WS-2871_7246_CA_O_20240703

1
Gene Mao
From:Gene Mao
Sent:Wednesday, July 3, 2024 9:30 AM
To:Edmund Q B Henriques
Subject:RE: McLeansville Fire Dept., #7246
Ed,

I discussed with James last Thursday about your assessment of AS/SVE system at the
subject site. Based on the system conditions and contaminant levels, James said that the
trust fund will not approve the fund for repair and reactivation of the system. So, you can
continue annual monitoring.

Please submit an ePATA for abandoning the AS/SVE wells to avoid the annual fees for
them.

I have not received any ePATA for removing remediation system from any UST site. If
you’ve removed any remediation system from a Trust-fund UST site, please share your
experience, and we can work together to address the system removal.

Thank you.

Gene Mao
Hydrogeologist
Public Health

Guilford County Government
400 West Market Street, Greensboro, NC 27401
336-641-3589 | m: 336-451-7638 | f: 336-641-4812
[e-mail] | www.guilfordcountync.gov

From: Edmund Q B Henriques <[e-mail]>
Sent: Wednesday, June 26, 2024 4:08 PM
To: Gene Mao <[e-mail]>
Cc: Cody Austin McMechen <[e-mail]>; Tommy Gregory <[e-mail]>
Subject: FW: McLeansville Fire Dept., #7246

*WARNING* This email originated outside Guilford County's email system.
*WARNING*
Do not click unrecognized links or attachments. When in doubt, use the Phish Alert
Report button.
2
Good afternoon, Gene. Wayne passed along your email to me, so my responses are provided below.

Monitoring well MW-8 was historically abandoned. My recall is that MW-9 was reported by the owner as destroyed
during construction of the then new building. Since the well was never found it should be deemed abandoned for
the records. Well MW-7 was the site’s deep monitoring well, it was converted into ASW-1 following approval of the
CAP.

S&ME made a site visit on April 23, 2024, to perform a general assessment of the condition of the former air sparge
(AS) / soil vapor extraction (SVE) remediation system.

 There was no electrical power service to the system.
 The SVE blower could not be turned by hand, thus deemed seized.
 There was no way to check the serviceability of the air-compressor without electrical power. Based on our
experience with other AS system shut down for extended periods of time, the McLeansville air-compressor
is likely non serviceable having been shut down for over 20 years.

The following is a short list of what we anticipate being needed to bring the AS/SVE system back online. With the
relatively low dissolved petroleum concentrations, air-sparge alone should be a reasonable option for treatment
of the current groundwater conditions.
 Reestablish electrical service with Duke Energy
 Remove and replace old compressor with a new air-compressor unit. This is the only high-dollar ticket
item.
 Replace flow rate controllers, flow pressure controllers, above grade airlines, and other miscellaneous
items.
 It is possible that the operations controlled by the PLC that operated the original system, could be replace
with a basic low-cost timer controller. This would avoid the need to have a programmer involved. We have
done this on a few hot-spot remediation sites.
 The existing sparge wells should be functional. We would need to check for underground air-line leaks.

Based on historic data, we know that AS was very successful at bringing down the VOC concentrations. There was
some rebound of VOC concentrations after the system was turned off, having met the benzene 100 ug/L target for
the transition to MNA. S&ME requested reactivation of the system to address rebound conditions, but never
received approval to reactivate the system. We see both sides of the debate.

As far as alternative cleanup options, two additional soil borings were performed in 2016. Analytical results did
not detect petroleum impacted soils with concentrations greater than the method detection limits. Thus, we have
no recognized targets for a source area soil removal action, as a tool to enhance MNA. We cannot rule out that
additional soil sampling may yield the discovery of a residual soil source area. Performance of some type of
injection event to stimulate remediation is certainly an option; however, without the collection of additional site
assessment data that injection vendors typically require, the performance of an injection event cannot be
accurately forecasted. Accordingly, reactivation of the sparge system appears to be the better remedial option. If
so, a New Technology Cleanup Plan, as requested by NCDEQ does not appear needed since the technology
would not change.

Would you and James Brown be open to a meeting to discuss the pathway forward, with S&ME and McLeansville
FD?

Kind Regards, Ed

\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
Edmund Q.B. Henriques, L.G. //
3
Principal Geologist

S&ME
8646 West Market Street, Suite 105, Greensboro, NC 27409
M: 336.312.3330 // O: 336.288.7180
www.smeinc.com

From: Wayne Watterson <[e-mail]>
Sent: Wednesday, June 26, 2024 1:37 PM
To: Edmund Q B Henriques <[e-mail]>; Lyndal Butler <[e-mail]>
Subject: Fw: McLeansville Fire Dept., #7246

I assume you know the answers to Gene's questions.

\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
Wayne Watterson, P.E.
Principal Engineer

S&ME
8646 West Market Street, Suite 105
Greensboro, NC 27409 map
M: 336.908.7653 // O: 336.288.7180
www.smeinc.com
LinkedIn // Twitter // Facebook

This electronic message is subject to the terms of use set forth at www.smeinc.com/email. If you received this message in error, please advise the sender
by reply and delete this electronic message and any attachments. Please consider the environment before printing this email.

From: Gene Mao <[e-mail]>
Sent: Wednesday, June 26, 2024 1:34 PM
To: Wayne Watterson <[e-mail]>
Cc: Sharis Bratton <[e-mail]>
Subject: McLeansville Fire Dept., #7246

Wayne, An audit on the monitoring wells at the subject site indicates that there are 9 MWs, 3 ASWs and 2 VEWs. ASWs and VEWs are not in the permit. I think probably not because your latest monitoring report recommends re-activating the AS/SVE system. Have these remediation wells
4

Wayne,

An audit on the monitoring wells at the subject site indicates that there are 9 MWs, 3
ASWs and 2 VEWs. ASWs and VEWs are not in the permit. I think probably not because
your latest monitoring report recommends re-activating the AS/SVE system. Have these
remediation wells been abandoned?

There have 9 MWs (MW-1 to MW-9). The site map in the report indicated that MW-8
abandoned, and MW-9 was damaged. But MW-7 could not be in the map. Where is MW-
7? Has it been abandoned?

MW-7 and MW-9 need to be located. If they could be used for monitoring, they need to be
abandoned.

ASWs and VEWs need to be added to the permit if system will reactivate. I have not
received system evaluation report if it can operate.

Thank you.

Gene Mao
Hydrogeologist
Public Health

Guilford County Government
400 West Market Street, Greensboro, NC 27401
336-641-3589 | m: 336-451-7638 | f: 336-641-4812
[e-mail] | www.guilfordcountync.gov