Page 156 - Design for Environment A Guide to Sustainable Product Development

Design Rules and Guidelines 135

even when production flow remains constant, it is possible to reduce
the volume of harmful waste generated by modifying the product or
the production process. As discussed in Chapter 3, the introduction
of disclosure requirements and publication of the EPA Toxic and Haz-
ardous Release Inventory (TRI) has been instrumental in motivating
manufacturers to reduce such releases voluntarily. The guidelines
below focus on reducing total releases, but another viable strategy is
to convert toxic or hazardous wastes into valuable by-products (see
Section C, Design for Revalorization).
Toxic and Hazardous Substance Removal
Removal of toxic or hazardous substances from pollution and waste
streams is the traditional method for limiting human exposure and
environmental dispersion. Manufacturing facilities may routinely
release a variety of toxic or hazardous substances to the environment
via stack emissions, fugitive emissions, wastewater discharges, and
solid or hazardous waste disposal. Additional environmental con-
cerns include ozone-depleting chemicals, such as perfluorocarbons,
and greenhouse gas emissions (see Section D.2, Design for Natural
Capital). Airborne emissions may be partially removed through
pollution control devices, such as oxidizers, scrubbers, filters, or
electrostatic precipitators. Liquid and solid wastes may be treated
or disposed of on-site, sent to a municipal waste treatment facility, or
transferred to a waste management contractor.
While requirements for control of workplace and environmental
releases are typically regulated, there are many companies that
choose to go “beyond compliance” and further limit releases in order
to reduce potential liabilities or to anticipate more stringent regula-
tions. In some cases, companies have requested that their suppliers
adopt similar stringent measures if the regulations in their home
country are more lax. The objective of these practices is to reduce the
potential for chronic exposure to substances that may cause illness to
plant workers, neighboring residents, or wildlife.

Process Emission and Waste Reduction
The largest source of toxic and hazardous substance releases is typi-
cally in manufacturing processes that involve physical or chemical
transformations, as opposed to assembly of components. Process
emissions and wastes can be broadly separated into internal releases
within the production facility, which influence occupational expo-
sures, and external releases to the environment. Examples of guide-
lines for process waste reduction include

• Reduce process throughput—the flow of materials through
the supply chain can be reduced by identifying and minimiz-
ing non-product output; for example, by recycling pallets,
solvents, catalysts, scrap materials, or process water.