The research focuses on the implementation and validation of advanced direct and indirect methods of investigation for the structural and mechanical characterisation of bimrocks. In particular, a non conventional in situ shear test has been develop in order to evaluate the strength parameters of bimrocks by properly taking into account the influence of blocks. Also, a geostatistical approach has been introduced for the investigation of block morphological and spatial properties from digital images, by means of a variographic analysis of the block Indicator Variable.

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of the degree of saturation (as well as its duration). Also the fraction of the total N2O that is actually emitted to the atmosphere depends heavily on the structure and wetness of the soil. The nitrous oxide dynamic is therefore a function of the antecedent wetness condition, the nutrient content of the peat-land, the physical characteristics of the peat-land and the vertical stratification of layers at different redox and oxygen condition, which may affect the annual N budget. In addition, the combined use of soil column and chamber experiments suggest a negative correlation between soil moisture and N2O in dynamic condition and a functional dependence of N2O emissions from the oxygen concentration. We found that the time scale of water dynamic was faster than the biological scale of trace gas emissions. Finally, the relationship of nitrous oxide versus water content was reproduced by using a lumped model which include oxygen dynamic. Preliminary results suggest that by accounting for oxygen dynamic, it is possible to reproduce the functional behavior observed in the experiment and that the latter is depending on the physical and biological properties of the soil. Keywords: water dynamics, nitrous oxide emissions, nitrate ammonification,feammox, denitrification, soil heterogeneity, oxygen, redox.

In the past decades, hydrodynamic cavitation (HC) process was the subject of study by many researchers worldwide. This phenomenon was widely studied in order to understand the reason of its negative effects on hydraulic machinery such as pumps,turbines, valves, etc. Many efforts were made in order to better understand mechanisms of HC process with the main aim of preventing its generation and trying to avoid severe physical damage such as erosions, vibrations and noises. In recent years, in order to cope with a decrease in available water resources worldwide, an increasing demand of water by population in developing/developed countries and more restrictive environmental legislations on water quality, HC was increasingly used as a novel energy-efficient technique in the field of wastewaters treatment. The main purpose of this thesis is to investigate on the effectiveness of a modified swirling-jet device called Ecowirl reactor, patented by Econovation GmbH, Germany and produced and commercialized by Officine Parisi s.r.l., Italy. Experimental studies were carried out in order to evaluate the effects of different operative conditions and parameters such as reactor geometry, flow rate, flow velocity, pressure, medium pH, medium concentration and medium temperature on (i) the degradation of a toxic and carcinogenic pollutant dye (Rhodamine B, RhB) in waste dye aqueous solutions and on (ii) the improvement of activated sludge solubilisation and aerobic sludge biodegradability in the field of biological wastewater treatments. In order to better understand the fluid dynamics into Ecowirl reactor, it was modelled. The model based on previous experimental data was implemented in a Computational Fluid Dynamics software (ANSYS, 16.2).

Interactive impacts of climate change and human activities (e.g. hydropower production) have posed urgency in examining the patterns of hydrological and thermal response in riverine ecosystems, and the potential ecological implications manifested. Hydro-geomorphic conditions are the major factors in shaping water qualities in river networks, especially under the extreme climatic events. However, when the power of nature is encountered with human regulations, represented by hydropower production, it would be well worth discussing how the pictures of riverine hydro- and thermal regimes would change over the certain range of time and space. Moreover, the possible utility of hydropower regulation as mitigation of extreme climate changes is still open question to be verified. Above-mentioned questions are answered in three aspects specifically: • Governing factors and spatial distribution model for water residence time in river networks across Germany. Based on the machine learning technique of boosted regression trees (BRT), spatial distribution of water residence time is estimated for the long-term annual average hydrological conditions and extreme cases of flood and drought. • Impacts of hydropower over temporal and spatial range are investigated by analyzing the mechanisms of hydropeaking propagation. Hydrologic and geomorphic contribution framework is proposed and applied for the upper Rhone River basin in Switzerland, a typical hydropower exploited river basin in the mountainous area. • River water temperature response as an indication for ecological status is investigated for the alpine rivers across Switzerland, excellent representatives of sensitivity and vulnerability to climate change while under highly exploitation of hydropower activities. Extreme climate change case of heatwaves in 2003 and 2006 are selected and analysed especially. Results of the three research components in correspondents to listed research questions showed that river hydrological regimes have more directly/important influence on the variation of flow availability in comparison with the geomorphologic settings. Nevertheless, geomorphologic and topologic conditions (e.g. river width, slope, and roughness coefficient) that largely control the hydraulic waves diffusion processes in a hydropower-dominated river basin determine the spatial range of hydropeaking impacts. A hierarchy framework of geophysical obstructions, hydrology, and hydraulic waves diffusion process is proposed for analyzing the spatial range of hydropeaking propagation. When the effects of hydropeaking and thermopeaking that induced by hydropower production activities are dominated in the river reach, hydropower regulation offers as great potential to mitigate extreme climate events (i.e. heatwaves). By looking into specific perspective of river hydro- and thermal regimes, hydropower regulation, and climate extremes via different scales, we investigated the interactive effects between riverine ecosystem and human-climatic impacts. We expanded the approach of water residence time estimation into the field of machine learning with spatial predictions. Impacts of hydropower regulation are first elaborated with a framework of hydropeaking propagation mechanisms. Hydropower regulation has been identified to have great potential to mitigate extreme heatwaves through altering thermal regimes in rivers. Results of the study not only contribute to river hydrology and ecology studies, but also to the river management and climate change mitigation practices.

Over the past 200 years, rivers in industrialized countries have been significantly altered by human interventions such as channelization, hydropower development, and sediment mining causing observable biogeomorphological changes. In the European Alpine region, many large rivers have been impounded and channelized, yet few studies have conducted in-depth research on the temporal patterns of the causes and trajectories of these biogeomorphological responses, in comparison to rivers that can adjust their planform. Moreover, it is well-known that within channelized rivers alternating bars may appear due to an instability of the riverbed, but the development and influence of vegetation on such bars, its feedbacks on the morphodynamics of the bars and the degree to which these mutual interaction processes responds to anthropic stressors related to alterations in the flow and sediment supply regimes has received little attention. The present research aims to disentangle the mechanisms that may determine dramatically diverging biogeomorphological trajectories in regulated Alpine rivers. It further intends to identify the underlying relations of the triad that connects vegetation – sediment – flow regime and its feedbacks in regulated, channelized, rivers with vegetated bars. The methodology comprises an interdisciplinary approach which combines field and historical investigations with theoretical predictions, and integrates a variety of spatial and temporal scales and different levels of detail in characterising processes. Two case studies in the Alpine region (the Isère river in southeast France and the Noce river in northeast Italy) were selected for a quantitative, historical analysis of the bio-morphological trajectories using remotely sensed data to investigate the apparent responses to human-induced modifications of natural processes. Both rivers have been heavily impacted, with a notable increase of human stressors since the mid-20th century which can be associated with the transition of both systems from an initial, stable dynamic state characterized by bars having only sparse colonizing vegetation with a frequent turnover to a new, apparently stable state characterised by reduced morphodynamics and an increased vegetation cover in recent decades. The Isère river, which underwent a shift from unvegetated, migrating bars to vegetated, stable bars, was further explored with a hydromorphodynamic modelling approach to investigate historical changes in riparian vegetation recruitment and survival related to changes in the flow regime. The Windows of Opportunity model was successful at revealing temporal changes in recruitment conditions in response to flow regime alterations. Further results indicated a reduction in relevant high flow events that might be competent to induce large bar migration in the system. Alterations of the flow regime are assumed to have played a major role in vegetation encroachment directly by affecting vegetation recruitment through reduced flow disturbances and indirectly inducing modifications of bar morphodynamics. Field observations of root development were also made on the Noce and Isère rivers, focusing on two species Salix alba and Phalaris arundinacea, with the aim of improving understanding of the role of roots on the presence and movement of vegetated bars. When comparing results from different sites, more predictable linear relationships between root properties and depth below the ground surface were associated with stronger flow regulation. Bar morphology (surface elevation or depth of sedimentation and sediment calibre) and flow regime were found to be the main drivers of root architecture. Furthermore, roots were found to have an important role in the stabilization of the bars with the ability to stabilise fine sediments trapped by the plant’s canopy during phases of bar aggradation. To understand the current state of channelized Alpine rivers, which often show diverging biogeomorphic features, it is necessary to understand the underlying interactions between flow, sediment, and vegetation dynamics. Only through investigating the historical biomorphological evolution of rivers and the main drivers of that evolution it is possible to design measures that can be effective in rehabilitating desired ecosystem functions that have been markedly modified by those state transitions. In summary, this study has provided novel, quantitative insights about the complexity of flow – vegetation – morphology interactions occurring in channelized river systems in relation to anthropogenic stressors causing alteration in their flow and sediment supply regimes. By integrating different approaches, this study has shown how these river systems can be highly sensitive to even small changes in the anthropogenic stressors, depending on the stage in their evolutionary trajectory, which is crucial to be detected to support the development of sustainable management strategies aimed at restoring or improving target riverine functions and processes.

The present Ph.D. research has made important contributions towards the optimization of light packaging waste to energy alternative processes such as pyrolysis and gasification. Over more the development of an original integrated municipal solid waste scenario model that integrates the experimental results obtained in the thesis have a practical meaning suitable for large scale application. The experimental study of light packaging waste pyrolysis has brought some valuable information on: mass variation and balance (the results can be applied on a kinetic model development), activation energy, energy potential of solid and liquid by-products and chemical composition of solid and liquid pyrolysis products. The optimal temperature for light packaging waste pyrolysis (paper, cardboard and plastics) was established to be more than 500°C. The present Ph.D. research has made important contributions towards the optimization of light packaging waste to energy alternative processes such as pyrolysis and gasification. Over more the development of an original integrated municipal solid waste scenario model that integrates the experimental results obtained in the thesis have a practical meaning suitable for large scale application. The experimental study of light packaging waste pyrolysis has brought some valuable information on: mass variation and balance (the results can be applied on a kinetic model development), activation energy, energy potential of solid and liquid by-products and chemical composition of solid and liquid pyrolysis products. The optimal temperature for light packaging waste pyrolysis (paper, cardboard and plastics) was established to be more than 500°C. This experimental study leads to the optimisation of air gasification process parameters at industrial scale in a rotary reactor lab-pilot installation using light packaging waste mixtures. It was concluded that hhigher equivalent ration lowers the gas quality because of oxidization reactions at occurs at the being of the process. Without taking into account the CnHm hydrocarbons except CH4, in the present experiments the syngas low heating value will reach to its maximum at 5600 Nm3/kgpackaging waste at 900°C with an equivalent rate(ER) of 0.2. The solid residue is composed by char and ash and reaches to its maxim of 17 % from the initial feed input at 800°C and 0.2 ER. At 800 °C the gas flow rate and ER ranging between 0.2 -0.3 is 1.5-1.99 Nm3/kg . As it was expected, the gas yield increases with the increasing of temperature and gasifying agent. At 900 °C and 0.2-0.3 ER the gas flow rate registered varies between 1.58-2.1 Nm3/kg packaging waste. The novelty of the research in given by the development of a flexible and environmental friendly integrated municipal solid waste scenario model. The system model combines the selective collection rate, recycling processes, advanced mechanical sorting, solid recovered fuel production and proposes two waste to energy recovery facilities (combustion or gasification). The analyzed system complies with the EU principle of biodegradable materials minimization and is in agreement with the principle of adopting energy recovery after the implementation of material recycling options. In all cases studied, the analyzed integrated municipal solid waste system (IMSWS) minimizes the landfilling of materials and increases the energetic potential of the waste sent to energy recovery.

Recent epidemiological studies have reinforced the link between short and long-term exposure to air pollutants and adverse effects on public health especially over the weaker part of the population, like children and older adults. The creation of simple tools to locate sensible areas as well as of dedicated Spatial Decision Support System (SDSS) to improve the management of pollution risk areas system is strongly advised. The aim of this work is to develop a SDSS methodology, based on easy to find data and usable by decision makers, to assess and reduce the impact of air pollutants in a urban context. To achieve this goals I tested the exploitability of a set of low-cost sensors for outdoor air quality monitoring, I characterized the urban micro-environments and the spatial variability of air pollutants using remote sensing compared to field data and eventually I developed a SDSS to improve the public health designing and comparing different scenarios. The city centre of Edinburgh has been used as study case for the purposed methodology. To test the reliability and applicability of low cost sensors as proxies for remote sensed data, we conducted a measurements campaign to compare the observed data between an official measurements station (OMS) in Trento (Italy) and electrochemical and thick film sensors respectively of Carbon Monoxide (CO) and Ozone ($O_3$). Due to data quality and availability we decided to characterize the urban micro-environments of Edinburgh (Scotland, UK) in eight main classes (water, grass, vegetation, road, car, bus, buildings and shadow) combining the Geographic Object-Based Image Analysis (GEOBIA) with Machine Learning algorithms to process the high resolution (0.25m x 0.25m) RGB aerial ortho-rectified images. This land-use characterization combined with other geographical informations, like the classification of the roads and the urban morphology, were compared with 37 Nitrogen Dioxide (NO2) concentration data, collected using passive tubes during a six week campaign of measurements conducted by the school of Chemistry of the University of Edinburgh. I developed a new open-source GIS python library (PyGRASS), integrated in the stable release of GRASS GIS, to speed-up the prototyping phase and to create and test new GIS tools and methodologies. Different studies on SDSS were carried out to implement procedures and models. Based on these models and data all the factors (land-use, roads and geo-morphological features) were ranked to identify which are driving forces for urban air quality and to help decision makers to develop new policies. The sensor tested in Trento revealed an evident drift in measurement residues for CO, furthermore the measurements were also quite sensitive to external factors such as temperature and humidity. Since these sensors required frequent recalibration in order to obtain reliable results, their use was not as low-cost as expected. The characterization of urban land-use in Edinburgh with GEOBIA and machine learning provided an overall accuracy of 93.71\% with a Cohen's k of 0.916 using a train/test dataset of 9301 objects. The $NO_2$ data confirm the assumption that air concentration is strongly dependent on geographical position and it is strongly influenced by the position of the pollutant's source. Using the results of the tests and remote sensing analysis, I developed an SDSS. Starting from the current situation, I designed three scenarios to assess the effect that different policies and actions could have on improving air quality at on the local and district level. The outcomes of this work can be used to define and compare different scenarios and develop effective policies to reduce the impact of air pollutants in an urban context using simple and easy to find data. The GIS-based tool can help to identify critical areas before deploying sensors and splitting the study area in homogeneous micro-environments clusters. The model is easy to expand following different procedures.

Governments adopt strategies to follow the objective Europe 2020 and focus on the development of Renewable Energy Technologies, RET, to improve the transition of the production of energy from fossil fuels sources to renewable energy sources, RES. More than decades before, the energy transition towards renewable energies emerges as a relevant objective of the European governments. The fluctuating prices of oil and the uncertainty on the future supply of fossil fuels open new challenges for communities to actuate an energy transition towards RES. The RET can afflict deeply the landscape structure and by this point of view the energy transition is one of the most relevant drivers in the landscape change of the last three decades. In several cases energy transition may face opposition from regions and communities because of the change that RET produce in local landscapes and related economic, cultural and ecological functions. This change has been defined as a conflict between the local narrative of the right to the landscape by local communities and the global narrative that aims at a low carbon future. Exploring the relationship between Ecosystem Services (ES) and Renewable Energy (RE), the conflict among a global perspective and a local perspective has been resumed by several authors as a trade-off among provisioning and regulating ES from one side and cultural ES from the other. The overcoming of this conflict can be based on bottom-up processes that enhance the energy transition starting by local organizations of communities that want to reach a self-sufficieny in renewable energy supply. Transition management is possible if we produce innovation at local scale. An ES approach supports the transition management and the envisioning future energy landscapes by offering transparent trade-offs, exposing risks and benefits. If societies produce clean energy it may happen that RET afflict other ES. The main paradigm for the sustainability of a energy landscape is that the introduction of RET should not cause crucial trade-offs among the other ES, this is why this research wants to study this relationship, as several authors have already stressed. By the literature review it is possible to state a general gap of knowledge in integrated approaches in the evaluation of RET, considering diverse RES and ES provided by the landscape and evaluating a trade-off through a participatory process. To fulfill such gap and produce an enhancement of knowledge, this research follows the main objective of introducing a trade-off analysis into a design approach to formulate long-term visions for sustainable energy landscapes. The results we got indicate that it is possible to plan and design with the ES sustainable energy landscape.This process facilitates a sustainable energy transition of communities through a participatory landscape design that reduce the trade-off between the Renewable Energy and the ES supplies.

Fine-grained sediment represents a significant component of the total transport load in most fluvial systems around the world that are not limited to the alluvial rivers with sandy beds. A variety of natural or human actions, such as fire, logging, flow diversion, road construction, and urban or agricultural development can increase the supply of sand to a gravel- and cobble-bedded rivers. From hydrodynamics point of view, if the coarsest part of the sediments mixture composing the bed grain size composition cannot be transported, a coarser immobile layer can develop through vertical sorting of grain size fraction. This layer has influence on the grain size transport rate describes qualitatively as a competition between absolute and relative grain size effects. The absolute size effect causes the inherent mobility of sediment grains to decrease with increasing grain size. The relative size effect tends to increase the transport rate of larger grains and decrease the transport rate of smaller grains, characterizing the supply-limitation conditions for the fine fraction of the bed composition. Two-fraction approximation (i.e. sand and gravel/cobble fraction) of widely sorted sediment might capture mixed-size transport dynamics of practical significance is suggested by a number of observations, because the fines content of the bed fs may often be more variable than that of the coarse fraction (i.e. partial mobility condition), and whose passage, intrusion, or removal may be a specific environmental or engineering objective. The problem of sand transport over gravel bed has been addressed in several recent field and laboratory studies. Bed load transport rate and suspension entrainment rate are related, among other, to the sand elevation hs in the gravel framework, because the parameter hs not only controls the amount of volume of sand available to be transported by the flow, but also affects the relative sand coverage with respect to the gravel rough elements. To this regard, experimental studies showed that the function hs controls the geometrical transition from gravel framework (i.e. fs < 0.1 - 0.2) to sand matrix with interbedded gravel clasts (i.e. fs > 0.3 - 0.4), depending on the diameter ratio of sand and gravel fraction. Moreover, sand elevation hs is also a measure of the sediment supply-limitation that, in its turns, controls the sand bedform development. A limited volume of bedload sediment leads either to smaller dimensions, the sediment starved bedform or fewer isolated bedforms. Bedform types that are typically associated with partial mobility condition are: sand ribbons, barchanoid dunes, isolated dunes and sediment starved dunes, bedload sheets and low-relif bedforms. The state of knowledge suggests that there has been relatively little attention paid to understand physically which are the hydrodynamics mechanisms that control the sand transport in a gravel bed. The relevance of the present work is mainly in offering a mechanistic tool that can be used to better understand which physical phenomena control the development of sand bedforms when sand is transported over an immobile gravel bed, specifically the present research aims to: - understand physically how the local sand surface elevation hs affects the characteristic spatial scales of the bed with sand level-dependent roughness; - understand physically how the local sand surface elevation hs influences the transport phenomenon of the sand fraction when the gavel framework is at rest; - integrate the analysis of already published work often with different specific goal compared to that stated above; - determine the hydraulics conditions that controls the sand dunes formation when the sand bed elevation hs varies in the gravel framework. On the basis of the above main objectives, the present research propose a conceptual morphodynamic model accounting for the key processes of sand transport over a gravel matrix, taking into account near-bed conditions locally adapted to the evolving sand surface patterns relative to the turbulent near-bed characteristics and to the transport characteristics of fines.

High costs for aeration, greenhouse-gas emissions and excess sludge disposal have entailed a paradigm shift in the wastewater treatment. Microalgal-bacterial-based wastewater treatments have gained increasing attention because of their potential in energy demand reduction and biomass resource recovery. In particular, photosynthetic oxygenation is combined with bacterial activity to treat wastewater avoiding external artificial aeration. To optimize the technology in order to become more competitive than activated sludge, an in-depth investigation about the treatment performance and the microbiology interactions under real operational condition is needed. This work focused on the study of wastewater-borne microalgal-bacterial consortia treating real municipal wastewater. The main objectives were to: (i) Understand the removal mechanisms and the influence of operational conditions to optimize the process; (ii) Analyze the microbial community. At first, a photo-sequencing batch reactor (PSBR), called Pilot, was started up and continuously monitored for two years to analyze the evolution of the treatment performance and of the biomass composition. At the same time, other two lab-scale PSBRs were installed to evaluate if microalgal inoculation is essential to start up a consortium. Samples of these consortia were collected over a period of one year and analyzed through microscopic observations, flow cytometry and metagenomics, to investigate the microbial structure and diversity.A second part of the research focused on the optimization of the Pilot to explore its limit in view of the scale-up of the system. In addition, respirometry was adapted to test microalgal-bacterial consortia to estimate the removal kinetic parameters for future modelling. To conclude, the research project addressed many aspects and lay the foundation to apply a methodological research approach to scale-up this promising technology.