WQ0035706_SOC (Amendment)_20200423

Currituck County
Eric T. Weatherly, P.E. 153 Courthouse Road, Suite 302
County Engineer Currituck, North Carolina 27929
252-232-6035
FAX [phone]
[e-mail]
MEMORANDUM
Date: April 23, 2020
To: Mr. Robert Tankard
From: Dave Robertson, Assistant Area Manager, Envirolink, Inc.
Eric T. Weatherly, County Engineer, Currituck County
RE: SOC Quarterly Report for the period ending in March 31, 2020
Moyock Regional WWTP Permit WQ0035706 SOC Update
The format will be, to use previous relevant report bullet points as a baseline, and to expand on those
issues, or eliminate them as satisfied. The latest status, in blue type, is an update on the previous report,
or other issues occurring during this quarter.
• All piping and plumbing has been upgrade to reflect the upgrades agreed upon by all parties.
o Four new RAS/WAS pumps were installed and piped to the first aeration basin in each
train.
o A Shp Homa pump was installed on top of the spray field dosing tank to use as a
backwash for the sand filters, instead of using the water in the filter dosing tank.
o Chemical feed for the Sodium Bicarbonate was moved to the first aeration tank on each
train instead of the EQ basins.
o The recycle lines are on stand-alone Shp Homa pumps and pump to the pre -anoxic tank
on each train.
o The influent force main has been piped to utilize the 2 mm Rotary Drum screen before
flowing into the existing 5 mm bar screen. The Rotary Drum screen has been put into
operation. Screenings removed to dumpster.
o Influent 5mm TSS 487mg/I. Influent 2mm TSS 397mg/I.
o EQtank. All contents removed and tank cleaned of fibrous paper products.
o The root cause of the fibers is still being investigated by Currituck County
• Aqua cell media has been returned to each aeration basin. The media is being loaded per
manufacture recommendations to achieve the effluent requirements. The media is being loaded
periodically so that the basins can be monitored for overflowing.
• Reinstalled Effluent flow meters are operational and power outlets were repaired during the
upgrades to the Regional Plant.

Added/Replaced media in granular media filters.
o Media was removed and replaced during the upgrades. The correct media and correct
amount was replaced. The filters are being backwashed daily to avoid compaction of the
media and keep optimal filtration.
o Train A rehab.
o Pre -anoxic tank through the clarifier, all contents removed, and tanks cleaned of fibrous
material. Aqua cell media reinstalled to engineered specifications.
o Aeration diffusers removed, cleaned and replaced. Tank screens removed, pressure
washed and replaced.
o At the point the influent enters the nitrification chamber/ post anoxic tank, a sanitary
Tee and 8 ft pipe have been installed between de -nitrification chamber and post anoxic
to eliminate short circuiting and to ensure proper mixing and detention time as per
original engineered drawings
o Mechanical
o A new blower was placed onsite to assist the already operational blower. This will act as
a backup or give the option to cycle each blower in sequence.
o New blower has been installed and will act as a back-up until a new VFD has been
installed. Once installed the blowers will be able to be cycled and controlled to maintain
proper D.O. through -out the plant.
o A SCADA system was installed on the plant to give the county and operations the
opportunity to respond to alarms for high water levels in the basins, power outages, and
pump failures. This can also be accessed remotely via mobile phone or laptop computer.
o New chemical pumps were installed to give the operator better control of the chemicals
being added to achieve compliance
o Spray Field
o The spray field had about 18 inches of compacted sand removed to stop the ponding
issues and help with filtration.
o A staff gauge was installed to ensure the two foot of freeboard is continuously
monitored and recorded.
o Mobile Plant
o A 60,000 gpd mobile plant was put into place and online October 2nd, 2019.
o The mobile received all influent flow until January 2nd 2020.
o A meeting was held with the WaRO on January 15, 2020 to discuss modifications to the
Regional plant and to bring the plant back on line. It was decided to run influent
through the Regional Plant and then through the mobile plant to assure continued
parameter compliance. Envirolink is in the process of preparing a piping plan illustrating
a piping connection just prior to entering the clarifiers of the Regional Plant to the
mobile plant. This will allow monitoring the Regional plant effluent quality until it is in
compliance yet running it through the mobile plant to assure the effluent to the spray
fields is in compliance.
o Mobile Plant is receiving 50% of the flow coming to the site while Train A is taken off
line, returned to engineer's specification, and then returned to service. This is
accomplished by opening the valve from the EQ tank to the Mobile plant.
o The mobile plant was put online sometime in January. The last samples taken at the end
of March were mostly compliant with exception of BOD and Fecal coliform. These

samples were taken prior to train A of the regional plant being taken off-line for its
rehab. This should give us a base line moving forward with the Rehab. The long term
goals of the mobile plant is to eventually take it out of operation once the Regional
plants effluent is in compliance.