New Simplified Models of Single‐Well Push‐Pull Tests With Mixing Effect

Single-well, push-pull tests were conducted in a contaminated aquifer to evaluate the ability of toluene-oxidizing microorganisms to cometabolize chlorinated aliphatic hydrocarbons (CAHs), such as trichloroethene (TCE). Test solutions were injected into the aquifer using a standard monitoring well, and then were transported under natural-gradient conditions. Transport tests demonstrated similar transport characteristics of the conservative tracer and the reactive solutes. Biostimulation tests were then performed by injecting a test solution containing dissolved toluene substrate, hydrogen peroxide, bromide, and nitrate in order to increase the biomass of toluene-utilizing microorganisms. Decreases in toluene concentration and the production of o-cresol as an intermediate oxidation product indicated the simulation of toluene-utilizing microorganisms containing an ortho-monooxygenase enzyme. Transformation tests demonstrated that indigenous microorganisms had the capability to transform the surrogate compounds (e.g. isobutene) and both cis-dichloroethene (cis-DCE) and trans-dichloroethene (trans-DCE). Isobutene was transformed to isobutene oxide, indicating transformation by a toluene ortho-monooxygenase, and both cis-DCE and trans-DCE were transformed. In a final test, the utilization of toluene, and the transformation of isobutene, cis-DCE, and trans-DCE were all inhibited in the presence of 1-butyne, a known inhibitor of the toluene ortho-monooxygenase enzyme. The method assessed the activity of attached microorganisms under in situ conditions of bioremediation.

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Estimating In Situ Biodegradation Rates of Petroleum Hydrocarbons and Microbial Population Dynamics by Performing Single-Well Push–Pull Tests in a Fractured Bedrock Aquifer

Water Air & Soil Pollution ◽

10.1007/s11270-012-1364-5 ◽

2013 ◽

Vol 224 (2) ◽

Cited By ~ 7

Author(s):

Yunchul Cho ◽

Kyungjin Han ◽

Namhee Kim ◽

Sunhwa Park ◽

Young Kim

Keyword(s):

Petroleum Hydrocarbons ◽

Microbial Population ◽

Fractured Bedrock ◽

Fractured Bedrock Aquifer ◽

Single Well ◽

Microbial Population Dynamics ◽

Pull Tests ◽

Bedrock Aquifer ◽

In Situ Biodegradation

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Push-pull tests for estimating effective porosity: expanded analytical solution and in situ application

Hydrogeology Journal ◽

10.1007/s10040-017-1672-3 ◽

2017 ◽

Vol 26 (2) ◽

pp. 381-393 ◽

Cited By ~ 13

Author(s):

Charles J. Paradis ◽

Larry D. McKay ◽

Edmund Perfect ◽

Jonathan D. Istok ◽

Terry C. Hazen

Keyword(s):

Analytical Solution ◽

Center Of Mass ◽

Unconfined Aquifer ◽

Effective Porosity ◽

Pull Test ◽

True Value ◽

Single Well ◽

Pull Tests ◽

Injection Phase

Abstract The analytical solution describing the one-dimensional displacement of the center of mass of a tracer during an injection, drift, and extraction test (push-pull test) was expanded to account for displacement during the injection phase. The solution was expanded to improve the in situ estimation of effective porosity. The truncated equation assumed displacement during the injection phase was negligible, which may theoretically lead to an underestimation of the true value of effective porosity. To experimentally compare the expanded and truncated equations, single-well push-pull tests were conducted across six test wells located in a shallow, unconfined aquifer comprised of unconsolidated and heterogeneous silty and clayey fill materials. The push-pull tests were conducted by injection of bromide tracer, followed by a non-pumping period, and subsequent extraction of groundwater. The values of effective porosity from the expanded equation (0.6–5.0%) were substantially greater than from the truncated equation (0.1–1.3%). The expanded and truncated equations were compared to data from previous push-pull studies in the literature and demonstrated that displacement during the injection phase may or may not be negligible, depending on the aquifer properties and the push-pull test parameters. The results presented here also demonstrated the spatial variability of effective porosity within a relatively small study site can be substantial, and the error-propagated uncertainty of effective porosity can be mitigated to a reasonable level (< ± 0.5%). The tests presented here are also the first that the authors are aware of that estimate, in situ, the effective porosity of fine-grained fill material.

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In situ evaluation of solute retardation using single-well push–pull tests

Advances in Water Resources ◽

10.1016/s0309-1708(00)00023-3 ◽

2000 ◽

Vol 24 (1) ◽

pp. 105-117 ◽

Cited By ~ 54

Author(s):

M.H Schroth ◽

J.D Istok ◽

R Haggerty

Keyword(s):

Single Well ◽

Pull Tests

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Assessing the activity and diversity of fumarate-fed denitrifying bacteria by performing field single-well push-pull tests

Journal of Environmental Science and Health Part A ◽

10.1080/10934529.2011.526080 ◽

2011 ◽

Vol 46 (1) ◽

pp. 33-41 ◽

Cited By ~ 4

Author(s):

Jin-Hoon Kim ◽

Chul-Yoon Ha ◽

Seong-Wook Oa ◽

Jin-Woo Lee ◽

Sun-Hwa Park ◽

...

Keyword(s):

Denitrifying Bacteria ◽

Single Well ◽

Pull Tests

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Monitoring Bioaugmenation with Single-Well Push−Pull Tests in Sediment Systems Contaminated with Trichloroethene

Environmental Science & Technology ◽

10.1021/es9019645 ◽

2010 ◽

Vol 44 (3) ◽

pp. 1085-1092 ◽

Cited By ~ 4

Author(s):

Jae-Hyuk Lee ◽

Mark Dolan ◽

Jennifer Field ◽

Jonathan Istok

Keyword(s):

Single Well ◽

Pull Tests

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A single well push–pull test method for in situ determination of denitrification rates in a nitrate-contaminated groundwater aquifer

Water Science & Technology ◽

10.2166/wst.2005.0230 ◽

2005 ◽

Vol 52 (8) ◽

pp. 77-86 ◽

Cited By ~ 10

Author(s):

Y. Kim ◽

J.H. Kim ◽

B.H. Son ◽

S.W. Oa

Keyword(s):

Nitrous Oxide ◽

Ground Water ◽

Test Solution ◽

Test Method ◽

Water Mixture ◽

Pull Test ◽

Single Well ◽

Pull Tests

In this study a single-well, “push–pull” test method is adapted for determination of in situ denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push–pull tests. The method consists of the controlled injection of a prepared test solution (“push”) into an aquifer followed by the extraction of the test solution/ground water mixture (“pull”) from the same location. The injected test solution consists of ground water containing a nonreactive tracer and one or more biologically reactive solutes. Reaction rate coefficients are computed from the mass of reactant consumed and/or product formed. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). Extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifying microorganisms and consisted of injection of site ground water containing fumarate and nitrate. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate > nitrite > nitrous oxide. The series of push–pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ denitrification in nitrate-contaminated aquifers.

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