The Membrane Interface Probe

Some ins and outs

2

Program

The Membrane Interface ProbeStandard Practise (ASTM D7352-07)Direct push machines (Geoprobe and CPT)

MIP ≠MIP Influences and detection limits

MIP Detectors• FID (Flame Ionization Detector)

Corg.

• PID (Photo Ionization Detector)Ionization Potential < 10,6 eV

• DELCD (Dry Electrolytic Conductivity Detector)Organic Bonded Chlorine (VOCL)

MIP (Membrane Interface Probe)

MIP• Semi-quantitative VOC detection, primarily

VOCL and BTEX, in both vadose and saturated zone

• Simultaneous logging of geological, hydrogeological and chemical subsurface properties.

• Digital data recording

• Measurement range from 300 ppb – NAPL

• Precise 3D delineation of source and plume areas – supports on-site decision-making

Project:

Test Location:

Client:

Processed by:

Test Date:

Contractor: Y-Coord.:

X-Coord.:

Level:

Depth:

Legend (Colors in Friction Ratio Profile)

1 Sensitive, fine grained

2 Organic soils, peat

3 Clay

4 Clay to silty clay

5 Clayey silt to silty clay

6 Sandy silt to clayey silt

7 Silty sand to sandy silt

8 Sand to silty sand

9 Coarse to medium sand

10 Gravel to gravelly sand

11 Very stiff, fine grained

12 Very stiff sand to clayey sand

Soil types 11 und 12 are heavily overconsolidated or cemented.

Depth

in m

bgs.

0 1 2 3 4 5 6 7 8 9 10

Friction Ratio in %

0,1

1,0

10,0

100,0

Con

e R

esis

tanc

e in

MP

a

1 2

34

56

78

910

1112

MIP1

MIP1

0 10 20 30 40 50 60 70

Cone Resistance [MPa]

0 2 4 6 8 10

Friction Ratio [%]-Conductivity [mS/m*3,5]

Robertson CPT Soil Classification (modified)

0 1 2 3 4 5 6 7 8 9 10

Friction Ratio in %

0,1

1,0

10,0

100,0

Con

e R

esis

tanc

e in

MP

a

01

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

01

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

0,0 0,2 0,4 0,6 0,8 1,0

DELCD [V]

0,0 0,1 0,2 0,3 0,4 0,5

PID [V]

0,0 0,2 0,4 0,6 0,8 1,0

FID [V]

0,010,01 0,10 1,00

DELCD [V]

5

10

15

20

25

30

35

Tie

fe in

m u

. GO

K

loose

very dense

dense

medium dense

very loose

Soil Density and Consistency (interpreted)

Legend (Colors in Cone Resistance Profile)

FUGRO CONSULT GMBHIn-Situ Technologies

Ehlbeek 15 A

Tel. +49 5139 9894-0, Fax +49 5139 895709

D-30938 Burgwedel

soft

very stiff

stiff

firm

very soft

hard

Depth

in m

bgs.

1 - 10 mg/l > 100 mg/l

50 - 100 mg/l

10 - 50 mg/l

0,3 - 1,0 mg/l

Legend (Colors in DELCD Profile)

Estimated VOCL-Concentrationin PCE-Equivalents

Standard Operating procedure

ASTM D 7352-07 Geoprobe Standard Operating Procedure MIP

Provide consultants with a better understanding of how MIP works and what should be reported in a field report!

Information in a fieldreport Site information Data and time MIP-log is obtained MIP contractor, field technician and assistants File name of MIP-logging location and depth of

final penetration. File name of the pre-log response test along

with compound used and concentration. File name of the post-log response test

along with compound used and concentration.

Equipment used in the investigation. Site and locations specific info.

Direct push machines

Mobile In Situ Techniques

Direct push machines

GEOPROBE 6610DT 20t-Minicrawler Stand-Alone-CPT-Rig (15 t)

MIP ≠MIP MIP technology is >15 years old.

Several MIP-service providers have made adjustments to their system.

Geoprobe has developed system as well.

MIP technique is still being improved (Enissa MIP)

All systems are still on the market so MIP ≠MIP!!

11

Membrane Interface Probe : influences

Temperature membrane block (70 tot 130 °C) Membrane :Quality is never the same, not with new membranes but

certainly not when used. Trunkline (used material, length, temperature of cable can heat the

transport line) Detectors (FID, PID, DELCD great difference in quality and stability

- PID : needs to be cleaned regularly for a stable baseline- DELCD : central electrode may shift resulting in a false positive signal

only on DELCD Gasses : H2S can give a respons on the DELCD!

CH4 can cause quenching on PID and DELCD geven. Lithology and type of contamination. High concentration : carry over on detectors, contamination of membrane

and trunk line. Heated trunk-line and being able to better heat the membrane block can minimize the effect.

They all affect the detection limits

Some examples

MIP detection limits by VITO (2008)Detection limits mentioned by Geoprobe and service providers.

13

Detection limits according to Belgium’s VITO 02.2008

(OLD MIP-system)

Detection limit can be much lower

Contamination MIP-respons (mV)

Verification with BAT-sample

Verification with tradition sampling

BTEX 20 mV on PID 40 μg/l (BTEX) < 0,1 μg/l

VOCl 10 mV on DELCD

123μg/l (per + tri) --

VOCl 10 mV on DELCD

80 μg/l (per + tri) < 0,1 μg/l

VOCl 15 mV on DELCD

105 μg/l (per + tri)

--

VOCl 90 mV on DELCD

4290μg/l (per) 3300 ug/l

15

“Detection” limits MIP in the field PER : 300 µg/l

Tri : 300 µg/l CIS : 300 µg/l VC : 400 µg/l

BTEX 300-500 µg/l

Enissa MIP (1-10 µg/l) will be presented later on

Note : External factors have a strong influence on the detection limit. These are just a indication and can be higher or lower depending on teh external factors.

MIP is a screening tool, always take samples for verification.

MIP developments

Developments of the last 15 yearsRecent development (Enissa MIP)

• Heated MIP trunk line provides higher sensitivity (sharper peaks, reduced tailing, detection range includes SVOC)

• Membrane temperatures between 120 and 130 C in the saturated zone (increased thermodesorption leads to higher sensitivity)

• Simultaneous CPT-EC logging can give indication on preferential pathways or NAPL presence

• More stable and other detectors (FID, PID, DELCD, ECD, XSD)

MIP improvements past 15 years

Enissa MIP EnISSA MIP: MIP with dedicated GC-MS detection

combined with proprietary contaminant sampling technology

Notes for interpretationAre the data coming from a comparable MIP-system

Watch the membrane temperatureBe ware of carry overBe ware of quenching of detectorsCompare pre- and post-log response test, they should be comparable

Remember which detectors should respond to your contaminant, do they all respond???

Discussion / remarks