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