NC0088749_Correspondence_20210208

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH NORTH CAROLINA
Director Environmental Quality
February 8, 2021
Crystal Messik
L & N Wastewater Management
5646 Hampton Road
Clemmons, NC 27012
Subject: Technical Assistance Visit
Lissara Wastewater Treatment Plant
NPDES Permit NC0088749
Forsyth County
Dear Mrs. Messik,
On Wednesday, January 20, 2021, I met with you and Jason Messik for a Technical
Assistance visit at the Lissara Wastewater Treatment Plant located in Forsyth County. The
visit was at your request concerning some higher -than -normal effluent BOD results in 2020
causing the WWTP to violate the NPDES permit limits. My observations and highlights of our
conversation are listed below for your review.
Although nothing conclusive was found to be the cause of BOD problems, the following
remedial actions were discussed:
• Installing throttle valves on the influent pumps or increasing the influent
recirculation rate to reduce the influent flow going through the aeration basin and
increase the detention time in the aeration basin.
• Collecting a BOD sample prior to dechlorination to rule out the possibility of the
dechlorination tablets interfering with the BOD results.
Check the dissolved oxygen level in the aeration basin. A dissolved oxygen
concentration of 2 to 3 mg/I is usually sufficient for carbonaceous oxidation.
• Since the plant is extremely underloaded for its design flow, try removing two of the
chlorination and dechlorination tubes, while closely monitoring the final effluent Cl2
residual.
• A settleometer would work better than Imhoff Cones (used for settleable solids test)
in determining the sludge settleability.
D_E
DORTH CAROLINA
epartment[ emeonmentai WeeV�
North Carolina Department of Environmental Quality I Division of Water Resources
Winston-Salem Regional Office 1450 West Hanes Mill Road, Suite 300 I Winston-Salem, North Carolina 27105
336.776.9800

• Start monitoring the mixed liquor suspended solids (MLSS) concentration in the
aeration basin on a regular basis. When the plant appears to be producing the
highest quality effluent, develop a sludge wasting program to keep the MLSS at this
target goal. The MLSS concentration can be used along with the 30-minute
settleometer test to determine the sludge volume index (SVI), another process
control tool.
Our office appreciates the effort that L & N Wastewater Management staff puts into staying
in compliance with your NPDES permit by reaching out to the Winston-Salem Regional Office
for technical assistance.
In closing I would like to thank you for the opportunity to visit the Lissara Wastewater
Treatment Plant and try to help you with your plant problems. It was a pleasure getting to
work with you both and tour the plant. If I can be of any more help, please do not hesitate to
contact me at [e-mail] or (336) 776 - 9694.
Sincerely, fvu
Ida&
Gary Hudson
Water Quality Regional Operations
Division of Water Resources
cc: Laserfiche