Environmental Engineering Reference
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was below 30 mg/L. The groundwater exhibited very high carbonate hard-
ness due to the abundant red and shelly limestone in the area. Sulfate levels
were determined at 200 mg/L. The low hydraulic gradient of 2% prompted
to design a full-scale D&G PRB that catches (collects) and drains the con-
taminated groundwater passively by means of a 90-m-long gravel drain
equipped with additional filter pipes. The drain directs the groundwater
toward a reactor loaded with GAC. The depth of the PRB is about 6 m. The
Denkendorf D&G reactor was constructed as a shaft-shaped structure (ISV)
employing standard civil-engineering techniques. The system meets its
remediation goal of 10 μg/L cVOCs.
A bypass from the passively drained groundwater flow into the reactor
was installed to test innovative reactive materials such as palladium on zeo-
lite (palladium loading: 0.5% (w/w)) directly inside the shaft under field con-
ditions. Investigations were implemented by a member project of the RUBIN
R&D program (Burmeier et al., 2006). The catalyst had a “molecular design”
(due to its “zeolite back bone” wherein the palladium was finely dispersed
in three-dimensional (3D), molecular canals). This design was supposed to
prevent sulfides from poisoning the palladium, being a frequent, serious
problem when palladium is used in contaminated groundwater comprising
relatively high sulfate concentrations (Birke et al., 2003, 2007; Parbs and Birke,
2005). Different other designs and types of catalysts had also been success-
fully tested using the bypass at the D&G PRB between 2007 and 2012 (Birke
and Burmeier, 2012a,b).
13.2.2.4 Edenkoben
Set up in 1998 (pilot scale), extended to full scale in 2000. Type: F&G (six
gates), restricted accessibility to the gates, ZVI for cVOC degradation. For
detailed design features, see Rochmes and Woll (1998), Rochmes (2000), and
Birke et al. (2003).
A groundwater contamination by cVOCs at Edenkoben was attributed to
the former use of CHC solvents for production processes on-site. Several hot
spots were found on the property, partly situated below some buildings. A
heterogeneous cVOC plume that was more than 400 m wide, originating by at
least three individual, partly overlapping plumes, was identified. These indi-
vidual plumes contained different contaminants at varying concentrations.
For example, the southern plume chiefly consisted of TCE and cis-DCE to a
total of 8000 μg/L cVOCs. The middle plume comprised 1,1,1-TCA, TCE, and
cis-DCE (up to 20,000 μg/L cVOCs), whereas the northern plume was con-
taminated predominantly by PCE (≈ 2000 μg/L cVOCs). The average compo-
sition of cVOCs was 20% TCE, 50% cis-DCE, and 30% 1,1,1-TCA. The geology
was characterized by infills and a highly heterogeneous sedimentology (silty
overlying strata, 1-6 m thick). Two relevant aquifers had to be taken into
account, the lower aquifer being nonpolluted. The polluted upper aquifer was
split into two permeable layers, separated by silt and silt-sand strata varying
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