2002–2022: 20 years of e-waste regulation in the European Union and the worldwide trends in legislation and innovation technologies for a circular economy

Waste Electrical and Electronic Equipment (WEEE or e-waste) has emerged as a formidable global waste stream, reflecting the mounting demand for technology in our interconnected world. Over the past two decades, besides a world facing a rapid digital, e-mobility, and green energy transition, there has been a growing recognition across the globe, among both society and industries, regarding the hazards and opportunities linked to e-waste management. This collective consciousness has driven the adoption of best practices, including the implementation of circular economy (CE) models, fostering environmentally sustainable production and recycling processes. With a rate of around the 72% of the global population (81 countries) reached by specific regulations by 2023, this review explores the evolving landscape of international legislation and emerging technologies designed for e-waste prevention and valorization, emphasizing low-environmental impact and sustainability. Despite a prolific scientific community (papers published on e-waste grew over 1000 times in the period 2002–2022) and the rise in good practices in different countries, the modest increase of innovation patents (rate of around 50% increase) and the limited number of industrially established innovation processes demonstrates that while the advancing technologies are promising, they remain in an early, embryonic stage. This paper offers a concise review of life cycle assessments from existing literature to underpin the technological advancements discussed. These assessments provide insights into the reduced environmental footprint of various innovative processes aimed at enhancing the circular economy and incorporating them into the emerging concept of safe- and sustainable-by-design. Meanwhile, global e-waste production rose from an estimated 34 Mt in 2010 to 62 Mt in 2022, while documented proper collection and recycling only increased from 8 Mt to 13.8 Mt over the same period. This shows that e-waste generation is growing nearly five times faster than formal recycling. Furthermore, if waste management activities remain at 2022 levels, a projected economic (benefit – costs) deficit of 40 billion USD is expected by 2030. It is time for communities to reverse the trend by expanding good practices and implementing technology-economic-environment sustainable and efficient circular economy models

2002–2022: 20 years of e-waste regulation in the European Union and the worldwide trends in legislation and innovation technologies for a circular economy

Waste Electrical and Electronic Equipment (WEEE or e-waste) has emerged as a formidable global waste stream, reflecting the mounting demand for technology in our interconnected world. Over the past two decades, besides a world facing a rapid digital, e-mobility, and green energy transition, there has been a growing recognition across the globe, among both society and industries, regarding the hazards and opportunities linked to e-waste management. This collective consciousness has driven the adoption of best practices, including the implementation of circular economy (CE) models, fostering environmentally sustainable production and recycling processes. With a rate of around the 72% of the global population (81 countries) reached by specific regulations by 2023, this review explores the evolving landscape of international legislation and emerging technologies designed for e-waste prevention and valorization, emphasizing lowenvironmental impact and sustainability. Despite a prolific scientific community (papers published on e-waste grew over 1000 times in the period 2002–2022) and the rise in good practices in different countries, the modest increase of innovation patents (rate of around 50% increase) and the limited number of industrially established innovation processes demonstrates that while the advancing technologies are promising, they remain in an early, embryonic stage. This paper offers a concise review of life cycle assessments from existing literature to underpin the technological advancements discussed. These assessments provide insights into the reduced environmental footprint of various innovative processes aimed at enhancing the circular economy and incorporating them into the emerging concept of safe- and sustainable-by-design. Meanwhile, global e-waste production rose from an estimated 34 Mt in 2010 to 62 Mt in 2022, while documented proper collection and recycling only increased from 8 Mt to 13.8 Mt over the same period. This shows that ewaste generation is growing nearly five times faster than formal recycling. Furthermore, if waste management activities remain at 2022 levels, a projected economic (benefit – costs) deficit of 40 billion USD is expected by 2030. It is time for communities to reverse the trend by expanding good practices and implementing technology-economic-environment sustainable and efficient circular economy models.Environmental Biolog

Combined use of reactive barrier and electrokinetics for remediation of Cr contaminated soil

A reactive barrier (RB) of transformed red mud (TRM), a by-product of the refinement of bauxite in alumina production, was fitted adjacent to the anode of an electrokinetic (EK) system with the aim of enhancing removal and favouring entrapment of chromium added to a low permeability clayey soil. The innovative study focused on evaluation of the synergic interaction between the EK system and the RB, and of efficiency when compared to traditional EK remediation. The results obtained underlined the successful outcome of treatment. In presence of the TRM RB, 19.4% wt. of total Cr content was detected in the anolyte and 20.6% wt. trapped in the anodic RB after 6 days, versus 6.6% wt. in the anolyte and 8.8% wt. in the soil adjacent to the anode following the control run without RB. On increasing duration of treatment up to 12 days, 60.8% wt. of total initial Cr was found in the anolyte and 25.5% wt. trapped in the RB, versus 9.1% wt. and 5.3% wt., respectively, after a control run of the same duration. Finally, on increasing the mass of TRM in the RB, 60.6% wt. of initial Cr content was found to have accumulated in the RB, with Cr being completely absent from the anodic chamber

REUSE OF BIOMASS ASH AS AN ADDITIVE IN THE COMPOSTING PROCESS

This work investigated the effects of using selected types of biomass combustion ash as an additive in the composting process. An experimental campaign was conducted where source separated organic fractions of municipal waste was mixed with 0%, 2%, 4% and 8% (w/w) of biomass ash. Both the composting process and the final compost quality were positively influenced by ash addition. In the ash-amended composting admixtures a higher volatile solids degradation and enhanced biological stability were found, because ash were found to be effective as physical conditioner. Improved humification of the organic matter, better germination performances and higher total Ca, Mg, K and P contents were observed in the ash-amended composts comparing to the unamended one. In addition, nutrients fraction readily availability for plants was favored by ash addition with regards to Ca, Mg and K. Nitrogen content in the final composts was reduced by ash addition, but the Ctotal/Ntotal ratio was not negatively affected. The content of heavy metals and their solubility, that is regarded as the main environmental disadvantage when using combustion ash as additive, did not affect the final compost quality negatively. On the other hand, some controversial effects were observed, such as higher pH and electrical conductivity levels comparing to the unamended one. Moreover, higher temperature values and lower moisture levels were observed at the beginning of the composting process in the ash-amended composting admixture

Energy recovery from one- and two-stage anaerobic digestion of food waste

Abstract One- and two-stage anaerobic digestion of food waste aimed at recovering methane (CH4) and hydrogen and methane (H2 + CH4), respectively, were compared in order to assess the potential benefits from the two-stage process in terms of overall energy recovery. Results suggest that a two-stage process where the first reactor is properly operated in order to achieve a significant net hydrogen production, may display a 20% comparatively higher energy recovery yield as a result, mainly, of enhanced methane production as well as of the associated hydrogen production. The highest methane production of the two-stage process was due to improved hydrolysis and fermentation of food waste, with increased amounts of volatile fatty acids being readily available to methanogenesis

Co-composting of municipal biowaste and biomass power plant ash: effect on the biological process and the final compost quality

In this work the use of selected types of biomass combustion ash as an additive in the composting process was studied and discussed. A composting experimental campaign was conducted in four pilot-scale composters where 0%, 2%, 4% and 8% (w/w) of biomass ash were added to the organic fraction of the municipal solid waste mixed with wood prunings, that served as bulking agent. Biomass ash influenced both the composting process and the final product quality positively. The volatile solids reduction and the stability of the final composts, the latter being measured by means of the oxygen consumption, were greatly enhanced, and the temperature rise at the early stage of the process was improved. The ash-amended composts were enriched in nutrients (Ca, Mg, K and P) and expected to be beneficial for the plant growth, as the germination tests showed. Some adverse effects were also observed, such as the higher pH and electrical conductivity in the ash-amended composts comparing to the unamended one. Also, moisture was greatly affected by ash addition, to an extent which required external control. As for the heavy metal content, that was expected to be the main disadvantage related to the ash use, it does not seem to constitute an environmental concern for the ash content considere