0104_AlamanceCoMSWLF_MW50RMon_DIN28666_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: Monitor Well MW-50R
Alamance County MSW Landfill
Solid Waste Permit Number 0104
DIN28666

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 in
MW-50R and MW-BG was installed as the replacement background well for the facility. The
October meeting was held to determine the next next course of action.

As discussed during the meeting and summarized in your correspondence, MW-50R should
have been included in the October 2017 semiannual monitoring event. If 2L standard violations
are reported in MW-50R and/or another well during any subsequent monitoring event, all wells
included in the compliance monitoring network should be sampled semi-annually for at least
two events for Appendix II constituents. 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 Appendix I monitoring in the remaining wells. 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. As also discussed during the
meeting, Phase 3 construction cannot begin until contaminant concentrations are below the 2L
Standard in MW-50R. 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
Jason Watkins, Field Operations Branch Head
Deb Aja, Western District Supervisor
John Patrone, Environmental Senior Specialist