Towards context-independent indicators for an unbiased assessment of environmental sustainability in higher education: An application to Italian universities.

Higher education institutes (HEIs) are important drivers for the development and implementation of best practices for environmental sustainability. However, reliable indicators are needed to objectively evaluate the environmental performance of HEIs and their policies. The present paper aims at identifying suitable indicators for unbiased comparisons among different HEIs and for the identification of temporal trends in terms of environmental sustainability performance. At this aim, sustainability reports made publicly available by 24 Italian HEIs over a 10-year period were considered. Normalization of sustainability variables such as the annual electrical and thermal energy consumptions, related greenhouse gas emissions, and water consumption, against context-specific factors such as the number of users of each university, latitude, illuminance, heating degree days (HDDs) and cooling degree days allowed identifying the actual possible disturbance of the same variables. HDDs were found to positively affect the thermal energy consumption and the related CO2 emissions. Based on this, a novel indicator was formulated where the actual value of thermal energy consumption and the related CO2 emissions are divided not only by the number of users but also by the HDDs of the HEIs' locations. Indeed, this is a remarkable finding that, prior to confirmation with data from world HEIs, could be implemented in world university green ranking systems for improved and less biased sustainability assessments.

Introduction of the circular economy within developing regions: A comparative analysis of advantages and opportunities for waste valorization.

The introduction of effective solid waste management strategies in developing countries should be considered for improving sustainability at global level. Many barriers should be overcome, concerning the introduction of environmental policies, effective investments, social inclusion and public awareness, which are significant issues in low-middle income countries. The Circular Economy could represent the answer for improving current solid waste management activities worldwide, since denote the principle of waste valorization and recycling for boosting developing economies. This paper is focused on this theme, analyzing main opportunities for improving the current state of solid waste management in developing big cities. The solid waste management of two countries are reviewed: Romania is the emerging country where Circular Economy is becoming a future objective due to economic aids and strength regulations which the European Union (EU) established for the nations forming parts the alliance; as a comparison, Bolivia is reported for evaluating main differences founded for developing recycling systems in a no-EU country. These two case studies could be of interest for highlighting main pros and cons of the participation into a wide organization like the EU for introducing in short terms Circular Economy principles. Moreover, a theoretical Circular Economy model for developing big cities in low-middle income countries is described within the study for effectively comparing which chances can spread for these countries as regard municipal solid waste exploitation. Despite the economic level, Romania and Bolivia are both facing with many solid waste management issues although in different magnitude. For the Romanian case study, it is visible how it cannot achieve the European goals for 2020 due the need of change in public recycling behavior. Bolivia, instead, represents the case where international aids and new investments are required, considering the informal sector into the formal management system as a real opportunity for improving local recycling rate. In conclusion, the comparison suggests how external supports led to implement the principles of the Circular Economy within a developing region. The model of Circular Economy proposed is recommended for developing big cities in order to advance a new form of safe employment, encouraging the activities that are still in action (i.e. informal sector) and boosting the principles of sustainable development.

Air pollution control through biotrickling filters: a review considering operational aspects and expected performance.

The biological removal of pollutants, especially through biotrickling filters (BTFs), has recently become attractive for the low investment and operational costs and the low secondary pollution. This paper is intended to investigate the state of the art on BTF applications. After an overview on the biodegradation process and the typical parameters involved, this paper presents the analysis of a group of 16 literature studies chosen as the references for this sector. The reference studies differ from one another by the pollutants treated (volatile organic compounds [VOC], hydrogen sulphide, nitrogen oxides and trimethylamine), the geometry and size of the BTFs, and the procedures of the tests. The reference studies are analyzed and discussed in terms of the operational conditions and the results obtained, especially with respect to the removal efficiencies (REs) and the elimination capacities (ECs) of the pollutants considered. Empty bed residence time (EBRT), pollutant loading rate, temperature, pH, oxygen availability, trickling liquid flow rate, inoculum selection and biomass control strategies revealed to be the most important operational factors influencing the removal performance of a BTF.

State of the art and advances in the impact assessment of dioxins and dioxin-like compounds.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are toxic and persistent organic pollutants that are able to enter the food chain, accumulate in the fat tissues of animals, and consequently pose a serious risk for human health. Consolidated tools for exposure assessment have been implemented during the last decades and widely used, both in the environmental monitoring and in modeling activities. Although the emissive trend and the concentrations in the environment have gradually decreased during the last 20 years, some situations are still underrated and not adequately controlled by the environmental legislation. On the other hand, a complete monitoring of all the pathways of exposure to PCDD/Fs and PCBs is technically and economically unfeasible. Therefore, this paper aims at providing an overview of the traditional approaches used to assess the impacts of PCDD/Fs and PCBs and presenting the novelties introduced during the last years. After an initial characterization of their toxicity and their effects on health, this paper focuses on activities and situations that can result in critical releases of PCDD/Fs and PCBs into the atmosphere and that can represent a hidden threat for the population. In the final part, this study presents the current methodologies for exposure assessment, summarizes the food chain models in a unified way, and puts the light on new methods that can help environmental scientists, risk assessors, and decision makers to estimate the risk related to exposure to PCDD/Fs in different contexts.

Treatment of slaughterhouse wastewaters using anaerobic filters.

In this paper, a laboratory-scale experimentation allowed comparing the performances of two upflow anaerobic packed-bed filters filled with different packing materials and operating at mesophilic conditions (30 degreeC) for treating slaughterhouse wastewaters. Methane production was experimentally evaluated considering different volumetric organic loading rates as well as feeding overloading conditions. Although filter performances declined with loading rates higher than 6 kg CODin m-3 d-1 , the chemical oxygen demand (COD) removal efficiency remained always above 60%. The experimental results allowed for determining kinetic parameters for bacterial growth rate and methane production, following Monod and Chen-Hashimoto models, respectively. Results demonstrated that the reactors reached a cellular retention time significantly greater than the hydraulic retention time. The kinetic parameter values (Ks, l/max) revealed the low microorganisms' affinity for the substrate and confirmed the moderate biodegradability of slaughterhouse wastewater. The kinetic analysis also allowed the comparison of the filters performances with another anaerobic system and the assessment of the parameters useful for real-scale plant design. The system design, applied to a medium-sized Argentinean slaughterhouse, demonstrated to (i) be energetically self-sufficient and (ii) contribute to the plant's water heating requirements.

Critical analysis of the integration of residual municipal solid waste incineration and selective collection in two Italian tourist areas.

Municipal solid waste management is not only a contemporary problem, but also an issue at world level. In detail, the tourist areas are more difficult to be managed. The dynamics of municipal solid waste production in tourist areas is affected by the addition of a significant amount of population equivalent during a few months. Consequences are seen in terms of the amount of municipal solid waste to be managed, but also on the quality of selective collection. In this article two case studies are analyzed in order to point out some strategies useful for a correct management of this problem, also taking into account the interactions with the sector of waste-to-energy. The case studies concern a tourist area in the north of Italy and another area in the south. Peak production is clearly visible during the year. Selective collection variations demonstrate that the tourists' behavior is not adequate to get the same results as with the resident population.

Microplastics removal in wastewater treatment plants: A review of the different approaches to limit their release in the environment.

In last 10 years, the interest about the presence of microplastics (MPs) in the environment has strongly grown. Wastewaters function as a carrier for MPs contamination from source to the aquatic environment, so the knowledge of the fate of this emerging contaminant in wastewater treatment plants (WWTPs) is a priority. This work aims to review the presence of MPs in the influent wastewater (WW) and the effectiveness of the treatments of conventional WWTPs. Moreover, the negative impacts of MPs on the management of the processes have been also discussed. The work also focuses on the possible approaches to tackle MPs contamination enhancing the effectiveness of the WWTPs. Based on literature results, despite WWTPs are not designed for MPs removal from WW, they can effectively remove the MPs (up to 99 % in some references). Nevertheless, they normally act as "hotspots" of MPs contamination considering the remaining concentration of MPs in WWTPs' effluents can be several orders of magnitude higher than receiving waters. Moreover, MPs removed from WW are concentrated in sewage sludge (potentially >65 % of MPs entering the WWTP) posing a concern in case of the potential reuse as a soil improver. This work aims to present a paradigm shift intending WWTPs as key barriers for environmental protection. Approaches for increasing effectiveness against MPs have been discussed in order to define the optimal point(s) of the WWTP in which these technologies should be located. The need of a future legislation about MPs in water and sludge is discussed.

Laboratory-scale anaerobic sequencing batch reactor for treatment of stillage from fruit distillation.

This work describes batch anaerobic digestion tests carried out on stillages, the residue of the distillation process on fruit, in order to contribute to the setting of design parameters for a planned plant. The experimental apparatus was characterized by three reactors, each with a useful volume of 5 L. The different phases of the work carried out were: determining the basic components of the chemical oxygen demand (COD) of the stillages; determining the specific production of biogas; and estimating the rapidly biodegradable COD contained in the stillages. In particular, the main goal of the anaerobic digestion tests on stillages was to measure the parameters of specific gas production (SGP) and gas production rate (GPR) in reactors in which stillages were being digested using ASBR (anaerobic sequencing batch reactor) technology. Runs were developed with increasing concentrations of the feed. The optimal loads for obtaining the maximum SGP and GPR values were 8-9 gCOD L(-1) and 0.9 gCOD g(-1) volatile solids.

Management of atmospheric pollutants from waste incineration processes: the case of Bozen.

This article presents the case study of a waste incinerator located in a region rich in natural and environmental resources, and close to the city of Bozen, where there are about 100,000 inhabitants. Local authorities paid special attention to the effect of the plant on human health and the surrounding environment. Indeed, among the measures adopted to control the emissions, in 2003 an automatic sampling system was installed specifically to monitor polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emissions during the complete operation time of the plant. The continuous sampling system was coupled directly to aerosol spectrometers for the determination of fine and ultra-fine particles in the emissions of the plant. The measurement results suggest that the waste incineration plant of Bozen is not a significant source of PCDD/F, or fine and ultra-fine particles. Immission measurements from other monitoring systems confirmed these results.

Overview of the Sustainable Valorization of Using Waste and By-Products in Grain Processing.

In an increasingly resource-constrained era, using waste and by-products from grain processing has a wide appeal. This is due to the nutritive value and economic aspects of this process and due to its compatibility with the trend towards more sustainable food systems. Following the fundamentals of circular economy, a current need is the effective utilization of grain waste and by-products for conversion into value-added products in the food industry. The aim of this study is twofold: (1) using bibliometrics and the literature found in various databases, we aim to understand the progress of valorizing grain waste and by-products in human nutrition. The literature within various databases, namely, Google Scholar, Web of Science, and Elsevier Scopus, has been evaluated for its merits and values. (2) We aim to explore knowledge-based strategies by reviewing the literature concerning the possible use of grain waste and by-products for the food processing industry, reducing the burden on virgin raw materials. The review allowed us to unlock the latest advances in upcycling side streams and waste from the grain processing industry.

Role of levoglucosan as a tracer of wood combustion in an alpine region.

Wood is the most used renewable energy source in the Italian Alpine regions but is one of the major sources of particulate matter too. In order to contribute to the assessment of the role of wood combustion in atmospheric pollution, some measurements of the concentration of a specific wood combustion tracer, levoglucosan, were performed and are presented and discussed in this paper, in the frame of a multi-step approach useful for decision makers. The experimental study presented in this paper was conducted in two urban sites, located in the same alpine town, during summer and winter, and in three mountain sites, where wood was expected to be widely used for domestic heating, during winter. Results showed differences between rural and urban areas and between winter and summer seasons. As explained in this paper, these analyses are useful when the role of wood combustion has to be studied and strategies for air quality improvement have to be planned and monitored.

How Should We Measure? A Review of Circular Cities Indicators.

As the world continues to urbanize, it is necessary to identify and implement new urban development models and strategies in order to meet the challenges of sustainable development. As cities continue to face challenges in becoming fully circular, the need to establish a framework to measure the circular economy in urban areas grows. Many definitions for circular cities have been developed and addressed in recent years, as have numerous indicators. To make the transition to a circular city, we must integrate the findings and develop a general definition and measurement framework. This article aims at outlining a framework for circular cities indicators based on their key characteristics, as well providing directions for fostering circularity at the city level. To accomplish this goal, we conducted a systematic review and analyzed key papers published in the field of circular economy to determine how circular cities are measured. Choosing the right indicators to use for developing, monitoring, and evaluating circular cities is a difficult task for urban policymakers, managers, and planners. This highlights the significance of standardized frameworks for urban indicators. As a result, the authors propose a framework and highlight some key points about circular cities and smart urban metabolism.

The performance evaluation of wastewater service: a protocol based on performance indicators applied to sewer systems and wastewater treatment plants.

This research aimed to identify a tool to objectively analyse the performance and the environmental contextualisation of sewer systems (SwSs) and wastewater treatment plants (WWTPs). This procedure performs assessment by calculating performance indices which could be subsequently applied to SwSs and WWTPs with different characteristics. The proposed tool can be applied conveniently over the years by managers of integrated urban water management systems for the analysis of different realities also allowing the evaluation of the effects of upgrades carried out during the management phases. The proposed analysis allows the optimisation of SwSs and can profitably guide the choice and the priority among possible interventions for the sewerage infrastructure and WWTPs providing a verification and evaluation protocol as well as a financial planning tool.

Zooming on light packaging waste differences by scanning electron microscopy.

In the present paper, different types of pure and commercial plastic waste from different EU countries (UK, France, Italy, and Romania) were investigated for microstructure surface morphology and chemical properties by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The goal of the current investigation was to determine the chemical composition of selected packaging materials and compare these measurements with data obtained through a carbon-hydrogen-nitrogen-sulfur-oxygen (CHNS-O) elemental analyzer, which is conventionally used to characterize waste materials. The capabilities of the experimental approach are discussed in connection with their application to the study of waste sample materials and in comparison with alternative experimental methods such as elemental analysis. The CHNS-O comparison is made between the present data obtained with SEM-EDXS instrument and EA 3000 elemental analyzer used in previews studies conducted by the authors. Results show a difference of composition among packaging from different countries that can affect the treatment adopted for its valorization and the strategies of circular economy.

Applications of Up-Flow Anaerobic Sludge Blanket (UASB) and Characteristics of Its Microbial Community: A Review of Bibliometric Trend and Recent Findings.

The interest in research on up-flow anaerobic sludge blanket (UASB) reactors is growing. The meta-analysis of bibliometric data highlighted the growing interest in four diverse topics: (i) energy recovery production; (ii) combination with other treatments; (iii) the study of processes for the removal of specific pollutants and, (iv) characterization of microbial community and granular sludge composition. In particular, the papers published in the first 6 months of 2021 on this process were selected and critically reviewed to highlight and discuss the results, the gaps in the literature and possible ideas for future research. Although the state of research on UASB is to be considered advanced, there are still several points that will be developed in future research such as the consolidation of the results obtained on a semi-industrial or real scale, the use of real matrices instead of synthetic ones and a more in-depth study of the effect of substances such as antibiotics on the microbiota and microbiome of UASB granular biomass. To date, few and conflicting data about the environmental footprint of UASB are available and therefore other studies on this topic are strongly suggested.

Municipal solid waste management during the SARS-COV-2 outbreak and lockdown ease: Lessons from Italy.

The literature on municipal solid waste in relation to COVID-19 is scarce. Based on the experience of Italy, the present article contributes to the strategies aimed at preventing a second virus outbreak. In fact, the mismanagement of municipal solid waste could undermine the strategies during the ease of the lockdown. During the SARS-COV-2 outbreak in Italy, there was a general decrease in the selective collection rate (-15% in one municipality with a well-developed door-to-door collection system). Delays in the publication of guidelines on waste management impacted on the safety of the operators collecting potentially infected waste. Contrarily to expectations, single-use masks and gloves do not have significant impact on waste management, accounting for <1% of the residual municipal solid waste collected annually. However, the dispersion of abandoned masks and gloves outside indoor environments is creating environmental problems. Recommendations on waste management and the protection of waste operators are discussed. Finally, guidelines on the most appropriate waste treatment are presented and analyzed. The results presented in this article show that the MSW management sector has found useful solutions to tackle COVID-19; however, these solutions are not being shared sufficiently. The case study analyzed in the present work could help define strategies for preventing or controlling similar future epidemics or pandemic episodes.

Potential environmental benefits of direct electric heating powered by waste-to-energy processes as a replacement of solid-fuel combustion in semi-rural and remote areas.

The combustion of wood-based biomass for domestic heating, which is common in rural and mountainous regions of Europe, entails significant local impacts on air quality. Worse conditions occur in low-income countries where the use of coal in household stoves is a common practice. The present paper aims at demonstrating that the combination of waste-to-energy (WtE) plants (based on direct or indirect waste combustion technologies) and direct electric heating (DEH) would be beneficial to reduce air pollution and, meanwhile, optimize the local waste management. Specifically, a WtE plant powering a DEH network will be compared with two reference scenarios of domestic heating: the use of wood/pellet stoves and coal stoves. The results show that shifting to a DEH system, powered by the nearby WtE plant, would reduce the emissions of total suspended particles, NOx, CO, VOCs, dioxins, PAHs and heavy metals by >99%, 27%, 97%, 96%, 93%, 94% and 32%, respectively, with respect to the use of solid fuel in household stoves. In addition, the higher degree of atmospheric dispersion of the off-gas from the stack of the WtE plant is expected to further reduce the impacts in terms of air quality, as estimated by an approach based on the concept of dilution factors. The avoided transportation of waste to other waste facilities outside the region would reduce the greenhouse gas emissions with respect to coal combustion and biomass burning, by 63% and 3%, respectively. The integration of local WtE and DEH could be also "mild", opening to scenarios that could improve the local air quality without renouncing totally to the habits of domestic wood combustion in mountainous regions. Mild-DEH could be designed to integrate the domestic use of wood with electrical heaters, reducing fuel use and air pollution.

Evaluation of conventional and alternative anaerobic digestion technologies for applications to small and rural communities.

The management of food waste has been considered an extremely important issue since the 1990s but finding efficient solutions for small and rural communities is still challenging. Anaerobic digestion (AD) may provide interesting opportunities in terms of carbon emissions and economic payback in the long term, but the choice of the correct technology and the spatial scale requires attention. The focus of this study is on a small rural municipality, which is selected as a case study to assess the environmental and economic sustainability of the application of two options for AD (a conventional and an alternative wet process) and two spatial scales (municipality and a consortium of municipalities). Both the AD configurations are examined in terms of biogas exploitation, through a combined heat and power generator, and in combination with a post-composting stage of the digestate. From economic and environmental perspectives, the consortium-scale application of the conventional wet process is expected to generate greater benefits in the long term, as it enables 80% more electric energy production and economic revenues/savings, and avoids carbon emissions. However, before selecting the technology, decision makers should consider the public acceptance of local communities (e.g., the susceptibility to the "not-in-my-backyard" syndrome), as the best technical-economical solution may not be the most appropriate to specific communities. The methodology developed in this paper and the discussion of the results will inform decision makers about how to identify the most appropriate alternative for their purposes.

The Sensitivity of a Specific Denitrification Rate under the Dissolved Oxygen Pressure.

The biological denitrification process is extensively discussed in scientific literature. The process requires anoxic conditions, but the influence of residual dissolved oxygen (DO) on the efficiency is not yet adequately documented. The present research aims to fill this gap by highlighting the effects of DO on the specific denitrification rate (SDNR) and consequently on the efficiency of the process. SDNR at a temperature of 20 °C (SDNR20°C) is the parameter normally used for the sizing of the denitrification reactor in biological-activated sludge processes. A sensitivity analysis of SNDR20°C to DO variations is developed. For this purpose, two of the main empirical models illustrated in the scientific literature are taken into consideration, with the addition of a deterministic third model proposed by the authors and validated by recent experimentations on several full-scale plants. In the first two models, SDNR20°C is expressed as a function of the only variable food:microrganism ratio in denitrification (F:MDEN), while in the third one, the dependence on DO is made explicit. The sensitivity analysis highlights all the significant dependence of SDNR20°C on DO characterized by a logarithmic decrease with a very pronounced gradient in correspondence with low DO concentrations. Moreover, the analysis demonstrates the relatively small influence of F:MDEN on the SDNR20°C and on the correlation between SDNR20°C and DO. The results confirm the great importance of minimizing DO and limiting, as much as possible, the transport of oxygen in the denitrification reactor through the incoming flows and mainly the mixed liquor recycle. Solutions to achieve this result in full-scale plants are reported.

Disinfection of Wastewater by UV-Based Treatment for Reuse in a Circular Economy Perspective. Where Are We at?

Among the critical issues that prevent the reuse of wastewater treatment plants (WWTPs) effluents in a circular economy perspective, the microbiological component plays a key role causing infections and diseases. To date, the use of conventional chemical oxidants (e.g., chlorine) represent the main applied process for wastewater (WW) disinfection following a series of operational advantages. However, toxicity linked to the production of highly dangerous disinfection by-products (DBPs) has been widely demonstrated. Therefore, in recent years, there is an increasing attention to implement sustainable processes, which can simultaneously guarantee the microbiological quality of the WWs treated and the protection of both humans and the environment. This review focuses on treatments based on ultraviolet radiation (UV) alone or in combination with other processes (sonophotolysis, photocatalysis and photoelectrocatalysis with both natural and artificial light) without the dosage of chemical oxidants. The strengths of these technologies and the most significant critical issues are reported. To date, the use of synthetic waters in laboratory tests despite real waters, the capital and operative costs and the limited, or absent, experience of full-scale plant management (especially for UV-based combined processes) represent the main limits to their application on a larger scale. Although further in-depth studies are required to ensure full applicability of UV-based combined processes in WWTPs for reuse of their purified effluents, excellent prospects are presented thanks to an absent environmental impact in terms of DBPs formation and excellent disinfection yields of microorganisms (in most cases higher than 3-log reduction).