Paper-Recycling System: Part 12

Continuous increased large-scale recycling can also introduce fiber-aging problems with changed distributions of the ages and a higher proportion of older fibers. At present, this is not a problem due to a relatively low overall recycling rate; it is possible to fulfill the demand for recycled waste paper with such papers that are, in practice, entirely based on primary fiber (newsprint, printing and writing, primary linear board, and so on). There is no need for or even the possibility of collecting papers containing recycled fiber such as sanitary papers and low-grade shoe boxes for recycling. Consequently, today's recycling is predominantly based on reusing paper fibers only once. Assuming, for example, that 70% of recycled fiber is used for all papers and boards continuously, in the long run, more than 20% of the fiber employed for recovery would be used more than 5 times and about 5% more than 10 times. However, depending on the paper grade, a fiber can be reused only 3 to 5 times before it fragments or dissolves. This means that all of the fiber collected for recycling cannot be utilized in a closed, stationary recycling system. Due to technical and physical limitations the overaged part of fibers needs to be extracted in re-pulping to maintain the continuity of paper production.