Page 125 - Materials Chemistry, Second Edition

3.3 Allocation 109

For these secondary raw materials well-developed collecting systems and appli-
cations exist (but are not applied in all countries). A market for such materials has
formed and is actually quite old (e.g. scrap). Some examples: Today in Germany
newsprint, almost exclusively, and cardboard, to a large extent, are produced from
waste paper or waste carton. Waste glass is added in a certain proportion for bottle
production, and a high portion of scrap iron has for a long time been employed
with some steel grades. It is nevertheless rarely known into which new product (B)
or products (B, C, D, … ) the secondary raw material from the examined system
is integrated. System expansion in these cases is thus not feasible or only with
very uncertain assumptions. Usually only the product group is known, whereby the
secondary raw material is preferably applied.
Allocation rules 104) present an alternative to system expansion.

3.3.4.2 Allocation per Equal Parts
The seemingly simplest and oldest rule is the so-called 1 : 1 – or 50 : 50 – Rule 105)
1. Waste avoidance in A gets a credit entry to even parts in systems A and B.
2. Raw material saving in B likewise gets a credit entry to even parts in systems
Aand B.

However, this arbitrary rule – but nevertheless regarded as just – also presup-
poses knowledge of both systems. The advantage to system expansion consists of the
fact that allocation can be limited to specific process steps (see Figures 3.19–3.21).
For a system expansion, however, the complete system B must be assessed.

Polymer Polymer
production production
(PP-A) (PP-B)

Production A: Secondary raw Production B:
production and material production and
use (leaves system A) use
(Pr-A) (Pr-B)

MSWI MSWI
(MSWI) (MSWI B)

System A: System B:
PP-A + Pr-A + MSWI-A PP-B + Pr-B + MSWI-B

Figure 3.19 Process pattern of noncoupled systems 106) (disposal here: municipal solid
waste incineration – MSWI).

104) Huppes and Schneider, 1994; Kl¨ opffer, 1996a; Ekvall and Tillman, 1997; Curran, 2007, 2008.
105) SETAC, 1991; EPA, 1993; Kl¨ opffer, 1996a; UBA, 2002; EPA, 2006.
106) IFEU, 2006.