Geography Reference
In-Depth Information
York. Many other cities throughout the world followed these examples. But burning
rubbish led to complaints about an increase in ash from the smoke stacks falling on
neighbouring communities as well as noxious fumes. In the mid-twentieth century
it was discovered that dioxins, a major health hazard, were also produced. This led
most cities in the developed world to abandon their burning of waste. It seemed less
hazardous, as well as easier and cheaper, in most areas to simply bury the waste in
what started out as inexpensive landfills , grassing them over when filled. However
most urban areas have run into the problem of a lack of space for new dumps, which
has led many to pay to simply export their rubbish to other areas where landfills are
cheaper, or increasingly to incinerators in other countries. It was also soon realized
that landfills also generated noxious by-products, especially methane from the rot-
ting garbage, which created its own health hazard. Indeed almost 20 % of the U.S.'s
methane comes from landfills (EPA 2013 ). Increasingly many cities are develop-
ing methane recovery systems by boring holes into the dumps to collect the gases,
which are then used to generate electricity, rather than letting it add to greenhouse
gas build-up.
The scarcity of local land for new landfills and increasing concerns about sus-
tainability led to new waste treatment solutions from the 1990s. Most cities in the
developed world started to adopt multiple-separation approaches to reduce the
amount of waste being buried, by recycling different parts of the garbage stream.
Instead of collecting unsorted garbage, many municipalities get households to sep-
arate waste into different categories, such as the threefold division into: general
garbage; those products that can be recycled—such as glass, metal packaging, pa-
per, cardboard and plastics, and organic waste. The degree to which this separation
occurs varies by city and country. However, the collection of these different types
of waste, as well as building waste, either by municipal workers or private contrac-
tors, is increasingly from purpose-built containers; many cities now have two or
three separate household waste bins, or distinctive coloured plastic bags for differ-
ent types of waste, and sometimes sequential pick-up days for the different waste
products. General garbage is still mainly dumped into landfills; but more and more
cities, at least in the developed world, collect, sort and re-cycle as much glass, paper
and plastic products as possible. Organic waste is often collected separately and
often reprocessed to be used as compost fertilizer and sent to local farms to increase
their productivity—reducing the need for imported fertilizer as a result—or used to
generate biogas which can be fed into the city's gas supply or used to power local
buses. Cities have been to the fore in these policies. For example, an early example
of this latter approach occurred in Helsinborg in Sweden which converted all of its
buses to run on this fuel. Other cities encourage consumers to take various types of
waste to particular disposal locations, such as in large shopping centre parking lots,
where different bins are available for different products. Increasingly, however, spe-
cialized waste centres for specific types of waste have been provided, such as those
for medical waste, paints and especially for electronic devices, where the valuable
metals found in these products can be extracted and re-used, instead of just being
dumped into landfills. Seasonal waste centres have also been created, such as leaf
depots in autumn, where dead leaves can be collected and later composted, usually
by the municipality.
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