Environmental Concerns in the Paper Making Process
Wood pulp is an important product used in the paper making process.
Yet, it wasn't used in the process until around 1850 when a German
by the name of Friedrich Gottlob Keller experimented with crushing
wood with a wet grindstone in order to obtain wood pulp. This was
done largely out of necessity, as the fiber crops that were previously
used for the process were experiencing a shortage.
After Keller successfully crushed wood to create pulp, C.B. Tilghman,
who was an American chemist, and C.F. Dahl, who was a Swedish inventor,
experimented with using chemicals to break the fibers down. The
ability to use wood pulp, coupled with the invention of the steam
powered printing and paper making machines, made the process of
paper making far less expensive. While the greater availability
of paper helped improve literacy as more books could be inexpensively
produced, the use of wood pulp to create paper has led to a number
of environmental concerns.
Forest Reduction
Forest reduction is one of the number one concerns facing the paper
and pulp industry. The exact number of trees needed to produce
paper depends on the process used to create the pulp. The groundwood
process results in more pulp and produces more paper than the Kraft
process, but the Kraft process creates paper of a higher quality.
By most estimates, it takes approximately twenty-four 40 foot softwood
and hardwood trees of six to eight inches in diameter to produce
a ton of writing and printing paper when the Kraft process is used.
Under the assumption that the groundwood process is twice as efficient,
it would take about twelve of these same trees to create a ton of
newsprint.
In response to this environmental concern, most paper and pulp
factories plant new trees to replace the ones they cut down
for their paper making business. Of course, it takes several years
for these newly planted trees to reach the same size as the trees
they are replacing. Paper recycling has also helped reduce the number
of trees needing to be harvested for paper, as a typical piece of
paper made from wood pulp can be recycled four to seven times before
the fibers become too short to reuse. To maintain the quality of
recycled paper, it is usually mixed with virgin pulp wood.
Waste By-Products
The waste by-products created from the paper making process is
another concern. Chlorine, for example, has long been used to bleach
the pulp in order to create the desired white paper. When this is
done, chlorinated byproducts such as furans and dioxins are produced.
In British Columbia, some fisheries were forced to close in 1992
as the result of these contaminates. Fortunately, technology has
advanced to the point that the use of chlorine in the bleaching
process has either been eliminated or substantially reduced.
Wastewater effluent has also caused environmental concerns because
it contains high biological oxygen demand, lignins from the trees,
and dissolved organic carbon, as well as heavy metals, alcohols,
chelating agents, and chlorates. In order to reduce the impact of
the wastewater effluent, less detrimental agents are utilized in
the pulping process and much of the effluent is recycled.
Another byproduct of papermaking is black liquor, which is created
when the Kraft process is used for breaking down the wood chips
used to make the paper. Black liquor also contains lignin from the
trees. The concentration, however, is weak. Nonetheless, the paper
industry has found a way to decrease the environmental impact of
this liquid as well as to make the process of paper making more
efficient by evaporating the water from the black liquor. After
undergoing a boiling process, it is changed into what is know as
green liquor and combined with lime to form white liquor. This white
liquor is then reused in the pulping process.
Like most industries, there are environmental concerns associated
with the paper making process.
Fortunately, the paper mills are working hard to find ways to ensure
the environment is harmed as little as possible.
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