Numerical Study of Landfill Gas Emissions through Three Earthen Landfill Covers
Publication: Journal of Environmental Engineering
Volume 148, Issue 8
Abstract
The effects of different types of earthen landfill covers and vapor on landfill gas emissions are not well understood. In this study, an existing theoretical model of water and multicomponent gas (methane, carbon dioxide, nitrogen, and oxygen) flow was improved by incorporating vapor flow. The model was validated using a published soil column test simulating landfill gas emissions through landfill covers. Numerical simulations were conducted to investigate landfill gas emissions through a single clay-layer cover, a cover with capillary barrier effects (CCBE), and a three-layer cover during continuous drying. The CCBE retained the lowest water content after drying, whereas the bottom clay layer in the three-layer cover stayed almost saturated due to the protection afforded by the top two layers. Accordingly, methane emissions from the CCBE were the highest, whereas those from the three-layer cover were the lowest. Ignoring vapor will predict a drier soil state, and hence will cause methane emissions to be overestimated by 1–2.5 times. Effects of vapor became more significant as the overall gas coefficient of permeability of the cover increased.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
This project was supported by the National Natural Science Foundation of China (Grant Nos. 52178320, 51908134, 42177120, and 51808125).
References
Ahoughalandari, B., and A. R. Cabral. 2017a. “Influence of capillary barrier effect on biogas distribution at the base of passive methane oxidation biosystems: Parametric study.” Waste Manage. 63 (May): 172–187. https://doi.org/10.1016/j.wasman.2016.11.026.
Ahoughalandari, B., and A. R. Cabral. 2017b. “Landfill gas distribution at the base of passive methane oxidation biosystems transient state analysis of several configurations.” Waste Manage. 69 (Nov): 298–314. https://doi.org/10.1016/j.wasman.2017.08.027.
Aitchison, G. D. 1965. “Soil properties, shear strength, and consolidation.” In Proc., 6th Int. Conf. on Soil Mechanics and Foundation Engineering, Montreal, 319–321. Toronto: University of Toronto Press.
Albright, W. H., C. H. Benson, G. W. Gee, T. Abichou, S. W. Tyler, and S. A. Rock. 2006. “Field performance of three compacted clay landfill covers.” Vadose Zone J. 5 (4): 1157–1171. https://doi.org/10.2136/vzj2005.0134.
Aubertin, M., E. Cifuentes, S. A. Apithy, B. Bussiere, J. Molson, and R. P. Chapuis. 2009. “Analyses of water diversion along inclined covers with capillary barrier effects.” Can. Geotech. J. 46 (10): 1146–1164. https://doi.org/10.1139/T09-050.
Babilotte, A., T. Lagier, E. Fiani, and V. Taramini. 2010. “Fugitive methane emissions from landfills: Field comparison of five methods on a French landfill.” J. Environ. Eng. 136 (8): 777–784. https://doi.org/10.1061/(ASCE)EE.1943-7870.0000260.
Benson, C., T. Abichou, W. Albright, G. Gee, and A. Roesler. 2001. “Field evaluation of alternative earthen final covers.” Int. J. Phytorem. 3 (1): 105–127. https://doi.org/10.1080/15226510108500052.
Benson, C. H. 1999. “Final covers for waste containment systems: A north American perspective.” In Proc., 17th Conf., Geotechnics of Torino, Control and Management of Subsoil Pollutants, 1–32. Torino, Italy: Italian Geotechnical Society.
Berger, J. 2008. “Biological methane oxidation in landfill.” Ph.D. thesis, Dept. of Civil Engineering and Geodesy, Darmstadt Technology Univ.
Bian, E. X., D. H. Xin, and X. L. Chai. 2018. “A simulation model for estimating methane oxidation and emission from landfill cover soils.” Waste Manage. 77 (Jul): 426–434. https://doi.org/10.1016/j.wasman.2018.04.029.
Bussière, S., M. Aubertin, and R. P. Chapuis. 2003. “The behavior of inclined covers used as oxygen barriers.” Can. Geotech. J. 40 (3): 512–535. https://doi.org/10.1139/t03-001.
Cao, B.-Y., S.-J. Feng, and A.-Z. Li. 2018. “CFD modelling of anaerobic–aerobic hybrid bioreactor landfills.” Int. J. Geomech. 18 (7): 04018072. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001192.
Carbon Farming Initiative. 2013. Guidelines for calculating regulatory baselines for legacy waste landfill methane projects. Canberra, Australia: Australian Government.
Chen, R., Y. H. Ge, Z. K. Chen, J. Liu, Y. R. Zhao, and Z. H. Li. 2019. “Analytical solution for one-dimensional contaminant diffusion through unsaturated soils beneath geomembrane.” J. Hydrol. 568 (Jan): 260–274. https://doi.org/10.1016/j.jhydrol.2018.10.057.
Chen, R., J. W. Huang, A. K. Leung, Z. K. Chen, and Z. B. Chen. 2022. “Experimental investigation on water release and gas emission of evapotranspirative capillary barrier landfill covers.” Soil Sci. Soc. Am. J. 86 (2): 311–323. https://doi.org/10.1002/saj2.20348.
Chen, Y. M., L. T. Zhan, X. B. Xu, and H. L. Liu. 2013. “Geo-environmental problems in landfills of MSW with high organic content.” In Proc., 18th Int. Conf. on Soil Mechanics and Geotechnical Engineering, 3009–3012. Paris: Presses des Ponts.
Chetri, J. K., K. R. Reddy, and D. G. Grubb. 2021. “Carbon-dioxide and hydrogen-sulfide removal from simulated landfill gas using steel slag.” J. Environ. Eng. 146 (12): 04020139. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001826.
Eun, J., J. M. Tinjum, C. H. Benson, and T. B. Edil. 2018. “Methane transport through simulated landfill covers with a PE geofilm or ethylene-vinyl alcohol, LLDPE, or PVC geomembrane.” J. Environ. Eng. 136 (8): 777–784. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001298.
Ewen, J., and H. R. Thomas. 1989. “Heating unsaturated medium sand.” Géotechnique. 39 (3): 455–470. https://doi.org/10.1680/geot.1989.39.3.455.
Feng, S., H. W. Liu, Q. P. Cai, and W. B. Jian. 2021. “Effects of grass type on hydraulic response of the three-layer landfill cover system.” Waste Manage. Res. 40 (7): 882–891. https://doi.org/10.1177/0734242X211061213.
Feng, S., H. W. Liu, A. C. F. Chiu, and C. W. W. Ng. 2019. “A steady-state analytical profile method for determining methane oxidation in landfill cover.” Sci. Total Environ. 646 (Jan): 1528–1535. https://doi.org/10.1016/j.scitotenv.2018.07.097.
Feng, S., C. W. W. Ng, A. K. Leung, and H. W. Liu. 2017. “Numerical modelling of methane oxidation efficiency and coupled water-gas-heat reactive transfer in a sloping landfill cover.” Waste Manage. 68 (Oct): 355–368. https://doi.org/10.1016/j.wasman.2017.04.042.
Feng, S.-J., Z.-W. Zhu, Z.-L. Chen, and H.-X. Chen. 2020. “Analytical model for multicomponent landfill gas migration through four-layer landfill biocover with capillary barrier.” Int. J. Geomech. 20 (3): 04020001. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001598.
Fredlund, D. G., and H. Rahardjo. 1993. Soil mechanics for unsaturated soils. New York: Wiley.
Garg, A., W. H. Zhou, K. Tai, and M. C. Deo. 2015. “A new simulation approach of genetic programming in modelling of soil water retention property of unsaturated soil.” Eng. Comput. 32 (3): 914–930. https://doi.org/10.1108/EC-05-2014-0110.
Ghavam-Nasiri, A., A. El-Zein, D. Airey, R. K. Rowe, and A. Bouazza. 2019. “Numerical simulation of geosynthetic clay liner desiccation under high thermal gradients and low overburden stress.” Int. J. Geomech. 19 (7): 04019069. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001425.
IPCC (Intergovernmental Panel on Climate Change). 2013. “Climate change 2013: The physical science basis.” In Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge, UK: Cambridge University Press.
Irvine, T. F., and P. E. Liley. 1984. Steam and gas tables with computer equations. Orlando, FL: Academic Press.
Li, G. Y., L. T. Zhan, and W. J. Xu. 2018. “Influence of thermal gradient and vapor content of landfill gas on water storage in the loess-gravel cover.” In Proc., 7th Int. Conf. on Unsaturated Soils, 1318–1324. Hong Kong: Hong Kong Univ. of Science and Technology.
Ministry of Chemical Industry of the PRC. 1979. Cryogenic handbook. Beijing: Chemical Industry Press.
Ministry of Construction of the PRC. 2007. Technical code for municipal solid waste sanitary landfill closure. CJJ 112. Beijing: Ministry of Construction of the PRC.
Moldrup, P., T. Olesen, J. Gamst, P. Schjønning, T. Yamaguchi, and D. E. Rolston. 2000. “Predicting the gas diffusion coefficient in repacked soil: Water-induced linear reduction model.” Soil Sci. Soc. Am. J. 64 (5): 1588–1594. https://doi.org/10.2136/sssaj2000.6451588x.
Mualem, Y. 1976. “A new model for predicting the hydraulic conductivity of unsaturated porous media.” Water Resour. Res. 12 (3): 513–522. https://doi.org/10.1029/WR012i003p00513.
Nastev, M. 1998. “Modeling landfill gas generation and migration in sanitary landfills and geological formations.” Ph.D. thesis, Dept. of Geological Engineering, Univ. of Calgary.
Ng, C. W. W., R. Chen, J. L. Coo, J. Liu, J. J. Y. M. NiChen, Y. M. Chen, L. T. Zhan, H. W. Guo, and B. W. Lu. 2019. “A novel vegetated three-layer landfill cover system using recycled construction wastes without geomembrane.” Can. Geotech. J. 56 (7): 1863–1875. https://doi.org/10.1139/cgj-2017-0728.
Ng, C. W. W., J. L. Coo, Z. K. Chen, and R. Chen. 2016. “Water infiltration into a new three-layer landfill cover system.” J. Environ. Eng. 142 (5): 04016007. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001074.
Ng, C. W. W., S. Feng, and H. W. Liu. 2015a. “A fully coupled model for water–gas–heat reactive transport with methane oxidation in landfill covers.” Sci. Total Environ. 508 (Mar): 307–319. https://doi.org/10.1016/j.scitotenv.2014.11.037.
Ng, C. W. W., J. Liu, and R. Chen. 2015b. “Numerical investigation on gas emission from three landfill soil covers under dry weather conditions.” Vadose Zone J. 14 (Aug): 8. https://doi.org/10.2136/vzj2014.12.0180.
Ng, C. W. W., J. Liu, R. Chen, and J. Xu. 2015c. “Physical and numerical modelling of an inclined three-layer (silt/gravelly sand/clay) capillary barrier cover system under extreme rainfall.” Waste Manage. 38 (Apr): 210–221. https://doi.org/10.1016/j.wasman.2014.12.013.
Parker, J. C. 1989. “Multiphase flow and transport in porous media.” Rev. Geophys. 27 (3): 311–328. https://doi.org/10.1029/RG027i003p00311.
Phillip, J. R., and D. A. De Vries. 1957. “Moisture movement in porous materials under temperature gradients.” Trans. Am. Geophys. Union 38 (Feb): 222–232. https://doi.org/10.1029/TR038i002p00222.
Rahardjo, H., V. A. Santoso, E. C. Leong, Y. S. Ng, C. P. H. Tam, and A. Satyanaga. 2013. “Use of recycled crushed concrete and Secudrain in capillary barriers for slope stabilization.” Can. Geotech. J. 50 (6): 662–673. https://doi.org/10.1139/cgj-2012-0035.
Reddy, K. R., E. N. Yargicoglu, and J. K. Chetri. 2021. “Effects of biochar on methane oxidation and properties of landfill cover soil: Long-term column incubation tests.” J. Environ. Eng. 147 (1): 04020144. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001829.
Reid, R. C., J. M. Prausnitz, and B. E. Poling. 1987. The properties of gases and liquids. New York: McGraw-Hill.
Ross, B. 1990. “The diversion capacity of capillary barriers.” Water Resour. Res. 26 (Sep): 2625–2629. https://doi.org/10.1029/WR026i010p02625.
SAIC (Science Applications International Corporation). 1999. Quality assurance project plan for the alternative cover assessment project. Hackensack, NJ: SAIC.
Scarfone, R., S. J. Wheeler, and M. Lloret-Cabot. 2020. “Conceptual hydraulic conductivity model for unsaturated soils at low degree of saturation and its application to the study of capillary barrier systems.” J. Geotech. Geoenviron. Eng. 146 (10): 04020106. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002357.
Scheutz, C., P. Kjeldsen, J. E. Bogner, A. De Visscher, J. Gebert, H. A. Hilger, M. Huber-Humer, and K. Spokas. 2009. “Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions.” Waste Manage. Res. 27 (5): 409–455. https://doi.org/10.1177/0734242X09339325.
Shen, S. L., Y. M. Chen, L. T. Zhan, H. J. Xie, A. Bouazza, F. Y. He, and X. R. Zuo. 2018. “Methane hotspot localization and visualization at a large-scale Xi’an landfill in China: Effective tool for landfill gas management.” J. Environ. Manage. 225 (2): 232–241. https://doi.org/10.1016/j.jenvman.2018.08.012.
Stoltz, G., A. J. Tinet, M. J. Staub, L. Oxarango, and J.-P. Gourc. 2012. “Moisture retention properties of municipal solid waste in relation to compression.” J. Geotech. Geoenviron. Eng. 138 (4): 535–543. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000616.
van Genuchten, T. M. 1980. “A closed-form equation for predicting the hydraulic conductivity of unsaturated soils.” Soil Sci. Soc. Am. J. 44 (5): 892–898. https://doi.org/10.2136/sssaj1980.03615995004400050002x.
Wang, Q., X. R. Zuo, M. Xia, H. J. Xie, F. Y. He, S. L. Shen, A. Bouazza, and L. L. Zhu. 2019. “Field investigation of temporal variation of volatile organic compounds at a landfill in Hangzhou, China.” Environ. Sci. Pollut. Res. 26 (18): 18162–18180. https://doi.org/10.1007/s11356-019-04917-5.
Xie, H. J., Q. Wang, A. Bouazza, and S. J. Feng. 2018. “Analytical model for vapour-phase VOCs transport in four-layered landfill composite cover systems.” Comput. Geotech. 101 (Sep): 80–94. https://doi.org/10.1016/j.compgeo.2018.04.021.
Yang, T., W. Sun, and D. Yue. 2017. “Characterizing the effects of biologically active covers on landfill methane emission flux and bio-oxidation.” J. Environ. Eng. 143 (9): 04017059. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001251.
Zhan, L. T., Q. W. Qiu, W. J. Xu, and Y. M. Chen. 2016. “Field measurement of gas permeability of compacted loess used as an earthen final cover for a municipal solid waste landfill.” J. Zhejiang Univ.- Sci. A (Appl. Phys. Eng.) 17 (7): 541–552. https://doi.org/10.1631/jzus.A1600245.
Zhan, L.-T., G.-Y. Li, W.-G. Jiao, J.-W. Lan, Y.-M. Chen, and W. Shi. 2020a. “Performance of a compacted loess/gravel cover as a capillary barrier and landfill gas emissions controller in Northwest China.” Sci. Total Environ. 718 (2): 137195. https://doi.org/10.1016/j.scitotenv.2020.137195.
Zhan, L.-T., T. Wu, S. Feng, G.-Y. Li, H.-J. He, J.-W. Lan, and Y.-M. Chen. 2020b. “Full-scale experimental study of methane emission in a loess-gravel capillary barrier cover under different seasons.” Waste Manage. 107 (Apr): 54–65. https://doi.org/10.1016/j.wasman.2020.03.026.
Zhang, L. M., and Y. Q. Ke. 2017. “Combinations of soil materials for granular capillary barriers for minimizing rainfall infiltration and gas emission.” Can. Geotech. J. 54 (11): 1580–1591. https://doi.org/10.1139/cgj-2016-0334.
Zhou, Y., and R. K. Rowe. 2005. “Modeling of clay liner desiccation.” Int. J. Geomech. 5 (1): 1–9. https://doi.org/10.1061/(ASCE)1532-3641(2005)5:1(1).
Zienkiewicz, O. C., R. L. Taylor, and P. Nithiarasu. 2005. The finite element method for fluid dynamics. Amsterdam, Netherlands: Elsevier.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 148 • Issue 8 • August 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Dec 3, 2021
Accepted: Mar 18, 2022
Published online: Jun 7, 2022
Published in print: Aug 1, 2022
Discussion open until: Nov 7, 2022
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
Cited by
- S. Feng, S. F. Huang, J. L. Jiang, L. T. Zhan, G. Y. Li, R. Q. Guan, H. W. Guo, H. W. Liu, Effects of Pore-Size Distribution on the Gas Diffusion Coefficient and Gas Permeability of Compacted Manufactured Sand Tailing–Bentonite Mixtures, Journal of Geotechnical and Geoenvironmental Engineering, 10.1061/JGGEFK.GTENG-11303, 149, 11, (2023).
- Tao Wu, Liangtong Zhan, Song Feng, Ping Chen, Numerical analysis of moisture and gas transport in earthen final covers considering effects of vapor and temperature gradient, Soils and Foundations, 10.1016/j.sandf.2022.101262, 63, 1, (101262), (2023).
- Ming Min, He-Fu Pu, Song Feng, Jin-Wei Qiu, Xiao-Jun Wen, Analytical solution for coupled water–gas transport in unsaturated landfill cover system with different root architectures, Computers and Geotechnics, 10.1016/j.compgeo.2022.105134, 154, (105134), (2023).