Landfill Methane Emissions Research Articles

Methane emission dynamics from a Danish landfill: The effect of changes in barometric pressure.

This study investigates temporal variability on landfill methane (CH4) emissions from an old abandoned Danish landfill, caused by the rate of changes in barometric pressure. Two different emission quantification techniques, namely the dynamic tracer dispersion method (TDM) and the eddy covariance method (EC), were applied simultaneously and their results compared. The results showed a large spatial and temporal CH4 emission variation ranging from 0 to 100kgh-1 and 0 to 12μmol m-2 s-1, respectively. Landfill CH4 emissions dynamics were influenced by two environmental factors: the rate of change in barometric pressure (a strong negative correlation) and wind speed (a weak positive correlation). The relationship between CH4 emissions and the rate of change in barometric pressure was more complicated than a linear one, thereby making it difficult to estimate accurately annual CH4 emissions from a landfill based on discrete measurements. Furthermore, the results did not show any clear relationship between CH4 emissions and ambient temperature. Large seasonal variations were identified by the two methods, whereas no diurnal variability was observed throughout the investigated period. CH4 fluxes measured with the EC method were strongly correlated with emissions from the TDM method, even though no direct relationship could be established, due to the different sampling ranges of the two methods and the spatial heterogeneity of CH4 emissions.

Efficiency of gas collection systems at Danish landfills and implications for regulations

Globally, landfills are an important source of anthropogenic methane emissions. Regulations require landfill gas be managed to reduce emissions, and some landfills have therefore installed gas collection systems to recover energy and mitigate methane emissions. However, the efficiency of such systems is seldom evaluated. This paper presents the gas collection efficiencies of 23 Danish landfills and suggests how these values could be used to regulate landfill methane emissions in Denmark. Methane emissions from all sites were measured using the tracer gas dispersion method, and gas collection efficiencies were calculated using the ratio of the methane collection rate to the sum of the collection and emission (and oxidation) rates. Gas collection efficiencies ranged between 13 and 86% with an average of 50% – a value lower than for Swedish (58%), UK (64%) and US (63%) landfills. Possible reasons for the inefficiency of gas collection systems in Denmark include shallow gas collection pipes, leakage from installations (e.g. leachate wells, gas engines), low gas recovery due to minimal gas production or a lack of gas collection in active waste cells. It is suggested to use gas collection efficiency to regulate landfills and help them reach a particular methane mitigation goal. Gas collection efficiency that falls below the target mitigation rate would in turn trigger actions to reduce landfill methane emissions. At sites where the quality of the collected gas is too low to operate a gas engine, the installed gas collection system could be retrofitted to a biocover system designed for methane oxidation.

Estimation of methane emissions from municipal solid waste landfill in makassar city based on ipcc waste model

One of the greenhouse gases, which is the cause of climate change and global warming is methane gas (CH4). One of the most significant sources of methane that contributes to emissions globally is landfills (anthropogenic sources). Methane emissions from waste are the result of the anaerobic decomposition of organic matter in waste. The more garbage in the landfill without further treatment can lead to greater methane emissions. The site of this study was a municipal solid waste in Makassar city, named Tamangapa landfill, ±15 km from downtown Makassar city. The objectives of this study are to estimate methane emissions in the Tamangapa landfill and estimate methane emissions from the Tamangapa landfill over the next ten years using the 2006 IPCC Waste Model. The results showed that the waste generation in Makassar City, in 2016, was 0.449 kg/person/day with the composition of waste dominated by organic waste. The value of potential methane emissions at TPA Tamangapa Makassar in 2016 is 2.24 Gg/year and the projection in 2026 is 4.968 Gg/year. The mitigation and adaptation efforts that can be recommended are the socialization of 3R techniques (Reduce, Reuse, and Recycle) and construct a sanitary landfill in Makassar city following the mandate of Law No. 18 of 2008.

Induced Innovation in the Public Sector: Evidence from Landfill Methane Emissions Regulation

The concept of induced innovation suggests the ability for policy makers to design and implement economically efficient regulation, both limiting negative environmental impacts from corporate activity and providing firms opportunities to improve performance through innovation in regulatory response. While extant research has substantially addressed aspects of both induced innovation among regulated private sector firms and managerial innovation among public sector organizations, we know relatively little about the nature of innovation taken by public sector entities in response to environmental regulation. An improved understanding of induced innovation in the public sector is important because public organizations are increasingly subject to regulation, with implications for regulatory efficiency and local government viability. We address the problem by analyzing prevalence and determinants of induced innovation among both publicly and privately owned entities subject to regulation in a unique context: methane emissions from municipal solid waste landfills in the United States. We find that induced innovation is more prevalent among public than private organizations, whereas private organizations are more effective at implementing induced innovation projects. We also find unexpected effects of various institutional factors on innovation uptake. The study contributes to literatures on induced innovation and public sector innovation, provides insights to guide future research, and offers guidance for efficient regulatory design.

Carbon isotopic characterisation and oxidation of UK landfill methane emissions by atmospheric measurements.

Biological oxidation of methane in landfill cover material can be calculated from the carbon isotopic signature (δ13CCH4) of emitted CH4. Enhanced microbial consumption of methane in the aerobic portion of the landfill cover is indicated by a shift to heavier (less depleted) isotopic values in the residual methane emitted to air. This study was conducted at four landfill sites in southwest England. Measurement of CH4 using a mobile vehicle mounted instrument at the four sites was coupled with Flexfoil bag sampling of ambient air for high-precision isotope analysis. Gas well collection systems were sampled to estimate landfill oxidised proportion. Closed or active status, seasonal variation, cap stripping and site closure impact on landfill isotopic signature were also assessed. The δ13CCH4 values ranged from -60 to -54‰, with an average value of -57±2‰. Methane emissions from active cells are more depleted in 13C than closed sites. Methane oxidation, estimated from the isotope fractionation, ranged from 2.6 to 38.2%, with mean values of 9.5% for active and 16.2% for closed landfills, indicating that oxidised proportion is highly site specific.

Air permeability of biochar-amended clay cover

Biochar has a porous structure with high specific surface area and high adsorption. Moreover, it provides a suitable habitat for microorganisms that can reduce harmful gases. Adding biochar to a traditional landfill clay cover (i.e., biochar-amended clay cover) can increase soil porosity, improve soil air flow, and reduce landfill methane emissions which are an area of interest for many researchers. In the present research, the air permeability of biochar-clay is considered to be the main measure in evaluating the fluid-flow characteristic of the material. We discussed the influence of biochar content and particle size on air permeability of biochar-clay and its mechanism. The air permeability coefficient ka of biochar-clay mixture with different biochar content (0%, 5%, 10%, 15%, and 20%), dry densities (1.42 g/cm3, 1.56 g/cm3, and 1.65 g/cm3), and biochar particle size ranges ( 74 μm) were measured using a flexible wall air permeability testing device. Changes in soil pore structure were analyzed by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). The results show that when dry density was 1.42 g/cm3, the air permeability coefficient decreased as the biochar content increased. For biochar-clay mixture of 1.56 g/cm3 and 1.65 g/cm3, when the biochar content was 15%, the air permeability coefficient of biochar-clay mixture reached its lowest value. Comparing the air permeability coefficient of biochar-clay mixture with non-intersecting particle size groups of biochar, it was revealed that the permeability coefficient decreased as the biochar particle size decreased. Based on the pore structure of biochar-clay mixture with different biochar content and particle size, the influence biochar content and particle size on the air permeability was evident.

Site-specific determination of methane generation potential and estimation of landfill gas emissions from municipal solid waste landfill: a case study in Nam Binh Duong, Vietnam

Landfills are substantial anthropogenic sources of greenhouse gases such as methane (CH4), carbon dioxide (CO2), and non-methane volatile organic compounds (NMVOCs). This study reports a simple and efficient method for determining the environmental loads of landfill gases (LFG) emitted from the Nam Binh Duong landfill, Vietnam, by applying the LandGEM and the IPCC first-order decay models (FOD model). The environmental LFGs loads were quantified based on both the relevant parameters of the generation potential (L0) of 81 m3/Mg and the generation rate (k) of 0.355 year−1 of methane (CH4) as well as the average measurement value of CH4 (57% by volume of the LFGs) obtained throughout the on-site measurements of the investigated landfill (Scenario 1). Then, the quantified emission results of the LFGs were compared to those of the Clean Air Act (CAA) default mode of the model (Scenario 2). During the period from 2004 to 2144, the projected landfill methane emissions add up to 116,377 t of CH4 with an average of 825 t of CH4/year. The paired t test conducted to compare the gas emissions obtained from both scenarios demonstrated that the on-site parameters significantly affect the yield of the LFGs. The estimated total LFG, methane, CO2, and NMVOCs recovery potential can serve as supporting data for policy making on obtaining renewable energy from landfills and minimizing the environmental issues caused by LFGs emissions.

Reinforced Cuckoo Search based fugitive landfill methane emission estimation

A significant amount of fugitive methane emission is generated from Municipal Solid Waste which is quantifiable amount in the overall methane emission. Relatively several models are proposed to quantify the amount of emission in the landfill. These models are based on two methods 1. Using analytical emission 2. Measurements. In this paper, the estimation of source positions and the emissions rates of the methane emission sources are done along with the fusion of Gaussian dispersion model. The bio inspired optimization model namely reinforced cuckoo search optimization algorithm is imposed on the estimation of methane emission source positions and their emission rates. Two different case studies are carried out to prove the significance of the proposed model. Also, the Briggs model is employed to analyse the performance of proposed model when the choice of parameter differs from the actual meteorological condition. The results show the significance of proposed model both in single and multi-objective form. • Around the world, Methane (CH4) is the second most anthropogenic greenhouse gas that affects the climate and responsible for uninvited climatic change. • Methane emission from waste management is due to organic element decomposition and industrial landfills. • The Proposed Algorithm is used to estimate the position of methane emission sources and its emission rate with the help of Gaussian dispersion model. • In this paper, a bio inspired Reinforced Cuckoo Search algorithm is used to estimate the position of methane emission sources and its emission rate with the help of Gaussian dispersion model. • The results show the significance of proposed model and an extensive simulation is carried out with varied number of meteorological conditions.

Suitability assessment of dumpsite soil biocover to reduce methane emission from landfills under interactive influence of nutrients.

Biocovers are known for their role as key facilitator to reduce landfill methane (CH4) emission on improving microbial methane bio-oxidation. Methanotrophs existing in the aerobic zone of dumped wastes are the only known biological sinks for CH4 being emitted from the lower anaerobic section of landfill sites and even from the atmosphere. However, their efficacy remains under the influence of landfill environment and biocover characteristics. Therefore, the present study was executed to explore the suitability and efficacy of dumpsite soil as biocover to achieve enhanced methane bio-oxidation under the interactive influence of nutrients, carbon source, and environmental factors using statistical-mathematical models. The Placket-Burman design (PBD) was employed to identify the significant factors out of 07 tested factors having considerable impact on CH4 bio-oxidation. The normal plot and Student's t test of PBD indicated that ammonical nitrogen (NH4+-N), nitrate nitrogen (NO3--N), methane (CH4), and copper (Cu) concentration were found significant. A three-level Box-Behnken design (BBD) was further applied to optimize the significant factors identified from PBD. The BBD results revealed that interactive interaction of CH4 with NH4+-N and NO3--N affected the CH4 bio-oxidation significantly. The sequential statistical approach predicted that maximum CH4 bio-oxidation of 27.32 μg CH4 h-1 could be achieved with CH4 (35%), NO3--N (250 μg g-1), NH4+-N (25 μg g-1), and Cu (50 mg g-1) concentration. Conclusively, waste dumpsite soil could be a good alternative over conventional soil cover to improve CH4 bio-oxidation and lessen the emission of greenhouse gas from waste sector.

Influence of landfill methane emissions on environment – distribution modelling and assessment

Influence of landfill methane emissions on environment – distribution modelling and assessment

Comparing estimates of fugitive landfill methane emissions using inverse plume modeling obtained with Surface Emission Monitoring (SEM), Drone Emission Monitoring (DEM), and Downwind Plume Emission Monitoring (DWPEM)

ABSTRACTAs part of the global effort to quantify and manage anthropogenic greenhouse gas emissions, there is considerable interest in quantifying methane emissions in municipal solid waste landfills. A variety of analytical and experimental methods are currently in use for this task. In this paper, an optimization-based estimation method is employed to assess fugitive landfill methane emissions. The method combines inverse plume modeling with ambient air methane concentration measurements. Three different measurement approaches are tested and compared. The method is combined with surface emission monitoring (SEM), above ground drone emission monitoring (DEM), and downwind plume emission monitoring (DWPEM). The methodology is first trialed and validated using synthetic datasets in a hand-generated case study. A field study is also presented where SEM, DEM and DWPEM are tested and compared. Methane flux during two-days measurement campaign was estimated to be between 228 and 350 g/s depending on the type of measurements used. Compared to SEM, using unmanned aerial systems (UAS) allows for a rapid and comprehensive coverage of the site. However, as showed through this work, advancement of DEM-based methane sampling is governed by the advances that could be made in UAS-compatible measurement instrumentations. Downwind plume emission monitoring led to a smaller estimated flux compared with SEM and DEM without information about positions of major leak points in the landfill. Even though, the method is simple and rapid for landfill methane screening. Finally, the optimization-based methodology originally developed for SEM, shows promising results when it is combined with the drone-based collected data and downwind concentration measurements. The studied cases also discovered the limitations of the studied sampling strategies which is exploited to identify improvement strategies and recommendations for a more efficient assessment of fugitive landfill methane emissions.Implications: Fugitive landfill methane emission estimation is tackled in the present study. An optimization-based method combined with inverse plume modeling is employed to treat data from surface emission monitoring, drone-based emission monitoring and downwind plume emission monitoring. The study helped revealing the advantages and the limitations of the studied sampling strategies. Recommendations for an efficient assessment of landfill methane emissions are formulated. The method trialed in this study for fugitive landfill methane emission could also be appropriate for rapid screening of analogous greenhouse gas emission hotspots.

A model for the accurate estimation of methane emissions in landfills

Landfills are one of the major sources of methane (CH 4 ) emissions. Prediction of CH4 emissions from landfills is important in estimating power generation potential and greenhouse gas (GHG) emissions from landfills. The most widely used landfill gas (LFG) models developed based on the first order decay (FOD) reaction do not take into account changing waste composition and landfill site conditions in methane estimations. The aim of this study was therefore to develop a LFG model for estimation of methane emissions from landfills in Lagos metropolis. Field investigations were carried out to determine waste composition, waste disposal rates and site conditions relevant for methane emissions estimation. Waste composition studies were conducted and waste fractions were divided into rapidly, moderately and slowly degrading. The output of the model was verified with the US EPA Landfill Gas Emission model (Land GEM). Results revealed maximum CH 4 emissions estimated occurred at the end of landfill’s closure. Methane generation potential (𝑳𝒐) and methane generation rate (𝒌) parameters were dependent on waste composition and site conditions. Model verification also showed methane emissions peaked at the end of landfill’s closure for both models and variation in modelling parameters by Land GEM model resulted in significant change in methane emissions. Keywords : Methane emissions, Landfills, Municipal solid waste, landfill gas, Land GEM model

Validation and error assessment of the mobile tracer gas dispersion method for measurement of fugitive emissions from area sources

A controlled release test was carried out to assess the accuracy of the tracer gas dispersion method, which is used to measure whole-site landfill methane (CH4) emissions as well as fugitive emissions from other area sources. Two teams performed measurements using analytical instruments installed in two vehicles, to measure downwind concentrations of target (CH4) and tracer gases at distances of 1.2–3.5 km from the release locations. The controlled target gas release rates were either 5.3 or 10.9 kg CH4 h−1, and target and tracer gases were released at distances between 12 m and 140 m from each other. Five measurement campaigns were performed, where the plume was traversed between 2 and 31 times. The measured target gas emissions agreed well with the controlled releases, with rate differences no greater than 1.1 kg CH4 h−1 for Team A and 1.0 kg CH4 h−1 for Team B when quantifying a controlled release of 10.9 kg CH4 h−1. This corresponds to a maximum error of ±10%. A larger error of up to 18% was seen in the campaign with a lower target gas release rate (5.3 kg CH4 h−1). Using a cross plume integration method to calculate tracer gas to target gas ratios provided the most accurate results (lowest error), whereas larger errors (up to 49%) were observed when using other calculation methods. By establishment of an error budget and comparison with the measured error based on the release test, it could be concluded that following best practice when performing measurements, the overall error of a tracer gas dispersion measurement is very likely to be less than 20%.

Assessment of a landfill methane emission screening method using an unmanned aerial vehicle mounted thermal infrared camera – A field study

An unmanned aerial vehicle (UAV)-mounted thermal infrared (TIR) camera’s ability to delineate landfill gas (LFG) emission hotspots was evaluated in a field test at two Danish landfills (Hedeland landfill and Audebo landfill). At both sites, a test area of 100 m2 was established and divided into about 100 measuring points. The relationship between LFG emissions and soil surface temperatures were investigated through four to five measuring campaigns, in order to cover different atmospheric conditions along with increasing, decreasing and stable barometric pressure. For each measuring campaign, a TIR image of the test area was obtained followed by the measurement of methane (CH4) and carbon dioxide (CO2) emissions at each measuring point, using a static flux chamber. At the same time, soil temperatures measured on the surface, at 5 cm and 10 cm depths, were registered. At the Hedeland landfill, no relationship was found between LFG emissions and surface temperatures. In addition, CH4 emissions were very limited, on average 0.92–4.52 g CH4 m−2 d−1, and only measureable on the two days with decreasing barometric pressure. TIR images from Hedeland did not show any significant temperature differences in the test area. At the Audebo landfill, an area with slightly higher surface temperatures was found in the TIR images, and the same pattern with slightly higher temperatures was found at a depth of 10 cm. The main LFG emissions were found in the area with the higher surface temperatures. LFG emissions at Audebo were influenced significantly by changes in barometric pressure, and the average CH4 emissions varied between 111 g m−2 d−1 and 314 g m−2 d−1, depending on whether the barometric pressure gradient had increased or decreased, respectively. The temperature differences observed in the TIR images from both landfills were limited to between 0.7 °C and 1.2 °C. The minimum observable CH4 emission for the TIR camera to identify an emission hotspot was 150 g CH4 m−2 d−1 from an area of more than 1 m2.

Life-cycle carbon budget of China's harvested wood products in 1900–2015

Harvested wood products (HWP) are essential carbon pool of the forestry sector and can play an important role in climate change mitigation. Since the 10th Conference of Parties to the United Nations Framework Conversion on Climate Change in 2009, HWP have been required to be included in forest management as an additional carbon pool in national greenhouse gas (GHG) inventory reports. China is the largest consumer of end-use HWP and the largest importer of primary HWP in the world. Thus, the carbon stocks and emissions of China's HWP must be accurately assessed for evaluating their contribution to the climate change mitigation potential of global HWP. We developed an analysis framework by using Stock-Change Approach to estimate China's HWP carbon stocks/emissions from a life-cycle perspective, which covers three HWP life-cycle stages, namely, manufacture, end use, and end-of-life disposal. Using this framework, we produced the first-ever life-cycle carbon budget for HWP consumed by China in the period 1900–2015, based on a comprehensive analysis of China-specific data. From 1900 to 2015, total wood fiber input to the HWP carbon system in China was estimated to be 8049 teragrams of carbon dioxide-equivalent (Tg CO2-eq). Of the total wood fiber input, discarded mill residue, in-use HWP, and HWP disposed of at solid waste disposal sites retained 513, 3284, and 659 Tg CO2-eq of carbon, respectively, with the remaining 3591 Tg CO2-eq of wood carbon released back to the atmosphere. Of the total emission, combustion and decomposition of mill residue, burning of fuelwood, and combustion and decomposition of retired HWP accounted for 36.5%, 24.6%, and 38.9%, respectively. Landfill methane emissions were estimated to be 780 Tg CO2-eq after considering the global warming potential of this greenhouse gas. The net HWP carbon stocks, the sum of the carbon retained by discarded mill residue and the carbon stocks of HWP in use and in landfills, minus landfill methane emissions, increased from 297 Tg CO2-eq in 1950 to 4456 Tg CO2-eq in 2015.

Quantity, Components, and Value of Waste Materials Landfilled in the United States

SummaryThe current system of production and consumption needs end‐of‐life disposal to function, but the linkage between upstream production‐consumption with the downstream landfill as terminus is, at best, a tenuous, one‐way relationship, suggesting a partial system failure. A starting point to fix this link is to confront, systematically, the messy “black box” that is mixed waste landfilling, interrogate its contents locally, and determine a baseline that can be used to scale up results. Here, we develop a detailed model characterizing landfilled municipal solid waste (MSW) in the United States across the dimensions of material quantity, quality, location, and time. The model triangulates measurements spanning 1,161 landfills (representing up to 95% of landfilled MSW) and 15,169 solid waste samples collected and analyzed at 222 sites across the United States. We confirm that landfilled quantities of paper (63 million megagrams [Mg]), food waste (35 million Mg), plastic (32 million Mg, textiles (10 million Mg), and electronic waste (3.5 million Mg) are far larger than computed by previous top‐down U.S. government estimates. We estimate the cost of MSW landfill disposal in 2015 (10.7 billion U.S. dollars [USD]) and gross lost commodity value of recyclable material (1.4 billion USD). Further, we estimate landfill methane emissions to be up to 14% greater (mass basis) than the 2015 U.S. inventory. By principally relying on measurements of waste quantity and type that are recorded annually, the model can inform more effective, targeted interventions to divert waste materials from landfill disposal, improve local, regional, and national emission estimates, enhance dissipative loss estimates in material flow analyses, and illuminate the dynamics linking material, energy, and economic dimensions to production, consumption, and disposal cycles.

AERMOD as a Gaussian dispersion model for planning tracer gas dispersion tests for landfill methane emission quantification

The measurement of methane emissions from landfills is important to the understanding of landfills’ contribution to greenhouse gas emissions. The Tracer Dispersion Method (TDM) is becoming widely accepted as a technique, which allows landfill emissions to be quantified accurately provided that measurements are taken where the plumes of a released tracer-gas and landfill-gas are well-mixed. However, the distance at which full mixing of the gases occurs is generally unknown prior to any experimental campaign.To overcome this problem the present paper demonstrates that, for any specific TDM application, a simple Gaussian dispersion model (AERMOD) can be run beforehand to help determine the distance from the source at which full mixing conditions occur, and the likely associated measurement errors. An AERMOD model was created to simulate a series of TDM trials carried out at a UK landfill, and was benchmarked against the experimental data obtained. The model was used to investigate the impact of different factors (e.g. tracer cylinder placements, wind directions, atmospheric stability parameters) on TDM results to identify appropriate experimental set ups for different conditions.The contribution of incomplete vertical mixing of tracer and landfill gas on TDM measurement error was explored using the model. It was observed that full mixing conditions at ground level do not imply full mixing over the entire plume height. However, when full mixing conditions were satisfied at ground level, then the error introduced by variations in mixing higher up were always less than 10%.

Atmospheric modeling to assess wind dependence in tracer dilution method measurements of landfill methane emissions

The short-term temporal variability of landfill methane emissions is not well understood due to uncertainty in measurement methods. Significant variability is seen over short-term measurement campaigns with the tracer dilution method (TDM), but this variability may be due in part to measurement error rather than fluctuations in the actual landfill emissions. In this study, landfill methane emissions and TDM−measured emissions are simulated over a real landfill in Delaware, USA using the Weather Research and Forecasting model (WRF) for two emissions scenarios. In the steady emissions scenario, a constant landfill emissions rate is prescribed at each model grid point on the surface of the landfill. In the unsteady emissions scenario, emissions are calculated at each time step as a function of the local surface wind speed, resulting in variable emissions over each 1.5-h measurement period. The simulation output is used to assess the standard deviation and percent error of the TDM−measured emissions. Eight measurement periods are simulated over two different days to look at different conditions. Results show that standard deviation of the TDM- measured emissions does not increase significantly from the steady emissions simulations to the unsteady emissions scenarios, indicating that the TDM may have inherent errors in its prediction of emissions fluctuations. Results also show that TDM error does not increase significantly from the steady to the unsteady emissions simulations. This indicates that introducing variability to the landfill emissions does not increase errors in the TDM at this site. Across all simulations, TDM errors range from −15% to 43%, consistent with the range of errors seen in previous TDM studies. Simulations indicate diurnal variations of methane emissions when wind effects are significant, which may be important when developing daily and annual emissions estimates from limited field data.

Fugitive halocarbon emissions from working face of municipal solid waste landfills in China

Halocarbons are important anthropogenic greenhouse gases (GHGs) due to their long lifetime and large characteristic factors. The present study for the first time assessed the global warming potential (GWP) of fugitive halocarbon emissions from the working face of landfills in China. The national emissions of five major halocarbons (CFC-11, CFC-113, CH2Cl2, CHCl3 and CCl4) from the working face of municipal solid waste landfills in China were provided through observation-based estimations. The fluxes of halocarbons from working face of landfills were observed much higher than covered cells in landfills hence representing the hot spots of landfill emissions. The annual emissions of the halocarbons from landfills in China were 0.02–15.6kt·y−1, and their GWPs were 128–60,948kt-CO2-eq·y−1 based on their characteristic factors on a 100-year horizon. CFC-113 was the dominant species owing to its highest releasing rate (i.e. 15.4±19.1g·t−1) and largest characteristic factor, resulting in a GWP up to 4036±4855kt-CO2-eq·y−1. The annual emissions of CFC-113 from landfills (i.e. 0.61kt·y−1) made up ∼76% of the total national CFC-113 emissions. The GWPs of halocarbons were estimated ∼14.4% of landfill methane emissions. Therefore, fugitive halocarbons emissions from working face are significant sources of GHGs in landfill sites in China, although they comprise a small fraction of total landfill gases.

Is MSW derived DME a viable clean cooking fuel in Kolkata, India?

Abstract An important energy poverty reduction initiative in India is aimed at replacing the use of solid cooking fuels with cleaner burning Liquefied Petroleum Gas (LPG). Projections suggest however that India will become increasingly dependent on LPG imports, the cost of which is strongly linked to the prevailing oil price and associated volatility. Dimethyl ether (DME) is a synthetic fuel which may be manufactured from domestically available carbonaceous feedstocks, and is compatible with blending with LPG. Very large quantities of Municipal Solid Waste (MSW) are generated in India's metropolitan cities, 90% of which is disposed of onto unsanitary landfills, creating major environmental and health concerns. This article investigates the techno-economic merits of reducing these impacts by using a portion of the MSW generated in Kolkata (in the form of a Refuse Derived Fuel (RDF)) to produce DME. Results suggest that the production of DME from a 50:50 blend of locally available coal and RDF (comprising 10% of the MSW placed at Kolkata's main landfill) will enable the supply of a clean cooking fuel to approximately 15% of Kolkata's population, and become cost competitive with imported LPG at an Indian basket oil price of $130 per barrel. Results also suggest that, at this blend ratio, the fossil fuel derived greenhouse gas emissions at the DME production plant will be more than offset by landfill methane emissions avoided using the RDF.