Energy requirements and environmental impacts associated with the production of short rotation willow (Salix sp.) chip in Ireland

Willow Salix sp. is currently cultivated as a short rotation forestry crop in Ireland as a source of biomass to contribute to renewable energy goals. The aim of this study is to evaluate the energy requirements and environmental impacts associated with willow (Salix sp.) cultivation, harvest, and transport using life cycle assessment (LCA). In this study, only emissions from the production of the willow chip are included, end‐use emissions from combustion are not considered. In this LCA study, three impact categories are considered; acidification potential, eutrophication potential and global warming potential. In addition, the cumulative energy demand and energy ratio of the system are evaluated. The results identify three key processes in the production chain which contribute most to all impact categories considered; maintenance, harvest and transportation of the crop. Sensitivity analysis on the type of fertilizers used, harvesting technologies and transport distances highlights the effects of these management techniques on overall system performance. Replacement of synthetic fertilizer with biosolids results in a reduction in overall energy demand, but raises acidification potential, eutrophication potential and global warming potential. Rod harvesting compares unfavourably in comparison with direct chip harvesting in each of the impact categories considered due to the additional chipping step required. The results show that dedicated truck transport is preferable to tractor‐trailer transport in terms of energy demand and environmental impacts. Finally, willow chip production compares favourably with coal provision in terms of energy ratio and global warming potential, while achieving a higher energy ratio than peat provision but also a higher global warming potential.     

Environmental burdens of producing bread wheat,oilseed rape and potatoes in England and Wales using simulation and system modelling

Background, aims and scope  

Food production is essential to life. Modern farming uses considerable resources to produce arable crops. Analysing the environmental burdens of alternative crop production methods is a vital tool for policymakers. The paper describes the production burdens (calculated by life cycle analysis) of three key arable crops: bread wheat, oilseed rape and potatoes as grown in England and Wales using organic and non-organic (contemporary conventional) systems. Resource use (e.g. abiotic and energy) and burdens from emissions are included (e.g. global warming potential on a 100-year basis, global warming potential (GWP), and eutrophication and acidification potentials).     

Rare Earths from Mines to Metals: Comparing Environmental Impacts from China's Main Production Pathways

Over the past decade, China has supplied over 90% of global rare earths, and in doing so bore significant environmental burdens from processing its complex ores. In this study, we used life cycle assessment to quantify environmental impacts for producing 1 kilogram (kg) of 15 rare earth elements from each major production pathway. The scope of assessment included the largest rare earth oxide (REO) production chain in Bayan Obo, as well as lesser known production chains for bastnäsite in Sichuan and in‐situ leaching of kaolin clays in the Seven Southern Provinces of China. This was followed by assessing impacts from the three major metal refining processes: molten salt electrolysis, calciothermic reduction, and lanthanothermic reduction. Among 11 impact categories assessed, results were highest for human toxicity that ranged between 13.1 and 50.4 kg 1,4‐dichlorobenzene‐eq (equivalent)/kg of rare earth metal^?1, followed by eutrophication (0.04 to 1.26 kg phosphate‐eq/kg of rare earth metal^?1), abiotic depletion potential of fossil fuels (592 to 1,857 megajoules per kg of rare earth metal^?1), acidification (0.25 to 0.87 kg sulfur dioxide‐eq/kg of rare earth metal^?1), and global warming (39.1 to 109.6 kg carbon dioxide‐eq/kg of rare earth metal^?1) potentials. Regionally, impacts in Sichuan were lower across all key impact categories than in Bayan Obo: 32% lower for human toxicity, 67% lower for eutrophication, 58% lower for acidification, and 45% lower for global warming. A scenario analysis between the industry average and best available technologies revealed considerable potential to mitigate impacts across all production chains, particularly by improving waste treatment practices.     

LCA of soybean meal

Background, Aim and Scope  Soybean meal is an important protein input to the European livestock production, with Argentina being an important supplier. The area cultivated with soybeans is still increasing globally, and so are the number of LCAs where the production of soybean meal forms part of the product chain. In recent years there has been increasing focus on how soybean production affects the environment. The purpose of the study was to estimate the environmental consequences of soybean meal consumption using a consequential LCA approach. The functional unit is ‘one kg of soybean meal produced in Argentina and delivered to Rotterdam Harbor’. Materials and Methods  Soybean meal has the co-product soybean oil. In this study, the consequential LCA method was applied, and co-product allocation was thereby avoided through system expansion. In this context, system expansion implies that the inputs and outputs are entirely ascribed to soybean meal, and the product system is subsequently expanded to include the avoided production of palm oil. Presently, the marginal vegetable oil on the world market is palm oil but, to be prepared for fluctuations in market demands, an alternative product system with rapeseed oil as the marginal vegetable oil has been established. EDIP97 (updated version 2.3) was used for LCIA and the following impact categories were included: Global warming, eutrophication, acidification, ozone depletion and photochemical smog. Results  Two soybean loops were established to demonstrate how an increased demand for soybean meal affects the palm oil and rapeseed oil production, respectively. The characterized results from LCA on soybean meal (with palm oil as marginal oil) were 721 gCO₂ eq. for global warming potential, 0.3 mg CFC11 eq. for ozone depletion potential, 3.1 g SO₂ eq. for acidification potential, −2 g NO₃ eq. for eutrophication potential and 0.4 g ethene eq. for photochemical smog potential per kg soybean meal. The average area per kg soybean meal consumed was 3.6 m²year. Attributional results, calculated by economic and mass allocation, are also presented. Normalised results show that the most dominating impact categories were: global warming, eutrophication and acidification. The ‘hot spot’ in relation to global warming, was ‘soybean cultivation’, dominated by N₂O emissions from degradation of crop residues (e.g., straw) and during biological nitrogen fixation. In relation to eutrophication and acidification, the transport of soybeans by truck is important, and sensitivity analyses showed that the acidification potential is very sensitive to the increased transport distance by truck. Discussion  The potential environmental impacts (except photochemical smog) were lower when using rapeseed oil as the marginal vegetable oil, because the avoided production of rapeseed contributes more negatively compared with the avoided production of palm oil. Identification of the marginal vegetable oil (palm oil or rapeseed oil) turned out to be important for the result, and this shows how crucial it is in consequential LCA to identify the right marginal product system (e.g., marginal vegetable oil). Conclusions  Consequential LCAs were successfully performed on soybean meal and LCA data on soybean meal are now available for consequential (or attributional) LCAs on livestock products. The study clearly shows that consequential LCAs are quite easy to handle, even though it has been necessary to include production of palm oil, rapeseed and spring barley, as these production systems are affected by the soybean oil co-product. Recommendations and Perspectives  We would appreciate it if the International Journal of Life Cycle Assessment had articles on the developments on, for example, marginal protein, marginal vegetable oil, marginal electricity (related to relevant markets), marginal heat, marginal cereals and, likewise, on metals and other basic commodities. This will not only facilitate the work with consequential LCAs, but will also increase the quality of LCAs.     

Life cycle assessment of primary magnesium production using the Pidgeon process in China

Background, aims, and scope  China has been the largest primary magnesium producer in the world since year 2000 and is an important part of the global magnesium supply chain. Almost all of the primary magnesium in China is produced using the Pidgeon process invented in the 1940s in Canada. The environmental problems of the primary magnesium production with the Pidgeon process have already attracted much attention of the local government and enterprises. The main purposes of this research are to investigate the environmental impacts of magnesium production and to determine the accumulative environmental performances of three different scenarios. System boundary included the cradle-to-gate life cycle of magnesium production, including dolomite ore extraction, ferrosilicon production, the Pidgeon process, transportation of materials, and emissions from thermal power plant. The life cycle assessment (LCA) case study was performed on three different fuel use scenarios from coal as the overall fuel to two kinds of gaseous fuels, the producer gas and coke oven gas. The burden use of gaseous fuels was also considered. Methods  The procedures, details, and results obtained are based on the application of the existing international standards of LCA, i.e., the ISO 14040. Depletion of abiotic resources, global warming, acidification, and human toxicity were adopted as the midpoint impact categories developed by the problem-oriented approach of CML to estimate the characterized results of the case study. The local characterization and normalization factors of abiotic resources were used to calculate abiotic depletion potential (ADP). The analytic hierarchy process was used to determine the weight factors. Using the Umberto version 4.0, the emissions of dolomite ore extraction were estimated and the transportation models of the three scenarios were designed. Results and conclusions  The emissions inventory showed that both the Pidgeon process of magnesium production and the Fe–Si production were mainly to blame for the total pollutant emissions in the life cycle of magnesium production. The characterized results indicated that ADP, acidification potential, and human toxicity potential decreased cumulatively from scenarios 1 to 3, with the exception of global warming potential. The final single scores indicated that the accumulative environmental performance of scenario 3 was the best compared with scenarios 1 and 2. The impact of abiotic resources depletion deserves more attention although the types and the amount of mineral resources for Mg production are abundant in China. This study suggested that producer gas was an alternative fuel for magnesium production rather than the coal burned directly in areas where the cost of oven gas-produced coke is high. The utilization of “clean” energy and the reduction of greenhouse gases and acidic gases emission were the main goals of the technological improvements and cleaner production of the magnesium industry in China. Recommendation and perspective  This paper has demonstrated that the theory and method of LCA are actually helpful for the research on the accumulative environmental performance of primary magnesium production. Further studies with “cradle-to-cradle” scheme are recommended. Furthermore, other energy sources used in magnesium production and the cost of energy production could be treated in further research.     

东北有机及常规大豆对环境影响的生命周期评价

选择我国主要有机出口农产品之一——大豆作为研究对象,采用生命周期评价、DNDC模型、实地调研等方法建立大豆生命周期资源消耗和环境排放清单,分析比较了出口型有机大豆、国内消费型有机大豆以及国内消费型常规大豆的生命周期环境影响.结果表明:3种不同生产消费型大豆生命周期中资源消耗、酸化以及全球变暖对综合环境影响贡献最明显,基本上占到综合环境影响评价的30％左右,而富营养化和生态毒性的贡献率较低,小于10％.从生命周期的不同阶段分析,3种消费模式的大豆其运输阶段对于各分类环境影响的贡献率最大,都在50％以上,对资源消耗的贡献率更是在80％以上.从2种不同的生产模式看无论是全球变暖、酸化、资源消耗还是生态毒性都是有机大豆的环境影响综合指数小于常规大豆,对环境产生的负面影响较小.综合比较3种不同生产消费型大豆,国内消费的有机大豆生命周期综合环境影响最小,其环境影响综合指数比常规大豆的减少31％.但是出口有机大豆由于出口使运输距离延长,其生命周期综合环境影响最大.因此,环境管理关键是提倡有机产品本地消费以缩短运输距离,或者采用环保型能源以减少环境排放.     

全球变化对海洋生态系统初级生产关键过程的影响

工业革命以来, 不断加剧的人类活动所引起的大气CO₂浓度增加、温度上升等全球变化问题, 正使得海洋生态系统面临着前所未有的压力。该文通过文献计量的方法分析了国内外的研究现状, 简要地回顾了全球变化对海洋生态系统影响研究的发展简史, 并聚焦海洋暖化、海洋酸化和富营养化与缺氧这三个核心研究方向, 重点阐述了它们对海洋生态系统初级生产的关键过程的影响, 总结了已取得的重要进展以及存在的主要问题, 最后提出前沿展望。     

Effects of global change on key processes of primary production in marine ecosystems

工业革命以来, 不断加剧的人类活动所引起的大气CO₂浓度增加、温度上升等全球变化问题, 正使得海洋生态系统面临着前所未有的压力。该文通过文献计量的方法分析了国内外的研究现状, 简要地回顾了全球变化对海洋生态系统影响研究的发展简史, 并聚焦海洋暖化、海洋酸化和富营养化与缺氧这三个核心研究方向, 重点阐述了它们对海洋生态系统初级生产的关键过程的影响, 总结了已取得的重要进展以及存在的主要问题, 最后提出前沿展望。     

Application of life cycle assessment to landfilling

A case study of a life-cycle assessment (LCA) is performed concerning the treatment of household solid wastes in a landfill. The stages considered in this LCA study are: goal and scope definition, inventory analysis and impact assessment. The data of the inventory include the consumption of raw materials and energy through the transport of wastes and the management of landfill, and the corresponding emissions to the environment. Abiotic resource depletion, global warming, acidification, eutrophication and human toxicological impacts have been considered as impact categories for the impact assessment phase of the LCA. A comparison of the environmental impact of the landfilling with and without energy recovery is carried out. Members of the Spanish Association for LCA Development (APRODACV)     

Impact Characterization in the Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts

The tool for the reduction and assessment of chemical and other environmental impacts (TRACI) is a set of life-cycle impact assessment (LCIA) characterization methods that has been developed by a series of U.S. Environmental Protection Agency research projects. TRACI facilitates the characterization of stressors that may have potential effects, including ozone depletion, global warming, acidification, eutrophication, tropospheric ozone (smog) formation, eco-toxicity, human particulate effects, human carcinogenic effects, human non-carcinogenic effects, fossil fuel depletion, and land-use effects. This article describes the methodologies developed to address acidification, eutrophication, and smog. Each of these methods offers the ability to take account of differences in expected strength of impact as a function of pollution release location within North America. Specifically, the methods employ regionalized fate and transport modeling. The resulting factors differ regionally by up to more than an order of magnitude.     

基于生命周期方法的生活垃圾资源化利用系统生态效率分析

我国生活垃圾产量大但处理能力不足,产生多种环境危害,对其资源化利用能够缓解环境压力并回收资源。为探讨生活垃圾资源化利用策略,综合生命周期评价与生命周期成本分析方法,建立生态效率模型。以天津市为例,分析和比较焚烧发电、卫生填埋-填埋气发电、与堆肥+卫生填埋3种典型生活垃圾资源化利用情景的生态效率。结果表明,堆肥+卫生填埋情景具有潜在最优生态效率;全球变暖对总环境影响贡献最大,而投资成本对经济影响贡献最大。考虑天津市生活垃圾管理现状,建议鼓励发展生活垃圾干湿组分分离及厨余垃圾堆肥的资源化利用策略。     

Prospective Life Cycle Assessment of Epitaxial Graphene Production at Different Manufacturing Scales and Maturity

Epitaxial growth is a potential production process for the new material graphene, where it is grown on silicon carbide (SiC) wafers at high temperatures. We provide first estimates of the life cycle cumulative energy demand, climate change, terrestrial acidification, and eco‐toxicity of this production. For this purpose, we applied prospective life cycle assessment (LCA) for three production scenarios (lab, pilot, and an industrial scenario), which reflect different production scales and technological maturity. The functional unit was one square centimeter of graphene. Results show that the three scenarios have similar impacts, which goes against previous studies that have suggested a decrease with larger production scale and technological maturity. The reason for this result is the dominance of electricity use in the SiC wafer production for all impacts (>99% in the worst case, >76% in the best case). Only when assuming thinner SiC wafers in the industrial scenario is there a reduction in impacts by around a factor of 10. A surface‐area–based comparison to the life cycle energy use of graphene produced by chemical vapor deposition showed that epitaxial graphene was considerably more energy intensive—approximately a factor of 1,000. We recommend producers of epitaxial graphene to investigate the feasibility of thinner SiC wafers and use electricity based on wind, solar, or hydropower. The main methodological recommendation from the study is to achieve a temporal robustness of LCA studies of emerging technologies, which includes the consideration of different background systems and differences in production scale and technological maturity.     

Evaluating environmental impacts of contrasting pig farming systems with life cycle assessment

Environmental impacts of 15 European pig farming systems were evaluated in the European Union Q-PorkChains project using life cycle assessment. One conventional and two non-conventional systems were evaluated from each of the five countries: Denmark, The Netherlands, Spain, France and Germany. The data needed for calculations were obtained from surveys of 5 to 10 farms from each system. The systems studied were categorised into conventional (C), adapted conventional (AC), traditional (T) and organic (O). Compared with C systems, AC systems differed little, with only minor changes to improve meat quality, animal welfare or environmental impacts, depending on the system. The difference was much larger for T systems, using very fat, slow-growing traditional breeds and generally outdoor raising of fattening pigs. Environmental impacts were calculated at the farm gate and expressed per kg of pig live weight and per ha of land used. For C systems, impacts per kg LW for climate change, acidification, eutrophication, energy use and land occupation were 2.3 kg CO₂-eq, 44.0 g SO₂-eq, 18.5 g PO₄-eq, 16.2 MJ and 4.1 m², respectively. Compared with C, differences in corresponding mean values were +13%, +5%, 0%, +2% and +16% higher for AC; +54%, +79%, +23%, +50% and +156% for T, and +4%, −16%, +29%, +11% and +121% for O. Conversely, when expressed per ha of land use, mean impacts were 10% to 60% lower for T and O systems, depending on the impact category. This was mainly because of higher land occupation per kg of pig produced, owing to feed production and the outdoor raising of sows and/or fattening pigs. The use of straw bedding tended to increase climate change impact per kg LW. The use of traditional local breeds, with reduced productivity and feed efficiency, resulted in higher impacts per kg LW for all impact categories. T systems with extensive outdoor raising of pigs resulted in markedly lower impact per ha of land used. Eutrophication potential per ha was substantially lower for O systems. Conventional systems had lower global impacts (global warming, energy use, land use), expressed per kg LW, whereas differentiated systems had lower local impacts (eutrophication, acidification), expressed per ha of land use.     

Life cycle assessment of printing and writing paper produced in Portugal

Goal, Scope and Background The environmental sustainability is one of the current priorities of the Portuguese pulp and paper industry. Life Cycle Assessment (LCA) was the methodology chosen to evaluate the sustainability of the printing and writing paper production activity. This paper grade represents about 60% of the total production of paper in Portugal and its production is expected to increase in the near future. The main goal of this study was to assess the potential environmental impacts associated with the entire life cycle of the printing and writing paper produced in Portugal from Eucalyptus globulus pulp and consumed in Germany, in order to identify the processes with the largest environmental impacts. Another goal of this study was to evaluate the effect on the potential environmental impacts of changing the market where the Portuguese printing and writing paper is consumed: German market vs. Portuguese market. Methods The main stages considered in this study were: forestry, pulp production, paper production, paper distribution, and paper final disposal. Transports and production of chemicals, fuels and energy in the grid were also included in these stages. Whenever possible and feasible, average or typical data from industry were collected. The remaining data were obtained from the literature and specialised databases. A quantitative impact assessment was performed for five impact categories: global warming over 100 years, acidification, eutrophication, non-renewable resource depletion and photochemical oxidant formation. Results In the German market scenario, the paper production stage was a remarkable hot spot for air emissions (non-renewable CO₂, NO_x and SO₂) and for non-renewable energy consumption, and, consequently, for the impact categories that consider these parameters: global warming, acidification and non-renewable resource depletion. These important environmental impacts are due to the energy requirements in the printing and writing paper production process, which are fulfilled by on-site fuel oil burning and consumption of electricity from the national grid, which is mostly based on the use of fossil fuels. The pulp production stage was identified as the largest contributor to water emissions (COD and AOX) and to eutrophication. Considering that energy consumed by the pulp production processes comes from renewable fuels, this stage was also the most contributing to renewable energy consumption. Discussion The paper distribution stage showed an important contribution to NO_x emissions, which, however, did not result in a major contribution to acidification or eutrophication. The final disposal stage was the main contributor to the photochemical oxidant formation potential due to CH₄ emissions from wastepaper landfilling. On the other hand, paper consumption in Portugal was environmentally more favourable than in Germany for the parameters/impact categories where the paper distribution stage has a significant contribution (non-renewable CO₂, NO_x, non-renewable energy consumption, acidification, eutrophication and non-renewable resource depletion) due to shorter distances needed to deliver paper to the consumers. For the remaining parameters/impact categories, the increase observed in the final disposal stage in the Portuguese market was preponderant, and resulted from the existence of significant differences in the final disposal alternatives in the analysed markets (recycling dominates in Germany, whereas landfilling dominates in Portugal). Conclusions The pulp and paper production stages were found to be of significance for almost all of the inventory parameters as well as for the impact assessment categories. The paper distribution and the final disposal stages were only of importance for some of the inventory parameters and some of the impact categories. The forestry stage played a minor role in the environmental impacts generated during the paper life cycle. The consumption of paper in Portugal led to a decrease in the environmental burdens of the paper distribution stage, but to an increase in the environmental burdens of the final disposal stage, when compared with the consumption of paper in Germany. Recommendations and Perspectives This study provides useful information that can assist the pulp and paper industry in the planning of future investments leading to an increase in its sustainability. The results of inventory analysis and impact assessment show the processes that play an important role in each impact category, which allow the industry to improve its environmental performance, making changes not only in the production process itself, but also in the treatment of flue gases and liquid effluents. Besides that concern regarding pollution prevention, other issues with relevance to the context of sustainability, such as the energy consumption, can also be dealt with.     

Life Cycle Assessment Study of Biopolymers (Polyhydroxyalkanoates) - Derived from No-Tilled Corn (11 pp)

Goal and Scope This study attempts to estimate the environmental performance of Polyhydroxyalkanoates (PHA), from agricultural production through the PHA fermentation and recovery process – “cradle to gate”. Two types of PHA production systems are investigated: corn grain based PHA and corn grain and corn stover based PHA. Methods Corn cultivation data are taken from 14 counties in the Corn Belt states of the United States – Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio, and Wisconsin. The environmental burdens associated with the corn wet milling process, in which dextrose, corn oil, corn gluten meal and corn gluten feed are produced, are allocated to dextrose and its coproducts by the system expansion approach. Greenhouse gases include carbon taken up by soil, nitrous oxide (N2O) released from soil during corn cultivation, carbon contents in biobased products as well as carbon dioxide, methane and nitrous oxide released from industrial processing. The soil carbon and nitrogen dynamics in corn cultivation are predicted by an agro–ecosystem model, the DAYCENT model. The environmental performance of the PHA production system is compared to that of a conventional polymer fulfilling an equivalent function. The environmental performance is addressed as nonrenewable energy and selected potential environmental impacts including global warming, photochemical smog, acidification, and eutrophication. The characterization factors are adapted from the TRACI model (Tools for the Reduction and Assessment of Chemical and Other Environmental Impacts) developed by the United States Environmental Protection Agency. Results and Discussion Global warming associated with corn grain based PHA is 1.6–4.1 kg-CO2 eq. kg–1. The primary contributing process to most environmental impacts except for photochemical smog and eutrophication is the PHA fermentation and recovery process. For photochemical smog and eutrophication, the primary contributing process is corn cultivation due to nitrogen related burdens from soil. The trend of PHA fermentation development shows that the PHA fermentation technology is still immature and continues to improve, thereby also decreasing the environmental impacts. PHA produced in an integrated system, in which corn stover is harvested and used as raw material for PHA along with corn grain, offers global warming credits (negative greenhouse gas emissions), ranging from –0.28 to –1.9 kg-CO2 eq. kg–1, depending on the PHA fermentation technologies employed and significantly reduces the environmental impacts compared to corn based PHA. The significant reductions from the integrated system are due to 1) less environmental impacts in corn cultivation and wet milling, and 2) exporting surplus energy from lignin–rich residues in corn stover process.Conclusions and Outlook Under the current PHA fermentation technology, corn grain based PHA does not provide an environmental advantage over polystyrene. Corn grain based PHA produced by the near future PHA fermentation technology would be more favorable than polystyrene in terms of nonrenewable energy and global warming due to improvement in the PHA fermentation and recovery process. However, corn grain based PHA produced in even the near future technology does not provide better profiles for other environmental impacts (i.e., photochemical smog, acidification and eutrophication) than polystyrene. One of the primary reasons for high impacts of PHA in photochemical smog, acidification and eutrophication is the environmental burdens associated with corn cultivation. Thus other approaches to reduce these burdens in the agricultural process (e.g., use of buffer strips, etc.) are necessary to achieve better profiles for photochemical smog, acidification and eutrophication associated with corn cultivation. PHA produced in the integrated system is more favorable than polystyrene in terms of most environmental impacts considered here except for eutrophication.     

Anaerobic digestion of starch-polyvinyl alcohol biopolymer packaging: biodegradability and environmental impact assessment

The digestibility of a starch-polyvinyl alcohol (PVOH) biopolymer insulated cardboard coolbox was investigated under a defined anaerobic digestion (AD) system with key parameters characterized. Laboratory results were combined with industrial operational data to develop a site-specific life cycle assessment (LCA) model. Inoculated with active bacterial trophic groups, the anaerobic biodegradability of three starch-PVOH biopolymers achieved 58-62%. The LCA modeling showed that the environmental burdens of the starch-PVOH biopolymer packaging under AD conditions on acidification, eutrophication, global warming and photochemical oxidation potential were dominated by atmospheric emissions released from substrate degradation and fuel combustion, whereas energy consumption and infrastructure requirements were the causes of abiotic depletion, ozone depletion and toxic impacts. Nevertheless, for this bio-packaging, AD of the starch-PVOH biopolymer combined with recycling of the cardboard emerged as the environmentally superior option and optimization of the energy utilization system could bring further environmental benefits to the AD process.     

Environmental assessment of yield improvements obtained by the use of the enzyme phospholipase in mozzarella cheese production

Background, aim and scope  Phospholipase is an enzyme which is able to increase the yield of cheese in, for instance, mozzarella production. Milk production is the most important source of environmental impacts in cheese production and it is obvious to assume that the milk saving that comes with the use of phospholipase reduces the overall environmental impacts of the final product. Production of industrial phospholipase is, however, also associated with environmental burdens and it is not known whether and to what extent the use of phospholipase is justified by overall environmental improvements. The aim of the present study is therefore to assess the environmental impacts that come with the use of industrial phospholipase in mozzarella production and compare with the savings that come with the avoided milk production. The study addresses mozzarella production in Denmark. Methods  LCA is used as analytical tool and environmental modelling is facilitated in SimaPro 7.1.8 LCA software. Yield improvements refer to full scale industrial application of phospholipase in cheese industry. The study is a comparative analysis and a marginal and market-oriented approach is taken. The study addresses contribution to global warming, acidification, nutrient enrichment, photochemical smog formation, energy consumption and use of agricultural land. Estimation of environmental impact potentials is based on Eco-indicator 95 v.2.1 equivalency factors. Toxicity is addressed by qualitative means. Results  The environmental impacts induced by phospholipase production are small compared with the savings obtained by reduced milk consumption for mozzarella production when all impact indicators are considered. Sensitivity analyses and data quality assessments indicate that this general outcome of the study is robust, although results at the more detailed level are the subject of much variation and uncertainty. Discussion  Transport of the enzyme from producer to mozzarella producer is insignificant and the general outcome of the study is considered applicable to other regions of the world where milk is produced in modern milk production systems. Conclusions  Use of phospholipase as a yield improvement factor is a means of reducing environmental impact of mozzarella production. Recommendations and perspectives  The total annual global warming mitigation potential of phospholipase used in production of mozzarella and other pasta filata products is in the order of 7 × 10⁸ kg CO₂ equivalents. The use of phospholipase is driven by overall cost savings and it is therefore recommended that the enzyme should be given attention as a cost-efficient means of reducing greenhouse gas emissions.     

Decline in growth of foraminifer Marginopora rossi under eutrophication and ocean acidification scenarios

The combination of global and local stressors is leading to a decline in coral reef health globally. In the case of eutrophication, increased concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) are largely attributed to local land use changes. From the global perspective, increased atmospheric CO₂ levels are not only contributing to global warming but also ocean acidification (OA). Both eutrophication and OA have serious implications for calcium carbonate production and dissolution among calcifying organisms. In particular, benthic foraminifera precipitate the most soluble form of mineral calcium carbonate (high‐Mg calcite), potentially making them more sensitive to dissolution. In this study, a manipulative orthogonal two‐factor experiment was conducted to test the effects of dissolved inorganic nutrients and OA on the growth, respiration and photophysiology of the large photosymbiont‐bearing benthic foraminifer, Marginopora rossi. This study found the growth rate of M. rossi was inhibited by the interaction of eutrophication and acidification. The relationship between M. rossi and its photosymbionts became destabilized due to the photosymbiont's release from nutrient limitation in the nitrate‐enriched treatment, as shown by an increase in zooxanthellae cells per host surface area. Foraminifers from the OA treatments had an increased amount of Chl a per cell, suggesting a greater potential to harvest light energy, however, there was no net benefit to the foraminifer growth. Overall, this study demonstrates that the impacts of OA and eutrophication are dose dependent and interactive. This research indicates an OA threshold at pH 7.6, alone or in combination with eutrophication, will lead to a decline in M. rossi calcification. The decline in foraminifera calcification associated with pollution and OA will have broad ecological implications across their ubiquitous range and suggests that without mitigation it could have serious implications for the future of coral reefs.     

Environmental assessment of energy production from municipal solid waste incineration

Background, Aims and Scope During the combustion of municipal solid waste (MSW), energy is produced which can be utilized to generate electricity. However, electricity production from incineration has to be evaluated from the point view of the environmental performance. In this study, environmental impacts of electricity production from waste incineration plant in Thailand are compared with those from Thai conventional power plants. Methods The evaluation is based on a life cycle perspective using life cycle assessment (LCA) as the evaluation tool. Since MSW incineration provides two services, viz., waste management and electricity production, the conventional power production system is expanded to include landfilling without energy recovery, which is the most commonly used waste management system in Thailand, to provide the equivalent function of waste management. Results The study shows that the incineration performs better than conventional power plants vis-à-vis global warming and photochemical ozone formation, but not for acidification and nutrient enrichment. Discussion There are some aspects which may influence this result. If landfilling with gas collection and flaring systems is included in the analysis along with conventional power production instead of landfilling without energy recovery, the expanded system could become more favorable than the incineration in the global warming point of view. In addition, if the installation of deNO_x process is employed in the MSW incineration process, nitrogen dioxide can be reduced with a consequent reduction of acidification and nutrient enrichment potentials. However, the conventional power plants still have lower acidification and nutrient enrichment potentials. Conclusions The study shows that incineration could not play the major role for electricity production, but in addition to being a waste management option, could be considered as a complement to conventional power production. To promote incineration as a benign waste management option, appropriate deNO_x and dioxin removal processes should be provided. Separation of high moisture content waste fractions from the waste to be incinerated and improvement of the operation efficiency of the incineration plant must be considered to improve the environmental performance of MSW incineration. Recommendations This study provides an overall picture and impacts, and hence, can support a decision-making process for implementation of MSW incineration. The results obtained in this study could provide valuable information to implement incineration. But it should be noted that the results show the characteristics only from some viewpoints. Outlook Further analysis is required to evaluate the electricity production of the incineration plant from other environmental aspects such as toxicity and land-use.