Page 429 - Academic Press Encyclopedia of Physical Science and Technology 3rd Chemical Engineering
P. 429
P1: GLQ/GUB P2: GQT Final Pages
Encyclopedia of Physical Science and Technology EN012I-591 July 26, 2001 15:54
Pollution Prevention from Chemical Processes 595
companies and whole industry associations or sectors, the
policy of priority for pollution prevention took shape in
the United States. The outcome has been impressive, not
necessarily uniform, but achieving a philosophical shift
to cleaner manufacturing. These events are even more im-
pressive when it is recognized that virtually all of the indi-
vidual changes to manufacturing have been cost-effective
(a generally held rule of a 2-year payback on capital
investment).
Use of the term pollution prevention is common in the
United States, but is actually one of many nearly synony-
mous terms, which include the following:
Waste minimization
Cleaner production
Waste reduction
Clean technology
Source reduction
FIGURE 2 Plant with pollution.
Environmentally benign synthesis
Environmentally conscious manufacturing
Green chemistry materials to make the saleable products(s) and energy. The
Technology for a sustainable environment only significant outputs are saleable products.
Sustainability
Green engineering
IV. HOW DOES ONE DEFINE
Use of a particular terminology usually is linked to the POLLUTION PREVENTION?
forum in which the debate is occurring and hence these
terms have subtle differences, but share the major empha- We define pollution prevention fairly broadly, in keeping
sis on prevention. That is, all of these descriptors refer to with the actual practices widely utilized by industry. This
the intuitive perspective that it is advantageous to manage definition is any cost-effect technique aimed at reducing
chemical losses or wastes generated from the top of a hier- chemical or energy-related emissions that would subse-
archy for waste minimization. In addition, there is a certain quently have to be treated. In keeping with the generally
trend to reinvent terms with new government initiatives. voluntary nature of U.S. pollution prevention activities,
the double hurdle of technical and economic feasibility
are met in a pollution prevention option (Fig. 4).
III. WASTE AS POLLUTION This definition manifests itself in the form of the pollu-
tionpreventionhierarchyshowninFig.5.Inthishierarchy,
An industrial waste is defined as an unwanted by-product safe disposal forms the base of the pyramid, and minimiz-
or damaged, defective, or superfluous material of a manu- ing the generation of waste at the source is at the peak.
facturing process. Most often, it has or is perceived to have The U.S. Environmental Protection Agency (EPA) def-
no value. It may or may not be harmful or toxic if released inition of pollution prevention recognizes actions which
to the environment. Pollution is any release of waste to encompass the upper three levels in the hierarchy: min-
the environment (i.e., any routine or accidental emission, imize generation to segregate and reuse. The U.S. EPA
effluent, spill, discharge, or disposal to the air, land, or
water) that contaminates or degrades the environment.
Figure 2 depicts a typical manufacturing facility. In-
puts to the facility include raw materials to produce the
saleable product(s), water, air, solvents, catalysts, energy,
etc. Outputs from the facility are the saleable product(s),
waste energy, and gaseous, liquid, water, and solid wastes.
In contrast, a manufacturing facility with an absolute min-
imum (but not zero) amount of waste being generated is
shown in Fig. 3. Inputs to the facility include only the raw FIGURE 3 Absolute minimum waste generation facility.