Efficiency of water use is increasingly important for the paper based industry
Water is an essential element for paper and board production. Water acts as a bond between the fibres and in the production process, is needed for transporting, cleaning, lubrication, carrying energy in the form of steam and is used in cooling process units.
Water is usually taken from a nearby surface source such as a lake or river. 95% of the water used in the industry is cleaned and reused on site. All waste water is purified at the mill in accordance with European regulations and standards, before being returned to the environment. In 2012, the pulp and paper industries in CEPI membership returned 92.3% of surface and ground water to the environment, cleaner than before.
The main emissions to water from the pulp and paper making processes are COD, BOD and AOX. These are steadily reducing in Europe due to the use of better quality management and purifiers.
Mills have been working to reduce process water use for many years, as this makes good economic as well as environmental sense. The trend over the past two decades has been to reduce freshwater withdrawal by 20% in total volume.
CEPI (Confederation of European Paper Industries) has developed tools for member companies to measure their use of water. In 2012, the pulp and paper industry within CEPI member countries withdrew approximately 3.71 million cubic metres of water from surface and ground water sources of which 92.3% were returned to surface water supplies cleaner than before.
For further information: www.cepi-sustainability.eu
Assessment methodologies are under development including an ISO standard to ensure harmonised global rules.
As part of the debate, the Water Footprint Network defines a water footprint as “the total volume of freshwater that is used to produce the goods and services consumed by the individual or community or produced by the business”.
Water accounts distinguish between:
- withdrawals of water from rivers, lakes and aquifers (surface and ground water) that are used in industry (blue water)
- water from rainfall that is used to grow crops (green water)
- water which is an effluent from an industrial process (grey water)
Calculations of the “green water” footprint is of particular importance to paper based products as it relates to the interaction between the raw material from the forests and rainfall. The debate is ongoing about the scope of a “green” water footprint, but the view of CEPI (Confederation of European Paper Industries) is that a clear distinction should be made between the water balance of forests and the forest component of a water footprint of a paper based product.
A green water footprint component for a paper based product should reflect:
- the difference in water impact between an unmanaged forest (or a forest managed for other purposes) and a forest from which paper based products are sourced
- the share of the wood that is actually harvested and within that, the share of the harvested wood that is used for making paper based products. (The industry uses only small diameter trees and thinnings. Other users of the forest include the timber and biomass industries)
- the relevance of recycling of paper based products including cartonboard packaging. Fibres from cartons can be recycled 5 or 6 times without any bearing on the water in the forest
It is recognised that a water footprint is not like a carbon footprint. A water footprint is specific in time and place to the industrial process which is being measured. Indicators that only measure the volumes of water used are potentially misleading, as they may not accurately reflect impacts on the local environment. Thus a paper water footprint should clearly specify:
- the “blue” and “grey” components at mill level
- the net water impact of forests (“green” water)
Water Footprint of Cartons
The main parameters affecting the water footprint of a carton is the grade of cartonboard used and the type of ink selected.