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102 Membranes for lndustrial Wastewater Recovery and Re-use

3.2 The pulp and paper industry

3.2.7 lntrodoction
Pulp and paper production in the world is localised in countries with natural
forest resources (Figs. 3.16 and 3.17). Thus most paper products are
manufactured in the USA, Canada, China, Europe, Korea and Brazil. In spite of
the growing popularity of the internet and electronic journals, global pulp and
paper production is steadily increasing at the same rate as gross domestic
product in the world. In 1998 the world production of pulp and paper was
estimated to exceed 300 million tonnes for the first time.
The pulp used for paper products is either chemical or mechanical pulp, or
recovered paper. The paper products, in which the different pulps are used in
varying proportions, can be divided in the following paper grade groups (Zippel,
2001):

0 Newsprint
0 Fine paper (“wood-free paper”)
0 Magazine paper (“wood-containing paper”)
0 Tissue
0 Packaging paper (liner and fluting)
0 Multiply board

In addition to different pulps, different fillers and/or coating materials, such as
pigments, are used. A survey of 100 German paper mills showed that the raw
materials in papermaking were (Zippel, 2001):

0 Chemical pulp - 2 1%
0 Mechanical pulp - 14%
0 Recovered paper - 43%
0 Filler, pigments - 16%
0 Water - 6%
The proportions, however, vary depending on the location of the paper mill
and on the paper grade produced.
Even though water constitutes only 6% of the raw materials used in paper
making, its importance is significantly enhanced by its role as a carrier of raw
materials through the paper making process before the paper machine drying
section. The water quality has a direct effect on process operability and product
quality.
The specific freshwater consumption for the pulp and paper industry is defined
as the amount of freshwater used for the manufacturing process, taken from
external sources, related to the air-dry net weight material produced as finished
or intermediate rolls. During the twentieth century the specific fresh water
consumption has fallen dramatically from around 300 m3/t (i.e. m3 per tonne) at