Monitoring the removal of phosphate from ground water discharging through a pond-bottom permeable reactive barrier

Ground Water Monitoring and Remediation
By: , and 

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Abstract

Installation of a permeable reactive barrier to intercept a phosphate (PO4) plume where it discharges to a pond provided an opportunity to develop and test methods for monitoring the barrier’s performance in the shallow pond‐bottom sediments. The barrier is composed of zero‐valent‐iron mixed with the native sediments to a 0.6‐m depth over a 1100‐m2 area. Permanent suction, diffusion, and seepage samplers were installed to monitor PO4 and other chemical species along vertical transects through the barrier and horizontal transects below and near the top of the barrier. Analysis of pore water sampled at about 3‐cm vertical intervals by using multilevel diffusion and suction samplers indicated steep decreases in PO4 concentrations in ground water flowing upward through the barrier. Samples from vertically aligned pairs of horizontal multiport suction samplers also indicated substantial decreases in PO4 concentrations and lateral shifts in the plume’s discharge area as a result of varying pond stage. Measurements from Lee‐style seepage meters indicated substantially decreased PO4 concentrations in discharging ground water in the treated area; temporal trends in water flux were related to pond stage. The advantages and limitations of each sampling device are described. Preliminary analysis of the first 2 years of data indicates that the barrier reduced PO4 flux by as much as 95%.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Monitoring the removal of phosphate from ground water discharging through a pond-bottom permeable reactive barrier
Series title Ground Water Monitoring and Remediation
DOI 10.1111/j.1745-6592.2009.01235.x
Volume 29
Issue 2
Year Published 2009
Language English
Publisher Wiley
Contributing office(s) New England Water Science Center, Toxic Substances Hydrology Program
Description 13 p.
First page 43
Last page 55