Preferential flow path development and its influence on long-term PRB performance: column study

Kamolpornwijit, Wiwat; Liang, Liyuan; West, O.R.; Moline, Gerilynn R.; Sullivan, Annett B.

doi:10.1016/s0169-7722(03)00031-7

Cited by 128 publications

(121 citation statements)

References 22 publications

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“…Chemical armouring of the recycled concrete from the beginning of the column experiment until the alkalinity was exhausted (212 PVs) reduced the porosity of the column, which is similarly observed in several laboratory column and field studies on PRBs (Li et al, 2006;Kamolpornwijit et al, 2003;Furukawa et al, 2002;Wilkin et al, 2003).…”

Section: Mineral Precipitation and Changes In Physical Propertiessupporting

confidence: 60%

Permeable reactive barrier rejuvenation by alkaline wastewater

Banasiak

Indraratna

Lugg

et al. 2015

Environmental Geotechnics

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Chemical armouring of recycled concrete in a permeable reactive barrier (PRB) used for the neutralisation of acidic groundwater in acid sulfate soil terrain significantly decreases its acid neutralising capacity (ANC) by approximately 50% compared with its theoretical ANC. A long-term column test was conducted under simulated field groundwater conditions to assess the re-conditioning of armoured recycled concrete aggregates with alkaline wastewater, with the aim to restore and enhance the ANC and longevity of the PRB. The benefits of alkaline wastewater injection included sharp but short enhancement of the recycled concretes' ANC, as indicated by an increase in effluent pH (pH 3 to 7·7) and alkalinity (0 to 21·6 mM CaCO3) and a reduction in oxidation reduction potential (ORP,. While the results showed that the alkaline wastewater did not significantly reduce chemical armouring, it aided in the liberation of lodged mineral precipitates between concrete aggregates, reducing the severity of chemical and physical clogging. Batch tests demonstrated that, when exposed to acidic water, the ANC of recycled concrete pre-conditioned with alkaline wastewater was enhanced as indicated by higher pH, lower ORP and greater release of calcium (Ca2+) and alkalinity, compared to non-pre-conditioned concrete.

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Section: Mineral Precipitation and Changes In Physical Propertiessupporting

confidence: 60%

Permeable reactive barrier rejuvenation by alkaline wastewater

Banasiak

Indraratna

Lugg

et al. 2015

Environmental Geotechnics

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“…Several authors have reported that clogging may occur excessively near the inlet of the reactive materials and not homogeneously throughout the column (Kamolpornwijit et al 2003;Bilek 2006). Similarly, slightly larger amounts of precipitates formed towards the bottom half of column A (zones 1 and 2) rather than top half (zone 3) ( Table 2), showing that the precipitates were not distributed homogenously in the pore space and that their composition differed with distance along the column.…”

Section: Changes In Physical Propertiesmentioning

confidence: 97%

“…Several studies have reported that a major limitation of PRBs is not the exhaustion of the reactive material, but rather chemical armouring and clogging of the pore spaces through mineral precipitation and accumulation on the surface of the reactive media and within the pore spaces, respectively (Mackenzie et al 1999;Phillips et al 2000;Kamolpornwijit et al 2003;Li et al 2006). Column tests offer a controlled system in which to study the behaviour of armouring and clogging.…”

Section: Neutralisation Capacity/reactivitymentioning

confidence: 99%

Treatment of Acidic Groundwater in Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments

et al. 2011

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Acidic groundwater generated from pyrite oxidation in acid sulphate soil (ASS) is a major geoenvironmental problem in Australia. This study aims to evaluate recycled concrete as a reactive material in permeable reactive barriers (PRBs) for the remediation of acidic groundwater in lowlying ASS floodplains. Laboratory experiments were systematically conducted to investigate the acid neutralisation behaviour of recycled concrete and its potential to remove dissolved Al and Fe. The results confirmed that recycled concrete could effectively treat acidic groundwater from an ASS terrain, resulting in near-neutral effluent over a long period with complete removal of Al and Fe. The major mechanisms involved in neutralising acidic groundwater are thought to be the precipitation of Al and Fe as oxides, oxy-hydroxides and hydroxides. However, the accumulation of secondary minerals could decrease the reactivity of the recycled concrete. Indeed, chemical armouring could decrease the neutralising capacity of recycled concrete by up to 50% compared to the theoretical acid neutralisation capacity of this material. The results reported here also show that the neutralisation capacity and reactive efficiency of recycled concrete are dependent on not only the initial pH value but also the concentration of both Al and Fe in the acidic groundwater.

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“…Herbert, 2003;Kamolpornwijita et al, 2003;Mackenzie et al, 1999;Mayer et al, 2001Mayer et al, , 2006 has been the subject of much study, as preferential flow may lead to lower barrier performance than initially predicted. However, issues dealing with porosity decreases are generally restricted to zerovalent iron barriers (cf.…”

Section: Introductionmentioning

confidence: 99%

Implications of non-equilibrium transport in heterogeneous reactive barrier systems: Evidence from laboratory denitrification experiments

Herbert

2011

Journal of Contaminant Hydrology

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Organic substrates in reactive barrier systems are often heterogeneous material mixtures with relatively large contrasts in hydraulic conductivity and porosity over short distances. These short-range variations in material properties imply that preferential flow paths and diffusion between regions of higher and lower hydraulic conductivity may be important for treatment efficiency. This paper presents the results of a laboratory column experiment where denitrification is investigated using a heterogeneous reactive substrate (sawdust mixed with sewage sludge). Displacement experiments with a non-reactive solute at three different flow rates are used to estimate transport parameters using a dual porosity non-equilibrium model.

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Preferential flow path development and its influence on long-term PRB performance: column study

Cited by 128 publications

References 22 publications

Permeable reactive barrier rejuvenation by alkaline wastewater

Permeable reactive barrier rejuvenation by alkaline wastewater

Treatment of Acidic Groundwater in Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments

Implications of non-equilibrium transport in heterogeneous reactive barrier systems: Evidence from laboratory denitrification experiments

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