Methane Gas Emissions Research Articles

Biogas production from the perspective of sustainable development

One of the basic aspects of sustainable development strategy involves investments in green technologies, including energy production from renewable sources. Biomass, special organic waste which belongs to “green sources” of energy can be used in the methane fermentation process of biogas production to generate heat and electricity.Biogas power plants have functioned in the Polish energy industry for many years now. On the basis of the data available from Central Statistical Office, in 2014 the ratio of biogas accounted for 7.6% of the structure of primary energy derived from renewable sources in the EU and 2.6% in Poland. An important consideration related to the production of biogas is associated with the applicability of waste resources derived from agricultural production and from the food industry, including pig slurry, slaughterhouse waste, brewing and distilling dregs as well as others. The operation of biogas plants provides considerable benefits to the environment, resulting from the controlled fermentation process and its application in the production of useful energy, as it can provide reduction of the emission of methane and other greenhouse gases. The aspects including the reduction of the volume of waste, environmental protection, fulfillment of the EU obligations and local energy security, form the reasons why communes in Poland should focus their attention on the use of biogas.This paper presents the results of SWOT analysis of biogas production in the context of sustainable development. The assessment of the aspects (strengths, weaknesses, opportunities and threats) and the intensity of their impact were undertaken on the basis of a point scale developed by the authors. The analysis shows that the process demonstrates a number of strengths, which can promote the implementation of positive changes in the environmental and social aspects undertaken on a local scale.

Grazing Intensity Impacts on Herbage Mass, Sward Structure, Greenhouse Gas Emissions, and Animal Performance: Analysis of Brachiaria Pastureland

A 7 year experiment (2008–2014) evaluated cattle grazing intensity (sward height) effects on herbage mass, forage quality, and greenhouse gas emissions in continuously stocked pastures containing the tropical ‘Marandu’ palisade grass (Brachiaria brizantha (Hochst. ex A. Rich) Stapf cv. Marandu). The experiment consisted of three sward height treatments (15, 25, and 35 cm) and six replicates. There were four periods each year during the rearing phase. Significant effects were found for herbage mass, proportions of leaf and stem, crude protein, neutral detergent fiber, acid detergent fiber, lignin, animal performance, enteric methane (CH4), and greenhouse gas (GHG) emissions from soils. When the canopy height increased from 15 to 35 cm, the herbage mass rose from 5.23 to 9.86 kg t ha−1, leaf percentage decreased, and stem percentage increased. Crude protein content averaged 14.2%, and neutral detergent fiber averaged 58%. Average daily gain averaged 0.67, 0.81, and 0.90 kg −1 head−1, while live weight gain ha–1 was 649, 530, and 439 kg for the 15, 25, and 35 cm treatments, respectively. The weather variables explained the GHG emissions, interannual herbage mass, and structure variations.

A Remote Sensing Technique to Upscale Methane Emission Flux in a Subtropical Peatland

AbstractQuantification of methane (CH4) gas emission from peat is critical to understand CH4 budget from natural wetlands under a climate warming scenario. Previous studies have focused on prediction and mapping of CH4 emission flux using process‐based models, while application of statistical‐empirical models for upscaling spatially sparse in situ measurements is scarce. In this study, we developed an empirical remote sensing upscaling approach to estimate CH4 emission flux in the Everglades using limited in situ point‐based CH4 emission flux measurements and Landsat data during 2013–2018. We spatially and temporally linked in situ data with Landsat surface reflectance based on temporally composite data sets and developed an object‐based machine learning framework to model and map CH4 emission flux. An ensemble analysis of two machine learning models, k‐Nearest Neighbor (k‐NN) and Support Vector Machine (SVM), shows that the upscaling approach is promising for predicting CH4 emission flux with a R2 of 0.65 and 0.87 based on a fivefold cross‐validation for a dry season and wet season estimation, respectively. We generated emission flux map products that successfully revealed the spatial and temporal heterogeneity of CH4 emission within the dominant freshwater marsh ecosystem in the Everglades. We conclude that Landsat is promising for upscaling and monitoring CH4 emission flux and reducing the uncertainty in emission estimates from wetlands.

MODEL OPTIMASI PENGELOLAAN SAMPAH DI TPA

The increase in waste generation is a major problem especially for urban areas such as Jakarta with insufficient landfill capacity and an inefficient and environmentally sound waste management system. To produce an optimal, integrated and sustainable landfill management strategy, an analysis of the TPST Bantargebang waste management system is then formulated towards optimization of sustainable landfill management in environmental, financial, and social aspects through a system dynamics intervention scenario model of the TPST Bantargebang waste management system. Based on the descriptive analysis carried out on the latest waste management, 3 main issues are known, namely, landfill capacity almost fully occupied, methane gas emissions increment, and the possibility waste pickers integration to increase scavenging productivity. Simulations were carried out with a system dynamics model for the 2018-2023 period with BAU conditions and an intervention scenario with a reduction in landfill waste and a reduction in waste flow. The results of the scenario are: landfill can still be utilized until 2023; methane gas emissions decreased by an average of 23,50%; the increase in the Scavenger Production Ratio to the Landfill Waste Rate reached 134,58%. As a consequence of the intervention and the addition of waste treatment activities in the TPST Bantargebang, the operational cost per ton has increased up to 309,62%. This study concludes that the scenario of incoming waste reduction and existing landfill waste reduction planned by Material Recovery Facility (MRF) construction with scavenger involvement, compost processing efficiency improvement, construction of Waste to Energy (WtE) facilities in the form of incinerator, landfill mining, and reprofiling simultaneously.

Effect of standing water levels on methane gas emission and yield performance of transplanted Aman rice (Oryza sativa L. cv. BRRI dhan51)

An experiment was conducted to investigate the effect of standing water levels on methane gas emission and yield of transplanted Aman rice (cv. BRRI dhan51) during July to December 2015 at medium low-lying area of Mohangonj upazila under Netrokona district. The experiment comprised five standing water levels on surface paddy soil viz., 5 cm, 10 cm, 15 cm, 20 cm and 25 cm. Methane (CH4) gas emission, yield components and yield of transplanted Aman rice were significantly affected by standing water levels on surface paddy soil. CH4 emission was gradually increased with rising standing water levels and remained static condition at 20-25 cm water level. The highest CH4 emission was observed at 20 cm standing water level and the lowest CH4 emission was recorded at 5 cm water level. The highest CH4 peak recorded at 85 days after transplanting (DAT). The highest CH4 flux (36.59 mg/m2/h) was observed in treatment 20 cm water level whereas the lowest CH4flux (21.17 mg/m2/h) was observed in 5 cm water level. Finally, the CH4 emission dropped at 108 DAT. On and average, the CH4 emission rate during rice cultivation followed 20 cm > 25 cm> 15 cm > 10 cm > 5 cm water level. Soil Eh gradually decreased with progress of time and plant growth and at 85 DAT highly reduced condition developed in all treatments. The maximum reduced condition was observed (-238.67 mV) in treatment 20 cm water level and minimum one (- 214.667 mV) was found in 5 cm water level. The highest grain (5260 kg ha-1) and straw (6725.0 kg ha-1) yields were obtained at 10 cm standing water level while the lowest grain (4191.6 kg ha-1) and straw (5050.0 kg ha-1) yields were recorded in 5 cm and 15 cm water level, respectively. It may be concluded that 10 cm standing water level is beneficial for transplant Aman rice (cv. BRRI dhan51) cultivation in low lying area in respect of grain yield and environmental issues.

Woodchip denitrification wall technology trialled in a shallow alluvial gravel aquifer

Woodchip denitrification walls are a tried and tested groundwater nitrate remediation concept in shallow sandy aquifer conditions. There are however no published case studies of them having been applied in heterogeneous, fast-flowing gravel aquifers. Such a pilot study is being made in a shallow alluvial gravel aquifer on the Canterbury Plains, New Zealand, as part of an assessment of whether denitrification walls represent a viable edge-of-field nitrate mitigation option for the New Zealand hydrological landscape. Hydrogeological conditions at the field study site were characterised using a suite of investigative methods, the results from which informed design and placement of an experimental woodchip denitrification wall that was installed in November 2018. The average specific flux in the target gravel aquifer is estimated at 2.7 m/d, and 3.1 m/d through the woodchip wall itself, owing to its hydraulic efficiency. These groundwater fluxes are significantly higher than conditions reported for pre-existing denitrification wall case-studies. Monitoring of the groundwater chemistry over the first year of the denitrification woodchip wall's operational life has shown how the woodchip initially leached labile dissolved organic carbon and created a redox plume in which methanogenic conditions existed. Even though dissolved organic carbon concentrations have restored to background levels, the woodchip wall remains effective at nitrate reduction. The measured nitrate removal rate of between 4.2 and 5.4 g N removed/m3 wall/d is higher than what had previously been predicted from controlled lab-scale studies of the wall media and ranks towards the higher end of published removal rates for denitrification walls. Whilst there is direct evidence that heterotrophic denitrification is contributing to the observed nitrate removal, on the basis of chemical indicators, it is assumed other reactive process, such as dissimilatory reduction to ammonia, anammox, and possibly nitrate-reducing Fe(II)-oxidising reduction reactions may also be contributing to the overall removal of nitrogen in the system. Indications are the woodchip wall is enhancing emission of methane gas, albeit at rates less than what is typically reported for constructed wetlands that are an alternative nitrate-remediation option. Emission of the more potent greenhouse gas nitrous oxide from the woodchip denitrification wall has so far been immeasurably low. Longer-term study of the woodchip denitrification wall is continuing.

Optimized inspection of upstream oil and gas methane emissions using airborne LiDAR surveillance

Methane is a short-lived climate pollutant responsible for approximately 20% of anthropogenic global warming, and reducing methane emissions from the oil and gas (O&G) industry is considered among the most urgent and actionable measures to mitigate climate change. Recent reports suggest a large fraction of upstream O&G methane emissions result from a small number of super-emitter facilities, emphasizing the value of novel methods that inspect O&G facilities with greater frequency than is practical using existing techniques. Here we describe an optimized method wherein O&G facilities are inspected for emissions at high frequency and high sensitivity using active laser (LiDAR) sensors mounted to aircraft. The method relies on a hierarchical clustering and routing procedure to establish optimal routes to be flown by aircraft departing from local airports and equipped with LiDAR methane sensors. Routes are optimized to inspect all well sites subject to emissions regulation in three O&G intensive regions: the Permian basin, the state of Colorado, and the state of Pennsylvania. While some cost estimates require additional field data, these modeling results suggest the optimized inspections can be performed with comparable effectiveness and up to a factor of six lower cost per inspection compared to current detection methods. The cost per inspection required to achieve equivalent emissions reduction depends on factors such as the weather conditions during inspection (which impacts the limit of detection and therefore the inspection frequency required to achieve equivalency) and the well density (which impacts the flying distance), and the advantage of this program over traditional inspection will be reduced under unfavorable conditions. These modeling results suggest that optimized routing may enable frequent inspection of upstream O&G facilities at large scale and potentially lead to a substantial decrease in both oilfield methane emissions and compliance costs borne by industry.

The natural gas sector needs to be mindful of its sustainability credentials

Despite substantial growth in demand for natural gas, building of infrastructure and prevailing low wholesale prices, some energy-industry stakeholders are now questioning the long-term sustainability of the natural gas industry. This is due, in part, to it being a fossil fuel with associated greenhouse gas emissions, and its very poor long-term historical track record regarding gas flaring and fugitive methane and other light-hydrocarbon gas emissions. However, major environmental concerns have also arisen regarding the development of unconventional natural gas resources using hydraulic fracture stimulation, its large environmental and community impacts, water usage and potential contamination and induced seismic activity leading to increased surface impacts. There are however a number of technological opportunities identified and available for deployment for a number of years that could enable the industry to improve its sustainability credentials. Seriously developing these opportunities could convince public opinion that the natural gas sector should be part of long-term plans to develop and maintain a near-zero emissions energy sector. Most of the identified opportunities are obvious, such as eliminating flaring, improving production efficiency by gaining a better understanding of sub-surface reservoirs and fluid movements, and reducing its surface footprints, carbon capture sequestration and utilization, and more collaboration with the renewables sector to build hybrid power and energy storage plants. It is imperative for the natural gas sector’s long-term future that it fully embraces these opportunities and makes them visibly contribute to more eco-friendly energy supply-chain developments. Cited as : Wood, D.A. The natural gas sector needs to be mindful of its sustainability credentials. Advances in Geo-Energy Research, 2020, 4(3): 229-232, doi: 10.46690/ager.2020.03.01

Association Between Diet Quality and Food Waste in South Florida

Abstract Objectives In 2015, the USDA/EPA set a goal of reducing food waste in 50% by 2030. This goal will not only lower U.S. methane gas emissions but also redirect food to millions of food insecure Americans. Little is known on food waste and its association with diet quality. Therefore, our objective was to explore the associations between diet quality and food waste. Methods This was a cross sectional study among adults ³18 years in south Florida who are the primary household food provider conducting a primary shopping event for the week. Participants were recruited outside of local grocery stores and asked to fill out a quick food waste survey. Pictures of the participants’ grocery receipts were taken to analyze diet quality using the Grocery Purchase Quality Index 2016 (GPQI-2016). The GPQI-2016 is based on the Healthy Eating Index (HEI)– 2010 and has 11 different components (each with a maximum score of 5 or 10) for a total score of 75. Correlations were used to determine the associations between diet quality and amount of food waste (Pearson) or reasons for food waste (Point-biserial). Results A total of 109 participants were recruited but 103 had complete data. Mean age was 44.6 ± 13.6 years, most were females (74%) and Hispanics (79%). Most usually grocery shop in a main event and then go back for smaller items (44%) once (36%) or twice (28%) a week. Mean diet quality score was 40.9 ± 9.64 out of 75 points and mean amount of food waste was 17.7 ± 19.9 handfuls. Most reported throwing away food mainly because it went bad (90%) or it was past it's due date (80%). Handfuls of bread/rice waste were significantly inversely correlated with diet quality (r = −2.60; p = 0.013). Also, we found a significant inverse correlation between diet quality and food thrown away because it had gone past it's use by date (r = −.196; p = 0.049). Conclusions A lower diet quality score was related to higher amount of bread/rice wasted and with throwing away foods that has past it's use date. These results could justify directing reducing food waste efforts in the community by educating individuals on purchasing frozen products or on proper storage to prolong shelf life, as well as on understanding the different dates placed on products by manufacturers. Funding Sources Internal funds from Florida International University.

Investigation of fugitive methane and gas collection efficiency in Halton landfill in Ontario, Canada.

Methane gas is one of the significant contributors to global warming. A large portion of methane emissions comes from landfills. Developing reliable measurement methods for methane emissions from landfill sites has become very important. In this paper, the surface emissions of methane gas are quantified using a portable probe having a flame ionization detector (FID), a method proven to be successful in landfill gas measurement. Surface methane emissions from two closed cells in the Halton landfill in Ontario, Canada, were measured using the FID method. By analyzing the emissions within the perimeter of the landfill, hotspots of gas leakage were identified. The closed cells in the Halton landfill are equipped with gas extraction system for flaring and energy recovery and a clay topsoil cover. Emission concentrations of fugitive methane were found to range from 0.1 to 63ppm. The largest emissions were detected in locations next to the leachate extraction manholes and malfunctioning gas extraction wells. The landfill gas balance showed that the landfill gas recovery efficiency was 44%, resulting in an average amount of fugitive methane from the landfill of 6124m3/day. The results of the study were used to determine the methane generation potential (Lo) for municipal solid waste to further calibrate the USEPA LandGEM model for Ontario landfills. The model was calibrated by actual methane emission measurement and recovery data. The calibrated Lo was found to be 70m3/t, which is lower than the estimated values in previous studies.

Application of the delphi method to new renewable energy assessments in power plants in North Sumatra province

AbstrakNew renewable energy assessment on power plants is one of the solutions that can be developed in order to increase the utilization of new renewable energy as a source of electrical energy in electricity generation and also to realize national energy security. Before conducting a new renewable energy assessment on a power plant, the steps that must be taken are determining the criteria and subcriteria. Determination of criteria and criteria for new renewable energy assessment at the power plant is carried out using the Delphi method. The Delphi method is a systematic and interactive method, which depends on a panel of independent experts. Delphi is based on the principle that estimates from expert structured groups are more accurate than those from unstructured or individual groups. In this study the Delphi questionnaire was distributed. Where the contents of the questionnaire are to determine the criteria and subcriteria in new renewable energy assessment at the power plant. The questionnaire was distributed to 3 respondents who were considered experts in their fields, namely new renewable energy at the power plant. The results of the distribution of the questionnaire are the criteria for evaluating new renewable energy used in the study consisting of 4 criteria namely technological aspects, economic aspects, environmental aspects, and social and political aspects developed into 16 subcriteria namely energy efficiency, security risk, energy production capacity, investment costs, operating and maintenance costs, financial risk, payback period, methane gas emissions. CO2 emissions, CO emissions, land use, ecosystem impacts, labor, political support / policy, human health impacts, social benefits.

Effects of feed intake on methane gas emission

Hydrid lams of Dorper x Native sheep weighted with 44.5-61.1 kg live were selected and divided into three experimental groups. Each experimental groups were fed by 50 percentages grass, 50 percentages of cereals and 50 percentages of mineral containing fees separately. Methane gas emission was measured from animal fed by pellets amounted 2.5 kg, 1.48 kg and 1.11 kg for first, second and third groups, respectively. During the study period, sheep extricated 6.65 liters, 5.05 liters and 1.78 liters of methane gas. The methane extraction was 24.1-71.8 percentage higher in first feeding groups compared to other two groups (P<0.01). The very strong positive correlation was found between he feed intake and methane gas emission. In other words, 67.0 percentages of methane gas emission were caused by the feed intake.
 Метан хийн ялгаралт тэжээлийн идэмжээс хамаарах нь
 Бид судалгаанд “Нутгийн х Дорпер” хонины F1 эрлийз, 44.5-61.1 кг амьдын жинтэй 15 хонийг сонгож туршилтын 3 бүлэгт (n=5) хувааж бүдүүн тэжээл 50, хүчит, эрдэс тэжээл 50 хувь бүхий жороор тэжээв. Туршлагын бүлгүүдэд хорголжин тэжээлийг хоногт I-р бүлэгт 2.5 кг, II-р бүлэгт 1.48 кг, III-р бүлэгт 1.11 кг-аар өгч метан болон нүүрсхүчлийн хийн ялгаралтыг судлав. Туршилтын хугацаанд I-р бүлгийн хонь 6.65 л, II-р бүлгийнх 5.05 л, III-р бүлгийнх 1.78 л метан хий ялгаруулсан ба I бүлэг бусад бүлгийнхээс 24.1-71.8 хувиар илүү ялгаруулсан байна (P<0.01). Метан хийн ялгаралт, тэжээлийн идэмж хоорондын хамаарлыг судлахад эерэг хамааралтай буюу 67.0 хувь нь идсэн тэжээлээс хамаарч байна.
 Түлхүүр үг: идэмж, метан хий, нүүрсхүчлийн хий

Mitigation of methane gas emissions in flooded paddy soil through the utilization of methanotrophs

The utilization of methanotrophs for reducing the global warming potential in a flooded paddy system is the progressive investigation in the recent. The field investigation was conducted in Tamil Nadu Rice Research Institute, Aduthurai. This study showed the effect of isolated methanotroph strain (MR15) on the reduction of methane emission and improvement in growth parameters and yield of paddy. The treatments included the diverse dosages of methanotroph consortium (0, 25, 50, 75 & 100%). The total seasonal methane emission varied between 1.96 and 5.04 kg ha−1 for the season of Kharif and 2.18 to 5.81 kg ha−1 for the season of Rabi owing to the footprint of methanotroph. Irrespective of treatments, the mean seasonal emission was more prominent during Rabi compared to the Kharif season. The dosage of methanotroph consortium significantly influenced not only seasonal methane emission but also the grain yield percentage, which increased over 100% Recommended Dose of Fertilizers (RDF). Application of 100% methanotroph consortium (i.e.6.25 kg ha−1) minimizes the methane emission by 60% with an increase in grain yield by 35% and lessens the usage of additional nutrients. Overall, this study showed a sign of atmospheric methane uptake with increase growth potential and yield of paddy cultivation using methanotroph consortium.

Economic feasibility of smart city power generation from biogas produced by food waste in Malaysia via techno-economic analysis

Malaysia is one of the fastest growing country towards modernization and technological advancement. The country population increased along with that with estimated population of 32.45 million in 2019 with annual growth rate of 1.6%. Rapid industrialization and urbanization lead to adverse effect on the environment from the increasing of waste generated. It is projected that Malaysia is expected to generate 49,670 tons of waste per day with annual increment of 5.19%. Current method of waste management is being dumped daily in unsanitary landfill. In Malaysia, 50% of waste generated is organic waste where disposal in landfill will generate methane gas emission. Total of 310,220 tons of methane gas was generated in peninsular in year 2010 and projected to reach 370,000 tons in 2020, an increase of 19.3% in 10 years. The government has planned to phase out landfills as waste-management method and to substitute with more energy efficient and environmental friendly method such as waste-to-energy and bio-digestion. To realize the government plan, economic analysis will be conducted on biogas production for electricity generation to be utilized in Malaysia smart city where one of the main criteria is sustainability and environmental friendly. This paper will give insight on economic feasibility of biogas production from municipal food waste for electricity generation to be utilized in existing and new township. This will include the estimation of capital cost required, unit production cost and payback period.

Repeated leak detection and repair surveys reduce methane emissions over scale of years

Reducing methane emissions from the oil and gas industry is a critical climate action policy tool in Canada and the US. Optical gas imaging-based leak detection and repair (LDAR) surveys are commonly used to address fugitive methane emissions or leaks. Despite widespread use, there is little empirical measurement of the effectiveness of LDAR programs at reducing long-term leakage, especially over the scale of months to years. In this study, we measure the effectiveness of LDAR surveys by quantifying emissions at 36 unconventional liquids-rich natural gas facilities in Alberta, Canada. A representative subset of these 36 facilities were visited twice by the same detection team: an initial survey and a post-repair re-survey occurring ∼0.5–2 years after the initial survey. Overall, total emissions reduced by 44% after one LDAR survey, combining a reduction in fugitive emissions of 22% and vented emissions by 47%. Furthermore, >90% of the leaks found in the initial survey were not emitting in the re-survey, suggesting high repair effectiveness. However, fugitive emissions reduced by only 22% because of new leaks that occurred between the surveys. This indicates a need for frequent, effective, and low-cost LDAR surveys to target new leaks. The large reduction in vent emissions is associated with potentially stochastic changes to tank-related emissions, which contributed ∼45% of all emissions. Our data suggest a key role for tank-specific abatement strategies as an effective way to reduce oil and gas methane emissions. Finally, mitigation policies will also benefit from more definitive classification of leaks and vents.

Ground food waste discharge to sewer enhances methane gas emission: A lab-scale investigation

Emission of sulfide and methane from sewerage system has been a major concern for a long time. Sewers are now facing emerging challenges, such as receiving food waste (FW) to relieve the burdens on solid waste treatment. However, the knowledge of the direct impact of FW addition on sulfide and methane production in and emission from sewers is still lacking. In this study, two lab-scale sewer reactors, one without and one with FW addition, were continuously operated to investigate the production of sulfide and methane and microbial communities arising from FW discharge to freshwater sewerage system. The 190-day long-term monitoring and the batch tests on days 69 and 124 suggest that the FW addition has little impact on sulfide production possibly due to the limited sulfate concentration (40 mg S/L) but enhanced methane production by up to 60%. Moreover, cryosection-fluorescence in situ hybridization (FISH) revealed that the FW addition significantly stimulated the accumulation of methanogenic archaea (MA) in sewer biofilms and altered the spatial distributions of sulfate-reducing bacteria (SRB) and MA. Moreover, the relative abundance of MA in biofilms with FW addition was higher than that without FW addition, whereas the relative abundance of SRB was similar. Metabolic pathway analysis for sulfidogenesis and methanogenesis indicates that sufficient substrates derived from the FW addition were biodegraded during fermentation to produce acetate and hydrogen, and consequently facilitate methanogenesis. These findings shed light on the impacts of changes in wastewater compositions (e.g., FW addition) on sulfide and methane production in the freshwater sewerage system for improved policy-making on sewer management.

Modeling Methane Emission of Wastewater Anaerobic Pond at Palm Oil Mill Using Radial Basis Function Neural Network

Plant-based industries such as palm oil mills will generate wastewater rich in organic matter. Palm oil mill effluent (POME) treatment in Indonesia is still dominant with conventional methods without the capture of methane. This system does not know the value of methane emitted into the atmosphere. Measurement and testing of biomethane from anaerobic ponds of palm oil mills are relatively difficult because gas material is rapidly changing. An alternative methodology that is accurate through modeling with a radial basis function neural network (RBFNN) with abiotic variable input. The aim of this research is to find out an anaerobic pond methane emission model of POME and simulation to find out the dynamics of methane emissions. Methane emission data is measured by a TGS2611 methane gas sensor CH4-meter system and using closed static chambers. A sampling of wastewater and methane gas was conducted in October-November 2018. The results showed that the methane gas emission model was obtained in the AP with RBFNN. The best RBFNN model had a 5-5-3 network architecture, spread 0.11 and error-goals 0.0005, R 0.940652 and MSE 0.003166. The reliability of RBFNN in determining models with non-linear field data variables was quite good, which was influenced by the number of data patterns, types and accuracy of the variables, network architecture, and the ANN model used. The simulation and prediction of methane emissions in the lowest-moderate-highest variable value scenario found that the COD-R and VS-R variables greatly affected the anaerobic pond WWTP emissions of multiple feeding systems. Even so, inlet wastewater temperature and rainfall variables had not significantly affected methane gas emissions, because the temperature was in a mesophilic range (30-40 oC) and the effect of rainfall would depend mainly on the high-low levels of organic matter (COD and VS).

Advective Fluxes in the Martian Regolith as a Mechanism Driving Methane and Other Trace Gas Emissions to the Atmosphere

AbstractAdvective fluxes influence methane and CO2 soil emissions into the atmosphere on Earth and may drive trace gas emissions in the Mars atmosphere. However, their relevance in the Martian regolith has not been evaluated to date. Our regolith transport simulations show that advective fluxes can be relevant under Martian conditions and may drive the methane abundance detected by Mars Science Laboratory. Trace gas emissions would be highest in regions where winds interact with topography. Emissions in these regions may be further enhanced by time‐varying pressure fields produced by diurnal thermal tides and atmospheric turbulence. Trace gases such as methane should be emitted or produced from the first layers of regolith, or quickly transported to this region from a deeper reservoir through fractured media.

Mitigation of methane gas emission in rice by drip irrigation

Background: Rice farming faces major challenges, including water limitation, drought and climate change in the current scenario of agriculture. Among the innovative water-saving techniques, drip irrigation is a forerunner, with maximized water-saving potential, increased grain yield and methane mitigation. Methods: A field experiment was conducted comprising four different drip irrigation practices: (i) sub-surface drip irrigation (SDI) with 1.0 litre per hour (lph) discharge rate emitters (DRE) (SDI+1.0 lph DRE) (ii) SDI+0.6 lph DRE, (iii) surface drip irrigation (DI) with 1.0 lph discharge rate emitters (DI+1.0 lph DRE), (iv) DI+0.6 lph DRE and were compared with (v) a conventional flood aerobic irrigation (considered conventional). Results: The estimated grain yield of rice was found to be 23.5%, 20.3%, and 15.1% higher under SDI+1.0 lph DRE, SDI+0.6 lph DRE and DI+1.0 lph DRE practices, respectively, than the conventional method. A water saving of 23.3% was also observed for all drip practices compared with conventional practices. Seasonal methane emission flux declined 78.0% in the drip methods over the conventional irrigation: better mitigation than previously reported values (alternate wetting and drying (47.5%) and system of rice intensification (29.0%) practices). Continuous soil aeration and enhanced soil methanotrophs (P<0.05) limit the peak methane emission in rice during the flowering phase in drip irrigation, which is reflected in the methane emission flux values. Consequently, the equivalent CO 2 (CO 2-eq) emissions and yield-scaled CO 2 eq-emission were found to be significantly lower in SDI (43.8% and 49.5%, respectively), and DI (25.1% and 26.7%, respectively) methods as compared with the conventional that ensures better methane mitigation and future climate-smart rice production systems. Conclusions: Drip irrigation could reduce the cumulative methane emission in aerobically grown rice. SDI + 1.0 lph DRE practice can be applied in areas with inadequate water availability and effective in reducing the CO 2-eq emission with better yield than conventional.

Mathematical Modeling of Landfill Gas (MSW)—Production of Gas with Methane Gas Content from Landfills (MSW)

The municipal solid waste (msw) is a source of landfill gas (msw)—with methane gas content. Preoccupations for landfill gas (msw) management date back since 1976 when, at a landfill (msw) in California (USA), it turned out practically that the landfill gas (msw) with methane gas content contains a gas with high caloric value that can be collected and used for economic purposes. The landfill gas (msw) contains methane gas (30% - 60% volume), carbon dioxide (45% - 50% volume), hydrogen sulfide and other gases. Methane gas, carbon dioxide, nitrous oxide and other gases are listed in Kyoto Protocol as high greenhouse gases. Their ecological-rational management is both a national and global preoccupation. In terms of greenhouse gases, especially methane gas, the landfill (msw) is held responsible for 3.5% - 5% of the total global greenhouse gases. Practically, the quantitative estimation of the methane gas in a municipal solid waste landfill can be done by measuring the landfill gas (msw) flow in an extraction-collection well. In Romania, a quantitative estimation relationship of methane gas from deposits (msw) was made, approaching the problem in a different way. This paper presents the calculation formula, the working algorithm, the municipal waste landfill equation and the NOMOGRAMA of a municipal solid waste landfill (msw). The NOMOGRAMA allows us to define the values for parameter -m- (number of months needed for an amount of municipal solid waste (msw) to degrade, starting with the year from which the landfill gas (msw) emission with methane gas content is calculated). Taking into account the environmental conditions for each location of municipal solid waste landfill, the calculation uses various indexes and approximations, while the fundamental parameter remains -m- defined by the NOMOGRAMA of the municipal solid waste landfill (msw). A municipal solid waste landfill (msw) is a conglomerate of waste with various biodegradation periods between 2 - 3 years and 5 - 10 - 30 years. Degradation of waste (msw) in to dissolved organic carbon will take place in a number of months defined -m- starting with the year from which the methane gas emission with the NOMOGRAMA of the municipal solid waste landfill (msw) is calculated. The -m- values for the year of the quantitative emission of methane gas can be also done analytically, which requires good experience in the ecologic-rational management of the municipal solid waste (msw).