WI0300435_Staff Report_20200626 (2)

Date: 06/26/2020
Permit No. WI0300435
County: Gaston
To: UIC CO Permitting_
Permitee/Applicant: (Owner)_Duke Energy Carolinas, LLC
Central Office Reviewer Michael Rogers Facility Name: Allen Steam Station
L GENERAL INFORMATION
1. This application is (check all that apply): ® New ❑ Renewal
❑ Minor Modification ❑ Major Modification
a. Date of Inspection: No site visit was performed for the staff report. The report was generated based on
site historical knowledge and submitted documentation.
b. The person contacted and contact information: Scott Davies, P.G., Duke Energy (980)-373-6563
c. Site review conducted by Edward Watson, Hydrogeologist & Joanna Harbison, Hydrogeologist
d. Inspection Report Printed from BIMS attached: ❑ Yes ® No.
e. Physical Address of Site including zip code: 253 Plant Allen Road, Belmont, NC 28012-8845
f. Driving Directions if rural site and/or no physical address: Access via NC 273
II. DESCRIPTION OF INJECTION WELLS) AND FACILITY
1. Type of injection system:
❑ Geothermal Heating/Cooling Water Return
® In situ Groundwater Remediation
❑ Non -Discharge Groundwater Remediation
❑ Other (Specify:
2. Provide well construction information from well tag: TBD after wells have been completed.
b. Does the proposed system use the same well for water source and injection? ❑ Yes ® No
If No, please provide source/supply well construction info (i.e., depth, date drilled, well contractor, etc.) and
attached map and sketch the location of supply well in relation to the injection well and any other features in
Section IV of this Staff Report. Proposed well construction details are provided in submitted material, Table B-1
and figures B-1 and B-2.
3. Does the map included in the Application reasonably represent the actual site (property lines, wells, surface
drainage)? ® Yes ❑ No. If No, or no map, please attach a sketch of the site. Show property boundaries,
buildings, wells, potential pollution sources, roads, approximate scale, and north arrow.
0 Site is well mapped, but the site map does not display the fresh water intake from the Catawba River
for injection well water source.

III. E VAL UA TION AND RECOMMENDATIONS
1. Do you foresee any problems with issuance/renewal of this permit? ❑ Yes ® No. If Yes, explain.
2. List any items that you would like WQROS Central Office to obtain through an additional information request.
Make sure that you provide a reason for each item:
Item
Reason
I
Detail how the injection pressure be managed to avoid creating preferential
pathways.
2
Detail how the quality of the source water has been assessed and how it will be
monitored/maintained so that COIs and unrelated contaminants are not introduced
into the subsurface at concentrations that may exceed 2L standards.
3
There needs to be a reference to the monitoring associated with the proposed
injection the IMP/EMP .
4
Detail how backwash from the filter/UV system is managed.
5
A number of injection and recovery wells are in areas with potential traffic
concerns, is the vault construction sufficient to protect the well heads? Is there a
plan to include reinforced concrete to the well pad concrete to accommodate
heavy equipment traffic?
6
Detail the timing of how injection wells will be installed in and near the coal pile
area relative to removal of the coal pile so that the wells can be drilled and
maintained (this includes the slanted wells).
7
The application does not clearly define where the water for the injection wells is to
be drawn from. Please submit a modified site map to indicate the location of the
fresh water intake.
8
The UIC application does not state the COI s. Please submit COI information.
COIs are referenced in other documents, but not in the UIC application.
3. List specific special conditions or compliance schedules that you recommend to be included in the permit when
issued. Make sure that you provide a reason for each special condition:
Condition Reason
1
2
4. Recommendation
❑ Deny. If Deny, please state reasons:
❑ Hold pending receipt and review of additional information by Regional Office
® Issue upon receipt of needed additional information
❑ Issue

5. Signature of Report Preparer(s): Edward Watson 06/26/2020.
Docu Signed by:
A4,4c,W H P44,f . 6. 29. 2020
F161 FB69A2D84A3...
Signature of WQROS Regional Supervisor: Date:
IV. ADDITIONAL REGIONAL STAFF REVIEW COMMENTS/ATTACHMENTS (Optional / If Needed)
Notes regarding MRO review including references to other reports:
Detail on how the backwash be managed? Here is the specific wording from the Allen CAP update "Liquid
waste materials generated as a result of maintenance (e.g., filter backwash or wash water) would be directed to
the plant drain system for treatment and management. The equalization tanks, treatment system, transfer
pumps, and holding tank would be housed in an enclosed structure to prevent exposure to prevailing weather
conditions. " Pg 222 (6-134)
EMP reference? The EMP will be implemented 30 days after CAP approval, and will continue until there is a
total of three years of data confirming COls are below applicable standards at or beyond the compliance
boundary, at which time a request for completion of active remediation will be filed with NCDEQ.
EMP elements include reporting evaluation and schedule, groundwater monitoring well systems, sampling
protocol, frequency, and parameters. This is taken from the Allen CAP. Section 6.8.5. It was noted by MRO that
the IMP would need to remain in effect until the implementation of the corrective action measures and not
approval of the plan. Figure 6-33 (Effectiveness Monitoring Well Network and Flow Paths)of the Allen CAP
shows all the wells to be included in the EMP. The figure in the application shows wells to be sampled but does
not designate which ones are to be sampled for the EMP.
Water used for clean water infiltration will be obtained from the Catawba River. Water supplied to the clean
water infiltration wells is non potable water that is suitable for infiltration as part of the remediation process
and not for consumption. The existing raw water intake would be used. The intake is located along the west
bank of the Catawba River on the east side of Duke Energy property near the power block. Raw water would
travel through the existing plant distribution system to an infiltration water treatment plant. The treatment
system would condition the water prior to storage and distribution to the clean water infiltration wells.
This is taken from the Allen CAP under Clean Water Infiltration Water Treatment pg 221 (6-133).

It should be noted on the figure in the UIC application where that intake is located along with the location
of the fire water force main line tie in.
The related RWpermit for the pilot test is WR030011 S, discharge from the system will be captured under
NPDES permit NC0004979.