Page 47 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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widely used due to its low cost and good fabric quality. Sodium sulphate and
sodium dichromate are both used in this process. They are toxic and haz-
ardous chemicals. In addition they are dangerous to worker’s health during
handling and storage. The cleaner production opportunity assessment rec-
ommends substituting sodium sulphate with glucose and sodium dichromate
with sodium perborate based on economical, technical and environmental
feasibility. The new materials are safer to the environment and public health.
They also improve the quality of fabric and the process’s productivity.

On-site recycling: This involves returning the waste material either to the
original process or to another process as input material (inside the same fac-
tory). In other words, on-site recycling means re-entering the waste into the
process as a substitute for an input material or sent as useful byproducts or
raw material for other processes within the same factory. For example, in
the pulp and paper industry, fiber recovery from white paper, surplus pulp
fiber, paper mill offcuts and damaged paper rolls are recycled into the pulp-
ing process. Another example, in the oil and soap industry the gravity oil
separator (GOS) will separate the oil from the industrial wastewater stream
and return it to the industrial process as explained above.
On-site recycling could be planned for and implemented through sim-
ple processes that might include equipment modifications and/or better
process control in order to ensure that waste could be safely used as byprod-
ucts for the same industry with the required specifications.

Off-site recycling: This implies that the recycling process is done by another
party that recycles the industrial wastes or at the post-consumer stage such
as municipal solid waste. There are companies specialized in recycling the
specific wastes. They buy certain types of waste, recycle them then sell them
to other industries. All municipal solid waste recycling, which is explained
in detail in Chapters 5 and 6, is considered off-site recycling.
Product modification: This is oriented towards change in the product design
to use less raw material or energy or to minimize emissions. For example,
reducing the metal content of soft drink cans by changing their design and
the material from steel to aluminum. This change in can design made it
lighter to handle and used less material to manufacture. Another example is
a paper mills using unbleached toilet tissues instead of white tissue to save
raw material and chemicals.
This product modification change is used to reduce not only waste gener-
ated but also materials consumed. Also, changing the design of the product such
that it requires fewer packaging materials is considered within this category.
One element of sustainable development that is extremely important is the
change in attitudes concerning the way development and the environment are
seen. There are many prerequisites that must be fulfilled so that sustainable
development can be practiced correctly. There must be willingness to try