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Abstract
The world-wide intensification of livestock industries
poses major challenges for waste
disposal. For example, the total solids wastes
discharged from livestock farms in China exceeded
1.7 billion tons in 1997, with a further
20 billion tons of waste water being discharged
to the environment — only 10% of
these wastes were treated!
A key element of sustainable development is
Cleaner Production. Cleaner Production is an
approach in which wastes are handled in such
a way that environmental pollution is avoided.
Cleaner Production practices include waste
minimisation, pollution prevention, recycling
and community-based environmental approaches.
An increase in the production of livestock
products means an increase in the production
of livestock wastes and, consequently, an increase
in the potential for environmental pollution.
The applications of the principles of Cleaner
Production for four types of livestock waste
are discussed in this paper.
With wool-scouring wastes, the process
streams are segregated in order to separate
the raw wool contaminants so that the dirt and
wool wax can either be composted to produce
either a soil conditioner or a premium potting
mix, or used as a fuel. The water-soluble contaminants
can then be used as a source of
potassium. The treated water can be recycled
to the washing process, thereby eliminating
aqueous discharges completely.
The pollution propensity of the wastes produced
in the leather industry can be reduced
by methods such as converting waste hair into
a fertiliser, recycling chrome liquor and reducing
salt discharges through hide drying technologies.
In order to facilitate the adoption of Cleaner
Production technologies with piggery wastes
in the Pacific Island countries, participatory
methods and action research are being used
to encourage community involvement.
Nutrient audits of farms using farmyard manure
applications to improve crop yields
showed that Indian farmers under-fertilised
their crops, whereas Australian farmers overfertilised
them.