Terrestrial Acidification Potential Research Articles

Multi-criteria analysis of strategies towards sustainable recycling of phosphorus from sewage sludge in Austria

To promote optimal phosphorus (P) recovery from municipal wastewater and sewage sludge with viable legal instruments, it is imperative to understand the regional and national consequences of different legal requirements for recycling. In this study we develop a scenario-based analysis to assess the environmental and economic impact of different national P recovery strategies in the context of a detailed representation of the existing Austrian wastewater infrastructure. This assessment combines material flow analysis, life cycle assessment and life cycle costing and includes the indicators P recycling rate, P utilization degree, heavy metal removal rate, share of heavy metals’ content in wastewater redirected to agricultural soils, global warming potential, cumulated energy demand, terrestrial acidification potential, volume of freight transport and annual costs. The following main conclusions can be drawn. P recovery from ash shows the highest potential regarding the utilization of P from wastewater. A high P utilization from wastewater should rely on recovery technologies that decontaminate products, otherwise pollutant loads to agricultural soils might increase. P recovery to the extent of 60–85 % of P in WWTPs influent can be achieved by savings/costs of −0.8 to +4.7 EUR inhabitant−1 yr−1 in addition to current cost of the wastewater treatment/sludge disposal system. Key factors to be considered for costs are the choice of recovery process, revenues from products, and the use of existing incineration infrastructure. P recovery can lead to the reduction of greenhouse gas emissions in Austria if nitrous oxide emissions from sludge incineration are limited and efficient heat utilization strategies are implemented. There is a trade-off in terms of environmental and economic costs in choosing a more centralized or decentralized mono-incineration strategy.

Techno-Environmental Evaluation of Alkaline Treatment in Flax Reinforced Thermoplastics.

A combination of thermoplastics and natural fiber reinforcements is considered an ideal choice to mitigate environmental impacts and enhance recyclability or reusability. Chemical treatments are often employed to enhance the thermomechanical properties of natural fiber-reinforced plastics. Nevertheless, it is of paramount importance to assess the techno-economic impact of such chemical treatments and environmentally friendly materials for their implementation in mass productions on an industrial scale. In this work, high-density polyethylene is reinforced with sodium hydroxide (NaOH)-treated and untreated flax fibers to study its impact on mechanical and environmental properties. The composites treated with NaOH exhibited a 37% increase in tensile strength. However, life cycle assessment performed on the NaOH-treated samples showed that they had a global warming potential of 5.8 kg of CO2, a terrestrial acidification potential of 0.0269 kg of SO2, and a human carcinogenic toxicity of 0.031 kg of 1,4-DCB compared to the untreated samples. In summary, the techno-environmental analysis reveals a novel approach to identifying chemical treatments based on their technical and environmental effects.

Life cycle assessment of SBS modified bitumen waterproofing membrane

Building waterproofing membranes constitute essential components of construction materials. This study utilizes the life cycle assessment (LCA) methodology to develop a comprehensive life cycle inventory and conduct an environmental impact assessment of typical styrene-butadiene-styrene (SBS) modified bitumen waterproofing membrane products. The main research objective of this paper is to identify the key factors influencing the environmental impact of products and to provide data for the selection of green materials in the construction industry. The results reveal that the production of raw materials for SBS-modified bitumen waterproofing membranes contributes the most to all environmental impact categories, followed by the transportation and energy production stages, while the production stage of the membranes exhibits a relatively smaller contribution. Within the raw material production stage, the bitumen production process exhibits the highest contribution to fossil fuel depletion (FFP) environmental impact, surpassing 50%. The production process of polyester tire cloth demonstrates the greatest influence on human toxicity potential (HTPc), global warming potential (GWP), freshwater eutrophication (FEP), marine eutrophication potential (MEP), and mineral resource scarcity potential (SOP), accounting for 54.63%, 32.86%, 68.55%, 72.41%, and 61.69%, respectively. Additionally, the production process of base oil exhibits the most significant contribution to fine particulate matter formation (PMFP) and terrestrial acidification potential (AP) among the environmental impact indicators. Variations in the quantities of polyester tire cloth and base oil exhibit the most notable influence on the environmental indicators of the product. Specifically, the sensitivity analysis reveals that polyester tire cloth has the greatest impact on mineral resource scarcity potential (SOP); base oil exhibits the highest sensitivity to fossil fuel depletion (FFP).

Environmental assessment of road transport fueled by ammonia from a life cycle perspective

Renewable energy penetration into the electricity market has been increasing over the last decades; however, it is a different story in the transport sector. Fossil fuels are still predominant; therefore, several alternatives are being studied to attain a low-carbon, more sustainable transport and, consequently, a sustainable society. Ammonia has the potential to be a viable option, and it is critical to study its environmental profile in this early phase to appraise its sustainability as a fuel for passenger road transportation. This work aimed to develop a life cycle assessment of an ammonia-fueled internal combustion engine passenger car from the cradle to the grave, considering 1 km traveled as the basis for comparison. The product system under study included four stages: (i) vehicle, (ii) infrastructure, (iii) energy production, and (iv) operation. Life cycle inventory data related to vehicle operation, specifically ammonia combustion, resulted from various simulations of a model that considered the effect of different operation modes and vehicle emission control strategies, which resulted in nine configurations. The results show that rich mixtures (with an equivalence ratio of 1.1) help to reduce both nitrogen oxides (NOX) and nitrous oxide (N2O) emissions. As for unburnt ammonia (NH3), the after-treatment system drastically diminishes these and NOX emissions. Data on infrastructure and other upstream processes was taken from the Ecoinvent 3.7.1 database, and the ammonia production was based on the life cycle inventory from previous research. The life cycle impact assessment was performed on OpenLCA software implementing the ReCiPe2016 Midpoint (H) v1.13 methodology. On average, per 1 km traveled in an ammonia-based ICEV represents 0.098 kg CO2-eq for global warming potential (GWP100), 30.755 g oil-eq for fossil depletion potential (FDP), 38.974 mg P-eq for freshwater eutrophication potential (FEP), 8.907 μg CFC-11-eq for ozone depletion potential (ODP), 0.906 g NMVOC-eq for photochemical oxidant formation potential (POFP), and 1.029 g SO2-eq for terrestrial acidification potential (TAP). These results show a significant reduction, above −70%, for GWP100, FDP, and ODP compared with the same vehicle fueled on gasoline.

Life cycle assessment of waste management in rural areas in the transition period from mixed collection to source-separation

Rural solid waste management is essential for fulfilling sustainable development goals, especially in developing countries. However, quantitative study on this aspect has been little and far behind the urban areas. In this study, the environmental impacts of four typical rural solid waste management systems were quantified using life cycle assessment based on data from field investigations of five towns across four seasons. Sensitivity analysis was used to determine the most influential parameters. The results showed that landfilling mixed waste contributed the highest environmental impacts. By substituting landfilling with incineration, the environmental impacts (i.e., global warming potential, terrestrial acidification potential, fossil resource scarcity, freshwater ecotoxicity potential) dropped about 110%-900%. When shifting collection schemes to source separation, the environmental impacts also decreased by approximately 50%-200%. However, the environmental impacts of applying source separation to the existing management systems with mixed collection and disposal facilities of landfill or waste-to-energy (WTE) incineration are unclear and depend on the performance of decentralized composting and anaerobic digestion facilities, which need further investigations. Compared with urban cases, the landfill in rural areas emits higher greenhouse gas (GHG), and WTE incineration plants in rural areas have similar GHG emissions to WTE in urban areas. Besides, energy recovery was the most influential process in WTE systems and a 1% improvement on that would bring over 10% progress on global warming potential impact category. These findings can be useful for improving and developing rural domestic waste treatment in China and other developing countries.

Effects of feed formula and farming system on the environmental performance of shrimp production chain from a life cycle perspective

AbstractShrimp is the most popular seafood in the United States; its production plays an important role in the aquaculture industry. However, shrimp farming causes various environment impacts that must be mitigated to ensure the sustainability of shrimp production. This study performed a life cycle assessment (LCA) on two US‐based and one Vietnam‐based shrimp production chains from cradle to US market covering three farming systems and eight shrimp feed formulae. Midpoint environmental impacts including terrestrial acidification, freshwater eutrophication, and global warming were determined. For the intensive production chain (IPC), feed production was identified as the main contributor to the terrestrial acidification potential (TAP) and global warming potential (GWP), and its freshwater eutrophication potential (FEP) was dominated by shrimp farming. Poultry by‐product and fish meals were the feed ingredients contributing high TAP and GWP. However, soybean, wheat, and corn gluten meals produced higher FEP; hence, substituting plant‐based proteins for animal‐based ones in shrimp feeds did not all have positive environmental consequences. Shrimp farming was the hotspot of all the environmental impacts of the semi‐intensive production chain (SPC) and extensive production chain (EPC), except for the TAP of the EPC. Among the three production chains, the IPC had the highest FEP due to the on‐farm discharge of phosphorus‐containing wastewater, and the SPC caused the highest TAP because of the intensive uses of electricity and fertilizers for pond cultivation. Although the EPC was most sustainable in terms of TAP and FEP, open farming in mangrove areas produced the highest GWP owing to land transformation. This LCA study is expected to serve as US shrimp farmers’ decision‐making guidelines to adapt farming practices with lower environmental footprint.

Economic and environmental life cycle perspectives on two engineered wood products: comparison of LVL and GLT construction materials.

The embodied carbon of building materials and the energy consumed during construction have a significant impact on the environmental credentials of buildings. The structural systems of a building present opportunities to reduce environmental emissions and energy. In this regard, mass timber materials have considerable potential as sustainable materials over other alternatives such as steel and concrete. The aim of this investigation was to compare the environment impact, energy consumption, and life cycle cost (LCC) of different wood-based materials in identical single-story residential buildings. The materials compared are laminated veneer lumber (LVL) and glued laminated timber (GLT). GLT has less global warming potential (GWP), ozone layer depletion (OLD), and land use (LU), respectively, by 29%, 37%, and 35% than LVL. Conversely, LVL generally has lower terrestrial acidification potential (TAP), human toxicity potential (HTP), and fossil depletion potential (FDP), respectively, by 30%, 17%, and 27%. The comparative outcomes revealed that using LVL reduces embodied energy by 41%. To identify which of these materials is the best alternative, various environmental categories, embodied energy, and cost criteria require further analysis. Therefore, the multi-criteria decision-making (MCDM) method has been applied to enable robust decision-making. The outcome showed that LVL manufacturing using softwood presents the most sustainable choice. These research findings contribute to the body of knowledge about the use of mass timber in construction.

Global warming potential-based life cycle assessment and optimization of the compressive strength of fly ash-silica fume concrete; environmental impact consideration

In this research study, extensive literature searches on the compressive strength of concrete produced from the addition of fly ash (FA) and silica fume (SF) as extra constituents to the conventional concrete mixes, which gave rise to 330 mix points of concrete database. Due to the worrisome environmental impact of concrete production and usage in concrete activities, it has been pertinent to conduct the life cycle impact assessment of this procedure. Secondly, due to the over dependence of concrete production experts on laboratory exercise, there is also an urgent need to propose equations that reduce this dependence, that can be used in design, construction and performance evaluation of concrete infrastructure, hence the multi-objective nature of this research work. The results of the global warming potential (GWP) based on cement dosage show that Portland cement contributes about 90% of the total score. This is followed by the use of coarse aggregate contributing 6%, superplasticizer, 3% and fine aggregates, 2%. These show the functions of CO2 emissions and other greenhouses gas emissions in the entire system. Also, the result of the terrestrial acidification potential (TAP) for the concrete mixes in this study show that the lowest cement mix “C340-FAg658-FA0-SF15ˮ has a human toxicity, both carcinogenic and non-carcinogenic that showed an added impact of about 14 kg of 1, 4 equivalents of dichlorobenzene (DCB eq.). This result is 428% less impact than other studies found in the literature that used FA. Finally, it was found that the addition of FA and SF in concrete has a lowering effect on the environmental impact indicators due to reduced cement dosage. Furthermore, the results of the model predictions show that ANN with a performance index of 0.986 (4.8%) showed decisive superiority to predict the compressive strength of the FA-SF concrete over EPR, 0.951 (8.7%), GP, 0.94 (9.5%) and GEP, 0.93 (10%).

Analyzing the water-energy-environment nexus of irrigated wheat and maize production in Albania

This paper analyzed the water-energy-environmental interactions in conventional wheat and maize production on a generic farm in Albania using a cradle-to-farm gate life cycle assessment (LCA) and energy analysis. The inputs considered were seeds, fuel, electricity, fertilizers, plant protection, irrigation water, and machinery. Energy use efficiency, specific energy, energy productivity, and net energy gain in wheat production were calculated as 4.95, 2.63 MJ kg−1, 0.38 kg MJ −1, and 49,692 MJ ha−1, respectively. For maize, these values were 7.63, 1.93 MJ kg−1, 0.52 MJ kg−1, and 82,513 MJ ha−1, respectively. Producing 1 ton of wheat requires 2626 MJ of energy, 288 m3 of water, and generates a global warming potential (GWP) of 242.2 kg CO2-eq, terrestrial acidification potential (TAP) of 4.05 kg SO2-eq, and freshwater eutrophication (FEP) of 0.135 kg P-eq. On other hand, maize requires 1927.1 MJ of energy, 561 m3 of water, and generates a GWP of 181.1 kg CO2-eq, TAP of 2.82 kg SO2-eq, and FEP of 0.1 kg P-eq. The wheat and maize production produces a single environmental score of 69.3 and 60.2 points where the foreground subsystem (on-farm) contributes to more than 75% of the total environmental load. Irrigation, machinery use, and fertilizer use and application caused most of the environmental impacts and energy consumption. As a wide range of agriculture modernization projects is taking place across Albania, footprint indicators and energy analysis are recommended to design sound farming and irrigation practices and explore synergies and trade-offs of agricultural intensification.

Rice-crayfish coculture delivers more nutrition at a lower environmental cost

A growing demand for food products from limited arable land has meant that paddy fields have been developed to provide both grain and aquatic products. China has the world's largest aquaculture area of crayfish, of which ∼86% is in the form of rice-crayfish coculture. Here, we use a life cycle assessment to evaluate and compare the environmental impacts of three farming systems: rice monoculture, crayfish monoculture, and rice-crayfish coculture. Two functional units were used: one hectare of land occupied, and one Nutrient Density Unit (NDU) – i.e., the combined nutrition delivered in rice and/or crayfish products. Rice-crayfish coculture has a larger environmental footprint than rice monoculture per hectare occupied across at least 7 of the 8 impact categories studied, though performs better than crayfish monoculture. However, rice-crayfish coculture yields 1.12 to 2.21 times more nutrition per hectare than rice monoculture and crayfish monoculture, respectively. Hence, rice-crayfish coculture was found to have lower impact per NDU across all 8 impact categories studied, compared with the monoculture systems. Application of urea, crayfish feed inputs, and electricity consumption dominated most environmental burdens for rice-crayfish coculture, while field emissions (e.g., CH 4 and NH 3 ) strongly influenced global warming potential, terrestrial acidification potential and freshwater eutrophication potential, respectively. Environmental burdens of rice-crayfish coculture could be further reduced by increasing productivity per hectare and/or improving fertilizer and feed use efficiency. Shifting from rice- and crayfish-monoculture to rice-crayfish coculture could deliver more nutrition at a lower environmental cost, as well as increasing farm profitability by 7−462%.

Life cycle assessment of plant cell cultures

A novel food such as plant cell culture (PCC) is an important complementary asset for traditional agriculture to tackle global food insecurity. To evaluate environmental impacts of PCC, a life cycle assessment was applied to tobacco bright yellow-2 and cloudberry PCCs. Global warming potential (GWP), freshwater eutrophication potential (FEUP), marine eutrophication potential, terrestrial acidification potential (TAP), stratospheric ozone depletion, water consumption and land use were assessed. The results showed particularly high contributions (82–93%) of electricity consumption to GWP, FEUP and TAP. Sensitivity analysis indicated that using wind energy instead of the average Finnish electricity mix reduced the environmental impacts by 34–81%. Enhancement in the energy efficiency of bioreactor mixing processes and reduction in cultivation time also effectively improved the environmental performance (4–47% reduction of impacts). In comparison with other novel foods, the environmental impacts of the PCC products studied were mostly comparable to those of microalgae products but higher than those of microbial protein products produced by autotrophic hydrogen-oxidizing bacteria. Assayed fresh PCC products were similar or close to GWP of conventionally grown food products and, with technological advancements, can be highly competitive.

Environmental life cycle assessment of yellow mealworm (Tenebrio molitor) production for human consumption in Austria \u2013 a comparison of mealworm and broiler as protein source

PurposeGlobal food production needs to increase to provide enough food for over 9 billion people living by 2050. Traditional animal production is among the leading causes for climate change and occupation of land. Edible insects might be a sustainable protein supply to humans, but environmental life cycle assessment (LCA) studies on them are scarce. This study performs an LCA of a small-scale production system of yellow mealworms (Tenebrio molitor) in Central Europe that are supplied with organic feedstuff.MethodsA combined ReCiPe midpoint (H) and CED method is used to estimate the potential environmental impacts from cradle-to-gate. Impact categories include global warming potential (GWP), non-renewable energy use (NREU), agricultural land occupation (ALOP), terrestrial acidification potential (TAP) and freshwater eutrophication potential (FEP). The robustness of the results is tested via sensitivity analyses and Monte Carlo simulations.Results and discussionImpacts related to the production of 1 kg of edible mealworm protein amount to 20.4 kg CO2-eq (GWP), 213.66 MJ-eq (NREU), 22.38 m2 (ALOP), 159.52 g SO2-eq (TAP) and 12.41 g P-eq (FEP). Upstream feed production and on-farm energy demand related to the heating of the facilities are identified as environmental hot-spots: Depending on the impact category, feed supply contributes up to 90% and on-farm heating accounts for up to 65% of overall impacts. The organic mealworm production system is contrasted with a selected Austrian organic broiler production system, to which it compares favourably (18–72% lower impacts per category), with the exception of freshwater eutrophication (6% higher impacts).ConclusionsThis case study shows that the Austrian mealworm production system compares favourably to traditional livestock systems. Compared to LCAs from large-scale T. molitor rearing facilities in France and in the Netherlands, however, the Austrian production system cannot compete for the reasons of production scale, feed conversion efficiency and type of production system. Nevertheless, the investigated mealworms represent a sustainable protein alternative that should be added to the Western diet.

Life cycle assessment of a novel biomass-based aerogel material for building insulation

There is a growing interest in accounting for the environmental externalities and the greenhouse gas (GHG) emissions associated with the building industry. This study examines the life cycle environmental impacts of a novel biomass-based aerogel building material manufactured via freeze drying method comprising of three process stages, i.e., gel preparation, aging and freeze drying. The main focus of this study is to evaluate the contribution of each stage to the environmental load using life cycle assessment tool, figure out the main stage that has the greatest impact on the environment and propose some potential improvements by critical analysis of the production process. Life cycle impact scores are quantified as per functional unit of 1 m3 biomass-based aerogel for six midpoint impact categories (climate change potential, non-renewable energy potential, stratospheric ozone depletion, terrestrial acidification potential, terrestrial ecotoxicity and aquatic ecotoxicity). The respective LCA scores for these categories are depicted as 6.76E+02 kg CO2 eq., 1.65E+04 MJ, 4.21E-04 kg CFC-11 eq., 8.57E+00 kg SO2 eq., 2.07E+03 kg TEG soil and 9.87E+03 kg TEG. While comparing individual process substages, the freeze drying stage of the manufacturing process presents the highest overall impact contribution. Comparative environmental scoring with other aerogel types further reveals that the biomass-based aerogels are environmentally promising alternatives. Since the production is done at a laboratory scale, these results can be regarded as a conservative estimate, however they can act as steppingstones for process optimization for commercial scale manufacturing.

Life Cycle Assessment for Full Chain CCU Demonstration in the Align-CCUS Project –Dimethyl Ether and Polyoxymethylen Dimethyl Ethers Production from CO2 and its Usages in the Mobility and Electricity Sectors

As part of three years of research and development in the European ALIGN-CCUS project, a CCU demonstration plant was erected at the lignite-fired block K of the RWE power plant at Niederaussem, Germany. It was the aim to demonstrate the full chain of CCU - beginning with the capture of CO2 from the power plant flue gas stream, via the one-step synthesis of dimethyl ether (DME) through to its usage for electricity generation in a peak power diesel engine generator. A secondary target was the synthesis of polyoxymethylen dimethyl ethers (OMEs) and their use in the mobility sector. A thorough Life Cycle Inventory was collected based on real process data for the first time, supported by process modelling with AspenPlus. This includes the inventory for construction and operation of all elements of the demonstrator chain: the power plant with its monoethanolamine (MEA)-based post-combustion capture facility, the newly developed synthesis unit based on a one-step reactor using a bifunctional catalyst (up to 50 kg DME per day) and the reconversion of the produced DME into electricity by an adapted diesel power generator (60-80 litre per hour DME consumption, output 240 kWel). Additionally to the DME-route, the synthesis and usage of OME3-5 as a fuel in an adapted 2 l diesel motor for mobility application were part of the investigation. The extensive inventory enabled a Life Cycle Assessment (LCA) according to ISO standards showing results for both applications. Benchmarking technologies like diesel- and e-mobility and gas turbines for peak power supply enable a comparative analysis identifying advantages and disadvantages of the CCU route. A sensitivity analysis is used to identify weak points along the routes together with future development targets and potentials. To investigate a broad array of results, several varying scenarios, especially regarding energy supply were considered. The use of renewable electricity sources for electrolytic hydrogen production, but also for other processes of the CCU chain was investigated. A range of different impact categories were considered: Global Warming Potential (GWP), Particulate Matter Formation Potential (PM), Fossil Depletion Potential (FDP), Photochemical Ozone Creation Potential (POCP) and Terrestrial Acidification Potential (AP). The results show that the investigated CCU technology routes are highly emission-intensive when using the current German electricity mix: the reuse of CO2 and the reduction of fossil fuel consumption that goes along with it, is outweighed by the energy-intensive nature of the synthesis processes. Using renewable energy sources can drastically reduce GHG emissions, especially to a point where the implementation of a mostly renewable energy supply for the process chain offers a viable mitigation option compared to the investigated benchmark technologies. Findings regarding sensitive LCI data, development targets and technological potentials are discussed in the results.

Life cycle assessment of a biogas system for cassava processing in Brazil to close the loop in the water-waste-energy-food nexus

Biogas, generated from anaerobic digester (AD), has been one of the promising sources of renewable energy. To manage the organic waste from small cassava industry in Brazil, a waste-water-energy-food nexus (WWEF) system is proposed, combining AD and co-generation or combined heat and power (CHP) plants. However, the environmental impacts and benefits of this system are yet not known. By using Life Cycle Assessment (LCA) method, environmental impacts of three scenarios are assessed, i.e. business-as-usual (base), improved business-as-usual and WWEF closed-loop. Functional unit (FU) in this study is defined as generating 1 kg cassava starch/flour. Global warming potential (GWP), cumulative energy demand (CED), freshwater eutrophication potential (FEP), terrestrial acidification potential (TAP) and water depletion potential (WDP) are selected. Landfilling cassava waste, power use for cassava starch and flour production, and emissions from fertilizer application are identified as environmental hotspots for business-as-usual case, suggesting making decisions on these aspects when dealing with environmental impacts. By using cassava waste to recover energy and nutrients for Brazilian rural family farming, the WWEF system is identified as the best environment-friendly scenario with lowest environmental impacts for the selected impact categories. The impact savings of the closed-loop scenario for GWP are over 90%, while over 50% of emissions for other selected impact categories, except FEP (lower than 10%), are saved compared to the business-as-usual and improved scenarios. Sensitivity analysis reinforces the results. Overall, this study provides a view on the potential of using cassava waste for the WWEF closed-loop system in Brazil, suggesting that the proposed WWEF closed-loop system is feasible and beneficial for small industries from the environmental perspective.

Economic and environmental assessments of combined genetics and nutrition optimization strategies to improve the efficiency of sustainable pork production.

We evaluated the economic and environmental impacts of strategies that incorporated selection for pig feed efficiency and dietary optimization based on a single or multiple objectives tailored to meet the population nutritional requirements, with the goal to optimize sustainable farm feed efficiency. The economic and environmental features of the strategy were evaluated using life cycle assessment (LCA) and bio-economic models. An individual trait-based LCA model was applied to evaluate global warming potential, terrestrial acidification potential, freshwater eutrophication potential (EP), and land occupation of the combined genetics and nutrition optimization to produce 1 kg of live pig weighing 120 kg at the farm gate. A parametric individual trait-based bio-economic model was developed and applied to determine the cost breakdown, revenue, and profit to be gained from a 120-kg live pig at the farm gate. Data from two genetic lines with contrasted levels of feed efficiency were used to apply the combined genetics and nutrition optimization: accounting for the average nutritional requirements for each line, the individual pig responses to diets formulated for least cost, least environmental impacts, or minimum combination of costs and environmental impacts objectives were predicted with INRAPorc. Significant differences in the environmental impacts (P < 0.0001) and profit (P < 0.05) between lines predicted with the same reference diet showed that selection for feed efficiency (residual feed intake) in pigs improves pig production sustainability. When pig responses were simulated with their line-optimized diets, except for EP, all the line environmental impacts were lower (P < 0.05) than with the reference diet. The high correlations of feed conversion ratio with the environmental impacts (> 0.82) and the profit (< −0.88) in both lines underlined the importance of feed efficiency as a lever for the sustainability of pig production systems. Implementing combined genetics and nutrition optimization, the inherent profit and environmental differences between the genetic lines were predicted to be reduced from 23.4% with the reference diet to 7.6% with the diet optimized jointly for economic and environmental objectives (joint diet). Consequently, for increased pig sustainability, diet optimization for sustainability objectives should be applied to cover the specific nutritional requirements arising in the herd from the pigs genetic level.

Changes in the environmental impacts of pig production systems in Great Britain over the last 18 years

ContextThe aims of global pig production systems include a reduction of their environmental impacts, which can be achieved through an increase in outputs whilst minimising inputs. ObjectiveThe aim of this paper was to develop a novel method to enable estimation of the changes in the environmental impacts based on sparse data from the British pig production industry over ~20 years. MethodsTo achieve this, we developed a Life Cycle Assessment (LCA) method capable of dealing with sparse historical data from livestock systems. We applied it, for the first time, to estimate the temporal changes in environmental impacts of British pig production systems caused by changes in production performance. Performance data available from industry-held databases for indoor and outdoor bred pigs in Britain were used to estimate nutrient requirements through animal performance modelling, and feed composition through least-cost formulation. The cradle to farm-gate LCA model developed, included manure management and the full life cycle of the pigs and its functional unit was 1 kg of live weight pig at farm-gate. Sensitivity analyses were conducted to investigate the potential influence of changes in animal performance and feed prices on the estimated changes in environmental impacts. Results and ConclusionsThe higher growth rates and increased leanness over the period considered led to substantial reductions in energy requirements. Overall, the system changes led to reductions, for indoor and outdoor bred systems respectively, of 37.0% and 35.4% for Global Warming Potential, 21.2% and 16.4% in Terrestrial Acidification Potential, 22.5% and 22.3% in Freshwater Eutrophication Potential, 15.8% and 16.8% in Agricultural Land Use and 16.5% and 16.1% in Fossil Resource Scarcity. The sensitivity analyses showed that trends in feed composition were influential on the environmental impact outcomes, and that the LCA model was more sensitive to the change in feed composition than to the changes in animal performance over the time period considered. SignificanceKnowledge of temporal changes to the environmental impacts of livestock systems and the drivers of changes to date should guide future decisions to mitigate these impacts.

An approach to achieve overall farm feed efficiency in pig production: environmental evaluation through individual life cycle assessment

PurposeUse a holistic individual life cycle assessment (LCA) to investigate possible mitigation of environmental impacts through optimisation of overall farm feed efficiency by combining animal selection for feed efficiency and formulation of diets with minimum environmental impacts tailored to pig nutritional requirements.MethodsA linear multi-objective optimisation method was used to combine diet optimisation tailored to meet the representative nutritional requirements of genetic lines with environmental optimisation of the environmental impacts of the diet. Environmental optimisation was obtained by weighting the environmental impacts of the diet in a single environmental impact score. An individual trait-based LCA model with a cradle-to-farm-gate system boundary and functional unit of 1 kg live pig at the farm gate was applied to genetic lines selected for high (LRFI, high feed efficient line) and low (HRFI, low feed efficient line) feed efficiency data. The production traits of each individual animal in response to the optimised diets were simulated with InraPorc® and imported into the individual LCA model to assess global warming potential (GWP), terrestrial acidification potential (AP), freshwater eutrophication potential (EP), and land occupation (LO) of the overall farm feed efficiency approach.Results and discussionIntegrating selection for feed efficiency, nutritional requirements of genetic lines (HRFI and LRFI) and environmental diet optimisation resulted in overall mitigation of environmental impacts. Compared to the conventional diet, the environmental score of the optimised tailored diets was reduced by 5.8% and 5.2% for LRFI and HRFI lines, respectively. At the general production system level, the environmental impacts decreased by an average of 4.2% for LRFI and 3.8% for HRFI lines compared to environmental impacts of the lines fed the conventional diet (P < 0.05). The HRFI line with its optimised tailored diet had fewer impacts than the LRFI line with the conventional diet, except for EP. Individual LCA revealed high correlations between environmental impacts and feed efficiency and protein deposition traits.ConclusionsImplementation of overall farm feed efficiency would effectively mitigate environmental impacts. A holistic economic evaluation of the resulting trade-off between diet costs and pig performances is now needed to design a comprehensive tool to orientate selection and formulation decisions for sustainable pig production systems.

Life cycle inventory and impact assessment for an asphalt pavement road construction—a case study in Brazil

Currently, there are no life cycle impact data available on the construction of road infrastructure in Brazil. This study aimed to determine several environmental impacts associated with the construction of an asphalt-paved highway in Brazil using the life cycle assessment approach and road construction data available from two Brazilian highways. The results from this study can potentially raise awareness to the importance of life cycle thinking in road construction in Brazil. The processes considered within the asphalt road pavement product system were extraction and processing of sand, gravel, and pitch; transportation of these inputs; and machinery use and operation, including direct and indirect emissions, raw materials, and electricity/fuel. Inventories available in Ecoinvent were used, and processes relevant to the Brazilian scenario were selected, with modifications made when necessary. The ReCiPe method was used to calculate the impacts, and for each category a second method was used to verify the results. The impact categories analyzed were global warming potential (GWP), terrestrial acidification potential (TAP), ozone depletion potential (ODP), freshwater eutrophication (FWEP), marine eutrophication (MEP), and freshwater ecotoxicity (FWECP). In addition, an alternative scenario was considered by substituting diesel with biodiesel in the transportation trucks. Gravel production was the main contributor to TAP (56% based on ReCiPe) and MEP (62%) categories. It was also a significant contributor to the GWP (16%), FWEP (25%), and FWECP (33%) categories. Transport of raw materials was the most impactful process in the GWP (58%), FWEP (55%), and FWECP (52%) categories. Pitch production was the major contributor to the ODP category (57%). The impact from sand production was negligible for all categories. Machinery operation had a small contribution in all impact categories (less than 14%). The different assessment methods used for each category indicated similar percent contributions for all processes considered (gravel, sand, pitch, transport, and machinery). Substitution of diesel with biodiesel caused an increase in the total impact for all categories, except for ODP. Gravel and pitch production, as well as raw material transport, were the most impactful processes in road construction. Therefore, strategies to reduce the impacts of road construction projects should focus on these three processes. In particular, investigation of the environmental impact, using a life cycle approach, of substituting gravel and pitch with alternative or recycled materials should be carried out for the Brazilian context.

Life cycle assessment of electricity generation from combustion and gasification of biomass in Mexico

One measure to mitigate some of the nowadays environmental problems is the generation of products from renewable resources. In this context, this study's objective is to evaluate the environmental impacts associated with the use of sugarcane and agave bagasse from Mexico as a raw material for the generation of bioenergy, applying a life cycle assessment approach. Four scenarios were compared to determine the optimal feedstock (sugarcane or agave) and processing routes (combustion or gasification) from an environmental perspective. Life cycle assessment is performed according to the cradle-to-gate approach. In the case of the two-feedstocks studied, it was observed that the feedstock processing stage has high impact values in almost all impact categories. In this sense, it was observed that the combustion scenarios have high impact values in terms of ozone depletion potential (4.73 × 10−6 and 7.59 × 10−7 kg CFC11 eq), terrestrial acidification potential (1.41 × 10−2 and 7.82 × 10−3 kg SO2 eq), and fossil fuel potential (9.30 × 10−2 and 0.12 kg oil eq) for sugar extraction and bacanora production, respectively). For the gasification scenarios, the highest impact values ​​were observed for the terrestrial acidification potential (1.27 × 10−2 kg SO2 eq) and fossil fuel potential (8.41 × 10−2 kg oil eq) for sugar production and the ozone depletion potential (6.85 × 10−7 kg CFC11 eq), human toxicity potential - non-cancer (2.05 × 10−2 kg1,4-DCB) and fossil fuel potential (0.11kg oil eq) for bacanora production. Furthermore, it was observed that the sugarcane cultivation stage generates between 2 and 6 times more impact than the agave cultivation stage for almost all impact categories. Regarding the stages related to thermochemical processes, the impact values were relatively low, except for the following categories global warming potential, photochemical oxidation formation potential - humans, photochemical oxidation formation potential - ecosystems, terrestrial acidification potential, and water consumption potential, between 21 % and 88 % for the combustion process and between 32 % and 63 % for the gasification process. The main results of the comparisons between the four scenarios showed that the best scenario from an environmental perspective is agave bagasse combustion, followed by agave bagasse gasification, sugarcane bagasse gasification, and sugarcane bagasse combustion.