NC0024538_Comments_20191206

NORTH CAROLIN
Post Office Box 207•Shelby,NC 28151-0207 Shelby,t �
December 6, 2019
Mr. Gary Perlmutter RECEIVED
NCDEQ/ NPDES Complex Permitting Unit
1617 Mail Service Center DEC 13 2019
Raleigh, North Carolina 27699-1617 NCDEQ/DWR/NPDES
RE: DRAFT NPDES PERMIT NC0024538 Comments
City of Shelby, NC
Dear Mr. Perlmutter:
By the end of 2020 the City of Shelby will have invested well over $35.0 Million in upgrades to
the First Broad WWTP. These upgrades were required by NCDEQ's implementation of more
stringent limits which became effective in 2016 ($10.5M), additional influent/headworks
upgrades in 2018 ($6.6M) and currently replacement of our Biosolids Handling facility ($18M)
which is scheduled to be completed in late 2020.
Based upon previous upgrades the equipment list for the First Broad WWTP should be:
• Course manual and two fine rotary mechanical screens
• Grit Removal System
• Main Lift Liftstation with four centrifugal pumps
• External Powerhouse for Influent;
• Primary Splitter Box;
• Two (2) primary clarifiers
• Raw Sludge Pump Station
• Three Aeration Basins, each with
o One (1) Anoxic Section with three cells each.
o Four (4) Oxic Zones
• Four (4) Secondary Clarifiers
• WAS Pump Station
• One (1) Gravity Sludge Thickener
• One (1) Gravity Sludge Pump Building
• One (1) two-compartment contact for chlorine disinfection and sulfur dioxide for
dechlorination
www.cityofshelby.com

• Sludge Holding Tank
• Two (2) belt filter presses
• Ten (10) bay sludge compost building
• 2000KW Stand-by Generator (Whole Plant) and 800KW Generator (Influent Only)
The City will be bringing on new equipment with the construction of the new biosolids handling
facility in late 2020. The new anaerobic digestion complex will come on line and then the
compost facility will be decommissioned.
With the changes, it is anticipated that the following equipment will become operational in
September 2020:
Add:
• Two Anaerobic Digesters
• One Sludge Holding Tank
• Digester Control building— Boilers and Pumps
• Dewatering Facility with Polymer Feed and Two Belt Presses
• Covered Dewatered Solids Pad
After start-up the following equipment is anticipated to be decommissioned in December 2020:
Remove:
• Two (2) belt filter presses
• Ten (10) bay sludge compost building
MISCELLANEOUS PERMIT MODIFICATION COMMENTS:
Total Silver
The draft permit that you have provided indicates that quarterly monitoring for Total Silver will
be implemented due the use of<5.0 ug/L by our contract laboratory on multiple occasions. You
have stipulated that that our PQL must be less than 1.0 ug/I. For some reason our laboratory
has shifted back and forth from PQL of 1.0ug/L to 5.0 g/L. We have brought this up to our
laboratory a couple of times.
Considering the fact that our sewer system has a pretreatment program and long term
monitoring (LTM) is required, the additional stipulation of this monitoring is not necessary. The
City will continue to monitor quarterly with the LTM and will issue a letter to our contract
laboratory indicating the correct PQL.
Mercury Minimization Plan:
Based upon the implementation of the dental amalgam rule during the permit cycle, the City of
Shelby would like to request that mercury minimization plan requirement be removed from this
www.cityofshelby.com

permit. As you alluded to in the draft permit, there were no exceedances of the Water Quality
based limitations.
1, 4- Dioxane
The draft permit alludes to the discharge of 1,4 Dioxane to the First Broad WWTP from a
groundwater remediation site at one of our local industries. The draft permit implements a
change to require monitoring for 1,4 Dioxane on a quarterly basis.
In Appendix A of this letter you will find data from this remediation site including flows and
data from periodic testing by their consultant. Based upon the low discharge flows from the
groundwater mediation activities and low discharge levels, the City would like to request that
this monitoring be added to the Effluent Pollutant Scan (Part I A.3.) which will be required
annually.
Toxicity Testing
Based on the consistent pass rates for effluent toxicity and our 17% instream waste
concentration, the City would like to request that our facility be reduced to annual monitoring
for toxicity.
If you have any questions, please don't hesitate to contact me at 704-669-6570.
Cordially,
1 A F.)/1(‘L
David W. Hux
Director of Water Resources
Cc: Mr. Rick Howell, City Manager
Brad Greene; Plant Operations Superintendent
Sibyl Brotherton, Plant Supervisor/ORC
Certified Mail 7018 0680 0001 0376 5521
www.cityofshelby.com

APPENDIX A
Honeywell International
Groundwater Remediation Discharge
Month/Year Flow 1,4 Dioxane*
gpd ppb
Jan-18 669.4
Feb-18 1,036.3
Mar-18 979.6 40
Apr-18 933.6
_ May-18 930.8
Jun-18 891.9 34.6
Jul-18 880.1
Aug-18 847.6
Sep-18 845.7 35.1
Oct-18 800
Nov-18 846.3
Dec-18 905.5 28.3
Jan-19 918.3
Feb-19 977.5
Mar-19 885 24.5
Apr-19 841.3
May-19 880.7
Jun-19 2183.2 16.7
Jul-19 2181
Aug-19 2252.9
Sep-19 1991.5 24.5
Oct-19 2032.6
Nov-19 1850.4
*Data from Hart& Hickman