Sequenced Permeable Reactive Barrier for the Pretreatment of Nitrate and Remediation of Trichloroethene - Permeable Reactive Barrier: Sustainable Groundwater Remediation - page 129

12

1

Jul-10
Nov-10
Feb-11
Jun-11
Dec-11
Mar-12
Jun-12
Sep-12

0.8

0.6

0.4

0.2

0

MWG107B
Upgradient

MWG101B
Denit. PRB

MWG112B
between

MWG104B
ZVI PRB

MWG110B
Downgradient

Monitoring well

FIGURE 7.13
TCE concentrations along cross-section C-C′ for B series monitoring wells.

1.4

1.2

Jul-10
Nov-10
Feb-11
Jun-11
Dec-11
Mar-12
Jun-12
Sep-12

1

0.8

0.6

0.4

0.2

0

MWG107B
Upgradient

MWG101B
Denit. PRB

MWG112B
between

MWG104B
ZVI PRB

MWG110B
Downgradient

Monitoring well

FIGURE 7.14
DCE concentrations along cross-section C-C′ for B series monitoring wells.

the PRBs have been underestimating the concentrations of chlorinated eth-
enes. Rebounding concentrations may result from desorption of chlorinated
solvents from soil (Geosyntec 2007, Sale and Newell 2011). Underestimations of
the concentrations of chlorinated ethenes could result from sorption to media
or be related to issues with well construction or sampling techniques. In an