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Municipal Solid Waste (MSW)

Municipal Solid Waste (MSW) accounted for less than 13% of all waste produced in the South West, but contributed 35% to the materials and waste ecological footprint (13% of the total South West residents' ecological footprint).

Base case

To provide a benchmark against which to gauge the ecological performance of the scenarios, the following base case assumptions were made:

  • The composition of MSW is constant in all MSW scenarios. Table 16 shows the assumed materials and product composition of MSW.
  • Waste arisings of 522 kg per person in 2001 (EA & RATB, 2004).
  • In 2001, 85% of waste was landfilled, 15% was recycled or composted and 0.1% was used to produce energy (EA & RATB, 2004). For further discussion on calculating energy recovered from waste see Appendix 1.
Table 16
Base case municipal solid waste generated in the South West, by product type, in 2001
 
Material/product type % by weight
Putrescibles 31%
Paper & card 21%
Other combustibles 11%
Other non-combustibles 8%
Plastic 7%
Glass 6%
Metals 6%
Fine material 5%
Textile 2%
Electrical equipment 2%
Other MSW 1%
 
Source: SWRA, 2003a

The ecological footprint of MSW per person in the South West in 2001 was 0.76 gha.

Scenario 1: Business as usual

This scenario is based on Option 0 (SWRA, 2003b) and illustrates the ecological footprint with no change in current MSW management in the South West between 2001 and 2020.

Assumptions:

  • 2020 waste arisings of 709 kg per person.
  • Waste growth of:
    • 2001 – 2006, 3.5% per year,
    • 2007-2015 growth declines towards zero,
    • 2016-2020 zero growth (SWRA, 2003a).
  • In 2020, 85% of waste is landfilled, 15% is recycled or composted and 0.1% is used to produce energy (SWRA, 2003b).

This scenario gives an ecological footprint for MSW in 2020 of 1.03 gha per person, an increase of 0.27 gha (35%) on the base case.

Scenario 2: Increased recycling and composting, no landfill

This scenario is based on Option 5 (SWRA, 2003b), which gained the best score of all the different waste management options according to the sustainability appraisal. The sustainability appraisal used criteria normally included in a 'Best Practicable Environmental Option' (BPEO) assessment, such as energy use, number of jobs created and noise.

Assumptions:

  • 2020 waste arisings of 709 kg per person.
  • Waste growth of:
    • 2001 – 2006, 3.5% per year,
    • 2007-2015 growth declines towards zero,
    • 2016-2020 zero growth (SWRA, 2003a).
  • By 2020, no waste is landfilled, 45% is recycled or composted and 55% is used to produce energy (SWRA, 2003b).

This scenario gives an ecological footprint for MSW in 2020 of 0.85 gha per person, an increase of 0.09 gha (12%) on the base case.

Scenario 3: Increased recycling and composting, with mechanical biological treatment (MBT) and waste to energy

This scenario is based on Option 4c (SWRA, 2003b) and principally manages waste through recycling and composting. The residual waste is further recovered using mechanical biological treatment. The final residual waste is primarily used to produce energy.

Assumptions:

  • 2020 waste arisings of 709 kg per person.
  • Waste growth of:
    • 2001 – 2006, 3.5% per year,
    • 2007-2015 growth declines towards zero,
    • 2016-2020 zero growth (SWRA, 2003a).
  • By 2020, 6% of waste is landfilled, 67% is recycled or composted and 28% is used to produce energy (SWRA, 2003b).

This scenario gives an ecological footprint for MSW in 2020 of 0.78 gha per person, an increase of 0.02 gha (<3%) on the base case.

Scenario 4: Increased recycling and composting, with mechanical biological treatment

This scenario is based on Option 2 (SWRA, 2003b), which gained the best score of all the different waste management options according to the ecological footprint. This scenario achieves exceptionally high levels of recovery (recycling, composting and MBT) and uses landfill to dispose of the residual waste.

Assumptions:

  • 2020 MSW arisings of 709 kg per person.
  • Waste growth of:
    • 2001 – 2006, 3.5% per year,
    • 2007-2015 growth declines towards zero,
    • 2016-2020 zero growth (SWRA, 2003a).
  • By 2020, 25% of waste is landfilled, 75% is recycled or composted and no waste is used to produce energy (SWRA, 2003b).

This scenario gives an ecological footprint for MSW in 2020 of 0.77 gha per person, an increase of 0.01 gha (<2%) on the base case.

Scenario 5: One planet lifestyle

This scenario is an attempt to meet environmental sustainability criteria. The criterion used for this scenario is the 'earthshare', taken from the National Footprint Accounts (Redefining Progress 2002), which assumes the human race lives within the natural limits of our planet. With the current ecological footprint of a South West resident at 5.56 gha/person, an overall reduction of 66% is required to meet the earthshare criterion.

This scenario illustrates what further measures would be required to achieve environmentally sustainable MSW management in the South West. This scenario uses the same waste management regime as Scenario 4, but also reduces the amount of waste produced.

Assumptions:

  • 2020 MSW arisings of 227 kg per person, representing waste reduction of 4% each year for 20 years (to 2020).
  • By 2020, 25% of waste is landfilled, 75% is recycled or composted and no waste is used to produce energy (SWRA 2003b).

This scenario gives an ecological footprint for MSW in 2020 of 0.25 gha per person, a reduction of 0.51 gha (77%) on the base case. This is a reduction by weight of 56%, 295 kg per person less than the base case.

Reduction of the ecological footprint

The municipal solid waste (MSW) scenarios display possible variations in the estimated MSW ecological footprint for 2020, achievable through changes in MSW arisings and management technologies. Figure 7 shows the ecological footprints for the 2001 base case and each of the MSW waste scenarios.

Scenario 1 (business as usual) shows the largest ecological footprint increase, with Scenario 4 showing the smallest increase in ecological footprint achievable when using only waste management changes. Scenario 5 (one planet lifestyle) shows what could be achieved using waste management (as in scenario 4) and waste minimisation together.

Figure 7
Municipal solid waste base case and scenario ecological footprints for the South West, in 2020

fig 7

Measuring the sustainability of the South West's waste management

The Developing a Regional Waste Strategy for the South West Regional Assembly (SWRA, 2003b) technical report uses a mixture of quantitative and qualitative indicators to assess the overall sustainability of its proposed options. The indicators included:

  • Environmental Indicators: such as energy, greenhouse gases and noise,
  • Socio-economic Indicators: such as number of jobs likely to be created,
  • Operational Indicators: such as costs and reliability of delivery, and
  • Waste Management Indicators: such as % recovered and % recycled/composted.

Each indicator was weighted by asking representative stakeholders the relative importance they placed on each indicator. Then for each proposed option, values were given to each indicator on a scale of 0-1, where 0 was the worst and 1 the best. Combining these values with the weightings gave a score for each indicator. The scoring process aligned the results and allowed for comparisons.

In contrast, the ecological footprint measures resource use (materials and energy) and is an indicator of environmental sustainability. The ecological footprint does not consider any social or economic aspect of sustainability. Comparing resource use with the resources available gives a measure of environmental sustainability.

Figure 8 shows the weighted score for scenarios 1-4 (highest is best) alongside the ecological footprint (lowest is best). The base case and one planet scenario do not have a weighted score because they were not included in the Developing a Regional Waste Strategy for the South West Regional Assembly (SWRA 2003b) technical report.

Weighted scores and ecological footprints were applied to all of the Developing a Regional Waste Strategy for the South West Regional Assembly (SWRA 2003b) technical report options. The results can be found in Additional Information.

Figure 8
Ecological footprints and weighted scores for municipal solid waste scenarios

fig 8