Page 31 - Solid Waste Analysis and Minimization a Systems Approach

THE HIERARCHY OF SOLID WASTE MANAGEMENT 9

1.3 The Hierarchy of Solid Waste

Management

When approaching solid waste analysis and minimization, there is an accepted hierarchy,
or order of solution approaches, that should be deployed when analyzing an organization’s
waste streams. This hierarchy is given before a discussion of definitions of solid waste man-
agement terms because it makes the definitions more meaningful and easier to understand.
This hierarchy has been defined in the Pollution Prevention Act of 1990 as follows:

“The Congress hereby declares it to be national policy of the United States that pollu-
tion should be prevented or reduced at the source whenever feasible; pollution that
cannot be prevented should be recycled in an environmentally safe manner, whenever
feasible; pollution that cannot be prevented or recycled should be treated in an envi-
ronmentally safe manner whenever feasible; and disposal or release into the environ-
ment should be employed only as a last resort and should be conducted in an
environmentally safe manner”

Based on that definition, the solid waste management solutions, in order of prefer-
ence are

1 Source reduction
2 In-process recycling
3 On-site recycling
4 Off-site recycling
5 Waste treatment to render the waste less hazardous
6 Secure disposal
7 Direct release to the environment

These terms may be easier to understand with an example. A very straightforward
and simple example involves a company that receives incoming raw material in card-
board packaging. Suppose the company is a metal stamping plant for the automobile
industry. Below are situations where the company could apply the hierarchy:

1 Source reduction. Eliminate the waste through engineering process modifications. For
example, the company could work with the vendor to eliminate the use of cardboard
containers and switch to returnable plastic containers. This is the most preferred method
and completely eliminates the problem of waste management and need for recycling.
2 In-process recycling. If waste is generated, develop a separation method to use the
waste as a raw material for the same process. For example, the company could col-
lect the metal scrap from the stamping process and attempt to process it again in the
same process.
3 On-site recycling. If waste is generated, develop a separation method to use the
waste as a raw material for another in-house process. For example, the company could
use the cardboard packages to ship their own final products.