Page 103 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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TABLE 2.34
Cost/Benefit Analysis
Pollution prevention process Economic and environment Payback period
savings and benefits
Process modification: • Material consumption Payback period:
Implement alternatives reduction: 15% 1 year
to conventional spray • Waste volume from
gun systems spray booth cleanup
reduction: 50%
Reuse: Flush equipment • Waste savings/ Payback period:
first with dirty solvent reduction: 98% 1 year
before final cleaning with • Solvents reduction:
virgin solvent and use 98.4%
cleanup solvents in
formulation of paint

– Routine maintenance of spray gun equipment can prevent equip-
ment from breaking down and leaking.
– Allocate a designated area for chemicals. It is also recommended to
have a simple measuring device to determine exactly the amount
of chemicals to be mixed and assure a homogeneous mixing.

Table 2.34 represents a sample of the economic savings gained and the pay-
back period from implementing cleaner production techniques.

Iron and steel sector: Wire rods factory
This case study revolves around a Chinese manufacturing company. The case
involves a factory that specializes in wire rods. The factory is located in Beijing,
China, and consists of 700 employees. The factory imported two wire mills
with the capacity to produce 700,000 tons of wire rods annually. The mill
was listed as one of the worst polluters in China, and a project was assigned
for cleaner production in 1989. In order to comprehend the case study, one
must be acquainted with the manufacturing steps. First of all, the raw mate-
rials are obtained in the form of billets where they are transported into a fur-
nace for melting in order to shape the metal. After heating the billets to a
high temperature the metal is then rolled into a coil shape of diameter 6.5–10
microns. The coil is then cooled and collected in order to be compacted and
packaged for delivery.
An in-depth look at these manufacturing steps reveals the amount of
energy used and the emissions from the heating process of the metal. The report
from the factory showed that “450 tons of waste lubricates were generated from
the cooling process of the coils, while 350 tons of waste hydrodynamic oils were
produced from collecting and packing the coil” (Cleaner Production in