NCD003446721_19960601_Celeanse Corporation - Shelby Fiber_FRBCERCLA RA_Evaluation of the Polymer Extraction Well System-OCR

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I Evaluation of the PEW {Polymer
I Extraction Well) System
Hoechst Celanese Corporation
I Shelby, North Carolina
I Submitted to
I State of Nonh Carolina
Department of Environmental Health
and Natural Resources
I Prepared/or
I Hoechst Celanese Corporation
Shelby, Nonh Carolina
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June 1996
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I Kubal-Furr & Associates
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Contents
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Introduction .................................................... 1
Background .................................................... 3
Evaluation of Fmdings ............................................. 6
Recommendations ............................................... 12
Tables
Table 1. Summary of Selected Water Quality Data ......................... 5
Figures
Figure 1. Site Plan Showing Location of PEW System ...................... 2
Figure 2. Monitor Well F-55 TOC Data ................................ 7
Figure 3. Hydrogeologic Cross Section Thro PEW System, July 25, 1989 ......... 8
Figure 4. Construction Details of Wells F-55 and PEW-2 .................... 10
Figure 5. Hydrogeologic Cross Section Thro PEW System, August 21, 1995 ....... 11
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Introduction
Hoechst Celanese Corporation (HCC) has been recovering ground water from a PEW
(polymer extraction well) system at its Shelby, North Carolina facility since June 1, 1994. The
PEW system was installed to recover Dowtherm and dissolved Dowtherm constituents from the
saprolite aquifer along the tank car unloading area behind the main manufacturing part of the plant
(Figure 1).
Semiannual reports documenting PEW activities have been prepared and submitted to the
State in accordance with a work plan and consent agreement entered into between HCC and the
DEHNR. Based on the data collected during the first two years of operation, it does not appear that
the magnitude nor the extent of the Dowtherm release near F-55 was as great as originally thought
As a result, HCC has requested that Kubal-Furr & Associates (KF&A) evaluate current conditions
and operation of the PEW system and to discuss the appropriateness of the on-going monitoring
and remediation. The following report describes operation of the PEW system and assesses the
system's effectiveness in achieving the original project objectives.
Kubal-FUJT & Associares/Page 1
Hoechst Celanese Corporation. Shelby. NC
Evaluation of Polymer Extraction Well (PEW) System
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• Monitor well
o Monitor well cluster
+ Inner Tler Extraction Well
♦ Outer Tler Extraction Well
c Domestic Supply Well
....
--I
Piezometer
Stream/Creek
l!lll HCC Building/Structure
♦ Abandoned Outer Tler Well
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--.;:_;_--------'"',
0
(
)!
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Scale In Feet
400
Kubal-Furr & Associates Figure L Site Plan
800
I " Abandoned Inner Tler Well A-A' Location of geologic cross-sections -Environmental Consultants-Hoechst Celanese Corporation ._ ____________________________________________ ,L ________________ .J. _______ s:h:e:l:b~y,~N=ort:,:h2c:a:ro:l:in:a:_ _____ _j
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Background
The presence of free product (Dowtherm) was originally reported in well F-55 during a
routine sampling event on August 9, 1991. It was speculated at the time that a spill of Dowtherm
from adjacent storage tanks was the cause of the problem. The source of the leak was later changed
to possible spillage from tank car unloading however, no definitive source was ever determined to
be the cause.
Although the 1991 event was the first reponed instance of free product in the monitor wells,
the presence of "strong chemical odors" (i.e., Dowtherm) has been reported to depths of 60-ft
below land surface on boring logs dating back to 1981 (G-50, G-88 and F-55). Based on this
information, it appears that incidental spillage of product during use or during tank car unloading
had occurred some time prior to 1981. The accumulation of free product in F-55, however,
suggests a more concentrated source such as a spill or line break, but the existence of such a source
has never been identified or confirmed.
After free product was detected, a special sampling event was conducted on September 12,
1991. Monitor wells F-55, G-50, G-88, H-59, H-79, and U-39 were sampled for semivolatile
organics (SVOCs), and 1,1 biphenyl; the latter parameter, along with biphenyl ether, being the
principal constituents in Dowtherm. The constituent 1,1-biphenyl was detected at F-55 and G-50 at
28,000 and 430 µg/L, respectively.
Several approaches were considered by HCC's consultant for recovering the residual
Febru.4."''I ,, 1 ctq,"3
Dowtherm, and a work plan was submitted to the NCDEM on Deee1111Jer 20; 1992. In the interim,
several additional sampling events were conducted and in January 1992, a pump was installed in
well F-55 that removed approximately one quart of Dowtherm between January and May. The
work plan submitted to NCDEM indicated that pumping at F-55 would stop after the proposed
PEW wells became operational, however, this has yet to occur and F-55 has pumped continuously
since January of 1992.
Sampling of wells F-55, G-50, G-88, H-59, H-79, J-28, J-59, U-38, B-34, and BB-18
occurred on August 11, 1992. This sampling event reported the presence of Dowtherm
constituents at B-34, F-55, and G-50. One additional sampling event at B-34 occurred on October
1, 1992 which confirmed the presence of Dowtherm constituents (biphenyl ether only) at this
Kubal-Furr & Associates/Page 3
Hoechst Celanese Corporation, Shelby, NC
Evaluation of Polymer Extraction Well (PEW) System
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location. A ~nmmary of data collected for the PEW project, including the results of a recent (April
15, 1996) sampling event are presented in Table 1.
The PEW wells were installed in August 1993. Estimated yields of between 2 and 6 gallons
per minute were proposed for the PEW wells, which began pumping on June 1, 1994. The time
lag between installation and start-up was caused by a delay in receiving state approval to modify
the NPDES permit Since start-up, the PEW wells have been sampled semiannually, and reports of
system performance have been submitted to the DEHNR.
Kubal-Furr & Associates/Page 4
Hoechst Celanese Corporatio11. Shelby, NC
Eva/Ulllio11 of Polymer Extractio11 Well (PEW) System
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Table 1. Summary of PEW Analyllcal Data
1.1-bfnhanvl Bfnt-ua e1tw Ett.u1ene GI-Bennne 1 "J..ftlchloroethent 2~HaxanoM Trk:hk>roethene
G-50
EEII■•,i■
G-88
9/12191 BCll. NA
8111192 BCll. BCll.
4115196 BCll. BCll.
H-511
9/12191 BCll. NA
8111192 BCll. BCll.
4/15196 BCll. BCll.
H-71
9/12191 BCll. NA
8111192 BCll. BCll.
4/15196 BCll. BCll.
.1-28
8111192 BCll. BCll.
.1-511
8111192 BCll. BCll.
~
9/12191 BCll. NA
8111192 BCll. BCll.
8-34
8111192 BCll. ■1€:1Jl'4 10,'1/92 BCll. ·<t:n..~,,,10=«--=.,ru_ 4115196 BCll. t-;,.,:t;:::/:f?-f Wff¾t
BB-18
8111192 BCll. BCll.
5-50
4/15,116 BCll. BCll.
PEW-1
619194 BCll. BCll.
12/14,94 BCll. BCll.
5l3M5 BCll. BCll.
11129,95 BCll. BCll.
PEW•2 ,21: ,,,-_,··<~,•ir tlllli•
11129'95 BOI. BOI.
PEW-3
12/14,94 BCll. BCll.
5/30/95 BCll. BCll.
11129,95 BOI. BOI.
PEW-4
619194 BCll. BCll.
12/14.94 BCll. BCll.
5l3M5 BCll. BCll.
11/29,95 BCll. BCll.
Notss: All measun,ments an, In pg,t. (ppb).
BQl.-86/ow OuantlJitJon UmN
NA-Not Ana/yzsd
Dams mJxss,mt Dal9 of Col/sci/on
NA
BCll.
NIA
NA
BCll.
NA
NA
BCll.
NA
NA
BCll.
NA
BOI.
BCll.
NA
BCll.
BCll.
NA
NA
BCll.
NA
BCll.
BCll.
BCll.
BCll.
BCll.
BCll.
BOI.
BCll.
BCll.
BOI.
BCll.
BCll.
BCll.
BOI.
NA
NIA
NA
BOI.
NA
BCll.
NIA
NA NA ea. BCll.
NA NA
NA NA
BaL. ·plti.ffilf:ti~iit
NA NA
NA NA
Bot. . .> . :;;,. ·ll½x"'*:-!"'~t~"'-#"'d~"'~•~I
NA NA
BCll. BOI.
BCII. BCII.
NA NA ea. BCll.
BCII. BCll.
NA NA
NA NA
BCII. BCII.
NA NA
ea. Bal
BCII. Bal
BCII. Bal
BCII. BOI.
·:::-:-: ·' <t=· Bal
BCII. BOI.
BOI. BOL
801. Bal
BCII. Bal
B01. BOI.
B01. Bal
BCII. Bal
BCII. BCll.
BCII. BOI.
NA
\'WWf~mt
NA
BCll.
NIA
NA
BCll.
NA
NA
Bal
NA
NA
BCII.
NA
B01.
BCll.
NA
Bal
BCll.
NA
NA
Bal
NA
Bal
Bal
BCll.
BCll.
BCll.
BCll.
B01.
Bal
Bal
BQI.
Bal
BCll.
Bal
B01.
NA
BCll.
NA
BCll.
NIA
NA
NA
U&~\t:
NA
B01.
BCll.
NA
Bal
Bal
NA
NA
Bal
NA
Bal
Bal
BQI.
BCll.
Bal
BQI.
Kubal-FWT & Associates/Page 5
Hoechst Celanese Corporation, Shelby, NC
Evalualion of Polymer Extraction Well (PEW) System
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Evaluation of Findings
Based on a review of project files, work plans, hydrogeologic cross sections, and the water
quality database, KF&A has identified several key findings related to the PEW extraction well
system and its operation:
1). To date, only one quart of Dowtherm has been recovered from F-55. The F-55 TOC
data, which "spikes" around the time free product was identified in this well (Figure 2)
has receded from a high of 1000 mg/L to less than 50 mg/L during the most recent
sampling event in April of 1996. Because Dowtherm constituents have been reported at
low concentrations in several areas of the plant, it appears that some incidental spills or
leaks occurred in the past. However, the data do not provide any indication that the
accumulation of free product at F-55 was other than a small spill, limited in areal extent.
2). The presence of Dowtherm constituents found during the sampling of F-55 are not
unexpected considering that free product was identified in this well. However, based on
the direction of ground-water movement in the saprolite aquifer in this part of the plant
prior to any pumping (see Figure 3), there was no component of flow from which to
infer movement in the direction of the G-cluster from F-55. The presence of Dowtherm
constituents at G-50 and G-88 therefore, would not be expected, except for the fact of
the notations referring to strong chemical odor found on the boring logs from 1981.
It should be noted that during drilling of monitor wells at the plant, no particular
precautions were taken to segregate any contaminated zones. It's very likely that near-
surface Dowtherm contamination was carried downhole at G-50, G-88 and F-55 as the
borings were advanced as opposed to having migrated to a depth of 60-ft as a result of a
Dowtherm spill.
3). Although there is a component of flow from F-55 toward well B-34 (Figure 3), the
presence of Dowtherm constituents there, but not in either well in the H-cluster, is
unusual and cannot be explained with currently available data. Judging from the low
concentrations found at B-34, it appears that the presence of Dowtherm constituents in
this area may be the result of a minor source area north of the H-cluster rather than
migration downgradient from the F-55 spill area.
Kubal-Furr&: Associates/Page 6
Hoechst Celanese Corporlllion, Shelby, NC
Eval"'1lion of Polymer Extraction Well (PEW) System
wa1sls (A\3J) 11•M. UOJJ3'1Jtrg .owl/OJ Jo uoµrm]rJ11.:;r :JN 'Af//al/S 'uoµr,,odJo;:; ••:JUTJI•:J /Sl/3>0H L a8rJJ/S"lf1PO<Sy ~ .Lm,J·TrJ</ffX Total Organic carbon (mg/L) 0 11/24/81 3/4/82 • 8/9/82
9/9/82 •
9/1 /83 '
8/17 /84 •
9/11 /85 •
9/13/85 •
g> 3/18/87 •
3 "D 2/8/88 CD° •
C D> -CII 6/20/88 •
8/16/88 •
10/25/88 ~
8/13/90 "
8/9/91 "
8/11 /92 I-
8/1 0/93 I-
8/25/95 I-
4/15/96 C '
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+ -I 0 0 -3
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r-----------------------------------------------------=:::::::;-
-
890.00
870.00
850.00
830.00
810.00
790.00
·110.00
750.00
r
!
L
f
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S-50
1----7
NM
810
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--I-
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Line of equal fluid potential (ft msl). Dashed
where inferred.
Potentiometric Surface
Inferred direction of ground-water movement
~· ~ .. ~ • J
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G-50
G-88 PEW-4
810.71
t! ;n'
j
811.68
Bedrock
Saprolite
Screened Interval of Well
PEW-3 F-55 PEW-2
~-,, -,.........,..,_ , ' , ., _,v,,,,,.,,, __
H-59 H-79 PEW-1
803.78
Kubal-Furr & Associates
-Environmental Consultants-
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890.00
870.cxi
850.00
830.00
810.00
790.00
? __
770.00
750.00
730.00
Figure 3. Hydrogeologic Cross-Section throuah
PEW System (Pre-Pumping Conditions) 0
July 25, 1989
Hoechst Celanese Corporation
Shelby, North Carolina
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4). One problem noted during construction of the PEW wells was identified at PEW-2. At
this location, the borehole collapsed twice and apparently was left open over a weekend
while a work-around was evaluated. The well construction problems at PEW-2 resulted
in an improperly constructed well which should probably have been plugged back
rather than completed.
Figure 4 shows the construction details of wells F-55 and PEW-2. The important
feature to note is the very long screen and extremely long sand pack at PEW-2. The
sand pack actually overlaps the F-55 screen and sand pack, and the construction of this
well (PEW-2) can easily cause contamination to move from upper portions of the
saprolite aquifer to deeper zones at the saprolite/bedrock contact
Rapid recirculation of any contamination vertically down the permeable annular space of
PEW-2 is virtually assured, especially in this pumping well which is "pulling"
contamination downhole to the well screen and pump (see Figure 5, showing pumping
water levels developed by the PEW system). It appears that the impacts due to
construction of this well have already been demonstrated because PEW-2 is the only
extraction well to have detected any Dowtherm constituents.
5). Wells PEW 1, 3, and 4 are pumping from deep, clean zones in the lower saprolite
aquifer and their use should be discontinued. If these wells are successful in removing
any Dowtherm constituents, they will only do so by pulling them down to the bottom of
the aquifer and introducing contamination into areas where it previously did not exist If
any well is to be pumped at this time, it should be F-55, which can more directly
remove any residual contamination migrating downward from a surface spill.
Kubal-Furr & Associates/Page 9
Hoechst Celanese Corporation, Shelby, NC
Evalllalion of Polymer Extraction Well (PEW) System
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850.00 F-55
Grout
830.00 O.CJto25.5'
Bentonite Seal ., 25.5' to Zl .a I
·::::
810.00
Sandpack
Zl.Gto55.G ·~
f:
' "'
Screen
790.00 500to550
770.00
750.00
730.00
710.00
Kubal-Furr & Associates
-Environmental Consultants-
PEW-2
, ..
'
Grout
0.GtDl7.D'
B,:mtonite Seal
17.0to3W
San~ack 320' 98.G
Screen
65f/to96.a'
850.00
830.00
810.00
790.00
770.00
750.00
730.00
710.00
Figure 4. Construction Details of
Wells F-55 and PEW-2
Hoechst Celanese Corporation
Shelby, North Carolina
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890.00
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830.00 r
[
I 810.00
l l
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790.00 ;
' I
I 770.00 l 801.82
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I 750.00
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I -Pocentiometric Surface
Inferred direction of ground-water movement
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805
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Bedrock
Saprolice
• • • •
G-50
G-88 PEW-4
807.16
Screened Interval of Well
PEW-3 F-55 PEW-2
100 200 400
H-59 H-79 PEW-I
INFERRED
CAPTURE ZONE
PEW SYSTEM
Kubal-Furr & Associates
-Environmental Consultants-
l 890.00
I l
! 870.00
l 850.00
830.00
810.00
790.00
? __ _
770.00
750.00
j
730.00
Figure 5. Hydrogeologic Cross-Section through
' PEW System (Pumping Conditions)
August 21, I 995
Hoechst Celanese Corporation
Shelby, North Carolina
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Recommendations
Based on the findings of the PEW system review, the following recommendations are
suggested as modifications to the current remediation system:
1). Well PEW-2 is improperly constructed, can introduce contamination to deeper,
previously clean portions of the saprolite aquifer, and should be properly abandoned
by overdrilling the well and grouting the entire borehole back to land surface.
2 ). The data suggest that the spill which resulted in an accumulation of free product in F-55
was fairly small and limited iri extent,. Continued operation of the system appears
unnecessary and may in fact be counterproductive if PEW-1, PEW-3 and PEW-4
successfully smear near-surface contamination across the saprolite down to the top of
the bedrock.
3 ). We would suggest allowing the entire system to be shut down for a period of from 3 to
6 months and then to sample the original wells (F-55, G-50, G-88, H-59, H-79, B-34)
and the PEW wells (1, 3 and 4) to determine the current distribution of Dowtherm
constituents in the upper saprolite aquifer. These data would be reported to the DEHNR
at which time a decision can be made as to the need for any further remediation efforts.
Kubal-Furr & AssociallS!Page 12
Hoechst Cdanese Corporation, Shelby, NC
EWJlualion of Polymer Extraction Well (PEW) System