Browsing by Author "Vanegas, Paul"

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Closed loop recycling of plastics containing flame retardants
(2014-03) Peeters, Jef R.; Vanegas, Paul; Tange, Lein; Van Houwelingen, Jan; Duflou, Joost R.
Annually 2.7 million tonnes of plastics containing Flame Retardants (FRs) are globally discarded in Waste Electrical and Electronic Equipment (WEEE). Little is known on the feasibility of closing material loops for FR plastics. Therefore, series of experiments were set up to analyze the feasibility of separating plastics containing FRs from one specific product category, namely End-of-Life (EoL) Liquid Crystal Display (LCD) TVs. The characterization of the housings of this waste stream indicated a concentration of 18 wt% Bromine based (Br) FRs and 31 wt% Phosphor based (P) FRs, the remainder not containing FRs. With practical tests it was demonstrated that, after disassembly and plastic identification, the co-polymer poly-carbonate (PC)/acrylonitrile-butadiene-styrene (ABS) containing PFR can be recycled in a closed loop system. Based on the determined plastic density distributions and separation efficiencies of optical sorters, a purity of 82% was calculated for PFR PC/ABS separated from EoL LCD TVs after size-reduction (shredding). Performed miscibility tests indicated that for this fraction at least a factor 10 dilution with virgin material is required. In addition, higher waste volumes are required for a size-reduction based treatment to become economically viable and technical challenges still need to be faced, whereas closed loop recycling of PFR PC/ABS from the current waste stream of EoL LCD TVs of different brands in a disassembly based treatment is found to be technically feasible and economically viable under European boundary conditions.
Finding sites meeting compactness and on- and off-site suitability criteria in raster maps
(2010-02-16) Vanegas, Paul; Wijffels, Anja; Cattrysse, Dirk
This paper presents an evaluation of the Heuristic for Locating Cells (HLC) for identifying optimal sites in raster maps. The optimal sites are the result of a trade-off between the on-site suitability of individual cells, their spatial configuration, and their off-site impact at the watershed outlet. The evaluation is targeted to a case of reforestation in two sub-basins within the Tabacay catchment in the southern Andes of Ecuador. The case is set up to locate a predefined number of cells 1) forming a compact patch, 2) minimizing sediment reaching the watersheds outlet, and 3) maximizing cell-specific performance, i.c. carbon sequestration and monetary income as a result of reforestation with pine trees. The evaluation confirms that the heuristic is capable of identifying high quality compact patches of cells with maximal on-site performance while minimizing sediment delivery.
Synergizing industrialized and developing countries to improve resource recovery for e-waste: case study Belgium - Kenya
(2014) Vanegas, Paul; Peeters, Jef R.; Plessers, Frank; Cattrysse, Dirk; Duflou, Joost R.
Due to high labor costs, e-waste recycling companies in industrialized countries increasingly adopt destructive mechanical pre-processing based treatments. These processes perform poorly for precious metals and plastics due to material incompatibility and increased entropy, resulting in low effective recycling efficiencies for these material categories. In developing countries most e-waste treatments consist of manual dismantling, followed by primitive refining techniques, which is not only inefficient, but also poses a serious threat to the environment. This article assesses, from an economic and environmental perspective, a cooperation scenario between Belgium and Kenya in which manual dismantling and state of the art metal refining techniques for recycling computers are combined. Findings show that international cooperation could offer a more sustainable solution, yet measures must be taken to avoid the “cherry picking” of valuable components and environmentally unsound disposal of the remaining parts.