Sorption of phenols: influence of groundwater pH and of soil organic carbon content

Physical and chemical properties of soil, groundwater and pollutants deeply influenced the type and the strength of sorption phenomena involving hydrophobic organic contaminants: Soil fraction of organic carbon (foc) and cation exchange capacity, groundwater pH and pollutants hydrophobicity were with undoubtedly the predominant issues. Approach: In this study an experimental study of the sorption of phenol and 2-nitrophenol on three soils was performed considering three initial pH values, with the aim to evaluate the soil/pollutant interactions as a function of the relative abundance of the neutral contaminants and phenolate species and of the solid phase properties. Results: The considered soil samples (a silty clay, a silt and a sand coming from northern Italy) underwent to a physical and chemical characterization: Particle-size, mineralogical and chemical analyses were performed. The experimental data coming from some batch tests, carried employing aqueous phases containing different concentrations of phenol and 2-nitrophenol at initial pH values equal to 4, 7 and 10, were fitted by means of several isotherm models. Three Dual Mode Models (DMM), employing different isotherm models to represent the sorption of the neutral and the anionic species of the pollutants, were evaluated by the researchers to simulate the sorption of phenol and 2- nitrophenol in the examined conditions. Conclusion: The soil/contaminant interaction mechanisms determining the isotherm shapes were discussed: foc appeared to be the main issue, although the nitrogroup was able to promote sorption. In all considered soil samples and at all initial pH values, the highest foc (found in the silty soil) and the presence of the nitro-group determined the highest amounts of pollutant transferred on the solid phase. The two DMMs proposed by the researchers, implying nonlinearity, showed a higher reliability in simulating experimental data compared to a DMM based on linear sorption isotherms. Main sorption mechanisms were controlled by the partitioning of neutral pollutants in soil organic matter, but also the interactions between the pollutants, both in phenolate and in neutral forms and the soil mineral surface played a primary rol

Strategies for the enhancement of automobile shredder residues (ASRs) recycling: results and cost assessment

With reference to the European regulation about the management of End-of-Life Vehicles (ELVs), Directive 2000/53/EC imposes the achievement of a recycling target of 85%, and 95% of total recovery by 2015. Over the last few years many efforts have been made to find solutions to properly manage the waste coming from ELVs with the aim of complying with the targets fixed by the Directive. This paper focuses on the economical evaluation of a treatment process, that includes physical (size and density), magnetic and electrical separations, performed on the light fraction of the Automobile Shredder Residue (ASR) with the aim of reducing the amount of waste to dispose of in a landfill and enhancing the recovery of valuable fractions as stated by the EU Directive. The afore mentioned process is able to enhance the recovery of ferrous and non-ferrous metals of an amount equal to about 1% b.w. (by weight) of the ELV weight, and to separate a high energetic-content product suitable for thermal valorization for an amount close to (but not higher than) 10% b.w. of the ELV weight. The results of the economical assessment led to annual operating costs of the treatment ranging from 300,000 €/y to 350,000 €/y. Since the considered plant treats about 13,500 metric tons of ASR per year, this would correspond to an operating cost of approximately 20 - 25 €/t. Taking into account the amount and the selling price of the scrap iron and of the non magnetic metal recovered by the process, thus leading to a gain of about 30 €/t per ton of light ASR treated, the cost of the recovery process is balanced by the profit from the selling of the recovered metals. On the other hand, the proposed treatment is able to achieve the fulfillment of the targets stated by Directive 2000/53/EC concerning thermal valorization and reduce the amount of waste generated from ELV shredding to landfil

Assessment of Microplastics Distribution in a Biological Wastewater Treatment

Full-scale wastewater treatment facilities are not able to prevent microplastics (MPs) from discharging into natural waters and they are also associated with the land application of the sludge. This study evaluates the distribution of microfibers (MFs) in a lab-scale sequencing batch reactor (SBR) fed by synthetic wastewater (SW) for 93 days. The MFs were analyzed through optical microscopy in the mixed liquor (ML) and the effluent, and sulfuric acid digestion was applied to discriminate between natural and synthetic MFs (i.e., MPs). The results of the optical microscopy analyses were further validated through FTIR spectroscopy. A model describing the evolution over time of the MF concentration in the ML was created, accounting for the MFs entering the system through the SW and atmospheric deposition. The ratio between the MF concentration in the ML and the effluent was 1409   781, demonstrating that MFs settle with the sludge. Consistently, in the ML, 64.9% of the recovered MFs were smaller than 1000 μm (average size 968 μm), while in the effluent, 76.1% of MFs were smaller than 1000 μm (average size 772 μm). Overall, 72% of MFs recovered from the ML were natural fibers and sulfuric acid digestion was successful in eliminating the natural MFs

Review of lithium-ion batteries’ supply-chain in Europe: Material flow analysis and environmental assessment

European legislation stated that electric vehicles’ sale must increase to 35% of circulating vehicles by 2030, and concern is associated to the batteries’ supply chain. This review aims at analysing the impacts (about material flows and CO2 eq emissions) of Lithium-Ion Batteries’ (LIBs) recycling at full-scale in Europe in 2030 on the European LIBs’ supply-chain. Literature review provided the recycling technologies’ (e.g., pyro- and hydrometallurgy) efficiencies, and an inventory of existing LIBs’ production and recycling plants in Europe. European production plants exhibit production capacity adequate for the expected 2030 needs. The key critical issues associated to recycling regard pre-treatments and the high costs and environmental impacts of metallurgical processes. Then, according to different LIBs’ composition and market shares in 2020, and assuming a 10-year battery lifetime, the Material Flow Analysis (MFA) of the metals embodied in End of Life (EoL) LIBs forecasted in Europe in 2030 was modelled, and the related CO2 eq emissions calculated. In 2030 the European LIBs’ recycling structure is expected to receive 664 t of Al, 530 t of Co, 1308 t of Cu, 219 t of Fe, 175 t of Li, 287 t of Mn and 486 t of Ni. Of these, 99% Al, 86% Co, 96% Cu, 88% Mn and 98% Ni will be potentially recovered by pyrometallurgy, and 71% Al, 92% Co, 92% Fe, 96% Li, 88 % Mn and 90% Ni by hydrometallurgy. However, even if the recycling efficiencies of the technologies applied at full-scale are high, the treatment capacity of European recycling plants could supply as recycled metals only 2%-wt of the materials required for European LIBs’ production in 2030 (specifically 278 t of Al, 468 t of Co, 531 t of Cu, 114 t of Fe, 95 t of Li, 250 t of Mn and 428 t of Ni). Nevertheless, including recycled metals in the production of new LIBs could cut up 28% of CO2 eq emissions, compared to the use of virgin raw materials, and support the European batteries’ value chain

Low-cost and environmentally friendly physic-mechanical pre-treatments to recycle lithium iron phosphate cathodes

Recycling Lithium Iron Phosphate (LFP) batteries is challenging, as their low economic value hinders the profitability of full-scale processes. Optimized pre-treatments are crucial for the overall efficiency and economic profitability of recycling processes. This study explored chemicals-free physic-mechanical pre-treatment processes aimed to detach waste LFP cathodes (production scraps and end-of-life, EoL) from aluminium current collectors. The technical performances of ultrasounds (35 kHz, in water at 25 °C for 5, 15, 30 min), ball milling (840–1080 rpm for 8, 16, 24 min), and thermal treatment (30 min at 200, 250, 300, 350,°C) coupled with ball milling (840 rpm for 5 min) have been compared. Environmental impacts and economic cost were calculated based on energy demand. The highest separation efficiency achieved were 95 ± 5% for Li, 99 ± 6% for Fe, and 80 ± 3% for P in scrap cathodes, treated at 200 °C for 30 min and ball milled at 840 rpm for 5 min; 93 ± 15% for Li, 97 ± 21% for Fe and 82 ± 20% for P in EoL cathodes, treated at 250 °C for 30 min and ball milled. The global warming impacts were: 3.33 ± 0.55 kg CO2 eq/kg of detached cathode for scraps and 3.08 ± 0.25 kg CO2 eq/kg for EoL cathodes; the costs were 1.45 ± 0.24 €/kg of detached cathode for production scraps samples and 1.34 ± 0.11 €/kg for EOL samples. In conclusion, chemicals-free mechanical detachment was effective both for production scraps and EoL cathodes, while thermal treatment was especially beneficial for EoL cathodes, and reducing milling time improved the environmental impacts and costs of the pre-treatment processes

Recovery of Waste Polyurethane from E-Waste. Part II. Investigation of the Adsorption Potential for Wastewater Treatment

This study explored the performances of waste polyurethane foam (PUF) derived from the shredding of end-of-life refrigerators as an adsorbent for wastewater treatment. The waste PUF underwent a basic pre-treatment (e.g., sieving and washing) prior the adsorption tests. Three target pollutants were considered: methylene blue, phenol, and mercury. Adsorption batch tests were performed putting in contact waste PUF with aqueous solutions of the three pollutants at a solid/liquid ratio equal to 25 g/L. A commercial activated carbon (AC) was considered for comparison. The contact time necessary to reach the adsorption equilibrium was in the range of 60–140 min for waste PUF, while AC needed about 30 min. The results of the adsorption tests showed a better fit of the Freundlich isotherm model (R2 = 0.93 for all pollutants) compared to the Langmuir model. The adsorption capacity of waste PUF was limited for methylene blue and mercury (Kf = 0.02), and much lower for phenol (Kf = 0.001). The removal efficiency achieved by waste PUF was lower (phenol 12% and methylene blue and mercury 37–38%) compared to AC (64–99%). The preliminary results obtained in this study can support the application of additional pre-treatments aimed to overcome the adsorption limits of the waste PUF, and it could be applied for “rough-cut” wastewater treatment

Environmental Assessment of Lithium-Ion Battery Lifecycle and of Their Use in Commercial Vehicles

This review analyzed the literature data about the global warming potential (GWP) of the lithium-ion battery (LIB) lifecycle, e.g., raw material mining, production, use, and end of life. The literature data were associated with three macro-areas—Asia, Europe, and the USA—considering common LIBs (nickel manganese cobalt (NMC) and lithium iron phosphate (LFP)). The GWP (kgCO2eq/kg) values were higher for use compared to raw material mining, production, and end of life management for hydrometallurgy or pyrometallurgy. Considering the significant values associated with the use phase and the frequent application of secondary data, this study also calculated the GWP of LIBs applied in public urban buses in Turin, Italy. The 2021 fleet (53% diesel, 36% natural gas, and 11% electric buses) was compared to scenarios with increasing shares of hybrid/electric. The largest reduction in CO2eq emissions (−41%) corresponded to a fleet with 64% electric buses. In conclusion, this review highlighted the bottlenecks of the existing literature on the GWP of the LIB lifecycle, a lack of data for specific macro-areas for production and use, and the key role of public transportation in decarbonizing urban areas

The Flavours of Coffee Grounds: the coffee waste as accelerator of new local businesses

Annual generation of Spent Coffee Grounds (SCG) is estimated around six million tonnes per year. They currently do not have a commercial value and are disposed of in landfills or as compost. Systemic Design approach developed by Politecnico di Torino (Department of Architecture and Design) wants to provide a holistic vision in which these productions are linked together through relationships, output and input, flows of energy and materials, in order to make the SCG recovery activity complex, with almost no waste. This research studies how to make real and profitable a system that values this waste considering the local condition

Assessment tools for disposable and long durability products

The current market situation is characterized by planned obsolescence. It warns the need to design in a more efficiently way, by optimizing the recycle and disassembly operations and lowering the impact on the environment of all kind of products, from the easiest to the most complex ones. This paper focuses on short-lived and long durability products by analyzing them respectively according to the methodologies developed by the Observatory of EcoPack (OEP) and the Design by Components (DC) that share the same general framework and scenario. For disposable products, i.e. packaging, the analysis was carried out with a comparative analysis on components and communication, up to the definition of guidelines for a specific productive sector. Regarding the long durability goods, i.e. household appliances, the analysis is done according to the DC, in which the complex products are simplify to a function-essential structure. This is the starting point for a new design of complex goods focused on disassembly and maintenance. These two methodologies are able to provide useful tools for designing and innovating, through a scientific quali-quantitative analysis on products that are currently on the market