NC0072664_Regional Office Historical File Pre 2018 (147)

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Q MichZ . Easley
Governor
j r William G. Ross, Jr.,Secretary
—I North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P.E., Director
Division of Water Quality
February 7, 2003
Mr. Mark Hawes, P.E.
Director of Environment and Safety
Shurtape Technologies, Inc.
P.O. Box 1530
Hickory, North Carolina 28603-1530
Subject: Technical Assistance Visit
Stony Point Wastewater Treatment Plant
1976 Model WWTP
NPDES Permit No. NCO072664
Alexander County, North Carolina
Dear Mr. Hawes:
A return technical assistance visit was conducted by Sonja Williams of the Mooresville
Regional Office (MRO). and Roger Edwards of the Asheville Regional Office (ARO) at Stony
Point Wastewater Treatment Plant (WWTP) on December 10, 2002, at your request. Travis
Brannon, ORC; Ray Pope, Back-up ORC; Wayne Roberts, Resource Coordinator and you were
present to represent the facility. The primary focus of the visit was to review operations,
maintenance and process control activities with the WWTP staff. The following suggestions are
based on the observations obtained at the time of the visit:
1. Influent Characteristics: pH 7.5, Temp 12.1 C, bar screen, normal appearance.
2. Aeration Basin Characteristics: Dissolved Oxygen (DO) 2.4 mg/L —reading taken when
blowers off at 40 minute mark. Medium neoprene diffuser heads, One 5 hp blower,
cycled 1 hour 15 minutes off / 15 minutes on. Blower belts satisfactory condition.
Recommendations: It is suggested to 1) Move the blowers off of the plant for ease of
maintenance and to keep the clarifier from vibrating when the blowers cycle on. 2)
Adjust the operating time on the blower by watching the DO meter for an entire cycle. Do
not allow DO to drop below 0.5 mg/L for 30 minutes. Also monitor effluent DO (maintain
above 5. 0 permit limit). 3) Tape DO cord at 3 feet and 6 feet for DO profile for
consistency between operators. 4) Keep a maintenance log for blowers, filters, diffusers,
and other maintenance issues. 5) Clean diffusers twice per year as preventive
maintenance.
3. Clarifier Characteristics: pH 6.8, Alkalinity 120 mg/L, Total residual chlorine 0.00
mg/L, 10 feet clarifier depth, Slight oil film on clarifier surface, One.3 hp return'(RAS)
blower, cycled 1 hour 15 minutes off / 20 minutes on. Blower belt cracked, no air filter
present.
CusNCDENRvice
1 800 623-7748
Mooresville Regional Office, 919 North Main Street, Mooresville, NC 28115 PHONE [phone]
FAX [phone]

Shurtape — Stony Point WWTP
Technical Assistance Visit
Page 2
Recommendations: It is suggested to 1) Install air filter to blower. 2) Replace blower
belt. 3) Reduce RAS rate- do not exceed 3 feet sludge in clarifier from cone. 4) Extend
clarifier baffle board above water line to keep floatable materials confined for easier
removal by the operator. 5) Install ball valve for better control over RAS rate.
4. Chlorine Contact Characteristics: Tablet chlorinator, facility is using Plant Pro chlorine
tablets 68% Calcium Hypochlorite.
Recommendation: 1) Periodically take a sludge depth in the chlorine contact chamber.
Sludge depth should be maintained at < 1.0 foot. 2) Try placing nylon mesh over
individual chlorine tablet tubes to help prevent tablets from dissolving quickly.
5. Effluent Characteristics: pH 7.25, Temperature 10.8 C, DO 9.3 mg/L, Total residual
chlorine 1.89 mg/L.
Recommendations: It is suggested to 1) Add, as needed, sodium bicarbonate to restroom
toilet that is closest to plant for pH and Alkalinity adjustment. 2) Decrease chlorine
usage below 1.0 mg/L. Chlorine levels should be maintained to provide proper
disinfection in order to comply with fecal coliform permit limits.
The observations above are those most apparent from the visit. I hope these suggestions will help
you in operating the wastewater treatment plant. Please advise of questions or comments to
either Roger Edwards [phone] or me [phone].
Sincerely, 4'�,f,,,
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Sonja/ Williams
WWTP Consultant
Mooresville Regional Office
cc: CMRO
Central Files
Roger Edwards, Technical Assistance & Certification Unit (ARO)