WQ0039473_Correspondence_20190423

Soil, Water, & Environment Group, PLLC
.3216 Layers Drive, Suite B
Raleigh, NC 27607
Ph# [phone] • Faxr {919) 899-9100 - htipalwnlv.swegrp.com
Soil, Water, & Environment —
Group
April 23, 2019
Mr. Tom McKinney
Department of Environmental Quality
Division of Water Resources
Non -Discharge Permitting Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Re: WQ0039473, Atkinson Milling Company WWTF Wastewater Irrigation System
Johnston County
Dear Mr. McKinney,
Please find enclosed our official updated notificaiton to DEQ regarding Permit No WQ0039473,
Atkinson Milling Company WWTF, Wastewater Irrigation System, Johnston County, NC.
1. Wastewater parameters (pH, BOD and TSS):
As we have reported, the laboratory analysis of the wastewater taken November 28, 2018
showed both BOD and TSS were out of compliance with the permit conditions. The wastewater
sample taken on April 2, 2019 shows progress in bringing the parameters into compliance.
Through the addition of magnesium hydroxide and/or calcium hydroxide, the pH appears to be
settling out around 6.0, up from the pH of 4.4 noted in December 2018. This indicates good
progress with pH adjustments. TSS is down from 138 ppm in December to 83 ppm in the last
sample. Not unexpectedly, considering that the anaerobic upflow reactors have not been re-
seeded, the BOD has not exhibited any significant reduction, from a level of 2580 ppm in
December down to 2330 ppm.
2. Structural Compromise of the Settling Tank:
The compromised settling tank has been removed from the system as of December 21, 2018.
There was no visually apparent evidence of leakage when the tank was removed. No further
structural modifications to the system should be necessary.

3. Progress in the Corrective Action Plan:
The proposed corrective action plan was to replace the plastic settling tank with a reinforced
concrete tank. The reinforced concrete tank was placed on December 21, 2018. The concrete
tank appears to be functioning properly at this time. Over the period since the last update, the
switch of the hushpuppy production line to the "new" unit has been completed. As was
expected, there has been a corresponding drop in the overall wastewater production in the
system due to the improved production process. At this time, the flows have been averaging in
the range of 6,000 gallons per week, down from approximately 10,000 gallons per week
previously. Flow reduction obviously is a benefit, as it provides additional storage time in the
system for pollutant attenuation and reduces the effective hydraulic and process load onto the
land application area.
As noted previously, we are continuing to evaluate pH stabilization measures. Ideally, a pH
between 6.5 and 7.0 is preferred, but the anaerobic decomposition should be acceptable at a
pH in excess of 6.0. The initial use of calcium hydroxide has been hampered by the apparent
need for aggressive agitation, which is mostly available in the latter portions of the system.
Ideally, we want to be able to adjust pH from an initial point in the system, such as the floor
drain in the processing area. The addition of magnesium hydroxide shows some promise and
benefits over the calcium hydroxide in this case, including ease of handling, introduction at a
more advantageous point, and possibly a flocculation effect that could improve the effectiveness
of the settling tank and solids recovery components. There is apparently some additional
flocculation effect present, as the TSS has been reduced by approximately 40%.
At the point the pH is stabilized, it is proposed that the reactors be "spiked" with material from
another treatment works to "jump start" the bacteria population's recovery in the reactor cell. It
would be counterproductive to spike the reactor, merely to re -introduce low pH material that
detrimentally affects the bacteria population. We are continuing to monitor the progress of the
pH regulation within the system. We anticipate once the anaerobic upflow reactors have a re-
introduced and stable bacteria population, we will see much better results on BOD reduction. At
this point, the relatively small reduction (approximately 10%) is probably attributable to the
overall reduction in solid materials as opposed to any improvement in biological treatment. We
have identified a good potential source for suitable, biologically active "spike" material in the
near vicinity, and will keep you informed as to progress.
Because both the pH attenuation chemicals currently under evaluation contain either calcium or
magnesium, we also propose to recalculate the Sodium Adsorption Ratio (SAR). Either
chemical is required in fairly moderate amounts, so no ill effect to the land application area is
anticipated, but verification by analysis is needed.

We appreciate your assistance in this matter. We have replaced the structurally compromised
components and actively working to bring the chemical and biological treatment components of
the system back into compliance. We look forward to any comments you have on the progress
of the corrective action plan and remediation as related to the permit for the Atkinson Milling
Facility. Thank you.
Sincerely,
A.R. Rubin, PhD
Stephen L. Crawford, PE
Scott J. Frederick, NCLSS, El
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Soil, Water, & Environment
Group
Enclosures: nla