Comparison Of Greenhouse Gas Emissions Research Articles

Energy use and greenhouse gas emissions in selected tea factories in Kenya

Tea sector is a major contributor to Kenya’s economy through foreign exchange via export. However, extensive amount of energy is required to produce one kilogram of tea, making tea processing energy-intensive. Comparing greenhouse gas emissions from different types of energy consumed in tea factories is imperative to enable policymakers make informed intervention in emission reduction. Reducing greenhouse gas emissions in tea factories is one of the pathways to meeting Kenya’s nationally determined 32% reduction of carbon emissions by 2030 and commitment to the Paris Agreement. This paper assesses greenhouse gas emissions from different sources of energy used in four tea factories in Kenya. The Intergovernmental Panel on Climate Change emission factor is used to calculate the total emissions of each type of energy used for 5 years. Life cycle assessment using SimaPro 8 software, Eco-indicator 99 method and Eco invent database was used to assess the specific compound causing the emission. The findings reveal that the 5-year greenhouse gas emissions by biogas, solar, wood, briquettes, and electricity are 336.111, 7.108, 3057.729, and 1,338.28 kg CO2/MWh, respectively. Firewood has the highest concentration of carbon dioxide, while solar energy has the least. Analysis of variance confirms significant difference (0.05>p = 0.0272) in greenhouse gas emissions from the different energy sources. Post-hoc analyses shows a significant difference in emissions between solar and firewood (p<0.0125) and no significant difference between other sources of energy. The key environmental hotspot is the energy intensive processes such as drying involved in tea production and processing, which leads to consumption of fossil fuel in the factories. To reduce such key hotspot, switching to renewable energy sources is key. Sustainability in the tea sector can therefore be achieved through switching to macadamia briquettes as a source of thermal energy and a combination of electricity and solar for electrical energy.

Assessment of Greenhouse Gas Emissions isplaced by Molten Salt Storage in CSP Plants Compared to Conventional Power Plants

Molten salts are the most widely used thermal energy storage system in Concentrated Solar Power (CSP) plants, accounting for 50% of the installed capacity. Many studies have conducted life cycle assessments of the Greenhouse Gas (GHG) emissions produced within the CSP ecosystem; however, it has not yet been standardized for molten salt storage. This study compares GHG emissions of molten salt storage in CSP with conventional coal and natural gas power plants, to measure the environmental impact they can have in the CSP ecosystem. This was achieved with the use of simulations for 48 operational CSP plants worldwide using the system advisor model with their respective operation conditions. Results show that for the three configurations studied, CSP plants would result in annual 3,99 MMtCO2eq of emissions displaced when compared to a coal power plant and 1,61 MMtCO2eq compared to a natural gas power plant.

Complete long-term monitoring of greenhouse gas emissions from a full-scale industrial wastewater treatment plant with different cover configurations

The greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs), consisting mainly of methane (CH4) and nitrous oxide (N2O), have been constantly increasing and become a non-negligible contributor towards carbon neutrality. The precise evaluation of plant-specific GHG emissions, however, remains challenging. The current assessment approach is based on the product of influent load and emission factor (EF), of which the latter is quite often a single value with huge uncertainty. In particular, the latest default Tier 1 value of N2O EF, 0.016 ± 0.012 kgN2O–N kgTN−1, is estimated based on the measurement of 30 municipal WWTPs only, without involving any industrial wastewater. Therefore, to resolve the pattern of GHG emissions from industrial WWTPs, this work conducted a 14-month monitoring campaign covering all the process units at a full-scale industrial WWTP in Shanghai, China. The total CH4 and N2O emissions from the whole plant were, on average, 447.7 ± 224.5 kgCO2-eq d−1 and 1605.3 ± 2491.0 kgCO2-eq d−1, respectively, exhibiting a 5.2- or 3.9-times more significant deviation than the influent loads of chemical oxygen demand (COD) or total nitrogen (TN). The resulting EFs, 0.00072 kgCH4 kgCOD−1 and 0.00211 kgN2O–N kgTN−1, were just 0.36% of the IPCC recommended value for CH4, and 13.2% for N2O. Besides, the parallel anoxic-oxic (A/O) lines of this industrial WWTP were covered in two configurations, allowing the comparison of GHG emissions from different odor control setup. Unit-specific analysis showed that the replacement of enclosed A/open O with enclosed A/O reduced the CH4 EF by three times, from 0.00159 to 0.00051 kgCH4 kgCOD−1, and dramatically decreased the N2O EF by an order of magnitude, from 0.00376 to 0.00032 kgN2O–N kgTN−1, which was among the lowest of all full-scale WWTPs.

Comparison of Greenhouse Gas Emissions, Nitrogen Intensity, Gross Margin, and Land Use Occupation between Comparable Conventional and Organic Managed Dairy Farms

In this study, 200 Norwegian dairy farms were analyzed over three years to compare greenhouse gas emissions, nitrogen (N) intensity, gross margin, and land use occupation between organically and conventionally managed farms. Conventionally managed farm groups were constructed based on propensity matching, selecting the closest counterparts to organically managed farms (n=15). These groups, each containing 15 farms, were differentiated by an increasing number of matching variables. The first group was matched based on geographical location, milk quota, and milking cow units. In the second match, the proportion of milking cows in the total cattle herd was added, and in the third, the ratio of milk delivered to milk produced and concentrate usage per dairy cow were included. The analysis showed that the conventionally managed farms (n=185) had higher greenhouse gas emissions (1.42 vs 0.98 kg CO2 per 2.78 MJ of edible energy from milk and meat, calculated as GWP100-AR4) and higher N intensity (6.9 vs 5.0 kg N input per kg N output) compared to the organic farms (N=15). When comparing emissions per kg of energy-corrected milk (ECM) delivered, conventional farms also emitted more CO2 (1.07 vs 0.8 kg CO2 per kg ECM). Furthermore, conventionally managed farms showed lower gross margins both in terms of NOK per 2.78 MJ edible energy delivered (5.8 vs 6.5 NOK) and per milking cow unit (30 100 vs 34 400 NOK), and they used less land (2.9 vs 3.6 m² per 2.78 MJ edible energy delivered) compared to organic farms. No differences were observed among the three conventionally managed groups in terms of emissions, N intensity, land use occupation, and gross margin.

Comparison of greenhouse gas emissions from sheep measured using both respiration and portable accumulation chambers

Methane (CH4) is a potent gas produced by ruminants, and new measurement techniques are required to generate large datasets suitable for genetic analysis. One such technique are portable accumulation chambers (PAC), a short-term sampling method. The objectives of the current study were to explore the relationship between CH4 and carbon dioxide (CO2) output measured using both PAC and respiration chambers (RC) in growing lambs, and separately investigate the relationship among CH4, CO2 and measured ad libitum DM intake (DMI). Methane, CO2 and DMI were measured on 30 Suffolk and 30 Texel ewe lambs (age 253 ± 12 days) using the RC and PAC sequentially. The experiment was conducted over a 14-day period, with DMI measured from days 1 to 14; measurements in RC were conducted from days 10 to 12, while measurements in PAC were taken twice, the day immediately prior to the lambs entering the RC (day 9; PAC Pre-RC) and on the day lambs exited the RC (day 13; PAC Post-RC). Greater CH4 and CO2 output was measured in the RC than in the PAC (P < 0.01); similarly mean CH4 yield was greater when measured in the RC (15.39 ± 0.452 g CH4/kg DMI) compared to PAC (8.01 ± 0.767 g CH4/kg DMI). A moderate correlation of 0.37 was found between CH4 output measured in PAC Pre-RC and the RC, the corresponding regression coefficient of CH4 output measured in the RC regressed on CH4 output measured in PAC Pre-RC was close to unity (0.74; SE 0.224). The variance of CH4 and CO2 output within the measurement technique did not differ from each other (P > 0.05). Moderate to strong correlations were found between CH4 and CO2 per kg of live weight and CH4 and CO2 yield. Results from this study highlight the suitability of PAC as a ranking tool to rank animals based on their gaseous output when compared to the RC. However, repeated measurements separated by several days may be beneficial if precise rankings are required. Given the close to unity regression coefficient of CH4 output measured in the RC regressed on CH4 output measured in PAC Pre-RC suggests that PAC could also be potentially used to estimate absolute CH4 output; however, further research is required to substantiate this claim. When DMI is unknown, CH4 and CO2 per kg of live weight are a suitable alternative to the measurement of CH4 and CO2 yield.

Quantifying and Comparing Greenhouse Gas Emissions in Monsoon Rice Production: A Comprehensive Analysis of Transplanting and Broadcasting Sowing Methods in Myanmar

Introduction Rice is a staple food, an economic crop, and the second-highest source of greenhouse gas (GHG) emissions in the agricultural sector in Myanmar. To develop the rice sector in a sustainable way, this study aimed to determine the comparative GHG emissions between the two major sowing methods used in monsoon rice production. Methods Next, comparative GHG emissions analysis was done by using the Student t-test. This study first quantified GHG emissions from land preparation to straw burning by using emission factors for agricultural inputs and the formulation, default values, and scaling factors of a carbon footprint calculator customized for rice products (CF-Rice). Results Soil and water management was the largest contributor among the management practices in monsoon rice production and accounted for 64.8% of the total GHG emissions. At 4,479.5 kg CO2 eq. ha-1, GHG emissions from the broadcasting (BC) method were significantly higher than those from the transplanting (TP) method. Conclusion Therefore, the TP method is a better sowing technique than the BC method for reducing GHG emissions without reducing grain yield.

Which EU Country Contributes Most to GHG Emissions in the LULUCF Sector Relative to Population and GDP?

Abstract In pursuit of climate neutrality, EU nations must collectively address the problem of greenhouse gas (GHG) emissions and air pollutants, which necessitates equitable economic strategies. However, the heterogeneous economic, social, and geographical profiles present hurdles in enacting a cohesive policy framework and realizing shared goals. Land use, land use change and forestry (LULUCF) sector play a crucial role in achieving the EU 2050 climate neutrality goal, as LULUCF is both a source and a sink for GHG emissions, it provides products like wood and biomass that help to reduce emissions in other sectors. This paper aims to compare GHG emissions of different EU countries by using targeted indicators related to per capita and to GDP per capita to enhance the analysis. The results reveal substantial differences in emissions in relation to population and GDP per capita between selected EU countries, even among countries with similar profiles, such as Estonia, Latvia, Lithuania. Notably, countries with lower GDP per capita and smaller population tend to have higher emission values, suggesting less efficiency in managing land use and forestry. The study highlights the need for multi-year data analysis to identify trends in emissions and removals within the LULUCF sector, considering the impacts of natural disasters and economic activities such as bark beetle outbreak or wood harvesting.

Study on the Effectiveness of Constructed Wetlands in Purifying Polluted Water from Rivers and Greenhouse Gas Emissions

In order to investigate the effect of different substrates of constructed wetlands on the purification of polluted water in rivers and their greenhouse gas emissions, this study designed three small-scale constructed wetland experimental systems with traditional gravel (CW-G), volcanic rock (CW-V) and biomass carbon (CW-B) as filler substrates to investigate the effect of different constructed wetland systems on the removal of COD and nitrogen pollutants and to further analyse their effect on greenhouse gas emissions. The results showed that the removal rates of organic matter in all three groups of constructed wetlands reached over 90%. and 49.29% to 58.71%, respectively, with CW-V and CW-B significantly improving the removal of NH4 + -N and NO3− -N compared to CW-G (P &lt; 0.05). A comparison of greenhouse gas emissions reveals that although CW-B resulted in the highest N2O emissions due to its better removal of NO3− -N, its share in nitrogen removal was still the smallest. In addition, the rapid consumption of organic matter in the influent water and the oxidation of some CH4 to CO2 resulted in no detectable CH4 in any of the three groups of constructed wetlands. The results of this study show that the differences in treatment effects and greenhouse gas emissions between the three types of substrate constructed wetlands are significant, and this study can provide some scientific reference for the construction and operation of wetlands for the purification of polluted water bodies in rivers.

Life cycle assessment of wind turbine blade recycling approaches in the United States

Most wind turbine blades reaching end-of-life are sent to landfill where embedded cost, energy, and materials are lost. To avoid landfilling future blades, a broad range of recycling and material recovery approaches have been proposed as solutions in the U.S., each with benefits, challenges, and varying levels of technical maturity. The approaches include 1) cement co-processing, 2) mechanical recycling, 3) pyrolysis, 4) microwave pyrolysis and 5) solvolysis. While these approaches are all capable of recovering various forms of materials for use in secondary markets, there are trade-offs between material circularity, reducing harmful environmental emissions, and cost-effectiveness for the U.S. market. Life cycle assessment (LCA) is a critical step needed to compare these trade-offs and determine where future research and development should be focused. As a result, some previous LCA has been performed on recycling approaches. However, attempts to quantify and compare greenhouse gas emissions across a broad range of technologies have been limited, particularly within the U.S. market where landfill availability and costs do not hinder disposing of wind blades. This work addresses this limitation by presenting a detailed comparison of LCA greenhouse gas emissions and material yields from a range of wind turbine blade recycling approaches in the U.S. The LCA presented in this work includes baseline results, as well as a variety of sensitivity and scenario analyses that look at the impact of process modelling uncertainty, future energy mixes, and other critical input parameters. Overall, results show that mechanical recycling and microwave pyrolysis have the lowest net greenhouse gas emissions. However, the value of mechanically recycled materials is highly uncertain, as mechanical recycling generates a mixed feedstock that may underperform compared to virgin materials. Cement co-processing has higher net emissions than mechanical recycling or microwave pyrolysis but does generate a value-added feedstock that offsets virgin material from mining for cement production. Other advanced thermal and chemical recycling methods such as pyrolysis and solvolysis have higher net emissions due to increased energy consumption but are also highly sensitive to thermal energy sources within the model.

Comparison of GHG emissions from annual crops in rotation on drained temperate agricultural peatland with production of reed canary grass in paludiculture using an LCA approach

Drained peat soils contribute significantly to global human-caused CO2 emissions and reducing peat degradation via rewetting is high on the political agenda. Ceasing agricultural activities on rewetted soils might lead to land owner resistance and high societal expenses to compensate farmers. Continued biomass production adapted for wet conditions on peat soils potentially minimizes these costs and helps supplying the growing demand for e.g. materials, fuels and feed. Here we used a life cycle assessment approach (cradle to farm gate) to investigate the greenhouse gas (GHG) emissions related to three cases by applying IPCC (Intergovernmental Panel on Climate Change) emission factors and specific site conditions at a bog and a fen site that represent widely distributed temperate peat soils. Besides soil emissions, upstream emissions from input, operational emissions and emission related to rewetting construction work were included. The analyzed systems were deeply drained cash cropping on agricultural bog (potatoes (Solanum tuberosum L.), spring barley (Hordeum vulgare L.) and oat (Avena sativa L.), permanent Reed canary grass (RCG) (Phalaris arundinacea L.) production on non-drained bog and permanent RCG production on shallow-drained fen. The annual mean water table depths (WTD) were −70, −38 (estimated) and −13 cm, respectively. Results showed estimated GHG emissions of 40.5, 26.1 and 20.6 Mg CO2eq ha−1, respectively, corresponding to a 35% GHG reduction for the non-drained bog case as compared to the drained bog case, despite that the obtained WTD due to ceased drainage did not adhere to the IPCC rewetting threshold of −30 cm. Emissions related to crop management represented 7, 14 and 19% of total emissions. In the RCG cultivation on fen case, the WTD were controlled primarily by the water table of the nearby stream and total GHG emissions were even lower as compared to the RCG production on the non-drained bog reflecting the difference in WTD. Rewetting projects need to include careful knowledge of the specific peat area to foresee the actual reduction potential.

Continuous Improvement of VIVA-Certified Wines: Analysis and Perspective of Greenhouse Gas Emissions

The agri-food sector is one of the major contributors of Greenhouse Gas (GHG) emissions responsible for global climate change. The suitability of world areas for viticulture is evolving due to climate change, with new challenges linked to the sustainability of production. Viticulture and the wine sector in general are, at the same time, impactful sectors associated with negative environmental externalities. The VIVA certification program is focused on the sustainability performance of the vine–wine supply chain in Italy. It comprehends four scientific indicators, called “Air”, “Water”, “Vineyard”, and “Territory”. The Air indicator expresses the impact that the production of a specific wine and / or the company activities have on climate change. This paper analyzes and compares GHG emissions of 45 wines certified VIVA 2.0 (or the subsequent 2.1 update). Results showed that the most impactful phase is the bottling phase (average values of 0.58 kg CO2-eq/bottle), which accounts for 41.1% of total emissions, followed by the industrial phase (about 19.9%). The total values of GHG emissions for each wine profile ranged between 0.81 and 2.52 kg CO2-eq/bottle. A coefficient of performances of GHG emissions was calculated to show the weak phase for each wine, a useful tool with a view to continuous improvement.

УГЛЕРОДНЫЕ ПОЛИГОНЫ КАК ИСТОЧНИК ДАННЫХ УГЛЕРОДНОГО СЛЕДА ЧЕЛОВЕЧЕСТВА

The carbon cycle plays an important role in the Earth’s ecosystem and it is crucial for understanding climate change. This article explores the concepts of carbon polygons and carbon farms as innovative approaches to reduce carbon emissions and promote sustainable development practices. These areas facilitate the development and adaptation of technologies for measuring carbon sequestration, soil agrochemical studies, and comparing greenhouse gas emissions and absorbers in different ecosystems. The establishment of carbon polygons in Russia, such as the “Carbon” project, allows for accurate measurements of carbon sequestration and testing of different carbon sequestration methods. On the other hand, carbon farming, which is seen as a further development, aims to maximise the uptake of carbon dioxide by terrestrial ecosystems. This approach involves the strategic introduction of highly effi cient technologies and the cultivation of plants that excel at carbon capture and storage. The success of carbon polygons and carbon farming depends on a variety of factors. International cooperation and knowledge exchange are critical to advancing research, developing standard methodologies and establishing a global system for measuring carbon sequestration. Key words: carbon dioxide accumulation, fi eld studies, carbon polygon, ecological footprint

Comparative LCA study of wood and mineral non-residential buildings in Germany and related substitution potential

The construction sector is a central source of greenhouse gas (GHG) emissions. Reducing environmental impacts along the life cycle of buildings is therefore an important target. Given recent innovations in low-energy buildings and energy supply systems with low climate impacts, additional reduction potential can mainly be found in mitigating GHG emissions in other life cycle stages. The focus of mitigation has thus shifted to emissions related to material input, and comparative life cycle analyses of buildings constructed with different material types are becoming increasingly relevant in guiding regulations to achieve emission reduction targets. This paper performs comparative life cycle assessments for 48 non-residential buildings, comparing GHG emissions according to the current European standardised calculation methods. A substitution potential is introduced to evaluate the advantage of using timber as a building material. Furthermore, a comparative method is presented for assessing the substitution potential on the building level. The results show that the substitution potential for the construction of the studied buildings ranges from 5 to 48%. Specific substitution potentials are differentiated between four subcategories of non-residential buildings. The lowest substitution potential was identified for agricultural buildings and the highest for office and administration buildings. Moreover, the current research shows that the specific materials, construction, the geometry and design all affect the substitution potential of a building. On the basis of these values, it is possible to make projections regarding GHG reduction potential in the construction sector on a national scale.

A Step toward a Sustainable Diet by Reducing Carbon Footprint: A Case Study in Iran

Introduction: Greenhouse gas (GHG) emissions have caused environmental effects. Food production is one of the sources of GHGs. This study aimed to suggest dietary scenarios for decreasing GHG emissions.&#x0D; Materials and Methods: GHG emissions in the target population of Urmia city, Northwest Iran, were investigated using a modeling approach. Three dietary scenarios were modeled and analyzed to evaluate and compare GHG emissions. The objectives and decision variables of the three scenarios included minimizing the carbon footprint and intake of food items, respectively. In the first scenario, the amount of energy intake was equal to baseline energy intake. The second scenario maintained the same energy intake constraint as the first scenario and made further alterations by considering the number of serving sizes suggested by the food pyramid for each food group. The third scenario was mostly based on this model by accounting for dietary reference intake for macronutrients, micronutrients, and energy.&#x0D; Results: There was about 72% and 55.67% reduction in carbon dioxide equivalent (CO2 eq) production in the first and second scenarios rather than the baseline diet of 4072.10 g CO2 eq, respectively. In the final scenario, the CO2 eq emissions were less than half of the baseline diet.&#x0D; Conclusion: The study showed that a healthy diet with a higher proportion of vegetables, fruit, legumes, nuts, and dairy, and a lower share of red and white meat, egg, grains, fat and oil, and sweets can reduce CO2 eq emissions.

Estimating & comparing greenhouse gas emissions for existing intramuscular COVID-19 vaccines and a novel thermostable oral vaccine.

BackgroundClimate impacts are rarely considered in health impact and economic assessments of public health programs. This study estimates the greenhouse gas (GHG) emissions averted by a novel oral SARS-CoV-2 (COVID-19) vaccine compared with four existing intramuscular vaccines: AstraZeneca's COVISHIELD®, Pfizer/BioNTech's COMIRNATY®, Moderna's mRNA-1273, and Johnson & Johnson's Ad26.COV2.S COVID-19 vaccine.MethodsWe estimated GHG emissions averted for five vaccine modalities across nine countries. GHG emissions averted were derived from differences in cold chain logistics, production of vaccine supplies, and medical waste disposal. Countryspecific data including population coverage and electricity production mix were included in GHG emissions calculations. Results are presented in averted GHG per vaccine course and country level based on modeled vaccination demand.FindingsPer course, an oral vaccine is estimated to avert between 0.007 and 0.024 kgCO2e compared with Johnson & Johnson, 0.013 to 0.048 kgCO2e compared with AstraZeneca, 0.23 to 0.108 kgCO2e compared with Moderna, and 0.134 to 0.466 kgCO2e compared with Pfizer/BioNTech. The total GHG averted varied across countries based upon predicted demand, mix of electrical production, and vaccination strategy with the largest emissions reductions projected for India and the United States.InterpretationOur results demonstrate large potential GHG emissions reductions from the use of oral vs. intramuscular vaccines for mass COVID-19 vaccination programs. Up to 82.25 million kgCO2e could be averted from utilization of an oral vaccine in the United States alone, which is equivalent to eliminating 17,700 automobiles from the road for one year.FundingFunding was provided by Vaxart, Inc. Vaxart, Inc. is currently developing an oral COVID-19 vaccine, the characteristics of which were utilized to define the thermostable oral vaccine discussed in this study. Apart from providing data on the characteristics of the oral vaccine under development, the funders had no influence over the study design, methods, statistical analyses, results, framing of results, decision to submit the manuscript for publication, or choice of journal.

Technical note: On comparing greenhouse gas emission metrics

Abstract. Many metrics for comparing greenhouse gas emissions can be expressed as an instantaneous global warming potential multiplied by the ratio of airborne fractions calculated in various ways. The forcing equivalent index (FEI) provides a specification for equal radiative forcing at all times at the expense of generally precluding point-by-point equivalence over time. The FEI can be expressed in terms of asymptotic airborne fractions for exponentially growing emissions. This provides a reference against which other metrics can be compared. Four other equivalence metrics are evaluated in terms of how closely they match the timescale dependence of FEI, with methane referenced to carbon dioxide used as an example. The 100-year global warming potential overestimates the long-term role of methane, while metrics based on rates of change overestimate the short-term contribution. A recently proposed metric based on differences between methane emissions 20 years apart provides a good compromise. Analysis of the timescale dependence of metrics expressed as Laplace transforms leads to an alternative metric that gives closer agreement with FEI at the expense of considering methane over longer time periods. The short-term behaviour, which is important when metrics are used for emissions trading, is illustrated with simple examples for the four metrics.

Promotion of full-scale constructed wetlands in the wine sector: Comparison of greenhouse gas emissions with activated sludge systems

The aim of this study was to quantify and compare greenhouse gas (GHG) (i.e. carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4)) emissions from two full-scale winery wastewater and sludge treatment systems (i.e. constructed wetlands (CWs) and activated sludge system) located in Galicia (Spain). GHG fluxes were measured using the static chamber method in combination with an on-site Fourier transform infrared spectroscopy (FTIR) gas analyser in the CWs system. These on-site innovative techniques proved to be very accurate and reliable. In the activated sludge treatment systems, the floating chamber method in combination with the FTIR gas analyser was used. Measurements were carried out during the vintage season, when winery wastewater has the highest flow and loads, and the rest of the year. Emission rates of CO2, N2O and CH4 in the CWs units (i.e. vertical flow, horizontal subsurface flow and sludge treatment wetlands) ranged from 1.35E+02 to 7.54E+04, 1.70E-01 to 3.09E+01 and − 3.05E+01 to 1.79E+03 mg m−2 day−1, respectively. In the case of the activated sludge units (i.e. reactor, secondary settler and sludge storage tank) emission rates of CO2, N2O and CH4 ranged from 1.56E+04 to 1.43E+05, 1.13E+01 to 4.75E+01 and 2.52E+01 to 1.01E+03 mg m−2 day−1, respectively. Seasonally, daily and instantaneous variability in emissions as well as spatial variability was found. Comparing CWs with the activated sludge system, surface emission rates were lower in the CWs system in both seasons considered. Results highlighted that CWs are suitable technologies that can help to reduce GHG emissions associated with winery wastewater treatment.

Nitrous Oxide and Methane Emissions from Beef Cattle Feedyard Pens Following Large Rainfall Events

HighlightsNitrous oxide and methane emissions were measured from a commercial beef feedyard following large rainfall events.Nitrous oxide emissions dropped below detection levels for ten days following a 77 mm rainfall event.Daily N2O and CH4 emissions followed a diel pattern, peaking at manure temperatures of 36°C to 38°C.Results will be used to refine empirical models for predicting GHG emissions from open-lot feedyards.Abstract. More than six million beef cattle are fed annually in feedyards on the semiarid Southern Great Plains (SGP). Manure deposited on the open-lot pen surfaces contributes to greenhouse gas (GHG) emissions. Nitrous oxide (N2O) and methane (CH4) are GHGs linked to climate change, and both have global warming potentials greater than carbon dioxide (CO2). Two sampling campaigns were conducted in 2019 to quantify N2O and CH4 emissions from open-lot pen surfaces. The occurrence of large, unforecast rainfall events during both campaigns provided an opportunity to compare GHG emissions from the dry manure before rainfall and from the wetted pen surface for one to two weeks following precipitation. Temporal variability was quantified by continuous sampling using six to eight automated flux chambers, a multiplexer system, and real-time analyzers. Spatial variability was quantified using a recirculating portable chamber on a 5 × 8 grid. Nitrous oxide emissions dropped below detection levels for ten days after the precipitation event. Nitrous oxide emissions were related to nitrification or other aerobic processes. Methane emissions dropped below detection levels for five days after the precipitation event and then increased to pre-rainfall levels by day 8. When present, N2O and CH4 emissions followed a diel pattern, with the highest emissions occurring during the afternoon when manure pack temperatures at the 25 mm depth were 36°C to 38°C and ambient temperatures were 31°C to 32°C. Average CH4 emissions from the feedyard pen surface were 96-fold lower than estimated enteric CH4 emissions. The results of this field research will be used to refine empirical models for predicting annual N2O and CH4 emissions from open-lot beef cattle feedyards on the semiarid SGP. Keywords: Beef cattle, Flux chamber, Greenhouse gas, Manure, Nitrous oxide, Rainfall.

Comparison of GHG emissions from circular and conventional building components

The concept of circular economy has been introduced as a strategy to reduce the greenhouse gas (GHG) emissions from buildings and mitigate climate change. Although many innovative circular solutions exist, the business model is challenged by a lack of environmental data on the circular solutions, and thus the potential benefits are not verifiable. The study assesses the embodied GHG emissions of five circular building elements/components. Circular solutions are compared with conventional solutions to ascertain whether the business model has the potential to reduce GHG emissions. The GHG emissions are quantified using life-cycle assessment (LCA) for five circular-economy and three conventional building elements/components. The environmental data show that circular building components have the potential to reduce GHG emissions. However, there is a risk of increasing the GHG emissions when compared with conventional solutions, emphasising the need for standardised environmental data. Lastly, the study identifies logistic, economic, technological and regulatory barriers that prevent complete implementation of circular economy. Practice relevance Standardised environmental data on building elements/components are needed to support decision-making at local and national levels. Uncertainties about waste from manufacture and transport in the production stage can affect the environmental potential to such an extent that the benefits from introducing circular economy are lost. One central barrier is identified that prevents complete implementation of the circular economy in buildings; the industry is not geared to support a steady supply of some circular building elements/components. In general, it is clear that the implementation of circular economy requires the identification of environmental, logistical, economic, technological and regulatory concerns.

ВЛИЯНИЕ ЭЛЕКТРОМОБИЛЕЙ НА ЭКОЛОГИЮ

Часто считается, что электромобили являются важным средством сокращения выбросов парниковых газов и энергопотребления в глобальном транспорте, особенно для автомобильного пассажирского транспорта.Целью данной статьи является изучение относительного использования энергии и выбросов парниковых газов электромобилей по сравнению с автомобилями с двигателем внутреннего сгорания. Сравнение энергоэффективности, а также сравнение выбросов парниковых газов были использованы в качестве методов в данной статье. Cравнения энергоэффективности осложняются противоречивыми методами, используемыми для первичных источников электроэнергии, таких как гидро, солнечная энергия или энергия ветра.В этой статье пересматривается степень, в которой электромобили могут эффективно решать проблемы глобального изменения климата и истощения запасов ископаемого топлива.Более того, в статье утверждается, что сравнение электромобилей и транспортных средств с двигателем внутреннего сгорания намного сложнее, чем общепризнанно. Неопределенности возникают как при использовании первичной энергии, так и при расчете выбросов парниковых газов.В целом, должен быть сделан вывод о том, что выгоды от использования электромобилей для энергии и парниковых газов меньше, чем обычно предполагается.Только когда во взаимосвязанных энергосистемах преобладают возобновляемые источники энергии, будет безопасно заявлять о превосходстве электромобилей.