NCD991278953_19970603_National Starch & Chemical Corp._FRBCERCLA RA_Response to EPA & DENR Comments on RD RA Field Investigations Summary & Conceptual Design Reports-OCR

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0.tlonal Starch and Chem/cal Company
10 Finderne Avenue
P. 0. Box 6500
Bridgewater, New Jersey 08807-0500
908-685-5000
Cable Address: NASPAOD,BRlDGEWATER/IEWJERSEY
Writer's Direct Dial Number:
Fax Number:
908-685-6991
908-707-3763
Mr. Jon Bornholm
Remedial Project Manager
United States Environmental Protection Agency
Region IV
100 Alabama Street, SW
Atlanta, Georgia 30303 -3104
June 3, 1997
R12c121v120
:JUN 26 1997
SUPERFUNO SECT/ON
Subject: Cedar Springs Road Plant Site, Salisbury, North Carolina
Superfund Project Operable Unit 3
Response to USEPA and NCDEHNR Comments on
RD/RA Field Investigations Summary Report and
RD/RA Conceptual Design Report
Dear Mr. Bornholm:
Attached please find seven copies ofNSCC"s response to USEPA and NCDEI-INR comments on
the RD/RA Field Investigations Summary Report and RD/RA Conceptual Design Report
for Operable Unit 3. This response will be bound in these two reports.
We sincerely thank you for your continued assistance and USEPA's guidance. Please do not
hesitate to call me at 908-685-6991 if there are any questions.
Very Truly Yours,
National Starch and Chemical Company <5,.~,~~
Corporate Director of Environmental Projects
CC: D. Cregar, NSCC A. Samson, NSCC R. Paradowski, NSCC
S. Velicheti, NSCC M. Ford, NSCC
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Responses to U.S. EPA Comments (05/12/97) on the
Remedial Design/Remedial Action Field Investigations Report
for the Third Operable Unit (OU3)
National Starch & Chemical Company
Cedar Springs Road Plant, North Carolina
A. Field Investigations Summary Report Contents
Comment No. 1
Page 45, Section 5.1, Second Paragraph, Seventh Sentence:
This sentence states that the pumps were placed IO feet above the bottom of the well except at
NS-54 where it was placed 30 feet above the bottom of the well. A short explanation needs to be
added to this paragraph stating why the alteration in well NS-54.
Response No. 1
At the Bedrock Well NS-54 the Driller had considerable difficulty during drilling and installing
the well. Initially the 6-1/8" bore hole for this well was completed down to 201 feet.below the
ground surface. After increasing the bore hole diameter to 9-7/8" with an Air Hammer Bit the
Driller encountered obstruction at 70 to 80 feet below the ground. This obstruction was removed
by using the Cable Tool Method and to prevent any further obstruction in the borehole, a 6"
galvanized pipe casing was installed down to 120 feet below ground surface (the Driller and the
Geologist established that the top of bedrock at this location is at 111 feet below the ground
surface). After installation of the casing the Driller encountered a second obstruction in this
well at 178 feet below the ground surface. This obstruction could not be removed in spite of
several attempts by the Driller and as a result the submersible pump could not be lowered below
this obstruction. To avoid damage to the pump in this well it was installed at 171 feet below the
ground surface ( 31 feet above the bottom of the bore hole). Since the total drawdown in this
well under pumping condition is only about 26.31 feet, installation of the pump 31 feet above
the bottom of the well will not affect designed extraction rate from this well.
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Comment No. 2
Page 56, Table 5-11:
Oversight, in the rest of the accompanying tables providing the drawdown observations for the
step tests the well tested itself was included in the table. In Table 5-11 well NS-45 was omitted
from the table.
Response No. 2
This was indeed an oversight. The observed drawdown in Well NS-45 during the Step-
Drawdown Test at the end of the 57 minutes test was 44 feet from the top of the casing.
Table 5-11 has been modified to include this data.
Comment No. 3
Page 93, Section 8.0, fifth sentence:
Typo, the beginning of this sentence starts, "Tables 6-1 and 6-1 ..... "
Response No. 3
This sentence should read as," Tables 6-1 and 6-2 show respectively the detected organic
compounds and the inorganic substances found in samples collected from monitoring and
extraction wells during the groundwater sampling event performed in January 1997."
Comment No. 4
Page 93, Section 8.1;
Based on the text presented in this section, it appears that the vertical extent of the contamination
was not defined in Area 2.
Response No. 4
It is correct that the vertical extent of groundwater contamination of the bedrock zone in Area 2
of the Plant could not be confirmed from the sampling and analysis of the Bedrock Wells
conducted during the Packer Tests.
However, during the drilling of the boreholes in Area 2, the Bedrock in this area was found to be
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.w~11 .r nf ~f~;,_g;;:t . . ··••trc:iiti i.i-s~4·.····
NS-24 604
NS-35 231. 0
NS-36 219.7
NS-45 0.25
NS-46 177.7
NS-47 183.3
Table 5-11
Drawdown Observations for Step Test NS-45
Monitoring Wells and Extraction Well
OU3 RD/RA Field Investigation
• Drawdown (ft.) ·After
57 min.
0
0
0
44
0
0
Note: The screened interval is measured from the ground surface.
Interval
55 to 75
6.5 to 11.5
25.8 to 40.8
12.7 to 52.7
50 to 200
11.7 to 41.7
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very competent with little or no fractures. The pumping rates and specific capacities of the two
boreholes NS-46 and NS-48 in the bedrock in Area 2 were found to be small at depths I 03 to
111 feet below the ground surface. Analysis of groundwater samples taken from the two bore
holes NS-46 and NS-48 during the Packer Tests indicated that the contamination in the
groundwater at depths ( over 144 feet in NS-46 and over 131 feet in NS-48) is very small. Thus,
from about 130 feet to the bottom of the two Bedrock Wells groundwater is found to be only
slightly contaminated. This detected low level contamination in the lower portion of the
boreholes in this area might be due to either of the two following reasons:
1. Groundwater at the bottom of the Bedrock Extraction Wells in Area 2 may have
been contaminated by migration of contaminated groundwater from above
through the open bore holes during the drilling and well installation operations.
This contaminated water may not have been completely removed during purging
of the borehole while conducting the Packer Tests. As a result low level
contamination remained in the bottom portion of the two boreholes .
If the bottom groundwater contamination in the Bedrock Wells in Area 2 is the
result of upper contaminated water migrating downwards, then this
contamination will be temporary and will disappear after these Extraction Wells
are operated for three to six months; or
2. Groundwater in Area2 of the Plant is contaminated beyond the 200 feet (from the
ground surface) depth of drilling and installation of the two Bedrock Extraction
Wells. In that case, the low level contamination found in the bottom
groundwater of the two Extraction Wells in Area 2 will persist even after
operation of these wells for three to six months. Then the contamination of the
bedrock in this area may be deeper than the 200 feet estimate made during the
conduct of the Remedial Investigations. In such a case, additional Drilling and
Packer Testing will be needed to determine the vertical extent of groundwater
contamination in Area 2.
At this time, based on review of the available data, National Starch and Chemical Company
(NSCC) believes that the low level contamination detected in the lower portion of the two bore
holes in the bedrock in Area 2 may have been caused by vertical migration of contaminated
groundwater from the upper Saprolite and Bedrock zones through the open boreholes. To verify
this, NSCC proposes to conduct the Pump and Treat operations at the two Bedrock Extraction
Wells in Area 2 for a period of six months.
At the end of six months of operation of the Bedrock Extraction Wells, NSCC will review the
groundwater contamination data from these two bedrock wells. If the groundwater
contamination persists in Area 2 bedrock wells, NSCC proposes to drill a new deeper bedrock
well in this area. The upper 150 feet of this bedrock well will be cased to prevent migration of
contaminated groundwater from above to the lower levels of the bedrock. Drilling of the new
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bedrock well beyond the 150 feet depth will be extended in 50 feet intervals up to 250 feet. Each
50 feet depth of the new bedrock well will be Packers Tested and samples of groundwater will be
collected to determine whether the groundwater within this interval is contaminated or not. If
the groundwater from this 150 to 200 feet interval is found to be contaminated, then the borehole
will be extended another 50 feet (from 200 feet to 250 feet). Packer Tests of this zone will then
be conducted and samples will be collected for analysis. Based on available data NSCC expects
the 200 to 250 feet zone of the bedrock to be uncontaminated.
Comment No. 5
Page 93, Section 8.2;
Based on the text presented in this section, it appears that the vertical extent of the
contamination was not defined in Lagoon 2 area.
Response No. 5
It is correct that the vertical extent of groundwater contamination of the bedrock zone in the
Lagoon 2 Arca could not be confirmed from the sampling and analysis of the three Bedrock
Wells NS-50, NS-52 and NS-54 during the Packer Tests.
However, during the drilling of the boreholes in the Lagoon 2 area, except for bore hole NS-54
the Bedrock in the NS-50 and NS-52 boreholes were found to be competent with some fractures
at different depths. The pumping rates and specific capacities of the two boreholes NS-50 and
NS-52 were found to be small at depths beyond 140 to 150 feet below the ground surface. But
the pumping rate and specific capacity of bore hole at NS-54 beyond depth 175 feet below the
ground surface were high.
Analysis of the groundwater samples taken from the three bore holes NS-50, NS-52 and NS-54
during the Packer Tests indicated that the contamination in the groundwater at depths beyond
170 feet was high and the groundwater is contaminated down to the bottom of all three Bedrock
Wells in the Lagoon 2 Area. This detected contamination might be due to either of the two
. following reasons:
l. Groundwater in the Lagoon 2 Area of the Plant is contaminated beyond the 200
feet depth (from the ground surface) of drilling and installation of these Extraction
Wells. Additional Drilling and Packer Testing will be needed to determine the
vertical extent of groundwater contamination in the Lagoon 2 Area; or
2. Groundwater at the bottom of the Bedrock Extraction Wells in the Lagoon 2 Area
may have been contaminated by vertical migration of contaminated groundwater
from above through the open bore holes during the drilling and well installation
operations. If the bottom groundwater contamination in the Bedrock Wells in the
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Lagoon 2 Area is the result of upper ~ontaminated water migrating downwards
through the open bore holes, then this contamination will disappear after these
Extraction Wells are operated for three to six months. However, if the
contamination of the bottom groundwater in these Extraction Wells persist after
operation of these Extraction Wells for three to six months, then additional
deeper Bedrock Wells will be needed to define the vertical extent of groundwater
contamination in the Lagoon 2 Area.
At this time National Starch and Chemical Company (NSCC) is not fully convinced that the
detected contamination at the bottom of the Extraction Wells in the Lagoon 2 area is due to
groundwater contamination extending beyond the 200 feet depth from the ground surface.
However, it is likely that groundwater contamination in the Lagoon 2 area extends beyond the
200 feet estimate developed by IT Corporation during the Remedial Investigations ofOU3.
To verify this, NSCC proposes to operate the Pump and Treat System for the Bedrock
Extraction Wells in the Lagoon 2 area for a period of six months. At the end of six months of
operation of the three Bedrock Extraction Wells, NSCC proposes to drill an additional deeper
bedrock well in the Lagoon 2 area to determine the vertical extent of groundwater contamination
in this area. This deeper borehole will be cased from the ground surface to 200 feet below the
ground to prevent movement of contaminated upper level groundwater to the lower depths.
After installation of the casing, the borehole will be extended.
Drilling of the new bedrock well beyond the 200 feet depth will be extended in 50 feet intervals
up to 300 feet. Each 50 feet depth of the new bedrock well will be Packer Tested and samples of
groundwater will be collected to determine whether the groundwater within this interval is
contaminated or not. If the groundwater from this 200 to 250 feet interval is found to be
contaminated, then the borehole will be extended another 50 feet (from 250 feet to 300 feet).
Packer Tests of this zone will then be conducted and samples will be collected for analysis.
Following review of the data from this depth, need for further drilling beyond the 300 feet depth
will be established after consultation with the USEPA and the NCDEHNR.
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Responses to U.S. EPA ,Comments (05/12/97) on the
Remedial Design/Remedial Action Conceptual Design Report
for the Third Operable Unit (OU3)
National Starch & Chemical Company
Cedar Springs Road Plant, North Carolina
Conceptual Design Report Contents
Comment No. 1
Page 16, Section 2.6, second paragraph, third sentence: Typo, "aand".
Response No. 1
Correction made. Thanks.
Comment No. 2
Tables 2-3 through 2.6 (where applicable): Define the data qualifiers "D" and "E". The
temperature of the water for each trail should be incorporated into each table.
Response No. 2
Qualifiers "D" and "E" have been defined and are as follows:
D
E
Dilution Performed
Exceeds Calibration Range
Temperature data for each trial have now been added to the data in Tables 2-3 through 2-6.
Comment No. 3
Tables 2-3 through 2-6: What parameter(s), if any, were changed/altered between the two
tests incorporated into each table. For example, in Table 2-3, what is the difference between
Trail B (8 scfm) and Trail C (8 scfm)? Or were these two trails duplicates?
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Response No. 3
In each of Tables 2-3 through 2-6 two sets of test results are presented for two separate Trial Runs. Same volume of contaminated groundwater and same air flow rate were used during both of these tests. Only differences between the two tests presented in each table are that two different samples with different quality characteristics were used in these two tests conducted on two different days and the temperature of the groundwater in the Aerator varied somewhat during the two tests due to variations of ambient conditions. The intent of the two tests using the same air flow rate but different quality characteristics was to demonstrate that the system is equally effective with groundwater of different quality characteristics.
Comment No. 4
Page 25, Section 3.1 This section lists the designed pumping rates (gpm) for each of the Extraction Wells, however, there are no calculations and rationale for deriving these pumping rates. This information needs to be incorporated into the document.
Response No. 4
The design pumping rates (gpm) presented in Section 3.1 are based on computerized modeling and analysis of the drawdown characteristics of the Saprolite and Bedrock Aquifers in Area 2 and in the Lagoon 2 area of the Plant. These drawdown characteristics were measured during the Step-Drawdown Tests in the ten newly installed Extraction Wells (5 Wells in Saprolite and 5 Wells in the Bedrock) and nine previously installed Monitoring Wells ( NS-I 3, NS-14, NS-24, NS-35, NS-36, NS-39, NS-40, NS-41 and NS-42).
Data collected during the Step-Drawdown Tests were used together with computer simulation to determine the cumulative drawdowns and groundwater surface contours in Area 2 and in the Lagoon 2 area at various rates of pumping from the ten Extraction Wells. Table 3-2 presents the drawdown measured during the Step-Drawdown Tests and calculated cumulative drawdowns at all Extraction Wells under design pumping rates.
Computer analysis was then used to calculate the areal extent of the cumulative drawdown (Area of Influence) due to pumping from the Extraction Wells at various locations. The Design Pumping Rates given in Table 3-1, are the pumping rates at which sufficient drawdowns are created in Area 2 and in the Lagoon 2 area so that the Area of Intl uence extends over the entire Contaminant Plume in both locations. This allows efficient extraction of the Contaminant Plume without inducing excessive migration of uncontaminated groundwater from outside the Contaminant Plume into the Contaminant Plume. Figure 3-2 illustrates the Area of Influence in Area 2 of the Plant while Figure 3-3 illustrates the Area of Influence in the Lagoon 2 area under design pumping rates and conditions.
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Table 2-4
Results of Pilot Test Trials D and E
Salisbury Plant Groundwater Remediation System -Operable Unit 3
1 n,n1n,rn1,:;a
Trial (Flowrate/femp.) Trial D !12 scfm//l 3.4°C1
Sample ID D-1 D-2 0-3
Sample Interval (hr.) 0 3 6
Parameter (ug/1)
Methylene Chloride 2000 JB 40 JB 2
Acetone 2500 u 20 JB 9
I ,2-dichloroethane 36000 I I 00 78
Total Concentration(ug/1) 40500 1160 89
Percent Removal 97.14 99.78
Notes:
2000 J = Reported value is an estimate
2000 B = The paramter was also detected in the method blank
10000 U = The value is less than the detection limit.
D = Dilution performed
E = Exceeds calibration range
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JB
JB
Trial E !12 scfm/16.4°C)
0-4 E-1 E-2 E-3
9 0 3 6
2 JB l000 JB 300 J 30 J
D
6 JB l000 .TB 200 JB 40 JB
D
9 J 90000 ED 8800 790
17 92000 9300 860
99.96 89.89 99.07
22
E-4
9
3 J
8 JI3
91
102
99.89
liiiiiil liiiiiil == == == == 1111,1 == 1111,1 1111,1 l!!!!I l!!!!!!I l!!!!I !!!!!!!!!I I!!!!!!!!! -l!!!!!!!i l!!!!!!!i!I -
Table 2-5
Results of Pilot Test Trials F and G
Salisbury Plant Groundwater Remediation System -Operable Unit 3
I J/1 nl 14.{)1t::O
Trial (Flowrate/Temp.) Trial F (16 scfm/16.8°C)
Sample ID F-1 F-2 F-3
Sample Interval (hr.) 0 3 6
Parameter (ug/1)
Methylene Chloride 1400 J u
Acetone u 48 DJ 17
B
1,2-dichloroethane 67000 2000 30
Total Concentration(ug/1) 68400 2048 47
Percent Removal 97.01 99.93
Notes:
2000 J = Reported value is an estimate
2000 B = The paramter was also detected in the method blank
I 0000 U = The value is less than the detection limit.
D = Dilution performed
E_ = Exceeds calibration range
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Trial G (I 6 scfm/18.0°C)
F-4 G-1 G-2 G-3
9 0 3 6
u 3 J 3100 J u u
B 27 B 2800 JB 63 DJ IO JB
B
2 120000 3400 51
32 125900 3463 61
99.95 97.25 99.95
23
G-4
9
3 J
10 JB
3 J
16
99.99
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Table 2-6
Results of Pilot Test Trials Hand I
Salisbury Plant Groundwater Remediation System -Operable Unit 3
I I 11 ~ •t\01.hO
Trial (Flowrate/Temp.) Trial H (20 scfm/16.6°C)
Sample ID H-1 H-2 H-3
Sample Interval (hr.) 0 3 6
Parameter ( ug/1)
Methylene Chloride u u
Acetone 970 JB u 84 DB 12
1,2-dichloroethane 61000 510 D 6 ..
Total Concentration(ug/1) 61000 594 18
Percent Removal 99.03 99.97
Notes:
2000 J = Reported value is an estimate
2000 B = The paramter was also detected in the method blank
10000 U = The value is less than the detection limit.
D = Dilution performed
E = Exceeds calibration range
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B
J
Trial I (20 scfm/14.3°C)
H-4 1-1 1-2 1-3
9 0 3 6
u u u u
13 B 1300 JB 83 B 76 B
u 140000 1400 E 76
13 141300 1483 152
99.98 98.95 99.89
24
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99.95
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TABLE 3-2
SALISBURY PLANT GROUNDWATER REMEDIATION SYSTEM· OPERABLE UNIT 3
EXTRACTION WELL DRAWDOWN CALCULATIONS
Drawdowns at Ste;, Test Pumping,_.R_.,a.._.t,ces,,_ ________ ~====-=--------------~
Pumping Pt=J;>ing DRAWDOWNS
Well : RaTE. g,"pm"'--'-'N-"S_-4c:5_..cN.:.S=.·.c.46=--''-"Nc:Sc..-4cc.7...;.l ..cN.:.S=.·..c48,,_...;.Nc:Sc..·4c:9:_;.I _N:.:S,c·.=5.::.0_..cN::.,Sc..·5=-1:....c-'-'N-=S•.=5:::.2--.--'N"'S'-'·5::.:3:.:..c_.:.:N,cS·.=5.:.4...:
I I I
NS-53 .110 2.141 0.291 0.61 1.•./¥t26,74' 17.131 fl NS-54 30 1.47! 1.6, 0.311 0.5, 11.91 ?$1\1:48,22 II Total :99 53.13 136.96 59.27 106.12 42.49 167.46
i
35.54 117.51 12.36 96.37
I
Static Waler Deptr
Pump lnlake Dept:'",
Max. Allowed Dra-wdown
8.37
54.45
46.08
15.15 23.84
188 40.55
172.85 16.71
16.43
187
170.57
8.72
107.12
98.4
8.03
186.12
178.09
6.39
107.22
100.83
5.89
186.12
180.23
9.06
107.22
98.16
8.14
174.12
165.98
I Drawdowns at Design PumJ)ing-'R_.,a,.,te,cs,,_ _________ --=====.--------------~
Pumping
1
, Ptr.iping DRAWDOWNS
Well Rat:. gpm NS-45 NS-46 NS-47 NS-48 ! NS-49 NS-50 NS-51 NS-52 NS-53 NS-54
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NS-45
NS-46
NS-47
NS-48
NS-49
NS-50
NS-51
NS-52
NS-53
NS-54
; .8
5
2
·,4
;5
5
;o
5
20
5
1.81 :xc,,10.42 0.15· 0.31 · 0.151 o.08i
0.22 0.22 ,,,20.64: 2.72, o 02 i o I
0.34' 0.34 1.41 ,~-f.• 17:-18 I I
o.89, o.94 o.o7; 0.18 ~'1fL12,13 6.59
0.14 1 o.17 o.04: 0.06 1 1.43 f·•n9,32
Total 83.8 40 151.68 12.36 123.26 17.96 18.62 22.52 21.18 14.27 26.31
m Static Water Levels & Well Elevations
Well No. NS-45 NS-46 NS-47 ! NS-48 ' NS-49 NS-50 NS-51 NS-52 NS-53 ! NS-54 I
m
i I I ,Top of Casing Elevation, f 754.85 768.99 I 769.621 770.22! 766.98 766.08 764.98' 764.67: 770.131 770.28 i Initial Depth to Water, ft 8.37 15.151 23.841 16.43 I 8.72; 8.03 6.39• 5.89' 9.061 8.14 I Static Water Level. ft 746.48 753.84 i 745.78 ! 753.79 i 758.26 758.05 758.59' 758.78 i 761.07 I 762.14 I
m Water Levels at Design PUmf)ing,..'.R_.,a.._.tcies:a-, ... ~=~--.--cc.-c~c-c==--.-~~~~=~-==~~=~~=~~
Well No. NS-45 NS-46 NS-47 I NS-48 NS-49 ' NS-50 · NS-51 NS-52 NS-53 I NS-54 I
m ,Water Level Elev .. ft
I
D
D
D OU3DDN.WK4
706.48 602. 16: I I I
733.421 630.53 740.3' 739.43 736 07; 737.6, 746.8 I 735.83 I
Page 1 06/03/9708'.38 AM
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DRAWDOWN
CONTOURS
EXTENT OF
CONTAMINATION
--
()
N. C. GRID NORTH (NAO BJ)
[NJ,tlonal Starch and Chem/col Company
SALISBURY, NC PLANT
V .x
X
X
AREA 2 EXTRACTION WELLS
AREA OF -INFLUENCE
JUNE 1997 FIGURE 3-2
7
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0 •
N. C. GRID NORTH (NAO BJ)
*
DRAWDOWN
CONTOURS
EXTENT OF
CONTAMINATION
\
cP )\
¥-0
/
*
V .x
X
X
X
X
J
~~G~ \
\'--' \ /\ / * /
r I-
0 50 100 150 JOO
FEET
{Nj,tlonal Slorch and Chem/co/ Company LAGOON AREA EXTRACTION WELLS
AREA OF INFLUENCE.
SALISBURY, NC PLANT JUNE 1997 FIGURE 3-3
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Comment No. 5
Page 25, Section 3. I, second paragraph, first sentence: This sentence states "120,000 gallons of
contaminated groundwater" however it does not give a time frame (i.e., gallons per hour, gallons
per day, etc.).
Response No. 5
This sentence is now corrected to read " A total of 120,000 gallons of contaminated groundwater
will be pumped each day from these ten newly installed Saprolite and bedrock Extraction Wells
installed for OU3.".
Comment No. 6
Page 26, Table 3-1: This table should also account for other parameters (general water
chemistry) such as pH, hardness, etc. that will need to be measured and controlled.
Response No. 6
Table 3-1 lists the critical VOC, SVOC and inorganic metal contaminants and their expected
concentrations in the Influent to the Air Stripping System and expected concentrations of these
contaminants in the Effluent from the Air Stripping System. Besides the contaminants listed in
Table 3-1, NSCC will measure and record other general chemistry parameters such as pH,
Temperature, COD, TSS, TDS, etc. in the Effluent from the Air Stripping Treatment System.
However, these are not critical parameters for air stripping. Because of this they are not listed in
Table 3-1.
Since the Effluent from the Air Stripping System will be treated further together with other
wastewater and contaminated groundwater in the Salisbury Plant's existing Combined
Pretreatment System it is not necessary to measure the suggested parameters for the Diffused Air
Stripping System. These parameters are now measured in the Combined Pretreatment System
for both the influent and effluent streams. However, if USEP A requires these measurements
NSCC will measure and report these parameters together with the VOC, SVOC and metals.
C:\rROJECTS\SALSBRY\OU3RES4.AA 8
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Comment No. 7
Page 27, Section 3.2, first sentence: Typo, this sentence contains two typos.
Response No. 7
Typos noted and corrected. Thanks.
Comment No. 8
Page 27, Section 3.3, fourth paragraph: Is there a point in time when NSCC anticipates being
able to by-pass the thermal oxidizer and discharge the exhaust air from the Diffused Air Stripper
Tanks straight into the atmosphere? If so, this situation needs to be discussed in this section.
This discussion should include the pertinent parameters that will lead NSCC to propose by
passing the thermal oxidizer.
Response No. 8
At this time NSCC does not anticipate bypassing the Thermal Oxidizer because of the presence
of Acrylonitrile in the contaminated groundwater from the Trench Area. In order to meet
NSCC's Air Permit Discharge requirements it will be necessary to thermally oxidize the
Acrylonitrile and other VOC's and SVOC's that might be present in the exhaust air from the
three Diffused Air Stripper Tanks.
Comment No. 9
Page 27, Section 3.3, fifth paragraph: Will the treated groundwater from OU #3 and the Trench
Arca be combined prior to being pumped to Lagoon #I?
Response No. 9
The Diffused Aeration Treatment System proposed in the Conceptual Design Report uses
separate Reactors for treating these two contaminated groundwater streams because of the
significant difference between the quality characteristics of the two streams. After treatment the
air stripped effluent from each Reactor will be pumped separately to Lagoon No. I. The two
separate streams will then combine and mix in Lagoon No. I with other wastewater and
contaminated groundwater from the Plume Periphery Extraction Wells.
C:\PROJECTS\SALSBRY\OUJRES4.AA 9
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Comment No. IQ
Figures 3-1 A and 3-1 B: The estimated flow rates should be incorporated into these figures.
Response No. I 0
Estimated flow rates will be included in the two Process Flow Diagrams (Figures 3-1 A
and 3-lB).
C:\PROJECTS\SALSBRY\OU3RES4.AA 10
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I L-
---------------------------------------------,7
' ~
NS-47
2"""
NS-40 . """
NS-45
1.8 GPM
AREA 2
SURGE TANK
2,000 GAL
I
CONTAINMENT
FROM TRENCH ARtA WELLS
~ g
NS-48
14 CPU
' ~
NS-49 ,. """
-
'
I:: --NS-50 . """'
EXISTING
PUMPS
' ~
NS-51 10 GPV
[XISTlNC TRENCH WA TEA SUMP
' ' ' ~
NS-5.J
20"""' I= ....
~ ~ ~ ----NS-52 NS-S4 . """ . """
25,000 CPO
R(V.
ABO ii.2. xt<Li, Sc.b., P.E.
IIOtTH CAIIICUuo fl' L. NO.
~
"'""""""
.
TRENCH WA T!R
EQUALIZATION TANK
(EXISTING Sl.UOCE TANK)
11,JOO CAL
I
--
-
003 RAW WATER
ECUAUZATION TANK
(EXISTING HYORO. YSIS TANK)
19,900 GAL
~
TRENCH WA TEA
TRANSFER PUwPS
EXISTING CONTAINMENT
RAW WATER
TRANsrtR PUMPS
EXISTING CONTAINMENT
DATE Clf-»IP.
$CAL[: lilOJrl[
{Ngttonal Starch and Chemical Company
SALISBURY PLANT OPERABLE UNIT 3
GROUNDWATER REMEDIATION SYSTEM
TO AERATION
TANK NO. ◄
25,000 CPO
120.960 CPO
TO AERATION
TANKS 1, 2, 3
PROCESS FLOW DIAGRAM
SHEET 1
JUNE 1997 I FIGURE 3-1A
_J
rr=-----------~---
1
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FROM TRENCH WATER
ECUAUZA TION TANK
25,000 GPO
120,960 GPO
FROM OUl
EOUAUZATION TANK
D--"-'<--0
C &
C N " 0 •
-I
D--"-'<--0 • OV9 MOV, T MOVll MOV21 MOV10 MOV2 T MOV,4 MOV22
--
AERATION TANK
NO. 1
.. . . . . .. ., . . .
AERA TICIN BLOWERS
"' / --~--------~_______,,/
~ EXISTING LACOON NO. 1 .
MOV,7
I-<~>-
I
.L
' D
, ...... ·-I
TR[A TtD WATER
TRAN5r[R PUMPS
~
-
AERATION TANK
NO. 2
.. , • • .. , • • .. ., .. i
.L .L
' l .
~
h,) ~
-
MOV,B
. ~>-l]
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REORCULATlON
PUMPS
.L
(
,.-'
~
C &
C N " ~
-I
D--"-'<--0 MOV11 MOVJ T MOV15
-
AERATION TANK
NO. 3
.. ., .. ., . " ..
UP TO 350 CPM
REOROJLA TION
""
MOV2l
MOV,9
~>-k[l
• I
NA l\JRAI. CAS
g
§
~
MOV,2 MOV4 T MOV16
D--"-'<--0 '<--0
--
AERATION TANK
NO. 4
. . . . . .
TO ATMOSPHERE
EXHAUST STAO<
HEAT
EXCHANGER
THERMAL Q)(IOIZ£R
I ACV. DESCRIPTION DATE ._"' ~ =~ L..,..,onal Storch and Chemical Company
'<--0 MOV24
. . .
M9V20
" . ~;s:7
•""'-
I
(:----1---~
PROCESS FLOW DIAGRAM
SHEET 2 -~ SALISBURY PLANT OPERABLE UNIT 3
~-------------------------------------J_m_0_..::_~_-,_::-_.·_.~~~~·~~--··_'·....L-J_ ______ ..-J. __ .L__""" __ '-_ __J __ G_R_O_u_N_D_w_A_T_E_R __ R_E_M_E_D_IA_T_I_O_N_S_Y_S_T_E_M_..L._ ___ J_uN_E_19_9_7 ___ .L_ __ FI_G_U_R_E_3_-_,_B_==1._J
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Responses to NCDEHNR Comments (05/09/97) on the
Remedial Design/Remedial Action Field Investigations Summary Report
for the Third Operable Unit (OU3)
Comment No. I
Figures 2-2, 2-3
Response No. 1
Figures 2-2, 2-3
Comment No. 2
Sect. 2.4
Response No. 2
Section 2.4
A:\OU3RES4.AA
National Starch & Chemical Company
Cedar Springs Road Plant, North Carolina
These figures should be amended to include a legend to identify the scale
of the map, symbols, location of plant, contour interval, and reference
datum.
These figures already contain a scale (l" =500') at the bottom of the
figures. Additional text and notations will be added to make the scale
clearer.
The first paragraph of this section indicates that the "Summary of site
Characteristics" portion of the report does not include the data collected as
part of the OU3 RD/RA Field Investigations. It is recommended that
National Starch & Chemical Company (NSCC) amend the summary of
site characteristics to include the data collected as part of the RD/RA Field
Investigations.
Section 2 of the RD/RA Field Investigations Report presents background
information and data collected during the Remedial Investigations. The
intent of this section is to inform the reader of the background of the site
and results of past investigations. The data collected during the RD/RA
Field Investigations should not be presented in this section.
NSCC agrees with NCDEHNR that the data collected from past Field
Investigations should be combined with data collected during the RD/RA
Field Investigations to evaluate and determine current site
characteristics. Table 6-4 has been added in the RD/RA Field
Investigations Summary Report to summarize the current site
characteristics for Groundwater together with site characteristics
determined during the OU3 Remedial Investigations.
11
~-----------------
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'J-':---, V
'v ,)
"'
' <>D
/2
N
+
◊ '
500 0 500
I -250
Scale 1 inch ~ 500 ft.
TRENCH
AREA
750 _.., I.T.
LAG I NO
+
+
&
+
(
~
,,
~ =+-O.~
1/
SITE MAP
' I
{ij..JlolXJI Sfort:h and Chemical Company
CEDAR SPRINGS, NC PLANT
'---------------------------------------------'---"-••_•·_._"'°___,_· _____________ __,_ __ M_AR_CH_1_99_1 _ __J __ r...:;g'-ur_e_2_-2_~
I
rr=-----~---------
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+
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0o ''."'-.
) 'v ,
,...,
AIRPORT
ROAD
500 0 500 ---------250 750
+ +
1/
{ilj,tlonaf Slarch and Chem/co/ Company WATERSHED MAP
I Scale 1 inch = 500 ft. -~ CEDAR SPRINGS, NC PLANT
c___~=------------------------------------------.L""'_••_·._,oo_·L_ ____________ ._J_ __ M_AR_CH_19_97 __ .J._ __ Fi.e,:.gu:....re:....2::_-...:.3_~
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Table 6-4
Range and Frequency of Detection of Organic Contaminants and Inorganic Constituents
Phase I and II OU3 RI and Field Investigation of OU3 RD/RA
Compound
Volatile Organic Compounds
Acetone
Bromodichloromethane
2-Butanone
Carbon Disulfide
Chloroethane
Chloroform
Dibromochloromethane
1,2-Dichloroethane
1, 1-Dichloroethene
1,2-Dichloroethene
1,2-Dichloropropane
Ethylbenzene ·
Methylene Chloride
Tetrachloroethene
Toluene
1, 1,2-Trichloroethane
Trichloroethene
Total Xylenes
Vinyl Chloride
Groundwater from RI
9-4,200 (15)
1
4-8 (3)
3-35 (6)
7-8,900 (2)
1-660,000 (30)
1-14 (3)
1-200(4)
5
9-36 (2)
1-160 (5)
107 (4)
1-120 (3)
1-5 (10)
2-90 (4)
1-120 (8)
Groundwater from RD/RA
4-2000 J (9)
130-260,000 (I 0)
2-3000 J (8)
Concentrations for water samples are reported in micrgrams per liter (ug/1) or in parts per billion
(ppb.)
Number appearing in parenthesis is the frequency of detection. .
The reported values for Groundwater RD/RA are only from the ten new extraction wells.
C:' PROJ ECTS\SLSBR Y\OU3\0U3CNDES. S V 8
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Table 6-4 (Continued)
Range and Frequency of Detection of Organic Contaminants and Inorganic Constituents
Phase I and II OU3 RI and Field Investigation of OU3 RD/RA
Compound Groundwater from RI Groundwater from RD/RA
Semi-Volatile Organic Compounds
Bis(2-chloroethyl) ether
Bis(2-ethylhexyl)phthalate
Di-n-butyl Phthalate
2-Methyl Phenol
N-Nitrosodiphenyllarnine
Pesticide
Delta-1-lexachlorocyclohexane
13-32 (2)
8
2-17 (3)
0.16
3-I 6 (7)
2 J (I)
2 J (I)
NA
Concentrations for water samples are reported in micrgrams per liter (ug/1) or in parts per billion
(ppb.)
Number appearing in parenthesis is the frequency of detection.
The reported values for Groundwater RD/RA are only from the ten new extraction wells.
\
C:\PROJ ECTS\SLS 13 R Y\OU 31QU3CNDES. S V 9
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Comment No. 3
Sect. 2.4.1
Response No. 3
Section 2 .4 .1
Comment No. 4
Table 2-1
Response No. 4
Table 2-1
A:\OU3RES4.AA
This section, titled "Site Soil Characteristics", lists the contaminants and
their concentrations in the soil. This section should also contain a
description of the type of soil (from ground surface to water table)
including properties such as chemistry, permeability, classification, grain
size, etc.
Section 2 of the RD/RA Field Investigations Report presents background
information and data collected during the OU3 Remedial Investigations.
The intent of this section is to inform the reader of the background of the
site and results of past investigations. The requested data were
presented in the two OU3 Remedial Investigations Reports.
The purpose of the RD/RA Field Investigations is to collect data
necessary to conduct design of the facilities for Groundwater
Remediation at OU3. No soils data such as background chemistry,
classification, grain size, etc. were collected during the RD/RA Field
Investigations because it was not necessary for design.
The term "frequency of detection" should be more clearly defined.
The term "frequency of detection" in Table 2-1 is meant to indicate the
number of times that particular VOC, or SVOC, or Pesticide, or
Inorganic Constituent was detected during the Remedial Investigations
conducted for O U3.
12
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Comment No. 5
Table 2-l
Response No, s
Table 2-1
Comment No. 6
Sect. 2.4.2
Response No,6
Section 2.4.2
A:\OU3RES4.AA
It is recommended that the inorganic analytical results be grouped to
distinguish up-gradient ( or background) concentrations from down-
gradient concentrations. This may help NSCC examine the inorganic
constituents that are naturally occurring.
Table 2-1 of the RD/RA Field Investigations Report presents background
information and data collected during the OU3 Remedial Investigations.
The intent of this section is to inform the reader of the background of the
site and results of past investigations. Evaluation of this data in terms
of up-gradient and down-gradient wells were conducted during the
conduct of the Feasibility Study. Further analysis of the data in terms
of up-gradient and down-gradient wells are unnecessary and will not be
done.
This section titled "Site Groundwater Characteristics" provides
information on the number and types of sampling points and the name and
concentration of contaminants ( excluding the information generated
during this investigation). It is recommended that the section be amended
to include (1) the information generated during the RD/RA Field
Investigations for OU3, as noted above, and (2) a description of the up-
• gradient (or background) groundwater quality conditions.
Section 2 of the RD/RA Field Investigations Report presents background
information and data collected during the OU3 Remedial Investigations.
The intent of this section is to inform the reader of the background of the
site and results of past investigations. The data collected during the
RD/RA Field Investigations should not be presented in this section.
NSCC agrees with NCDEHNR that the data collected from past Field
Investigations should be combined with data collected during the RD/RA
Field Investigations to evaluate and determine current site
characteristics. Groundwater data from past Remedial Investigations at
OU3 are now summarized with groundwater data from the RD/RA Field
Investigations in Table 6-4 of Sections 6 of the RD/RA Field
Investigations Summary Report.
13
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Comment No. 7
Sect. 2.4.4
Response No. 7
Section 2.4.4
A:\OU3RES4.AA
This section titled "Hydrogeological Setting", provides a brief description
of some of the aquifer characteristics. As noted above, it is recommended
that NSCC include the information developed during this investigation. It
is recommended that this section also include:
I.
2.
3.
4.
5.
Potentiometric maps for the different zones of the aquifer, and
cross-sectional flownets of the site;
An analysis and discussion of fracture trends and other preferential
pathways for groundwater flow;
A description of discharge and recharge zones at the site;
Descriptions of different aquifer zones (e.g., shallow, saprolite, &
deep);
An interpretation of contaminant flow in the aquifer.
Section 2 of the RD/RA Field Investigations Report presents background
information and data collected during the OU3 Remedial Investigations.
The intent of this section is to inform the reader of the background of the
site and results of past investigations. The data collected during the
RD/RA Field Investigations should not be presented in this section.
NSCC agrees with NCDEHNR that the hydrogeological data collected
from past Field Investigations should be combined with hydrogeological
data collected during the RD/RA Field Investigations to evaluate and
determine current site characteristics. Section 5 of the RD/RA Field
Investigations Summary Report has been modified to include the updated
evaluation of site hydrogeological data. NCDEHNR's recommended
item 1 for providing the Potentiometric Maps for the Saprolite and
Bedrock zones and item 5 for providing an interpretation of contaminant
flow are presented in section 5. Table 5-23 presents the groundwater
elevations for the saprolite and bedrock wells collected during the
RD/RA Field Investigations and Figures 5-1 and 5-2 show the
potentiometric surface elevations for the saprolite and the bedrock
aquifers.
NCDEHNR's recommendation to include items 2, 3 and 4 is
unnecessary, does not contribute any information to the Remedial Design
and will require substantial additional effort including additional field
work. These recommended items are not be included.
14
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Well I.D.
Saprolite Wells
NS-03
NS-12
NS-13
NS-14
NS-33
NS-35
NS-37
NS-39
NS-42
NS-43
NS-45
NS-47
NS-49
NS-51
NS-53
Bedrock Wells
NS-24
NS-34
NS-36
NS-38
NS-40
NS-41
NS-44
NS-46
NS-48
NS-50
NS-52
NS-54
Table 5-23
Groundwater Elevations for Saprolite and Bedrock Wells
RD/RA Program
Cedar Srpings Road Plant
Depth to Elev. of Elev. of
Water (ft.) TOC (ft.) Groundwater (ft.)
12.2 774.28 762.08
12.8 777.36 764.56
5.8 762.69 756.89
5.3 765.36 760.06
10.25 776.36 766.11
4 746.11 742.11
30.95 746.11 715.16
9.2 769.91 760.71
7.35 766.16 758.81
IO.OS 759.38 749.33
8.25 754.85 746.6
23.8 769.62 745.82
8.3 766.98 758.68
6.7 764.98 758.28
8.55 770.13 761.58
21 758.32 737.32
11.55 776.27 764. 72
3.85 745.59 741.74
30.35 745.61 715.26
8.55 769.34 760.79
7.2 766.03 758.83
9.65 759.3 749.65
16. 15 768.99 752.84
15.95 770.22 754.27
7.3 766.08 758.78
5.85 764.67 758.82
8.4 770.28 761.88
Notes: Water level readings recorded on February 6, 1997.
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tp
0 C -z_
0
1 --<
L
I NOTE: ELEVATIONS 8ASEO ON N.G.V.0. Of 1929 MOH.
I •10 JAS 1966 790• -El..EVATION: 789.4~'
Vl£ll SlRVEY SY SHULENEIJRGEA SURVEYING COIIPANY
516 N. MAIN ST., SAUS8URY, N.C. PHONE: (704) 6J7-N2J
LEGEND
IO NS-39
(760.71)
I~
I
Saprolite .,.. Locotion a:
Gr11Undwot11r Oevotion (II. MSl.)
Grounctwoter Counlor (ft. USL)
730
740
PROPERTY LINE (APPROX)
,., ,.,
\
I
)
■ ■ • ■ • f ■ • • • •
0 U)O 200 <00 000 800
Figure 5-1
Groundwater Elevation Contours
Saprolite Wells
NATIONAL STARCH & CHEMICAL CO. L__ ________ ..1_ _______________________________________ ----'-------------------~
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NS-oii
o:J 0 C -z t:J
J;>
;Q -<
L
NOTE: ELEVA TJONS BASED ON N.G. V.0. ~ 1'1:nil YON.
"10 JA5 1966 790" -[l£VATION: 7811.452'
WEll ~y 8Y SHULENBURCER SURVEYING COMPANY
516 N. ~ ST .. SAUSEIURY. N.C. PHOfril(: (704) 6J7-962J
l1--~L=-EG=E=N-"D'----'-------;
0 NS-39 Beo,od,; w.n Locotlon 6:
(760.71) Potenllom■trlc Surfoc■ (It. 1151..) I ~ Potenliom11trlc Counlor (ll. IISL) -~
720 730
L
~ -------· .. // ;,-/
/,/ /✓1/ /, 1/
//
;'. /
I I.
\I
0 \ NS-45
PROPERTY LINE (APPROX)
740
NS-r (764.72)
NS-JJ
.,., .,.,
\
I
)
;i
~ ~
~ ! z
Q s
u
z
..... .,... ..... -. ■■■■■--0 100 200 600 800
Figure 5-2
Potentiometric Surface Contours
Bedrock Wells
NATIONAL STARCH & CHEMICAL CO. iL__ ___ ----1. _____________________ ..___ ______ ___,
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Comment No. 8
Figs. 2-7, 2-8 The cross-section and cross-section location map are missing.
Response No. 8
Figs. 2-7, 2-8 These two figures are attached to this response.
Comment No. 9
Sect 4 3
Response No. 9
Section 4.3
A:\OU3RES4.AA
This section describes each of the packer tests, however, it does not
include an explanation of how the data relate to the conceptual model of
the site. It is recommended that NSCC include a description of any
patterns that relate geologically different zones with different specific
capacities. If any such patterns existed, this information would help
NSCC understand preferential pathways for groundwater movement, and
if these zones may be used to help remediate the contaminated
groundwater.
The Packer Tests were conducted to determine locations of (a) fracture
zones, (b) layers or depths where groundwater is contaminated and (c)
the extent of groundwater contamination in the bedrock aquifer. This
assists the Remedial Design. The Specific Capacities are used in the
Remedial Design to determine pumping rates from different Extraction
Wells, and the extent of drawdowns and Areas of Influence due to
pumping at different rates from different Extraction Wells.
NSCC respectfully disagrees with the recommendations of NCDEHNR
because the requested investigations are unnecessary and do not
contribute or assist the Remedial Design. These recommendations will
not be included in the RD/RA Field Investigations Summary Report.
15
- - - - - - - - - - -I!!!! 1!1.15 r:aa lilli1i - - - -
P-02
♦
PLANT EAST (ft)
C.\.:irojectslcd"pmglouJ..wp\lig 1-7. pr•
SCALE (n)
0 100 200 300 ,oo S00
■ SBA2-2
♦
NS-14
LEGEND
LOCATIONS WI-IERE REFUSAL
WAS REACHED
lilONITOAlt«i WELL
WHERE REFUSAL WAS RE.ACHED
r-OEOROCK ELEV.t. HON
CONTOUR
NA T/ONAL STARCH AND
CHEMICAL COMPANY
SALISBURY N.C.
- - - - - - --- --I!!!! !!!Iii == lilii iiiil -- -
,oo
500 -
400 ·,
0
A
~ • l " P-04
P-01
LEGEND
T Water Table ElevebOfl
c:""°jectsv;drspmg'ou3--...,:i'l,g 1-8. pre
NS-OS
NS--17
NS--25
I
NS-21
I
..
1000 2000
Oi5tance (feet)
Vertical Exeggera!Jon: 4X
NS-24
3000
~ • 8 l ~
" ~ I [ w • z 1l u
• ,ooo
A'
FIGURE 2-8
HYDROGEOLOGIC CROSS SECTION A-A'
NATIONAL STARCH AND
CHEMICAL COMPANY
SALISBURY N.C.
B
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Comment No. JO
Sect. 4.4
Response No. 10
Section 4.4
Comment No. 11
Sect. 5.2
A:\OU3RES4.AA
The tables in this section on "Groundwater Quality Results" indicate that
significant amounts of contaminants (specifically l ,2-DCA) were detected
in the l 60-200' zone in the bedrock wells NS-50, NS-52, and NS-54,
which are downgradient of the lagoons. Further characterization of the
aquifer and further delineation of the extent of contamination are
necessary.
Results of Packer Tests, sampling and analysis indicate significant levels
of contamination in Extraction Wells NS-50, NS-52, and NS-54.
Further drilling, installation of deeper bedrock wells, and sampling and
analysis might be necessary to delineate the vertical extent of
groundwater contamination in the Lagoon 2 area. NSCC proposes to
first operate the bedrock Extraction Wells and the Pump and Treat
System for six months to determine whether or not the detected
contamination in the lower depths is due to real contamination or due to
contaminated groundwater moving down from above. If the
groundwater contamination in the lower depths continues after six
months of operation, NSCC proposes to install an additional deeper
bedrock well in the Lagoon 2 area to determine the vertical extent of
groundwater contamination in the Lagoon 2 area. Please see details in
Response to USEPA Comment No. 5.
In section 5.2, titled "Results of Step-Drawdown Tests", tables 5-11
through 5-20 contain drawdown and distance measurements from
pumping and observation wells. According to these-tables, seven of the
ten wells influenced at least three observation wells. However, the
distance/drawdown plots (Figs. 5.1 through 5.9) only illustrate the two
end points used to determine the slope. The slope should be determined
from a line that best fits the drawdown data from all affected observation
wells.
Furthermore, examining the data from all the observation wells may
provide NSCC with information about preferential interconnections
(e.g., fractures) between wells.
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Response No, 11
Section 5.2
Comment No. 12
Sect. 8.1, 8.2
Response No, 12
Sections 8.1,8.2
A:\OU3RES4.AA
Drawdown data from all Extraction Wells and Observation Wells were
used to design the Extraction System and pumping rates. The distance
drawdown plots are modified to include the measured drawdowns in the
Observation Wells.
Chapter 8.0 is titled "Vertical Extent of Groundwater Contamination", and
sections 8.1 and 8.2 specifically describe Area 2 and the Lagoon 2 area,
respectively. These sections of the document report the facts of the
investigation, but contain no description of the extent of groundwater
contamination. The report should include up-to-date contaminant plume
maps/cross-sections and a discussion of the movement of the plume:
lfNSCC is to meet their objective of determining the extent of
groundwater contamination, additional characterization of the aquifer and
delineation of the contaminant plume are necessary.
NSCC could not determine with certainty the extent of vertical
groundwater contamination from the data collected during the RD/RA
Field Investigations.
Available data seems to indicate that the groundwater contamination in
depths exceeding 130 feet from the ground surface in Area 2 of the Plant
may be due to contaminated groundwater from above that depth
migrating down.
In the Lagoon 2 area of the Plant groundwater contamination below 160
feet from the ground surface may be due to actual contamination of this
groundwater.
Available data collected during the RD/RA Field Investigations do not
permit updating the Plume Maps/Cross-Sections developed from more
extensive Field Investigations conducted during the OU3 Remedial
Investigations. Because of these reasons NSCC did not present any
conclusions in the RD/RA Field Investigations Summary Report.
17
--- - - - - - - - - - - - --I!!!!!! l!!llm -
C
3:: 0
"O 3:: ~
0
----------------
FIGURE 5-2 Step Drawdown Test at NS-47
Distance-Drawdown Graph
0 ~--.-----------,--,-.....,.....,....,....,.-,-----,------,------,---,-,--,-,--,-11--t-,------,------,---,------,--.,....,..,
--1----·---·--·---___ , __ _,_ __ ·-___ _I_I_ --____ ,l---l----+---1---1--l--~·-----+--! -1-----'I-I : I ! I I --·--1-
1
--·· -----· -· ___ ,_ -- - ---, -----·---------__ ,_ -_ _I __ __I __ _I_
- -... --.
-14 ~----~~---'---'---'--'-'-----''----'-
. l I
0.1 1 10 100 1000
Distance from Pumped Well (ft.)
I ■-58 Min.)
- - - - - - - - - - - - ---l!!!!!!!!I I!!!!! !!!!It -
FIGURE 5-4 Step Drawdown Test at NS-49
Distance-Drawdown Graph
0 ----------------,--,-.,....,.....,....,..-,------,----,--,--,--.--,--ft,,_...,...,...,........r,--,........,--,---,--,--,-, ~~ ~ .. : i II
-10 ---··-·-
C 3: 0 -20 -
"O
3: rn ~
0
•
◊
lJ
--·-·-··--·--------·-·· ·---· ....
I ' ti i i I , I
Al
-~ ~ u
C1j ·---1··
I --. -; -. j
------·---·-.. -· ----·--~ ----------i--..... .
i I
' . ·1
I
I I
-40 '-----' --'----'---'---"--'-' -'-,...._----'---'--'----'-'---'-'--'--'-----'---'---'--'--'-'-'-'-'---....... -'---'---'--'c...;...-'--'-'
0.1 1 10 100 1000
Distance from Pumped Well (ft.)
[ ■ 60 Min.
---◊ 120 Min. A 180 Min. o 240 Min. I
- - - - - - - - - - - - - - - -l!!!!l!I !!!!!!I l!!!!!I
C
FIGURE 5-5 Step Drawdown Test at NS-50
Distance-Drawdown Graph
0 ~--,----,-----,-~,-~-----------·----,-----,----,----,--,-,-,-llml!-, -' r-_____ r ------------_________ _1_, ____ ---------·'-
i
1--------- ----1----'--■
-50
◊
~ -100 ,---·~----··-----------·--------------· ----------··---··-·--·-----··--·---·--·---· --·-----1
-0 ;;:
~ 0
-150 !----,~·---------1----1--0 -----·----·-··-------_(-__ --·· --·--,---·---·-· --
-200 ~-----'--'-'-...;_'-'-'-----'---'-_..:.,_..:.,_-'-_:_:__J__ --'---'--'--'-..l.-:-'-'-'----'---"----'--'--'-'-...:....:....J
0.1 1 10 100 1000
Distance from Pumped Well (ft.)
I ■ 60 Min. ◊ 120 Min. 1,,. 180 Min. [J 240 Min. I
-------------------------
- - - - - - - - - - - - - - - --l!!!!I !!!!!!I
FIGURE 5-6 Step Test at NS-51
Distance-Drawdown Graph
0 ~-----------------------------,--,--,--,._.-,-.,....,., __ ---rn-f,-----,--,--,-...,...., I,: I I ■
<> I <> <>
-------------------f----_L __
-20 --------■-----------
-40 __ J_ --------------------------------
-60 '------'----'---'---'--'------'---...!...'-L----'---'--------'-'----'---'-'---'----'---'----'---'---'-'--'-..:....C.-------'---'---'---'-------'---'---...!....!..J
0.1 1 10 100 1000
Distance from Pumped Well (ft.)
- - - - - - - - - - - - - - --!!!!!I I!!!! 11!1111
~ ~
C ;:
0 -0 ;:
"' ~
0
FIGURE 5-7 Step Test at NS-52
Distance-Drawdown Graph
0 ~---------,-------,--,---~,-~-----,,----;--,---,-----,-,---,-!"!,----O--ffl---,--,----,------,--,-,--,-,
I I ! • ~4 ~ -I I i
r I i!. I ! <> !---i --------i------·--·------------~ -------------i·-i-----i-
-------------------; I I I i
-40 -----------·-· ---~---------_-__ , ~~-_-___ -____ , _____ -_ ~ ~ -~ ~~~~~ -___ -_ ~----~ ---~-~~---~ ~~~~:~~~~~--/----------'-_ = ~[~ --
I _,_, __ ,_ ------------t-l-1-------I ---
___ ---. -----------·--· ----------.. ------+----I--•------f------C-1~-'-1-7--
-20 ---------·-------
-60
-80
------------------------I
◊
-100 --I -
I ------------------------------------------•---1-----------------·-1----__ T _________ ------------------
-120 '--------'---'---'---'--'---'--J. .!..I..----'---'--I I I
0.1 10 100 1000
Distance from Pumped Well (ft.)
I ■ 60 Min. ◊ 120 Min. I
- - - - - - - - - - - - - - - -I!!!!!! l!!!!!I !!!!!II
FIGURE 5-8 Step Test at NS-53
Distance-Drawdown Graph
------------------
0 ,----,----------------~~--------,-----,---,-----,---,----,--,--,-,------,--,~1-:----,----,---,---;-:-:-,
I T"I
..... -. ■-·
-10 --------·-----------·····----·-.. --· .. -·-----------
◊
! __ _]__ -.
-20 ----;
-30 '------'-----'--'---'--'--C..:..'-'------'-----'--'--'--'--'-'--'-'--
0.1 1 10
Distance from Pumped Well (ft.)
,:-IJ '
1◊
:6.
•
<>
-[-~ ---
□
_I
--------1 ·· . ---·-----~ -----
1 '
100
I ! I
1000
-- - - - - - - - - - - - - - -II!!!!! !!!!I 1!!111!1
~
FIGURE 5-9 Step Test at NS-54
Distance-Drawdown Graph
0 ~--.---------~-~ ---,---~~--~-~--r.1,i_..,....., __ --,-____ .,........--,---,-.,-,-...,....,...,
i I ! ''-' ~, ~ -
■ I l I ': 1----+---1--l ___ -- ---!------+-----------------_,_I_L__._, -------·• -i---·-◊ I '
-50 __ ,., __ ··---------.. , .. ,_ --1----------------- - _ _I_ -------_, __ ----L----'--------·-----i_ --
:S • i -100 ------_ .. ______ I __ --------
j
l:! 0
-150------__ I J
--------r---·--------------·---------
i -- .
I I , I
I
-200 '----'----'--"--'-'--'-' --'-'-----'---'---'----'----'-'--'-'--'-----'----'-----'--'-----'-'--'-'----'----'---'----'--'--'---'--'-'
0 .. 1 1 10 100 1000
Distance from Pumped Well (ft.)
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A:\OU3RES4.AA
If it becomes necessary, NSCC will conduct additional drilling and
installation of deeper bedrock wells in both Area 2 and the Lagoon 2
area. However, NSCC plans to conduct these additional drilling and
installation of deeper bedrock wells after operating the Groundwater
Extraction System for six months to ascertain that the detected
groundwater contamination in the lower portion of the bedrock is real
and not temporary.
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Responses to NCDEHNR Comments (05/09/97) on the
Remedial Design/Remedial Action Conceptual Design Report
for the Third Operable Unit (OU3)
Comment No. 1
Sect. 3.1
Response No, 1
Section 3.1
A:\OU3RES4.AA
National Starch & Chemical Company
Cedar Springs Road Plant, North Carolina
This section, titled "Design Basis", states that 120,000 gallons of
contaminated groundwater will be pumped from the new extraction wells
for OU3. NSCC should specify that the proposed extraqion rate is
120,000 gals/day.
This portion of the draft design report also states that"[A]t this rate of
pumping the groundwater extraction system is expected to have an area
of influence covering the contaminated groundwater plume". It is
recommended that NSCC amend or omit this sentence for the following
reasons: l) in the draft RD/RA report, NSCC demonstrates that the
extent of ground-water contamination has not been delineated; and 2) the
10 extraction wells have not pumped simultaneously to evaluate the
cumulative effect that the system will have on the aquifer.
Consequently, NSCC has not provided information to substantiate this
claim about the performance of their ground-water extraction system.
The Design extraction rate is indeed 120,000 gals/day. Correction is
made to indicate proper unit.
NSCC respectfully disagrees with NCDEHNR's recommendation to
delete the statement on Areas of Influence covering the two Contaminant
Plumes. NSCC's statement for extraction rate is based on computer
analysis and simulation of cumulative drawdowns and Areas of Influence
in Area 2 of the Plant and the Lagoon 2 area using data collected during
the RD/RA Field Investigations. Table 3-2 presents the calculated
cumulative drawdowns at the ten Extraction Wells under design pumping
rates. Figure 3-2 illustrates the Area of Influence of pumping in Area 2
of the Plant while Figure 3-3 illustrates the Area of Influence of
pumping in the Lagoon 2 area under design pumping rates and
conditions. Based on the above information NSCC believes that the
statement is correct.
19