Problems of Paper Recycling in Western Europe: Part 8

To meet the physical property demands of the actual products and their manufacture, there are several ways of modifying and furnishing of the base paper or board. Normally, recycled fibers have partly lost the properties of primary fibers. For example, re-pulping causes fibers to shorten, which, in turn, implies reduced strength and moisture properties. Depending on the average age of the recycled fibers used in the furnish, the thickness of the base paper or board has to be increased to maintain the required strength and scoring level. Alternatively, undersized fibers could be screened out of the stock; however, because other fiber properties are also involved (such as strength, scoring, and folding), screening alone would not necessarily guarantee the adequate properties. It would also mean less yield of fibers though the most aged material is always screened away or dissolved. The common solution to the problem is to add primary fibers to the furnish by either mixing them with reused fibers or assembling the paper as layers of different qualities of fibers. The specific weight of papers in the cases where recycled fiber is used tends to be 5% to 15% higher than in the cases where only primary fibers are used.

The environmental impact of recycling on greenhouse-gas emissions is an important issue to be considered. What are the consequences if wood balances (the yearly increment in relation to the yearly harvest of wood) become largely positive? How do greenhouse-gas emissions from the natural cycle of the surplus wood compare with emissions from incineration? These questions could not be studied completely in the current feasibility study but are to be evaluated in the planned full-scale study.