Permeable Reactive Barriers in Europe - Permeable Reactive Barrier: Sustainable Groundwater Remediation - page 293

16 EPA-PAH

Gates 1, 2, 3
effluent concentration
<1% of influent

N,S,O-
heterocycles
Other PAH
BTEX, indane,
indene, TMB

Sum each: <LOD

11%
21%

29%

Gate 1
influent

8%

Gate 3
influent

8% 68%

5%

41%

7%

Sum: 5 μg/L

22%

Gate 2
influent

Sum: 53 μg/L

80%

31%
B9808

Sum: 5594 μg/L

40%

20%

9%

Sum: 1175 μg/L

FIGURE 13.7
Aerial view and overview of the cleanup performance of the GAC-PRB at Brunn am Gebirge,
Austria, according to recently recorded monitoring data (gained between 2007 and 2009, aver-
age values). Therefore, this PRB has been showing very good cleanup results since its erection
in 1999. (Courtesy of Leuphana University of Lueneburg, Professor Dr. W. Ruck, Dr. W. Palm.)

The decontaminated groundwater is released from each reactor by means
of a pipe that penetrates the barrier and is directed to another shaft down-
stream the barrier, where it is collected from all four reactors and mingled.
Inside this shaft, monitoring is performed to validate the cleanup efficiency
of the system. Design costs amounted to 100,000 $, and installation and con-
struction came at 650,000 $. An additional investigation of the long-term
behavior of the system is performed as part of the PEREBAR project of the
European Community (PEREBAR, 2014). Protecting the GAC reactors from
intruding oxygen helps avoid aerobic microbiological activity. A careful
selection of materials for those parts that could come into contact with the
groundwater and the reactor material is essential. Throughout around 15
years of operation, the regular monitoring has been verifying that all con-
taminants have been below detection limits (Figure 13.7).

13.3.2 Willisau

Set up in spring 2004, type: hanging CRB (full-scale, nonoverlapping large-
diameter boreholes in two rows), ZVI is used for reductive chemical fixation
of Cr VI , and the first results gathered in 2005 proved an efficient removal of
Cr VI . Instead of a conventional continuous barrier, this PRB consists of large
diameter cyclindrical boreholes (piles) installed in rows: a single row for
lower Cr VI concentrations and an offset double row for higher Cr VI concentra-
tions. The large diameter cyclindrical boreholes are filled with reactive cast