0104_AlamanceCoCDLF_MW5Mon_DIN28665_20171129

November 29, 2017

Sent Via Email – [e-mail]

Mr. Richard Hill
Alamance County
Department of Solid Waste
2701 Austin Quarter Road
Graham, NC 27253

Re: Monitoring Well MW-5
Alamance County Construction and Demolition Landfill
Solid Waste Permit Number 0104
DIN28665

Dear Mr. Hill:

The Solid Waste Section (Section) has completed a review of your correspondence
summarizing the October 4, 2017 meeting that occurred at the facility. The meeting was
conducted to discuss the status of the compliance monitoring well network. Vinyl chloride has
been reported at concentrations above the standards established in 15A NCAC 02L 0202 (2L
Standards) in MW 5 and MW-5R was installed approximately 70 feet downgradient to define
the extent of contamination. The October meeting was held to determine the next course of
action.

As discussed during the meeting and summarized in your correspondence, if there are no 2L
Standard violations during the October 2017 Appendix II monitoring event in MW-5R, MW-6,
or MW-7, then MW-5 is the only monitoring well that needs to be monitored annually for
Appendix II constituents. If contaminant concentrations are reported above the 2L Standards
in any of the wells other than MW-5, then Appendix II sampling will continue semi-annually on
all wells for at least two more sampling events. After those two sampling events, the
monitoring wells with 2L Standard violations will be monitored for Appendix II constituents
annually. If an Appendix II constituent is detected during Appendix II monitoring, the detected
constituent(s) must be analyzed in samples from the well where the detection was reported on
an annual basis. For example, the first semi-annual event would require Appendix II monitoring
in the well(s) with 2L Standard violations and the second semi-annual event would require
Appendix I monitoring plus Appendix II detects in the designated wells. Alamance County is not
required to conduct additional assessment or initiate corrective action at this time since there
are no 2L standard violations at or beyond the compliance boundary.

Assessment activities will be required if contaminant concentrations exceed the 2L Standard in
additional wells during future groundwater monitoring events. 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 919.707.8288. Thank you for your cooperation with this matter.

Sincerely,

Ervin Lane
Compliance Hydrogeologist
Solid Waste Section, Division of Waste Management

Wayne Sullivan, Municipal Engineering Services Co., PA
Jason Watkins, Field Operations Branch Head
Deb Aja, Western District Supervisor
John Patrone, Environmental Senior Specialist