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< prev - next > Waste management Managing organic municipal waste (Printable PDF)
MANAGING ORGANIC
MUNICIPAL WASTE
Introduction
Organic waste often forms as much as 75% of
household waste generated in developing
countries, compared with just 30% in
industrialised countries. In many cities in
developing countries, per capita waste generation
rates are in the order of 500g/day, some 300g of
which may be organic. Thus a city of 1 million
population may produce 300 tonnes of organic
waste daily. Organic waste is a major issue!
This technical brief begins by describing the
characteristics of organic waste, its sources and
the particular hazards, challenges and
opportunities it presents. It goes on to present a
number of options for processing organic waste,
including use as animal feed, biogas digesting,
and composting. Many composting techniques are
simple, and compost is relatively easy to make.
However, sourcing uncontaminated raw materials,
making a high-quality product, and making
composting viable, can be difficult. This technical
brief discusses some of the challenges and how to
overcome them.
This brief would be useful for anyone facing the
challenge of managing organic waste. It is
particularly intended for project engineers,
planners or managers in municipalities, NGOs and
businesses.
Figure 1: Composting in Colquencha,
Bolivia.
Photo: Alfredo Quezada / Practical Action
Organic waste
Organic waste in towns and cities is generated by households, businesses, industries and
local authorities. It consists of kitchen waste (e.g. potato peelings), waste food (e,g, leftovers
in restaurants, spoiled fruit and vegetables from markets), garden waste (e.g. grass clippings
and hedge trimmings) and industrial waste (e.g. from agricultural and food processing
factories). Of course agriculture produces vast quantities of organic waste such as rice husk,
straw and manure. However, this rarely becomes mixed with domestic or commercial organic
waste so is not discussed in this brief. In addition, most farmers compost it themselves, as
do many urban and peri-urban nurseries.
Unlike other components of household waste such as metals, glass and paper, organic waste
is considered low-value and is rarely collected from recycling or processing by the informal
sector or businesses. This can be explained by its density (it is composed predominantly of
water), the cost and difficulty of transportation, the land required for processing, and the
relatively low-value of resultant products.
Particularly in warm climates organic waste tends to begin decomposing quickly -- within a
day or so. Rotting organic waste is often responsible for the foul smell in bins, vehicles and
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