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Food waste has a high energy potential that can be converted into useful energy in the form of methane via anaerobic digestion. Biochemical Methane Potential assays (BMPs) were conducted to quantify the impacts on methane production of different ratios of food waste. Anaerobic digester sludge (ADS) was used as the inoculum, and BMPs were performed at food waste:inoculum ratios of 0.42, 1.42, and 3.0 g chemical oxygen demand/g volatile solids (VS). The 1.42 ratio had the highest CH 4 -COD recovery: 90% of the initial total chemical oxygen demand (TCOD) was from food waste, followed by ratios 0.42 and 3.0 at 69% and 57%, respectively. Addition of food waste above 0.42 caused a lag time for CH 4 production that increased with higher ratios, which highlighted the negative impacts of overloading with food waste. The Gompertz equation was able to represent the results well, and it gave lag times of 0, 3.6 and 30 days and maximum methane productions of 370, 910, and 1950 mL for ratios 0.42, 1.42 and 3.0, respectively. While ratio 3.0 endured a long lag phase and low VSS destruction, ratio 1.42 achieved satisfactory results for all performance criteria. These results provide practical guidance on food-waste-to-inoculum ratios that can lead to optimizing methanogenic yield. [ABSTRACT FROM AUTHOR]

The United States has 121 million ha of marginal land that could be used to produce renewable energy. Approximately 1.73 million ha of this land includes federally funded brownfields, closed landfills, and abandoned mine lands. This study presents a GIS model to evaluate a range of site-specific energy production potentials on brownfields, closed landfills, and abandoned mine lands. Five energy sources are considered: soybeans, sunflowers, and algae for biodiesel, and solar and wind for electricity. Using soybeans, sunflowers, and algae, the United States could produce 39.9×10 3 TJ–59.1×10 3 TJ of renewable fuel per year from biodiesel. Using solar and wind resources, the United States could produce 114–53 TW h per year of electricity. The lower end of the range for each resource represents marginal yields as expected under marginal conditions. The upper end of the range represents prime conditions and is used for comparison to other, more productive types of land and U.S. regional climates. While renewable energy sources sited on individual sites may produce marginal amounts of energy, strategic uses of land and combinations of sources can supplement the national energy matrix. The five renewable energy sources examined in this study could meet up to 39% of the total U.S. 2013 energy demand for biofuel and electricity. [ABSTRACT FROM AUTHOR]

Cultured, or in vitro, meat consists of edible biomass grown from animal stem cells in a factory, or carnery. In the coming decades, in vitro biomass cultivation could enable the production of meat without the need to raise livestock. Using an anticipatory life cycle analysis framework, the study described herein examines the environmental implications of this emerging technology and compares the results with published impacts of beef, pork, poultry, and another speculative analysis of cultured biomass. While uncertainty ranges are large, the findings suggest that in vitro biomass cultivation could require smaller quantities of agricultural inputs and land than livestock; however, those benefits could come at the expense of more intensive energy use as biological functions such as digestion and nutrient circulation are replaced by industrial equivalents. From this perspective, large-scale cultivation of in vitro meat and other bioengineered products could represent a new phase of industrialization with inherently complex and challenging trade-offs. [ABSTRACT FROM AUTHOR]

Life cycle assessment (LCA) is a quantitative tool used to evaluate the environmental impacts of products or processes. With respect to buildings, LCA can be used to evaluate the environmental impacts of an entire building's life cycle. Currently LCA in the building area is used in a limited capacity, primarily to select building products. In order to determine the causality for the lack of whole-building LCAs, focus groups with members of the architecture, engineering, and construction (AEC) communities were held. This article investigates the current level of knowledge of LCA in the AEC community and then discusses the benefits and barriers to the practice of LCA. In summary, the goal of the research was to identify why LCA is not used to its fullest potential in a whole-building LCA. In an open forum and moderated setting, focus group participants were asked individually to self-identify their experience with LCA, a brief education session on LCA was held, and then benefits and barriers to LCA were discussed. The focus group sessions were transcribed and systematically coded by social researchers in order to analyze the results. Hybrid flow and radar charts were developed. From the focus group results, the most important benefit to LCA was 'provides information about environmental impacts.' The results did not identify a prominent barrier; however, building-related metrics were ascertained to be one of the more crucial barriers. The benefits and barriers classified by this analysis will be utilized to develop a subsequent online survey to further understand the LCA and AEC community. [ABSTRACT FROM AUTHOR]

Abstract: A comparative life cycle assessment (LCA) was conducted on 20 scenarios of microalgae cultivation. These scenarios examined the utilization of nutrients and CO2 from synthetic sources and waste streams as well as the materials used to construct a photobioreactor (PBR). A 0.2-m3 closed PBR of Chlorella vulgaris at 30%-oil content by weight with the productivity of 25g/m2 ×day was used as a case study. Results of the study show that the utilization of resources from waste streams mainly avoided global warming potential (GWP) and eutrophication impacts. Impacts from the production of material used to construct the PBR dominate total impacts in acidification and ozone depletion categories, even over longer PBR lifetimes; thus, the choice of PBR construction materials is important. [Copyright &y& Elsevier]

Abstract: As the demand for renewable energy increases, it becomes important to critically examine the environmental impacts of renewable energy production. Often, the approach has been trial and error in renewable energy with respect to its impact on the environment. Hydrokinetic Energy Extraction (HEE) has been seen as a potentially “benign” form of renewable hydropower. This paper provides a benchmark for initial measurement of HEE environmental impacts, since negative outcomes have been present with previously assumed “benign” renewable hydropower. A Gorlov system was used to represent a HEE system. Life Cycle Assessment (LCA) was utilized to compare the environmental impacts of HEE with small hydropower, coal, natural gas and nuclear power. Environmental Protection Agency (EPA) criteria air emissions were quantified and compared over the life cycle of the systems. Life cycle air emissions were used in combination with TRACI to compare the systems. The Gorlov system was found to have the lowest life cycle impact with a system lifetime comparison, and did compare closely with small hydropower. [Copyright &y& Elsevier]

Although the environmental impacts and carbon footprints of foods are gaining more public attention and scientific debate, few studies have systematically evaluated the life cycle nitrogen and phosphorus flows among different food types. Disruption of natural nitrogen and phosphorus cycles already result in serious environmental quality degradation and economic losses, such as loss of fisheries due to hypoxia in the Gulf of Mexico. This study characterizes the nutrient flows during food production, processing, packaging, and distribution stages for eight food types; compares carbon footprints and nitrogen equivalent footprints of food groups; evaluates solutions to reduce excessive nitrogen outputs; and estimates effectiveness and efficiency of possible solutions. Different food groups exhibit a highly variable nitrogen-intensity; on average, red meat and dairy products require much more nitrogen than cereals/carbohydrates. The ranking of foods' nitrogen footprints is not consistent with their carbon footprints. For example, dairy products and chicken/eggs have relatively high nitrogen footprint and low carbon footprints. Finally, the study evaluates shifting food consumption patterns. Dietary shifts from dairy products and red meat to cereals can be an effective approach for lowering the personal nitrogen footprint. [ABSTRACT FROM AUTHOR]

The article examines the trade-offs of carbon and nitrogen cycles related to agriculture. After being absorbed by plants during photosynthesis, carbon is released through either combustion or biological processes. Reactive nitrogen is released throughout the life cycle of a bioproduct which causes an increase in the aggregate nitrogen flux. Carbon released at the end of a bioproduct's life is obtained from the atmosphere via photosynthesis and can be recycled to create additional biomass. The use of bioproducts helps to mitigate climate changes. The carbon and nitrogen cycles in agriculture are interconnected. INSET: Unintended consequences.

A comparative life cycle assessment examining soybean and petroleum-based lubricants is compiled using Monte Carlo analysis to assess system variability. Experimental data obtained from an aluminum manufacturing facility indicate significantly less soybean lubricant is required to achieve similar or superior performance. With improved performance and a lower use rate, a transition to soybean oil results in lower aggregate impacts of acidification, smog formation, and human health from criteria pollutants. Regardless of quantity consumed, soybean-based lubricants exhibit significant climate change and fossil fuel use benefits; however, eutrophication impacts are much greater due to non-point nutrient emissions. Fundamental tradeoffs in the carbon and nitrogen cycles are addressed in the analysis, demonstrating that a transition to soybean oil may result in climate change benefits at the expense of regional water quality. [ABSTRACT FROM AUTHOR]

Biobased product life cycle assessments (LCAs) have focused largely on energy (fossil fuel) usage and greenhouse gas emissions during the agriculture and production stages. This paper compiles a more comprehensive life cycle inventory (LCI) for use in future bioproduct LCAs that rely on corn or soybean crops as feedstocks. The inventory includes energy, C, N, P, major pesticides, and U.S. EPA criteria air pollutants that result from processes such as fertilizer production, energy production, and on-farm chemical and equipment use. Agroecosystem material flows were modeled using a combination of GREET (the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation model), a linear fractionation model that describes P biogeochemical cycling, and Monte Carlo Analysis. Results show that the dominant air emissions resulted from crop farming, fertilizers, and on-farm nitrogen flows (e.g., N2O and NO). Seed production and irrigation provided no more than 0.002% to any of the inventory emissions or energy flows and may be neglected in future LCAs of corn or soybeans as feedstocks from the U.S. Corn Belt. Lime contributes significantly (17% of total emissions) to air emissions and should not be neglected in bioproduct LCAs. [ABSTRACT FROM AUTHOR]

Intensive agricultural systems are largely responsible for the increase in global reactive nitrogen compounds, which are associated with significant environmental impacts. The nitrogen cycle in agricultural systems is complex and highly variable, which complicates characterization in environmental assessments. Appropriately representing nitrogen inputs into an ecosystem is essential to better understand and predict environmental impacts, such as the extent of seasonally occurring hypoxic zones. Many impacts associated with reactive nitrogen are directly related to annual nitrogen loads, and are not adequately represented by average values that deemphasize extreme years. To capture the inherent variability in agricultural systems, this paper employs Monte Carlo analysis (MCA) to model major nitrogen exports during crop production, focusing on corn-soybean rotations within the U.S. Corn Belt. This approach yields distributions of possible emission values and is the first step in incorporating variable nutrient fluxes into life cycle assessments (LCA) and environmental impact assessments. Monte Carlo simulations generate distributions of nitrate emissions showing that 80% of values range between 15 and 90 kg NO3- N/ha (mean 38.5 kg NO3 N/ha; median 35.7 kg NO3 N/ha) for corn fields and 5-60 kg NO3 N/ha (mean 20.8 kg NO3 N/ha; median 16.4 kg NO3 N/ha) for soybean fields. Data were also generated for grain and residue nitrogen, N2O, NOR, and NH3. Results indicate model distributions are in agreement with available measured emissions. [ABSTRACT FROM AUTHOR]

One approach to address both the environmental and scarcity issues that occur with phosphorus (P) losses from human systems is to improve understanding of the P demands of bio‐based products. Most P demand in the United States is driven by production of crops for animal feed and mineral P feed supplements for animals. In this research, we used the Commodity‐Specific Net Anthropogenic Phosphorus and Nitrogen Inputs (CSNAPNI) model to (1) assess the contributions of individual feed products such as corn, soy, and mineral P supplements to the embodied P of animal products and (2) estimate net anthropogenic phosphorus inputs (NAPIs) for the contiguous United States for two animal P‐intake scenarios. Results show that P supplements may contribute up to 30% of embodied P in pork and dairy products, up to 60% in chicken, and up to 75% in turkey. Other major contributors to animal product‐embodied P are grains, which are responsible for around 60% of embodied P in pork and dairy products, at least 30% in chicken, and at least 20% in turkey products. Results also show that animal P intake is such a significant driver of anthropogenic phosphorus that a reduction of animal P intake by 25% could reduce NAPI to the contiguous United States by 30%. Considering promising research on methods to improve digestibility of both mineral P supplements and grain P in animal diets, these results are encouraging. [ABSTRACT FROM AUTHOR]

The cost and design requirements for transporting satellites and payloads to space using existing orbital technology remain prohibitively high. Yet, quantitative sustainability assessments to evaluate system costs and impacts of existing and proposed orbital transportation systems have been rare. Space elevators are a proposed orbital transportation system intended to safely, gently, and inexpensively transport satellites and other payloads to and from space on a routine daily basis. This life cycle assessment (LCA) was completed to quantify, assess, compare, and suggest improvements to the potential environmental and financial performance of three proposed space elevator system designs, namely i) a One-Tether Initial Space Elevator (the base design) ii) a Two-Tether Initial Space Elevator iii) an Additional One-Tether Space Elevator. A sensitivity analysis to compare the impact of reduced utilization capacity of the space elevator system was also performed. Results indicated the Additional One-Tether Space Elevator scenario had the lowest environmental impact, while the Two-Tether Initial Space Elevator scenario had the lowest production cost per unit mass delivered to orbit. This LCA identified system elements for targeted impact reduction, e.g. operational impacts could be significantly reduced by improving the sustainability of terrestrial transportation delivery systems to the space elevator port. Sensitivity analysis results showed producer cost to be the only impact category with a direct inversely correlated response to reduced capacity; all other impacts showed less sensitivity to utilization reduction. Ultimately, the proposed space elevator design was found to be an environmentally and financially sustainable option for orbital transportation. Further application and refinement of such sustainable engineering and quantitative sustainability assessment methodologies to spacecraft, rocket, and other existing and proposed orbital transportation systems and industries is highly recommended. • The first life cycle assessment of proposed orbital transportation system designs was completed. • The space elevator designs modeled were found to be environmentally and financially sustainable. • Use phase impacts could be reduced by optimizing the terrestrial transportation to the space port. • Space sustainability research is recommended for all orbital transportation systems. [ABSTRACT FROM AUTHOR]

Energy modeling frameworks and scenario analysis help us explore the potential impact of our actions and uncertainties in future energy systems. Despite their importance, there is no systematic procedure for evaluating the scenario development process. In a literature review, we identify two core elements of the scenario development process: internal consistency and diversity which are oftentimes missing from scenarios. To address this gap, we create the Internal consistency and Diversity Scenario Development (IDSD) comparative framework which aims to assess the feasibility and diversity of scenarios for a given energy model. With this framework, we review commonly used energy models and demonstrate our framework on their scenarios. The IDSD comparative framework can serve several purposes absent from previous scenario development work by aiding energy modelers and report writers in crafting high-quality scenarios. First, the IDSD is a reflective tool which can improve the quality of the scenario development process, enabling a comparative assessment of energy models and scenarios. Second, the IDSD can provide guidance to modeling frameworks with existing scenarios and those still in development; this feedback will enable modelers to improve the development and the communication of the limitations of their scenarios. Third, this study has highlighted areas for improvement in the scenario development of some commonly used energy model frameworks. Finally, there is a complete lack of explanation regarding the stakeholder selection process. Addressing these identified items could increase opportunities for advanced energy technology uptake and improve our options for achieving a more resilient energy system. • Develops a novel comparative framework to address gaps in current scenario development practice. • Defines metrics, classifications, criteria, and reflective questions to improve the scenario development process. • Determines that the internal consistency of some scenarios could not be verified due to a lack of documentation. • Identifies a lack of disruptive and normative scenarios, and internally controlled variables across five case studies. [ABSTRACT FROM AUTHOR]

Abstract Agricultural soil management is responsible for a significant portion of net greenhouse gas emission in the United States. Alternative and sustainable agricultural practices are important, as they may help minimize the carbon footprint from agriculture. We developed a framework to account for the carbon footprint (C-footprint), i.e., cumulative greenhouse gas generation of various stages in the cultivation of the crop rotation system of corn-soybean-oats. We obtained real-farm data for this analysis from a biological farming and management company (referred to as bio-farming), and benchmarked this footprint against a conventional farm baseline. The analysis included process modeling i.e., the upstream manufacture of fertilizers and crop applications, local mixing and transport of solid fertilizers (in the bio-farming scenario), on-farm fuel use by farm machinery, as well as agricultural modeling of on-farm soil interactions using the soil & water assessment tool (SWAT). Results varied based on individual crops, and showed that bio-farming practices generated a 44% lower C-footprint for corn, 69% lower footprint for soy and 70% lower footprint for oats compared to conventional farming on a kgCO 2 e/bushel basis. The on-field (N 2 O) emissions contributed most significantly to the total carbon footprint at 70%, 96%, and 89% of the total emissions in corn, soy and oats, respectively. C-footprint results of all crops showed a high dependence on the yield of the respective crop. Sensitivity analyses showed that the application of lime and lack of cover crop increased C-footprint. We identified strategies to reduce emissions from the bio-farming scenario further by implementing management strategies. Highlights • The carbon footprints of corn-soy-oats rotations under conventional v. biological farming practices were assessed. • Stages included fertilizers and crop applications manufacturing, mixing of solid fertilizers, fuel use, field emissions. • Field emissions were modeled using the soil & water assessment tool (SWAT). • Field N 2 O emissions contributed most significantly to the total carbon footprint of all crops. • Bio farming practices showed reduced C-footprints of 44% for corn, 69% for soy and 70% for oats on a bushel basis. [ABSTRACT FROM AUTHOR]

In this article Amy E. Landis and colleagues respond to comments about their report "Sustainability Metrics: Life Cycle Assessment and Green Design in Polymers" that appeared within a 2010 issue of the journal "Environmental Science & Technology." They discusses the aim of the report, which was an examination of two widely used approaches for evaluating the the sustainability of a product or process, including life cycle assessment (LCA) and green design, and their use in ranking polymers.

A hybrid modeling framework was constructed to investigate the uncertainty in modeling the energy consumption of an existing campus building with minimal instrumentation. The hybrid framework consisted of a dynamic model of the building's conditioned spaces, coupled with an empirical model of the building's HVAC system. The empirical model was calibrated using linear regression of available HVAC system temperature and flow measurements from a building automation system to develop estimates of internal loads and relationships between envelope heat gains/losses and indoor/outdoor temperatures. Crabtree Hall, a 40-year-old building at the University of Pittsburgh, was used as an illustrative case study for this approach. A separate data collection time frame was used for empirical model verification in addition to the initial model development time frame. Comparative results from the model showed a 20% normalized RMS deviation for hourly net heating and cooling for the average day in a given month. This close agreement highlights the possibilities of this approach for rapid assessment of energy consumption and retrofit potential in existing buildings. Future work will include additional refinement of the components of energy consumption using mobile equipment to collect targeted measurements at additional locations, as well as cross-checking existing measurement locations. Additional future work should include extending this method to buildings with more complex HVAC systems, such as variable-air-volume systems and multiple thermal zones, to further verify and improve its robustness. [ABSTRACT FROM AUTHOR]

Tertiary treatment is needed to render secondary-treated municipal wastewater usable in power plant cooling systems. Various tertiary treatment options exist to provide different levels of water quality. This paper integrates life cycle inventory emissions from a life cycle assessment approach with direct costs to determine the optimal treatment alternative based on cost-effectiveness and environmental sustainability. The costs of damage due to air emissions released during construction and operation of tertiary treatment alternatives were estimated using a hybrid based approach and were converted to external damage costs. Greenhouse gas emission (CO 2 eq.), acidifying gas emission (SO 2 and NO x ), and particulate matter (PM 2.5 ) emission unit costs were obtained from a Social Carbon Costs study, and cost factors from the Air Pollution Emission Experiments and Policy model were used to determine the total costs of emissions. The sum of average air emissions impact costs for the selected treatment processes were found to be between 5 and 8% of the total costs for tertiary treatment. Accounting for the external air emission costs provides a measure to assess the relative environmental costs of tertiary treatment options for reuse of treated municipal wastewater in cooling systems. Environmental costs of other emissions to air, water and land, as well as benefits stemming from offsetting freshwater withdrawal by reusing treated effluent in power plant cooling systems were not included in the analysis. [ABSTRACT FROM AUTHOR]

Abstract: This study examines three agriculture management practices with the aim of improving the environmental performance of corn-derived products such as bioethanol. Corn production is energy intensive and contributes to water quality degradation and global warming, thus affecting the environmental impact of corn-derived ethanol. Life Cycle Assessment (LCA) is used to quantify and compare the environmental impacts of three management strategies: tillage, fertilizer choices and the use of buffer strips to sequester nutrients. Detailed energy, carbon, nitrogen and phosphorus inventories are compiled to represent corn production scenarios within the US Corn Belt. The LCA was developed using GREET 1.8 (Greenhouse Gases, Regulated Emissions, and Energy use in Transportation) and emission factors with statistical analyses to estimate energy consumption, associated air emissions, and aqueous nutrient runoff potentials. Results show that using manure fertilizers as opposed to synthetic fertilizers requires less energy, however the use of manure generates more CH4, N2O, CO2 and results in more variable concentrations of nitrogen and phosphorus leaching from farmlands. No tillage emits less greenhouse gas emissions, sequesters more soil organic carbon and slightly reduces nutrient runoff compared with conventional tillage practices. Building buffer strips of certain widths is an efficient way to reduce N and P discharge to surrounding waters with minimal effect on the energy or global warming profile. Based on the results of the LCA studies, replacing conventional tillage with no till, and installing buffer strips can improve environmental performances of corn derived ethanol. [Copyright &y& Elsevier]

Highlights: [•] This study investigated a cradle-to-gate microalgal biodiesel and its co-products. [•] Ozone depletion, global warming, smog, acidification and eutrophication potentials were assessed. [•] The market opportunities for each co-product were examined. [•] The scenario with the least life-cycle environmental impacts has the highest net energy ratio. [•] The scenario also had the highest total income indicating their co-products market potential. [ABSTRACT FROM AUTHOR]

• A variable discount rate is used in the marginal net present value calculations. • Existing space heating and cooling equipment impact resident upgrade options. • Electric furnaces and boilers increase lifetime costs for most residents. • Inflation Reduction Act rebates allow for savings with heat pump installations. • Decreased capital costs, not decreased utility rates impact upgrade options more. A major step towards residential building decarbonization is the electrification of natural gas space heating. Current inequities such as limited access to cooling technologies and high energy burden can be addressed in transition if we take steps now to understand the economic impacts of different electric technologies. This study presents a novel high-resolution techno-economic model, the Marginal Net Present Value Upgrade Analysis model, which improves upon existing literature that examines the economics of electrifying space heating through a more detailed cost calculation and the use of a variable discount rate. Results show that 1) electrifying with heat pumps is only recommended for owners who are replacing a natural gas furnace and central AC system, 2) renters are highly vulnerable in this transition in that electric resistance technologies are the least capital intensive technology for landlords to install, with renters bearing the increased operational cost, 3) rebates from the Inflation Reduction Act of 2022 allow most qualifying landlords and owners to install even the highest efficiency heat pumps at a net savings when compared to the baseline heating and cooling system, and 4) reducing capital costs are more critical than altering utility rates to achieve high heat pump penetration. The model developed herein can support decision-making related to electrification and energy efficiency policy and rulemaking and will give insight into the impact residential building electrification can have on marginalized communities. [ABSTRACT FROM AUTHOR]

Highlights: [•] Conducted a life cycle assessment (LCA) of microalgal diesel from PBR to combustion. [•] Compared the results with other existing LCA results of petroleum and other biodiesels. [•] Assessed the current Renewable Fuel Standard (RFS2). [•] Proposed an approach to set emission thresholds for eutrophication (EP) and smog formation potentials (PSP). [•] Future RFS should include a life-cycle emissions threshold for EP and PSP. [ABSTRACT FROM AUTHOR]

Abstract: Bio-based polymers have become feasible alternatives to traditional petroleum-based plastics. However, the factors that influence the sustainability of bio-based polymers are often unclear. This paper reviews published life cycle assessments (LCAs) and commonly used LCA databases that quantify the environmental sustainability of bio-based polymers and summarizes the range of findings reported within the literature. LCA is discussed as a means for quantifying environmental impacts for a product from its cradle, or raw materials extraction, to the grave, or end of life. The results of LCAs from existing databases as well as peer-reviewed literature allow for the comparison of environmental impacts. This review compares standard database results for three bio-based polymers, polylactic acid (PLA), polyhydroxyalkanoate (PHA), and thermoplastic starch (TPS) with five common petroleum derived polymers. The literature showed that biopolymers, coming out of a relatively new industry, exhibit similar impacts compared to petroleum-based plastics. The studies reviewed herein focused mainly on global warming potential (GWP) and fossil resource depletion while largely ignoring other environmental impacts, some of which result in environmental tradeoffs. The studies reviewed also varied greatly in the scope of their assessment. Studies that included the end of life (EOL) reported much higher GWP results than those that limited the scope to resin or granule production. Including EOL in the LCA provides more comprehensive results for biopolymers, but simultaneously introduces greater amounts of uncertainty and variability. Little life-cycle data is available on the impacts of different manners of disposal, thus it will be critical for future sustainability assessments of biopolymers to include accurate end of life impacts. [Copyright &y& Elsevier]

Abstract: Service industries continue to be to be a driving force economically, both within the US and globally, yet their environmental impacts still tend to be overlooked. This article presents a hybrid life cycle assessment case study to assess and quantify the life cycle impacts of an engineering service firm. The data for the hybrid LCA of the firm''s activities and operations was collected for one fiscal year, from January 2009 to December 2009. Data collection methods include an energy audit, personnel survey, and assessment of waste management practices. The results of the case study show that the impacts of employee travel and transportation as well as the building premises are the major contributors to the environmental impact of a service industry (40% and 24% of GWP, respectively) and should be the areas targeted for improvements to reduce life-cycle impacts of similar service firms. The study also reveals that in order to make specific targeted reductions to a firm''s life-cycle impacts, more in depth evaluation of certain activities, such as workstation energy consumption, can be essential to identifying unnecessary wastes of resources. [Copyright &y& Elsevier]

This study analyzed the environmental impacts of the materials phase of a net-zero energy building. The Center for Sustainable Landscapes (CSL) is a three-story, 24,350 square foot educational, research, and administrative office in Pittsburgh, PA, USA. This net-zero energy building is designed to meet Living Building Challenge criteria. The largest environmental impacts from the production of building materials is from concrete, structural steel, photovoltaic (PV) panels, inverters, and gravel. Comparing the LCA results of the CSL to standard commercial structures reveals a 10% larger global warming potential and a nearly equal embodied energy per square feet, largely due to the CSL's PV system. As a net-zero energy building, the environmental impacts associated with the use phase are expected to be very low relative to standard structures. Future studies will incorporate the construction and use phases of the CSL for a more comprehensive life cycle perspective. [ABSTRACT FROM AUTHOR]

Many studies have compared corn-based ethanol to cellulosic ethanol on a per unit basis and have generally concluded that cellulosic ethanol will result in fewer environmental consequences, including nitrate (NO3-) output. This study takes a system-wide approach in considering the NO3- output and the relative areal extent of hypoxia in the Northern Gulf of Mexico (NGOM) due to the introduction of additional crops for biofuel production. We stochastically estimate NO3- loading to the NGOM and use these results to approximate the areal extent of hypoxia for scenarios that meet the Energy Independence and Security Act of 2007's biofuel goals for 2015 and 2022. Crops for ethanol include corn, corn stover, and switchgrass; all biodiesel is assumed to be from soybeans. Our results indicate that moving from corn to cellulosics for ethanol production may result in a 20-percent decrease (based on mean values) in NO3- output from the Mississippi and Atchafalaya River Basin (MARB). This decrease will not meet the EPA target for hypoxic zone reduction. An aggressive nutrient management strategy will be needed to reach the 5000 km² areal extent of hypoxia in the NGOM goal set forth by the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force even in the absence of biofuels, given current production to meet food, feed, and other industrial needs. [ABSTRACT FROM AUTHOR]

Food waste and biopolymers, plastics derived from plants, are unexploited sources of energy when discarded in landfills without energy recovery. In addition, polylactic acid (PLA) and food waste have complimentary characteristics for anaerobic digestion; both are organic and degrade under anaerobic conditions. Lab-scale reactors were set up to quantify the solubilization of pretreated amorphous and crystalline PLA. Biochemical methane potential (BMP) assays were performed to quantify CH4 production from both treated and untreated PLA in the presence of food waste and anaerobic digested sludge. Amorphous and crystalline PLA reached near-complete solubilization at 97% and 99%, respectively, when alkaline pretreatment was applied. The PLA that received alkaline treatment produced the most of CH4 throughout the run time of 70 days. The PLA without treatment resulted in 54% weight reduction after anaerobic digestion. Results from this study show that alkaline pretreatment has the greatest solid reduction of PLA and maximum production of CH4 when combined with food waste and anaerobic digested sludge. [ABSTRACT FROM AUTHOR]

Abstract This research used four-parameter multi-cycle logistic growth curve models on US Energy Information Agency annual data from 1949 to 2015 to produce fixed condition forecasts of US energy production and consumption to 2040. These models and forecasts were used to assess the ability of US energy production sources to meet demand, to anticipate production and technology challenges, and to make general policy recommendations. The logistic fixed condition forecasts indicated the ongoing increases in total US energy production dominated by crude oil and natural gas production will likely peak in 2017 (at 95.0 quadrillion “quad” BTU) then rapidly decrease through 2040 (at 36.2 quad BTU), while total US energy consumption indicated an ongoing plateau (at 98.1 quad BTU). New growth cycles not evident in the 2015 data will certainly occur, mitigating the decline in energy production before 2040. However, without adequate foresight and preemptive action, it is possible that new production growth would not be adequate to reverse the decline given historical growth trends. Therefore, in addition to continued increases in energy efficiency, reductions in use, and implementation of carbon management technologies, direct effort towards the sustainable development of substantial new growth cycles in all energy production sources (through adequate investment of resources) should be a priority of the US energy industry, policy makers, and the public alike. Graphical abstract fx1 Highlights • S-shaped growth curves (with plateaus) fit renewable and nuclear energy production. • Bell-shaped growth curves (with peaks/declines) fit fossil fuel energy production. • The total US energy production model indicated a 95 quadrillion BTU peak in 2017. • The total US energy consumption model indicated an ongoing 98 quad BTU plateau. • To meet projected demand, new growth cycles are needed for US energy production. [ABSTRACT FROM AUTHOR]

Background: While petroleum-based plastics are extensively used in health care, recent developments in biopolymer manufacturing have created new opportunities for increased integration of biopolymers into medical products, devices and services. This study compared the environmental impacts of single-use disposable devices with increased biopolymer content versus typically manufactured devices in hysterectomy. Methods: A comparative life cycle assessment of single-use disposable medical products containing plastic(s) versus the same single-use medical devices with biopolymers substituted for plastic(s) at Magee-Women's Hospital (Magee) in Pittsburgh, PA and the products used in four types of hysterectomies that contained plastics potentially suitable for biopolymer substitution. Magee is a 360-bed teaching hospital, which performs approximately 1400 hysterectomies annually. Results: There are life cycle environmental impact tradeoffs when substituting biopolymers for petroplastics in procedures such as hysterectomies. The substitution of biopolymers for petroleum-based plastics increased smog-related impacts by approximately 900% for laparoscopic and robotic hysterectomies, and increased ozone depletion-related impacts by approximately 125% for laparoscopic and robotic hysterectomies. Conversely, biopolymers reduced life cycle human health impacts, acidification and cumulative energy demand for the four hysterectomy procedures. The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects. However, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts of products and devices made using biopolymers. Conclusions: The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects; however, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts. [ABSTRACT FROM AUTHOR]

A comparative cradle-to-gate life cycle assessment (LCA) including raw material acquisitions, rubber production and transportation of synthetic rubber (SBR) and two natural rubbers, namely imported Hevea and US-grown guayule, was conducted to quantify environmental impacts and to identify area(s) of environmental improvement. The use of co-products from the two natural rubbers as a source of energy was explored for their impacts and energy offset potential. Three environmental impact categories-ozone depletion (ODP), global warming (GWP), and acidification potential (AP)-and net energy were evaluated. Results indicated that guayule rubber had a lower ODP impact compared to SBR, and lower GWP and AP impacts compared to Hevea rubber. The Hevea rubber production with biodiesel co-product from seed oil scenario had the highest GWP and AP impacts, whereas guayule rubber production with bio-oil co-product from bagasse had the highest ODP impact. Only the scenario of Hevea rubber production with biodiesel production indicated an overall energy production of 3.25 MJ/kg rubber, whereas all other scenarios indicated a net energy consumption. However, co-products contributed to reduction in total energy consumed in every scenario that was investigated. The most promising guayule rubber scenario among the six examined was that with electricity production from bagasse, as it contributed the least to all three impact categories and yielded the most net energy. Sensitivity analysis on this most promising guayule scenario indicated rubber yield, water use and electricity for water pumping in guayule irrigation as the key parameters that have significant impacts on results. [ABSTRACT FROM AUTHOR]

As continued globalization of the world's economic, environmental, and societal interactions strains the planet to meet anthropogenic demands, universities are striving to integrate sustainability education into engineering curricula intended to prepare students for global challenges facing today's engineers. Concurrently, the Accreditation Board for Engineering and Technology (ABET) has potential changes related to outcomes related to sustainability. Current practice is to evaluate many student educational outcomes, including those in sustainability, at the end of collegiate careers, primarily through the senior design course. This study compares results from the application of a comprehensive holistic sustainability rubric assessment tool to three years of student projects in two stand-alone sustainable engineering courses and two senior design courses, intended to assess dissimilarities in student outcomes and locate causality, in the context of sustainability. The authors present two potential factors contributing to discrepancies in student outcomes: (1) rubrics do not contain clear elements of sustainability; and (2) senior design course syllabuses are full, and offer strategic approaches to overcoming these barriers institutionally and nationally. [ABSTRACT FROM AUTHOR]

While hospitals, sustainable healthcare organizations, and recent peer-reviewed publications have assessed the sustainability of medical products and services, the healthcare industry lacks a framework to effectively inform environmental decision making and quantitatively assess the success of sustainability initiatives for medical products and services. Several recent publications have even expressed a need for better ways to quantify sustainable healthcare practices. To address these needs, this research compared the cradle-to-grave environmental and economic impacts of some of the most common recommendations from checklists: reusable versus disposable medical products, and changes to common medical services. Salient results and conclusions from recent studies focusing on the environmental and economic impacts of various reusable versus disposable medical products and different medical services were synthesized and prioritized. All relevant results related to environmental and economic impacts of reusable versus disposable medical products and the analyzed medical services were also correlated with existing sustainable checklists. The results showed that reusable products were less expensive their single-use disposable alternatives. The dental bur also required the least amount of water for its associated cleaning processes, had the lowest total embodied energy, and had the lowest associated greenhouse gas emissions. These outcomes were likely due to the fact the burs were, by far, the smallest examined product. Based on the results derived from the study, healthcare checklists should be updated to include: optimizing the reusability of medical products; reduce products utilized in custom packs; and evaluating energy recovery potential of utilized products. The results of this study indicate that sustainable healthcare checklists be further validated with more environmental and economic life-cycle analyses related to medical products and services. The primary aim of this paper is to assist hospital employees and administrators with making more informed decisions about the sustainability of their products and services. The scientific value of this paper is underscored by a novel aggregation of life cycle assessment studies pertaining to medical devices and services in order to draw conclusions regarding the overall sustainability of those medical devices and services. [ABSTRACT FROM AUTHOR]

This research evaluates the addition of alkaline amendments to enhance the degradation of polylactic acid polymers (PLA) in compost conditions. The use of compostable biopolymers is increasing in part because they are advertised as compostable. However, PLA degrades slowly compared to the organic wastes in compost and even when processed in commercial composting facilities may not fully break down. This results in the accumulation of biopolymers in compost facilities and increased difficulty in identifying and removing contamination from traditional plastics. Alkaline amendments were used to accelerate the degradation of two PLA products in compost conditions. Six flasks containing food scraps, compost inoculant, and an alkaline amendment were set up as bioreactors with half containing clear PLA and the others including opaque PLA. The six bioreactors were incubated for 22 days. The mass loss and final visual inspection, including microscopy, showed increased degradation within the bioreactors containing the alkaline treatments. These results show that the addition of alkaline amendment to composting systems may enable more effective processing of biopolymers, expanding the range and quantity of wastes that can be processes. The enhanced degradation of biopolymers in compost may enable greater diversion rates for institutions and cities by enabling the acceptance of biopolymers and any mixed organics stream which includes biopolymers wastes. [ABSTRACT FROM AUTHOR]

Embedded-class processors found in commodity palmtop computers continue to become increasingly capable. Moreover, wireless connectivity in these systems provides new opportunities in designing flexible and smarter wireless sensor networks (WSNs). In this paper, we present Lynx, a self-organizing wireless sensor network framework. Leveraging palmtop systems as sensor hubs, Lynx provides fundamental functionality to make a distributively managed, customizable WSN system implementation. Second, we describe Ocelot, a mobile distributed grid-like computing engine for commodity palmtop platforms. The combination of Lynx and Ocelot provides sensor nodes that are capable of collecting, recording, processing, and communicating data without any central server support. Significant energy savings can be achieved for light to medium weight tasks through the Lynx and Ocelot combined system compared to traditional server-class grid-solutions such as BOINC. We demonstrate Lynx and Ocelot in the context of life-cycle building energy usage. [ABSTRACT FROM AUTHOR]

Producing biofuel feedstock on marginal lands is a viable way to offset fossil fuel production, global warming, and other adverse environmental impacts, while at the same time performing positive ecosystem services by reclaiming unused areas with value producing activities. This research study explored low-input production of sunflower biodiesel feedstock on abandoned mine land (AML) from coal mining refuse treated with bauxite residue (alkaline clay) through the lens of Life Cycle Assessment (LCA). An attributional LCA was conducted from the gate of an aluminum production facility (which produces the bauxite residue), through AML amelioration and low-input agricultural activities, to the gate of a biodiesel production facility. A 26 ha (ha) coal mine refuse pile located in Mather, PA, (91 km south of Pittsburgh), was used as an example location. Analysis of published agricultural data and greenhouse research led to a conservative sunflower oilseed yield of 500 kg/ha estimate, with a subsequent biodiesel yield of 190 kg/ha (217 l/ha). Results show substantial impact from the initial soil amendment process, however, when compared to complete restoration of the AML and other similar fuel production activities, overall environmental impacts over a twenty-year production cycle are sensible. An alternative allocation of the bauxite residue transport (i.e. associating transport impacts to aluminum industry) and addition of other fuel conversion pathways would show an improved energy return and better environmental outlook from biofuel production on AML. [ABSTRACT FROM AUTHOR]

A well-to-wheel (WTW) life cycle assessment (LCA) model is developed to evaluate the environmental profile of producing liquid transportation fuels via fast pyrolysis of perennial grasses: switchgrass and miscanthus. The framework established in this study consists of (1) an agricultural model used to determine biomass growth rates, agrochemical application rates, and other key parameters in the production of miscanthus and switchgrass biofeedstock; (2) an ASPEN model utilized to simulate thermochemical conversion via fast pyrolysis and catalytic upgrading of bio-oil to renewable transportation fuel. Monte Carlo analysis is performed to determine statistical bounds for key sustainability and performance measures including life cycle greenhouse gas (GHG) emissions and Energy Return on Investment (EROI). The results of this work reveal that the EROI and GHG emissions (gCO2e/MJ-fuel) for fast pyrolysis derived fuels range from 1.52 to 2.56 and 22.5 to 61.0 respectively, over the host of scenarios evaluated. Further analysis reveals that the energetic performance and GHG reduction potential of fast pyrolysis-derived fuels are highly sensitive to the choice of coproduct scenario and LCA allocation scheme, and in select cases can change the life cycle carbon balance from meeting to exceeding the renewable fuel standard emissions reduction threshold for cellulosic biofuels. [ABSTRACT FROM AUTHOR]

Guayule ( Parthenium argentatum Gray) is an arid-adapted, low-input perennial shrub native to Mexico and southern Texas that has received considerable attention as an alternative source of natural rubber. It has potential to replace the most common types of rubbers, including synthetic rubber derived from petroleum and natural rubber, which is tapped from Hevea ( Hevea brasiliensis ) trees grown in tropical regions, primarily Southeast Asia. The guayule plant produces natural rubber in its bark parenchyma cells and the shrub is processed to extract the latex. Guayule rubber is comparable in quality to Hevea natural rubber and the residual, non-latex guayule plant material can be transformed into valuable co-products, such as bioenergy. This review introduces the reader to guayule rubber production (agriculture, processing and products) and explores the sustainability implications of guayule rubber commercialization related to the three pillars of sustainability, including environmental impacts of rubber production, economic barriers and advantages, and social implications. The review highlights areas of focus that could be leveraged to help guayule become a more sustainable source of natural rubber. Guayule rubber provides an opportunity to lower the environmental impacts of a major commodity, to develop an industry to support the local U.S, economy, and to reduce U.S. dependence on non-renewable petroleum sources and rubber imports. Proposed recommendations to further support guayule sustainability include improving the efficiency of agricultural and processing activities, utilization of guayule co-products to improve economics of guayule cultivation, and the establishment of a secure guayule rubber supply at a production level that could consistently meet rubber demands. A better understanding of guayule rubber life-cycle impacts could be a way to reduce the environmental footprint of guayule rubber products and expedite its commercialization. [ABSTRACT FROM AUTHOR]

Disposable materials contribute to healthcare's estimated production of 33 pounds of waste per patient bed per day or approximately 5.9 million tons of waste each year. The shift toward disposable materials was initially driven by a variety of factors including the potential for infection control, convenience, and cost. The current use of single-use disposables in healthcare, however, has become costly, wasteful, and to some extent, unnecessary. Disposable custom packs, a set of products prepackaged for a specific procedure to reduce time and error, are utilized in nearly every medical procedure performed in the US and internationally. This study analyzed 15 custom packs from geographically diverse hospitals using life cycle assessment and design for the environment. Polypropylene, the material used to make gowns and drapes, was the most prominent material by weight, followed by cotton. However, the life cycle assessment results show that cotton composed the largest portion of environmental impacts in every category. Finally, a new green custom pack was designed. By using tools and strategies such as life cycle assessment and design for the environment, healthcare institutions can make educated streamlining efforts for their disposable custom packs. [ABSTRACT FROM AUTHOR]

This study evaluated seven different waste management strategies for venue-based events and characterized the impacts of event waste management via waste audits and the Waste Reduction Model (WARM). The seven waste management scenarios included traditional waste handling methods (e.g. recycle and landfill) and management of the waste stream via composting, including purchasing where only compostable food service items were used during the events. Waste audits were conducted at four Arizona State University (ASU) baseball games, including a three game series. The findings demonstrate a tradeoff among CO 2 equivalent emissions, energy use, and landfill diversion rates. Of the seven waste management scenarios assessed, the recycling scenarios provide the greatest reductions in CO 2 eq. emissions and energy use because of the retention of high value materials but are compounded by the difficulty in managing a two or three bin collection system. The compost only scenario achieves complete landfill diversion but does not perform as well with respect to CO 2 eq. emissions or energy. The three game series was used to test the impact of staffed bins on contamination rates; the first game served as a baseline, the second game employed staffed bins, and the third game had non staffed bins to determine the effect of staffing on contamination rates. Contamination rates in both the recycling and compost bins were tracked throughout the series. Contamination rates were reduced from 34% in the first game to 11% on the second night (with the staffed bins) and 23% contamination rates at the third game. [ABSTRACT FROM AUTHOR]

The healthcare sector is a driver of economic growth in the U.S., with spending on healthcare in 2012 reaching $2.8 trillion, or 17% of the U.S. gross domestic product, but it is also a significant source of emissions that adversely impact environmental and public health. The current state of the healthcare industry offers significant opportunities for environmental efficiency improvements, potentially leading to reductions in costs, resource use, and waste without compromising patient care. However, limited research exists that can provide quantitative, sustainable solutions. The operating room is the most resource-intensive area of a hospital, and surgery is therefore an important focal point to understand healthcare-related emissions. Hybrid life cycle assessment (LCA) was used to quantify environmental emissions from four different surgical approaches (abdominal, vaginal, laparoscopic, and robotic) used in the second most common major procedure for women in the U.S., the hysterectomy. Data were collected from 62 cases of hysterectomy. Life cycle assessment results show that major sources of environmental emissions include the production of disposable materials and single-use surgical devices, energy used for heating, ventilation, and air conditioning, and anesthetic gases. By scientifically evaluating emissions, the healthcare industry can strategically optimize its transition to a more sustainable system. [ABSTRACT FROM AUTHOR]

Highlights: [•] Energy demand of 122 microalgae biomass production scenarios were compared. [•] Choice of harvesting technology affected energy demand of other phases. [•] Raceway ponds, settling, and chamber filter press consumed the least energy. [•] Total energy demand for biomass production depends on final concentration. [Copyright &y& Elsevier]

Abstract: To meet rising energy demands in a sustainable manner, the United States Renewable Fuel Standard 2 (RFS2) mandates the production of 3.78billion L (1billion gallons) of biomass-based biodiesel per year by 2020. Urban marginal lands, herein defined as lots with poor agricultural potential and unfit for residential purposes, can be used to cultivate biodiesel feedstock, which can contribute toward the RFS2. GIS is particularly well suited to identify the amount and location of these urban marginal lands. Biofuel crop production is one way for urban neighborhoods to reclaim vacant, blighted properties and also generate green energy for consumption. Combining soil classification data with urban development data, a GIS framework was developed to determine the amount of urban marginal land available in Pittsburgh, Pennsylvania. This location was chosen because small-scale sunflower crops are already being grown on urban marginal lands for biodiesel production. This paper evaluates two methods for identifying marginal lands for biofuel cultivation. The first is based on NRCS soil classifications derived from previous literature approaches. When compared with the locations of a nonprofit that is actually cultivating marginal lands, the NRCS soil classification method captures less than 35% of the marginal lands being cultivated in Pittsburgh, and 2400ha (6000acres) of marginal land in total that could be used to grow sunflowers for biodiesel production. We modify the NRCS marginal soil classification method to include certain types of urban commercial lands and lands not currently classified as marginal, and create a framework that identifies almost 90% of the marginal lands currently under cultivation in Pittsburgh, with approximately 3500ha (8700 acres) of available marginal lands. Pittsburgh’s marginal lands could be used to produce up to 129,000L (34,100gallons) of sunflower-based biodiesel. This could contribute a maximum of 0.1% to Pennsylvania’s biofuel mandate and 0.003% to the RFS2. While a city’s individual contribution may be incremental on the national scale, multiple cities and regions may be able to contribute to the RFS2. In addition, there is an unquantified social benefit that results from community engagement and revitalization, which is part of the mission of the Pittsburgh nonprofit. [Copyright &y& Elsevier]

Abstract: This study introduces life cycle assessment as a tool to analyze one aspect of sustainability in healthcare: the birth of a baby. The process life cycle assessment case study presented evaluates two common procedures in a hospital, a cesarean section and a vaginal birth. This case study was conducted at Magee-Womens Hospital of the University of Pittsburgh Medical Center, which delivers over 10,000 infants per year. The results show that heating, ventilation, and air conditioning (HVAC), waste disposal, and the production of the disposable custom packs comprise a large percentage of the environmental impacts. Applying the life cycle assessment tool to medical procedures allows hospital decision makers to target and guide efforts to reduce the environmental impacts of healthcare procedures. [Copyright &y& Elsevier]

This study evaluates the efficacy of green design principles such as the "12 Principles of Green Chemistry," and the "12 Principles of Green Engineering" with respect to environmental impacts found using life cycle assessment (LCA) methodology. A case study of 12 polymers is presented, seven derived from petroleum, four derived from biological sources, and one derived from both. The environmental impacts of each polymer's production are assessed using LCA methodology standardized by the International Organization for Standardization (ISO). Each polymer is also assessed for its adherence to green design principles using metrics generated specifically for this paper. Metrics include atom economy, mass from renewable sources, biodegradability, percent recycled, distance of furthest feedstock, price, life cycle health hazards and life cycle energy use. A decision matrix is used to generate single value metrics for each polymer evaluating either adherence to green design principles or life-cycle environmental impacts. Results from this study show a qualified positive correlation between adherence to green design principles and a reduction of the environmental impacts of production. The qualification results from a disparity between biopolymers and petroleum polymers. While biopolymers rank highly in terms of green design, they exhibit relatively large environmental impacts from production. Biopolymers rank 1, 2, 3, and 4 based on green design metrics; however they rank in the middle of the LCA rankings. Polyolefins rank 1, 2, and 3 in the LCA rankings, whereas complex polymers, such as PET, PVC, and PC place at the bottom of both ranking systems. [ABSTRACT FROM AUTHOR]