Energy and environmental assessment of plastic granule production from recycled greenhouse covering films in a circular economy perspective.

Plastic films can be considered as a high-value auxiliary material in agriculture with multiple important uses to fulfil, including covering films in greenhouse cultivation system. Such an application enables several benefits and, therefore, it is going through an important upsurge, especially in regions where protected crop cultivation is highly widespread. However, the increased demand for these covering films arouses concerns for their post-use treatment with regard to both the consumption of Non-Renewable Primary Energy (NRPE) resources and the emission of Greenhouse Gases (GHGs). Therefore, environmental analysis is needed to find and follow cleaner paths for the management and treatment of this kind of Agricultural Plastic Waste (APW), especially in the light of the gap currently existing in the specialised literature. In this context, this paper reports upon findings from a combined Life Cycle Assessment (LCA) of single environmental issues (i.e., energy and water consumption, and GHG emissions) applied to a Sicilian firm, representative of APW collection and recycling to obtain Low-Density Polyethylene (LDPE) granules. The results showed that electricity consumption for the whole recycling process is the most NRPE resource demanding and the most GHG emitting input item. Moreover, the washing phase of disused covering films is the highest water demanding within the recycling process. Potential improvements could be achieved by shifting from fossil energy source to renewable one. The installation of a wind power plant would lead to around 56% and 85% reduction in NRPE resource exploitation and GHG emission, respectively. Finally, despite the huge consumption of water and NRPE resources and the resulting GHG emissions, the production of recycled-LDPE granules is far more sustainable than the virgin counterpart.

Circular economy and sustainable development in the tourism sector - An overview of the truly-effective strategies and related benefits.

Circular Economy (CE) is considered a possible solution to mitigate the environmental externalities of the tourism industry, with a view to more sustainable tourism by reducing environmental, social, and economic burdens in an integrated holistic approach. Moreover, the role of CE in tourism is highlighted by the possibility of achieving all sustainable development goals (SDGs) directly and indirectly using the links that connect SDG 12 with the others. From this point of view, this literature review was aimed at discussing the key strategies of CE applied to the tourism industry, focussing on the widespread problems of single-use plastic, excess food, and water consumption. The environmental and socio-economic benefits deriving from the application of the CE principles to waste management will be shown, by contributing to meeting all the SDGs. Many strategies have been proposed to make tourism circular and sustainable, and research revealed that those are mainly based on the concepts of reduce, reuse, recycle, and recover. This article confirmed the importance of - and the need for - research on CE in the tourism sector; further, by contributing to expanding research in this content area, it can stimulate the development and application of solutions that make the industry more efficient and resilient. This study was also conceived to raise the awareness of tourism stakeholders on the importance of CE to mitigate the negative externalities of the sector.

Accounting for circular economy principles in Life Cycle Assessments of extra-virgin olive oil supply chains - Findings from a systematic literature review.

This study was conceived with the aim of exploring applications of the circular economy (CE) principles in the olive oil sector, with the lens of Life Cycle Assessment (LCA). To that end, the authors performed a systematic literature review (SLR), from a pre-determined set of keywords that were searched for in the two most comprehensive databases of peer-reviewed journals, namely Scopus and Web-of-Science. From the screening process provided by the PRISMA model, a total of fifteen papers were selected that formed the final review sample, most of which included research on production systems in the Mediterranean region. To facilitate a comparative analysis of the findings from those studies, the latter were grouped into clusters, considering their characteristics and methodological approaches. Five articles were classified as dealing with 'closed-loop' systems wherein the resources from the valorisation of by-products were reintegrated into the same production system. The remaining articles were categorised as related to 'open loop' systems since by-products were utilised in processes and systems outside olive oil production. Notably, the 'closed-loop' systems showed the best LCA outcomes. Identified hotspots within the sector included the agricultural and packaging phases. Although comparing LCA applications is challenging due to the inherent nature of the method and researcher autonomy in selecting basic characteristics, valuable best practices emerged from the analysis of the current state of the art. These practices included valorisation of olive pomace (OP) by converting it into biogas to meet the energy needs of the system processes themselves, the collection of waste cooking oil to convert it into biodiesel, and the use of organic farming techniques in olive production. OP oil extraction emerged as a widespread practice enhancing system sustainability. Moreover, increasing industrial symbiosis by promoting proximity amongst plants was documented by this SLR to be a key factor in strengthening system sustainability.

Wastewater recovery for sustainable agricultural systems in the circular economy - A systematic literature review of Life Cycle Assessments.

Water availability and quality are known to affect agricultural production and nutrition. The aim of this study was to elaborate a systematic literature review of the most sustainable ways of wastewater treatment towards achieving circular economy (CE) in agro-industry activities. From the SLR, the authors selected twenty-seven papers that they classified into the three research themes of recovery of wastewater into irrigation water, extraction of sludge for production of bio-based compounds, and recovery of nutrients for soil amendment, including recovering of feeds for aquaculture, and recovery of nutrient biosolids for soil amendment. Results underlined that the recovery of nutrients biosolids for soil amendment can generate a GWP gain up to - 37 kg CO2-eq. So, the review highlighted that wastewater recovery for multiple purposes can be truly effective for the environmental sustainability of agricultural systems, and that LCA is a valid tool to assess and improve that sustainability. Under this perspective, this SLR's findings can stimulate public administrations at national and local scales in their planning and funding activities towards implementing circular bioeconomy paths based upon wastewater recovery for a sustainable, resilient agriculture. Overall, the authors believe that their article was effective in overviewing the current wastewater recovery paths in the CE context, and in highlighting key methodological aspects and findings of the reviewed LCAs, to advance the specialised literature and knowledge, and to guide practitioners for future LCA applications in the field. Finally, through its main findings, the article effectively contributes to the whole research project which it is part of and which the authors are deeply involved in. That research is performed under the Progetto GRINS "Growing Resilient, Inclusive and Sustainable" thanks to a PNRR M4C2- Investment 1.3 - GRINS with the aim of "Building a dataset for the circular economy of the main Italian production systems".

Findings from a streamlined life cycle assessment of PET-bottles for beverage-packaging applications, in the context of circular economy.

Economic activity, especially production, is based upon the use of natural resources. This is a fact that affects the growing pressure of the need to implement a sustainable approach to the design, manufacture, and disposal of products, as waste management and disposal have a significant impact on the environment. Therefore, the EU waste management policy aims to reduce the impact of waste on the environment and health and improve the efficient use of resources in the EU. The long-term goal of this policy is to reduce the amount of waste generated and, if generation is unavoidable, to promote its use as a resource, increase recycling and ensure safe waste disposal. These and related solutions are critical, given the growing amount of plastic waste. Under this perspective, the aim of the article was to assess the relevant environmental issues in the production of PET bottles for packaging applications, which can enable a significant improvement in the life cycle environmental profile not only of the analysed material but, also, of the downstream systems in which they are used as such or processed for finished, more complex goods. Results highlighted that, due to the largest contribution (nearly 84 %) to the environmental profile of the bottles' life cycle, a substantial improvement could be achieved by replacing 50 % of the total amount of virgin PET used with recycled PET.

A combined assessment of the energy, economic and environmental performance of a photovoltaic system in the Italian context.

Policymakers are increasingly moving towards greater investments in research in the renewable energy sector, in order to reduce costs, making private investment affordable, so as to accelerate the achievement of grid parity. This evidence boosts for investigating the way the convenience of investing in a solar photovoltaic (PV) system, in Italy, is unrelated to any form of public incentive. Under this perspective, this paper is focused upon designing a residential 3 kW PV system and providing a full set of indicators for the assessment of its multi-dimension performance in an holistic, integrated approach. Particularly, energy and environmental indicators, likewise the Energy Payback Time (EPBT), Energy Return on Investment (EROI) and Environmental Impact Mitigation potential (EIMP) allowed the authors to measure some of the relevant sustainability-related issues of a residential PV system. Those were found to be equal to 1.35 years, 7.05 and 23,215 kg CO2 eq, respectively. Whereas, the authors used the Levelized Cost of Energy (0.15064 €/kWh), the Net Present Value (€ 2881), and the Payback Period (8.26 years), to evaluate the economic and financial feasibility of the PV system modelized. The variations of EPBT and EROIEL with respect to solar radiation and the efficiency of the PV system and LCOE to discount rate and initial investment cost have been investigated through a sensitivity analysis.

Water scarcity in agriculture: An overview of causes, impacts and approaches for reducing the risks.

Freshwater is a vital resource for both ecosystem health and human survival, and it is the natural resource that is the most extracted at the global level. Excessive freshwater consumption can be responsible for a scarcity in the circulation rate, which occurs when the freshwater demand exceeds its availability. Hence, water consumption needs to be optimised in all human activities, given the increasing freshwater scarcity due to climate changes and to the annual net increase in the human population of 81,000,000. Freshwater plays many important roles in daily life for example, agriculture is responsible for nearly 70% of that withdrawal volume, and it is therefore, the most water-intensive sector. This puts emphasis upon the urgent need of transitioning towards more sustainable agricultural and food-production/consumption systems. Water Footprint (WF) is increasingly playing a guiding role in that context. Indeed, it makes it possible to quantify water consumption and related environmental consequences. With the objective of contributing to enhancement of research and of supporting practitioners and decision-makers in environmentally sustainable and resilient food production/consumption, the authors of this article addressed the relevant issues connected with: a) physical and economic water scarcity in agriculture, b) practices and tools to reduce water wastage, c) WF assessment methodologies. A number of environmental, economic, and engineering solutions were proposed to mitigate water scarcity. The improvement of irrigation technologies and practices was identified as an important major way to reduce water scarcity. Additionally, solar powered 'reverse-osmosis' is being used in many parts of the world to produce irrigation water from saline water, thereby reducing the need to extract freshwater from underground aquifers. This article confirmed the importance of research on water scarcity; moreover, it can stimulate development and application of solutions that make agricultural production/consumption more efficient and resilient.

Factors Affecting the Nutritional, Health, and Technological Quality of Durum Wheat for Pasta-Making: A Systematic Literature Review.

Durum wheat is one of the most important food sources in the world, playing a key role in human nutrition, as well as in the economy of the different countries in which its production areas are concentrated. Its grain also represents a staple and highly versatile ingredient in the development of health foods. Nonetheless, the aspects determining durum wheat's health quality and their interactions are many, complex, and not entirely known. Therefore, the present systematic literature review aims at advancing the understanding of the relationships among nutritional, health, and technological properties of durum wheat grain, semolina, and pasta, by evaluating the factors that, either positively or negatively, can affect the quality of the products. Scopus, Science Direct, and Web of Science databases were systematically searched utilising sets of keywords following the PRISMA guidelines, and the relevant results of the definitive 154 eligible studies were presented and discussed. Thus, the review identified the most promising strategies to improve durum wheat quality and highlighted the importance of adopting multidisciplinary approaches for such purposes.

A systematic literature review of life cycle assessments in the durum wheat sector.

It is recognised today that the global food system does not always deliver good nutrition for all human beings, and, additionally, dramatically contributes to climate change, environmental degradation, and biodiversity loss. In particular, the cereal sector threatens biodiversity and ecosystem functions, due to environmentally harmful farming activities, that critically alter climate conditions, along with energy, land, and water resources. According to this paper's authors' opinion, this supports the rationale of conducting a systematic literature review of Life Cycle Assessments (LCAs) in the durum wheat (DW) sector, to highlight environmental hotspots and improvement potentials in the phases of cultivation and processing into finished products like pasta and bread. Methodological aspects were also discussed in this paper, to provide useful insights on how to best perform LCA in such agri-food supply chains. Given the findings from the papers reviewed, the authors could document that the cultivation phase is the primary environmental hotspot of DW-derived food products and suggested several mitigation and improvements solution including, organic farming practices, diversified cropping systems, reduction of N fertilisers and pesticides application, and irrigation optimisation strategies. Furthermore, the review highlighted that there exist two main gaps in the literature, mainly related to the scarce attention on the organic farming sector and DW landraces, and the lack of nutritional-property accounting in LCAs. Finally, although specific, the review may be of interest to researchers, LCA practitioners, farmers and producers, policy- and decision-makers, and other stakeholders, and could support the promotion of environmental sustainability in the DW sector.

Spent coffee waste as a renewable source for the production of sustainable poly(butylene succinate) biocomposites from a circular economy perspective.

Turning waste products into useable resources is a necessity for the sustainable future of our planet. Such is the case with popular beverage coffee that produces solid waste in the form of spent coffee grounds (SCG). There is an opportunity to use SCG material as a cheap, sustainable, and biodegradable polymer filler that is received as waste from espresso machines. There have been relatively many studies that prove the concept of various agricultural and forestry waste, which can be integrated into modern green materials. Building upon this concept, we have selected a promising polyester poly(butylene succinate) (PBS) as a matrix owing to its bio-based and biodegradable nature. High loadings of SCG from 20 to 60 wt% were tested for optimal composition performance. Tensile, dynamic mechanical, thermal, and structural properties of the composites were examined, while their biodegradation in composting conditions was also analyzed. SCG filler showed different performance from various cellulose fiber-based composites, and properties significantly varied depending on loading. Compared to neat PBS, biodegradation occurred twice as fast for composite materials with high SGC loadings.

Life-Cycle Assessment in the Polymeric Sector: A Comprehensive Review of Application Experiences on the Italian Scale.

In recent years, a growing media campaign has demonized the use of plastic tout court, as solely responsible for environmental problems. Behind what is now vulgarly called plastic there are actually many applications and uses without which our daily life would be greatly penalized in the most common and routine actions. Our belief, in the role of researchers who have made polymers and their derivatives their main research object, is that sustainable use of polymeric materials is not only possible but is above all necessary. For this reason, in this review which is part of the Special Issue "State-of-the-Art Polymer Science and Technology in Italy", we offer a rundown of life-cycle assessment (LCA) studies on polymers used in the most important production and commercial sectors carried out in the last few years by Italians researchers.

How sustainable are biopolymers? Findings from a life cycle assessment of polyhydroxyalkanoate production from rapeseed-oil derivatives.

The main purpose of the article was to compare different scenarios of biopolymer production and their impacts on the environment using Life Cycle Assessment. Three alternative polyhydroxyalkanoates (PHA: amorphous PHA and poly(3-hydroxybutyrate), P(3HB)) production scenarios were considered to assess its environmental impact: Scenario A - Production of mcl-PHA/P(3HB) from crude vegetable oil; Scenario B - Production of P(3HB) with biodiesel by-product; Scenario C - Production of mcl-PHA/P(3HB) from used vegetable oil. Subject to the scenario considered, it was shown that the environmental efficiency of PHA production is highly dependent on carbon sources used, and it is strongly supporting production of mcl-PHA instead of P(3HB). As LCA study shows, due to low yield of P(3HB) in comparison to mcl-PHA production in considered processes, all the P(3HB) production scenarios have higher impacts than the production of mcl-PHA. Production processes based on bacterial fermentation had its impacts related mostly to the raw materials used and to its separation phase. Additionally, using secondary materials instead of raw ones, namely used oil instead of virgin oil, gives significant improvement with regard to environmental impact. The resource efficiency is also the identified as the key factor with sensitivity analysis that indicates the possible increase of biopolymer yield as the most beneficial factor. Biobased polymers have big environmental potential but still need significant improvement with regard to their manufacturing processes in order to become more economically benign. Preferably production of these microbial polymers should be integrated into biorefinery blocks, where such waste stream arises (e.g. biodiesel production plant).

Barrier Properties of Poly(Propylene Cyclohexanedicarboxylate) Random Eco-Friendly Copolyesters.

Random copolymers of poly(propylene 1,4-cyclohexanedicarboxylate) containing different amounts of neopentyl glycol sub-unit were investigated from the gas barrier point of view at the standard temperature of analysis (23 °C) with respect to the three main gases used in food packaging field: N2, O2, and CO2. The effect of temperature was also evaluated, considering two temperatures close to the Tg sample (8 and 15 °C) and two above Tg (30 and 38 °C). Barrier performances were checked after food contact simulants and in different relative humidity (RH) environments obtained with two saturated saline solutions (Standard Atmosphere, 23 °C, 85% of RH, with saturated KCl solution; Tropical Climate, 38 °C, 90% RH, with saturated KNO3 solution). The results obtained were compared to those of untreated film, which was used as a reference. The relationships between the gas transmission rate, the diffusion coefficients, the solubility, and the copolymer composition were established. The results highlighted a correlation between barrier performance and copolymer composition and the applied treatment. In particular, copolymerization did not cause a worsening of the barrier properties, whereas the different treatments differently influenced the gas barrier behavior, depending on the chemical polymer structure. After treatment, Fourier transform infrared analysis confirmed the chemical stability of these copolymers. Films were transparent, with a light yellowish color, slightly more intense after all treatments.

Environmental Life Cycle Assessment of marine sediment decontamination by citric acid enhanced-microwave heating.

The potential ability of microwave heating (MWH) for the remediation of marine sediments affected by severe hydrocarbon (HC) contamination was investigated. Decontamination effectiveness and environmental sustainability through a comparative Life Cycle Assessment (LCA) were addressed. Main results revealed that the application of a 650-W MWH treatment resulted in a rapid (15min) HC removal. A citric acid (CA) dose of 0.1M led to enhanced-HC removals of 76.9, 96.5 and 99.7% after 5, 10 and 15min of MW irradiation, respectively. The increase in CA dose to 0.2M resulted in a shorter successful remediation time of 10min. The exponential kinetic model adopted showed a good correlation with the experimental data with R2 values in the 0.913-0.987 range. The nature of the MW treatment was shown to differently influence the HC fraction concentration after the irradiation process. Achieved HC removals in such a short remediation time are hardly possible by other clean-up techniques, making the studied treatment a potential excellent choice. Removal mechanisms, which allowed the enhanced-MWH to operate as a highly effective multi-step technique (pure thermal desorption+chemical washing), undoubtedly represent a key factor in the whole remediation process. The LCA highlighted that the MW technology is the most environmentally sustainable alternative for sediment decontamination applications, with a total damage, which was 75.74% lower than that associated with the EK (0.0503pt).

Greenhouse gas emissions of an agro-biogas energy system: Estimation under the Renewable Energy Directive.

Agro-biogas from energy crops and by-products is a renewable energy carrier that can potentially contribute to climate change mitigation. In this context, application of the methodology defined by the Renewable Energy Directive 2009/28/EC (RED) was performed in order to estimate the 100-year Global Warming Potential (GWP100) associated with an agro-biogas supply chain (SC) in Southern Italy. Doing so enabled calculation of Greenhouse Gas (GHG) emission saving in order to verify if it is at least equal to 35% compared to the fossil fuel reference system, as specified by the RED. For the assessment, an attributional Life Cycle Assessment (LCA) approach (International Organization for Standardization (ISO), 2006a,b) was integrated with the RED methodology applied following the guidelines reported in COM(2010)11 and updated by SWD(2014)259 and Report EUR 27215 EN (2015). Moreover, primary data were collected with secondary data extrapolated from the Ecoinvent database system. Results showed that the GWP100 associated with electricity production through the biogas plant investigated was equal to 111.58gCO2eqMJe(-1) and so a 40.01% GHG-emission saving was recorded compared to the RED reference. The highest contribution comes from biomass production and, in particular, from crop cultivation due to production of ammonium nitrate in the overall amount used for crop cultivation. Based upon the findings of the study, the GHG saving calculated slightly exceeds the related minimum proposed by the RED: therefore, improvements are needed anyway. In particular, the authors documented that through replacement of ammonium nitrate with urea the GHG-emission saving would increase to almost 68%, thus largely satisfying the RED limit. In addition, the study highlighted that conservation practices, such as NT, can significantly enable reduction of the GHG-emissions coming from agricultural activities. Therefore, those practices should be increasingly adopted for cultivation of energy crops, because the latter significantly contribute to biogas production yield enhancement.

Polylactic acid trays for fresh-food packaging: A Carbon Footprint assessment.

This paper discusses application of Carbon Footprint (CF) for quantification of the 100-year Global Warming Potential (GWP100) associated with the life cycle of polylactic acid (PLA) trays for packaging of fresh foods. A comparison with polystyrene (PS)-based trays was done considering two different transport system scenarios for PLA-granule supply to the tray production firm: a transoceanic freight vessel and an intercontinental freight aircraft. Doing so enabled estimation of the influence of the transportation phase on the GHG-emission rate associated with the PLA-trays' life cycle. From the assessment, the GWP100 resulted to be mainly due to PLA-granulate production and to its transportation to the tray manufacturing facility. Also, the study documented that, depending upon the transport system considered, the CF associated with the life cycle of the PLA trays can worsen so much that the latter are no longer GHG-emission saving as they are expected to be compared to the PS ones. Therefore, based upon the findings of the study, it was possible for the authors to understand the importance and the need of accounting for the transport-related issues in the design of PLA-based products, thus preserving their environmental soundness compared to traditional petroleum-based products. In this context, the study could be used as the base to reconsider the merits of PLA usage for product manufacturing, especially when high distances are implied, as in this analysed case. So, the authors believe that new research and policy frameworks should be designed and implemented for both development and promotion of more globally sustainable options.

Assessment of the influence of energy density and feedstock transport distance on the environmental performance of methane from maize silages.

In Europe, thanks to public subsidy, the production of electricity from anaerobic digestion (AD) of agricultural feedstock has considerably grown and several AD plants were built. When AD plants are concentrated in specific areas (e.g., Northern Italy), increases of feedstock' prices and transport distances can be observed. In this context, as regards low-energy density feedstock, the present research was designed to estimate the influence of the related long-distance transport on the environmental performances of the biogas-to-electricity process. For this purpose the following transport systems were considered: farm trailers and trucks. For small distances (<5 km), the whole plant silage shows the lowest impact; however, when distances increase, silages with higher energy density (even though characterised by lower methane production per hectare) become more environmentally sustainable. The transport by trucks achieves better environmental performances especially for distances greater than 25 km.

Foamy polystyrene trays for fresh-meat packaging: Life-cycle inventory data collection and environmental impact assessment.

Food packaging systems are designed to perform series of functions mainly aimed at containing and protecting foods during their shelf-lives. However, to perform those functions a package causes environmental impacts that affect food supply chains and that come from its life-cycle phases. Therefore, package design should be done based upon not only the issues of cost, food shelf-life and safety, as well as practicality, but also of environmental sustainability. For this purpose, Life Cycle Assessment (LCA) can be applied in the packaging field with the aim of highlighting environmental hotspots and improvement potentials, thus enabling more eco-friendly products. In this context, an LCA of foamy polystyrene (PS) trays used for fresh meat packaging was performed here. The study highlighted that the highest environmental impacts come from PS-granule production and electricity consumption. In this regard, the authors underscored that there are no margins for improvement in the production of the granules and in the transport of the material inputs involved as well as of the trays to users. On the contrary, changing the energy source into a renewable one (by installing, for instance, a wind power plant) would enable a 14% damage reduction. In this way, the authors documented that alternative ways can be found for global environmental improvement of the system analysed and so for enhanced environmental sustainability of food packaging systems.

Recycled-PET fibre based panels for building thermal insulation: environmental impact and improvement potential assessment for a greener production.

A screening of Life Cycle Assessment for the evaluation of the damage arising from the production of 1 kg of recycled Polyethylene Terephthalate (RPET) fibre-based panel for building heat insulation was carried out according to the ISO 14040:2006 and 14044:2006. All data used were collected on site based on observations during site visits, review of documents and interviews with technical personnel and management. These data were processed by using SimaPro 7.3.3, accessing the Ecoinvent v.2.2 database and using the Impact 2002+ method. The study showed damage to be equal to 0.000299 points mostly due to the: 1) PET thermo-bonding fibre supply from China by means of a freight-equipped intercontinental aircraft; 2) production of bottle-grade granulate PET; 3) medium voltage electricity consumption during the manufacturing of RPET fibre panel. It was also highlighted that there were environmental benefits due to recycling through mainly avoiding significant emissions and reduced resource consumption. An improvement assessment was carried out to find solutions aimed at reducing the damage coming from the most impacting phases. Furthermore, the environmental impacts due to the production of the analysed RPET fibre-based panel were compared to other materials with the same insulating function, such as polystyrene foam, rock wool and cork slab. Finally, the environmental benefits of the recycling of PET bottles for flake production were highlighted compared to other treatment scenarios such as landfill and municipal incineration.