Single-well injection-withdrawal tests as a contaminant transport characterisation tool for landfilled waste
Single-well injection-withdrawal tests as a contaminant transport characterisation tool for landfilled waste
A new single well injection withdrawal (SWIW) test was trialled at four landfills using the tracers lithium and deuterium, and by injecting clean water and measuring electrical conductivity. The aim of the research was to develop a practical test for measuring lateral contaminant transport to aid in the design of landfill flushing. Borehole dilution tests using dyes were undertaken prior to each SWIW test to determine background flow velocities. SWIW tests were performed at different scales by varying the volume of tracer injected (1 to 5,800 m
3) and the test duration (2 to 266 days). Tracers were used individually, simultaneously or sequentially to examine repeatability and scaling. Mobile porosities, estimated from first arrival times in observation wells and from model fitting ranged from 0.02 to 0.14. The low mobile porosities measured rule out a purely advective–dispersive system and support a conceptual model of a highly preferential dual-porosity flow system with localised heterogeneity. A dual-porosity model was used to interpret the results. The model gave a good fit to the test data in 7 out of 11 tests (where R
2 ≥ 0.98), and the parameters derived are compatible with previous experiments in MSW. Block diffusion times were estimated to range from 12 to 6,630 h, with a scaling relationship apparent between the size of the test (volume of tracer used and/or the duration) and the observed block diffusion time. This scaling relationship means affordable small-scale tests can inform larger-scale flushing operations.
Dual-porosity, Flushing, SWIW tests, Tracer Tests, municipal solid waste
142-153
Rees-White, Tristan
852278dd-f628-4d98-a03a-a34fea8c75d6
Woodman, Nicholas
9870f75a-6d12-4815-84b8-6610e657a6ad
Beaven, R.P.
5893d749-f03c-4c55-b9c9-e90f00a32b57
Barker, John
33bf9dec-cc9b-451c-8192-46099e316b6d
Rollinson, James
30e15bb3-3633-45d9-8097-342df979bf0d
1 June 2021
Rees-White, Tristan
852278dd-f628-4d98-a03a-a34fea8c75d6
Woodman, Nicholas
9870f75a-6d12-4815-84b8-6610e657a6ad
Beaven, R.P.
5893d749-f03c-4c55-b9c9-e90f00a32b57
Barker, John
33bf9dec-cc9b-451c-8192-46099e316b6d
Rollinson, James
30e15bb3-3633-45d9-8097-342df979bf0d
Rees-White, Tristan, Woodman, Nicholas, Beaven, R.P., Barker, John and Rollinson, James
(2021)
Single-well injection-withdrawal tests as a contaminant transport characterisation tool for landfilled waste.
Waste Management, 128, .
(doi:10.1016/j.wasman.2021.04.047).
Abstract
A new single well injection withdrawal (SWIW) test was trialled at four landfills using the tracers lithium and deuterium, and by injecting clean water and measuring electrical conductivity. The aim of the research was to develop a practical test for measuring lateral contaminant transport to aid in the design of landfill flushing. Borehole dilution tests using dyes were undertaken prior to each SWIW test to determine background flow velocities. SWIW tests were performed at different scales by varying the volume of tracer injected (1 to 5,800 m
3) and the test duration (2 to 266 days). Tracers were used individually, simultaneously or sequentially to examine repeatability and scaling. Mobile porosities, estimated from first arrival times in observation wells and from model fitting ranged from 0.02 to 0.14. The low mobile porosities measured rule out a purely advective–dispersive system and support a conceptual model of a highly preferential dual-porosity flow system with localised heterogeneity. A dual-porosity model was used to interpret the results. The model gave a good fit to the test data in 7 out of 11 tests (where R
2 ≥ 0.98), and the parameters derived are compatible with previous experiments in MSW. Block diffusion times were estimated to range from 12 to 6,630 h, with a scaling relationship apparent between the size of the test (volume of tracer used and/or the duration) and the observed block diffusion time. This scaling relationship means affordable small-scale tests can inform larger-scale flushing operations.
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Rees-White SWIW Paper
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In preparation date: 16 March 2021
e-pub ahead of print date: 11 May 2021
Published date: 1 June 2021
Additional Information:
Funding Information:
This work was supported by EPSRC Grants EP/E041965/1: Science and strategies for the long-term management and remediation of landfills and EP/I012206/1: Processes, mechanics and management of wastes. George Darling of the British Geological Survey is thanked for performing all deuterium isotope analyses. Relevant data supporting this study are openly available from the University of Southampton repository at: https://doi.org/10.5258/SOTON/D1783.
Funding Information:
This work was supported by EPSRC Grants EP/E041965/1: Science and strategies for the long-term management and remediation of landfills and EP/I012206/1: Processes, mechanics and management of wastes. George Darling of the British Geological Survey is thanked for performing all deuterium isotope analyses.
Publisher Copyright:
© 2021 The Authors
Keywords:
Dual-porosity, Flushing, SWIW tests, Tracer Tests, municipal solid waste
Identifiers
Local EPrints ID: 447913
URI: http://eprints.soton.ac.uk/id/eprint/447913
ISSN: 0956-053X
PURE UUID: 4aee3ed1-7332-49c2-ace5-43b31b65b1bd
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Date deposited: 26 Mar 2021 17:30
Last modified: 17 Mar 2024 03:09
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James Rollinson
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