SUbstance flow analysis of the recycling of small waste electrical ...

40 Substance flow analysis of the recycling of small WEEE
Scheidt et al. (2008) distinguished the following methods of reuse: (1) sell the product to
another user, (2) donate the product to another user, (3) if the product is damaged, restore
the product prior to moving it to another user and (4) harvest components from it. Regarding
re-use of WEEE in practice, three kinds of re-use activities can be differentiated:
Re-use of working equipment,
Re-use of equipment after repair and/or refurbishment, and
Re-use of parts or components.
Re-use processes fall under the scope of some guidelines on WEEE management (Appendix
4 summarizes the scope and other information on these guidelines). Li et al. (2008) wrote
that before entering the waste stream, there is “huge” potential for re-use of EEE, but only
1.27% of products in the WEEE collection system in Germany are economically reusable.
According to Rose & Stevels (2001), discarded consumer EEE in Europe is regarded as
economically or technically so old that higher levels of reuse options are usually not
attractive. In the USA, managers of end-of-life facilities indicated that only about 10 to 15% of
residential WEEE, which is typically much older and more heterogeneous than commercial
WEEE, has resale value. About 90% of the commercially generated IT waste equipment had
resale value, but less than 50% is refurbished and resold due to customer requirements that
equipment should be destroyed (Rifer et al. 2009).
2.4.4. Treatment
The chain of pre-processing, recovery and disposal processes used to recover the materials
and substances contained in sWEEE (Figure 3) is called in this thesis the ‘treatment process
chain’. According to the WEEE Directive, ‘treatment’ means any activity after the WEEE has
been handed over to a facility for depollution, disassembly, shredding, recovery or
preparation for disposal and any other operation carried out for the recovery and/or the
disposal of the WEEE.
Recommendations for treating WEEE in the form of standards, manuals and guidelines have
been issued by different groups (Appendix 4). The actual amount of precious metals
recovered, and hence the amount of precious metals leaving the cycle, depends on the
overall efficiency of the chain of material recovery processes during the end-of-life phase. In
turn, this efficiency is affected by both the design of the product and the combination of preprocessing
and recovery processes in the end-of-life phase (Castro et al. 2005).
2.4.4.1. Pre-processing
As first step of the treatment process chain, pre-processing determines to which recovery or
disposal processes the materials are fed (Paper 2). Pre-processing is divided into three
major stages: (1) sorting, (2) selective disassembly, targeting on singling out (liberating)