Sequenced Permeable Reactive Barrier for the Pretreatment of Nitrate and Remediation of Trichloroethene - Permeable Reactive Barrier: Sustainable Groundwater Remediation - page 117

7.5

1400
2000
1300

<1 <1

<1
<1
<1

450
1100

61

36

5.0

5
9
12

2.5

750
41

100 µg/L

10 2

Transition zone

0.0

5

40

Inferred clay

-2.5

Leederville formation

<1

-5.0

A A'

Southwest Northeast

Wellscreen TCE
concentration

0510 meters 5

(µg/L)

FIGURE 7.3
TCE concentrations along the proposed PRB alignment.

7.5

4.5

1.5
1.3

<0.01

3.9

5.0

13
7.2
0.83

7.5
5.9

12
14
14

2.5

1 mg/L 5

Transition zone

1.9

0.0 8.9

Inferred clay

-2.5

Leederville formation

-5.0

A A'

Southwest Northeast

Wellscreen NO -
concentration

0510 meters 5

(mg/L)

FIGURE 7.4
Nitrate concentrations along the proposed PRB alignment.

7.5 Denitrification Bench-Scale Tests
Owing to the level of nitrate concentrations detected in groundwater, an
upgradient denitrification PRB to pretreat the groundwater was proposed.
To minimize potential passivation of ZVI by organic carbon, it was suggested
that the most suitable media for the denitrification PRB would be a relatively
degraded carbon source that is not overly labile (J. Vogan, 2009, pers. comm.).