COVID-19 and Sustainable Development Goals (SDGs): Scenario analysis through fuzzy cognitive map modeling.

The COVID-19 crisis has immensely impacted the implementation of the 2030 Agenda for Sustainable Development worldwide. This research aims at providing a policy response to support achieving the Sustainable Development Goals (SDGs) taking the COVID-19 long-term implications into account. To do so, a qualitative analytical method was employed in the following four steps. First, a fuzzy cognitive map was developed to specify causal-effect links of the interdependent SDGs in Iran as a developing country in the Middle East. Second, potential effects of the pandemic on the SDGs achievement were analyzed. Third, five strategies were formulated, including green management, sustainable food systems, energizing the labor market, inclusive education, and supporting research and technology initiatives in the energy sector. And finally, different scenarios corresponding to the five proposed strategies were tested based on the identified interconnections among the SDGs. The analysis showed that applying each of the five considered strategies or their combination would mitigate the effect of COVID-19 on the SDGs only in case of a medium pandemic activation level. Moreover, implementing a single strategy with a high activation level leads to better outcomes on the SDGs rather than applying a combination of strategies in low or medium activation levels during the pandemic situation. The provided insights support stakeholders and policy-makers involved in the post-COVID-19 recovery action plan towards implementing the 2030 Agenda for Sustainable Development.

Three pillars of sustainability in the wake of COVID-19: A systematic review and future research agenda for sustainable development.

The COVID-19 pandemic has immensely impacted the economic, social, and environmental pillars of sustainability in human lives. Due to the scholars' increasing interest in responding to the urgent call for action against the pandemic, the literature of sustainability research considering COVID-19 consequences is very fragmented. Therefore, a comprehensive review of the COVID-19 implications for sustainability practices is still lacking. This research aims to analyze the effects of COVID-19 on the triple bottom line (TBL) of sustainability to support the future sustainable development agenda. To achieve that, the following research questions are addressed by conducting a systematic literature review: (i) what is the current status of research on the TBL of sustainability considering COVID-19 implications? (ii) how does COVID-19 affect the TBL of sustainability? and (iii) what are the potential research gaps and future research avenues for sustainable development post COVID-19? The results manifest the major implications of the COVID-19 outbreak for the triple sustainability pillars and the sustainable development agenda from the economic, social, and environmental points of view. The key findings provide inclusive insights for governments, authorities, practitioners, and policy-makers to alleviate the pandemic's negative impacts on sustainable development and to realize the sustainability transition opportunities post COVID-19. Finally, five research directions for sustainable development corresponding to the United Nations' sustainable development goals (SDGs) post COVID-19 are provided, as follows: (1) sustainability action plan considering COVID-19 implications: refining sustainability goals and targets and developing measurement framework; (2) making the most of sustainability transition opportunities in the wake of COVID-19: focus on SDG 12 and SDG 9; (3) innovative solutions for economic resilience towards sustainability post COVID-19: focus on SDG 1, SDG 8, and SDG 17; (4) in-depth analysis of the COVID-19 long-term effects on social sustainability: focus on SDG 4, SDG 5, and SDG 10; and (5) expanding quantitative research to harmonize the COVID-19-related sustainability research.

Application of unsupervised learning and process simulation for energy optimization of a WWTP under various weather conditions.

This paper outlines a hybrid modeling approach to facilitate weather-based operation and energy optimization for the largest Italian wastewater treatment plant (WWTP). Two clustering methods, K-means algorithm and Gaussian mixture model (GMM) based on the expectation-maximization (EM) algorithm, were applied to an extensive dataset of historical and meteorological records. This study addresses the problem of determining the intrinsic structure of clustered data when no information other than the observed values is available. Two quantitative indexes, namely the Bayesian information criterion (BIC) and the Silhouette coefficient using Euclidean distance, as well as two general criteria, were implemented to assess the clustering quality. Furthermore, seven weather-based influent scenarios were introduced to the process simulation model, and sets of aeration strategies are proposed. The results indicate that incorporating weather-based aeration strategies in the operation of the WWTP improves plant energy efficiency.

Assessment of weather-based influent scenarios for a WWTP: Application of a pattern recognition technique.

This study proposes an integrated approach by combining a pattern recognition technique and a process simulation model, to assess the impact of various climatic conditions on influent characteristics of the largest Italian wastewater treatment plant (WWTP) at Castiglione Torinese. Eight years (viz. 2009-2016) of historical influent data namely influent flow rate (Qin), chemical oxygen demand (COD), ammonium (N-NH4) and total suspended solids (TSS), in addition to two climatic attributes, average temperature and daily mean precipitation rates (PI) from the plant catchment area, are evaluated in this study. Following the outlier removal and missing-data imputation, five influent climate-based scenarios are identified by K-means clustering approach. Statistical characteristics of clustered observations are further investigated. Finally, to demonstrate that the proposed approach could improve the process control and efficiency, a process simulation model was developed and calibrated. Steady-state simulations were conducted, and the performance of the plant was studied under five influent scenarios. Further, an optimization scenario-based method was conducted to improve the energy consumption of the plant while meeting effluent requirements. The results indicate that with the adaptation of suitable aeration strategies for each of the influent scenarios, 10-40% energy saving can be achieved while meeting effluent requirements.

Reuse of paint sludge in road pavements: Technological and environmental issues.

This paper presents some of the results obtained in a research project focused on the use of paint sludge (PS) as a modifying agent in the production of bituminous binders for paving applications. The scope of the project was to provide an innovative, sustainable and profitable solution to waste management problems which automotive industries have to face worldwide as a result of the production of PS. The authors applied for a patent which defines the industrial process for the production of PS modified binders (PSMBs). Measurements and analyses which were considered relevant for the assessment of technological feasibility included evaluation of: PS physical characteristics, PSMB high-temperature viscosity and PSMB storage stability. Environmental issues were addressed by considering PS chemical composition, gaseous emissions during PSMB production, and leaching behavior of bituminous mixtures containing PSMBs. Obtained results show that with a proper adaptation of the PSMB production process (i.e., PS drying at a higher temperature than 105°C) it is possible to comply with technological and environmental requirements such as those related to storage stability and to gaseous emissions during PSMB production and laying of bituminous mixtures. Leaching tests, aimed to evaluate runoff water quality, show no substantial difference in the release of substances in water between standard bituminous mixtures and bituminous mixtures prepared with PSMBs.

Conceptualizing environmental effects of carsharing services: A system thinking approach.

Emerging carsharing services and their interconnections with other modes of urban transport, regulations, car manufacturing and population have affected the dynamics of energy consumption, environmental pollution and greenhouse gas emission within a complex system. However, although some aspects of environmental impacts of transport sector have been investigated in the literature, well-deserved studies on the environmental effects of carsharing services following a system thinking approach is missing. This research aims at providing a comprehensive conceptual framework to systematize the interconnections between carsharing services and their environmental effects. To do this, system dynamics (SD) modeling, as a tool to simulate complex and dynamic systems, is applied and the proposed framework model is illustrated by using a causal-loop diagram (CLD). Along with analyzing the main identified causal loops within the presented CLD, relevant strategies are proposed to reduce the negative environmental effects associated with the carsharing services, considering the whole lifecycle of a shared vehicle. The proposed framework can help environment policy makers and shared mobility practitioners in long-term strategic decision-making. Moreover, it can be applied by the researchers as a basis for future research, not only for SD modeling but also other simulation and analysis structures.

Energy optimization of a wastewater treatment plant based on energy audit data: small investment with high return.

Ambitious energy targets in the 2020 European climate and energy package have encouraged many stakeholders to explore and implement measures improving the energy efficiency of water and wastewater treatment facilities. Model-based process optimization can improve the energy efficiency of wastewater treatment plants (WWTP) with modest investment and a short payback period. However, such methods are not widely practiced due to the labor-intensive workload required for monitoring and data collection processes. This study offers a multi-step simulation-based methodology to evaluate and optimize the energy consumption of the largest Italian WWTP using limited, preliminary energy audit data. An integrated modeling platform linking wastewater treatment processes, energy demand, and production sub-models is developed. The model is calibrated using a stepwise procedure based on available data. Further, a scenario-based optimization approach is proposed to obtain the non-dominated and optimized performance of the WWTP. The results confirmed that up to 5000 MWh annual energy saving in addition to improved effluent quality could be achieved in the studied case through operational changes only.

Achieving low concentrations of chromium in drinking water by nanofiltration: membrane performance and selection.

This study evaluates nanofiltration as a feasible process to reach low concentrations of chromium in drinking water and provides means for the selection of the most suitable membrane based on the specific treatment needs. Chromium removal is concerning since new stringent limits (10 µg/L) for hexavalent Cr concentration in potable water were recently adopted in various countries. Three commercial nanofiltration membranes were tested against this threshold value: two membranes made of semi-aromatic polyamide and the third having a sulfonated polyethersulfone asymmetric film as the selective layer. The rejection observed as a function of chemical composition in the feed solution suggests that electrostatic effect is an important mechanism of chromium(VI) removal for the membranes with higher surface charge and lower film density. The performance of such membranes is strongly affected by the presence of salts, especially divalent cations, which reduce both Cr(VI) rejection and the permeate flux. The removal of Cr(VI) by denser membranes is dominated by solution-diffusion and is not influenced by feed ionic strength. The exposure of membranes to high chromium concentrations and to hypochlorite, typically employed as an oxidizing agent in water treatment plants, was also investigated. An analysis of the operational membrane life is thus discussed, based on the loss in performance due to active film degradation. All three membranes showed adequate rejection of chromium from tap and well water of diverse chemical composition, suggesting that nanofiltration is an effective process to remove chromium for the production of safe drinking water. However, membranes with different properties should be adopted depending on specific feed water composition and on the productivity required from the system. A final analysis is presented to help with the choice of the most suitable nanofiltration membrane based on initial and target Cr(VI) concentration in feed and product water, respectively.

Environmental analysis of a potential district heating network powered by a large-scale cogeneration plant.

Among the solutions for the achievement of environmental sustainability in the energy sector, district heating (DH) with combined heat and power (CHP) systems is increasingly being used. The Italian city of Turin is in a leading position in this field, having one of the largest DH networks in Europe. The aim of this work is the analysis of a further development of the network, addressed to reduce the presence of pollutants in a city that has long been subject to high concentration levels. The environmental compatibility of this intervention, especially in terms of nitrogen oxides (NOx) and particulate matter (PM) emissions, is evaluated. The pollutants dispersion is estimated using the CALPUFF model. The forecasting scenario is created firstly by simulating the energy production of the main generation plants in response to the estimated heat demand, and secondly by investigating the amount and the dispersion of pollutants removed due to the elimination of the centralized residential heaters. The results show a future reduction in ground level average NOx concentration ranging between 0.2 and 4 µg/m3. The concentration of PM remains almost unchanged. Measures are then taken to lower the uncertainty in the simulation scenarios. This study provides important information on the effects of a change of the energy configuration on air quality in an urban area. The proposed methodological approach is comprehensive and repeatable.

Evaluation of mutual connections between zero-valent iron reactivity and groundwater composition in trichloroethylene degradation.

Zero-valent iron Permeable Reactive Barriers (PRBs) are an efficient and relatively low cost in situ technology for the remediation of aquifers polluted by chlorinated solvents. The groundwater composition and the zero-valent iron reactive material are linked by mutual connections. The groundwater, to a certain extent depending on its composition, is able to oxidize the metallic iron, thus decreasing its reactivity; on the other hand, the dechlorination process and the leaching of chemical species from the reactive substrate may deeply modify groundwater composition. In this study the results of some batch and leaching column tests, performed by means of Connelly iron (Environmental Technologies Inc., Canada) and different aqueous phases (distilled water and an artificial groundwater) are compared, to evaluate the influence of groundwater composition on the reactivity of the iron material for trichloroethylene (TCE) remediation. The degradation mechanisms of the pollutant are discussed. On the grounds of the gathered results the aqueous phase composition shows a strong influence on TCE degradation kinetics obtained by means of Connelly iron; in fact the presence of dissolved substances accelerates TCE degradation.

Experimental study of the pH influence on the transport mechanisms of phenols in soil.

The study of the transport mechanisms connected to solid-liquid interactions is fundamental in the determination of the extension of the pollution of a site and in the evaluation of the best remediation process to be applied. The sorption of hydrophobic ionizable organic contaminants from the groundwaters is supervised not only by the physico-chemical properties of soil and pollutants, but also by the groundwaters pH, which deeply influences their solubility in the aqueous media, and consequently their transport mechanisms in the aquifer. In this work an experimental study of the sorption of phenol and 2-nitrophenol on two soils, different in particle-size distribution, CEC and organic carbon content, was realized. The sorption potential of the soils was evaluated by means of a physical, mineralogical and chemical characterization. The experimental data coming from some batch tests, performed at pH values equal to 4, 7 and 10 were fitted by means of linear, Freundlich and Langmuir isotherms models. The soil-contaminants interaction mechanisms that influence the isotherms shapes were then analyzed and discussed, and a comparison between the theoretical and experimental values of the partitioning coefficient KD was performed.

Strategies for the enhancement of automobile shredder residues (ASRs) recycling: results and cost assessment.

With reference to the European regulation about the management of End-of-Life Vehicles (ELVs), Directive 2000/53/EC imposes the achievement of a recycling target of 85%, and 95% of total recovery by 2015. Over the last few years many efforts have been made to find solutions to properly manage the waste coming from ELVs with the aim of complying with the targets fixed by the Directive. This paper focuses on the economical evaluation of a treatment process, that includes physical (size and density), magnetic and electrical separations, performed on the light fraction of the automobile shredder residue (ASR) with the aim of reducing the amount of waste to dispose of in a landfill and enhancing the recovery of valuable fractions as stated by the EU Directive. The afore mentioned process is able to enhance the recovery of ferrous and non-ferrous metals of an amount equal to about 1% b.w. (by weight) of the ELV weight, and to separate a high energetic-content product suitable for thermal valorization for an amount close to (but not higher than) 10% b.w. of the ELV weight. The results of the economical assessment led to annual operating costs of the treatment ranging from 300,000 €/y to 350,000 €/y. Since the considered plant treats about 13,500 metrictons of ASR per year, this would correspond to an operating cost of approximately 20-25 €/t. Taking into account the amount and the selling price of the scrap iron and of the non magnetic metal recovered by the process, thus leading to a gain of about 30 €/t per ton of light ASR treated, the cost of the recovery process is balanced by the profit from the selling of the recovered metals. On the other hand, the proposed treatment is able to achieve the fulfillment of the targets stated by Directive 2000/53/EC concerning thermal valorization and reduce the amount of waste generated from ELV shredding to landfill.

Environmental-sanitary risk analysis procedure applied to artificial turf sports fields.

Owing to the extensive use of artificial turfs worldwide, over the past 10 years there has been much discussion about the possible health and environmental problems originating from styrene-butadiene recycled rubber. In this paper, the authors performed a Tier 2 environmental-sanitary risk analysis on five artificial turf sports fields located in the city of Turin (Italy) with the aid of RISC4 software. Two receptors (adult player and child player) and three routes of exposure (direct contact with crumb rubber, contact with rainwater soaking the rubber mat, inhalation of dusts and gases from the artificial turf fields) were considered in the conceptual model. For all the fields and for all the routes, the cumulative carcinogenic risk proved to be lower than 10(-6) and the cumulative non-carcinogenic risk lower than 1. The outdoor inhalation of dusts and gases was the main route of exposure for both carcinogenic and non-carcinogenic substances. The results given by the inhalation pathway were compared with those of a risk assessment carried out on citizens breathing gases and dusts from traffic emissions every day in Turin. For both classes of substances and for both receptors, the inhalation of atmospheric dusts and gases from vehicular traffic gave risk values of one order of magnitude higher than those due to playing soccer on an artificial field.

Anaerobic digestion of extruded OFMSW.

Organic fraction of municipal solid waste (OFMSW) was used to feed two pilot plants of 1000 l working in anaerobic conditions. The OFMSW had previously been treated using a system of extrusion which, due to exerted pressure, separates the undesired fractions of waste from organic waste and reduces the organic fraction in a kind of homogeneous jam. Pilot tests were performed in semi-continuous conditions with a stepwise progressive increase of the total solids content (TS) of the input material from 3% TS w/w (1.5 g VS l(-1) d(-1) organic loading rate) to 10% TS w/w (4.3 g VS l(-1) d(-1) organic loading rate) using activated sludge as diluting agent. The average specific biogas production obtained was 600 l kg(-1)VS. When the input TS content was increased to 10% w/w, the biogas average specific production went up to 800 l kg(-1)VS. The methane content in the biogas was always higher than 60% measured by volume.

Participatory approach, acceptability and transparency of waste management LCAs: case studies of Torino and Cuneo.

The paper summarises the main results obtained from two extensive applications of Life Cycle Assessment (LCA) to the integrated municipal solid waste management systems of Torino and Cuneo Districts in northern Italy. Scenarios with substantial differences in terms of amount of waste, percentage of separate collection and options for the disposal of residual waste are used to discuss the credibility and acceptability of the LCA results, which are adversely affected by the large influence of methodological assumptions and the local socio-economic constraints. The use of site-specific data on full scale waste treatment facilities and the adoption of a participatory approach for the definition of the most sensible LCA assumptions are used to assist local public administrators and stakeholders showing them that LCA can be operational to waste management at local scale.

Foundry waste recycling in moulding operations and in the ceramic industry.

An industrial treatment was performed by the Sasil plant of Brusnengo (Biella, Northern Italy), which is part of the Gruppo Minerali S.p.A. (Novara, Northern Italy), to consider the reclamation of bentonite bonded moulding sands obtained from the Teksid Italia S.p.A. cast iron foundry plant in Crescentino (Vercelli, Northern Italy). An evaluation of the fine particles produced by the wet-mechanical regeneration treatment was made with the purpose of proposing their recycling as binding agents in moulding operations in the cast iron foundry and for the production of tiles in the ceramic industry. The pre-mixed product sold by bentonite suppliers (35% coal dust and 65% bentonite, 0.15 Euro/kg) could be made from the recovered fine fraction below 0.025 mm with the addition of active clay and coal dust, thus obtaining a product that will have physico-chemical properties similar to those of calcic bentonite. The improvements due to the addition of the fine particles to the usually employed clay for tile production were also underlined from the results of several baking tests. The recovery and recycling of sands and fine particles obtained from the reclamation of bentonite moulding sands will lead to a saving of raw materials and landfill space, with economic and environmental advantages.