Abstract
Modern products contain a wide range of substances. Some of them are hazardous, cause risks for human and environmental health, and impair the quality of future secondary resources produced by recycling. Ways must be explored to extract detrimental substances during recycling and direct them to safe final sinks. Final sinks can be end-of-pipe technologies (man-made sinks) or environmental media (natural sinks). The latter are limited in capacity and need to be protected against overloading. The paper presents a rationale for sinks in a circular economy, and supports decision-making regarding recycling materials with detrimental constituents. It is based on two case studies of regional flows of polycyclic aromatic hydrocarbons in spent asphalt pavements, and copper in waste flows. Applying a scenario approach, effective measures are discussed for circulating safe and high-quality materials while observing sink limitations. The results demonstrate the link between mass flows, quality of recycled material, and the need for final sinks. The optimization challenge of keeping cycles clean by costly measures for safe disposal of hazardous materials in sinks is discussed. Man-made sinks such as waste to energy plants and sanitary landfills are key for designing a circular economy that meets environmental and resource-oriented goals.
Highlights
The material turnover of modern economies is so high that future supply of raw materials is at risk in a long-term perspective
The intention of this article is neither to apply one of these evaluation methods nor to add a new method. It is to respect the phenomena of contaminated material cycles and to demonstrate the consequences of keeping material cycles clean. When it comes to more holistic strategies for avoiding contaminated material cycles, Sakai [16] suggested a “Clean, Cycle and Control” concept, and Brunner [17] added the need for final sinks to get rid of non-recyclable materials to keep the material cycles clean
80% of the polycyclic aromatic hydrocarbons (PAHs) will become destroyed by mineralization, 20% will remain in the cycle, and about 1% still ends up in sanitary landfills
Summary
The material turnover of modern economies is so high that future supply of raw materials is at risk in a long-term perspective. Carcinogenic substances contaminate the asphalt cycle [4, 5], brominated flame retardants and phalates contaminate the plastic cycle [6,7,8], mineral oils, bisphenol A, diethylhexyl phthalate contaminate the paper cycle [9, 10], heavy metals contaminate recyclable grit [11], or copper in scrap contaminates the steel cycle [12]. These case studies show that additional endeavours are needed to ensure the qualitative concern of keeping material cycles clean. Knapp, Allesch, Muller et al [13] presented a methodology to estimate the transfer of contaminants into recycling products, Rechberger and Brunner [14] proposed an entropy-based approach to consider quality aspects in material flows, and Rigamonti, Niero, Haupt et al [15] recommend to consider quality aspects of waste-derived materials in life-cycle
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
