Page 337 - Synthetic Fuels Handbook

CHAPTER 11

FUELS FROM DOMESTIC
AND INDUSTRIAL WASTE

Waste is the remains or by-product from a process for which no use is planned or foreseen.
The words domestic (or municipal) and industrial are qualifiers of the source of the waste
and, to some extent, also descriptive of the contents of the waste. Once a material has been
designated as waste, it remains waste until it has been fully recovered and no longer poses
a potential threat to the environment.
Thus, domestic waste (also known as rubbish, garbage, trash, or junk) is unwanted
or undesired material (although the old adage one man’s waste is another man’s treasure
sometimes applies). Waste is the general term; though the other terms are used loosely as
synonyms, they have more specific meanings: rubbish or trash are mixed household waste
including paper and packaging; food waste or garbage (North America) is kitchen and table
waste; and junk or scrap is metallic or industrial material (Table 11.1). There are other cat-
egories of waste as well: sewage, ash, manure, and plant materials from garden operations,
including grass cuttings, fallen leaves, and pruned branches.
On the other hand, industrial waste is waste type produced by industrial factories, mills,
and mines. It has existed since the outset of the industrial revolution. Toxic waste and
chemical waste are two more specific designations of industrial waste.
Municipal solid waste (MSW) is a waste type that includes predominantly household
waste (domestic waste) with sometimes the addition of commercial wastes collected by a
municipality within a given area. They are in either solid or semisolid form and generally
exclude industrial hazardous wastes. The term residual waste relates to waste left from house-
hold sources containing materials that have not been separated out or sent for reprocessing.
There are five broad categories of municipal solid waste: (a) biodegradable waste such
as food and kitchen waste, green waste, paper—which can also be recycled; (b) recyclable
material such as paper, glass, bottles, cans, metals, and certain plastics; (c) inert waste
such as construction and demolition waste, dirt, rocks, debris; (d) composite wastes which
include waste clothing and waste plastics such as toys; and (e) domestic hazardous waste
(also called household hazardous waste) and toxic waste such as discarded medications,
paints, chemicals, light bulbs, fluorescent tubes, spray cans, fertilizer and pesticide contain-
ers, batteries, and shoe polish.
Some components of waste can be recycled once recovered from the waste stream, for
example, plastic bottles, metals, glass, or paper. The biodegradable component of wastes
(e.g., paper and food waste) can be composted or anaerobically digested (Chap. 9) to produce
soil improvers and renewable fuels. If it is not dealt with in a sustainable manner biodegrad-
able waste can contribute to greenhouse gas emissions and by implication climate change.
On the other hand, there is also electronic waste which is a waste consisting of any
broken or unwanted electrical or electronic appliance. While there is no generally accepted
definition of electronic waste, in most cases electronic waste consists of electronic prod-
ucts that were used for data processing, telecommunications, or entertainment in private
households and businesses that are now considered obsolete, broken, irreparable, or of no

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