Human Settlements Theme Report

Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Professor Peter W. Newton, CSIRO Building, Construction and Engineering, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06747 7

Waste, recycling and reuse (continued)

Solid, liquid and hazardous wastes

  • Generation of wastes
  • Waste classification and composition
  • Transportation, storage and disposal of hazardous waste
  • Waste minimisation
  • Resource depletion and recycling
  • Contamination of land
  • Implications
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    Generation of wastes

    Substantial quantities of waste are generated from human consumption and activities related to the construction, operation, maintenance and renewal of human settlements. For 1996-97, ABS (1998l) estimated that 21.2 million tonnes of solid wastes were received and disposed at landfills nationwide. This equates to a per capita solid waste disposal of 1.1 tonnes/year (Figure 80), placing Australia among the top 10 solid waste generators within the OECD (OECD 1999). Among Australian states and territories, the per capita rate of waste generation ranges from approximately 800 kg/year in the ACT to almost 1400 kg/year in Western Australia.

    Figure 80: Solid waste disposal in Australia. [HS Indicators 10.1 and 10.2]

     Solid waste disposal in Australia.

    Source: ABS (1998l).

    The primary pressure from waste generation is the need for disposal, and the consequent environmental impacts. The main form of waste disposal in Australia is landfill, which accounts for over 95% of solid waste disposal in some states and territories (see photograph). The impact of landfill disposal includes consumption of increasingly scarce urban land, potential leachates from toxic wastes, release of methane from the decomposition of organic wastes, and greenhouse emissions through the transportation of wastes to landfills, which are located mostly on the fringes of cities.

    Existing landfill capacity in some urban settlements is extremely scarce and proposals for new landfill sites often meet with community opposition (EPA NSW 1997). In New South Wales, the EPA estimated that existing landfill capacity would not last beyond 2007 at present rates of waste disposal. If the state waste reduction targets of 60% by the year 2000 were met, the existing landfills would last another eight years.

    Landfill disposal

    Landfill disposal.

    Source: CSIRO.

    The immediate pressure from landfill disposal is partially reflected in pricing trends. The large discrepancy between landfill fees in Sydney ($60-$100/tonne) and the other major metropolitan centres ($25-35/tonne) provides an indication of the cost of urban land consumption. In addition to these 'gate' fees, most state EPAs have imposed a waste levy, generally ranging between $3-5/tonne and up to $17 a tonne in Sydney. These levies are used to support waste management initiatives within each state (e.g. EcoRecycle in Victoria).

    The waste generation characteristics of human settlements throughout Australia can be inferred from data on waste disposal and waste diversion. The former is principally waste disposed in landfills, and the latter includes waste quantities reused or recycled. Therefore, the total amount of waste which potentially affects environmental quality would be roughly the sum of wastes disposed, diverted, reused and recycled.

    In general, data on waste generation in Australia is patchy, and waste data has been collected only relatively recently in some states and territories. The primary data sources on waste are state Environmental Protection Agencies or Authorities (EPAs) and, where they exist, waste boards or other government agencies overseeing waste minimisation programs. Waste data is obtained primarily through the collection of landfill levies and various waste collection services. An Australian Waste Database has also been established, drawing data primarily from state EPAs (S. Moore, University of New South Wales, pers. comm., 2000).

    A National Pollutant Inventory (NPI) has also been established, consisting of a database on emissions to the environment, including those of a hazardous nature or involving significant impact on human health and the environment (Environment Australia 2000).

    Waste classification and composition

  • Municipal and domestic wastes
  • Construction and demolition wastes
  • Commercial and industrial waste
  • Sewage sludge and bio-solids
  • Hazardous or prescribed wastes
  • Low-level radioactive wastes
  • Generation of industrial and mineral wastes
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    Wastes from human settlements are generally categorised as either urban solid wastes or hazardous/prescribed wastes. Urban solid wastes are further classified under three subcategories, namely:

    • municipal (M) - domestic and council,
    • commercial and industrial (C and I), and
    • construction and demolition (C and D).

    The composition of urban solid wastes can vary significantly and is indicative of the modes of economic activity and drivers for waste generation in each urban centre. Across the major capital cities, overall waste composition is as follows: 40% domestic waste, 23% C and I waste and 37% C and D waste (Table 68). In inner Sydney, only 14% of total urban waste was municipal in origin, while 60% was due to construction and demolition (Inner Sydney Waste Board 2000). The relatively high level of C and D wastes has been attributed to high levels of ongoing development, activities related to the Olympics, and the government's urban consolidation policy (Sullivan 2000).

    Table 68: Composition of solid waste in major metropolitan centres. (Percentages by weight.)
      Inner SydneyA Sydney metroB ACTC BrisbaneD MelbourneE Perth metroF TasmaniaG AverageH
    Municipal 14 36 40 51 34 28 50 40
    Commercial & industrial 26 40 24 17 32 17 26 26
    Construction & demolition 60 23 36 32 34 55 24 34

    A1996-97 (Inner Sydney Waste Board 2000).
    BAverage 1995-1999, data supplied by EPA NSW, 2000.
    CAverage 1994-1999, domestic including private delivery (ACT Government 2000).
    D1994 (EPA Queensland 1999).
    E
    1996-97 (EcoRecycle Victoria 1998a, 1998b).
    F
    Average 1997-2000 (Department of Environment Protection WA, 2001).
    GData supplied by Department of Primary Industries, Water and the Environment, Tasmania, 2000.
    HExcluding inner Sydney.

    Municipal and domestic wastes

    The rate of domestic waste generated cannot be determined accurately because there is a discrepancy between waste generation and waste disposal. Waste data generally relates to quantities disposed or collected for off-site recycling. Therefore, domestic wastes that can find on-site reuse such as composting of garden wastes, are not quantified. Neither do these wastes constitute a direct pressure on landfill.

    Approximately 40% of all solid wastes are municipal or council wastes, much of it from domestic households. The per capita disposal rate for municipal waste in Australia is 620 kg/year, placing it second only to the USA, as shown in Figure 81 (OECD 1999). Domestic or household waste streams typically include garden wastes, paper, glass, plastic and food wastes. The rate of household waste disposal in Australia is among the highest 10 in the OECD (OECD 1999). Based on 1996-97 data, the per capita disposal of domestic waste in Australia was approximately 400 kg/year (OECD 1999).

    Within the municipal waste stream, a number of specific solid waste streams pose significant environmental impacts and costs. The NSW EPA has estimated that almost six million used car tyres require disposal each year in New South Wales. Of these, 45% are transferred to landfill, while 25% are improperly disposed through dumping, burning or stockpiling (EPA NSW 1997). Apart from landfill pressures, tyre stockpile fires emit toxic gases that pollute the environment.

    Litter is also a significant problem and cost to many municipalities. In Queensland, 50% of councils spend more than $25 000 each annually on litter collections (EPA Queensland 1999). The Gold Coast City Council alone collects approximately 1500 tonnes of litter each year, including cigarette butts, bottles, cans, paper and packaging materials (EPA Queensland 1999). Since streets and gutters cover one-third of the urban 'catchment' area, loose litter can contribute significantly to stormwater pollution, which in turn causes poor water quality on beaches and waterways (EPA NSW 1995).

    Figure 81: Top 10 municipal waste disposers in the OECD. [HS Indicators 10.1 and 10.2]

     Top 10 municipal waste disposers in the OECD.

    Source: OECD (1999); data generally for 1995-1997.

    Construction and demolition wastes

    Construction and demolition (C and D) of buildings contributes 30-40% of all solid wastes disposed at landfill. This equates to approximately eight million tonnes nationwide, or 430 kg/year per capita. C and D waste streams typically consist of concrete, soil/rubble, clay or timber-based materials and plasterboard. In Victoria, 1.4 million tonnes of C and D wastes were sent to landfill, of which almost 25% was concrete (EcoRecycle Victoria 1998b).

    Between 60% and 70% of C and D wastes are generated during the demolition of residential and commercial buildings, while the remainder are generated during construction and other forms of civil engineering and roadworks. The breakdown of contributing sources for C and D wastes are shown in Table 69. The relative contribution from the residential and commercial sectors varies regionally. The contribution from the commercial sector in inner Sydney was between three to four times higher than the contribution from the residential sector. In the remaining Sydney metropolitan region, as well as in Melbourne, the contribution from the commercial sector was lower than that of the residential sector.

    Table 69: Percentage contributions to the C and D waste stream from residential and commercial construction and demolition.A
    Category Melbourne Inner Sydney Remaining Sydney metroB
    Residential demolition 39.3
    15.6
    34.6
    Commercial demolition 33.3
    48.2
    30
    Residential construction 10.5
    4.8
    19.5
    Commercial construction 4.9
    20.3
    12
    Other-civil works and road construction/demolition 12.0
    11.1
    3.9

    AMelbourne data by volume; Sydney data by tonnage.
    BNorthern, western and southern.

    Sources: EcoRecycle Victoria (1998a); Inner Sydney Waste Board (2000).

    The temporal and regional trends may indicate specific causes related to the economic climate or the impacts of legislation. However, the relatively inexact nature of waste accounting and the significant data gaps can make regional comparison difficult, as noted by Moore (2000).

    Commercial and industrial waste

    Commercial and industrial (C and I) wastes typically contribute 10-20% of the total urban solid waste stream. The primary sources of C and I wastes are commercial establishments and non-biodegradable wastes from industrial and manufacturing processes. Significant quantities of industrial wastes are also generated from power generation, minerals processing and mining industries but are not counted under urban solid wastes. The C and I sector generates urban solid wastes and hazardous wastes. Solid waste from the C and I sector has a very wide range of composition that arises from the packaging, food and hospitality industries, and manufacturing. A small fraction of commercial and industrial wastes are currently reused or recycled, the majority being either stockpiled or disposed of to landfill.

    Sewage sludge and bio-solids

    Bio-solids are the dry by-product of sewage treatment and are rich in plant nutrients. There are indications that the rate of bio-solids reuse is increasing. Between 1992 and 1998, Sydney Water Corporation collected an average of 41 000 dry tonnes of bio-solids every year. While the generation rates did not changed significantly over this time (Figure 82), the rate of beneficial reuse has improved dramatically, from 67% in 1992-93 to 99.5% in 1997-98. The bulk of this reuse is in agriculture and composting/horticulture (67.5% and 25% respectively in 1997-98; Sydney Water Corporation 1998). A longer-term strategy for improving the handling and transporting of bio-solids for Sydney is currently being developed (Sydney Water Corporation 2000). In Brisbane, 20 000 tonnes of bio-solids need to be disposed of annually. With on-site stockpiling being phased out, options that are being considered include incineration, worm reactors and pelletisation (Brisbane City Council 1998).

    Figure 82: Dry bio-solids collected by Sydney Water Corporation and portion beneficially used, 1992-1998. [HS Indicator 10.6]

     Dry bio-solids collected by Sydney Water Corporation and portion beneficially used, 1992-1998.

    Source: Sydney Water Corporation (1998).

    Hazardous or prescribed wastes

    Hazardous or prescribed wastes may originate from all sectors, but the majority are generated by the commercial, industrial and trade sectors. Sources of prescribed industrial wastes include hospitals; food outlets; chemical, paint and plastic manufacturers; and food processing plants. Potentially hazardous wastes of domestic origin include paints, solvents, used car batteries and motor oils. Hazardous or prescribed wastes require careful management and/or treatment due to their potential to harm the environment and the community. The environmental or health risks from these wastes may arise because of their toxicity, flammability, leachability or odour (EPA Victoria 1999). Data from New South Wales and Victoria suggests that more than 50% of prescribed wastes are generated from the manufacturing sector (EPA NSW 1997, CRC for Waste Management and Pollution Control 1998, EPA Victoria 1999). The actual composition of hazardous wastes is extremely varied, but in general, solid hazardous wastes constitute up to 60% of the total hazardous waste stream, as shown in Figure 83. In both Victoria and New South Wales, the quantity of hazardous waste generation has been increasing in recent years. Between 1992 and 1996, the amount of hazardous wastes generated in Sydney more than doubled, from 170 000 to 422 000 tonnes (EPA NSW 1997).

    Figure 83: Generation of solid and hazardous wastes in Victoria. [HS Indicator 10.7]

     Generation of solid and hazardous wastes in Victoria.

    Source: EPA Victoria (1999).

    Low-level radioactive wastes

    Australia currently generates 60 cubic metres of low-level radioactive wastes (LLRW) annually, mainly from industrial and research uses involving radioactive materials. (This figure does not include uranium mining wastes, which are disposed of locally at mine sites.) This is a relatively low generation rate when compared to countries such as France and Britain, each of which generates 25 000 cubic metres per annum (DISR 2000a, 2000b). The estimated annual global output of low and intermediate radioactive wastes from nuclear power generation is 150 000 cubic metres (Uranium Information Centre 2000). Over the last 40 years, Australia has accumulated some 3500 cubic metres of low-level short-lived intermediate nuclear wastes. Currently, a national repository for LLRW is being planned for siting in the central north region of South Australia (DISR 2000c).

    Generation of industrial and mineral wastes

    The geographic distributions of minerals and petroleum industries across Australia are highly localised. For instance, Western Australia, with only 10% of the Australian population, accounts for 40% of the production of Australia's minerals and petroleum commodities, and mining remains the major export earner for Queensland. Regulatory frameworks relating to the protection of the adverse effects of mining and industrial operations have continued to increase in number and complexity.