Environmental Impact Indicators Research Articles

Vertical Haloponics: Sustainable and Resilient Productions Using Brackish Water

While the rapidly growing global population will require a significant increase in food production in the next years, the current climate, sanitary and geopolitical crises highlight the weaknesses of the actual food production systems, excessively dependent on external inputs and involving extremely complex nested scales and non-linear processes. Thus, appears clearly the need of accelerating the transition toward agricultural solutions and food systems based on the principles of the “Green Deal”, encompassing ecological resilience, environmental sustainability, local production, and universal access to healthy foods. Aquaponics (AP) can provide short and eco-friendly food supply chains with increased resource-use efficiency, high environmental sustainability, and food resilience. The sustainability of AP systems could be further increased by exploiting water resources that are not suitable for other purposes (brackish and salt water - haloponics), applying the vertical farming technology for both aquatic and vegetable species, reducing the use of fish meal in aquafeeds, valorizing the system residues (sludge) for agronomic purposes.The VERTICHALPONICS project aims to develop an innovative food production system by implementing an interdisciplinary approach. Since aquaponics combines recirculation aquaculture and hydroponics, within a close loop, it is considered environment friendly. However, given the different technical approaches, it is necessary to evaluate the differences in impacts and specially to assess whether the vertical system is really resource-efficient and economically viable for farmers, in comparison to the business-as-usual. The environmental and economic sustainability of the system is measured by the mean of a combined LCA and the LCC analysis (EN ISO 14040-44 and ISO 15686-5:2017 standards). The system expansion will be used to evaluate the beneficial effect of reducing the overall environmental burden from by-product recovery and utilization of side wastes, specifically the sludge produced. The method applied are Recipe and IPCC 2013 Global Warming Potential 100a. Environmental impact indicators will be provided using both mid-point and end-point categories thank to the Recipe Method, while the IPCC 2013 Global Warming Potential 100a will be applied to calculate the direct global warming potential of the system. Moreover, the inclusion of the agronomic valorization of the sludge will be analyzed to understand the potential in terms of avoided impacts.

Environmental impact assessment of biohydrogen production from orange peel waste by lab-scale dark and photofermentation processes

Orange peel waste (OPW), as a relevant and recoverable residue, is composed of peel, internal tissue, pulp, and seeds. This organic residue is rich in carbohydrates useful for biofuel production processes. Biohydrogen is obtained from dark fermentation (DF) and photofermentation (PF), which are complementary in the bioprocessing chain. The objective of this work was to compare the environmental impact assessment of a sequential dark–photofermentation process (Scenario DF-PF) and the individual fermentation processes: dark fermentation (Scenario DF) and photofermentation (Scenario PF). The assessment was performed at a laboratory scale, and the functional unit (FU) was defined as the production of 1 kg H2. Scenario DF showed the lowest environmental impacts regarding global warming and fossil resource scarcity indicators, with 375.5 kg CO2-eq/FU and 108.8 kg oil-eq/FU, respectively, followed by Scenario DF-PF and Scenario PF. Scenario DF-PF presented the lowest impact regarding the water consumption indicator (7.6 m3/FU), followed by Scenario DF, which had 46.6% more impact. Additionally, Scenario DF-PF required 3.3 times less substrate than Scenario DF due to more efficient substrate conversion. The high share of fossil fuels in the Mexican electricity mix directly impacts the processes that require electric energy, such as the PF process. Therefore, eco-friendly light sources should be used to minimize effects. Valorization of OPW could follow two routes depending on whether the aim is to reduce a specific environmental impact indicator or biowaste conversion efficiency.

Life Cycle Assessment of Wheat Straw Pyrolysis with Volatile Fractions Chemical Looping Combustion

Life Cycle Assessment of Wheat Straw Pyrolysis with Volatile Fractions Chemical Looping Combustion

Environmental impacts as the key objectives for perovskite solar cells optimization

With perovskite solar cell (PSC) performance already touching the limits of single junction PV devices, the major challenges have now shifted to upscaling and stability. A plethora of materials and processes have been used for making perovskite solar cells/modules in order to tackle these challenges. However, it is important to see the impact of these decision variables not only on the cost and efficiency of the final cells but also on their environmental footprint. In this work, the analysis of these different options of technologies and materials on the final environmental footprint using a cradle-to-gate life cycle assessment (LCA) approach is carried out and uncertainty with respect to these options is discussed in detail in order to gain insights into more optimal designs of perovskite solar cells. A comparison of the possible range of environmental impact indicators for perovskite solar modules with existing mature PV technologies is also presented to highlight the future prospects of perovskite solar technology in providing more eco-friendly and sustainable energy solutions. The results indicate that on average PSCs are not considerably better than existing PV technologies and show the possibility of optimizing PSCs with respect to different LCA indicators.

The impact of cleaner energy sources, advanced technology firms, and economic expansion on ecological footprints is critical in sustainable development

The environmental degradation accompanying economic growth, despite the potential mitigating effects of technological advancements and cleaner energy sources. This study examines the critical impact of cleaner energy sources, advanced technology firms, and economic expansion on ecological footprints within the context of sustainable development, focusing on the period between 2010 and 2022. By comparing the E7 (emerging seven) and G7 (Group of Seven) economies, the research aims to delineate how these factors collectively influence environmental sustainability in both developing and developed nations. Utilizing a robust panel estimation technique, the study systematically explores the relationship between the adoption of renewable energy technologies, the growth of high-tech industries, and macroeconomic expansion, alongside their respective effects on the ecological footprint, a key indicator of environmental impact. Our statistical analysis reveals significant differences between the E7 and G7 countries. For the G7, investments in cleaner energy and technology sectors have shown a more pronounced effect in reducing ecological footprints, attributed to higher efficiency standards and greater public awareness. In contrast, the E7 countries exhibit a delayed response, owing to varying stages of economic development and technological adoption, although promising trends are emerging. Notably, the G7 demonstrates a more pronounced inclination towards financial imperialism (0.043), while the E7 is significantly influenced by green energy sources (0.258). Policy implications drawn from the findings suggest that targeted investments in green technologies and renewable energy sources, coupled with robust policies supporting economic expansion in a sustainable manner, are crucial for both groups of countries. For the E7, accelerating technology transfer and adopting stricter environmental regulations are key, while the G7 should focus on innovation and the continuous improvement of energy efficiency standards. This dual approach is essential for mitigating the environmental impacts of economic growth and steering the global economy towards a more sustainable trajectory.

Life cycle assessment of cellulose nanocrystals prepared from crop straw by sequential periodate-chlorite oxidation

Life cycle assessment (LCA) of cellulose nanocrystals (CNC) prepared by sequential periodate-chlorite oxidation (SPCO) remains limited. In this study, the environmental impacts of CNC preparation at lab (LAB) and industrial (IND) scales were assessed based on the eFootprint system and data from the Chinese Life Cycle Database (CLCD). At the LAB scale, the global warming potential (GWP) reached 3410 kg CO2 eq/kg CNC. The contributions of the U2 (pulp making), U3 (periodate oxidation), U5 (concentration), and U6 (freeze-drying) unit processes were 42.9%, 22.8%, 21.3%, and 10.6%, respectively. At the IND scale, the GWP was reduced by one order of magnitude to 141 kg CO2 eq/kg CNC, and most of the other 13 category indicators of environmental impact (acidification, eutrophication, ecotoxicity, human toxicity, etc.) also showed the same trend. The contribution of the unit process U5 exceeded 50% in the 12 environmental impact indicators. The large contribution of U5 was attributable to the extensive use of ethanol. At the industrial scale, the GWP was reduced to 22.7 kg CO2 eq/kg CNC when the periodate was recycled, and an ultrafiltration membrane system was used to concentrate CNC solutions. The environmental impact of CNC prepared by SPCO was lower than that of CNC prepared by sulfuric acid hydrolysis. This study comprehensively assessed the potential environmental impacts of CNC production on an industrial scale and provided valuable data for future industrial-scale production of CNC and for comparison with alternative products.

Assessing diet quality and associated environmental impacts: A cross-sectional analysis in a middle- to older-aged Irish population

Current dietary patterns have implications for both population and planetary health, giving dietary shifts the potential to reduce these impacts. However, higher quality diets are not inherently of lower environmental impact. This paper examines the association between diet quality, defined using the Dietary Approaches to Stop Hypertension (DASH) diet, Mediterranean (MED) diet and Healthy Eating Index 2015 (HEI-2015) , and environmental impacts among middle- to older-aged adults. The cross-sectional analysis used a random sample of 1862 males and females aged 46–73 years. Diet quality scores (DQS) were derived from a validated food frequency questionnaire (FFQ). The impact of food production was estimated using greenhouse gas emissions (GHGE) and blue water use (BWU) environmental impact indicators from secondary data sources. Relationships between food groups, DQS and environmental impacts were evaluated via correlation and regression analyses. The food group red meat & offal was found to be the largest contributor to dietary GHGE and caffeinated beverages to BWU for all DQS and across all quartiles of adherence. The cumulative contribution of discretionary foods and beverages requires attention given they are superfluous to human health. In fully adjusted regression analyses, higher diet quality was associated with lower GHGE for all DQS. Conversely, higher diet quality was positively associated with water use (DASH and MED only). Encompassing principles of the DASH and MED diets in future dietary recommendations may reduce diet-related disease in later life and dietary GHGE. However, the increase of BWU as diets become healthier is a concern. Advocating for plant-based diets must be coordinated with sustainable production and supply. National solutions to increase self-sufficiency and reduce impacts and reliance on climate vulnerable countries is warranted. The population dietary shifts required for health and planet can only be realised by multi-level structural changes to food systems through policy, and not through sole expectation of individual change.

Performance Indicators for Assessing Environmental Management Plan Implementation in Water Projects

This research aims to examine the performance indicators that are crucial for assessing the implementation of environmental management plans (EMPs) in water projects. To achieve this aim, a questionnaire survey, integrating a systematic literature review (SLR), was used to identify the initial performance indicators. Subsequently, ten interviews with environmental professionals were carried out to uncover additional indicators not identified by the SLR. Following the survey design and pilot study of the survey, the data collection resulted in 112 valid responses from environmental professionals engaged in water projects in Saudi Arabia. The data analysis encompassed reliability tests, mean ranking, normalized mean analysis, exploratory factor analysis (EFA), and partial least squares structural equation modeling (PLS-SEM). The normalized mean analysis highlighted 13 critical parameters among 39 for further investigation. The EFA disclosed three underlying constructs: environmental impact indicators, operational and safety indicators, waste management, and public safety indicators. PLS-SEM was used to validate the relationship between these indicators and the successful implementation of EMPs. The results indicate that all three underlying constructs positively influence the effective execution of such plans. This is the first study to model the relationships of the performance indicators in water projects. The study’s findings underscore the importance of developing precise performance indicators tailored to diverse construction projects that are mainly focused on water facility construction. The identified performance indicators offer significant insights for policymakers, practitioners, and researchers and provide a solid foundation for the advancement of knowledge in the field of environmental management.

Phytoremediation Performance with Ornamental Plants in Monocultures and Polycultures Conditions Using Constructed Wetlands Technology.

The assessment of constructed wetlands (CWs) has gained interest in the last 20 years for wastewater treatment in Latin American regions. However, the effects of culture systems with different ornamental species in CWs for phytoremediation are little known. In this study, some chemical parameters such as total suspended solids (TSS), chemical oxygen demand (COD), phosphate (PO4-P), and ammonium (NH4-N) were analyzed in order to prove the removal of pollutants by phytoremediation in CWs. The environmental impact index based on eutrophication reduction (EI-E) was also calculated to estimate the cause-effect relationship using CWs in different culture conditions. C. hybrids and Dieffenbachia seguine were used in monoculture and polyculture (both species mixed) mesocosm CWs. One hundred eighty days of the study showed that CWs with plants in monoculture/polyculture conditions removed significant amounts of organic matter (TSS and COD) (p > 0.05; 40-55% TSS and 80-90% COD). Nitrogen and phosphorous compounds were significantly lower in the monoculture of D. seguine (p < 0.05) than in monocultures of C. hybrids, and polyculture systems. EI-E indicator was inversely proportional to the phosphorous removed, showing a smaller environmental impact with the polyculture systems (0.006 kg PO₄3- eq removed) than monocultures, identifying the influence of polyculture systems on the potential environmental impacts compared with the phytoremediation function in monocultures (0.011-0.014 kg PO₄3- eq removed). Future research is required to determine other types of categories of environmental impact index and compare them with other wastewater treatment systems and plants. Phytoremediation with the ornamental plants studied in CWs is a good option for wastewater treatment using a plant-based cleanup technology.

Global indicators of the environmental impacts of invasive alien species and their information adequacy.

Monitoring the extent to which invasive alien species (IAS) negatively impact the environment is crucial for understanding and mitigating biological invasions. Indeed, such information is vital for achieving Target 6 of the Kunming-Montreal Global Biodiversity Framework. However, to-date indicators for tracking the environmental impacts of IAS have been either lacking or insufficient. Capitalizing on advances in data availability and impact assessment protocols, we developed environmental impact indicators to track realized and potential impacts of IAS. We also developed an information status indicator to assess the adequacy of the data underlying the impact indicators. We used data on 75 naturalized amphibians from 82 countries to demonstrate the indicators at a global scale. The information status indicator shows variation in the reliability of the data and highlights areas where absence of impact should be interpreted with caution. Impact indicators show that growth in potential impacts are dominated by predatory species, while potential impacts from bothpredation and disease transmission are distributed worldwide. Using open access data, the indicators are reproducible and adaptable across scales and taxa and can be used to assess global trends anddistributions of IAS, assisting authorities in prioritizing control efforts and identifying areas at risk of future invasions. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

Comprehensive analysis of a high temperature solar powered trigeneration system: An energy, exergy, and exergo-environmental (3E) assessment

In the present work, helium serves as the primary working fluid within the supercritical Brayton cycle, employed to generate power through a solar power tower system. The conventional Brayton cycle for recovering the wasted heat is combined with a cascaded vapor absorption-compression refrigeration system to increase the overall system’s performance. Additional benefits of this integrated system include the ability to supply enhanced heating and cooling for food storage applications at lower temperatures. A comprehensive analysis of the combined system was conducted based on exergy, energy, and exergo-environmental (3E) factors a using computational technique engineering equation solver. The combined system’s energy, exergy efficiency, and power output were determined to be 28.82%, 39.53%, and 14.865 kW, respectively. The coefficient of performances for cooling and heating were observed as 0.5391 and 1.539 respectively. Approximately 78.18% of the total exergy destruction within the entire plant can be attributed to the solar subsystem, which amounts to 22.763 kW. As direct normal irradiance rises, the environmental impact index decreases from 1.6504 to 0.6801, while the system’s environmental stability factor improves, increasing from 0.3773 to 0.5952. Moreover, the parametric assessment highlights the substantial influence of heliostat and receiver efficiencies, as well as the helium turbine’s inlet temperature, on the trigeneration system’s performance. In addition, compared to previously published research, the current proposed system outperforms supercritical CO2 cycle systems and the conventional steam Rankine cycle systems.

Predicting environmental impacts of smallholder wheat production by coupling life cycle assessment and machine learning

Wheat grain production is a vital component of the food supply produced by smallholder farms but faces significant threats from climate change. This study evaluated eight environmental impacts of wheat production using life cycle assessment based on survey data from 274 households, then built random forest models with 21 input features to contrast the environmental responses of different farming practices across three shared socioeconomic pathways (SSPs), spanning from 2024 to 2100. The results indicate significant environmental repercussions. Compared to the baseline period of 2018–2020, a similar upward trend in environmental impacts is observed, showing an average annual growth rate of 5.88 % (ranging from 0.45 to 18.56 %) under the sustainable pathway (SSP119) scenario; 5.90 % (ranging from 1.00 to 18.15 %) for the intermediate development pathway (SSP245); and 6.22 % (ranging from 1.16 to 17.74 %) under the rapid economic development pathway (SSP585). Variation in rainfall is identified as the primary driving factor of the increased environmental impacts, whereas its relationship with rising temperatures is not significant. The results suggest adopting farming practices as a vital strategy for smallholder farms to mitigate climate change impacts. Emphasizing appropriate fertilizer application and straw recycling can significantly reduce the environmental footprint of wheat production. Standardized fertilization could reduce the environmental impact index by 11.10 to 47.83 %, while straw recycling might decrease respiratory inorganics and photochemical oxidant formation potential by over 40 %. Combined, these approaches could lower the impact index by 12.31 to 63.38 %. The findings highlight the importance of adopting enhanced farming practices within smallholder farming systems in the context of climate change. Spotlights•China's smallholder wheat farming is increasingly exposed to climate threats, risking resource depletion and pollution•Increasing eco-impacts of smallholder wheat farming could be mitigated by regulated fertilizer use and straw recycling•Life cycle assessment combined with machine learning targets future environmental impacts in dynamic climate scenarios•The study offers actionable policy advice for sustainable smallholder wheat farming practices•Future work may probe machine learning's role in forecasting smallholder production behaviors and farming decision aid

Comparison of life cycle assessment between hydrogen production from silicon waste and alkaline water electrolysis

With global warming becoming increasingly severe, environmental issues are receiving international attention. Crystalline silicon is an indispensable and important raw material for photovoltaic and semiconductor fields, but the cutting of crystalline silicon materials generates a large amount of silicon wastes. This article evaluates the environmental impact of a hydrogen production process using diamond-wire sawing silicon waste (DSSW) using the life cycle assessment (LCA) methodology. For comparison, it was also analyzed the environmental impact of the alkaline water electrolysis (AEL) hydrogen production route. In the DSSW alkaline catalyzed hydrolysis (DACH) hydrogen production route, the hydrogen production stage accounts for the main contribution of nine environmental impact indexes, including GWP, PED, ADP, AP, EP, ODP, ET, HT-cancer, and HT-non cancer, exceeding 56 %. Whereas for the AEL route, the environmental impacts of the electrolytic cell manufacturing stage can be neglected, and the operating stage contributes almost all the environmental impacts, contributing more than 92 % to the twelve environmental impact indexes. Compared to the AEL route, the DACH route has higher environmental impacts, with GWP index reaching 87.78 kg CO2 -eq/kg H2, PED index reaching 1772.90 MJ/kg H2, and IWU index reaching 622.37 kg/kg H2 which are 2.85, 4.07 and 7.56 times higher than the former, respectively. Although the environmental impact of the DACH route is significant, most of its indirect impacts were caused by the use of raw materials, and the energy consumption and direct environmental impact are both low. The environmental impact of the AEL route is mainly indirect effects generated due to the use of electricity. If clean renewable energy sources (e.g., solar PV, hydropower, geothermal or biofuels), were used for the AEL route, all twelve environmental impact indexes would be significantly reduced.

Sustainability studies in orthopaedic surgery: The carbon footprint of anterior cruciate ligament reconstruction depends on graft choice.

Environmental sustainability in medicine is a growing concern. Determining the carbon footprint of medical procedures may aid in selecting a less impactful technique moving forward. The purpose of this study was to understand the environmental impact of different anterior cruciate ligament reconstruction techniques, for which there is no consensus in terms of optimal graft. A life cycle analysis of different anterior cruciate ligament reconstruction techniques was performed. These included quadrupled semitendinosus graft, bone-patellar tendon-bone graft, iliotibial band augmented with gracilis graft, doubled semitendinosus and doubled gracilis graft, and quadriceps tendon graft. All procedures were systematically paired with a lateral extra-articular procedure. The study was conducted in a specialised centre using surgeon preference cards, with the help of a dedicated organisation for calculation according to the ISO 14044 standard. The primary outcome measure was the carbon footprint of each of the five techniques. Secondary outcomes included other environmental impact indicators, including human carcinogenic toxicity and mineral resource scarcity, among others, based on the ReCiPe 2016 midpoint guideline. The analysis had three scopes, each encompassing varying numbers of processes: graft implantation, full procedure, and entire environmental impact, from medical prescription to patient discharge. Results were reported as percentage increases compared to the graft technique with the lowest environmental impact. It was demonstrated that the surgical procedure itself accounted for <40% of the life cycle, with arthroscopy being 88% of surgery's GHG emissions, and scrubbing and draping contributing 39% to the carbon footprint. The iliotibial band augmented with gracilis tendon technique had the lowest carbon footprint (0.199 Kg Co2 eq), and the least impact in most categories at all scopes of the life cycle analysis. Using this technique as a reference, in terms of graft implantation, it was determined that extensor mechanism grafts had the highest carbon footprint (300% higher than the reference). Greater scopes showed a similar trend, with percentage differences decreasing significantly, reaching 1-3% when considering the entire environmental impact for most categories. Nevertheless, among the aforementioned factors of the ReCiPe 2016 guidelines, the semitendinosus graft paried with a lateral extra-articular procedure displayed greater difference in human carcinogenic toxicity and mineral resource scarcity (6% and 10% respectively) compared to the reference. The individual processes with the highest impact were also highlighted. In the institution where the study was conducted, the studied iliotibial band graft option was found to have the lowest environmental impact. Such analyses of standardised procedures can be replicated in individual institutions in order to determine their environmental impact. Identification of procedures with comparable results and differing environmental consequences may influence the future decision-making process. Level II, prospective cohort study.

Polymer Matrix Nanocomposites for Sustainable Packaging: A Green Approach

This research examines the characteristics and ecological viability of polymer matrix nanocomposites used in sustainable packaging. Nanocomposites were produced by combining varied proportions of polymer and nanofiller material. Through mechanical testing, it was determined that nanocomposite formulation 3 had the maximum tensile strength of 55 MPa, as well as a Young’s modulus of 3.5 GPa, showing greater stiffness in comparison to the other formulations. The evaluation of barrier qualities revealed that nanocomposite formulation 2 exhibited the most minimal oxygen permeability at a rate of 8 cc/m²/day and the lowest water vapor transmission rate at 4.5 g/m²/day, showing very efficient performance in preventing the passage of gases and moisture. The environmental impact study showed that nanocomposite formulation 3 had the most efficient energy consumption during manufacture, with a rate of 1.8 kWh/kg. It also had the lowest waste creation, with just 0.08 kg/kg, and the lowest CO2 emissions, with only 0.4 kg/kg. Nanocomposite formulation 3 demonstrated substantial improvements in mechanical characteristics, barrier properties, and environmental impact indicators when compared to the reference formulations, as shown by the percentage change analysis. In summary, this study showcases the capabilities of polymer matrix nanocomposites, specifically formulation 3, as environmentally friendly packaging materials that offer improved mechanical properties, effective barrier performance, and reduced ecological footprint. These findings contribute to the development of sustainable packaging solutions across different industries.

Ecodesign Strategies for Packaging: a Simplified Approach to Evaluate Environmental Benefits

The improvement of environmental product performance is an important driver for product development. It is also related to the optimization of product packaging solutions. This paper addresses the question related to packaging eco-design strategies. A simplified approach, based on the Life Cycle Assessment methodology and Material Flow Analysis, is proposed to quickly compare alternative design solutions in terms of environmental impacts. Quantifying impacts and identifying the most significant design parameters for these products can assist industrial companies in avoiding potential impact transfer issues and finding the best solutions for their products. Multiple environmental impact categories and indicators are included to comprehensively consider impacts on the environment, resources, and human health. The proposed approach is applied to the environmental performance evaluation of several alternative design solutions for the packaging of a professional coffee machine. Alternative designs, starting from the selection of appropriate materials to the identification of solutions suitable for the reverse supply chain, will be compared and deeply analysed in environmental terms.

Energy conservation and emission reduction through utilization of latent heat of copper slag for iron and copper recovery

Copper slag, a bulk solid waste in the copper smelting sector, has significant economic and environmental value and needs to be cleaned and utilized. Extended processing durations, limited effectiveness, and substantial energy requirements characterize conventional recycling techniques. A stirring-intensified short-duration depletion method is proposed using high-temperature hot copper slag as raw material. By efficiently using the latent heat of copper slag, 90.13% of copper in copper slag can be recovered in 45 min, and the copper content in the tailing slag is reduced to 0.23 wt%. Based on the systematic characterization, a three-stage model is developed to describe the depletion process of hot copper slag under stirring-intensified conditions: the hot-state modification stage of slag, the homogenization and modification stage of the copper matte composition, and the directed settling stage of tiny copper matte droplets assisted by mechanical stirring. The utilization of economic constraints and environmental impact indicators proves the green sustainability of the method. Compared with industrial flotation, this method can save no less than 1250 MJ of energy for every metric ton of copper slag and reduce 156 kg of carbon dioxide emissions. The method uses hot copper slag as a raw material to fully utilize the latent heat of the copper slag, realizes directional enrichment and recovery of copper and iron, and reduces the generation of copper slag from the source.

Gas production and environmental impact indicators from in vitro fermentation of diets with nopal silage (Opuntia ficus-indica L.)

Objective: To evaluate the global warming potential index (GWPI) and in vitro gas production (GP) of diets of fattening lambs fed with silage of agricultural by-products of cactus and prickly pear (Opuntia ficus-indica L.)-hibiscus grain (Hibiscus sabdariffa L.)-oats straw (Avena sativa L.)&#x0D; Design/methodology/approach: The PG technique was used to obtain the GWPI of isoproteic (crude protein (CP)) and isoenergetic diets 15%CP and 2.8 Mcal ME (metabolizable energy)): conventional diet (CD; control), with corn silage (CSD), and with 10 or 20% of cactus-prickly pear-hibiscus grain-oats straw silage (CHSD10, CHSD20), offered during 60 d to 24 fattening bighorn sheep.&#x0D; Results: Although in vitro dry matter digestibility at 72 h (IVDMD72) was better in CSD, it was similar for CHSD10, CHSD20, and CSD. CHSD10 and CHSD20 had the lowest CH4 production, GWPI, and environmental impact index (EII). The low fermentable fraction (LF; GP=24-72 h) was related to IVDMD72.&#x0D; Findings/conclusions: The cactus pear-hibiscus grain silages inclusion had the same IVDMD72 that conventional diets but decreased the CH4 emissions and the GWPI.

Comparative Environmental Evaluation of Sewage Sludge Treatment and Aggregate Production Process by Life Cycle Assessment

This study evaluated the environmental impact of landfill, incineration, and lightweight aggregate production for sewage sludge management techniques and compared the utilization of sewage-produced lightweight aggregates with natural aggregates in terms of building material production. Two scenarios were established for the life cycle assessment (LCA) of the sludge and associated product that was carried out after sludge generation. Sludge incineration and landfill deposition includes emissions from the drying, transportation, incineration of sludge, and landfill, and the production of lightweight aggregates and natural aggregates includes transportation to manufacturing facilities, the manufacturing processes themselves, and transportation of the produced aggregates to construction sites. We calculated the amount of pollutant emissions for each process in each scenario and analyzed the environmental impact index considering the environmental impact of each pollutant using the Open LCA program. The parameters used for the environmental impact index analysis for sludge management are potential acidification, climate change, eutrophication potential, human toxicity, photochemical oxidation, and stratospheric ozone depletion. The environmental impact values of lightweight aggregates (LWA) are GWP 100 441 kg CO2_Eq, AP 2.73 × 10−2 kg SO2_Eq, EP 4.46 × 10−3 kg PO4−_Eq, HTP 4.15 × 10−2 kg, 1,4-DCB_Eq, POCP 1.64 × 10−3 kg CH4_Eq, and ODP 3.41 × 10−7 kg CFC-11_Eq. We found that these values were low compared to landfill and incineration as a sewage sludge disposal method and compared to natural aggregate as a construction material production method. The environmental impact index analysis during LCA of lightweight aggregates produced from the sludge verified its positive environmental impact compared to the other potential methods of sludge management.

Effects of urban catchment characteristics on combined sewer overflows

Pollution from Combined Sewer Overflows (CSOs) cause diffuse environmental problems, which are still not satisfactorily addressed by current management practices. In this study, a sensitivity analysis was conducted on several CSO environmental impact indicators, with respect to parameters that characterise climate, urban catchment and the CSO structure activation threshold. The sensitivity analysis was conducted by running 10000 simulations with the Storm Water Management Model, using a simplified modelling approach. The indicators were calculated at yearly scale to evaluate overall potential effects on water bodies. The results could be used to estimate pollution load ranges, known the values of the input parameters, and to investigate suitable strategies to reduce pollution of the receiving water bodies. The percentage of impervious surface of the catchment was found the most influent parameter on all the indicators, and its reduction can contain the discharged pollutant mass. The activation threshold, instead, resulted the second least influent parameter on all the indicators, suggesting that its regulation alone would not be a suitable strategy to reduce CSO pollution. However, along with the reduction of the imperviousness, its increase could effectively decrease the concentration of pollutant in the overflow. The results also indicate that neither adopting sustainable urban drainage practices, nor interventions on the CSO device, significantly affect the frequency of the overflows. Therefore, restricting this latter was found to be ineffective for the reduction of both the discharged pollutant mass and the concentration of pollutant in the overflow.