Miljø- og samfundsøkonomisk vurdering af ... - Miljøstyrelsen

The greenhouse effect represents the largest saving (measured in mPE) among all environmental
impact categories. The baseline scenario results in a saving of 116 mPE / ton of household waste,
which is the smallest saving of all(see Figure B). Scenarios 3A, 3F, 4, 5F, 6A, 6F and 7, all having a
maximum separation of waste fractions for recycling, are the best scenarios resulting in savings of
approx. 138 mPE / ton of household waste. This is approx. 19 % better than the baseline scenario
and corresponds to a reduction of the total Danish greenhouse gas emissions by approx. 0.5 %
(2011-numbers).
Ikke-toksiske kategorier
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Drivhuseffekt Forsuring Næringssaltbelastning Fotokemisk smog Ozonnedbrydning
0
-20
mPE / ton dagrenovation
-40
-60
-80
-100
-120
-140
-160
1 2A 2F 2Z 3A 3F 3Z 4 5A 5F 6A 6F 7
Figure B
Total non-toxic potential environmental impacts of the 13 scenarios for a mixed catchment area.
The scenarios involving biological treatment have larger environmental impact in the category
nutrient enrichment than scenarios without biological treatment due to nitrate leaching from the
use of digestate / compost on agricultural land 17. Environmental savings in the impact category
acidification are in the same range for all scenarios. The impacts on photochemical smog and ozone
depletion are small in all scenarios. The toxic environmental impacts are also small (see Figure C),
and furthermore, the calculations of the toxic impacts are subject to a large uncertainty.
By ranking the scenarios with respect to all environmental impact categories, no single scenario can
be considered the best in all categories and thereby without prejudice be assigned the best
environmental profile. 18 However, for the non-toxic impact categories, scenarios 3, 4, 5, 6 and 7 are
generally ranked higher - i.e. better - than scenarios 1 and 2 (with the exception of nutrient
enrichment, where scenario 1 is ranked high); therefore increased recycling rates seem to cause
higher environmental savings. Scenarios 2z and 3z results in slightly smaller potential
environmental savings in all environmental impact categories, as the optical bag sorting plant is
directing a small part of the correctly source-separated waste to incineration. Moreover, this
concept consumes an extra amount of plastic bags and energy. For the toxic categories, the ranking
of the scenarios is more unclear, and - considering the uncertainties in the calculations - no
conclusions can be made on these environmental impact categories.
17
This will generally apply when using organic fertilizers compared to the use of artificial fertilizers. The
comparison between use of compost, digestate and pig manure is shown in the Annex report, Annex 10,
however, these considerations are not in accordance with the requirements for an impact LCA and are thus not
included in the main report.
18
No weighting is used (not allowed under ISO 14040 standards in a comparative LCA report, available to the
public).
Miljø- og samfundsøkonomisk vurdering af muligheder for øget genanvendelse af papir, pap, plast, metal og organisk affald fra
dagrenovation
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