Circularity in Practice: Review of Main Current Approaches and Strategic Propositions for an Efficient Circular Economy of Materials

This paper aims to summarize, propose, and discuss existing or emerging strategies to shift towards a circular economy of materials. To clarify the landscape of existing circular practices, a new spectrum is proposed, from product-based strategies, where entire products go through several life cycles without being reprocessed, to material-based approaches, extracting, recycling, and reprocessing materials from the waste flow. As refillable packaging does not lose any functionality or value, when re-used through many life cycles, product-based strategies are globally extremely efficient and must be promoted. It appears however that their implementation is only possible at the scale of individual products such as packaging containers, relying on the cooperation of involved companies and consumers. It appears more and more urgent to focus as well on a more systematic and flexible material-oriented scheme. The example of circular glass recycling is a success in many countries, and technologies become nowadays available to extend such practices to many other materials, such as rigid plastics. An ideal would be to aim at an economy of materials that would imitate the continuous material cycle of the biosphere. Technological and business strategies are presented and discussed, aiming at a relevant impact on circularity.

Investigating the Recycling Potential of Glass Based Dye-Sensitized Solar Cells—Melting Experiment

The effects of climate change are becoming increasingly clear, and the urgency of solving the energy and resource crisis has been recognized by politicians and society. One of the most important solutions is sustainable energy technologies. The problem with the state of the art, however, is that production is energy-intensive and non-recyclable waste remains after the useful life. For monocrystalline photovoltaics, for example, there are recycling processes for glass and aluminum, but these must rather be described as downcycling. The semiconductor material is not recycled at all. Another promising technology for sustainable energy generation is dye-sensitized solar cells (DSSCs). Although efficiency and long-term stability still need to be improved, the technology has high potential to complement the state of the art. DSSCs have comparatively low production costs and can be manufactured without toxic components. In this work, we present the world’ s first experiment to test the recycling potential of non-toxic glass-based DSSCs in a melting test. The glass constituents were analyzed by optical emission spectrometry with inductively coupled plasma (ICP-OES), and the surface was examined by scanning electron microscopy energy dispersive X-ray (SEM-EDX). The glass was melted in a furnace and compared to a standard glass recycling process. The results show that the described DSSCs are suitable for glass recycling and thus can potentially circulate in a circular economy without a downcycling process. However, material properties such as chemical resistance, transparency or viscosity are not investigated in this work and need further research.

Production or Consumption? Glass Beads from the Roman Villa of Aiano, Tuscany

Excavations in the Roman villa of Aiano yielded twenty glass beads, a pendant, and a glass-recycling furnace, originally interpreted as a bead workshop. This article re-assesses the evidence of bead making in light of new data obtained thanks to recent progress in archaeological glass studies. A detailed study of the typology, technology, and chemical composition of the beads clearly excludes local production. Instead, two different forming techniques, four different base glasses (Roman, HIMT, Foy 2.1 and Foy 2.1/HIMT), and numerous colouring and opacifying materials point to a well-established and extensive network of the Roman bead trade, in which Aiano evidently participated. The majority of the beads can be related to the monumentalization of the villa in the fourth to fifth century ad and represent a sample of the ornaments worn by its inhabitants.

Are Bottle Banks Sufficiently Effective for Increasing Glass Recycling Rates?

The Netherlands is a frontrunner in the EU regarding the circular economy. On a national scale, there are higher targets than the EU for different packaging materials as plastics, glass, paper/cartons, and aluminium. For glass, the government advocates a recycling rate of more than 90%. In 2017, the rate realised was 86%. To reach this 4% higher goal, the Human Environment and Transport Inspectorate wants to improve the collection infrastructure by increasing the number of bottle banks, with 800 by 2021. However, in the literature, an effectiveness analysis is lacking. Based on empirical evidence with data from 2007–2019, we show that increasing the number of bottle banks is not effective. Implementing a unit-based pricing system as a priced bag or container for unsorted waste can be more effective in achieving this goal, although this can have serious drawbacks.

Sustainable Glass Recycling Culture-Based on Semi-Automatic Glass Bottle Cutter Prototype

Humanity has developed recycling activities over time due to their benefits, the shortage of raw materials, or the footprint with regard to the environment. The absence of a recycling culture in Mexico has not allowed its development and growth despite the benefits. In 2012, Mexico only recycled less than 10% of urban solid waste. Most recycling activities are focused on plastic, paper, and cardboard products due to their prices in local markets. This article presents a semi-automated prototype focused on recycling glass bottles using the thermal shock phenomenon. It aims to develop a sustainable glass recycling culture by creating a new branch for the integral glass recycling process and a proposal base on Integrated Sustainable Waste Management (ISWM) and the Quintuple Helix Model. It helps to reduce waste and resource recovery from recycling and upcycling glass bottles. The products obtained from upcycling fulfill new uses and acquire new value, while glass leftovers continue the integral recycling process for glass. Additionally, this paper demonstrates the relation between the ISWM and the Quintuple Helix Model and the opportunity to implement the twelfth Sustainable Development Goal (SDG).

Characterization of Glass Powder from Glass Recycling Process Waste and Preliminary Testing

This work studies the possibility of incorporating different proportions of glass powder from the waste glass (rejected material called fine cullet) produced during the glass recycling process into the manufacturing of mortar and concrete. For this purpose, the material is characterized by its chemical composition and pozzolanic activity, and the shape and size of its particles are studied. It is then incorporated as a substitute for cement into the manufacturing of mortar and concrete at 25% and 40% of cement weight, and its effect on setting times, consistency, and mechanical strength is analyzed. Its behavior as a slow pozzolan is verified, and the possibility of incorporating it into concrete is ratified by reducing its cement content and making it a more sustainable material.

The Recycling of Waste Laminated Glass through Decomposition Technologies

Laminated glass is ever more frequently used nowadays. This applies to the automobile industry and the construction industry. In cars, this refers mostly to the front and rear windows, whereas in construction, technical safety glass is used for railings and window glass. The task of this type of glass is to provide sufficient resistance against mechanical impact and unpleasant weather conditions. At the same time, if it is damaged, it has to break into the smallest possible pieces, or, wherever possible, the glass should remain intact on the interlayer film to prevent shards from injuring people and animals in the immediate vicinity. The paper deals with the recycling of laminated glass, especially with the effective separation of glass (in the form of cullet) from the polyvinyl butyral (PVB) interlayer film. The experimental research is focused on the mechanical separation of glass from the interlayer film by vibration, and also on the chemical cleaning of PVB film in order to allow subsequent recycling of both materials. The results quantify the efficiency of mechanical separation in the form of weight loss of the sample of laminated glass and define the particle size distribution of glass cullet, which is an important parameter in the possibility of glass recycling. The research leads to a methodology proposal for the separation of glass and PVB film and the design of equipment for this method.