Recovery of Plastics from WEEE through Green Sink-Float Treatment.

Increasing demand for electrical and electronic equipment results in the generation of a rapidly growing waste stream, known by the acronym WEEE (waste electrical and electronic equipment). The purpose of this study was to evaluate the effectiveness of green sink-float treatment in sorting plastic polymers typically found in WEEE (PP, ABS, PA6, PS, and PVC). Molasses, a by-product of sugar bio-refining, was added in various concentrations to water to form solutions at different densities. The methodology was initially tested on virgin polymers; later, it was applied to plastics from a WEEE treatment plant. The polymers were characterised through near infrared spectroscopy (NIRS) and Fourier-transform infrared spectroscopy (FTIRS) analyses; the detection of any additives and flame retardants was conducted using the sliding spark technology (SSS2) and scanning electron microscope (SEM-EDX). The results showed that, for plastics from WEEE, the recovery efficiency was 55.85% for PP in a solution of tap water while the remaining part of PP (44.15%) was recovered in a solution of water to which 90% molasses was added. Furthermore, 100% recovery efficiency was obtained for PS and 93.73% for ABS in a solution of tap water with the addition of 10% w/v molasses. A recovery efficiency of 100% was obtained for PVC and 100% for PA6 in a solution consisting solely of molasses.

Environmental Sustainable Cement Mortars Based on Polyethylene Terephthalate from Recycling Operations.

The building and construction industry is a key sector behind the ecological transition in that it is one of the main responsible factors in the consumption of natural resources. Thus, in line with circular economy, the use of waste aggregates in mortars is a possible solution to increase the sustainability of cement materials. In the present paper, polyethylene terephthalate (PET) from bottle scraps (without chemical pretreatment) was used as aggregate in cement mortars to replace conventional sand aggregate (20%, 50% and 80% by weight). The fresh and hardened properties of the innovative mixtures proposed were evaluated through a multiscale physical-mechanical investigation. The main results of this study show the feasibility of the reuse of PET waste aggregates as substitutes for natural aggregates in mortars. The mixtures with bare PET resulted in less fluid than the specimens with sand; this was ascribed to the higher volume of the recycled aggregates with respect to sand. Moreover, PET mortars showed a high tensile strength and energy absorption capacity (with Rf = 1.9 ÷ 3.3 MPa, Rc = 6 ÷ 13 MPa); instead, sand samples were characterized by a brittle rupture. The lightweight specimens showed a thermal insulation increase ranging 65-84% with respect to the reference; the best results were obtained with 800 g of PET aggregate, characterized by a decrease in conductivity of approximately 86% concerning the control. The properties of these environmentally sustainable composite materials may be suitable for non-structural insulating artifacts.

Recycling of Contaminated Marine Sediment and Industrial By-Products through Combined Stabilization/Solidification and Granulation Treatment.

Stabilization/solidification (S/S) is becoming increasingly important, as it allows the remediation of contaminated sediments and their recovery into materials for civil engineering. This research proposes a cement-free cold granulation process for manufactured low-cost aggregates from marine sediments contaminated with organic compounds and metals. After the chemo-physical characterization of the study materials, two mix designs were prepared in a rotary plate granulator by adding two industrial by-products as geopolymer precursors, coal fly ash (CFA) and Blast Furnace Slag (BFS), but also alkaline activation solutions, water, and a fluidizer. The results indicated that sediments treated with mix 1 (i.e., with a higher percentage of water and fluidifier) represent the optimal solution in terms of metal leachability. The metal leachability was strictly influenced by aggregates' porosity, density, and microstructure. The technical performance (such as the aggregate impact value > 30%) suggested the use of granules as lightweight aggregates for pavement construction. The results indicated that cold granulation represents a sustainable solution to recycling contaminated marine sediments, CFA, and BFS into lightweight artificial aggregates.

The Improvement of Durability of Reinforced Concretes for Sustainable Structures: A Review on Different Approaches.

The topic of sustainability of reinforced concrete structures is strictly related with their durability in aggressive environments. In particular, at equal environmental impact, the higher the durability of construction materials, the higher the sustainability. The present review deals with the possible strategies aimed at producing sustainable and durable reinforced concrete structures in different environments. It focuses on the design methodologies as well as the use of unconventional corrosion-resistant reinforcements, alternative binders to Portland cement, and innovative or traditional solutions for reinforced concrete protection and prevention against rebars corrosion such as corrosion inhibitors, coatings, self-healing techniques, and waterproofing aggregates. Analysis of the scientific literature highlights that there is no preferential way for the production of "green" concrete but that the sustainability of the building materials can only be achieved by implementing simultaneous multiple strategies aimed at reducing environmental impact and improving both durability and performances.

Experimental Investigation on Environmentally Sustainable Cement Composites Based on Wheat Straw and Perlite.

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.

A review of the in-situ capping amendments and modeling approaches for the remediation of contaminated marine sediments.

Contaminated sediments can pose long-term risks to human beings and ecosystems as they accumulate inorganic and organic contaminants becoming a sink and source of pollution. Compared to ex-situ technologies (i.e., dredging activities and off site treatments), in-situ capping (ISC) intends to minimize contaminated sediment mobilization and impact into the water column whilst treating contamination. Literature shows that numerous types of ISC amendments in presence of both organic and inorganic pollutants are investigated, although a few are contributions whose experiments have been designed and conducted with a view to future engineering. Against this background of shortcomings, this review paper intends to investigate ISC reliability, applicability and its long-term effectiveness, by also comparing reactive and physical ISCs. Additionally, an examination of the main numerical simulations applied to ISC technology was carried out. We found that activated carbon and organoclay resulted the most studied amendments for organically contaminated sediment, whereas biochar, clay minerals, and industrial-by products were more employed in presence of sediment contaminated by metal(loids). There is no better ISC system in absolute terms, since technological performance depends on many factors and only a few experimental investigations included a long-term modeling phase to predict ISC long-term efficiency. Most of numerical models included simplified transport equations based on diffusion and adsorption, and the goodness of fitting between experimental and modeled data was not always computed. The review finally discusses new research directions such as the need for long-term applications on field-scale and cap effectiveness in presence of site-specific tidal forces and currents.

A holistic DPSIR-based approach to the remediation of heavily contaminated coastal areas.

This paper proposes a holistic approach to connect anthropogenic impacts to environmental remediation solutions. The eDPSIR (engineered-Drivers-Pressures-States-Impacts-Responses) framework aims at supporting the decision-maker in designing technological solutions for a contaminated coastal area, where the natural matrices need to be cleaned up. The eDPSIR is characterized by cause-effect relationships that are operationally implemented through three multidisciplinary toolboxes: (i) Toolbox 1, to connect driving forces with pressures, classifying the state of the system and allowing the identification of target contaminants and the extent of contamination; (ii) Toolbox 2, to quantify bioaccumulation also by identifying corresponding areas; (iii) Toolbox 3, to identify the most suitable remediation solutions for previously identified contaminated areas, named contamination scenarios. The eDPSIR was calibrated on the case study of the Mar Piccolo in Taranto (Southern Italy), one of the most complex and polluted areas in Europe. While the consolidated DPSIR allows for a strategic response by limiting the use of contaminated areas or reducing upstream pressures, the eDPSIR made it possible to structure with a semi-quantitative logic the problem of assisting the decision-makers in choosing the optimal technological remediation responses for each sediment scenario of contamination (heavy metal; organic compounds; mixed). Assisted natural attenuation was identified as the best remediation technology in terms of treatment effectiveness and smallest amount of impacts involved in the project actions. However, considering the scenario of mixed contamination, in-situ reactive capping reached a good rank with a value of the composite indicator equal to 99.5%; thermal desorption and stabilization/solidification recorded a value of 94.1% and 84.6%, respectively. The application of these toolboxes provides alternative means to interpret, manage, and solve different cases of global marine contaminated sites.

Contaminated marine sediment stabilization/solidification treatment with cement/lime: leaching behaviour investigation.

Among ex situ remediation technologies, stabilization/solidification (S/S) provides for the addition of a binder to dredged materials in order to chemically immobilise the contaminants and improve mechanical behaviour of sediments. The simplest form of treatment is obtained by the addition of Portland cement or lime (calcium oxide), although other additives such as adsorbents may be added. Nevertheless, the success of the S/S treatment may be affected by the contaminants present or by the salt content in the water. In this study, experimental laboratory investigation was carried out on sediments carefully collected from the Mar Piccolo of Taranto in Southern Italy, contaminated by heavy metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs); the goal was to explore the effectiveness of S/S treatment by using Portland cement/lime as binders, monitoring over time (28 days) the leaching of the different mixtures of treated sediment. It is noted that the Mar Piccolo of Taranto is one of the sites of national interest subject to remediation by the Italian government. Once taken within the first meter under the sea floor by a team of experienced divers, the samples were stored at a controlled temperature, characterised in terms of grain size and physical-chemical characteristics and treated by S/S laboratory tests. The results indicate that the addition of binders increased the pH of the mixtures with a consequent leachability of different metals. The mobility of the metals appeared to be governed also by the curing time. The performance of the mixtures in terms of immobilised metals was influenced by the presence of organic contaminants (e.g. organic matter, PAHs and PCBs). As a lesson, high organic matter and fine-grained particles can negatively affect the effectiveness of the S/S treatment in terms of metal immobilisation.

Environmentally Sustainable Cement Composites Based on End-of-Life Tyre Rubber and Recycled Waste Porous Glass.

In this paper, environmentally sustainable cement mortars were prepared with end-of-life tyre rubber (TR) and recycled waste porous glass (PG) as aggregates in order to obtain lightweight products characterized by renewable and not-pretreated materials specifically for indoor applications. The secondary raw materials were added as partial and/or total replacement of the conventional sand aggregate. The resulting lightweight specimens were characterized by rheological, mechanical, thermal, microstructural and wettability tests. Fine tyre rubber aggregates affected the cohesiveness of the composites, as opposite to coarse tyre rubber and porous glass. The flexural and the compressive strengths of the porous glass samples were higher than the tyre rubber samples because of the higher stiffness and good adhesion of the glass to the cement paste as observed by microstructural observations. On the contrary, an unfavorable adhesion of the tyre aggregates to the cement paste was observed, together with discrete cracks after failure without separation of the two parts of the specimens. The latter result can explain the best results obtained by tyre rubber mortars in the case of impact compression tests where the super-elastic properties of the elastomeric material were evidenced by a deep groove before complete failure. Moreover, the thermal conductivity decrease of the lightweight porous TR and PG composites was in the range of ~80-90% with respect to the sand-based samples, which suggests that they can be used as plasters and masonries, and, in the case of tyre rubber specimens, outside applications are not excluded as observed from the wettability tests.

Alternating pure oxygen and air cycles for the biostabilization of unsorted fraction of municipal solid waste.

Biostabilisation is a process of treating the unsorted fraction of municipal solid waste (UFMSW) mechanically pre-treated. Although concepts such as circular economy would seem to limit biostabilization, several authors have recently described the advantages of biostabilization in regions where recycling systems are inadequate. In this perspective, the development of new MBT technologies is of considerable importance. The objective of the study was to evaluate the effects of the use of alternating air and oxygen cycles on the treated waste stability as well as on the quality of leachate and process gaseous emissions. Two Herhof biocells were prepared for this purpose. One implemented the conventional process and the other the "Air + O2" process. The biostabilization of the inlet UFMSW (3965 ±â€¯1965 mgO2/kgVS/h) resulted in a final product with a dynamic respirometric index almost equal in both processes. The mass balance indicated that of the 400 tons representing the input waste, 37.57% were biostabilized waste, 0.29% leachate and 62.14% CO2 and odours. However, the biostabilized waste was lower than that of the conventional process (equal to 40.18%). The Air + O2 system resulted in a shorter duration, increased production of leachate (although characterized by higher quality) and process gaseous emissions quality. The energy balance (20.3 kJ/kg per input waste) and cost analysis (80.0 €/ton per input waste) showed values equal or better to those of the conventional system. By contrast, weakness was in the O2 diffusion system. Although a life cycle analysis is necessary, the results highlighted the feasibility of the proposal especially for emergency situations.

On the geotechnical characterisation of the polluted submarine sediments from Taranto.

This paper reports the results of the first geomechanical laboratory experiments carried out on the polluted submarine clayey sediments of the Mar Piccolo in Taranto (South of Italy). The study had to face with extreme difficulties for the very soft consistency of the sediments and the contaminants. The mineralogy, composition and physical properties of the sediments were analysed, along with their compression and shearing behaviour. The investigation involved sediments up to about 20 m below the seafloor, along three vertical profiles in the most polluted area of the Mar Piccolo, facing the Italian Navy Arsenal. The experimental results were used to derive a preliminary geotechnical model of the site, necessary for the selection and design of the most sustainable in situ mitigation solutions. Moreover, the experimental data reveal that the clayey sediments of the most polluted top layer do not follow the classical geotechnical correlations for normally consolidated deposits. This seems to open interesting perspectives about the effects of pollutants on the geotechnical behaviour of the investigated sediments.

Appropriate management of cutaneous adverse events maximizes compliance with sorafenib treatment: a single-center experience.

AIMS: This report describes a positive experience of adverse event (AE) management of a multidisciplinary clinical team and 18 patients with late-stage renal cell carcinoma and hepatocellular carcinoma attending the Day Hospital Unit of the 'Centro Catanese di Oncologia Humanitas' (Italy) over a 2-year period. METHODS: The management strategy was based on preventive measures for reducing the development of cutaneous AEs, including pain, risk of infection and patient discomfort, while avoiding the discontinuation or the reduction of the sorafenib dosage. RESULTS: As of July 2011, eight patients were still under treatment with sorafenib; seven patients experienced cutaneous AEs and two reported severe cutaneous AEs. CONCLUSION: Our treatment approach seemed to reduce the incidence and/or severity of AEs, keeping patients in treatment, which is essential for good treatment outcomes.