ABSTRACT

One of the after-effect of the technological innovation is that the products become obsolete more and more quickly. This happens, for example, to the Electrical and Electronic Equipment (EEE); on this point, the European Parliament and the Council of the European Union recently adopted two directives: the 2002-95-CE, about the content of hazardous substances in the EEE, and the 2002-96-CE, about the Waste Electrical and Electronic Equipment (WEEE).
This last one, in particular, provides for high percentages of recovery, reuse and recycling of the components, materials and substances contained in the WEEE. Among the equipment belonging to the EEE category, there are the TV sets and the monitors of the personal computers; each of them contains a cathode ray tube (CRT), that is about the 60-65% in weight. The 85% in weight of the CRT is made of glass, which is of two typologies: panel glass and funnel glass, respectively about the two third and the one third in weight.

The aim of this study is to support and to complete, with environmental (and, as an estimate, economical) evaluations, the research developed by the "Dipartimento di Ingegneria dei Materiali e dell'Ambiente" of the University of Modena and Reggio Emilia in collaboration with the Province of Reggio Emilia, Tred Carpi S.r.l. (MO) (a firm, which treats end-of-life durable goods) and Colorveggia Reire S.r.l. (RE) (a ceramic glaze producer).

The research successfully experimented a new open-loop recycling of the panel glass, which can be introduced in the composition of a ceramic glaze (produced by Colorveggia Reire S.r.l.), in a percentage up to 30%, instead of one or more frits; this is a valuable alternative to the closed-loop recycling currently followed by Tred Carpi S.r.l. (that sells the glass to Schott, a German firm, which uses it to produce new glass of the same type).

The study was developed following the LCA (Life Cycle Assessment) methodology, using the SimaPro 5.0 software and choosing the Eco-Indicator 99 as evaluation method. It considers three damage categories of potential environmental impacts (each grouping several impact categories together): Human Health, Ecosystem Quality and Resources. In addition to these categories, two more were introduced: Energy and Cost; they are considered only in the first phases of the analysis, in which the potential impact is valued in each category, but not in the final one, when a single value of the total potential environmental impact is given (in Points).

Among the analysis we have done, the most important are:

• the comparison between the production (by Colorveggia Reire S.r.l.) of the standard glaze and the production of the same kind of glaze, in which the panel glass is used, in a percentage of 30%, instead of one or more frits;
• the comparison between two ways of recycling the panel glass (deriving from the CRTs treated by Tred Carpi S.r.l): the open-loop one, for the production of the same type of glass (by Schott) and the closed-loop one, for the production of a ceramic glaze (by Colorveggia Reire S.r.l.).

The first comparison showed that introducing panel glass, in a percentage of 30%, instead of one or more frits, the potential environmental impact decreases of the 36% (from 0,0814 Pt/kg to 0,0521 Pt/kg) and, in particular, of the: 53% in Human Health (from 0,0327 Pt/kg to 0,0154 Pt/kg), 31% in Ecosystem Quality (from 0,0024 Pt/kg to 0,00166 Pt/kg) and 24% in Resources (from 0,0462 Pt/kg to 0,035 Pt/kg); moreover, also the costs decrease of about the 30% (it's an estimate value).

The results also showed that in the experimented open-loop recycling of the panel glass, compared to the closed-loop one, the avoided potential environmental impact, that is a negative value, increases (in absolute value) from 0,0539 Pt/kg to 0,1 Pt/kg and, in particular: from 0,00494 Pt/kg to 0,0585 Pt/kg in Human Health and from 0,000426 Pt/kg to 0,00321 Pt/kg in Ecosystem Quality. On the contrary, in Resources, it decreases (in absolute value) from 0,0485 Pt/kg to 0,0384 Pt/kg. As for the costs (estimated values), they decrease too.