Terms Of Global Warming Potential Research Articles

Environmental Life-Cycle Assessment of Eco-Friendly Alternative Ship Fuels (MGO, LNG, and Hydrogen) for 170 GT Nearshore Ferry

With increasing concerns about environmental pollution, the shipping industry has been considering various fuels as alternative power sources. This paper presents a study of the holistic environmental impacts of eco-friendly alternative ship fuels of marine gas oil (MGO), liquefied natural gas (LNG), and hydrogen across each of their life cycles, from their production to the operation of the ship. The environmental impacts of the fuels were estimated by life-cycle assessment (LCA) analysis in the categories of well-to-tank, tank-to-wake, and well-to-wake phases. The LCA analysis was targeted for a 170 gross tonnage (GT) nearshore ferry operating in the ROK, which was conceptually designed in the study to be equipped with the hydrogen fuel cell propulsion system. The environmental impact performance was presented with comparisons for the terms of global warming potential (GWP), acidification potential (AP), photochemical ozone creation potential (POCP), eutrophication potential (EP), and particulate matter (PM). The results showed that the hydrogen showed the highest GWP level during its life cycle due to the large amount of emissions in the hydrogen generation process through the steam methane reforming (SMR) method. The paper concludes with suggestions of an alternative fuel for the nearshore ferry and its production method based on the results of the study.

Life-cycle assessment approach for municipal solid waste management system of Delhi city

The life-cycle assessment (LCA) approach with route optimization technique was adopted in the present study to evaluate environmental and economic aspects associated with the prevalent waste management system in Delhi city. With an objective of cost minimization and abating environmental hazards from waste transportation systems, ArcGIS was used to identify the most appropriate route for waste transportation. The study was conducted considering four landfills located at Bawana, Bhalswa, Ghazipur and Okhla present in Delhi city. Landfilling, composting, anaerobic digestion, and recycling methods were analyzed for global warming potential (GWP), eutrophication potential (EP), acidification potential, abiotic resource depletion potential and photochemical oxidation potential parameters using LCA software GaBiPro. The results from the LCA studies for the municipal solid waste management system of Delhi city revealed that transportation emissions and landfilling negatively impact the environment. The effect of recycling rate on the landfilling, composting, anaerobic digestion was also studied using sensitivity analysis. Results of sensitivity analysis depicted that recycling of waste is inversely related to the impact categories. Overall, the results exhibited a detrimental effect of landfilling on the environment in terms of GWP and EP. Further, considering the geospatial analysis, two waste recycling stations are proposed in the vicinity of existing waste management plants to reduce the time and cost of waste transport from the landfills to the waste management plants.

Waste-to-energy innovative system: Assessment of integrating anaerobic digestion and pyrolysis technologies

Anaerobic digestion (AD) of sewage sludge is an already well-developed technology to convert waste to bioenergy and digestate. Despite its deployment, AD process still raises environmental, technical and economic issues and many researches have been done to improve the process yield, reduce environmental burdens from digestate application and allow a better distribution of energy. The integration of thermal processes with anaerobic digestion is explored to overcome some of the anaerobic digestion limitations. In this study, a cradle-to-grave life cycle assessment (LCA) is performed to compare a system integrating anaerobic digestion and pyrolysis (PY) with single anaerobic digestion, for the co-digestion of sewage sludge and quinoa residue. The results suggest that the environmental impacts of the two pathways are quite similar except for three impact categories: single anaerobic digestion is the best scenario in terms of global warming potential (−769 vs. -604 kg CO 2 eq./t substrate), ozone depletion (−33.7 vs −2.11 mg CFC-11 eq./t substrate) and fossil resources use (−9900 vs −6900 MJ/t substrate). The multifunctional process could be a viable competitor to single anaerobic digestion by improving pyrolysis products upgrading. The application of liquid digestate to crop field revealed to have significant burdens to particulate matter, acidification and terrestrial eutrophication impact categories and must be carefully monitored in both pathways.

DIR-FCEV powered by different fuels – Part I: Well-to-wheel analysis for the Brazilian and Spanish contexts

This article describes the life cycle assessment of the Direct Internal Reforming Fuel Cell Electric Vehicle (DIR-FCEV) for the Brazilian and Spanish contexts. This recently proposed vehicle technology produces hydrogen onboard via heat recovery, while the Solid Oxide Fuel Cell (SOFC) and the gas turbine provide electricity to the electric motor with high overall efficiency. The exhaust gas emission was obtained via GASEQ software and the well-to-tank data were collected through literature search. These values were entered in the GREET Model software version v1.3.0.13656 to assess the negative environmental impacts of the DIR-FCEV in terms of global warming potential (GWP) and human toxicity potential (HTP). Using 1 km distance driven by a light-duty vehicle as the functional unit, the tank-to-wheel results indicate that regardless of the fuel, the DIR-FCEV achieved better than the internal combustion engine vehicle fuelled with gasoline A in both categories. Also, the DIR-FCEV powered by biomethane, gasoline A, gasoline C (73% gasoline A and 27% ethanol, in volume basis), glycerine, and ethanol attended all future tailpipe emissions standards stipulated by United States and European Union. Biomethane and gasoline-fuelled DIR-FCEV had more commendatory environmental performance in both countries. Thus, it is expected to obtain environmental indicators to stimulate the use of biofuels synergistically with the advancement of electromobility in Brazil and Spain.

Dietary Patterns at the Individual Level through a Nutritional and Environmental Approach: The Case Study of a School Canteen.

The public catering sector has important responsibilities in seeking a change toward more sustainable choices for many aspects related to the environmental impacts of their services. The environmental impact of production processes can be studied through life cycle assessment (LCA), which allows a greater awareness of choices and has rarely been applied to catering. In this work, we studied the impacts of two dishes (braised meat and cauliflower meatballs) in a school canteen, their impacts were studied using the daily energy requirement (expressed in kcal) as a functional unit. Global warming potential (GWP) and nonrenewable energy (NRE) were calculated starting from the supply of raw materials up to distribution. Electricity and the act of cooking the meatballs accounted for more than 60% of the measured impact in terms of GWP, whereas, less markedly, they dominated in terms of nonrenewable energy used. In the case of braised meat, the total impact was, however, attributable to the life cycle of the meat (between 60% and 76%) and the consumption of electricity (between 19% and 27%), whereas for all other factors, the contribution was never particularly high. Additionally, a discussion on the correct functional unit to be used proposed the environmental impact of different recipes as an additional criterion for nutritionists during the composition of the menu. An integrated system appears important for changing policies and behaviors and the application of LCA can be a tool capable of contributing to the construction of a holistic instrument of sustainability.

Techno-environmental-economic assessment on municipal solid waste to methanol coupling with/without solid oxygen electrolysis cell unit

Integrating municipal solid waste (MSW) gasification with renewable energy to synthesize methanol shows great potential in alleviating the dependence on fossil energy and reducing the negative environmental impact of increasing MSW production. In this study, three technological processes including MSW-to-methanol integrated with carbon capture and storage (MTMC), MSW-to-methanol integrated with solid oxygen electrolysis cell unit (MTMS) and MSW incineration to power (MTP) are compared from the perspective of techno-environmental-economic performance. Results show that MTMS process owns the maximum exergy efficiency (60.8%), followed by MTMC (41.5%) and MTP (18.9%). In terms of global warming potential (GWP), MTP process has the worst environmental performance with 19,164.84 kgCO2eq/h. The economic analysis shows that MTMS process owns the highest value of levelized profit of MSW (LPOM) with 38.64 USD/t under the current market conditions. In addition, comparative analysis shows the production cost of methanol (PCOM) of MTMC and MTMS routes is 406.09 USD/t and 355.89 USD/t, respectively, which are economically competitive compared with the coal / biomass / CO2 hydrogenation to methanol route. Sensitivity analysis shows that MTMS process processes its advantage on economic performance only if the methanol price is higher than 350 USD/t and photovoltaic on-grid tariff is lower than 0.055 USD/kWh.

Environmental performance of the innovative, patented mixing system in an agricultural biogas plant based on LCA approach

Renewable energy production in biogas plants seems to be recognised in literature from the environmental perspective. However, innovative technologies are still launched to improve energy efficiency. In this perspective, the authors developed the patented hybrid pump to improve the yield of methane production and reduce the environmental impact of renewable energy production. This research assesses the environmental performance of an innovative, patented hybrid pump designed for mixing the input of anaerobic digestion of pig slurry, based on the Life Cycle Assessment (LCA) approach. The comparative environmental analysis of two different mixing systems installed in the pilot biogas plant was conducted on the basis of the selected impact categories. The application of innovative mixing technology with a hybrid pump increased the percentage yield of methane in biogas from slurry by about 10% compared to a conventional hydraulic pump. The application of a hybrid pump in the tested biogas plant reduced the Cumulative Energy Demand (CED) ratio by almost 30% compared to a conventional hydraulic pump. A similar level was obtained for other environmental impact ratios in terms of global warming potential, abiotic depletion of fossil fuels, human toxicity, acidification, and eutrophication.

Environmental and Biological Impact of Fly Ash and Metakaolin-Based Alkali-Activated Foams Obtained at 70°C and Fired at 1,000°C

Alkali-activated foams (AAFs) are inorganic porous materials that can be obtained at temperatures well below 100°C with the use of inorganic wastes as aluminosilicate precursors. In this case, fly ash derived from a Slovenian power plant has been investigated. Despite the environmental benefits per se, due to saving of energy and virgin materials, when using waste materials, it is of extreme importance to also evaluate the potential leaching of heavy metal cations from the alkali-activated foams. This article presents an environmental study of a porous geopolymer derived from this particular fly ash, with respect to the leachability of potentially hazardous elements, its environmental toxicity as determined by biological testing, and the environmental impact of its production. In particular, attention was focused to investigate whether or not 1,000°C-fired alkali-activated fly ash and metakaolin-based foams, cured at 70°C, are environmentally friendlier options compared to unfired ones, and attempts to explain the rationale of the results were done. Eventually, the firing process at 1,000°C, apart from improving technical performance, could reinforce heavy metal cation entrapment within the aluminosilicate matrix. Since technical performance was also modified by addition of different types of activators (K-based or Na-based), as well as by partial replacement of fly ash with metakaolin, a life cycle assessment (LCA) analysis was performed to quantify the effect of these additions and processes (curing at 70°C and firing at 1,000°C) in terms of global warming potential. Selected samples were also evaluated in terms of leaching of potentially deleterious elements as well as for the immobilization effect of firing. The leaching test indicated that none of the alkali-activated material is classified as hazardous, not even the as-received fly ash as component of new AAF. All of the alkali-activated foams do meet the requirements for an inertness. The highest impact on bacterial colonies was found in samples that did not undergo firing procedures, i.e., those that were cured at 70°C, which induced the reduction of bacterial Enterococcus faecalis viability. The second family of bacteria tested, Escherichia coli, appeared more resistant to the alkaline environment (pH = 10–12) generated by the unfired AAMs. Cell viability recorded the lowest value for unfired alkali-activated materials produced from fly ash and K-based activators. Its reticulation is only partial, with the leachate solution appearing to be characterized with the most alkaline pH and with the highest ionic conductivity, i.e., highest number of soluble ions. By LCA, it has been shown that 1) changing K-based activators to Na-based activators increases environmental impact of the alkali-activated foams by 1%–4% in terms of most of the impact categories (taking into account the production stage). However, in terms of impact on abiotic depletion of elements and impact on ozone layer depletion, the increase is relatively more significant (11% and 18%, respectively); 2) replacing some parts of fly ash with metakaolin also results in relatively higher environmental footprint (increase of around 1%–4%, while the impact on abiotic depletion of elements increases by 14%); and finally, 3) firing at 1,000°C contributes significantly to the environmental footprint of alkali-activated foams. In such a case, the footprint increases by around one third, compared to the footprint of alkali-activated foams produced at 70°C. A combination of LCA and leaching/toxicity behavior analysis presents relevant combinations, which can provide information about long-term environmental impact of newly developed waste-based materials.

Life cycle assessment of the production of beet sugar and its by-products

This work presents estimates of the emissions resulting from the production of white sugar and its by-products (molasses, pressed beet pulp and dried beet pulp) from sugar beet cultivation to the final product at the factory gate. The study covers the impact of global warming potential, eutrophication potential (freshwater and marine) and particulate matter. The analysis was based on detailed primary data provided by Nordic Sugar A/S, from the Örtofta Sugar Factory (southern Sweden). The results of this analysis are presented for the functional unit of 1 tonne (t) white sugar without allocation. Economic and energy allocations were also applied and compared for white sugar and its by-products. The allocation of emissions to the product and by-products reduced the emissions for white sugar by 9% in the economic allocation, and by 21% in the energy allocation. The low economic value of the by-products gave rather low emissions for all by-products when applying economic allocation. These results were compared with those in the literature for white sugar in terms of global warming potential (GWP), and the results showed the lowest impact for both allocations. Replacing fossil natural gas as the main process energy source with softwood chips reduced the GWP for white sugar (without allocation to by-products) from 623 to 342 kg CO2eq/t, illustrating the considerable potential for greenhouse gas emission reduction by replacing fossil fuels in the production process.

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.

Life-cycle assessment of solid waste management in Dhulikhel Municipality, Nepal

Solid waste management is becoming a major environmental and public health concern in emerging municipalities in Nepal. In this study, the life-cycle assessment (LCA) approach is used to address the environmental impacts of potential waste-treatment scenarios in Dhulikhel Municipality in Nepal. The assessment was based on four different scenarios – namely, scenario 1, landfilling; scenario 2, composting combined with landfilling; scenario 3, recycling, composting and landfilling; and scenario 4, recycling, anaerobic digestion and landfilling. The LCA methodology was developed, including the benefits and impact potentials of different unit processes in each scenario, also taking into consideration emissions from energy use. The environmental impacts from the scenarios were compared in terms of global warming potential, acidification potential and eutrophication potential. Among the four scenarios, scenario 4 (i.e. with anaerobic digestion) showed the most environmental advantage. Scenarios without biological treatment facilities are the least preferred option, as their impact is significantly greater than those of other options. Therefore, organic waste is recommended not to be disposed of in landfill sites even if the transportation activity increases, because the magnitude of methane avoidance increases with an increased amount of waste diversion to the biological treatment units.

Live-Life cycle assessment of the electric propulsion ship using solar PV

This paper was born to introduce a novel methodology termed Live-Life Cycle Assessment using a simulation-based data generation technique that can remedy the inherent shortcomings of conventional practices of lifecycle assessment. To demonstrate its excellence, the proposed method was applied to one of the most challenging topics in the marine industry. That was to tackle the fundamental doubt of whether solar-electric propulsion ships could truly be the future energy solution of maritime transports by fulfilling new environmental conventions and goals around the world. The case study began with an existing hybrid short route ferry running on diesel and plug-in battery power. Credible PV systems for the case ship was modelled to produce ship performance data under various operational/environmental circumstances of the coastal zones across 29 countries in the platform of MATLAB/Simulink. As a key functionality of Live-Life Cycle Assessment, the produced data was directly fed, as inputs, into life cycle assessment to avoid conventional practices that heavily rely on outdated data libraries. Results of the case study clearly revealed and quantified the correlations of the performance of PV-battery systems with climate parameters such as temperature and irradiance of subject areas as well as national power production methods. For example, in terms of Global Warming Potential, the case ship with the PV system was estimated to reduce 40,812 kg CO2 eq. per year in Brazil (average temp.: 27.4 ℃, major energy source: hydro). Interestingly, the same vessel was found to achieve greater reductions in India (average temp.: 27.5 ℃, major energy source: coal) or Australia (average temp.: 20.1 ℃, major energy source: coal) where are overly laden with coal-based power plants. Therefore, their reduction levels were estimated at 152,887 kg CO2 eq. per year and 141,517 kg CO2 eq. per year respectively. This paper clearly shows the excellence of the proposed method to demystify/quantify the impacts of parametric variables on the performance of the PV-electric ship. Moreover, it highly suggests the Live-Life Cycle Assessment could be a solution as a new standard to respond to strong demand to obtain general observation of lifecycle benefits/harms of new technologies across all industries, not necessarily limited to the maritime sector.

Life cycle assessment of biogas production from mixtures of vinasse and concentrated latex wastewater

Environmental impacts of biogas production were evaluated by a life cycle assessment (LCA) of mixtures of vinasse and concentrated latex wastewater (CLWW) as: 1) single-stage and two-stage anaerobic digestion with different ratios and initial pH; 2) LCA of thermal energy from biogas. Results showed that almost all two-stage anaerobic digestion processes produced higher amounts of biogas and methane than the single-stage. Environmental impact was assessed for 1 MJ of thermal energy production. Two-stage anaerobic digestion produced less environmental impact in terms of global warming potential (GWP), acidification (AD) and energy use (EU) than single-stage at 64.82, 64.86 and 64.72%, respectively. Anaerobic digestion significantly contributed to environmental impact using sodium hydroxide solution for pretreatment.

Energy performance of a compression refrigeration cycle using environment-friendly refrigerants

An integrated power and cooling cycle is planned, which is theoretically analyzed with various working fluids to evaluate the performance, and also the environmental impact of the selected fluids is discussed. The proposed cycle has the cooling system as Vapour compression refrigeration and power cycle as Organic Rankine Cycle. Both the cycles are using the same fluid and the cycles are physically combined. Hence, the power and cooling cycles have been combined as a single cycle. Working fluids are selected under the condition that they can work on both cycles. It was also important to make it necessarily certain that the fluid attained a superheated state after compression in Vapour compression refrigeration and after expansion in Organic Rankine Cycle. The performance of the cycle is analyzed for the selected fluid under normal operating conditions. Since there is significant variation in the maximum and minimum values of critical temperatures for each of the selected fluids, a common interval of maximum and minimum temperature cannot be assigned to all the fluids for the cycle. The cycle has been analyzed for the following conditions, first by fixing the refrigeration capacity alone, second by fixing the turbine output alone, and also by varying the condenser temperature. The obtained COP values vary from 1.7 to 3.14. The maximum COP value obtained for R124 refrigerant is 3.14 at an evaporator temperature of −24 ℃. Similarly, the efficiency of the power cycle is varied from 18% to 25%. The refrigerant R114b holds the maximum value of 25.18% at a boiling temperature of 197℃.. The environmental effect of the chosen working fluids is examined in terms of Global warming potential, ozone depletion potential, toxicity, and flammability.

Life Cycle Assessment Model for Biomass Fuel Briquetting

Previous Life Cycle Assessment (LCA) studies of biomass briquetting have shown wide variations in the LCA outcomes as a result of variations in LCA methodological parameters and briquetting technological parameters. An LCA model of biomass briquetting was therefore developed to enable transparent comparison of life cycle environmental impacts of briquetting with individual or blends of biomass feeds with a variety of technological options. The model was developed according to the standard LCA procedure of ISO14044. A comparative approach was utilised, and a set of integrated excel worksheets that describe process flows of material, energy and emissions across different units of the briquetting process was used in developing the model components. The main model components include materials and process inventory databases derived from standard sources, main process calculations, user inputs and results sections. The model is open-access in a user accessible format (Microsoft Excel). A representative case study with mixed rice husks and corn cobs was used in validating the model. Results showed that the briquetting unit made the largest contribution, 42%, to the total life cycle operational energy of the briquetting system. For all the blends of rice husks and corn cobs explored in this study, the total life cycle energy of briquetting was in the range 0.2 to 0.3 MJ/MJ. For the same blend ratios, a total life cycle energy of briquetting in the range 0.2 to 1.7 MJ/MJ was also obtained with change in other LCA input parameters, in a sensitivity test. An increase in rice husk content of the blend increased the environmental impact of briquetting in terms of global warming potential (kg CO2-eq), acidification potential (kg SO2-eq), human toxicity (kg 1,4-DB-eq), ozone layer depletion (kg CFC-11-eq), and terrestrial ecotoxicity (kg 1,4-DB-eq) per MJ briquette energy content, as it was associated with a lower briquette density, which increased the energy required for handling.

Environmental Performances of Various CCU Options in the Framework of an Integrated Chemical Plant.

Several carbon capture processes are investigated to separate a part of the CO2 contained in the flue gas of a coal-fired power plant located in a chemical integrated plant, with the objective of using it as a raw material in a production process. The expected results are to reduce the impact on global warming potential (GWP) and to increase the productivity of the plant. The study is based on the modelling of the combination of systems in the plant using a process simulation software and using life cycle assessment to evaluate both technical feasibility and environmental aspects. Models for the power plant, the production processes, amine chemical absorption, membrane separation and adsorption on activated coal are developed and validated against industrial and literature data. The life cycle inventory is obtained from the mass and energy balances given by the systems model. A first set of calculations is launched with a high purity requirement for the CO2 stream (95%) recycled into the process. Those calculations show a 12% increase in productivity for the chemical process considered, but result in no significant gain in terms of GWP. Conversely, scenarios with a lower CO2 purity (40%) show a drop around 9% of the impacts on GWP using membrane separation and activated coal adsorption, while keeping the other impacts at about the same level.

Circular economy strategy of reusing olive mill wastewater in the ceramic industry: How the plant location can benefit environmental and economic performance

The olive mill wastewater (OMWW) is one of the highly pollutant residue in olive oil producing countries around the Mediterranean Sea, due to its large organic load and the presence of a variety range of contaminants. The valorization and the recycling of this by-product can represent a successful strategy for the implementation of circular economy models in the agri-food industry. For this purpose, the incorporation of OMWW in the brick-making process represents a promising solution, which not only can avoid the impacts due to its disposal but also reduce the heat required during the ceramic production process, resulting in lower greenhouse gas emissions and economic benefits. However, many factors should be considered, including the transport activity of the OMWW from the mill to the factory that can affect both the environmental and economic benefits. The present study aims to assess the performance of an open-loop circular economy system based on the reuse of the OMWW in the fired clay brick production, in terms of technical feasibility, environmental and economic sustainability. To evaluate environmental impacts, a comparative Life Cycle Assessment is performed between a conventional production and a system in which OMWW is directly integrated in the brick-making process, considering scenarios with different transport distances. Furthermore, an economic sensitivity analysis was implemented, taking into account energy savings and the additional costs due to transport. The results showed that the overall Global Warming Potential (GWP) decreases up to 3.1% for OMWW-based bricks with respect to conventional ones, as well as the Abiotic Depletion of fossil fuels is reduced by 4.3%. On the other hand, no significant variations were observed for the toxicity impact category, that ranges from −1.1% to 0.7%. Furthermore, the water consumption increases for OMWW-based brick production up to 7.8%. Finally, in terms of GWP, it has been found that to make the benefits persist, the oil mill should be placed in a distance of less than 150 km from the brick factory, indicating a more restrictive constraint than the economic one, corresponding to a distance of 207 km.

Environmental Life Cycle Assessment of Ammonia-Based Electricity

In recent years, several researchers have studied the potential use of ammonia (NH3) as an energy vector, focused on the techno-economic advantages and challenges for full global deployment. The use of ammonia as fuel is seen as a strategy to support decarbonization; however, to confirm the sustainability of the shift to ammonia as fuel in thermal engines, a study of the environmental profile is needed. This paper aims to assess the environmental life cycle impacts of ammonia-based electricity generated in a combined heat and power cycle for different ammonia production pathways. A cradle-to-gate assessment was developed for both ammonia production and ammonia-based electricity generation. The results show that electrolysis-based ammonia from renewable and nuclear energy have a better profile in terms of global warming potential (0.09–0.70 t CO2-eq/t NH3), fossil depletion potential (3.62–213.56 kg oil-eq/t NH3), and ozone depletion potential (0.001–0.082 g CFC-11-eq/t NH3). In addition, surplus heat for district or industrial applications offsets some of the environmental burden, such as a more than 29% reduction in carbon footprint. In general, ammonia-based combined heat and power production presents a favorable environmental profile, for example, the carbon footprint ranges from −0.480 to 0.003 kg CO2-eq/kWh.

Dairy Buffalo Life Cycle Assessment (LCA) Affected by a Management Choice: The Production of Wheat Crop

Life cycle assessment (LCA) was performed in dairy buffalo farms representative of Southern Italian farming systems, similar due to several characteristics, with the exception of wheat production. This work evaluated the impacts derived from this management choice, comparing farms with wheat crop (WWC) or not (NWC). In agreement with the literature, economic allocation was chosen as a useful strategy to attribute equivalents to by-products, i.e., culled animals; the same criterion was also adopted to assign pollutants to wheat grain, limited to WWC farms. Environmental impacts in terms of Global Warming Potential (GWP, kg CO2 eq), Acidification Potential (AC, g SO2 eq), Eutrophication Potential (EU, g PO43-eq), Agricultural Land Occupation (ALO, m2y) and Water Depletion (WD, m3) were estimated. The production of wheat crop significantly affected (p < 0.05) the Agricultural Land Occupation (ALO) category as WWC farms need adequate land. WWC farms could allow a significant reduction in eutrophication (EU) compared to NWC farms (p < 0.05).

Life cycle assessment of sewage sludge pyrolysis: environmental impacts of biochar as carbon sequestrator and nutrient recycler

The pyrolysis of sewage sludge is an alternative method to recycle the contained nutrients, such as phosphorus, by material use of the resulting biochar. However, the ecological effects of pyrolysis are not easy to evaluate. Therefore, a life cycle assessment (LCA) was carried out to determine the environmental impact of sewage sludge pyrolysis and to compare it with the common method of sewage sludge incineration. In order to identify the most sustainable applications of the resulting biochar, four different scenarios were analyzed. The modeled life cycles include dewatering, drying and pyrolysis of digested sewage sludge and utilization paths of the by-products as well as various applications of the produced biochar and associated transports. The life cycle impact assessment was carried out using the ReCiPe midpoint method. The best scenario in terms of global warming potential (GWP) was the use of biochar in horticulture with net emissions of 2 g CO2 eq./kg sewage sludge. This scenario of biochar utilization can achieve savings of 78% of CO2 eq. emissions compared to the benchmark process of sewage sludge mono-incineration. In addition, no ecological hotspots in critical categories such as eutrophication or ecotoxicity were identified for the material use of biochar compared to the benchmark. Pyrolysis of digested sewage sludge with appropriate biochar utilization can therefore be an environmentally friendly option for both sequestering carbon and closing the nutrient cycle.