Valorisation of organic waste: new developments from proton nuclear magnetic resonance characterization

The last half-century has seen a continuing population and consumption growth, increasing the competition for land, water and energy. The solution can be found in the new sustainability theories, such as the industrial symbiosis and the zero waste objective. Reducing, reusing and recycling are challenges that the whole world have to consider. This is especially important for organic waste, whose reusing gives interesting results in terms of energy release. Before reusing, organic waste needs a deeper characterization. The non-destructive and non-invasive features of both Nuclear Magnetic Resonance (NMR) relaxometry and imaging (MRI) make them optimal candidates to reach such characterization. In this research, NMR techniques demonstrated to be innovative technologies, but an important work on the hardware and software of the NMR LAGIRN laboratory was initially done, creating new experimental procedures to analyse organic waste samples. The first results came from soil-organic matter interactions. Remediated soils properties were described in function of the organic carbon content, proving the importance of limiting the addition of further organic matter to not inhibit soil processes as nutrients transport. Moreover NMR relaxation times and the signal amplitude of a compost sample, over time, showed that the organic matter degradation of compost is a complex process that involves a number of degradation kinetics, as a function of the mix of waste. Local degradation processes were studied with enhanced quantitative relaxation technique that combines NMR and MRI. The development of this research has finally led to the study of waste before it becomes waste. Since a lot of food is lost when it is still edible, new NMR experiments studied the efficiency of conservation and valorisation processes: apple dehydration, meat preservation and bio-oils production. All these results proved the readiness of NMR for quality controls on a huge kind of organic residues and waste.

New and More Sustainable Processes for the Synthesis of Phenolics: 2-phenoxyethanol and hydroxytyrosol

The research work has dealt with the study of new catalytic processes for the synthesis of fine chemicals belonging to the class of phenolics, namely 2-phenoxyethanol and hydroxytyrosol. The two synthetic procedures investigated have the advantages of being much closer to the Green Chemistry principles than those currently used industrially. In both cases, the challenge was that of finding catalysts and methods which led to the production of less waste, and used less hazardous chemicals, safer solvents, and reusable heterogeneous catalysts. In the case of 2-phenoxyethanol, the process investigated involves the use of ethylene carbonate (EC) as the reactant for phenol O-hydroxyethylation, in place of ethylene oxide. Besides being a safer reactant, the major advantage of using EC in the new synthesis is the better selectivity to the desired product achieved. Moreover, the solid catalyst based on Na-mordenite was fully recyclable. The reaction mechanism and the effect of the Si/Al ratio in the mordenite were investigated. In the case of hydroxytyrosol, which is one of the most powerful natural antioxidants, a new synthetic procedure was investigated; in fact, the method currently employed, the hydrolysis of oleuropein, an ester extracted from the waste water processing of the olive, makes use of large amounts of organic solvents (hexane, ethyl acetate), and involves several expensive steps of purification. The synthesis procedure set up involves first the reaction between catechol and 2,2-dimethoxyacetaldehyde, followed by the one-pot reduction of the intermediate to give the desired product. Both steps were optimized, in terms of catalyst used, and of reaction conditions, that allowed to reach ca 70% yield in each step. The reaction mechanism was investigated and elucidated. During a 3-month period spent at the University of Valencia (with Prof. A. Corma’s group), a process for the production of diesel additives (2,5-bis(propoxymethyl)furan) from fructose has been investigated.

Waste Heat Recovery Systems: Numerical and Experimental Analysis of organic Rankine Cycle Solutions

This thesis aims to present the ORC technology, its advantages and related problems. In particular, it provides an analysis of ORC waste heat recovery system in different and innovative scenarios, focusing on cases from the biggest to the lowest scale. Both industrial and residential ORC applications are considered. In both applications, the installation of a subcritical and recuperated ORC system is examined. Moreover, heat recovery is considered in absence of an intermediate heat transfer circuit. This solution allow to improve the recovery efficiency, but requiring safety precautions. Possible integrations of ORC systems with renewable sources are also presented and investigated to improve the non-programmable source exploitation. In particular, the offshore oil and gas sector has been selected as a promising industrial large-scale ORC application. From the design of ORC systems coupled with Gas Turbines (GTs) as topper systems, the dynamic behavior of the GT+ORC innovative combined cycles has been analyzed by developing a dynamic model of all the considered components. The dynamic behavior is caused by integration with a wind farm. The electric and thermal aspects have been examined to identify the advantages related to the waste heat recovery system installation. Moreover, an experimental test rig has been realized to test the performance of a micro-scale ORC prototype. The prototype recovers heat from a low temperature water stream, available for instance in industrial or residential waste heat. In the test bench, various sensors have been installed, an acquisitions system developed in Labview environment to completely analyze the ORC behavior. Data collected in real time and corresponding to the system dynamic behavior have been used to evaluate the system performance based on selected indexes. Moreover, various operational steady-state conditions are identified and operation maps are realized for a completely characterization of the system and to detect the optimal operating conditions.

System innovation and life cycle thinking in packaging value chain: the circularity of plastics.

Compared to other, plastic materials have registered a strong acceleration in production and consumption during the last years. Despite the existence of waste management systems, plastic_based materials are still a pervasive presence in the environment, with negative consequences on marine ecosystem and human health. The recycling is still challenging due to the growing complexity of product design, the so-called overpackaging, the insufficient and inadequate recycling infrastructure, the weak market of recycled plastics and the high cost of waste treatment and disposal. The Circular economy package, the European Strategy for plastics in a circular economy and the recent European Green Deal include very ambitious programmes to rethink the entire plastic value chain. As regards packaging, all plastic packaging will have to be 100% recyclable (or reusable) and 55% recycled by 2030. Regions are consequently called upon to set up a robust plan able to fit the European objectives. It takes on greater importance in Emilia Romagna where the Packaging valley is located. This thesis supports the definition of a strategy aimed to establish an after-use plastics economy in the region. The PhD work has set the basis and the instruments to establish the so-called Circularity Strategy with the aim to turn about 92.000t of plastic waste into profitable secondary resources. System innovation, life cycle thinking and participative backcasting method have allowed to deeply analyse the current system, orientate the problem and explore sustainable solutions through a broad stakeholder participation. A material flow analysis, accompanied by a barrier analysis, has supported the identification of the gaps between the present situation and the 2030 scenario. Eco-design for and from recycling (and a mass _based recycling rate (based on the effective amount of plastic wastes turned into secondary plastics), valorized by a value_based indicator, are the key-points of the action plan.

Catalytic liquid- and gas-phase oxidations for the synthesis of intermediates and specialty chemicals: some examples of industrial relevance

Nowadays, it is clear that the target of creating a sustainable future for the next generations requires to re-think the industrial application of chemistry. It is also evident that more sustainable chemical processes may be economically convenient, in comparison with the conventional ones, because fewer by-products means lower costs for raw materials, for separation and for disposal treatments; but also it implies an increase of productivity and, as a consequence, smaller reactors can be used. In addition, an indirect gain could derive from the better public image of the company, marketing sustainable products or processes. In this context, oxidation reactions play a major role, being the tool for the production of huge quantities of chemical intermediates and specialties. Potentially, the impact of these productions on the environment could have been much worse than it is, if a continuous efforts hadn’t been spent to improve the technologies employed. Substantial technological innovations have driven the development of new catalytic systems, the improvement of reactions and process technologies, contributing to move the chemical industry in the direction of a more sustainable and ecological approach. The roadmap for the application of these concepts includes new synthetic strategies, alternative reactants, catalysts heterogenisation and innovative reactor configurations and process design. Actually, in order to implement all these ideas into real projects, the development of more efficient reactions is one primary target. Yield, selectivity and space-time yield are the right metrics for evaluating the reaction efficiency. In the case of catalytic selective oxidation, the control of selectivity has always been the principal issue, because the formation of total oxidation products (carbon oxides) is thermodynamically more favoured than the formation of the desired, partially oxidized compound. As a matter of fact, only in few oxidation reactions a total, or close to total, conversion is achieved, and usually the selectivity is limited by the formation of by-products or co-products, that often implies unfavourable process economics; moreover, sometimes the cost of the oxidant further penalizes the process. During my PhD work, I have investigated four reactions that are emblematic of the new approaches used in the chemical industry. In the Part A of my thesis, a new process aimed at a more sustainable production of menadione (vitamin K3) is described. The “greener” approach includes the use of hydrogen peroxide in place of chromate (from a stoichiometric oxidation to a catalytic oxidation), also avoiding the production of dangerous waste. Moreover, I have studied the possibility of using an heterogeneous catalytic system, able to efficiently activate hydrogen peroxide. Indeed, the overall process would be carried out in two different steps: the first is the methylation of 1-naphthol with methanol to yield 2-methyl-1-naphthol, the second one is the oxidation of the latter compound to menadione. The catalyst for this latter step, the reaction object of my investigation, consists of Nb2O5-SiO2 prepared with the sol-gel technique. The catalytic tests were first carried out under conditions that simulate the in-situ generation of hydrogen peroxide, that means using a low concentration of the oxidant. Then, experiments were carried out using higher hydrogen peroxide concentration. The study of the reaction mechanism was fundamental to get indications about the best operative conditions, and improve the selectivity to menadione. In the Part B, I explored the direct oxidation of benzene to phenol with hydrogen peroxide. The industrial process for phenol is the oxidation of cumene with oxygen, that also co-produces acetone. This can be considered a case of how economics could drive the sustainability issue; in fact, the new process allowing to obtain directly phenol, besides avoiding the co-production of acetone (a burden for phenol, because the market requirements for the two products are quite different), might be economically convenient with respect to the conventional process, if a high selectivity to phenol were obtained. Titanium silicalite-1 (TS-1) is the catalyst chosen for this reaction. Comparing the reactivity results obtained with some TS-1 samples having different chemical-physical properties, and analyzing in detail the effect of the more important reaction parameters, we could formulate some hypothesis concerning the reaction network and mechanism. Part C of my thesis deals with the hydroxylation of phenol to hydroquinone and catechol. This reaction is already industrially applied but, for economical reason, an improvement of the selectivity to the para di-hydroxilated compound and a decrease of the selectivity to the ortho isomer would be desirable. Also in this case, the catalyst used was the TS-1. The aim of my research was to find out a method to control the selectivity ratio between the two isomers, and finally to make the industrial process more flexible, in order to adapt the process performance in function of fluctuations of the market requirements. The reaction was carried out in both a batch stirred reactor and in a re-circulating fixed-bed reactor. In the first system, the effect of various reaction parameters on catalytic behaviour was investigated: type of solvent or co-solvent, and particle size. With the second reactor type, I investigated the possibility to use a continuous system, and the catalyst shaped in extrudates (instead of powder), in order to avoid the catalyst filtration step. Finally, part D deals with the study of a new process for the valorisation of glycerol, by means of transformation into valuable chemicals. This molecule is nowadays produced in big amount, being a co-product in biodiesel synthesis; therefore, it is considered a raw material from renewable resources (a bio-platform molecule). Initially, we tested the oxidation of glycerol in the liquid-phase, with hydrogen peroxide and TS-1. However, results achieved were not satisfactory. Then we investigated the gas-phase transformation of glycerol into acrylic acid, with the intermediate formation of acrolein; the latter can be obtained by dehydration of glycerol, and then can be oxidized into acrylic acid. Actually, the oxidation step from acrolein to acrylic acid is already optimized at an industrial level; therefore, we decided to investigate in depth the first step of the process. I studied the reactivity of heterogeneous acid catalysts based on sulphated zirconia. Tests were carried out both in aerobic and anaerobic conditions, in order to investigate the effect of oxygen on the catalyst deactivation rate (one main problem usually met in glycerol dehydration). Finally, I studied the reactivity of bifunctional systems, made of Keggin-type polyoxometalates, either alone or supported over sulphated zirconia, in this way combining the acid functionality (necessary for the dehydrative step) with the redox one (necessary for the oxidative step). In conclusion, during my PhD work I investigated reactions that apply the “green chemistry” rules and strategies; in particular, I studied new greener approaches for the synthesis of chemicals (Part A and Part B), the optimisation of reaction parameters to make the oxidation process more flexible (Part C), and the use of a bioplatform molecule for the synthesis of a chemical intermediate (Part D).

The impact of swine welfare on some qualitative traits of meat and long cured animal derived products

The present dissertation collects the results of three different research trials which have the common aim to understand the effects of swine welfare (both at farm level and during transport) on the main fresh and dry-cured meat characteristics. The first trial was carried out in order to compare the effects of illumination regimes differing in light duration or light intensity on meat and ham quality of Italian heavy pigs. The results of this trial support the conclusion that, within a moderate range of light intensity and given an appropriate dark period for animal rest, an increase of light duration or intensity above the minimum mandatory levels has no negative impact on carcass composition, meat or long-cured hams quality. The second trial was designed with the aim to investigate the effects of water restriction on growth traits, animal welfare and meat and ham quality of liquid-fed heavy pigs. Overall, the parameters analyzed as concerns growth rate, behavioural traits, blood, as well as carcass, fresh meat and cured hams quality were not affected by the absence of fresh drinking water. However, since liquid feeding did not suppress drinker use or drinker manipulation in the experimental groups, water restriction does not appear to be an applicable method to obtain a reduction of water waste. The third trial, which was carried out in Canada, tested the effectiveness of water sprinkling market-weight pigs (115±10Kg BW) before and after transport in reducing the heat stress experienced under commercial transport conditions. Our results show that the water sprinkling protocol proposed may reduce heat stress during transport and improve pork quality, particularly in specific trailer compartments. This body of research supports the general conclusion that swine welfare could be improved in different scenarios through simple and cost-effective means, without negatively affecting the quality of the main animal-derived products.

Assessing Household Food Waste in Italy: A Methodology for Detecting Drivers and Quantities

It has been estimated that one third of edible food destined for human consumption is lost or wasted along the food supply chain globally. Much of the waste comes from Global North, where consumers are considered as the bigger contributors. Different studies tried to analyze and estimate the Household Food Waste (HFW), especially in UK and Northern Europe. The result is that accurate studies at national level exist only in UK, Finland and Norway while no such studies are available in Italy, except for survey- based researches. Though, there is a widespread awareness that such methods might be not able to estimate Food Waste. Results emerging from literature clearly suggest that survey estimate inferior amounts of Food Waste as a result, if compared to waste sorting and weighting analysis or to diary studies. The hypothesis that household food waste is under-estimated when gathered through questionnaires has been enquired into. First, a literature review of behavioral economics and heuristics has been proposed; then, a literature review of the sector listing the existing methodologies to gather national data on Household Food Waste has been illustrated. Finally, a pilot experiment to test a mixed methodology is proposed. While literature suggests that four specific cognitive biases might be able to affect the reliability of answers in questionnaires, results of the present experiment clearly indicate that there is a relevant difference between how much the individual thinks to waste and he/she actually does. The result is a mixed methodology based on questionnaire, diary and waste sorting, able to overcome the cons of each single method.

Waste prevention: policy instruments and business model innovation

Waste prevention (WP) is a strategy which helps societies and individuals to strive for sufficiency in resource consumption within planetary boundaries alongside sustainable and equitable well-being and to decouple the concepts of well-being and life satisfaction from materialism. Within this dissertation, some instruments to promote WP are analysed, by adopting two perspectives: firstly, the one of policymakers, at different governance levels, and secondly, the one of business in the electrical and electronic equipment (EEE) sector. At a national level, the role of WP programmes and market-based instruments (extended producer responsibility, pay-as-you-throw schemes, deposit-refund systems, environmental taxes) in boosting prevention of municipal solid waste is investigated. Then, focusing on the Emilia-Romagna Region (Italy), the performances of the waste management system are assessed over a long period, including some years before and after an institutional reform of the waste management governance regime. The impact of a centralisation (at a regional level) of both planning and economic regulation of the waste services on waste generation and WP is analysed. Finally, to support the regional decision-makers in the prioritisation of publicly funded projects for WP, a framework for the sustainability assessment, the evaluation of success, and the prioritisation of WP measures was applied to some projects implemented by Municipalities in the Region. Trying to close the research gap between engineering and business, WP strategies are discussed as drivers for business model (BM) innovation in EEE sector. Firstly, an innovative approach to a digital tracking solution for professional EEE management is analysed. New BMs which facilitate repair, reuse, remanufacturing, and recycling are created and discussed. Secondly, the impact of BMs based on servitisation and on producer ownership on the extension of equipment lifetime is analysed, by performing a review of real cases of organizations in the EEE sector applying result- and use-oriented BMs.

Waste Mineral Filler Recycling in New Pavement Solutions

Società Azionaria Prodotti Asfaltico Bituminosi Affini (S.A.P.A.B.A. s.r.l.) is an asphalt/aggregate production plant located in Bologna, Italy. The resulting dirt and mud from the washing process is stored at specific sedimentation lakes close to the plant and are referred to as waste silt. The initiative and motivation of the current research follows the 12th objective of the sustainable development goals proposed by the United Nations. As a result, the overall aim of the current study was to reduce the impact of waste mineral fillers through recycling in new paving solutions. Considering three paving types of cement-bound, geopolymer-bound and asphalt pavements the following objectives were set: 1) To investigate the possibility of recycling waste silt in cement-bound paving solution; 2) To explore the feasibility of producing geopolymer-bound paving solutions containing waste silt; 3) To study the potential of using waste silt as fillers in different asphalt pavements. The first objective was achieved by utilizing waste silt into cement-bound materials. For this purpose, the by-product was introduced to cement mortars and was partially replaced (20%) with the natural sand. Moreover, statistical models were used to produce concrete paving blocks. The second objective was pursued by studying the feasibility of using the waste silt as a filler in geopolymer cement products. Following a comprehensive review, the silt was thermally calcined and used as filler in geopolymer cement and paving blocks. The third objective was achieved by evaluating the rheological and mechanical performance of hot mix, porous and semi-flexible asphalt containing waste silt. The limestone filler of a hot mix asphalt was replaced with thermally and untreated waste silt. To sum up, different paving blocks and asphalt pavements mixtures containing waste silt were proposed that presented acceptable performance when compared to different national and European standards.

Sustainability in buildings and waste sector: metrics, challanges, and opportunities

Nowadays, the scientific community has devoted a consistent effort to the sustainable development of the waste management sector and resource efficiency in building infrastructures. Waste is the fourth largest source sector of emissions and the municipal solid waste management system is considered as the most complex system to manage, due to its diverse composition and fragmentation of producers and responsibilities. Nevertheless, given the deep complexity that characterize the waste management sector, sustainability is still a challenging task. Interestingly, open issues arise when dealing with the sustainability of the waste sector. In this thesis, some recent advances in the waste management sector have been presented. Specifically, through the analysis of four author publications this thesis attempted to fill the gap in the following open issues: (i) the waste collection and generation of waste considering the pillars of sustainability; (ii) the environmental and social analysis in designing building infrastructures; (iv) the role of the waste collection in boosting sustainable systems of waste management; (v) the ergonomics impacts of waste collection. For this purpose, four author publications in international peer – reviewed journals were selected among the wholly author's contributions (i.e., final publication stage).

Sustainability and environmental impact of the Italian ceramic tile industry

The increasing consumption rates among citizens and the uncontrolled exploitation of natural resources have made environmental pollution and management of waste the main problems facing humanity in its upcoming future. Together with generation of energy and transport, industrial production certainly plays a key role in the genesis of these problems. It is for this reason that the concepts of environmental, social and economic sustainability have emerged over the years as the cornerstones for future development. In light of this, the most forward-looking industries have begun to study their impact on environment and society in order to improve their performances and, at the same time, to anticipate the increasingly rigorous environmental regulations. In this work, various performance indicators related to the Italian ceramic tile sector will be presented and discussed. In particular, the emission factor of characteristic pollutants will be reported on a period of up to fifteen years while data regarding waste management, concentration of pollutants and emission legal limits for the last decade will be here disclosed as a result of a vast analysis on recorded data. The collected information describes the present level of performance of the ceramic tile manufacturing industries in Italy and shows how recycling is now a consolidated reality and how some pollutants, such as particulate matter, fluorine and lead are actually disappearing from production processes and how others, such as volatile organic compounds, are increasing instead. Moreover, the adoption of alternative raw materials for the production of ceramic tiles is discussed and the implementation of the recycling of various waste is addressed at experimental or industrial scale. Finally, the development of a new ceramic engobe with high content of waste glass (20%) is presented as an experimental example of reutilization of resources in the ceramic tile industry.

Understanding food waste through behavioural theories in different settings

SDG 12.3 aims to promote sustainable consumption and production patterns by addressing the global food loss and waste problem. Given the multiple interrelated impacts, food waste is recognized as one of the major food system challenges. The scope of this work is to contribute to the understanding on food waste generation and potential approaches to tackle it. This work was specifically designed to achieve the following goals: 1) Understand specific factors that affect individual behaviours to generate FW at household, 2) Analyse the effective ways to reduce FW through behaviour change perspective given the catering and hospitality sector, and 3) Provide an evidence synthesis on intervention study that incorporate stakeholder insights focus on school meals. The first goal of identifying food waste drivers was achieved by the systematically reviewing on peer-reviewed and grey literature. The Motivation-Opportunity-Ability (MOA) framework was applied to frame consumer behavioural drivers and identify levers that could be potentially utilized to reduce food waste. Consumer segmentation was further discussed to provide insights for developing tailored food waste reduction interventions. The second goal required the identification on practical interventions, which has been accomplished by systematic literature review basing on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The efficiency and working mechanism of interventions were evaluated basing on the combination of MOA and behavioural change wheel. Building on the evidence of effective interventions, a roadmap was developed for policymakers and practitioners to lead their own pathway on intervention study and upscaling. The third aim has been achieved with a school meals interventions mapping and the implementation of stakeholder workshops. The method was built on the literature review and then enriched by intervention co-design dialogue among stakeholders. The overall conclusion addressed challenges of food waste determents identification, tailored reduction interventions developing, sustainable consumption promotion with school meals.