Environmental Engineering Reference
In-Depth Information
11.3.4.3 Reactive Barrier in Brunn am Gebirge (Austria) ........ 243
11.4 Conclusions ................................................................................................. 243
Acknowledgments .............................................................................................. 245
References ............................................................................................................. 246
11.1 Introduction
Permeable reactive barriers (PRBs) are alternatives to common active
groundwater remediation technologies including those based on pump and
treat [1-5]. PRB is a passive in situ groundwater remediation technique that
avoids several inherent technical drawbacks of active systems a priori. A
PRB is defined as an in situ method for remediating contaminated ground-
water which combines a passive chemical or biological treatment zone with
subsurface fluid flow management [6]. PRBs that were first installed in the
United States in the early 1990s used zero-valent iron (e.g., elementary iron).
Due to the inability of iron (Fe) to efficiently remediate polycyclic aromatic
hydrocarbons (PAHs), for the past 15 years, activated carbon has been used
in PRBs as an additional adsorbent for PAHs and other related organic com-
pounds [7,8].
Commencing in 2000, the Federal Ministry of Education and Research
in Germany (BMBF) funded the project RUBIN (“Reaktionswände und
-barrieren im Netzwerkverbund” (German Permeable Reactive Barrier
Network)). The second stage of the project RUBIN II, was launched in 2006
[9]. At the same time, a different view and philosophy of remediation tech-
niques excluding human intervention led to the development and trial of the
concept of natural attenuation. The application of natural attenuation to the
remediation of NSO-heterocycles (for instance in tar oil-contaminated areas)
was investigated in Germany within the project KORA (“Kontrollierter
natürlicher Rückhalt und Abbau von Schadstoffen bei der Sanierung kon-
taminierter Grundwässer und Böden” (Retention and Degradation Processes
to Reduce Contaminants in Groundwater and Soil)) [10] that was also funded
by the BMBF.
Basic concepts for the analysis of PAHs and NSO-heterocycles were devel-
oped within the framework of the KORA project. However, most of the results
presented here that relate to the efficiency of activated carbons in PRBs to
remediate NSO-heterocycles were obtained within Subproject 3 of RUBIN II.
11.1.1 Solubility of NSO-Heterocycles and Their Parent Aromatics
The derivation of innovative methods for the analysis of hydrophobic com-
pounds such as the classical 16 EPA-PAHs or phenols and highly polar
compounds such as N-heterocycles (N-HETs) is necessary due to the
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