Long-term operation of a permeable reactive barrier with diffusive exchange

In situ remediation of ammonium-contaminated groundwater is possible through a zeolite permeable reactive barrier (PRB); however, zeolite's finite sorption capacity limits the long-term field application of PRBs. In this paper, a pilot-scale PRB was designed to achieve sustainable use of zeolite in removing ammonium (NH4+-N) through sequential nitrification, adsorption, and denitrification. An oxygen-releasing compound was added to ensure aerobic conditions in the upper layers of the PRB where NH4+-N was microbially oxidized to nitrate. Any remaining NH4+-N was removed abiotically in the zeolite layer. Under lower redox conditions, nitrate formed during nitrification was removed by denitrifying bacteria colonizing the zeolite. During the long-term operation (328 days), more than 90% of NH4+-N was consistently removed, and approximately 40% of the influent NH4+-N was oxidized to nitrate. As much as 60% of the nitrate formed in the PRB was reduced in the zeolite layer after 300 days of operation. Removal of NH4+-N from groundwater using a zeolite PRB through bacterial nitrification and abiotic adsorption is a promising approach. The zeolite PRB has the advantage of achieving sustainable use of zeolite and immediate NH4+-N removal.

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Application of permeable reactive barrier in groundwater remediation

E3S Web of Conferences ◽

10.1051/e3sconf/201913606021 ◽

2019 ◽

Vol 136 ◽

pp. 06021

Author(s):

Qianfeng He ◽

Shihui Si ◽

Jun Yang ◽

Xiaoyu Tu

Keyword(s):

Groundwater Remediation ◽

Low Cost ◽

Structure Type ◽

Permeable Reactive Barrier ◽

Term Operation ◽

Reactive Barrier ◽

External Power ◽

Remediation Design

As a new in-situ remediation of groundwater, compared with the traditional “pump and treat” technology, the permeable reactive barrier (PRB) has the advantages of low cost, no external power, the small disturbance to groundwater, small secondary pollution and long-term operation, this paper introduces the basic concept of PRB, technical principle, structure type, the principle of active materials selection and mechanisms of remediation, design and installation factors, it provides ideas for further research and application of PRB technology in groundwater remediation projects in China.

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Long-Term Performance Evaluation of Permeable Reactive Barrier for Groundwater Remediation Using Visual MODFLOW

Environmental Processes and Management - Water Science and Technology Library ◽

10.1007/978-3-030-38152-3_16 ◽

2020 ◽

pp. 311-320

Author(s):

Rahul Singh ◽

Sumedha Chakma ◽

Volker Birke

Keyword(s):

Performance Evaluation ◽

Groundwater Remediation ◽

Permeable Reactive Barrier ◽

Visual Modflow ◽

Reactive Barrier ◽

Long Term Performance ◽

Term Performance

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Hydrogeochemical and Biological Processes Affecting the Long-term Performance of an Iron-Based Permeable Reactive Barrier

Journal of Environmental Quality ◽

10.2134/jeq2007.0622 ◽

2009 ◽

Vol 38 (3) ◽

pp. 897-908 ◽

Cited By ~ 28

Author(s):

Valerio Zolla ◽

Francesca Stefania Freyria ◽

Rajandrea Sethi ◽

Antonio Di Molfetta

Keyword(s):

Permeable Reactive Barrier ◽

Biological Processes ◽

Reactive Barrier ◽

Iron Based ◽

Long Term Performance ◽

Term Performance

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Evaluation of permeable reactive barrier (PRB) integrity using electrical imaging methods

Geophysics ◽

10.1190/1.1581043 ◽

2003 ◽

Vol 68 (3) ◽

pp. 911-921 ◽

Cited By ~ 33

Author(s):

Lee Slater ◽

Andrew Binley

Keyword(s):

Geophysical Methods ◽

Permeable Reactive Barrier ◽

Electrical Measurements ◽

Cross Sectional ◽

Imaging Methods ◽

Reactive Barrier ◽

Electrical Imaging ◽

Granular Iron

The permeable reactive barrier (PRB) is a promising in‐situ technology for treatment of hydrocarbon‐contaminated groundwater. A PRB is typically composed of granular iron which degrades chlorinated organics into potentially nontoxic dehalogenated organic compounds and inorganic chloride. Geophysical methods may assist assessment of in‐situ barrier integrity and evaluation of long‐term barrier performance. The highly conductive granular iron makes the PRB an excellent target for conductivity imaging methods. In addition, electrochemical storage of charge at the iron–solution interface generates an impedance that decreases with frequency. The PRB is thus a potential induced polarization (IP) target. Surface and cross‐borehole electrical imaging (conductivity and IP) was conducted at a PRB installed at the U.S. Department of Energy's Kansas City plant. Poor signal strength (25% of measurements exceeding 8% reciprocal error) and insensitivity at depth, which results from current channeling in the highly conductive iron, limited surface imaging. Crosshole 2D and 3D electrical measurements were highly effective at defining an accurate, approximately 0.3‐m resolution, cross‐sectional image of the barrier in‐situ. Both the conductivity and IP images reveal the barrier geometry. Crosshole images obtained for seven panels along the barrier suggest variability in iron emplacement along the installation. On five panels the PRB structure is imaged as a conductive feature exceeding 1 S/m. However, on two panels the conductivity in the assumed vicinity of the PRB is less than 1 S/m. The images also suggest variability in the integrity of the contact between the PRB and bedrock. This noninvasive, in‐situ evaluation of barrier geometry using conductivity/IP has broad implications for the long‐term monitoring of PRB performance as a method of hydrocarbon removal.

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