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Kissas K, Kjeldsen P, Ibrom A, Scheutz C. The effect of barometric pressure changes on the performance of a passive biocover system, Skellingsted landfill, Denmark. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 156:216-226. [PMID: 36493665 DOI: 10.1016/j.wasman.2022.11.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 11/01/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
This study investigated the performance of a passive biocover system at a Danish landfill. The overall methane oxidation efficiency of the system was assessed by comparing annual whole-site methane emissions before and after biocover installation. Annual whole-site methane emission predictions were calculated based on empirical models developed by a discrete number of tracer gas dispersion measurements. Moreover, a series of field campaigns and continuous flux measurements was carried out to evaluate the functionality of an individual biowindow. The results indicated that biocover system performance highly depended on barometric pressure variations. Under decreasing barometric pressure, estimated efficiency declined to 20%, while under increasing barometric pressure, nearly 100% oxidation was achieved. In-situ measurements on a specific biowindow showed a similar oxidation efficiency pattern in respect to barometric pressure changes despite the difference in spatial representation. Eddy covariance results revealed pronounced seasonal variability in the investigated biowindow, measuring higher methane fluxes during the cold period compared to the warm period. Results from the in-situ campaigns confirmed this finding, reporting a threefold increase in the biowindow's methane oxidation capacity from April to May. The annual average oxidation efficiency of the system was estimated to range between 51% and 65%, taking into consideration the impact of changes in barometric pressure and seasonal variability. This indicated an annual reduction in landfill's methane emissions between 24 and 35 tonnes. This study revealed the challenge facing current approaches in documenting accurately the performance of a passive biocover system, due to the short-term variability of oxidation efficiency, which is influenced by barometric pressure changes.
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Affiliation(s)
- K Kissas
- Department of Environmental and Resource Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - P Kjeldsen
- Department of Environmental and Resource Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - A Ibrom
- Department of Environmental and Resource Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - C Scheutz
- Department of Environmental and Resource Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
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2
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Nelson B, Zytner RG, Dulac Y, Cabral AR. Mitigating fugitive methane emissions from closed landfills: A pilot-scale field study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158351. [PMID: 36049680 DOI: 10.1016/j.scitotenv.2022.158351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 08/12/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Emissions from Canadian landfills account for 20 % of national greenhouse gas emissions, a portion of which occur as fugitive emissions. Depending on management factors, significant quantities of landfill gas are emitted during the operational phase and over several decades following landfill closure. Successful landfill reclamation developments depend on low-maintenance solutions to manage fugitive emissions. Designing passive methane oxidation biosystems (PMOBs) to complement landfill covers has become a promising complementary strategy. Achieving year-round methane oxidation in cold climates, requires specific conditions for survival of methanotrophic bacteria (responsible for methane oxidation), including optimal temperature, moisture and sufficient supply of O2 and CH4. The objective of this study was to design, construct and monitor a fully instrumented pilot-scale PMOB capable of abating fugitive methane emissions from a closed landfill in the city of Kitchener, Ontario, now a public park. Factors considered in the design include type of PMOB media, methane loading rates, hydraulic behaviour and ambient temperature. Methane oxidation efficiencies between 73 and 100 % were achieved during the monitoring period. The goal was to develop a long-term solution to mitigate fugitive methane emissions at this closed landfill. Successful mitigation will provide a low-maintenance, high impact technology that could be adopted by the municipality for abatement of CH4 emissions at other landfills under its management. The results will also be useful to landfill designers, operators, and regulatory bodies. Overall, the PMOB construction and monitoring results supported evidence that the designed PMOB was capable of abating most of the CH4 loading. The paper describes several steps taken to design, install and operate the PMOB.
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Affiliation(s)
- Brienne Nelson
- Dillon Consulting Ltd. (formerly with Univ. of Guelph), Canada
| | - Richard G Zytner
- School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Yohan Dulac
- Dept. of Civil and Building Eng., Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Alexandre R Cabral
- Dept. of Civil and Building Eng., Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
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Duan Z, Scheutz C, Kjeldsen P. Mitigation of methane emissions from three Danish landfills using different biocover systems. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 149:156-167. [PMID: 35738145 DOI: 10.1016/j.wasman.2022.05.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 05/02/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
The establishment of biocover systems is an emerging methodology in reducing methane (CH4) emissions from landfills. This study investigated the performance of three biocover systems with different designs (biowindow and passively and actively loaded biofilters) in mitigating CH4 emissions from three landfills in Denmark. A series of field tests were carried out to evaluate the functionality of each system, and total CH4 emissions from relevant landfill sections or the entire landfill were measured before and after biocover implementation. Surface CH4 concentration screening and local CH4 fluxes showed generally low emissions from the biowindow/biofilters (mostly < 5 g CH4 m-2 d-1), although some hotspots were identified on two actively loaded biofilters. One passively loaded biofilter exhibited high CH4 emissions, mainly due to gas overloading into the system. Gas concentration profiles measured at different locations suggested uneven gas distribution in the biofilters, and significant CH4 oxidation occurred in both the gas distribution layer (when oxygen was fed into the system) and the CH4 oxidation layer. High CH4 oxidation efficiencies of above 95% were found in all systems except for one biofilter (55%). Whole-site emission measurements showed CH4 reduction efficiencies between 29 and 72% after implementing biocover systems at the three landfills, suggesting that they were efficient in reducing CH4 emissions. The most challenging task for the passively loaded biocover systems was to control gas flow and secure homogenous gas distribution, while for actively loaded biocovers, it might be more important to eliminate emission hotspots for better functionality.
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Affiliation(s)
- Zhenhan Duan
- Department of Environmental Engineering, Building 115, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Charlotte Scheutz
- Department of Environmental Engineering, Building 115, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Peter Kjeldsen
- Department of Environmental Engineering, Building 115, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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Jawad J, Khalil MJ, Sengar AK, Zaidi SJ. Experimental analysis and modeling of the methane degradation in a three stage biofilter using composted sawdust as packing media. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 286:112214. [PMID: 33639422 DOI: 10.1016/j.jenvman.2021.112214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
Methane gas is a very effective greenhouse gas and the second-largest contributor to global warming. Biofiltration is an effective technology that uses microorganisms to degrade the pollutant by oxidizing it. In this work, the performance of a biofilter with supporting filter media, consisting of composted sawdust, is evaluated at three different sampling ports. Furthermore, a transient model is developed to predict methane concentration at various heights and times. The developed model is validated with the experimental data and shows good agreement with the experimental data. The highest removal efficiency and elimination capacity was found to be 72% and 0.108 g m-3 h-1 respectively. The effect of parameters such as specific surface area, the reaction rate constant, biofilm thickness and airflow rate were studied on the outlet methane concentration. Under similar conditions, the simulations showed that the removal efficiency of 95% might be achieved for the height of 2 m.
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Affiliation(s)
- Jasir Jawad
- Centre for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Mohd Junaid Khalil
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh, 202002, India.
| | - Anoop Kumar Sengar
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh, 202002, India
| | - Syed Javaid Zaidi
- Centre for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar.
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Duan Z, Hansen POR, Scheutz C, Kjeldsen P. Mitigation of methane and trace gas emissions through a large-scale active biofilter system at Glatved landfill, Denmark. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 126:367-376. [PMID: 33813314 DOI: 10.1016/j.wasman.2021.03.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/08/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Biocover systems are a cost-effective technology utilised to mitigate methane (CH4) and trace gas emissions from landfills. A full-scale biofilter system was constructed at Glatved landfill, Denmark, consisting of three biofilters with a total area of 3950 m2. Landfill gas collected mainly from shredder waste cells was mixed with ambient air and fed actively into the biofilter, resulting in an average load of 60-75 g m-2 d-1 for CH4 and 0.15-0.21 g m-2 d-1 for trace gases (e.g., aromatics, chlorofluorocarbons (CFCs), aliphatic hydrocarbons). The initial CH4 surface screening showed uneven gas distribution into the system, and elevated surface concentrations were observed close to the gas inlet. Both positive and negative CH4 fluxes, ranging from -0.36 to 4.25 g m-2 d-1, were measured across the surface of the biofilter. Total trace gas emissions were between -0.005 and 0.042 g m-2 d-1, and the emission flux of individual compounds were generally small (10-8 to 10-3 g m-2 d-1). Vertical gas concentration profiles showed that the oxidation of CH4 and easily degradable trace compounds such as aromatics and aliphatic hydrocarbons happened in the aerobic zones, while CFCs were degraded in the anaerobic zone inside the compost layer. In addition, oxidation/degradation of CH4 and trace gases also occurred in the gas distribution layer, which contributed significantly to the overall mitigation efficiency of the biofilter system. Overall, the biofilter system showed mitigation efficiencies of nearly 100% for both CH4 and trace gases, and it might have the potential to work under higher loads.
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Affiliation(s)
- Zhenhan Duan
- Department of Environmental Engineering, Building 115, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
| | | | - Charlotte Scheutz
- Department of Environmental Engineering, Building 115, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Peter Kjeldsen
- Department of Environmental Engineering, Building 115, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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Methane Oxidation Efficiency in Biofiltration Systems with Different Moisture Content Treating Diluted Landfill Gas. ENERGIES 2020. [DOI: 10.3390/en13112872] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study investigates the influence of moisture content on the potential oxidation efficiency of methane (CH4) of biofiltration systems treating landfill gas containing high oxygen concentrations. Column tests filled with compost with different moisture contents (20%, 30%, and 40%) loaded with different methane flows were set up on a laboratory scale. Analyzing the results the following evidences can be summarized: With low methane load (<100 g CH4 m−2 d−1), a moisture content of 20% was not enough to support bacterial activity, while a moisture content of 40% advantaged the compost respiration assisting it to become the dominating process; with higher methane load (100–300 g CH4 m−2 d−1), a moisture content of 30% resulted in an optimal value to support methanotrophic activity showing the highest CH4 concentration reduction; moving on to a CH4 load above 300 g CH4 m−2 d−1, the inhibition of methanotrophic activity emerged independently to the moisture content of the filter media. The optimal configuration is obtained for a moisture content of 30% and in the case of flows below 200 g CH4 m−2 d−1 for which the oxidation efficiency results higher than 80%.
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Ahmadi N, Mosthaf K, Scheutz C, Kjeldsen P, Rolle M. Model-based interpretation of methane oxidation and respiration processes in landfill biocovers: 3-D simulation of laboratory and pilot experiments. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 108:160-171. [PMID: 32353781 DOI: 10.1016/j.wasman.2020.04.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/06/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Landfill biocovers are an efficient strategy for the mitigation of greenhouse gas emissions from landfills. A complex interplay between key physical and reactive processes occurs in biocovers and affects the transport of gas components. Therefore, numerical models can greatly help the understanding of these systems, their design and optimal operation. In this study, we developed a 3-D multicomponent modeling approach to quantitatively interpret experimental datasets measured in the laboratory and in pilot-scale landfill biocovers. The proposed model is able to reproduce the observed spatial and temporal dynamics of CH4, O2 and CO2 migration in biocovers under different operating conditions and demonstrates the importance of dimensionality in understanding the propagation of gas flow and migration of gas components in such porous media. The model allowed us to capture the coupled transport behavior of gas components, to evaluate the exchange of gas fluxes at the interface between the biocover surface and free air flow, and to investigate the effects of different gas injection patterns on the distribution of gas components within biocovers. The model also helps elucidating the dynamics and competition between methane oxidation and respiration processes observed in the different experimental setups. The simulation outcomes reveal that increasing availability of methane (i.e., higher injection flow rates or higher fractions of CH4 in the injected gas composition) results in progressive dominance of methane oxidation in the biocovers and moderates the impact of respiration.
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Affiliation(s)
- Navid Ahmadi
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs. Lyngby, Denmark
| | - Klaus Mosthaf
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs. Lyngby, Denmark
| | - Charlotte Scheutz
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs. Lyngby, Denmark
| | - Peter Kjeldsen
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs. Lyngby, Denmark
| | - Massimo Rolle
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs. Lyngby, Denmark.
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Mitigation of Methane, NMVOCs and Odor Emissions in Active and Passive Biofiltration Systems at Municipal Solid Waste Landfills. SUSTAINABILITY 2020. [DOI: 10.3390/su12083203] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Biofiltration systems are emerging technological solutions for the removal of methane and odors from landfill gas when flaring is no longer feasible. This work analyzed and compared two full-scale biofiltration systems: biofilter and biowindows. The emission mitigation of methane, non-methane volatile organic compounds (NMVOCs) and odors during a two-year management and monitoring period was studied. In addition to diluted methane, more than 50 NMVOCs have been detected in the inlet raw landfill gas and the sulfur compounds resulted in the highest odor activity value. Both systems, biofilter and biowindows, were effective for the oxidation of methane (58.1% and 88.05%, respectively), for the mitigation of NMVOCs (higher than 80%) and odor reduction (99.84% and 93.82% respectively). As for the biofilter monitoring, it was possible to define the oxidation efficiency trend and in fact to guarantee that for an oxidation efficiency of 80%, the methane load must be less than 6.5 g CH4/m2h with an oxidation rate of 5.2 g CH4/m2h.
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