Environmental Management: Principles and practice


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Domestic refuse
Refuse (trash or garbage) disposal can be based on self-help, which cuts the cost and
may benefit poor people. Such an approach includes street corner skips which are
collected and taken to the tip or recycling plant by a rota of local people. An alternative
is to offer an incentive to people to collect waste and bring it to a recycling plant,
composter or incinerator. Recycling waste can provide employment, and local
authorities or aid agencies could assist by providing protective clothing, supervision,
healthcare and refuse handling and processing equipment (where informal and less
healthy garbage picking would probably develop anyway).
Cities generate large quantities of refuse: in developed countries this can be
500 to 800 tonnes per day per million people. This may be landfilled, incinerated,
dumped at sea, recycled or composted. Domestic waste is a mixture: in the UK it is
typically (approximately): 7 per cent plastics; 8 per cent metals; 10 per cent glass; 10
per cent fines (dust); 12 per cent miscellaneous textiles; 20 per cent waste food and
other easily decomposed material; and 33 per cent paper products (The Times 14
June 1993:32). The trend in developed countries has been towards a greater proportion
of packaging materials, much of it non-degradable plastics and metal foil, and a
decline in the use of reusable glass bottles since the 1960s, matched by an increase
in plastic disposable bottles. This mixture can make sorting and treatment a problem.
Tin and steel can be recovered with magnets, and aluminium cans are fairly easy to
recycle, but plastics are more of a challenge.
In developing countries refuse is likely to contain less packaging and more
organic matter, so it may be easier to compost or generate methane from, but more
difficult to compress or incinerate.
Over 90 per cent of UK refuse was disposed of by landfill in the mid-1990s
(North, 1995:164); at the same time in the USA over 70 per cent was similarly disposed
of. Landfill sites should be located to avoid nuisance and the risk of contaminating
streams or groundwater: a minimum of a layer of clay should be put in place before
tipping, and after completion used to cap and seal the tip (Figure 11.1). Many
redundant tips and some of those at present in use meet none of those standards and
present a serious future hazard because they are poorly sealed. Sometimes domestic
refuse is mixed with industrial wastes (co-disposal), power-station flue-ash or sewage


POLLUTION AND WASTE MANAGEMENT
213
for convenience or in the hope that it will assist breakdown of harmful materials.
Whether it is wise is debated.
It is important to locate landfill sites to avoid nuisance to surrounding areas, to
reduce the risk of ground and surface water contamination, to minimize damage
from escaping methane or underground fires, and to ensure that vermin are not a
problem. Houseflies and rodents can cause difficulties some distance from landfill
sites if they are allowed to breed, and scavenging birds may pose a serious threat to
airports within a few miles (Clark et al., 1992).
Provided that decomposition of organic matter is vigorous, a refuse tip
should generate enough heat to kill most harmful organisms. However, ‘tip
archaeology’ in the USA suggests that paper products may be a major source of
contamination of groundwater, streams and surrounding environments because
of the printing inks, waxes and sealants used on them. Landfill generates methane,
which presents an explosion and fire risk for decades after tipping. Methane,
heat from spontaneous combustion, toxic compounds and subsidence limit the
future land use of tip sites, although in some cases the gas can be collected and
used for power generation or combined heat and power (biotechnology might
improve methane production). (For an objective discussion of waste disposal
and recycling see North, 1995:164–186.)
Plastic waste is a problem in landfill, as litter on land and adrift in the oceans.
Some plastics degrade slowly and can cause considerable harm to wildlife (for
FIGURE 11.1 Landfill refuse disposal site in Belgium. This is a state-of-the-art facility with
geosynthetic clay and high-density polyethylene lining to prevent leaching. Each pit can hold
ca. 250,000 tonnes of waste. The gas generated during decomposition will be captured for
electricity generation
Source: Press release photo from Bitumar N.V. Belgium, 1998


CHAPTER ELEVEN
214
example marine turtles are injured by eating floating polythene bags) and equipment
like pumps. Phantom fishing—lost or discarded plastic nets and long-lines—do
tremendous damage to wildlife. This might be reduced if biodegradability could be
built in. Unfortunately, fishermen do not want equipment to deteriorate before it is
lost. What is needed are degradable plastics which quickly rot once lost or discarded.
There has been some progress, and laws in the USA, Sweden and Italy insist on
biodegradable plastics for certain types of packaging.
Germany requires manufacturers to arrange for proper disposal of the packaging
materials around their products, and The Netherlands has a covenant with
manufacturers which aims to reduce and simplify packaging to aid recycling. About
60 per cent of the world’s shipping should be covered by a 1989 treaty requiring no
dumping of plastics at sea (Annex V of the International Convention for the Prevention
of Pollution from Ships). However, a glance at any strandline confirms that compliance
is lax, and much plastic also gets into the sea from rivers and sewers.

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