RemTech 2006 Banff, Alberta

Transcription

1 Use f Laser Induced Flurescence (LIF), il/lnapl Labratry Testing, Mdeling and Actual Recvery Data t Evaluate LNAPL Mbility, tability and Recverability RemTech 2006 Banff, Alberta Matthew C. Russeau, Cnestga-Rvers & Assciates Ltd. David J. Cushman, Cnestga-Rvers & Assciates Ltd. Gavin O Neill, O Cnestga-Rvers & Assciates Ltd. Rbert W. Hare, General Mtrs Crpratin

2 Case tudy - Backgrund ubject ite 600 acre General Mtrs Crpratin (GM) manufacturing facility in the U..; uth prtin f ite (apprximately 100 acres) leased t a 3rd party and underging redevelpment fr the cnstructin f an 800,000 square ft building; Area referred t as Area f Industrial Redevelpment (AIR).

3 ite / AIR / LNAPL Areas AIR

4 Backgrund (Cnt d) LNAPL was discvered in varius areas in the AIR, including an area which in part, was lcated beneath the prpsed building ftprint; An aggressive LNAPL recvery prgram was implemented in the ftprint area in supprt f the cnstructin schedule in the AIR (refer t Cushman et al., RemTech 2006); and This paper fcuses n the LNAPL mbility and recverability evaluatin cnducted in the remaining LNAPL areas within the AIR.

5 Gelgy/Hydrgelgy Gelgy is cmprised f lw permeability glacial sils (silts and clays with ccasinal sand seams) with several areas f sand fill material; Depth t air/lnapl interface varies frm apprximately 15 t 30 feet bgs; LNAPL thicknesses vary frm a sheen t 12 feet; and LNAPL has been fingerprinted as a weathered N. 2 fuel il/diesel with lesser amunts f N. 6 fuel il.

6 LNAPL Mbility Evaluatin Methdlgy Cnducted Laser Induced Flurescence (LIF) survey using Rapid Optical creening Tl (ROT) technlgy; Cllected undisturbed sil cres in select lcatins f sil znes exhibiting varying degrees f relative flurescence during ROT (greatest t least); ubmitted sil cres fr labratry phtgraphy and testing f key LNAPL mbility parameters;

7 LNAPL Mbility Evaluatin Methdlgy (Cntinued) Cmpared labratry measured LNAPL saturatin and crrespnding residual saturatin values t qualitatively evaluate inherent mbility ptential; Calculated maximum LNAPL relative permeability, cnductivity, mbility and velcity values fr each sample lcatin using API/Charbeneau methds; and Cmpared calculated LNAPL velcities t de minimis mbility threshld fr LNAPL*.

8 De Minimis Minimis LNAPL Velcity* It has been suggested that an LNAPL velcity f 1 x 10-6 cm/s r less, represents the de minimis mbility threshld fr LNAPL (ATM, 2005); This threshld plays a critical rle in LNAPL mbility evaluatins and the ptential need fr active recvery systems.

9 LNAPL Delineatin Cnventinal vs. Innvative Cnventinal Delineatin Cnventinal LNAPL delineatin accmplished using varius cnventinal drilling/direct push methds including hllw stem auger, rtsnic, and Geprbe; il screening fr LNAPL accmplished using visual and lfactry techniques, field screening (PID, UV light, shake tests, Oilcreenil-udan udan IV); Wells installed in areas with high ptential fr LNAPL based n sil screening.

10 LNAPL Delineatin Cnventinal vs. Innvative

11 LNAPL Delineatin Cnventinal vs. Innvative phisticated Delineatin Advanced 128 ROT pints thrughut AIR; ROT cnducted using special Cne Penetratin Testing (CPT) rig. il classificatin based n resistance and frictin t CPT prbe during penetratin thrugh grund; CPT prbe equipped with laser/sapphire windw assembly;

12 LNAPL Delineatin Cnventinal vs. Innvative phisticated Delineatin As prbe is advanced, laser light is directed thrugh the windw and int the subsurface; Laser light is absrbed by the armatic hydrcarbn mlecules which causes the mlecules t fluresce; A prtin f the flurescence is reflected thrugh the sapphire windw and returned via fibre ptic cable t the detectin system in the CPT rig;

13 LNAPL Delineatin Cnventinal vs. Innvative phisticated Delineatin The emissin data frm the pulsed laser light is averaged int ne reading per secnd intervals and is recrded cntinuusly; Intensity f flurescence is quantified via cmparisn against a standard hydrcarbn mixture used t calibrate laser; The intensity f the flurescence is prprtinal t the amunt f hydrcarbn present.

14 LNAPL Delineatin Cnventinal vs. Innvative LIF site investigatin technique verview urce: Dakta Technlgies, Inc.

15 LNAPL Delineatin Cnventinal vs. Innvative ROT utput frm subject site investigatin

16 LNAPL Delineatin Cnventinal vs. Innvative Maximum ROT Intensity Plan View

17 LNAPL Delineatin Cnventinal vs. Innvative Averaged (1-ft thick) ROT Plan View

18 il Cre Lcatins Based n ROT results, 24 brings were advanced and undisturbed helby Tube sil cres cllected frm areas shwn t be LNAPL impacted; 7 lcatins were deemed t be the mst impacted with LNAPL based n ROT relative flurescence readings; 17 lcatins were deemed t be less impacted t evaluate areas f lesser saturatin and LNAPL fringe areas.

19 Cre Phtgraphy il cres submitted fr cre phtgraphy in bth white light and ultravilet (UV) light; LNAPL, when expsed t UV light, fluresces; Intensity f flurescence crrespnds t amunt f LNAPL; Lighter end hydrcarbns (gasline/kersene) tend t fluresce white/blue; middle ends yellw/gld; and heavy ends red/brwn.

20 Cre Phtgraphy

21 Labratry Testing f LNAPL Mbility Parameters Discrete sil znes (0.2 ) ) f maximum UV flurescence (based n qualitative assessment f cre phts crss-referenced referenced with ROT results) were submitted fr testing f the fllwing parameters: - LNAPL saturatin and residual saturatin; - sil grain size analysis, ttal prsity Water/LNAPL samples submitted fr testing f density, viscsity and interfacial tensins.

22 ummary f ROT / Lab Results

23 LNAPL aturatin vs. Residual aturatin LNAPL saturatins measured using API RP 40 (Dean- tark); LNAPL residual saturatins measured using ATM D425M, Dean-tark (centrifugal test) and ATM D6836 (drainage/imbibitin imbibitin capillary pressure test); Results indicated that all 24 lcatins abve residual saturatin; Only 4 lcatins were mre than 25% abve residual saturatin (based n mre cnservative centrifugal test).

24 ROT / LNAPL aturatin Crrelatin Pltted ROT flurescence respnse against labratry measured LNAPL saturatin t see if a strng crrelatin culd be established fr the LNAPL areas; Achieved R 2 values f 0.90 fr first area, 0.86 fr secnd area, and 0.95 fr third area with an verall crrelatin f 0.74 (Nte: il types in each area are relatively cnsistent); and Results suggest that LNAPL saturatins may be calculated fr all 127 ROT pints based n these relatinships.

25 ROT / LNAPL aturatin Crrelatin LNAPL aturatin vs. Average ROT Flurescence - LNAPL Area 1/2 (Cmparing the same 0.2' Vertical Intervals) LNAPL aturatin vs. Average ROT Flurescence - LNAPL Area 9/10 (Cmparing the same 0.2' Vertical Intervals) LNAPL aturatin % y = x R 2 = ROT Flurescence % Respnse LNAPL aturatin % y = x R 2 = ROT Flurescence % Respnse LNAPL aturatin vs. Average ROT Flurescence - LNAPL Area 11 (Cmparing the same 0.2' Vertical Intervals) LNAPL aturatin vs. Average ROT Flurescence - All Areas Cmbined (Cmparing the same 0.2' Vertical Intervals) LNAPL aturatin % y = x R 2 = ROT Flurescence % Respnse LNAPL aturatin % y = x R 2 = ROT Flurescence % Respnse

26 LNAPL Mbility Calculatins (API, 2004) LNAPL mbility is expressed as: T M = V Where: M V T = inherent il mbility (ft/day) = specific il vlume per unit area (ft 3 /ft 2 ) = il transmissivity (ft 2 /day)

27 LNAPL Mbility Calculatins LNAPL Mbility Calculatins (API, 2004) (API, 2004) = 2 1 z z dz V φ b V φ = = 2 1 z z w r w w dz K k T μ μ ρ ρ K T = b K b K b M φ φ = =

28 LNAPL Mbility Calculatins (API, 2003) Typical LNAPL aturatin and Relative Permeability Prfiles Percent (%) Elevatin (feet) w kr-b kr-m b rv rs

29 LNAPL Mbility Calculatins The labratry measured LNAPL saturatin value was deemed t represent the maximum LNAPL saturatin pint at the sample lcatin (based n ROT and UV phtgraphy), thereby representing the greatest saturatin pint n the preceding saturatin prfile; This measured maximum saturatin was then used t determine LNAPL relative permeability, cnductivity, mbility and velcity.

30 LNAPL Mbility Calculatins LNAPL Mbility Calculatins (API, 2003) (API, 2003) w w w r K k K μ ρ μ ρ = w w w r K k K μ ρ μ ρ = = + + λ λ λ λ ), ( wr wr w wr wr t w r k 2 1/ 1/ 2 1/ ), ( = M M wr wr t M M wr wr w w r k

31 LNAPL Mbility Calculatins q = K i w v q = φ v eff φ eff K = φ φ = w v i v = M i w

32 LNAPL Mbility Calculatins Table 6.2 LNAPL Relative Permeability, Cnductivity, Mbility and Velcity Calculatins (1) LNAPL Area 9/10 Data Input Values Lcatin, Data Input and Calculatins RI-01 RI-04 RI-12 RI-15 RI-48 RI-49 RI-52 RI-55 RI-59 LNAPL aturatin ( ) Water aturatin ( w ) Ttal Fluid aturatin ( t ) Irreducible Water aturatin ( wr ) van Genuchten N (N) LNAPL Density (ρ ) - (g/cm 3 ) LNAPL Viscsity (μ ) - (cp) Ttal il Prsity (Φ) Assumed Average LNAPL aturatin ( avg ) Hydraulic Gradient Hydraulic Cnductivity Water (K w ) - (cm/s) 1.00E E E E E E E E E-04 Calculated Parameters Mdel Parameter 1 (λ) Mdel Parameter 2 (M) Maximum LNAPL Relative Permeability (k r ) 1.05E E E E E E E E E-03 Maximum LNAPL Cnductivity (K ) - (cm/s) 1.08E E E E E E E E E-08 Maximum LNAPL Mbility (M ) - (cm/s) 5.78E E E E E E E E E-07 Maximum LNAPL Velcity (V ) - (cm/s) 2.89E E E E E E E E E-09 Average LNAPL Relative Permeability (k r ) 2.63E E E E E E E E E-03 Average LNAPL Cnductivity (K ) - (cm/s) 2.69E E E E E E E E E-08 Average LNAPL Mbility (M ) - (cm/s) 2.89E E E E E E E E E-07 Average LNAPL Velcity (V ) - (cm/s) 1.44E E E E E E E E E-09 Ntes: (1) - LNAPL relative permeability calculatin fr sands based n Burdine Equatin 2.26 and Equatin 2.27, and fr silts based n Mualem Equatin 2.28 in American Petrleum Institute (API) Publicatin Number 4729, Mdels fr Design f Free-Prduct Recvery ystems fr Petrleum Hydrcarbn Liquids, August (2) - Highlighted data input values were based n labratry test results fr ite-specific sil and LNAPL samples. (3) - Hydraulic cnductivity water values based n labratry grain size analysis and listed hydraulic cnductivity values in Freeze and Cherry Grundwater, Table 2.2, p. 29. Prentice Hall. 604 p. (carse sand cm/s; medium sand cm/s; fine sand cm/s; silt cm/s)

33 LNAPL Mbility Calculatins Based n calculatin results, nly 1 f the 24 lcatins exhibited an LNAPL velcity in excess f 1 x 10-6 cm/s, which represents the de minimis mbility threshld fr LNAPL (ATM, 2005); Upn re-calculatin using assumed average LNAPL saturatins, nne f the 24 lcatins exhibited an LNAPL velcity in excess f 1 x 10-6 cm/s.

34 LNAPL Mbility Cnclusins Based n labratry measured LNAPL saturatins and residual saturatins, it appears that 4 lcatins within the interir prtins f the LNAPL areas exhibit a significant ptential fr inherent mbility; Based n LNAPL mbility calculatins, it appears that 1 interir lcatin exhibits an LNAPL velcity in excess f the de minimis mbility threshld fr LNAPL (ATM, 2005); Overall LNAPL areas appear t be stable.

35 LNAPL Recverability Operated a high vacuum multi-phase extractin (MPE) system in ne f the LNAPL areas fr 2 mnths (see Cushman et al., RemTech 2005, fr descriptin f system); Extractin area included area f maximum LNAPL mbility; Recvered apprximately 85,000 gallns f water but less than 40 gallns f LNAPL, despite an LNAPL in-well thickness f 6 feet.

36 LNAPL Recverability Ran LNAPL recverability simulatins using the API Interactive LNAPL Guide Versin 2.0 sftware; Assumptins: LNAPL type diesel; il types medium sand, silt, and clay; LNAPL area dimensins 200 feet by 200 feet; Apparent LNAPL thickness 8 feet (mdel assumes 8 feet LNAPL thickness acrss the entire 200 feet by 200 feet area); Recvery time 1 year; and Recvery system high vacuum extractin applying 18 Hg t 30 extractin wells.

37 LNAPL Recverability API Mdel simulatin results: il Type Estimated 1-year LNAPL Recvery (gallns) Medium and 295,000 ilt 4,100 Clay 130

38 LNAPL Recverability 10 ft Mnitring Well Thickness and a Diesel Fuel 18 Height Abve LNAPL/Water Interface (ft) andy ilt urce: U.. EPA Remediatin Technlgies Develpment Frum ilty and and LNAPL aturatin (%)

39 LNAPL Recverability API mdel simulatins demnstrate that significant in-well thickness (8 feet in this example), particularly in a fine textured sil (silt, clay), des nt necessarily mean that the LNAPL is recverable. Evaluatins suggest that inherent LNAPL mbility in a given area will nt necessarily translate int a high degree f recverability. LNAPL recverability is best tested with site- specific and technlgy-specific pilt studies.

40 Regulatry Feedback LNAPL Mbility Evaluatin Reprt yet t be submitted t U.. Envirnmental Prtectin Agency (U.. EPA).

41 Acknwledgements The authrs wish t thank General Mtrs Crpratin fr their cntributins t this paper and t the nging LNAPL evaluatin effrts.