Sequenced Permeable Reactive Barrier for the Pretreatment of Nitrate and Remediation of Trichloroethene - Permeable Reactive Barrier: Sustainable Groundwater Remediation - page 109

7
Sequenced Permeable Reactive Barrier for
the Pretreatment of Nitrate and Remediation
of Trichloro ethene
Keely Mundle, Janet Macmillan, and Ben McCarthy
CONTENTS
7.1 Introduction ................................................................................................ 109
7.2 WCS Site Description ................................................................................ 111
7.3 ZVI Bench-Scale Tests ............................................................................... 115
7.4 Field Investigation...................................................................................... 116
7.5 Denitrification Bench-Scale Tests ............................................................ 117
7.6 Implementation .......................................................................................... 122
7.7 Results ......................................................................................................... 124
7.8 Groundwater .............................................................................................. 125
7.9 Nitrate Concentrations .............................................................................. 127
7.10 Chlorinated Solvent Concentrations ....................................................... 128
7.11 Eh and pH ................................................................................................... 131
7.12 Summary ..................................................................................................... 131
Acknowledgments .............................................................................................. 132
References ............................................................................................................. 133
7.1 Introduction
Dense nonaqueous phase liquids (DNAPLs) such as chlorinated solvents,
polychlorinated biphenyl (PCB) oils, creosote, and coal tar, when released to
the subsurface, will distribute themselves in the form of both pools of higher
saturation distributions and disconnected blobs and ganglia of organic liq-
uid referred to as residual. The longevity of residual and pooled DNAPL in
porous media will be governed by a variety of factors, including the ground-
water velocity and the aqueous solubility of the DNAPL components.
Complete source removal of DNAPL can be difficult and costly, and partial
source removal may not have a significant impact on the extent of the plume
but may reduce the longevity of the plume (Falta et al. 2005). Treatment of
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