Innovative Site Investigation

Transcription

1 Workshop Monitored Natural Attenuation (MNA), Cracow, October 2009 Innovative Site Investigation Innovative Monitoring Dr. Weiss, Tübingen

2 Innovative Site Investigation Multilevel Sampling Passive Sampling New / Direct Push Wells Old / Conventional Wells

3 New / Direct Push Wells direct push sensors & sampling results decision sampling / installation Sensor Response depth [m] 4

4 New / Direct Push Wells Lost Pump System direct push casing Lost MPP Installation of a multilevel well, 20 m with 5 sampling ports lost point Bentonite Packer central tube for waterlevel measurements Minipressure Pump Probe rod ID 2 1/8 in.

5 MPP Mini Pressure Pump Low Flow Sampling sample line drive line valves filter Y-connector low flow sampling: flow rates of ml/min small design: 2,3cm x 23 cm easy in field: pneumatic controller and gas bottle e.g. nitrogen excellent for high volatile compounds e.g. BTEX, CHCs

6 New / Direct Push Wells 1-inch well double packer system sample line drive line pressure line MPP 1-inch packer 35 cm 1-inch packer filter pressure line 30 cm filter pressure line 1-inch packer ID: 2,5 cm 1-inch packer

7 New / Direct Push Wells: Ready to install wells Sand catcher Tubing with bentonite collars Filter section Direct Well Tubing 10 x 12/13 mm Spacer tubing: Prevent upper sand catcher from sliding up with tie rib Obligatory sand-bentonite catcher will prevent back fill material from falling down Quality Well In between lower and upper sand catcher: Optional sand catchers in homogeneous soils. Obligatory if clay layers and sand layers do alternate. Spacer tubing 16 x 20 mm Sand catcher Filter section of DirectWell

8 New / Direct Push Wells: Multi Channel Wells CMT-System 7-Channel 3-Channel 2 cm Port 1 Port 2 Port 3

9 New / Direct Push Wells: Multi Channel Wells Zeitz 2005 Frankfurt Frankfurt, Berlin 2006 Frankfurt 2007 Ghent, 2007 Bonn 2008 Berlin 2009

10 Old / Conventional Wells: Multilevel Sock-Packersystem inner & outer packermembrane pressure & sampling tubing MPPs filter screen gravel pack Parallel low flow sampling in different depths Modular construction: different diameters, legth and number of sampling ports Mobile and/or half-stationary system Easy to handle installation and deistallation

11 Old / Conventional Wells: Multilevel Sock-Packersystem mbgl lithology well pump depth [m bgl] conductivity [µs/cm] Monochlorobenzene [µg/l] Benzene [µg/l] 5,0 10,0 1) 12, ,0 2) 15, ,0 3) 17, ) 21, ,0 30,0 5) 27, ,0 6) 7) 32,0 33, ,0 8) 37, ,0 9) 10) 41,0 44, ,0 11) 48, ,0

12 Old / Conventional Wells: Multilevel Washer-Packersystem Parallel low flow sampling in different depths Modular construction: different diameters, legth and number of sampling ports Mobile and/or half-stationary system Easy to handle installation and deistallation

13 Old / Conventional Wells: Comparison: Conventionell Double Packer with ML Washer-Packer and ML Sock-Packer m bgl 5,5 6,5 7,5 8,5 Perchloroethylene Double Packer ML Washer-Packer ML Sock-Packer sample line 9,5 pump 10,5 11,5 12,5 packer 13, [µg/l] KORA, Karlsruhe-Ost/Killisfeld Wickert,F.,Müller,A.,Schäfer,W.&Tiehm,A.: Altlastenforum,1,2006

14 Passive Sampling Generally principle of water sampling Surface- and groundwater active passive

15 Passive Sampling Advantages compared to conventionell active monitoring No power supply or heavy and bulky equipment necessary No limitations through depth No disposal of conatminant water Small effort for sampling, transport, cooling and storing of the samples No filtration necessary No losses through sorption to pump tubing and sampling vessels No or little losses of high volatile compounds during sampling process No danger of cross contamination No influence regarding the hydraulic flow situation of groundwater concentration?? Active snap shot sampling passive sampling TWA Detectability through accumulation??? time Time-weighted average (TWA) of concentration fluctuations

16 Passive Sampling Example: PDB Equilibrium Sampler (Polyethylene-Diffusion-Bag-Sampler) Design PE-membrane, Ø: 3-5 cm x L: cm, filled with deinonized water (ca. 300 ml) Exposure time minimum 2 weeks Substances High volatile organic compounds VOCs: BTEX, CHCs Analysis Conventional water analysis Standard sampler since 2001 in the US (US-EPA)

17 Passive Sampling Example: Ceramic Dosimeter TWA Sampler Design Ceramic tube/membrane: Ø: 1 cm x L: 4.5 cm, effective pore size 5 nm, pore volume 30.5 % Adsorbent: IRA-Amberlite 743: PAHs Dowex Optipore L-493: BTEX, CHCs, Heterocycl. Caps: PTFE Exposure time weeks -months Substances PAHs, BTEX, CHCs, Heterocycles Analysis Conventional solvent extraction Result TWA: Time Weighted Average concentration

18 Passive Sampling Results: Ceramic Dosimeter TWA Sampler water conc. [µg/l] naphthalene well A conventional water samples triplicate conventional water samples average dosimeter time [d] dosimeter average [Martin et al. 2003, ES&T 37, 1360] good reproducibility of the method; nap 19.9 ± 3.4 µg/l

19 Innovative Site Investigation Representative Sampling Volume volume based Active point based Passive point based => integral => depth specific => TWA Low Flow L/sec ml/min????? time

20 Workshop Monitored Natural Attenuation (MNA), Cracow, October 2009 Innovative Site Investigation Multilevel Sampling Passive Sampling