Glossary

Activated sludge plant is an effluent treatment plant in which a large number of micro-organisms is maintained for oxidation of impurities dissolved into the effluent and their binding into solid form.

AOX (Adsorbable organic halogens) indicates total concentration of chlorine bound to organic compounds in waste water.

BAT (Best Available Techniques) mean the most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques for providing in principle the basis for emission limit values designed to prevent and, where that is not practicable, generally to reduce emissions and the impact on the environment as a whole. ‘Best’ means most effective in achieving a high general level of protection of the environment as a whole. ‘Available’ techniques are those developed on a scale which allows implementation in the relevant industrial sector, under economically and technically viable conditions, taking into consideration the costs and advantages, whether or not the techniques are used or produced inside the Member State in question, as long as they are reasonable accessible to the operator. ‘Techniques’ include both the technology used and the way in which the installation is designed, built, maintained, operated and decommissioned. (EU Council directive 96/61/EC concerning integrated pollution prevention and control)

Biological effluent treatment is a method of cleaning up waste water using living micro-organisms such as bacteria.

Black liquor is mixture of cooking chemicals and dissolved wood material remaining after sulphate pulp cooking. Black liquor is recovered during pulp washing, concentrated by evaporation and burned in the recovery boiler to regenerate the cooking chemicals and generate energy.

Bleaching is removal or modification of coloured components in pulp to improve brightness. Bleaching is carried out in several consecutive stages.

BOD₇ (biological oxygen demand) is a measure of the amount of oxygen needed by micro-organisms to break down solids and other readily degradable organic matter present in effluent in 7 days.

Brown stock stands for non-bleached pulp resulting in the pulp cooking phase.

Carbon dioxide (CO2) is gas produced in burning. Elevated levels of atmospheric carbon dioxide have been found to accelerate the greenhouse effect.

Carbon sink is a process that absorbs greenhouse gases from the atmosphere. The carbon sinks of the oceans and lands tie down about half of carbon dioxide emissions from human activities thereby slowing down climate change.

Caustic soda or sodium hydroxide (NaOH) is used as a pulp cooking and bleaching chemical.

Causticising is a process by which green liquor separated from the smelt produced in the recovery boiler is converted to white liquor with the help of quicklime, thus allowing the cooking chemicals to be re-used.

Chips are wood chips produced by a chipper; used as raw material in pulp cooking.

Chlorine dioxide (ClO2) replaces elemental chlorine in ECF bleaching.

Chlorine free see  TCF

CODCr (chemical oxygen demand) is the amount of oxygen consumed in complete chemical oxidation of matter present in effluent. It indicates oxygen consumption by slowly degradable organic matter present in effluent.

Delignification is the removal in pulpmaking of lignin, the material that binds wood fibres together.

ECF (Elemental chlorine free) bleaching uses chlorine dioxide, thereby avoiding the use of elemental chlorine.

Electrostatic precipitator is used to clean up flue and process gases. It removes 99.5-99.8% of dust particles emitted from recovery boilers, lime kilns and bark-fired boilers.

EMAS (Eco-Management and Audit Scheme) is the European Union’s  environment management and auditing system for industrial companies. EMAS registration is voluntary.

Eutrophication stands for increased growth of fauna. In waterways it is manifest as turbidity, increased growth of aquatic plants and as excessive growth of plankton algae  and filamentous algae in shore areas.

Evaporation plant is the pulp mill department where spent cooking liquor is concentrated to make it suitable for burning and chemicals recovery.

Fourdrinier part is located at the front end of a pulp mill’s desiccating machine. It is composed of Fourdrinier wire, which is a levelled plastic or metal tissue, and of suction and press rolls which are used to extract water from pulp.

Generator produces electricity by transforming kinetic energy generated by turbine into electric energy.

Greenhouse effect means the effect of greenhouse gases in the atmosphere. They allow short wavelength solar radiation to reach the Earth but retain radiation of longer wavelength, which causes warming of the atmosphere. Water vapour, carbon dioxide, methane and nitric oxide are the main greenhouse gases.

Green liquor is produced by means of dissolving the cooking chemicals digested in the recovery boiler. It is regenerated into white liquor by using lime. White liquor is a cooking solution of pulp.

Hemicellulose is a carbohydrate which in addition to cellulose and lignin is the most important components of timber.

Hydroxen peroxide is used in bleaching TCF pulp.

Integrate refers to a mill unit where a pulp mill is situated next door to pulp processing industrial unit / plant. Many of the advantages of sulphate process can be best utilised in an integrate.

ISO 14001 is the International Standardisation Organisation’s standard for environmental management systems.

Lignin is a polyphenolic amorphous polymer which binds wood fibres together in the tree and imparts rigidity and brown colour.

Lime kiln is used to reburn lime sludge (CaCO3) to form calcium oxide (CaO), which can is reused in causticising.

Lime sludge (CaCO3) is calcium carbonate in solid form, and it is formed in manufacture of white liquor and is extracted from white liquor by means of evaporation.

Liner is packaging board used as a surface layer on corrugated board.

Long-fibre pulp is made of coniferous timber.

Malodorous gases include various sulphur compounds, small amounts of which are formed in sulphate pulp process. The compounds cause the smell characteristic to a pulp mill. Malodorous gases are recovered as comprehensively as is possible, and are disposed of by means of burning.

N stands for nitrogen which is the main constituent of air (about 80%). Nitrogen arriving in waters airborne, bound in wood raw material or in chemical compounds causes eutrophication.

NOx is collective symbol for nitrogen oxides; produced partly during combustion and partly by reaction between oxygen and nitrogen in the atmosphere. Nitrogen oxides are present in flue gases and vehicle exhaust gases. They form acids and nutrient compounds causing eutrophication

Nutrients is a general term for phosphorous and nitrogen which for example algae can utilise. Nutrients cause eutrophication of waterways.

Oxygen delignification, or oxygen bleaching is a stage in pulpmaking during which the lignin content of pulp is reduced by means of oxygen gas (O2) in an alkaline environment.

Ozone (O3) is an allotrope of oxygen that is generated out of oxygen during electrical discharges. Ozone in the upper atmosphere protects the earth against harmful ultraviolet radiation from the sun.

P stands for phosphorus, a nutrient causing eutrophication in receiving waters. In the forest industry phosphorus mainly originates in wood raw material.

PEFC certification is a certification system initiated by European private forest owners and promotes sustainable forestry.

Recovery boiler is used to burn black liquor from sulphate pulping for recovery of inorganic chemicals as well as for energy production.

Reinforcement pulp is strong long-fibre pulp utilised to provide strength in printing papers containing groundwood pulp or recycled fibres.

Schal board refers to board removed from the outmost part of a log. Schal boards are chipped at saw mills and used as raw material of pulp.

Screening stands for the cleaning of pulp of foreign substances.

Short-fibre pulp is made of deciduous tree / hardwood.

Sulphur dioxide (SO2) is a gas produced by burning sulphur-containing fuels and as a by-product in chemical pulping. Reacts with oxygen and water vapour in the air to produce sulphuric and sulphurous acids, which dissolve in rain, causing acidification of soil and water.

Sulphate pulp is chemical pulp produced by cooking wood in a liquor containing sodium hydroxide and sodium sulphide.

Tear strength is an established indicator of pulp strength.

Tensile strength is an established indicator of pulp strength.

Totally chlorine-free (TCF) is pulp bleached entirely without chlorine chemicals.

Turbine is a part of the power station receiving energy for rotation from steam produced in boilers. The turbine, on its part,  rotates the electricity producing generator.

White liquor is a compound consisting of caustic soda (NaOH) and sodium sulphate (Na2S), and it is used as cooking solution of sulphate pulp.