5504_LakeNormanCDLF_ASDResponse_DIN28510_20171031

S t a t e o f N o r t h C a r o l i n a | E n v i r o n m e n t a l Q u a l i t y | W a s t e M a n a g e m e n t
1 6 4 6 M a i l S e r v i c e C e n t e r | 2 1 7 W e s t J o n e s S t r e e t | R a l e i g h , N C 2 7 6 9 9 -1 6 4 6
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ROY COOPER
Governor

MICHAEL S. REGAN
Secretary

MICHAEL SCOTT
Director October 31, 2017

Sent via email – [e-mail]

Mr. Mike Gurley
Republic Services Inc.
5105 Morehead Road
Concord, NC 28027

RE: Alternate Source Demonstration - Request for Additional Information
BFI Lake Norman Construction & Demolition Landfill
Permit 5504-CDLF-1999
Lincoln County
DIN 28510

Dear Mr. Gurley:

The Solid Waste Section (Section) has completed a review of the March 15, 2017 Groundwater Alternate
Source Demonstration (ASD) report (DIN 28508) submitted for the referenced facility by Jett
Environmental Consulting (Jett) on behalf of BFI Lake Norman Landfill, Inc. The ASD addresses
groundwater compliance exceedances of total iron and total manganese above the 2L Groundwater
Standards established in 15A NCAC 02L .0202. These exceedances have been detected during Detection
Monitoring in downgradient compliance wells MW-2, MW-3, and MW-5.

The ASD submittal included time series graphs, surface water to groundwater data comparisons,
dissolved/total metals analysis comparisons, and geochemical indicator parameter data analysis. The ASD
report concludes that, based on the multiple lines of evidence presented, the elevated iron and
manganese levels are due to natural variation in groundwater quality and are not attributed to the landfill.

Based on our review of the ASD, the Section is requiring additional information to be submitted, in a
phased approach if applicable, as an ASD Addendum. The Section is requesting BFI Lake Norman Landfill
Inc. address the following in the ASD Addendum:

• Provide time series graphs for the complete period(s) in which groundwater data has been
collected from the facility’s monitoring wells, including data from recently abandoned well MW-
4. Groundwater sampling has been conducted in the detection wells since 1999 when the facility
was first constructed. Attachment A of the report contained time series graphs for iron and
manganese from wells MW2, MW-3, and MW-5 only for the 2010-2016 period. An analysis of the
full set of data can provide a more accurate indication of historical trends in groundwater quality,
including any seasonality influences. If the pre-2010 data is not used, please provide justification
for exclusion from the trend analysis.
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• The facility’s downgradient monitoring wells (MW-2, MW-3, MW-4 abandoned, and MW-5) are
all located in the floodplain of the adjacent Forney Creek. Based on their proximity to the creek
and the water level elevation data, the report points to the likely hydraulic connection between
the stream surface water flow and the shallow surficial aquifer in the vicinity of the wells. The
report further states that the iron and manganese data from the upgradient background well
MW-1 may not be comparative to data from these downgradient wells due to this hydraulic
interaction. Therefore, the facility may need to install an additional background well in a similar
hydrological setting as the downgradient wells to calculate background for iron and manganese
and to determine whether the reported exceedances are due to naturally occurring background
or to the landfill.

• In September 2015, a groundwater sample from MW-5 was collected and analyzed for both
dissolved iron and total iron. The dissolved iron concentration (63 ug/L) was significantly lower
than the total iron concentration, and approximately five times lower than the 2L standard of 300
ug/L. Given the difference in total versus dissolved results, please provide turbidity data for the
sample to evaluate whether turbidity is influencing the higher total iron result. Samples derived
from turbid samples may not accurately represent conditions for constituents that are mobile in
groundwater as it is difficult to differentiate between sediment that represents formational
material versus mobile particulates or precipitates (May 13, 2013 Aquifer Protection Section
Memorandum, Subject: Aquifer Protection Section Policy for Metals Determinations Required by
Title 15A NCAC Subchapter 2L). Further, dissolved samples may represent a false negative bias
due to potential filtering out mobile colloidal particles and precipitates. For these reasons, the
Section does not accept substitution of dissolved metals results in place of total metals for
compliance: however, this data may be useful in conjunction with other lines of evidence.

Within 120 days of receipt of this letter, please submit an ASD Addendum that addresses Section
comments above and meets the criteria described in the guidance document titled NC Solid Waste Section
Guidelines for ASD Submittals for Solid Waste Management Facilities. Upon submittal of this information,
the Section will evaluate the ASD Addendum and make a determination on the ASD request. Be advised
that additional information or analyses may be requested to fully evaluate and support an ASD for the
constituents of concern. Additional requirements consistent with the ASD Guidance may include, but are
not limited to, determination of site background levels, statistical analyses, review of sampling
procedures, or other means necessary to establish the landfill has not contributed to groundwater
standards exceedances.

Please note that if Lake Norman Landfill Inc. decides not to submit an ASD Addendum, the facility will be
required to initiate Assessment Monitoring in accordance with 15A NCAC 13B .1634.

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If you have any questions or concerns regarding this letter, please feel free to contact me by email at
[e-mail] or by phone at 919.707.8258. Thank you for your continued cooperation with
this matter.

Sincerely,

Perry Sugg, PG
Permitting Hydrogeologist
Solid Waste Section, Division of Waste Management
NCDEQ

Cc: Ellen Lorscheider - Solid Waste Section Chief, NC SWS
Jason Watkins - Field Operations Branch Supervisor, NC SWS
Ed Mussler, PE - Permitting Branch Supervisor, NC SWS
Larry Frost - Permitting Engineer, NC SWS
Jackie Drummond - Compliance Hydrogeologist, NC SWS
Kim Sue - Environmental Senior Specialist, NC SWS
Steve Jett, LG - Jett Environmental Consulting