Domestic waste (tonnes / annum)
|
Food waste (%)
|
Food waste (tonnes / annum)
|
Low
|
5 600 116
|
18.08
|
1 012 688
|
Middle
|
2 929 639
|
10.98
|
321 577
|
High
|
1 093 352
|
9.58
|
104 713
|
Total
|
9 623 106
|
|
1 438 977
|
All garden and food waste is recyclable provided that the most suitable treatment options are considered. The different recycling/treatment options available for organic waste is summarized in Table 9.
Table : Organic waste treatment options available (DEADP, 2011)
Method
|
Potential Input Waste Type
|
Output product
|
Windrow composting
|
Garden waste, wood waste, manures, fruit waste
|
Compost, soil conditioner
|
Vermi-composting
|
Food and garden waste
|
Compost, soil conditioner
|
Enclosed composting
|
Mixed organics (food and garden waste) and sewage sludge
|
Compost, soil conditioner, high calorific value
|
Anaerobic digestion
|
Mixed organics (food and garden waste) and sewage sludge
|
Biogas, green energy, soil conditioner
|
Fermentation
|
Agricultural waste, mixed organics
|
Liquid fuel
|
GW 30 – Construction and demolition waste
The Waste Act, 2008 (RSA, 2008) defines building and demolition waste as “waste excluding hazardous waste, produced during the construction, alteration, repair or demolition of any structure and includes rubble, earth, rock and wood displaced during that construction, alteration, repair or demolition”. Structures referred to can include residential and non-residential buildings, and public works such as roads, bridges, piers and dams (Macozoma, 2002). As such, construction and demolition waste includes, but is not limited to, concrete, bricks, masonry, ceramics, metals, plastic, paper, cardboard, gypsum drywall, timber, insulation, asphalt, glass, carpeting, roofing, site clearance, excavation material and site sweepings (Macozoma 2002). It is therefore clear that building and demolition waste as defined by the Act is likely to be contaminated with other wastes.
Some IWMPs report builder’s rubble data, but this is the exception rather than the rule. It is difficult to calculate waste generation data because it is such a complex waste stream.
Viljoen, (2010) estimated that construction and demolition waste in the Western Cape comprise of:
-
concrete and masonry (33.3 %),
-
wood (25.0 %), and
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drywall (12.5%).
Viljoen (2010) also identified the most critical sources of waste during construction as follows:
-
Waste of materials (75%)
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Rework (58.3%)
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Over-allocation of materials (45.8%)
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Deterioration of materials (41.7%).
Recycling data is calculated at 630 000 tonne/annum in 2007 (Dti, 2009). It should also be noted that builders’ rubble are often used as cover material at landfills while informal recycling and reuse is likely to be unreported.
This baseline estimated a recycling rate of about 16% for construction and demolition waste.
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