NC0037834_Speculative Limits_19910321

NPDES DOCUMENT SCANNING COVER SHEET
NC0037834
Archie Elledge WWTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Instream Assessment (67b)
Speculative Limits`
Environmental Assessment (EA)
Document Date:
March 21, 1991
This document is printed on reuose paper - ignore any
content on the'New-ex-me side

State of North Carolina
Department of Environment, Health, and Natural Resources
Division of Environmental Management
512 North Salisbury Street • Raleigh, North Carolina 27611
James G. Marlin, Governor George T. Everett, Ph.D.
William W. Cobey, jr., Secretary March 21, 1991 Director
Mr. Lee Byerly
Archie Elledge WWTP Superintendent
City of Winston-Salem
P.O. Box 2511
Winston-Salem, NC 27102
Subject: Proposed Limits for Archie Elledge WWTP NPDES Renewal
NPDES No. NC0037834
Salem Creek (030704)
Forsyth County
Dear Mr. Byerly:
I am writing in response to your letter of March 1 in which
you had some questions regarding the proposed limits which may be
included in your upcoming NPDES permit renewal. s have addressed
each of the items as follows:
BODS Limit
The Division of Environmental Management (DEM) normally
assigns BOD limits in terms of BOD5. The water quality models that
are used to determine NPDES permit limits are run using CBODu con-
centrations. However, CBODu is not a good compliance parameter
since the tests must be run for so long. Therefore, DEM uses long
term BOD tests in which initial and periodic nitrogen series (e.g.
TKN, NH3-N, NOx) are measured. This allows us to determine the
BODu and the NBOD (usually determined by 4.5*(final NOx - initial
NOx)). The CBODu can then be calculated by subtracting the NBOD
from the BODu. The ratio of CBODu to BOD5 (measured during the
test) is then used to obtain an NPDES limit for BOD5.
DEM will occasionally issue NPDES permits with CBOD5 limits.
However, the facility must submit GODS and CBOD5 concentrations
taken from split samples. If you submit the results from
samples with your permit application, my staff will develop your
limit in terms of CBOD5 as well.
Ammonia Limit
Pollution Prevention Pays
P.O. Box 27687, Raleigh, North Carolina 27611-7687 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

The summer ammonia limit is based on the results of the mode-
ling analysis. Based on the modeling, the winter limit may have
been able to be higher, but it is Division procedure not to have
winter limits be more than twice summer limits. In addition, the 4
mg/1 winter ammonia limit will help protect the stream from ammonia
toxicity.
Toxics Limits
Winston-Salem may request in writing to monitor for chemical
specific toxicants daily. A weekly average limit equivalent to the
limits provided in my letter of July 25, 1990 for protection to the
chronic no effect level would apply for compliance purposes, along
with a daily maximum concentration that at a minimum protects the
acute no effect level instream. For the purpose of determining the
weekly average, daily values shown towbe less than detection will
be considered equal to zero. Based upon these criteria, your
revised metals limits would be as follows:
Wkly Avg Daily Max
Parameter (ug/1) (ug/1)
Cadmium 2.6 10.4
Chromium 66 264
Nickel 116 464
Lead 33 45
Cyanide 6.6 26
This method allows more flexibility in evaluating compliance while
ensuring protection of the State's water quality standards. Should
the City choose this alternative, the monitoring frequency would
then remain fixed as daily for the duration of the permit.
The cadmium limit is needed to protect the State's water
quality standard of 2 ug/i during low flow conditions. If the City
believes that it will not be able to meet the cadmium limit with
the above daily maximum limits, a one year compliance schedule may
be written into the permit.
An effluent limit for cyanide has been proposed since our
pretreatment information indicates that 0.971 pounds per day have
been permitted. The predicted effluent concentration for this
loading is 2.7 ug/1 assuming a removal efficiency of 59%. It is
division practice to assign an effluent limit if the predicted
effluent concentration is within 1/10 of the allowable concentra-
tion.
Fecal Coliform/Disinfection
DEM understands that disinfection methods other than chlorine
may not be viable for some WWTPs depending on the nature of the
wastewater. However, any WWTP should be able to dechlorinate its
wastewater prior to discharge. Some dechlorination chemicals may
affect the results of toxicity screens. If the City plans on dech-
lorinating its effluent and informs DEM of the specific chemical it

plans on using, DEM will provide information on how that chemical
may affect bioassay results.
Augmentation of Salem Creek Flow
The City may augment the flow to Salem Creek, but would have
to guarantee a minimum flow and maintain a continuous gaging sta-
tion upstream of the outfall in order to show compliance with the
flow agreement. The QUAL2E model was not very sensitive to the
upstream flow, and the only change in BOD/NH3-N limits would be
summer/winter ammonia limits of 3/6 mg/1 at an upstream flow of 20
cfs (i.e. augment flow 5 cfs). No change in BOD or ammonia limits
would occur for a 3 cfs increase in stream flow.
Slight changes would also be made to your chemical specific
toxics limits as well as the whole effluent toxicity limit. For
your information, I have listed the l'rriits for the existing stream
flow (15 cfs) as well as stream flows of 18 and 20 cfs. You should
note that the limits given are daily maximum assuming one sample
collected per week. If the City decides to augment the flow to
Salem Creek, the City may opt to sample for toxics daily and'
receive corresponding daily maximum and weekly average limits as
explained above.
15 cfs 18 cfs 20 cfs
Cadmium (ug/ 1) : 2.6 2.8 2.9
Chromium (ug/1) : 66 69 72
Copper (ug/1): Monitor Monitor Monitor
Nickel (ug/1) : 116 122 126
Lead (ug/1) : 33 35 36
Zinc (ug/1): Monitor Monitor Monitor
Cyanide (ug/ 1) : 6.6 6.9 7.1
IWC (%) 76 72 70
The IWC is the instream waste concentration, and the chronic
quarterly toxicity test must be performed at an effluent concen-
tration equal to the IWC.
Permit Period
You also raised questions concerning the permit renewal
period. DEM is beginning to implement basinwide water quality man-
agement, and all NPDES permits are scheduled to come up for renewal
during the same year. The Yadkin River Basin permits will be exa-
mined during 1998 and 1999. Since the Environmental Protection
Agency (EPA) does not allow states to issue permits for longer than
a five year period, DEM is issuing short term permits in order to
place a given facility on the correct five year permit cycle.
Therefore, the Archie Elledge permit will expire in July 1993 and
then be issued a five year permit which will expire in July 1998.
You should note that the basin permitting schedule should be
beneficial to the regulated community once it is in place. DEM
will be developing basin management plans for each major river

basin and sending them to public notice approximately one year
prior to the permit renewal period scheduled for that basin. Thus,
the Yadkin River management plan should be completed by 1997. The
plan will contain water quality management strategies for a given
basin/subbasin which will include long term permitting strategies.
Municipalities should be able to plan for long term wastewater
treatment accordingly.
If you have any questions or comments concerning any of this
information, please do not hesitate to contact Ruth Swanek or me at
[phone].
Sincerely,
quel- C
111r-
J. Trevor Clements, Asst. Chief
cc: Steve Mauney, WSRO
Central Files

PUBLIC WORKS
DEPARTMENT
City of Winton -Salem
March 1, 1 99':
' a 0 6 1991
J. Trevor Clements, Asst. Chief
Water Quality Section
Division of Environmental Management
Post Office Box 27687
Raleigh, NC 27611-7687
Dear Mr. Clements:
The City of Winston-Salem is in the process of submitting the
appropriate documents for the renewal of Permit # NC0037834 which
expires October 31, 1991. Since this will begin the renewal pro-
cess, we have some comments and questions that we feel are war-
ranted for consideration during this process in developing the
draft permit. Many of these questions are based on your letter of
July 25, 1990 to City concerning the modeling of Salem and Muddy
Creeks.
- The BOD numbers proposed in the report are for BOD5 only,
what are the corresponding CBOD numbers? The City may be
interested in evaluating which final designations we would
prefer in the final permit document.
- The proposed Ammonia Limits have dropped drastically (Sum-
mer 3396) (Winter 5596) are these changes justified by the
modeling analysis? Especially the winter limit when stream
flows are usually higher and temperatures lower during this
period.
- The proposed toxic limits are shown as Daily max limits,
what is the basic reasoning behind not using weekly or
monthly averages? If 7Q10 flows are used to develop these
limits and daily limits are given then are not Facilities
penalized to spend millions of dollars unnecessarily to
guarantee a wide safety margin based on normal stream
flows? If daily max limits are going to be the require-
ment, then the use of Avg. Daily Flows or some percentage
flow determined between 7Q10 and Avg. Daily Flows should be
developed to be more cost effective for compliance and
stream protection.
Box 2511, Winston-Salem, North Carolina 27102

J. Trevor Clements
March 1, 1991
Page 2
- The proposed Cadmium limit of 2.6 ug/1 is very strin-
gent and will be almost impossible for the Elledge Plant to
meet due to uncontrollable sources. We could close down
all our categorical Industries and still not meet this Cad-
mium limit due to these uncontrollable sources. In
evaluating this problem pretreatment would have to be re-
quired for non categorical Industries and possibly home
owners or the expenditure of several million dollars for
metals removal and hazardous sludge handling at the plant.
These expensive and drastic alternatives are not warranted
to reduce the Cadmium concentration four to five micrograms
per liter to meet the proposed limit unless severe water
quality problems are documented.
In addition, since the detection limit for Cadmium is around
2 ug/1, will this data be accurate and reliable to determine com-
pliance?
Why is a effluent limit proposed for cyanide on our effluent?
Is the limit a total or free cyanide value? Are the metals limits
total or soluble?
- The fecal coliform limit will drop from 1000/100 ml to
200/100 ml which will require more chlorine usage to disin-
fect the effluent. Permit holders using chlorination are
required to use more chlorine to meet fecals and then re-
quired to add chemicals to remove the chlorine through
dechlorination. It appears the State is regulating indi-
rectly that all plants go to alternative disinfection
(ozone,UV) but this is not a viable or economical solution
for some plants. Will the use of dechlorination chemicals
affect Bioassay results or water quality? Is there tech-
nology available to consistently and accurately measure
the proposed chlorine residual limit at this low level?
If the City were able to augment the flow to Salem Creek 3-5
MGD during 7Q10 conditions via water from Salem Lake, what impact
would this have on the final permit limits for Elledge?

J. Trevor Clements
March 1, 1991
Page 3
The City requests by this letter that the permit renewal be
for a five year period. There have been references made that the
permit will be for three years only due to the Yadkin River Basin
Study. Since the permit will contain a reopener clause, is this
not sufficient to make changes to the permit as the Yadkin River
may or may not require? If unforeseen delays occur in the Yadkin
River Basin Study, will permits be reissued in one year time
frames? It would be in the best interest of the City and OEM to
issue a standard five year permit and then makes changes, if
needed once the Yadkin Basin Study is completed.
Please evaluate and respond to these questions and concerns
as you review our permit renewal application. Thank you for your
cooperation in this matter and if there are further questions,
please advise.
Sincerely,
Lee B'yerly
Elledge WT Plant Superintendent
pc: P. W. Swann, Asst. City Manager/Public Works
Tom Griffin, Utilities Superintendent
Barry Shearin, Utility Plants Engineer
it