to read the full report - Ecolateral by Peter Jones
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50<br />
Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Wastes and Energy<br />
AEA/ED45551/Issue 1<br />
4.4.6 Conclusions<br />
Bio-solids are <strong>the</strong> product of <strong>the</strong> waste-water treatment works. Even after several stages of treatment it is<br />
still largely comprised of water.<br />
Increasing waste-water legislation, and increasing population in <strong>the</strong> UK, results in increased volumes of<br />
bio-solids: up <strong>to</strong> 1,368,000 dry <strong>to</strong>nnes in 2004. Much of this waste is ultimately recycled <strong>to</strong> land as a<br />
fertiliser but this use will be restricted in <strong>the</strong> future due <strong>to</strong> tighter regulation of nitrogen application <strong>to</strong><br />
agricultural land in some sensitive areas.<br />
4.5 Agricultural Residues and Waste<br />
4.5.1 Definition<br />
Agriculture produces a variety of residues, but only limited waste. The distinction is made between<br />
controlled wastes and uncontrolled resides. Wastes are items such as chemicals, plastic, containers and<br />
o<strong>the</strong>r packaging, and controls on this waste stream were introduced in May 2006. Agricultural waste is<br />
<strong>to</strong>o heterogeneous and widely dispersed <strong>to</strong> provide an easy feeds<strong>to</strong>ck. Agricultural residues include<br />
animal manures and slurry, and crop straws and husks, which rarely leave <strong>the</strong> confines of a farm, and<br />
<strong>the</strong>refore are not recorded. Such residues are generally homogeneous which makes <strong>the</strong>m a more<br />
realistic potential feeds<strong>to</strong>ck. Manure and slurry sp<strong>read</strong> at <strong>the</strong> place of production, for <strong>the</strong> benefit of<br />
agriculture, is not considered <strong>to</strong> be waste under <strong>the</strong> current regulations. In 2005 <strong>the</strong> European<br />
Commission judged that lives<strong>to</strong>ck effluent would fall outside <strong>the</strong> classification of waste if it were<br />
subsequently used as a soil fertiliser. 73 The application of <strong>the</strong>se residues <strong>to</strong> land is a traditional practice<br />
that helps <strong>to</strong> replenish nutrients, and reduces <strong>the</strong> amount of artificial fertiliser that would o<strong>the</strong>rwise be<br />
applied.<br />
However, agricultural residues can lead <strong>to</strong> air, land and water pollution if not managed properly. Farm<br />
slurries are many times more polluting than human sewage and when not correctly managed can cause<br />
serious environmental damage, particularly <strong>by</strong> adulterating watercourses and producing odours. Heavy<br />
fines can be imposed on farmers for pollution of watercourses with animal slurries. In addition traditional<br />
disposal methods are increasingly leading <strong>to</strong> problems. Defra now advise against general sp<strong>read</strong>ing of<br />
slurry for example, due <strong>to</strong> concerns about <strong>the</strong> loss of ammonia <strong>to</strong> <strong>the</strong> air. Such concerns are a major<br />
driver <strong>to</strong> re-evaluate <strong>the</strong> methods for treating and disposing of farm wastes and residues.<br />
4.5.2 Composition<br />
Agricultural residues can be subdivided in<strong>to</strong> two categories:<br />
• Wet residues are animal slurries and farmyard manures that have a solid content of under 15%.<br />
• Dry residues include straw, husks and processing waste, as well as poultry litter from poultry<br />
reared for meat.<br />
73 European Court judgment, Case C-416/02 European Commission v Kingdom of Spain,<br />
http://europa.eu.int/smartapi/cgi/sga_doc?smartapi!celexplus!prod!CELEXnumdoc&lg=en&numdoc=62002J0416.