Ten Year Performance Evaluation of a Field-Scale Zero-Valent Iron Permeable Reactive Barrier Installed to Remediate Trichloroethene Contaminated Groundwater

Abstract

The Monkstown zero-valent iron permeable reactive barrier (ZVI PRB), Europe's oldest commercially-installed ZVI PRB, had been treating trichloroethene (TCE) contaminated groundwater for about 10 years on the Nortel Network site in Northern Ireland when cores from the reactive zone were collected in December, 2006. Groundwater data from 2001-2006 indicated that TCE is still being remediated to below detection limits as the contaminated groundwater flows through the PRB. Ca and Fe carbonates, crystalline and amorphous Fe sulfides, and Fe (hydr)oxides have precipitated in the granular ZVI material in the PRB. The greatest variety of minerals is associated with a approximately 1-2 cm thick, slightly cemented crust on top (up-gradient influent entrance) of the ZVI section of the PRB and also with the discontinuous cemented ZVI material ( approximately 23 cm thick) directly below it. The greatest presence of microbial communities also occurred in the up-gradient influent portion of the PRB compared to its down-gradient effluent section, with the latter possibly due to less favorable conditions (i.e., high pH, low oxygen) for microbial growth. The ZVI filings in the down-gradient effluent section of the PRB have a projected life span of >10 years compared with ZVI filings from the continuous to discontinuous cemented up-gradient ZVI section (upper approximately 25 cm) of the PRB, which may have a life span of only approximately 2-5 more years. Supporting Information from applied, multi-tracer testing indicated that restricted groundwater flow is occurring in the upper approximately 25 cm of the ZVI section and preferential pathways have also formed in this PRB over its 10 years of operation.

Sustainable Zero-Valent Metal (ZVM) Water Treatment Associated with Diffusion, Infiltration, Abstraction, and Recirculation

“…the creation of permeable reactive barriers (PRB) containing n-ZVM (e.g., a physical static barrier within the aquifer containing n-ZVM) [5,[8][9][10][11][12][13][14][15]] and 2. the injection of n-ZVM into an aquifer with injected or infiltrating water [6,7,16,17].…”

“…Sustainable Zero-Valent Metal (ZVM) water treatment associated with infiltration, abstraction, and recirculation removes metals (including As), nitrates, chloro-organics, sulphates, phosphates, organic chemicals) from water in the aquifer/GWM (or during abstraction/infiltration). ZVM treatment is experimental [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], but offers the potential to treat storm runoff, abstracted water and water within an aquifer. The experimental focus has been to identify if n-ZVM treatment actually reduces pollutants Where the ZVM treatment is effective the experimental studies have sought to identify the kinetic parameters associated with pollutant removal [5], i.e., the relationship between temperature and the rate of pollutant removal.…”

Reactive Transport Modeling for Mobilization of Arsenic in a Sediment Downgradient from an Iron Permeable Reactive Barrier

“…PRBs have been proven to be effective not only for inorganic contaminants including arsenic [15][16][17][18], but also for many organic contaminants [19,20]. Particularly, granular iron (commonly referred as zero-valent iron (ZVI)) has been the most commonly used reactive material in PRBs.…”

Evidences of in Situ Remediation from Long Term Monitoring Data at a TCE-contaminated Site, Wonju, Korea

“…Vol. 18(6), p. 8~17, 2013 term effectiveness of remediation techniques (McGuire et al, 2004;McGuire et al, 2006;Phillips et al, 2010). Previous studies have assessed the remediation efficiency based on the monitoring data, most of which were obtained from near-source zones.…”