NC0040797_authorization to construct_19940302

State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Environmental Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A, Preston Howard, Jr., P,E., Director
March 2, 1994
Mr. Jerry Twiggs, Director of Public Utilities
City of Hickory
P. O.Box 398
Hickory, North Carolina 28603
Dear Mr. Twiggs:
AVVA
EDl-HNR
SUBJECT: City of Hickory
Permit No. NC0040797
Authorization to Construct
Henry Fork Wastewater Treatment
Plant Expansion
Project No. CS370389-17
Catawba County
The fmal plans and specifications for the subject project have been reviewed and found
to be satisfactory.
Authorization is hereby granted for the construction of additions and modifications to
upgrade and expand the City of Hickory's Henry Fork Wastewater Treatment Plant from 6
MGD to 9 MGD to consist of a new mechanical bar screen; influent pump station
improvements, including a new electrical control building and replacement of the existing
pumps with two (2) new 5,000 GPM and two (2) 8,000 GPM variable speed pumps; a new
parallel 24-inch force main; new influent flow meters; a new grit removal chamber and grit
washer building; enlargement of the existing equalization basin to 2 MG capacity with a new
valve system for flow control; a new primary clarifier splitter box; replacement of the existing
RBCs with a dual train activated sludge treatment system designed for biological nutrient
removal, including parallel 4.5 MGD capacity basins sized for 12-hour total hydraulic
detention time, each divided into three (3) anaerobic cells with mechanical mixers, three (3)
anoxic cells with mechanical mixers, and a single aerated cell with fine bubble diffusers and
three (3) 4,690 cfrn centrifugal blowers; sludge return and recirculation pumps with sludge
return capacity of 9 MGD and recirculation capacity of 18 MGD, respectively; a secondary
clarifier splitter box; two (2) new circular clarifiers with 4.5 MGD capacity each; enlargement
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 1 0% post -consumer paper

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of the chlorine contact tank including new gas chlorine and sulfur dioxide facilities for
chlorination/dechlorination; conversion of the existing rectangular clarifiers to aerated sludge
holding/digestion tanks for primary and secondary sludge; pumps for supernatant decanting,
sludge wasting and sludge transfer to a new tank truck loading station; chemical storage and
feed facilities for alum and polymer; additions and improvements to existing odor control
facilities including relocation of an existing scrubber;additional standby generator capacity;
new process instrumentation; and all associated site work, yard piping, and electrical work.
Do not proceed with construction until the Authorization -to -Award package, EEO, and
MBE documentation/certification have been reviewed, and you are in receipt of our approval,
if funding is desired for project construction.
The Permittee shall employ an actively State certified wastewater treatment plant
operator to be in responsible charge of the wastewater treatment facilities. Such operator
must hold a valid State Certificate of the grade at least equivalent to the classification
assigned to the wastewater treatment facilities by the Certification Commission. When a new
chief operator must be obtained to be in responsible charge of the new facilities, it is required
that this be done by the time the construction of the facilities is 50% complete.
The Authorization -to -Construct is issued in accordance with Part III, Paragraph C of
NPDES Permit No. NC0040797, issued December 1, 1993 and shall be subject to revocation
unless the wastewater treatment facilities are constructed in accordance with the approved
plans, specifications, and supporting documents; and are in compliance with the conditions
and limitations specified in Permit No. NC0040797.
The Permittee shall have an acceptable sludge analysis and a sludge toxicity analysis
which have been approved by the Division of Environmental Management, Water Quality
Section prior to the disposal of any sludge from the new wastewater treatment plant. Copies
of the analyses, supporting documents, and approvals shall be submitted to the Division of
Environmental Management's Mooresville Regional Office.
The disposing, selling or free distribution of wet, dried, composted sludge or sludge -like
materials from wastewater facilities without prior review and approval by this Division is
illegal.
During the construction of the proposed additions/modifications, the permittee shall
continue to properly maintain and operate the existing wastewater treatment facilities at all
times, and in such a manner, as necessary to comply with the effluent limits specified in the
NPDES Permit.
You are reminded that it is mandatory for the project to be constructed in accordance
with the North Carolina Sedimentation Pollution Control Act, and, when applicable, the North
Carolina Dam Safety Act. In addition, the specifications must clearly state what the
contractor's responsibilities shall be in complying with these Acts.

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One (1) set of final approved plans and specifications is to be forwarded to you for
your files. The copy of the approved plans and specifications shall be maintained on file by
the Owner for the life of the project.
Upon completion of construction and prior to operation of this permitted facility, a
certification must be received from a Professional Engineer certifying that the permitted
facility has been installed in accordance with the approved plans and specifications. Mail the
Certification to the Permits and Engineering Unit, P. O. Box 29535, Raleigh, North Carolina
27626-0535. (Engineer's Certification Form is attached.)
If you have any questions or need additional information, please contact Mr. Bill
Hoffman, at [phone], extension 615.
Sincerely,
L.A. Preston Howard, Jr., P.E.
Attachment
RPT:vk
cc: HDR Engineering
Mr. Don Safrit
Mooresville Regional Office
Mr. Tom Fahnestock
Mr. Don Evans
Ms. Valerie Lancaster
Mr. Robert Teulings
Ms. Cindy Finan
DMU
SRF