INTERNATIONAL
TECHNOLOGY
CORPORATION
April 4, 1995
IT Project No. 409440
Caroline Kwan, Project Manager
New York/Caribbean Superfund Branch 2
U.S. EPA Region II
290 Broadway, 20th Floor
New York, NY 10007-1866
Comments on "Draft Feasibility Study"
Tutu Wells Site. St. Thomas. U.S. Virgin Islands
Dear Ms. Kwan:
Please find enclosed three copies of IT Corporation (IT) comments on the above referenced
document. These comments are being provided on behalf of our client, L'Henri, Inc. These
comments are also being transmitted to the TEIC Committee; however, there is no mechanism
currently in place for these comments to be addressed by TEIC. We believe that these comments
should be addressed before the document can be finalized.
We appreciate this opportunity to present our concerns on behalf of our client. If you have any
questions, please feel free to call Attorney D'Anna at (809) 776-6533 or me at (615) 690-3211.
Sincerely,
TV-
Belinda K. Price, R.P.G.
Project Manager
Enclosure
cc: 
N. D'Anna, Esq.
P. Martinez-Lorenzo, Esq.
Jack McBirney, de maximis, inc.
CO
-0
c:\ss\Api\BPooi\w 
Regional Office
312 Directors Drive • KnoxviUe, Tennessee 37923-4799 • 615-690-3211 • FAX: 615-690-3626
IT Corporation is a wholly owned subsidiary of In temational Technology Corporation
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Comments on Geraghty and Miller, Inc. 1995,
Draft Feasibility Study Tutu Wells Site,
St Thomas, U.S. Virgin Islands
Section 2.1.1.3. Groundwater flow direction is still not sufficiently well understood in the
deep bedrock aquifer in the southern portion of the Tutu "site"ie south of the Esso station.
No measured groundwater elevations were used between the locations SW-6, MW-21D,
MW-22D and west of these wells, an area of 1,000 ft x 1,500 feet. Groundwater contours
representing deep bedrock groundwater flow beneath the following properties should be
dashed: O'Henry laundry, Liquor Barn, and Archies Welding. The map included in Graves
and Gonzales 1988, used as justification for the "generalized regional flow" presented by
Geraghty and Miller, indicates a lower level of detail (contours are shown at no less than
ten foot intervals) than included on figure 2-4 (contours are shown at five foot intervals).
It is not appropriate to use the 5 foot contour intervals. In addition, the Graves and
Gonzales map uses "dashed" (indicating approximately located) and "queried" (indicating
uncertain) contours over much of the area and particularly the area to the south and
southeast of the O'Henry laundry. Further, the text included in Graves and Gonzales 1988
states "Several wells were being pumped, or had just terminated, when the water levels were
measured ...These water levels reflect a pumping or recovery condition; therefore, static
water-level conditions throughout the Turpentine Run basin at the time of measurement
cannot be assumed". Because the flow map presented by Geraghty and Miller (figure 2-4)
shows a non-unique solution, the positioning of the recovery wells RW-2, RW-3 and RW-5
may be inappropriate. Also, please explain why data from MW-22D is included on both the
shallow and deep flow maps.
Section 2.2.2.1. First Paragraph. Since there is no such compound as "Total chlorinated
VOCB,the shape of each individual VOC compound plume should be discussed. The edges
of the plumes should be defined as the drinking water standard (DWS) for each individual
compound (where a DWS exists). What is meant by "The southern plume originates near
the O'Henry Dry Cleaners"? Regardless of the current location of chlorinated VOCs in the
groundwater, the origin of these chlorinated VOCs in groundwater south of the O'Henry
property is unknown.
Third Paragraph. According to the shallow bedrock groundwater flow map presented
in figure 2-3, monitoring well OHMW-04 is located sidegradient to the O'Henry Dry
Cleaners not downgradient as stated in the text.
Section 3.4.2. The practicality of a centralized groundwater treatment system and use of
POET systems on domestic and commercial wells is questionable. The use of a centralized
groundwater treatment system will require piping from one end of the Tutu area to the
other with associated problems due to the hilly nature of the site. This brings up questions
of access, liability if pipes leak or are damaged, and maintenance. Likewise, future liability
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is a potential issue if monitoring indicates that contaminants are present in the effluent
water of a permitted domestic or commercial wells. These issues should be very carefully
considered before including a centralized groundwater treatment system and POET systems
on domestic and commercial wells as part of the site remedy.
Section 4.4. Since the FS apparently chooses two alternatives (SWRAs 4 and 7) which is
the SWRA advocated?
Section 4.5. The following activities are recommended to be included in the pre-design
activities (and costs):
Pre-design work plan and reports of work performed.
Placement of additional deep bedrock monitoring wells in the area identified in the
comment on section 2.1.1.3 above and additional groundwater level monitoring
including wells not currently included on the flow maps to determine whether the
assumed groundwater flow south of the Esso station is correct.
Groundwater modeling should be conducted to explore the limits of contaminant
movement and to demonstrate that the proposed groundwater extraction well
scenario will effectively capture the plume. Because of the uncertainty in flow
direction in the area south of the Esso station it is recommended that a sensitivity
analysis be performed assuming a southwesterly flow direction to the Kentucky Fried
Chicken property and a southeasterly flow direction thereafter to test the recovery
well scenario if Geraghty and Miller are incorrect in their interpretation of flow
direction.
Figure 4-7. Areas marked as suspected to contain DNAPL do not appear to be consistent
with the contaminant plumes drawn. For the area drawn near the O'Henry Dry Cleaners,
the DNAPL plume extends outside the 10 ppb "total VOCs" contour. Please explain the
rationale for the extent of the suspected DNAPL areas shown.
The locations of recovery wells should take into account the presence of individual
compounds of concern (not just the "total VOC plume"). By considering just the "total
VOCs" the recovery wells may not be appropriately located. Individual compound maps
should be presented and an analysis as to the appropriateness of the recovery well network
to recover the individual compounds of concern should be addressed.
Why does the map list only selected data for selected wells. Explain the rationale for only
presenting certain data. In addition, it appears that not all of the available data has been
used to construct the "total VOC" plume, for example data for MW-15 has not been
incorporated. Please explain.
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Comments on Cost Estimates Provided. Note that a detailed review was performed of the
cost estimate for SWRA 4 (Table 4.9) because this was the (assumed) preferred alternative.
Comments on this cost estimate are also applicable to other SWRA cost estimates.
The following are comments on the Groundwater Treatment Capital Cost:
The unit cost for Deed Restrictions seems low.
Explain what is included in Site Preparation/Mobilization. 
How many locations are
included? (ie does it include site prep for the treatment system location, piping
locations and recovery well locations?)
Clarify how many wells are included in Well Abandonment. How will the wells be
abandoned. Does the cost include work plan and reporting requirements?
Does Site Acquisition mean purchase or lease? Is it for the site for the groundwater
treatment system only or does it include piping locations and recovery well locations?
If land is to be purchased, what will be final disposition after the end of the
remediation. Also does the O&M costing include any taxes to be paid.
A detailed breakdown of the Groundwater Extraction System costs should be
provided. Does this also include the trenching and filling for underground piping
installation for piping to the centralized treatment system? If so, how will leak
detection be accomplished?
What is included in Pre-Treatment? A scale inhibitor and metals treatment should
be included. In addition, a bench-scale test will be required to estimate the chemical
dosage so that adequate pre-treatment is performed.
Does the cost for the Low Profile Air Stripper include installation? The cost
provided seems low for two air strippers in series.
Does the Liquid Phase Carbon Treatment System include one or two beds?
How many Process Pumps are included and are these Process Pumps and Piping and
Discharge Pumps and Piping just for the treatment system? State how many pumps
and the length of piping.
What is the assumed size of the Aboveground Storage Tank? Does the unit cost
include shipping and installation?
Make sure that the cost for the Treatment Building includes cost for a foundation.
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Is Electric for just the central treatment system or for the i
Each of the POET systems may need individual design. For
individual design for electrical work and housing.
The following are comments on the Soil Treatment Capital Cost-
The cost of Excavation/Disposal, Site Restoration and E:
Analysis is much too low. Will individual Corrective Actioi
Does the cost include preparation of reports? How will the
would be much more practical to build soil venting piles or to
treatment of excavated soils. How many samples will be colic
analyses will be performed? Does the cost include data valida
should be broken down on an individual site basis.
Why is the cost for the SVE system at the Curriculum Center i
the other sites? Detail should be provided for each site such a*
blowers, number of extraction wells, piping details, treatment
installation cost.
Does Engineering include detailed design, material balanc
preparation of specifications and bid packages?
Does Construction Supervision include installation of the system:
a Health and Safety Officer at the site during construction?
The following are comments on the Operations and Maintenance Cost:
Where is the cost included for an Operations and Maintenance P
O&M cost should be included for the domestic and commercial '
POET systems. This should include scheduled maintenance, samplin
How many and which wells are included in Groundwater Moniton
wells, monitoring wells, domestic and commercial wells)? Does the i
semi-annual reports? 
Does the cost include Quality Control sar
validation?
The Electricity will supply approximately 30 Hp. Is this just for the tn
or does it include recovery wells also?
Does the cost for carbon replacement include the disposal of spent c
Does Treatment System Monitoring include both air and water samf
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and effluent)? 
What will they be analyzed for? Does the cost include Quality
Control samples and data validation? Does the cost include reports?
Does Administration include data reporting or is it just project management?
Does Equipment Replacement include installation cost?
In addition the following observations are made concerning the cost buildup:
Pre-design activities as described in Section 4.5 have not been included in the cost
estimates. For example SVE pilot test, bioventing pilot test if appropriate, air
stripper pilot test, and metals removal pilot test should be included in the cost. This
appears to significantly underestimate the final cost of remediation.
Cost does not appear to include: preparation of plans, O&M manuals and reports;
start up costs; licenses, permits and legal fees; insurance and bonds.
Shipping and travel may be underestimated.
Demobilation 
and decommissioning of recovery wells, SVE systems and the
groundwater treatment plant should be included. In addition, closure and post-
closure activities should be included in the cost.
Cost should be included for air emissions evaluation and permit application.
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