Recycling – From Waste to Resource
An Assessment of the Optimal Manual Dismantling Depth of a Desktop PC in China based on Eco-Efficiency Calculations

Diploma Thesis of Simon Gmünder, sc. nat. env. ETH , simon.gmuender@gmail.com
Supervision: Dr. M. Streicher-Porte, Swiss Federal Laboratories for Materials Testing and Research (EMPA)
Thesis Tutor: Prof. Dr. S. Hellweg, Institute of Environmental Engineering, ETH Zurich

Abstract
The main strength of the Chinese e-waste recycling system is the efficient manual pre-processing, which is the basis for a high material recovery rate. However, primitive and hazardous processes are applied frequently when it comes to the actual recovery of complex material, such as printed wiring boards (PWBs). The existence of such primitive recycling techniques combined with the upcoming e-waste amounts in China underlines the need of a quick action in order to avoid from tremendous environmental and social impacts.

Open Wire burning, landfill and primitive printed circuit boards treatment in China (http://ewasteguide.info)

In order to tackle the problem the StEP (Solving the E-waste Problem) initiative, initiated by the United Nations University (UNU), launched the “Best of 2 Worlds” (Bo2W) project. The project aims the combination of Chinese strengths with the European ones in order to give a sustainable alternative to the recent recycling system. The approach is to combine the manual dismantling, which stands for pure fractions and little material losses, with the best available technology (BAT) for the further processing of complex material.
 
“Best of 2 worlds”: Manual dismantling in China and precious/special metal refining in EU

The main aim of this study is to optimize the interface between manual pre-processing and further treatment by assessing the optimal dismantling depth. The focus lies on desktop PCs, as well as on sublevel devices (drives and power supply). Different scenarios under an environmental and economic perspective are assessed and further compared to a mechanical pre-processing.

The determination of the environmental impact is based on Life Cycle Assessment (LCA), while for the economic analysis the Life cycle Costing (LCC) methodology is applied. Further the two dimensionally assessed scenarios are interpreted according to their total eco-efficiency.

The results show that the environmental weighted recycling percentages are increasing from 70% to 84% when the complete manual-dismantling scenario is compared with the shredding. The further processing is identified to contribute most to the total environmental gain, while also causing a minor environmental burden. The pre-processing and the transportation are negligible under an environmental perspective. For one desktop PC, the net financial result increases from 4.4€ per unit revenue towards 8.3 € revenue, including all costs for collection, sorting, transport and further treatment under average metal prices as of February 2007. The partial dismantling (drives, main boards and encasing) of the desktop PC show, with a recycling rate of 79% and a net revenue of 5.9 € per unit, values in between. Therefore this study concludes that high level manual dismantling is economically and environmentally preferable to a mechanical pre-processing under Chinese settings.

Contact:
Simon Gmünder
Schäfliwiese 13
9306 Freidorf
Tel: 078 616 02 83
simon.gmuender@gmail.com

Partner in China:

Taizhou Chiho Tiande
Mr. Stephan van Ooyen
No. 1 North Road, Industrial Zone of Metal Recycling,
Fenginag, Luqiao, Zhejiang, P.R.C. 318054
Tel: +86-576-2680999
chiho.tiande@gmail.com