The Experts below are selected from a list of 51285 Experts worldwide ranked by ideXlab platform
Zucong Cai - One of the best experts on this subject based on the ideXlab platform.
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Leachate treatment in Landfills is a significant N2O source
Science of The Total Environment, 2017Co-Authors: Xiaojun Wang, Mingsheng Jia, Chengliang Zhang, Shaohua Chen, Zucong CaiAbstract:Abstract The importance of methane (CH4) emissions from Landfills has been extensively documented, while the nitrous oxide (N2O) emissions from Landfills are considered negligible. In this study, three Landfills were selected to measure CH4 and N2O emissions using the static chamber method. Dongbu (DB) and Dongfu (DF) Landfills, both located in Xiamen city, Fujian Province, were classified as sanitary. The former started to receive solid waste from Xiamen city in 2009, and the latter was closed in 2009. Nanjing (NJ) landfill, located in Nanjing county, Fujian Province, was classified as managed. Results showed that for the landfill reservoirs, CH4 emissions were significant, while N2O emissions occurred mainly in operating areas (on average, 16.3 and 19.0 mg N2O m− 2 h− 1 for DB and NJ Landfills, respectively) and made a negligible contribution to the total greenhouse gas emissions in term of CO2 equivalent. However, significant N2O emissions were observed in the leachate treatment systems of sanitary Landfills and contributed 72.8% and 45.6% of total emissions in term of CO2 equivalent in DB and DF Landfills, respectively. The N2O emission factor (EF) of the leachate treatment systems was in the range of 8.9–11.9% of the removed nitrogen. The total N2O emissions from the leachate treatment systems of Landfills in Xiamen city were estimated to be as high as 8.55 g N2O-N capita− 1 yr− 1. These results indicated that N2O emissions from leachate treatment systems of sanitary Landfills were not negligible and should be included in national and/or local inventories of greenhouse gas emissions.
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Leachate treatment in Landfills is a significant N2O source
Science of The Total Environment, 2017Co-Authors: Xiaojun Wang, Mingsheng Jia, Chengliang Zhang, Shaohua Chen, Zucong CaiAbstract:Abstract The importance of methane (CH4) emissions from Landfills has been extensively documented, while the nitrous oxide (N2O) emissions from Landfills are considered negligible. In this study, three Landfills were selected to measure CH4 and N2O emissions using the static chamber method. Dongbu (DB) and Dongfu (DF) Landfills, both located in Xiamen city, Fujian Province, were classified as sanitary. The former started to receive solid waste from Xiamen city in 2009, and the latter was closed in 2009. Nanjing (NJ) landfill, located in Nanjing county, Fujian Province, was classified as managed. Results showed that for the landfill reservoirs, CH4 emissions were significant, while N2O emissions occurred mainly in operating areas (on average, 16.3 and 19.0 mg N2O m− 2 h− 1 for DB and NJ Landfills, respectively) and made a negligible contribution to the total greenhouse gas emissions in term of CO2 equivalent. However, significant N2O emissions were observed in the leachate treatment systems of sanitary Landfills and contributed 72.8% and 45.6% of total emissions in term of CO2 equivalent in DB and DF Landfills, respectively. The N2O emission factor (EF) of the leachate treatment systems was in the range of 8.9–11.9% of the removed nitrogen. The total N2O emissions from the leachate treatment systems of Landfills in Xiamen city were estimated to be as high as 8.55 g N2O-N capita− 1 yr− 1. These results indicated that N2O emissions from leachate treatment systems of sanitary Landfills were not negligible and should be included in national and/or local inventories of greenhouse gas emissions.
Xiaojun Wang - One of the best experts on this subject based on the ideXlab platform.
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Leachate treatment in Landfills is a significant N2O source
Science of The Total Environment, 2017Co-Authors: Xiaojun Wang, Mingsheng Jia, Chengliang Zhang, Shaohua Chen, Zucong CaiAbstract:Abstract The importance of methane (CH4) emissions from Landfills has been extensively documented, while the nitrous oxide (N2O) emissions from Landfills are considered negligible. In this study, three Landfills were selected to measure CH4 and N2O emissions using the static chamber method. Dongbu (DB) and Dongfu (DF) Landfills, both located in Xiamen city, Fujian Province, were classified as sanitary. The former started to receive solid waste from Xiamen city in 2009, and the latter was closed in 2009. Nanjing (NJ) landfill, located in Nanjing county, Fujian Province, was classified as managed. Results showed that for the landfill reservoirs, CH4 emissions were significant, while N2O emissions occurred mainly in operating areas (on average, 16.3 and 19.0 mg N2O m− 2 h− 1 for DB and NJ Landfills, respectively) and made a negligible contribution to the total greenhouse gas emissions in term of CO2 equivalent. However, significant N2O emissions were observed in the leachate treatment systems of sanitary Landfills and contributed 72.8% and 45.6% of total emissions in term of CO2 equivalent in DB and DF Landfills, respectively. The N2O emission factor (EF) of the leachate treatment systems was in the range of 8.9–11.9% of the removed nitrogen. The total N2O emissions from the leachate treatment systems of Landfills in Xiamen city were estimated to be as high as 8.55 g N2O-N capita− 1 yr− 1. These results indicated that N2O emissions from leachate treatment systems of sanitary Landfills were not negligible and should be included in national and/or local inventories of greenhouse gas emissions.
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Leachate treatment in Landfills is a significant N2O source
Science of The Total Environment, 2017Co-Authors: Xiaojun Wang, Mingsheng Jia, Chengliang Zhang, Shaohua Chen, Zucong CaiAbstract:Abstract The importance of methane (CH4) emissions from Landfills has been extensively documented, while the nitrous oxide (N2O) emissions from Landfills are considered negligible. In this study, three Landfills were selected to measure CH4 and N2O emissions using the static chamber method. Dongbu (DB) and Dongfu (DF) Landfills, both located in Xiamen city, Fujian Province, were classified as sanitary. The former started to receive solid waste from Xiamen city in 2009, and the latter was closed in 2009. Nanjing (NJ) landfill, located in Nanjing county, Fujian Province, was classified as managed. Results showed that for the landfill reservoirs, CH4 emissions were significant, while N2O emissions occurred mainly in operating areas (on average, 16.3 and 19.0 mg N2O m− 2 h− 1 for DB and NJ Landfills, respectively) and made a negligible contribution to the total greenhouse gas emissions in term of CO2 equivalent. However, significant N2O emissions were observed in the leachate treatment systems of sanitary Landfills and contributed 72.8% and 45.6% of total emissions in term of CO2 equivalent in DB and DF Landfills, respectively. The N2O emission factor (EF) of the leachate treatment systems was in the range of 8.9–11.9% of the removed nitrogen. The total N2O emissions from the leachate treatment systems of Landfills in Xiamen city were estimated to be as high as 8.55 g N2O-N capita− 1 yr− 1. These results indicated that N2O emissions from leachate treatment systems of sanitary Landfills were not negligible and should be included in national and/or local inventories of greenhouse gas emissions.
Charlotte Scheutz - One of the best experts on this subject based on the ideXlab platform.
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Regulating Landfills using measured methane emissions: An English perspective
Waste Management, 2018Co-Authors: Mark Bourn, Fabrizio Innocenti, R.a. Robinson, Charlotte ScheutzAbstract:Abstract Methane emissions from Landfills are an important source of greenhouse gases in the UK and worldwide. This paper considers how measurements of methane emissions could be used to regulate Landfills in England in order to reduce the contribution of landfilling to climate change. The paper presents the results of a number of UK studies undertaken to quantify methane emissions from Landfills. The methods used have included the DIAL (Differential Absorption Lidar) technique and a tracer gas dispersion method. A method based on aerial measurements has been developed. Methane emission rates were measured at 15 biodegradable waste Landfills. All of the Landfills where measurements took place had an active landfill gas extraction system. A methane collection index (MCI) is calculated for each landfill using the ratio of the methane collection rate to the sum of the collection and emission rates. The values of the index in the campaigns reported here ranged from 0.28 to 0.90. The modern operational Landfills surveyed achieved MCI values with a much narrower range of between 0.64 and 0.90 with an average of 0.76. This has demonstrated that it is possible for these Landfills to collect a high proportion of the landfill gas. A proposed approach is presented for regulating Landfills using the measured MCI. This would involve an annual measurement campaign to quantify the methane emissions and the use of the data provided by these surveys to develop an achievable but challenging MCI limit. A limit value of 0.75 for the MCI is used to illustrate the approach. An MCI that falls below the limit would trigger actions to reduce the methane emissions from the landfill.
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quantification of methane emissions from 15 danish Landfills using the mobile tracer dispersion method
Waste Management, 2015Co-Authors: Jacob Monster, Jerker Samuelsson, Peter Kjeldsen, Charlotte ScheutzAbstract:Highlights: • Quantification of whole landfill site methane emission at 15 Landfills. • Multiple on-site source identification and quantification. • Quantified methane emission from shredder waste and composting. • Large difference between measured and reported methane emissions. - Abstract: Whole-site methane emissions from 15 Danish Landfills were assessed using a mobile tracer dispersion method with either Fourier transform infrared spectroscopy (FTIR), using nitrous oxide as a tracer gas, or cavity ring-down spectrometry (CRDS), using acetylene as a tracer gas. The Landfills were chosen to represent the different stages of the lifetime of a landfill, including open, active, and closed covered Landfills, as well as those with and without gas extraction for utilisation or flaring. Measurements also included Landfills with biocover for oxidizing any fugitive methane. Methane emission rates ranged from 2.6 to 60.8 kg h{sup −1}, corresponding to 0.7–13.2 g m{sup −2} d{sup −1}, with the largest emission rates per area coming from Landfills with malfunctioning gas extraction systems installed, and the smallest emission rates from Landfills closed decades ago and Landfills with an engineered biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41–81%. Landfills where shredder waste was deposited showed significant methane emissions,more » with the largest emission from newly deposited shredder waste. The average methane emission from the Landfills was 154 tons y{sup −1}. This average was obtained from a few measurement campaigns conducted at each of the 15 Landfills and extrapolating to annual emissions requires more measurements. Assuming that these Landfills are representative of the average Danish landfill, the total emission from Danish Landfills were calculated at 20,600 tons y{sup −1}, which is significantly lower than the 33,300 tons y{sup −1} estimated for the national greenhouse gas inventory for 2011.« less
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Tracer method to measure landfill gas emissions from leachate collection systems.
Waste Management, 2010Co-Authors: Anders Michael Fredenslund, Charlotte Scheutz, Peter KjeldsenAbstract:Abstract This paper describes a method developed for quantification of gas emissions from the leachate collection system at Landfills and present emission data measured at two Danish Landfills with no landfill gas collection systems in place: Fakse landfill and AV Miljo. Landfill top covers are often designed to prevent infiltration of water and thus are made from low permeable materials. At such sites a large part of the gas will often emit through other pathways such as the leachate collection system. These point releases of gaseous constituents from these locations cannot be measured using traditional flux chambers, which are often used to measure gas emissions from Landfills. Comparing tracer measurements of methane (CH 4 ) emissions from leachate systems at Fakse landfill and AV Miljo to measurements of total CH 4 emissions, it was found that approximately 47% (351 kg CH 4 d −1 ) and 27% (211 kg CH 4 d −1 ), respectively, of the CH 4 emitting from the sites occurred from the leachate collection systems. Emission rates observed from individual leachate collection wells at the two Landfills ranged from 0.1 to 76 kg CH 4 d −1 . A strong influence on emission rates caused by rise and fall in atmospheric pressure was observed when continuously measuring emission from a leachate well over a week. Emission of CH 4 was one to two orders of magnitude higher during periods of decreasing pressure compared to periods of increasing pressure.
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Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions
Waste Management & Research, 2009Co-Authors: Charlotte Scheutz, Alex De Visscher, Helene Hilger, Marion Huber-humer, Julia Gebert, Jean E Bogner, Peter Kjeldsen, Kurt A SpokasAbstract:Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and Landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials utilizing oxygen that diffuses into the cover layer from the atmosphere. The methane oxidation process, which is governed by several environmental factors, can be exploited in engineered systems developed for methane emission mitigation. Mathematical models that account for methane oxidation can be used to predict methane emissions from Landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed.
Krishna R Reddy - One of the best experts on this subject based on the ideXlab platform.
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Innovative Biogeochemical Cover to Mitigate Landfill Gas Emissions: Investigation of Controlling Parameters Based on Batch and Column Experiments
Environmental Processes, 2019Co-Authors: Jyoti K. Chetri, Krishna R Reddy, Dennis G. GrubbAbstract:Municipal solid waste (MSW) Landfills generate different gases mainly methane (CH_4) and carbon dioxide (CO_2) during the process of waste decomposition. Modern Landfills are provided with gas collection systems, however, significant amount of landfill gas (LFG) escapes into the atmosphere, making Landfills one of the largest anthropogenic sources of CH_4 and CO_2 emissions. Several researchers have investigated various alternative landfill cover systems, such as biocovers, in order to mitigate CH_4 transport across landfill covers by enhancing microbial CH_4 oxidation. In recent years, biochar as an organic amendment has shown promise in enhanced microbial oxidation due to its inert/stable chemical nature, high surface area, high internal porosity, and high moisture holding capacity. However, in all these efforts, little regard is given to the CO_2 that still escapes into the atmosphere in undesirable amounts. The current study introduces the concept of biogeochemical cover, which uses steel slag in conjunction with biochar-amended soil to mitigate fugitive emissions from a landfill. The current study compares the CO_2 sequestration potential of steel slag, mainly basic oxygen furnace (BOF) slag under various environmental conditions that may prevail in the landfill cover. BOF slag shows significant CO_2 sequestration potential under variable conditions including moisture, temperature, gas flow conditions, and BOF slag type and particle size. The results suggest that the use of BOF slag could be a cost effective and green solution to the problems of fugitive LFG emissions.
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Identifying Active Methanotrophs and Mitigation of CH 4 Emissions in Landfill Cover Soil
Proceedings of the 8th International Congress on Environmental Geotechnics Volume 2, 2018Co-Authors: Raksha K. Rai, Jyoti K. Chetri, Stefan J Green, Krishna R ReddyAbstract:In the USA, municipal solid waste (MSW) Landfills constitute one of the major anthropogenic sources of methane emissions. In the landfill cover soils employed at MSW Landfills, aerobic methane-oxidizing bacteria (MOB) convert CH4 to CO2, thereby partially mitigating the CH4 emissions to the atmosphere. In this study, culture-dependent and culture-independent techniques were employed to evaluate methane oxidation capacity and to characterize the microbial community in landfill cover soil. Microcosms with synthetic landfill gas headspace were used to measure potential methane oxidation rates in landfill cover soil and in methanotrophs-enriched microbial consortia. The results demonstrate that the enriched landfill cover soil supported the growth of a diverse group of methanotrophic and methylotrophic microorganisms, and were dominated by Type I methanotrophs showing positive correlation with CH4 oxidation rates.
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Modeling Coupled Processes in Municipal Solid Waste Landfills: An Overview with Key Engineering Challenges
International Journal of Geosynthetics and Ground Engineering, 2017Co-Authors: Krishna R Reddy, Girish Kumar, Rajiv K. GiriAbstract:Disposal of municipal solid waste (MSW) in engineered Landfills is one of the most widely used waste management practices in the USA and worldwide. During its design life, landfilled MSW undergoes various complex mechanisms controlled by physical (hydraulic and mechanical), chemical, thermal, and biological processes and their interrelated behaviors. A thorough understanding of these coupled MSW interactions is critical in designing a stable, effective and well-operational landfill. However, to date, the current practices associated with mathematical modeling as well as long-term monitoring of landfill performance(s) are mostly empirical and limited to site-specific conditions. Moreover, they fail to substantially quantify the changes in the geotechnical properties of MSW that result from coupled processes, especially the highly uncertain biological processes that result in MSW degradation in Landfills. Furthermore, the spatially and temporally varied waste composition, heterogeneous and anisotropic nature of field MSW together with leachate and landfill gas production due to biodegradation results in atypical differential MSW settlement and, therefore, can adversely impact the long-term performance of Landfills. Over the years, numerous experimental studies, field studies and mathematical modeling studies that focus on these landfill processes have been performed to optimize MSW landfill performance. In this study, a critical review of the previous research efforts on coupled processes is provided to help landfill engineers understand, design and operate MSW Landfills safely and efficiently. Moreover, key research issues and challenges related to numerical modeling of landfilled MSW undergoing coupled processes are presented.
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landfill methane oxidation in soil and bio based cover systems a review
Reviews in Environmental Science and Bio\ technology, 2014Co-Authors: Bala Yamini Sadasivam, Krishna R ReddyAbstract:Mitigation of landfill gases has gained the utmost importance in recent years due to the increase in methane (CH4) emissions from Landfills worldwide. This, in turn, can contribute to global warming and climatic changes. The concept of microbially mediated methane oxidation in landfill covers by using methanotrophic microorganisms has been widely adopted as a method to counter the rise in methane emissions. Traditionally, landfill soil covers were used to achieve methane oxidation, thereby reducing methane emissions. Meanwhile, the continual rise of CH4 emissions from Landfills and the significant need to and importance of developing a better technology has led researchers to explore different methods to enhance microbial methane oxidation by using organic rich materials such as compost in landfill covers. The development and field application of such bio-based systems, explored by various researches worldwide, eventually led to more widely accepted and better performing cover systems capable of reducing CH4 emissions from Landfills. However, the long-term performance of bio-based cover systems were found to be negatively affected by factors such as the material’s ability to self-degrade, causing CH4 to be generated rather than oxidized as well as the greater potential for forming pore-clogging exopolymeric substances. In order to design an effective cover system for Landfills, it is essential to have a thorough understanding of the concepts incorporated into methodologies currently in favor along with their pros and cons. This review summarizes previous laboratory and field-scale studies conducted on various soil and bio-based cover systems, along with the modeling mechanisms adopted for quantifying CH4 oxidation rates. Finally, several issues and challenges in developing effective and economical soil and bio-based cover systems are presented.
Shaohua Chen - One of the best experts on this subject based on the ideXlab platform.
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Leachate treatment in Landfills is a significant N2O source
Science of The Total Environment, 2017Co-Authors: Xiaojun Wang, Mingsheng Jia, Chengliang Zhang, Shaohua Chen, Zucong CaiAbstract:Abstract The importance of methane (CH4) emissions from Landfills has been extensively documented, while the nitrous oxide (N2O) emissions from Landfills are considered negligible. In this study, three Landfills were selected to measure CH4 and N2O emissions using the static chamber method. Dongbu (DB) and Dongfu (DF) Landfills, both located in Xiamen city, Fujian Province, were classified as sanitary. The former started to receive solid waste from Xiamen city in 2009, and the latter was closed in 2009. Nanjing (NJ) landfill, located in Nanjing county, Fujian Province, was classified as managed. Results showed that for the landfill reservoirs, CH4 emissions were significant, while N2O emissions occurred mainly in operating areas (on average, 16.3 and 19.0 mg N2O m− 2 h− 1 for DB and NJ Landfills, respectively) and made a negligible contribution to the total greenhouse gas emissions in term of CO2 equivalent. However, significant N2O emissions were observed in the leachate treatment systems of sanitary Landfills and contributed 72.8% and 45.6% of total emissions in term of CO2 equivalent in DB and DF Landfills, respectively. The N2O emission factor (EF) of the leachate treatment systems was in the range of 8.9–11.9% of the removed nitrogen. The total N2O emissions from the leachate treatment systems of Landfills in Xiamen city were estimated to be as high as 8.55 g N2O-N capita− 1 yr− 1. These results indicated that N2O emissions from leachate treatment systems of sanitary Landfills were not negligible and should be included in national and/or local inventories of greenhouse gas emissions.
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Leachate treatment in Landfills is a significant N2O source
Science of The Total Environment, 2017Co-Authors: Xiaojun Wang, Mingsheng Jia, Chengliang Zhang, Shaohua Chen, Zucong CaiAbstract:Abstract The importance of methane (CH4) emissions from Landfills has been extensively documented, while the nitrous oxide (N2O) emissions from Landfills are considered negligible. In this study, three Landfills were selected to measure CH4 and N2O emissions using the static chamber method. Dongbu (DB) and Dongfu (DF) Landfills, both located in Xiamen city, Fujian Province, were classified as sanitary. The former started to receive solid waste from Xiamen city in 2009, and the latter was closed in 2009. Nanjing (NJ) landfill, located in Nanjing county, Fujian Province, was classified as managed. Results showed that for the landfill reservoirs, CH4 emissions were significant, while N2O emissions occurred mainly in operating areas (on average, 16.3 and 19.0 mg N2O m− 2 h− 1 for DB and NJ Landfills, respectively) and made a negligible contribution to the total greenhouse gas emissions in term of CO2 equivalent. However, significant N2O emissions were observed in the leachate treatment systems of sanitary Landfills and contributed 72.8% and 45.6% of total emissions in term of CO2 equivalent in DB and DF Landfills, respectively. The N2O emission factor (EF) of the leachate treatment systems was in the range of 8.9–11.9% of the removed nitrogen. The total N2O emissions from the leachate treatment systems of Landfills in Xiamen city were estimated to be as high as 8.55 g N2O-N capita− 1 yr− 1. These results indicated that N2O emissions from leachate treatment systems of sanitary Landfills were not negligible and should be included in national and/or local inventories of greenhouse gas emissions.
