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Integrating NZVI and carbon substrates in a non-pumping reactive wells array for the remediation of a nitrate contaminated aquifer.
J Contam Hydrol. 2015 Aug; 179:182-95.JC

Abstract

The work explores the efficacy of a biochemical remediation of a nitrate-contaminated aquifer by a combination of nanoscale zero-valent iron (NZVI) and bacteria supported by carbon substrates. Nitrate removal was first assessed in batch tests, and then in a laboratory bench-scale aquifer model (60cm length×40cm width×50cm height), in which a background flow was maintained. Water and natural sandy material of a stratified aquifer were used in the tests to enhance the reliability of the results. An array of non-pumping-reactive wells (NPRWs) filled with NZVI (d50=50nm, and SSA=22.5m(2)/g) mixed with carbon substrates (beech sawdust and maize cobs) was installed in the bench-scale aquifer model to intercept the flow and remove nitrate (NO3(-) conc.=105mg/l). The NPRW array was preferred to a continuous permeable reactive barrier (PRB) since wells can be drilled at greater depths compared to PRBs. The optimal well diameter, spacing among the NPRWs and number of wells in the bench-scale model were designed based on flow simulations using the semi-analytical particle tracking (advection) model, PMPATH. An optimal configuration of four wells, 35mm diameter, and capture width of 1.8 times the well diameter was obtained for a hydraulic conductivity contrast between reactive materials in the wells and aquifer media (KPM/Kaq=16.5). To avoid excessive proximity between wells, the system was designed so that the capture of the contaminated water was not complete, and several sequential arrays of wells were preferred. To simulate the performance of the array, the water that passed through the bench-scale NPRW system was re-circulated to the aquifer inlet, and a nitrate degradation below the limit target concentration (10mg/l) was obtained after 13days (corresponding to 13 arrays of wells in the field). The results of this study demonstrated that using the NZVI-mixed-carbon substrates in the NPRW system has a great potential for in-situ nitrate reduction in contaminated groundwater. This NPRW system can be considered a promising and viable technology in deep aquifers.

Authors+Show Affiliations

Natural Geography Department, University of Tehran, Tehran, P.O. Box: 14155-6465, Iran. Electronic address: smhosseini@ut.ac.ir.Dipartimento di Ingegneria dell'Ambiente, del Territorio e delle Infrastrutture, Politecnico di Torino, Torino, Italy.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26142547

Citation

Hosseini, Seiyed Mossa, and Tiziana Tosco. "Integrating NZVI and Carbon Substrates in a Non-pumping Reactive Wells Array for the Remediation of a Nitrate Contaminated Aquifer." Journal of Contaminant Hydrology, vol. 179, 2015, pp. 182-95.
Hosseini SM, Tosco T. Integrating NZVI and carbon substrates in a non-pumping reactive wells array for the remediation of a nitrate contaminated aquifer. J Contam Hydrol. 2015;179:182-95.
Hosseini, S. M., & Tosco, T. (2015). Integrating NZVI and carbon substrates in a non-pumping reactive wells array for the remediation of a nitrate contaminated aquifer. Journal of Contaminant Hydrology, 179, 182-95. https://doi.org/10.1016/j.jconhyd.2015.06.006
Hosseini SM, Tosco T. Integrating NZVI and Carbon Substrates in a Non-pumping Reactive Wells Array for the Remediation of a Nitrate Contaminated Aquifer. J Contam Hydrol. 2015;179:182-95. PubMed PMID: 26142547.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Integrating NZVI and carbon substrates in a non-pumping reactive wells array for the remediation of a nitrate contaminated aquifer. AU - Hosseini,Seiyed Mossa, AU - Tosco,Tiziana, Y1 - 2015/07/02/ PY - 2014/10/25/received PY - 2015/05/19/revised PY - 2015/06/22/accepted PY - 2015/7/6/entrez PY - 2015/7/6/pubmed PY - 2016/6/28/medline KW - Aquifer remediation KW - Carbon substrates KW - Nano zero valent iron KW - Nitrate removal KW - Non-pumping reactive wells KW - PMPATH SP - 182 EP - 95 JF - Journal of contaminant hydrology JO - J. Contam. Hydrol. VL - 179 N2 - The work explores the efficacy of a biochemical remediation of a nitrate-contaminated aquifer by a combination of nanoscale zero-valent iron (NZVI) and bacteria supported by carbon substrates. Nitrate removal was first assessed in batch tests, and then in a laboratory bench-scale aquifer model (60cm length×40cm width×50cm height), in which a background flow was maintained. Water and natural sandy material of a stratified aquifer were used in the tests to enhance the reliability of the results. An array of non-pumping-reactive wells (NPRWs) filled with NZVI (d50=50nm, and SSA=22.5m(2)/g) mixed with carbon substrates (beech sawdust and maize cobs) was installed in the bench-scale aquifer model to intercept the flow and remove nitrate (NO3(-) conc.=105mg/l). The NPRW array was preferred to a continuous permeable reactive barrier (PRB) since wells can be drilled at greater depths compared to PRBs. The optimal well diameter, spacing among the NPRWs and number of wells in the bench-scale model were designed based on flow simulations using the semi-analytical particle tracking (advection) model, PMPATH. An optimal configuration of four wells, 35mm diameter, and capture width of 1.8 times the well diameter was obtained for a hydraulic conductivity contrast between reactive materials in the wells and aquifer media (KPM/Kaq=16.5). To avoid excessive proximity between wells, the system was designed so that the capture of the contaminated water was not complete, and several sequential arrays of wells were preferred. To simulate the performance of the array, the water that passed through the bench-scale NPRW system was re-circulated to the aquifer inlet, and a nitrate degradation below the limit target concentration (10mg/l) was obtained after 13days (corresponding to 13 arrays of wells in the field). The results of this study demonstrated that using the NZVI-mixed-carbon substrates in the NPRW system has a great potential for in-situ nitrate reduction in contaminated groundwater. This NPRW system can be considered a promising and viable technology in deep aquifers. SN - 1873-6009 UR - https://www.unboundmedicine.com/medline/citation/26142547/Integrating_NZVI_and_carbon_substrates_in_a_non_pumping_reactive_wells_array_for_the_remediation_of_a_nitrate_contaminated_aquifer_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0169-7722(15)30002-4 DB - PRIME DP - Unbound Medicine ER -