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In the last twenty years, the European Union (EU) has enhanced Waste Management (WM) strategies toward Circular Economy (CE). Starting from the previous analysis carried out by Fabrizi and Sospiro (Waste Management in Europe: A Comparative Study of the main EU countries: Methodology and Evaluation of Local Waste Management System, Lambert Publisher, Saarbücken, Germany, 2017), this article analyses firstly EU Member States (MSs) Roadmap toward Sustainable Waste Management (SWM) and secondly to CE. The research relied on Kirchherr et al. (Kirchherr in Ecological Economics 150:264–272, 2018) study which identified four barriers to CE (cultural, regulatory, market failure, and technological). The regulatory framework has been analysed. Four case studies (France, FR, Germany, DE, Italy, IT, the Netherlands, NL) have been selected to investigate: criteria, methodologies, policies, implementation and outcomes on SWM at national level. In addition, given MSs coordination at EU level the research aimed at analysing whether is there any convergence in terms of policies and achievements. The study considered recent findings on CE, Eurostat data, and Eurostat Circular Material Use (CMU) indicator. The analysis revealed SWM positive results, which seem to confirm a certain degree of convergence between EU-MSs that consists in a positive cascade mechanism from advanced toward less advanced MSs. In spite of this, EU countries need a further step in order to close materials’ loops. Larger quantity of Secondary Raw Materials (SRMs) should return to manufacture, and this requires stronger intervention that goes beyond the waste sector. In light of this, the EU Commission recently entrusted the Joint Research Centre (JRC) to assess and compare the environmental impacts of alternative feedstock for plastic products. This reveals EU attempt to re-balance the intervention on CE, by striving new products’ design approaches.

Implementation of construction works on weak (e.g., compressible, collapsible, expansive) soils such as peatlands often is limited by logistics of equipment and shortage of available and applicable materials. If preloading or floating roads on geogrid reinforcement or piled embankments cannot be implemented, then soil stabilization is needed. Sustainable soil stabilization in an environmentally friendly way is recommended instead of applying known conventional methods such as pure cementing or excavation and a single replacement of soils. Substitution of conventional material (cement) and primary raw material (lime) with secondary raw material (waste and byproducts from industries) corresponds to the Sustainable Development Goals set by the United Nations, preserves resources, saves energy, and reduces greenhouse gas emissions. Besides traditional material usage, soil stabilization is achievable through various secondary raw materials (listed according to their groups and subgroups): 1. thermally treated waste products: 1.1. ashes from agriculture production; 1.2. ashes from energy production; 1.3. ashes from various manufacturing; 1.4. ashes from waste processing; 1.5. high carbon content pyrolysis products; 2. untreated waste and new products made from secondary raw materials: 2.1. waste from municipal waste biological treatment and landfills; 2.2. waste from industries; 3. new products made from secondary raw materials: 3.1. composite materials. Efficient solutions in environmental engineering may eliminate excessive amounts of waste and support innovation in the circular economy for sustainable future.

Driven by environmental concerns and aligned with the principles of the circular economy, urban plastic waste—including packaging materials, disposable items, non-functional objects, and industrial scrap—is increasingly being collected, recycled, and marketed as a potential substitute for virgin polymers. However, the use of recycled polymers introduces uncertainties that can significantly affect both the durability and the further recyclability of the resulting products. This paper demonstrates how spectroscopic analysis in the mid-infrared (MIR) and near-infrared (NIR) regions can be applied well beyond the basic identification of the main polymeric component, typically performed during the sorting stage of recycling processes. A detailed interpretation of spectral data, based on well-established correlations between spectroscopic response and material structure, enables the classification of recycled polymers according to specific physicochemical properties, such as chemical composition, molecular architecture, and morphology. In this context, infrared spectroscopy not only provides a reliable comparison with the corresponding virgin polymer references but also proves particularly effective in assessing the homogeneity of recycled materials and the reproducibility of their properties—factors not inherently guaranteed due to the variability of input sources. As a case study, we present a robust protocol for determining the polypropylene content in recycled polyethylene samples.

The aim of this paper is for the production of oils processed in refineries to come from the pyrolysis of real waste from the high plastic content rejected by the recycling industry of the Basque Country (Spain). Concretely, the rejected waste streams were collected from (1) a light packaging waste sorting plant, (2) the paper recycling industry, and (3) a waste treatment plant of electrical and electronic equipment (WEEE). The influence of pre-treatments (mechanical separation operations) and temperature on the yield and quality of the liquid fraction were evaluated. In order to study the pre-treatment effect, the samples were pyrolyzed at 460 °C for 1 h. As pre-treatments concentrate on the suitable fraction for pyrolysis and reduce the undesirable materials (metals, PVC, PET, inorganics, cellulosic materials), they improve the yield to liquid products and considerably reduce the halogen content. The sample with the highest polyolefin content achieved the highest liquid yield (70.6 wt.% at 460 °C) and the lowest chlorine content (160 ppm) among the investigated samples and, therefore, was the most suitable liquid to use as refinery feedstock. The effect of temperature on the pyrolysis of this sample was studied in the range of 430–490 °C. As the temperature increased the liquid yield increased and solid yield decreased, indicating that the conversion was maximized. At 490 °C, the pyrolysis oil with the highest calorific value (44.3 MJ kg−1) and paraffinic content (65% area), the lowest chlorine content (128 ppm) and more than 50 wt.% of diesel was obtained.

Metals are essential in our daily lives and have a finite supply, being simultaneously contaminants of concern. The current carbon emissions and environmental impact of mining are untenable. We need to reclaim metals sustainably from secondary resources, like waste. Biotechnology can be applied in metal recovery from waste streams like fly ashes and bottom ashes of municipal solid waste incineration (MSWI). They represent substantial substance flows, with roughly 46 million tons of MSWI ashes produced annually globally, equivalent in elemental richness to low-grade ores for metal recovery. Next-generation methods for resource recovery, as in particular bioleaching, give the opportunity to recover critical materials and metals, appropriately purified for noble applications, in waste treatment chains inspired by circular economy thinking. In this critical review, we can identify three main lines of discussion: (1) MSWI material characterization and related environmental issues; (2) currently available processes for recycling and metal recovery; and (3) microbially assisted processes for potential recycling and metal recovery. Research trends are chiefly oriented to the potential exploitation of bioprocesses in the industry. Biotechnology for resource recovery shows increasing effectiveness especially downstream the production chains, i.e., in the waste management sector. Therefore, this critical discussion will help assessing the industrial potential of biotechnology for urban mining of municipal, post-combustion waste.

PurposeA circular (bio)economy is sustained through use of secondary raw material and biomass feedstock. In life cycle assessment (LCA), the approach applied to address the impact of these feedstocks is often unclear, in respect to both handling of the recycled content and End-of-Life recyclability and disposal. Further, the modelling approach adopted to account for land use change (LUC) and biogenic C effects is crucial to defining the impact of biobased commodities on global warming.MethodWe depart from state-of-the-art approaches proposed in literature and apply them to the case of non-biodegradable plastic products manufactured from alternative feedstock, focusing on selected polymers that can be made entirely from secondary raw material or biomass. We focus on global warming and the differences incurred by recycled content, recyclability, LUC, and carbon dynamics (effects of delayed emission of fossil C and temporary storage of biogenic C). To address the recycled content and recyclability, three formulas recently proposed are compared and discussed. Temporary storage of biogenic C is handled applying methods for dynamic accounting. LUC impacts are addressed by applying and comparing a biophysical, global equilibrium and a normative-based approach. These methods are applied to two case studies (rigid plastic for packaging and automotive applications) involving eight polymers.Results and discussionDrawing upon the results, secondary raw material is the feedstock with the lowest global warming impact overall. The results for biobased polymers, while promising in some cases (polybutylene succinate), are significantly affected by the formulas proposed to handle the recycled content and recyclability. We observe that some of the proposed formulas in their current form do not fully capture the effects associated with the biogenic nature of the material when this undergoes recycling and substitutes fossil materials. Furthermore, the way in which the recycled content is modelled is important for wastes already in-use. LUC factors derived with models providing a combined direct and indirect impact contribute with 15–30% of the overall life cycle impact, which in magnitude is comparable to the savings from temporary storage of biogenic C, when included.ConclusionEnd-of-Life formulas can be improved by addition of corrective terms accounting for the relative difference in disposal impacts between the recycled and market-substituted product. This affects the assessment of biobased materials. Inclusion of LUCs effects using economic/biophysical models in addition to (direct) LUC already embedded in commercial datasets may result in double-counting and should be done carefully. Dynamic assessment allows for detailed modelling of the carbon cycle, providing useful insights into the impact associated with biogenic C storage.

This study evaluated the feasibility of reusing abandoned copper mine tailings (Cu tailings) as a precursor in the production of fly-ash-based alkali-activated materials (FA-AAMs). Two formulations were developed by combining FA and Cu tailings with a mixture of sodium silicate and sodium hydroxide as alkaline activators at room temperature (20 °C). Formulation G1 consisted of 70% Cu tailings and 30% fly ash (FA), whereas G2 included the same composition with an additional 15% ordinary Portland cement (OPC). The materials were characterized using X-ray fluorescence (XRF), -X-ray diffraction (XRD), field emission scanning electron microscopy with energy-dispersive spectroscopy (FESEM-EDS), and particle size analysis. While FA exhibited a high amorphous content (64.4%), Cu tailings were largely crystalline and acted as inert fillers. After 120 days of curing, average compressive strength reached 24 MPa for G1 and 41 MPa for G2, with the latter showing improved performance due to synergistic effects of geopolymerization and OPC hydration. Porosity measurements revealed a denser microstructure in G2 (35%) compared to G1 (52%). Leaching tests confirmed the immobilization of hazardous elements, with arsenic concentrations decreasing over time and remaining below regulatory limits. Despite extended setting times (24 h for G1 and 18 h for G2) and the appearance of surface efflorescence, both systems demonstrated good chemical stability and long-term performance. The results support the use of Cu tailings in FA-AAMs as a sustainable strategy for waste valorization, enabling their application in non-structural and moderate-load-bearing construction components or waste encapsulation units. This approach contributes to circular economy goals while reducing the environmental footprint associated with traditional cementitious systems.

Urban areas comprise less than 1% of the Earth’s land surface, yet they host more than half the global population and are responsible for the majority of global energy use and related CO2 emissions. Urbanization is increasing the speed and local intensity of water cycle exploitation, with a large number of cities suffering from water shortage problems globally. Wastewater (used water) contains considerable amounts of embedded energy and recoverable materials. Studies and applications have demonstrated that recovering or re-capturing water, energy, and materials from wastewater is a viable endeavor, with several notable examples worldwide. Reclaiming all these resources through more widespread application of effective technological approaches could be feasible and potentially profitable, although challenging from several points of view. This paper reviews the possibilities and technical opportunities applicable to the mining of resources within the urban water cycle and discusses emerging technologies and issues pertaining to resource recovery and reuse applications. The present and future sustainability of approaches is also discussed. Since sewage management issues are not “one size fits all”, local conditions must be carefully considered when designing optimal local resource recovery solutions, which are influenced not just by technology but also by multiple economic, geographical, and social factors.

The cement industry is a major contributor to global CO2 emissions, driving the research for sustainable alternatives. Olive biomass ash (OBA), a byproduct from burning all types of biomass from the olive tree, has emerged as a potential supplementary cementitious material (SCM). This study investigates the effects of incorporating olive pomace ash (OPA) as a partial cement substitute (0% to 50% by weight) on mortar properties over extended curing periods. Workability, compressive and flexural strengths, water absorption, and freeze–thaw resistance were evaluated. Up to 20% OPA replacement improved workability while maintaining acceptable strength and durability. Beyond this level, mechanical properties and frost resistance decreased significantly. Correlation analyses revealed strong relationships between flow time and wet bulk density (R2 = 0.93), an exponential relationship between 28-day compressive strength and water absorption (R2 = 0.87), and linear correlations between pre- and post-freeze–thaw mechanical properties (R2 ≥ 0.99 for both compressive and flexural strengths). The results demonstrate that optimal OPA incorporation enhances mortar performance without compromising structural integrity and provides a viable strategy for valorizing agricultural waste.

Environmentally sustainable cement mortars containing wheat straw (Southern Italy, Apulia region) of different length and dosage and perlite beads as aggregates were prepared and characterised by rheological, thermal, acoustic, mechanical, optical and microstructural tests. A complete replacement of the conventional sand was carried out. Composites with bare straw (S), perlite (P), and with a mixture of inorganic and organic aggregates (P/S), were characterised and compared with the properties of conventional sand mortar. It was observed that the straw fresh composites showed a decrease in workability with fibre length decrease and with increase in straw volume, while the conglomerates with bare perlite, and with the aggregate mixture, showed similar consistency to the control. The thermal insulation of the straw mortars was extremely high compared to the sand reference (85–90%), as was the acoustic absorption, especially in the 500–1000 Hz range. These results were attributed to the high porosity of these composites and showed enhancement of these properties with decrease in straw length and increase in straw volume. The bare perlite sample showed the lowest thermal insulation and acoustic absorption, being less porous than the former composites, while intermediate values were obtained with the P/S samples. The mechanical performance of the straw composites increased with length of the fibres and decreased with fibre dosage. The addition of expanded perlite to the mixture produced mortars with an improvement in mechanical strength and negligible modification of thermal properties. Straw mortars showed discrete cracks after failure, without separation of the two parts of the specimens, due to the aggregate tensile strength which influenced the impact compression tests. Preliminary observations of the stability of the mortars showed that, more than one year from preparation, the conglomerates did not show detectable signs of degradation.