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PRBs in Germany■ Two R&D networks
(funded by the Federal Government)
“SAFIRA“ (6 Mio $) Basic R&D, semi-technical scalereactive materials for cVOCs/chlorobenzenes/PAHs
“RUBIN“ (4-5 Mio $) R&D and technical implementation of PRBs at different sites across the country
■ Public funds spent ≈ 14 Mio $ ■ Different private sites ≈ 6 Mio $
■ RUBIN project, volume: appr. 1.5 Mio $ (50 % public funds)
Bernau■ High contamination of cVOCs affecting two
aquifers (TCE up to around 100 mg/L)
■ Special reactor design capturing both aquifers by pumping GW and injecting itinto a collecting zone and additional tanks
■ Closed funnel = containment for the source and serving as a collecting/mixingzone for accumulating lifted GW before itenters the gate
■ RUBIN project, volume: appr. 1.5 Mio $ (50 % public funds)
Cut-off wallCut-off wall
Bracing Bracing
NE SW
Surface level
“Containment”
Inflow
Inflow
Reactor elements (modules) Drain
GWMS
Cut-off wall
18.30 m
2.30 m below s.l
4.50 m below s.l 5.50 m below s.l
8.0 m below s.l.
Reinfiltration
Bernau Elevation of the gate system
0 10 20 0 0 50 m
Top view of the funnel-and-gate
system 3 4
Bernau – PerformanceDecay of TCE
120000 Half life time of TCE according to column testing
100 mg/L
80000
50
0
40000
c(o) = 100 mg/L
Iron sponge (GG 0,3-2 mm)
0 280 min. 400 800 1200
Average retention time V/Vo: 8 V/Vo: 21 V/Vo: 34 V/Vo: 48 V/Vo: 64 V/Vo: 94 V/Vo: 114
Bernau – PerformanceTCE-Decay in the PRB
c(o)= 96,5 mg/L
0
25
50
75
100
R1 R2 R3 R4 R5 R6 R7 R8 R9 R10
[mg/
L]
Decay of cis-DCE and VC in the PRB; c(o)= 96,5 mg/L
0,00
0,05
0,10
0,15
0,20
0,25
R1 R2 R3 R4 R5 R6 R7 R8 R9 R10
[mg/
L]
c-DCE VC
0
1
100
R1 R2 R3 R4 R5 R6 R7 R8 R9 R10
[µm
ol/L
]
TCE c-DCE VC PCE
Concentration profiles of single components
- semi-logarithmic display -Field results (appr. after one
pore volume has been
exchanged)
Bitterfeld (“SAFIRA“) ■ Semi-technical test site for new PRB materials; five shafts(30 m deep, 3.50 m Ø)containing diff. steel reactors,loaded with different media: ■ Microaerophilic, anaerobicreactors (aquifer material) ■ Combined media, e.g.,GAC/microbiol.; ZVI/ORC) ■ Membrane- and zeolite-supported Palladium (Pd)■ Catalytic oxidation usingmetal catalysts; ultrasound
http://safira.ufz.de
Membrane-supported Pd/H2 rapidly dehalogenates monochlorobenzene (MCB) to benzene
Denkendorf
■ cVOC contamination (TCE, PCE, cis-DCE, 1,1,1-TCA, VC) is treated with GAC
■ “Drain-and-Gate” PRB to meet the low hydraulic gradient of 2%:
90 m long and 6 m deep gravel drainage directing the flow right towards a single GAC reactor
■ GAC reactor was placed inside a shaft (6 m deep)
Denkendorf
REWE-Mar kt
ESA Eppinger GmbH
Fa. Goldmann-Nörenberg
Körsch (
GWM12
0
Drainage
Reactor (shaft)
Rewe-Supermarkt
Areas of cVOC contamina
M2M3
M6
M8
BGW12 BGW11
GWM8
BGW 8
well
BGW 10
GWM13
BGW9
GWM2
GW M4 GWM3 BGW3
BGW 4
GWM10 GWM9 Spülschacht
GWM11
GW M7 GWM6
BGW13
BGW 7
GWM5
BGW5
UVB GW flow direction
street
creek
(creek)
Overview of the drain-and-gate system
West East South North
Aquitard
app. 90 m app. 60 m
Cohesive material
Filter gravel
Drainage tube (DN100)
Water table
Palladium on zeolite
3 m
Activated carbon
Outlet tube (DN150) Receiving water (Körsch)
Pump Water table
6 m
)
Denkendorf
RUBIN project: ■ Bypass: hydrogenation catalysts
like palladium on zeolite are tested
■ Addition of hydrogen gas:
fast and complete degradation of cVOCs (first, small column experiments in the first quarter of 2002: especially VC is effectively degraded, too)
Edenkoben
■ cVOCs (20% TCE, 50% cis-DCE, 30% 1,1,1-TCA)
■ 1998: pilot-scale F&G 2000: expanded to a full-scale F&G
■ Gates designed for a diverted, vertical flow inside Groundwater is passively lifted by avertical drainage (gravel columns) andthus directed through the ZVI bed
Edenkoben
■ Six identical gates, each constructed as a sheet pile caisson (open at its bottom)
■ Funnel: continuous sheet pile wall, 430 m long, 14 m deep
■ Funnel also runs through every gate, thus separating each of them into two chambers
■ Inside the gates the sheet pile wall was buried down to 1 m below the lowest groundwater level anticipated = overflow weir between the chambers
Karlsruhe
■ 2000/2001: full-scale F&G packed with granular activated carbon (GAC, 150 tons) to treat PAHs and BTEX
■ Funnel consists of sheet piles (200 m long, 17 m deep)
■ Eight gates consisting of specifically perforated steel; cylindrical steel tubes were lowered into previously set up, large diameter boreholes (2.5 m)
Karlsruhe
Overview of the full-scale F&G PRB
Former gas works plant
Karlsruhe
■ Pea gravel, serving as a filtermedium and for homogenizingthe flow through the gates,was packed at the inflow andoutflow zone
■ Free space left betweenthe steel tubes and the adjacent funnelsegments was sealedoff using clay
Clay seal
Pea gravel
Sheet pile wall Activated
carboninflow
outflowPerforated steel sheets
Karlsruhe
Sheet piles were pressed into the ground using the “silent piler”-technique
Packing the gate with granular activated carbon
Oberursel■ cVOC contamination treated with ZVI at
the BOSTIK site (TOTALFINAELF) ■ L-shaped F&G equipped with one gate ■ Gate shaped like a wide annulus:
◆ Diameter 3.3 m, 13 m deep ◆ Overlapping boreholes cast with
concrete forming the annulus(at the inflow/outflow zone, permeableconcrete was cast)
■ Funnel (slurry wall): 175 m long, 4-19 mdeep, 0.6 m thick
OberurselGate construction
Oberursel Gate construction, shape of the F&G