonliving components, both structural (soil types) and functional (processes such as disturbance patterns and energy flows in and out of the ecosystem).

Effluent: Wastewater that has been discharged either to a sewer or to a stream or other body of water.

Electrical properties: Properties of paper that determine how it responds to an electrical charge, and how static electricity will be dissipated from the sheet. Electrical properties affect the quality of the image transfer in copy machines and laser printers. If the sheet does not exhibit uniform electrical properties, the result can be uneven application of toner on a page. Electrical properties are affected by the smoothness of the sheet, by surface sizing agents and by changes in moisture content.

Elemental chlorine: Chlorine gas (Cl2).

Elemental chlorine-free (ECF): Bleaching processes that substitute chlorine dioxide for elemental chlorine and sodium hypochlorite in the bleaching process.

Even-aged management: Class of silvicultural systems that maintains even-aged stands by periodically removing the forest canopy in a single operation and regenerating a new stand at one time. Harvesting/regeneration methods used in even-aged management include clearcutting, the seed-tree method and the shelterwood method.

Feedstock: Raw material used to make paper or paperboard.

Feet per minute : Abbreviated as fpm, this term usually refers to the speed at which the forming paper web traverses the length of the paper machine.

Felt side: Top side (side opposite the wire) of a paper sheet. Felt is a woven belt made of cotton, metal or synthetic materials used to transport forming paper web on the paper machine.

Fertilizer: Plant nutrients applied to forest soils, usually in chemical forms that are readily taken up by plants (e.g., phosphorus is applied as phosphate).

Fiber fractionation: Separation of pulp into a long and short fiber fraction. Used by paper and paperboard mills to direct long fibers to the outer plies and short fibers to the inner plies of a multi-ply board.

Fiber furnish: Recovered paper used to make paper or board with recycled content.

Filler: (1) Substances, such as clay, precipitated calcium carbonate, and other white pigments, added to pulp to improve a paper's printability. (2) Inner layers of multi-ply paperboards.

Filtrate : Water that is either pressed or washed out of the pulp during the pulping and bleaching processes; once the water has been discharged to a sewer it becomes effluent.

Fine papers: Printing and writing papers.

Finish: Surface contour and characteristics of a paper sheet measured in terms of smoothness, gloss, absorptiveness and print quality.

Finishing operations: Supplementary operations to printing such as binding, finishing and distribution. The demands of finishing and postpress operations include folding, die-cutting, cutting, trimming, scoring, stitching, gluing and perforating.

Flotation deinking: In a paper recycling system, removal of ink by a process of adding surfactants to the pulp and pumping bubbles of air through the mixture. The hydrophobic ink particles attach to the air bubbles, float tothe surface of the pulp and are skimmed off.

Folding carton: Paperboard boxes that are creased and folded to form containers that are generally shipped and stored flat and erected at the point where they are filled. Folding cartons are designed to contain and present products, and are generally small enough to hold in one hand.

Forest canopy: Topmost layer of tree vegetation, also called the overstory.

Formation: Term used to describe the process of forming the paper sheet or paperboard on a paper machine.

Fourdrinier machine: Paper machine comprised of a rapidly moving horizontal screen fitted with a headbox to meter the pulp onto the wire.

Freesheet: Paper that contains less than 10% groundwood pulp.

Freeness: Also called drainage. Ability of pulp and water mixture to release water.

Fuelwood: Wood used for conversion to some form of energy, primarily residential use.

Functionality: Ability of a paper product to meet the users's performance requirements, such as running in office equipment, on an offset printing press, packaging consumer and industrial items, presenting a product or commnication with a customer, and meeting the needs of the ultimate user.

Furnish: Also called stock. Various pulps, dyes and additives blended together in the stock preparation area of a paper mill, and fed to the wet end of a paper machine to make paper or paperboard.

Groundwood pulp: Mechanical pulp produced by grinding pulpwood against a revolving grindstone in the presence of water.

Group selection: Method of harvesting in which small groups of merchantable trees are cut periodically. Natural regeneration is typically relied on to fill in the resulting gaps.

Growing stock: Classification of timber inventory that includes live trees of commercial species meeting specified standards of quality or vigor; cull trees are excluded. When associated with volume, includes only trees 5.0" in diameter at breast height (d.b.h.) and larger.

Hardwood: Technically, a dicotyledonous tree. Hardwoods typically have broad leaves and are often deciduous (they lose their leaves during winter); e.g., maple, oak, aspen, cherry and ash.

Harvesting: In this book, the process of felling trees for removal and use. More broadly, may also be used to include related activities, such as the skidding, processing, loading and transporting of forest products.

Hazardous air pollutant (HAP): One of 189 toxic substances as defined by the 1990 Clean Air Act amendments.

Headbox: Box at the head of a fourdrinier machine that regulates the flow of pulp to the machine wire.

Heat-set inks: Inks used in high-speed web offset printing. They set rapidly under heat and are quickly cooled.

Herbicide: One of a group of chemicals used to kill or suppress unwanted vegetation, usually hardwood competition or brush.

Hickies: Blemishes or irregularities on the surface of the paper sheet.

Holdout: Ability of paper or board to resist penetration by liquid substances, such as ink.

Hot-melt glues: Rapidly setting glue made from plastic, resin and waxes melted at 350ยบ F; frequently used to bind magazines and books. According to deinking experts, the most difficult contaminants to remove during deinking are the polymeric adhesives used as pressure sensitive adhesives and hot melt glues.

Hydrapulper: Large vat with an agitator used to hydrate and prepare pulp or recovered paper for papermaking or fiber cleaning and processing.

Hydrophilic: Affinity for water.

Hydrophobic: Aversion to water.

Ink holdout: Property of coated paper that allows ink to set on the surface with high gloss. If holdout is too high, it can cause set-off (transfer to the back of the previous sheet) in the paper pile.

Insecticide: One of a group of chemicals used to kill or control populations of unwanted insects.

Integrated: A mill that has facilities for producing both pulp and paper at the same site.

Intermittent stream: Watercourse that flows in a well-defined channel only in direct response to precipitation; such a stream is dry for a large part of the year.

Job lot: Paper unsuitable for a customer's desired end use and usually sold at a discount. The term is also used to describe press overruns or defective and off-spec papers that are still usable.

Kaolin : White clay primarily comprised of the mineral kaolinite; used as a filler and coating pigment for papermaking.

Kraft mill: Mill that produces kraft pulp.

Kraft paper: High-strength paper made from unbleached sulfate (kraft) pulp; usually brown in color.

Kraft pulp: Also called sulfate pulp. Chemical pulp made using an alkaline cooking process with sulfur compounds. This pulp can be bleached or unbleached and is noted for its strength.

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