Fossil Resource Scarcity Research Articles

Identification of the Main Environmental Impact Categories Over the Life Cycle of Hot Mix Asphalt: An Application to Green Public Procurement

Increased environmental awareness has led road agencies to consider the implementation of green public procurement (GPP). Besides sustainability rating systems, environmental indicators can also be implemented in GPP to help road agencies make informed decisions about the environmental impact of the pavement works they procure. A vast literature review revealed that it is still unclear which impact categories are responsible for the majority of the total environmental impact of asphalt mixtures. The objective of this study was to identify the impact categories with the greatest contribution to the total environmental impact of hot mix asphalt so that they can be implemented in the form of environmental indicators in GPP. The scope included conventional and polymer-modified binder and three mix design alternatives: only virgin aggregate, reclaimed asphalt pavement (RAP), and RAP with rejuvenators. The cradle-to-cradle life cycle assessment (LCA) performed showed that global warming (GW), fine particulate matter formation, fossil resource scarcity, and human non-carcinogenic toxicity were responsible for at least 90% of the total impact according to the ReCiPe 2016 hierarchic assessment method. Therefore, a simplified LCA focusing on these four impact categories seems sufficient for the purpose of comparing the environmental performance of alternatives in GPP. It was also found that GW alone accounted for approximately 50% of the total impact, which seems to make GW a good surrogate for the total impact among the asphalt mixtures evaluated. Future work should investigate whether the conclusions from this study still hold up when using secondary materials, lower temperature mixing technologies, or in-situ recycling.

Between path dependencies and renewable energy potentials: A case study of the Egyptian power system

Egypt’s power system is facing major changes. Rising demand, scarcity of fossil resources and the falling capital costs of solar and wind energy technologies pose the potential to fundamentally remake the national power fleet. Against this backdrop, the paper at hand investigates potential pathways of the domestic power system with a particular focus on regional deployment and associated impacts on the transmission network. To this end, the open-source modelling framework OSeMOSYS was adapted and deployed. The analysis evaluates renewable energy potentials for 320 sites across Egypt in eight different sub-regions. The study concludes that wind and PV installations prove to be cost-competitive and capable of shouldering a large share of projected demand growth, while their regional deployment should take required grid investments into consideration. The results also indicate that a restrained expansion of renewable energy technologies targeted by the government proves to be more costly than a more aggressive deployment pathway.

Environmental Analysis of Catalytic Adipic Acid Production Strategies from Two Different Lignocellulosic Biomasses

A rigorous life cycle assessment was used to analyze two different conceptual process strategies for catalytically producing adipic acid (AA) from corn stover (CS) or kenaf (Ke). On the basis of a system-level analysis, two major environmental impact categories [fossil resource scarcity (FRS) and global warming (GW)] were estimated for both process strategies. From the viewpoint of GW and FRS, the optimal case with a real scenario of South Korea indicates that the Ke-based AA is the most promising strategy. Compared to CS-based AA in the United States of America, Ke-based AA achieved the following savings: 0.15 kg oil equiv per kg of pure AA for FRS and 0.64 kg CO2 equiv per kg of pure AA for GW. The validation of the results on environmental impact was examined by sensitivity and uncertainty analyses, and their results indicated that the primary source for displacing the excess electricity generation and biomass composition is critical.

Environmental life cycle assessment of nano-cellulose and biogas production from manure

Due to its unique properties, nano fibrillated cellulose (NFC) has been a popular topic of research in recent years. Nevertheless, literature assessing environmental impacts of NFC production is scarce, especially for using other starting materials than wood pulp. Hence, in this study, a new approach of cascaded use of manure to produce biogas and subsequently use the cellulose containing digestate for NFC production (manure scenario) is compared to the production from Kraft pulp from hardwood chips (wood chips scenario) via life cycle assessment (LCA). To produce comparable outputs (NFC and biogas) in both scenarios a typical Austrian biogas plant with maize silage and pig slurry as input material is included in the wood chips scenario. A proxy approach is used to upscale the manure scenario from laboratory to an industrial scale (except for the pulp to NFC step) to ensure comparability of both scenarios. The impact categories global warming potential (GWP), fossil resource scarcity, freshwater eutrophication, human toxicity, terrestrial acidification (TAP) and terrestrial ecotoxicity potential are analysed referring to the functional unit of 1 kg NFC. Results show that the manure scenario has at least 45% lower impacts in all assessed categories. GWP is 4.41 kg CO2 eq./kg NFC in the manure and 9.74 kg CO2 eq./kg NFC in the wood chips scenario. The transformation step from pulp to NFC is identified as environmental hotspot due to the high electricity demand in both scenarios. Results are additionally assessed only for the industrial scale part (includes biogas and pulp production). In the latter the main difference can be found in the substrate production. While it plays a subordinate role in the manure scenario (up to 8%) as manure is seen as a waste stream with no upstream environmental impacts attached, the production of maize silage is one of the hotspots in the industrial part in the wood chips scenario. This difference is especially prominent in TAP, where the substrate production is responsible for 91% of the 0.06 kg SO2 eq. impact, which is tenfold the impact of the manure scenario. This underlines the issue of using energy crops as substrate in biogas plants. It also highlights the importance of further research of using waste streams as inputs for the electricity production and subsequent use in the pulp and paper industry. This LCA demonstrates that NFC production from manure is a sustainable alternative to the production from hardwood Kraft pulp.

Sustainability Assessment of Municipal Solid Waste in Riyadh, Saudi Arabia, in the Framework of Circular Economy Transition

Life cycle assessment (LCA) tools can be used for the environmental assessment of municipal solid waste management (MSWM) systems. The present study aims to evaluate the impact of an MSWM system in Riyadh, Saudi Arabia, under three different scenarios based on the Strategy for 2045 of Riyadh. The current scenario (S0) considers that municipal solid waste (MSW) is landfilled, scenario one (S1) considers waste to energy (WtE) as the main treatment while dry recyclables and organic waste collection schemes are introduced, and scenario two (S2) considers dry recyclables and organic waste collection schemes at the maximum level while the residual portion is treated as WtE. The system boundaries include MSW treatment and disposal by recycling, incineration, composting, and landfilling methods. The scenarios were compared using SimaPro 9.1.1.1 software, and the ReCiPe 2016 Midpoint (H) V1.04/World (2010) H method was used to assess global warming, ozone formation (human health), fine particulate matter formation, terrestrial acidification, freshwater eutrophication, mineral resource scarcity, and fossil resource scarcity. S0 was found to be the scenario with the least impact if considering just the waste treatment. However, S1 and S2 allow material and energy recovery that avoids the impact of obtaining primary resources. S1 and S2 reduced greenhouse gases (GHG) emissions by 55% and 58%, respectively, compared to S0. According to the SV2030, 2% of the electricity generated by the Kingdom would have to come from WtE, but based on the calculations, the maximum electricity from waste would be obtained with S1 fully implemented and would contribute a maximum of 1.51% to Saudi Arabia’s electricity demand. This study contributes by providing useful insights that could help decision-makers to understand the potential environmental impacts by assessing each step considered by the Strategy for 2045 for Riyadh along with the consequences on material and energy supply by using the material and energy potential of MSW.

Utilization of Banana Stem Waste Extracts Assisted by Electrode of Cu/Mg as an Environmentally Friendly Electricity Producer

The high consumption of electricity from year to year and the depletion of the availability of fossil energy have triggered an increase in energy prices and scarcity of fossil resources. This problem gives a strong impetus to seek alternative energy sources that are environmentally friendly. One of the recent technologies is the Microbial Fuel Cell (MFC) on banana stem, which can convert chemical energy into electrical energy. The purpose of this study was to determine the potential of banana stem waste extract assisted by Cu/Mg electrodes as a source of electricity as well as how the manufacturing and testing methods, and the effect of variations in the volume of banana stem extracts on the performance of electrical energy. The used steps were electrode preparation and banana stem waste preparation, then incubating the banana stem waste for 7 days, assembling the construction for research on the potential of the banana stem waste as a power producer, and research with variations in the volume of the extract and testing its strength, electric current, electric voltage, and power density. Based on the research, it was found that the greater the volume of the extract of banana stem, the greater the power density, electric voltage, and also the strong electric current produced. The volume variation of 130 mL produced a voltage of 500 mVolt, a strong current of 0.86 mA, and a power density of 84 (mW/cm 2 ). DOI: http://dx.doi.org/10.17807/orbital.v14i1.1677

The dilemma in energy transition in Malaysia: A comparative life cycle assessment of large scale solar and biodiesel production from palm oil

Energy transition to renewable energy is a current global trend. Being the world's second-largest palm oil and third-largest solar photovoltaic cells producer, Malaysia prioritizes palm biodiesel as biofuel and large scale solar as renewable energy sources. Nevertheless, disputed issues such as land occupation and embodied environmental impacts of both technologies are not backed with data-driven evaluation from a life cycle perspective. This study compares the environmental impacts and identifies the environmental hotspots of palm biodiesel and large scale solar systems using life cycle assessment methodology under the same system boundary and functional unit (i.e., 1 MJ of energy). There are 18 impact categories and three damage assessments evaluated with ReCiPe 2016 via SimaPro 9.1. The large scale solar systems perform more favorably than palm biodiesel systems by 77% in all damage assessments. The environmental hotspots in palm biodiesel (i.e., fresh fruit bunch production and milling) and large scale solar systems (i.e., electrical installation) show environmental burdens up to 15–51% in human non-carcinogenic toxicity, human carcinogenic toxicity, global warming, marine ecotoxicity, water consumption, and fossil resource scarcity. Anthropogenic carbon dioxide emissions from fossil fuel usage and land transformation in palm biodiesel systems are of positive value when compared (i.e., 11 g CO2/MJ PB) to large scale solar systems. The aluminum recycling in large scale solar systems and anaerobic digestion biogas plant in the palm biodiesel system can reduce the environmental impact between 4.13% and 25%. Policy implications are recommended for policymakers for better decision-making aligned with the national renewable energy implementation road map.

Environmental impacts of the production of synthetic natural gas from industrial carbon dioxide

Power-to-Gas technologies (PtG) are regarded as promising options to defossilize the energy system by converting and storing renewable electricity to gases. When combined with carbon capture and utilization from large point sources, such as energy intensive and hard-to-abate sectors, where a major part of CO 2 emissions cannot be avoided, PtG technologies can also play a role to mitigate CO 2 emissions. However, these technologies have several environmental impacts throughout their lifetimes that must be assessed, due to the use of resources, materials, and energy, as well as the formation of chemical by-products. Using a Life Cycle Assessment (LCA) methodology, this paper aims to assess the most significant environmental impacts of an integrated PtG system including the conversion of renewable energy to hydrogen through water wind-based electrolysis, that is further converted to synthetic natural gas (SNG) by reacting with captured CO 2 from a cement plant flue gas. More precisely, the present work innovates on both the technical and methodological perspectives. An advanced CO 2 capture process is implemented, using mixed amines solvent and innovative configuration to reduce the energy consumption to 2.3 GJ per tCO 2 captured, and include an optimized heat integration with the CO 2 conversion step. A hybrid approach combining physical and economic input data is also considered for the life cycle inventory. Additionally, both subdivision and system expansion via substitution approaches are applied to consider the multi-functionality of the systems. Simulation results show that the PtG process with CO 2 captured from cement plants flue gas reduces the overall GHG emissions by 76%. Similarly, the fossil resource scarcity is drastically reduced by over 80% thanks to the heat integration between the CO 2 capture and the CO 2 conversion processes, but also thanks to the substitution of natural gas by the CO 2 -based SNG. Nevertheless, environmental impacts of PtG are higher than conventional natural gas production for other impact categories, including freshwater eutrophication, terrestrial acidification, and mineral resource scarcity. Both data uncertainties, assessing the knowledge base underlying the input data parameters, and sensitivity analysis, assessing the value range of the parameters respectively to the environmental indicators, are conducted to test the results and highlight the uncertainty hotspots.

Comparative study of the environmental impacts of used cooking oil valorization options in Thailand

Used cooking oil (UCO) is a valuable resource that can be utilized in different ways. Appropriate management of UCO waste can provide environmental and economic benefits, compared to improper disposal practices. This study assessed the environmental impacts of potential UCO valorization options in Thailand. Altogether, 14 scenarios, including 10 for alternative energy recovering processes (S1-10) and other options such as soap production (S11), use in dry pig feed (DPF) production (S12), synthesis of plastics (S13) and polyol (S14), were considered. The defined system boundaries for each scenario include pretreatment, material and energy consumption, and waste treatment stages for the treatment of 1000 kg UCO. Environmental impacts in terms of global warming potential (GWP), freshwater eutrophication potential (FEP), fossil resource scarcity (FRS), and freshwater, terrestrial, and marine eco-toxicity (FE, TE, and ME, respectively) were analyzed using the ReCiPe Midpoint (H) method. The results revealed that all the current waste valorization options create an environmental burden and contribute towards GWP. Scenarios 7 and 10 showed environmental credits for FEP, FE, and ME indicators while scenario 9 did so for FRS. The processes direct energy consumption resulted in the highest contribution to GWP in Scenarios 1, 5–8, 10, 12, and 13. Environmental effects of material consumption and waste treatments were found to be the highest in bio-oil and DPF production, respectively. However, co-products produced could not offset the burden created by energy and material consumption. Overall, the results showed better environmental performance from energy recovery-based UCO management options compared to alternative processes.

Chemical Recycling of Plastic Waste: Comparative Evaluation of Environmental and Economic Performances of Gasification- and Incineration-based Treatment for Lightweight Packaging Waste

Chemical recycling (CR) – in enabling the use of plastic waste back as secondary carbon feedstock for production – could play a complementary role to mechanical recycling in supporting the transformation from a linear to a circular carbon economy. To date, research has predominantly focused on assessing technological aspects associated with CR of pure plastic waste streams. Little is known about its potential for treating low-quality and mixed plastic waste fractions which are unsuitable for conventional recycling and are currently incinerated. To address this gap, this investigation utilizes an integrated approach comprising of life cycle assessment and techno-economic analysis to evaluate the environmental and economic performance of CR of lightweight packaging waste via waste gasification compared to direct and indirect incineration in Germany. Results show that CR can contribute significantly – irrespective of the energy mix – to reducing climate change, terrestrial acidification, and fossil resource scarcity. In terms of economic performance, findings suggest that while CR requires higher capital investment, a multi-pronged approach which encompasses upscaling, waiver of carbon dioxide certificate costs, and price premium for CR products could increase profitability of CR to incineration. This study provides empirical support for the potential contribution of CR to complement existing strategies to combat the plastic waste challenge, and insights into market conditions which could promote its economic attractiveness. Additionally, it provides comprehensive inventory data for conventional and alternative waste treatment plants for lightweight packaging waste to inform future research on systemic assessment of CR technologies and their contributions to a circular economy.

Comparative evaluation of different operation scenarios for a full-scale wastewater treatment plant: Modeling coupled with life cycle assessment

All inputs and outputs of a technical system can be interpreted from an environmental point of view and some modifications, that are less harmful to the environment, can be incorporated into the system by using the life cycle assessment (LCA) approach. The energy footprint of wastewater treatment plants (WWTPs) is one of the most important environmental indicators. The sustainability of wastewater treatment systems can be evaluated in terms of energy consumption based on LCA. The aim of this study was to determine the environmental performance of a biological nutrient removal (BNR) plant in conjunction with mathematical modeling and the LCA approach based on three scenarios, which would reduce the net electricity consumption of the treatment plant by 10%. Three scenarios were constructed by the combinations of different values in dissolved oxygen (DO) concentration, sludge retention time (SRT) and internal recirculation (IR) parameters. A mathematical modeling study was carried out in order to determine the values of those parameters that decreased the net electricity consumption by 10%. Scenario 0 was developed based on a reference WWTP with default DO concentration, SRT and IR. The pairs of SRT and IR; SRT and DO; IR and DO were analyzed in Scenario 1, 2 and 3, respectively. The results showed that the global warming impact category has approximately the same values in Scenario 0 and Scenario 1 and these scenarios have the best performances in this category. Scenario 0 is also the best environmental performing with respect to marine eutrophication, while it has the highest environmental loads in terrestrial ecotoxicity and fossil resource scarcity categories. In freshwater eutrophication, Scenario 1 has the best environmental performance while the highest environmental burden in marine eutrophication is occurred in Scenario 1. Moreover, Scenario 1 and Scenario 2 have the same values and the worst environmental performances in the terrestrial acidification impact category. Scenario 1 and 2 have much better performances in fossil resource scarcity impact than in other scenarios while Scenario 2 is the worst environmental performing with respect to the global warming besides terrestrial acidification. Scenario 3 has a worse environmental performance in the freshwater eutrophication category in comparison to other scenarios, while it has the best environmental performances in the terrestrial acidification and terrestrial ecotoxicity categories. Scenario 1, 2 and 3 have better environmental performances in energy-related impact categories compared to the baseline scenario.

Comparative life cycle assessment of three 2030 scenarios of the Brazilian cement industry.

The cement industry is intensive in energy and feedstock use. It includes three main phases: raw materials and energy supply, transport, and manufacturing. The sector is known for its considerable environmental impacts. The increase in energy efficiency and the use of non-fossil fuels and raw materials are considered mature technologies in cement industries. We evaluate different environmental impacts of the production of 1 t of cement in four Brazilian scenarios. We compare one business-as-usual reference scenario (case 1) to three alternative 2030 carbon mitigation sectoral plan scenarios (cases 2, 3a, and 3b) that assume mature technologies. We analyze all 18 impact categories within the ReCiPe 2016 Life Cycle Assessment methodology. Results show reductions in 17 impact categories, ranging from no change in ozone depletion (case 2) to 39% reduction in fossil resource scarcity (case 3b). The effects on climate change decreased 14% in case 2 and 33% in cases 3a and 3b. The clinkerization process is the greatest contributor to atmospheric impacts, while raw material consumption to toxicity impacts. In contrast, there is no single main process contributing to resource depletion impacts. The changes in cement production lead to carbon emission reductions above expected levels and to reductions in other environmental impact categories modeled in ReCiPe 2016 method.

Life Cycle Environmental Impact Assessment of Sulfur-Based Compound Fertilizers: A Case Study in China

The reduced atmospheric sulfur input has led to sulfur deficiency in plants. Sulfur-based compound fertilizers have been widely used in order to provide necessary sulfate. However, their environmental impacts have been less studied. A life cycle assessment approach is applied to evaluate the environmental impact of sulfur-based compound fertilizers from “cradle to grave”, with a typical fertilizer produced in China as a case study and 1 ton fertilizer as a functional unit. The results show the environmental impacts mainly related to human carcinogenic toxicity, fossil resource scarcity, freshwater eutrophication, freshwater ecotoxicity, terrestrial acidification, and marine ecotoxicity. Synthetic ammonia production, conversion, and fertilizer use processes are the key processes, which contribute 26.6, 18.7, and 23.9%, respectively. Electricity, potassium chloride, hard coal, rock phosphate, and emission pollutants from fertilizer use are key factors, contributing 17.6, 16.0, 14.2, 10.0, and 17.1%, respectively. Sensitivity analysis shows that electricity and potassium chloride are the important factors to be optimized in the overall system. These results can be used to optimize the fertilizer industry and frame policies in order to mitigate the overall environmental impacts of sulfur-based compound fertilizer products under a life cycle framework.

Bioextractive aquaculture as an alternative nutrient management strategy for water resource recovery facilities

Advanced nutrient removal in water resource recovery facilities (WRRFs) can reduce coastal eutrophication, but can increase economic costs and indirect environmental impacts associated with energy and materials usage for WRRF construction and operation. A strategy of interest to reduce coastal eutrophication is the cultivation of seaweeds in proximity to WRRF discharge plumes to bioextract nutrients from coastal waters. We report economic and environmental trade-offs of this proposed strategy for a 1,170 m3·d−1 (0.31 mgd) WRRF in Boothbay Harbor, Maine, targeting a Water Environment Research Federation (WERF) level 2 effluent nitrogen goal of 3 mg-N·L−1. The scenarios investigated include WRRF upgrade and year-round nutrient bioextractive aquaculture (Saccharina latissima and Gracilaria tikvahiae cultivation) with end uses of bioenergy feedstock, fertilizer, or food. Based on biomass production characteristics and tissue nitrogen contents in Boothbay Harbor, an aquaculture site of 5.4 hectares would bioextract equivalent nitrogen mass as WRRF upgrade to meet level 2 nitrogen effluent goals. Using a techno-economic analysis, the cost of a WRRF upgrade was estimated to be $0.31 m−3 wastewater treated. The cost of bioextractive seaweed aquaculture depended on beneficial use of seaweed. If dried and sold as sea vegetables (for human consumption), a net revenue of $0.72 m−3 wastewater treated could be generated. If dried and sold as commercial fertilizer, the net cost of nutrient removal would be $0.26 m−3 wastewater treated, less than the WRRF upgrade. However, if anaerobically digested to produce biogas, the net cost of treatment was estimated to be $0.499 m−3 wastewater treated. WRRF upgrade and bioextractive aquaculture significantly reduced marine eutrophication. Bioextractive aquaculture with use as biofuel feedstock had the best performance on human carcinogenic toxicity, global warming, and fossil resource scarcity, marine ecotoxicity, and freshwater ecotoxicity. Use of seaweed product as sea vegetables was favorable considering human non-carcinogenic toxicity, marine eutrophication, freshwater eutrophication, and terrestrial ecotoxicity. The study results imply that nutrient bioextraction by seaweed aquaculture may be attractive as an alternative to advanced nutrient removal technologies in small coastal WRRFs, providing potential economic and environmental benefits for nutrient management.

Environmental assessment of asphalt mastics containing plastic bottles and jet grouting waste

Apart from the pressing problems of global warming due to outputs of atmospheric gases, the global society is increasingly troubled by the tasks of managing solid waste. In this regard, innovative solutions have been advanced for the reuse of solid waste in non-traditional sectors, including in road asphalt production. The present study investigates the potential production of sustainable superior-performing asphalt mastics (neat bitumen and filler), in which the filler is obtained through procedures of reusing shredded waste plastic (WP) and jet grouting waste (JGW) recovered from soil consolidation activities, rather than traditional limestone filler. A first phase of the study involved the production and the comparison of three asphalt mastics: a mastic containing JGW (JGWM) with a filler over bitumen ratio (f/b) of 0.29, a limestone mastic (LM) blended with an f/b ratio of 0.30 and a mastic containing WP (WPM) made up with an f/b ratio of 0.10. The mechanical characterization was carried out by use of a dynamic shear rheometer for analysis of the rheological performance of the three mastics in terms of rigidity, elasticity and resistance to permanent deformation. A life cycle assessment was conducted using the eighteen impact category indicators of the ReCiPe method, as a means of determining the human and environmental benefits of the innovative hot asphalt mastics. The main results from the mechanical point of view were that, compared to traditional LM: a) at temperatures from 0 to 30 °C, the use of JGW achieved an average 30% greater stiffness; b) at 40 and 50 °C, the WPM reduced permanent deformation by 56%. The most significant outcomes of the environmental analysis were: a) the use of JGWM achieved lower terrestrial ecotoxicity and freshwater eutrophication, respectively 53% and up to 97% less than with LM; b) the WPM achieved 33% and 38% reductions in effects on global warming and fossil resource scarcity, respectively.

Environmental Performance in the Production and Use of Recovered Fertilizers from Organic Wastes Treated by Anaerobic Digestion vs Synthetic Mineral Fertilizers.

Recovered fertilizers (RFs), in the form of digestate and digestate-derived ammonium sulfate, were produced from organic wastes by thermophilic anaerobic digestion (AD) at full scale. RFs were then used for crop production (maize), substituting synthetic mineral fertilizers (SFs). Environmental impacts due to both RF and SF production and use were studied by a life cycle assessment (LCA) approach using, as much as possible, data directly measured at full scale. The functional unit chosen was referred to as the fertilization of 1 ha of maize, as this paper intends to investigate the impacts of the use of RF (Scenario RF) for crop fertilization compared to that of SF (Scenario SF). Scenario RF showed better environmental performances than the system encompassing the production and use of urea and synthetic fertilizers (Scenario SF). In particular, for the Scenario RF, 11 of the 18 categories showed a lower impact than the Scenario SF, and 3 of the categories (ionizing radiation, fossil resource scarcity, and water consumption) showed net negative impacts in Scenario RF, getting the benefits from the credit for renewable energy production by AD. The LCA approach also allowed proposing precautions able to reduce further fertilizer impacts, resulting in total negative impacts in using RF for crop production. Anaerobic digestion represents the key to propose a sustainable approach in producing renewable fertilizers, thanks to both energy production and the modification that occurs to waste during a biological process, leaving a substrate (digestate) with high amending and fertilizing properties.

Environmental assessment of the production of itaconic acid from wheat straw under a biorefinery approach

This study performs the environmental assessment of itaconic acid (IA) production from wheat straw. The Life Cycle Assessment (LCA) methodology is used to determine the environmental hotspots, considering impact categories such as Global Warming (GW), Fossil Resource Scarcity (FRS), Water Consumption (WC), among others. A sensitivity analysis was performed considering an optimization of the steam explosion process and 100% renewable energy. Results report an impact of about 14.33 kg CO2 eq in GW, 4.15 kg of oil eq in FRS, for each kg of IA produced for the baseline scenario. Moreover, the pretreatment and fermentation stages constitute hotspots of the IA production. In addition, using a renewable energy source in production would reduce the impact by 82% in GW, 71% in PM and 82% in FRS categories. The optimization of the steam explosion process presents a better performance in GW and FRS but also lies in an increase in WC.

Cradle-to-grave life cycle assessment of production and consumption of pulses in the United States

Environmental impact associated with production and consumption of pulses in the United States was evaluated using life cycle assessment (LCA). The system boundary was set to cradle-to-grave with a functional unit of 60 g (dry basis) of pulses consumed in a US household. Varieties of pulses modeled in the study included field pea (Pisum sativum), lentil (Lens culinaris), chickpea (Cicer arietinum), and dry bean. Three methods of cooking pulses at the consumer stage tested in the study were cooking in open vessel on electric cooking range (OVC), cooking in stovetop pressure cooker on electric cooking range (SPC), and cooking in electric pressure cooker (EPC). OVC formed the base scenario against which all other scenarios were compared. The environmental impact of pulses varied with type of pulse crop, cooking method, and the batch size. Consumption of approximately 60 g of dry pulses resulted in the greatest environmental impact for OVC. The consumer stage contributed at least 83, 81, 76, 75, and 87 percent for global warming potential (GWP), fossil resource scarcity (FRS), water consumption (WC), freshwater eutrophication (FE), and marine eutrophication (ME), respectively for this scenario. EPC resulted in the greatest decrease in the environmental impact, compared to OVC, for GWP, FRS, FE, and ME for all pulse varieties, which was validated in the uncertainty analysis. SPC, on the other hand, decreased the impact across these categories only for chickpea and dry bean. The uncertainty analysis suggested that the differences associated with cooking methods in the mean land use and water consumption scores of pulses were statistically non-significant. The impact categories were also highly sensitive to the mass of pulses cooked in a batch. Increasing the reference flow in OVC to 1 kg decreased the environmental impact of pulses by 49–87 percent for all impact categories, excluding land use. Overall, the study identified the consumer stage as the hotspot for environmental impact in the supply chain of pulses in the United States. The large contribution of the consumer stage to the overall environmental impact of pulses was attributed to electricity consumption for cooking and associated upstream emissions.

Environmental life cycle assessment of cow milk in a conventional semi-intensive Brazilian production system.

The environmental performance of cow milk produced in a conventional semi-intensive system was assessed using a cradle-to-farm gate attributional life cycle assessment. The impacts of 1 kg FPCM—fat and protein corrected milk were obtained considering six midpoint impact categories from the ReCiPe 2016 method: climate change (CC), terrestrial acidification (TA), freshwater eutrophication (FE), land use (LU), water consumption (WC), and fossil resource scarcity (FRS). The modeling of the product system and calculating the environmental impacts considered the use of SimaPro™ software. Enteric methane and nitrogen emissions and inputs for feeding animals (fertilization for pasture production, use of seed in corn crops, and milk replacer in calves feed) were the main contributors to impacts in milk production in most categories. In addition, the indirect energy use and wastewater generation in milking and milk cooling also were relevant. Literature-based strategies are suggested to mitigate the identified environmental impacts to achieve the best environmental performance without decreasing technical and quality milk production. We emphasize the importance of improving productivity per milk cow, knowing the origin of the supply chain inputs, and using it efficiently to produce animal feeds as the main strategies to improve milk's environmental performance. Changes in allocation methods did not substantially differ in impact categories. Sensitivity analysis foregrounds the consistency of results and conclusions of the current study despite the uncertainties associated with methodological choices, simplifications, suppositions, and the use and adaptation of international databases.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-17317-5.

Life cycle assessment and life cycle cost analysis of compound microbial fertilizer production in China

Compound microbial fertilizer (CMF) uses organic waste as a raw material and is an environmentally friendly alternative to conventional chemical fertilizers. However, further analyses of the environmental performance of CMF production are necessary. This study first evaluated the environmental impacts of CMF made from chemical fertilizers, organic wastes, and microorganisms, as well as economic costs. A case study, whose scope encompassed raw materials, transportation, and manufacturing stages was conducted on a fertilizer company in the Hubei Province of China through a combined “cradle-to-gate” life cycle assessment and life cycle cost methodology. Normalization of midpoint results indicated that impacts on fossil resource scarcity, water consumption, and terrestrial acidification are key contributors to the total impacts. The key stage analysis highlighted that the raw materials stage played a critical role (more than 48%) in the environmental performance of the CMF life cycle, followed by the transportation and manufacturing stages (less than 15%). Key substance analysis showed that monoammonium phosphate use is a hotspot and significantly increases the environmental burden of CMF production. Moreover, bentonite and pig manure were also identified as the key substances. Future improvements in the supply chain should focus on monoammonium phosphate, bentonite production, and pig manure extraction. Results of the sensitivity analysis confirmed that controlling pollution from monoammonium phosphate and bentonite should be a priority in realizing clean production. Additionally, an economic analysis indicated that the life cycle cost of CMF was 675.75 CNY/t and that raw material costs contributed the most to the total life cycle cost (over 70%). On the basis of these results, possible recommendations were proposed, such as promoting green procurement of main raw materials, improving the collection technology of pig manure, and extending the scale of CMF enterprises. This study can be significant in assisting relevant stakeholders with decision-making to ensure a balanced tradeoff between an environmentally friendly option and an economically feasible option.