Share of recycled input percent

Figure 12.1 Current mix of recycled and virgin inputs of selected products (EPA, 2006c)

As figure 12.1 indicates, for corrugated cardboard, approximately two-thirds consist of recycled material. The portion of recycled paper in new paper products is in the wide range of between 10 and 50 percent. It strongly depends on the quality needs of the target product. Thus, the choice of the paper quality for a certain application also strongly influences GHG effects. In the case of aluminum or steel cans, nearly half of the raw material used is recycled. The portion of recycled plastics is relatively low.

Greenhouse gas effects by source reduction are given in figure 12.2 for selected materials for the two cases discussed: In "source reduction (virgin)" material was prepared only of virgin material. In "source reduction (mix)" the current mix of virgin and of recycled material is considered. As a third column the case of recycling instead of source reduction is presented - for details see later.

Figure 12.2 GHG effects of source reduction and recycling (EPA, 2006c)

Obviously, credits by source reduction using virgin material are always higher than for mixed inputs. The difference depends on production emissions. In the case of aluminum for which the emission reduction is highest amongst the materials displayed in figure 12.2 GHG effect of source reduction of 100 percent virgin material is about twice the value of mixed material due to high energy input into aluminum production (see also chapter 10.2.4.). In practical cases source reduction of aluminum will result in about 8 t CO2-eq. per ton of material. Other important source reduction effects result with copper and specific paper grades. Source reduction activities therefore should first focus on these materials.

12.2.2.2 Waste material recycling effects

Material that is recycled after first use is then substituted for 100 percent virgin inputs in the production of new products. Emissions are lower in the case of using recycled inputs rather than virgin inputs, which results in credits.

For the calculation of the credits loss rates during the whole process of collection of waste material, its processing, and for remanufacturing have to be considered: 100 percent recycling is not possible. Less than one mass unit of new material is made from one mass unit of the recovered material. Table 12.3

displays typical loss rates for recovered material. Depending on material data are based on closed- and open-loop recycling.

Table 12.3 Loss rates for recovered material (EPA, 2006)

Material

Recovered material retained in the recovery stage

(percent)

Product made

(t/t of recycled inputs)

Loss rate

t product per t recovered material

kg lost per ton of recovered

Steel cans

100

0.98

0.98

20

Aluminum cans

100

0.93

0.93

70

Corrugated cardboard

100

0.93

0.93

70

Newspaper

95

0.94

0.90

100

Glass

90

0.98

0.88

120

Dimensional lumber

88

0.91

0.80

200

Medium-density fibreboard

88

0.91

0.80

200

HDPE

90

0.86

0.78

220

LDPE

90

0.86

0.78

220

PET

90

0.86

0.78

220

Phonebooks

95

0.71

0.68

320

Magazines/Third class mail

95

0.71

0.67

330

Textbooks

95

0.69

0.66

340

Office paper

91

0.66

0.60

400

Calculations of climate effects of recycling based on these assumptions are shown in figure 12.2 in terms of the reduction of greenhouse gas emissions. The numbers characterize the improvement of emissions due to a waste generation reference point which is defined as the situation when the material has already undergone the acquisition of the raw material and the manufacturing phase. For more GHG reduction dates from selected material see table 12.14. Figure 12.2 indicates that for all the materials considered a reduction of greenhouse gas emissions would occur if a source reduction or a recycling takes place. Again, as was true in the case of source reduction, the greatest potential for emission reduction applies in the case of aluminum cans and several paper grades. Thus, if such measures are intended, they should start with these materials, depending on the concrete waste management situation.

Emission reductions caused by recycling activities are due to several factors, which contribute to total GHG reductions, namely the process energy, transportation energy as well as process emissions which are not energy related. Figure 12.3 represents recycled input credits for selected materials.

16,00

14,00

16,00

14,00

Aluminium Copper Steel cans LDPE PET HDPE Glass cans wire

■ Process energy □ Transportation energy 0 Non energy process

Figure 12.3 Effect of recycling process steps on emission reduction (EPA, 2006c)

In most cases the credits for the reduction of the process energy related emissions dominate. In the case of aluminum this amounts about 11 t CO2-eq. per ton of recycled material used instead of virgin material. For aluminum also emissions from the process itself are a relevant factor. In the case of paper and products made from it positive recycling effects are also due to forest carbon sequestration which amounts up to 2 t CO2-eq. per ton of wood (EPA, 2006).

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