NC0029980_correspondence_20030910

AlcovvIt
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
WATER QUALITY SECTION
FAX# [phone]
FAX TO:
FAX #
PHONE #
Madolyn Dominy, EPA Reg 4
404-562-8692
FROM:
FAX#
PHONE #
Tom Belnick, NPDES Unit
919-733-0719
919-733-5083, ext 543
DATE:
SUBJECT:
# PAGES
(including cover)
9/10/2003
Miller Brewing/ TRC Implementation
4
COMMENTS:
Madolyn- I'm faxing a copy of our NPDES Implementation
Strategy for TRC, which was prepared by Susan Wilson. The
permitting for Miller Brewing was consistent with this strategy.
The implementation strategy prepared by Susan Wilson states that
NPDES will implement TRC limits according to our basinwide
permitting schedule, beginning with the Neuse River basin
renewals. Because the Miller Brewing permit was held up for so
long, the final issuance did not occur until after April 1, 2003.
However, we don't think it fair (or consistent) for them to be the
only permittee in the Roanoke River Basin to get TRC limits now,
while we won't implement it for the remaining Roanoke River
Basin permittees until next permit cycle.

NPDES Implementation of Triennial Review Changes
Every three years the State is required by the Clean Water Act to review its surface
water quality standards and classifications to determine if changes are needed and, if
necessary, to make those changes. The Clean Water Act also requires the review of any
existing variances to surface water quality standards every three years. This review
process is referred to as the "triennial review." Public hearings were held to solicit
comments for the 2000-2003 Triennial Review of surface water quality standards
during the summer of 2002. The hearing officer's recommendations were presented
before the state's Environmental Management Commission on October 10, 2002.
The hearing officer's proposed changes to the existing standards included modifications
to the arsenic, cyanide, methylene blue active substances (MBAS), and total residual
chlorine (TRC) standards, and the addition of a methyl tert-butyl ether (MTBE)
standard. All of the hearing officer's changes were adopted with the exception of
MTBE. The proposed changes will become effective April 1, 2003 (this is the soonest
time that the rule may become effective - pending approval by the Rules Review
Commission). The changes, and their impact to NPDES permitting, are discussed
below. For an explanation of calculating allowable levels (to implement in permits)
based on the type of standard, please refer to the Appendix of this document.
Arsenic
The current arsenic standard is based on aquatic life protection and is set at 50 ug/1 for
fresh and salt waters.
With the Triennial Review, a human health standard and water supply standard of 10
ug/1 were adopted by the EMC (in addition to the aquatic life standard).
Aquatic Life Standard - 50 ug/1
Human Health Standard - 10 ug/1
Water Supply Standard - 10 ug/1
Because the standard will be officially adopted April 2003, you should begin
implementation of this standard with renewal of the Neuse permits. As with all limits, if
the permittee requests a compliance schedule, with a reasonable explanation as to why
the schedule is needed, you may wish to grant a compliance schedule not to exceed 2
years.
Total Residual Chlorine
Prior to this Triennial review, total residual chlorine was an Action Level Standard,
except in designated Trout waters. As such, the NPDES Unit only implemented a
chlorine limit for facilities that had an existing chlorine limit, for facilities that were
new, or for facilities that were expanding their design flow.
With the Triennial Review, the total residual chlorine Action Level Standard has been
modified to an Aquatic Life Standard of 17 ug/1 (not just an Action Level Standard).
The Aquatic Life Standard will remain for designated Trout waters.
Aquatic Life Standard - 17 ug/1 (freshwater only)
Trout Waters - 17 ug/1
Triennial Review Implementation
2003

Because the standard will be officially adopted April 2003, you should begin
implementation of this standard with renewal of the Neuse permits. However, because
a facility likely will need to add dechlorination (or use another means of disinfection) to
meet the standard, a compliance schedule of 18 months from the effective date of the
permit will be allowed in order for the facility to budget, design, and construct the
additional treatment unit. The NPDES Unit has promulgated minimum design criteria
in order to expedite permitting of dechlorination units.
To reiterate, all facilities that use chlorination or have chlorine as a parameter of
concern, should incorporate a chlorine limit in the permit based on the Aquatic Life
Standard of 17 ug/1. This includes water treatment plant systems.
Cyanide
North Carolina water quality regulations currently designate Cyanide as having an
Aquatic Life Standard of 5 ug/l.
The Triennial review did not change this standard, however, the rules have been
modified to state that a discharger would be allowed the option of developing a site -
specific standard based upon the aquatic life at the site in accordance with EPA
procedures.
For implementation purposes, should a facility request the site specific standard, the
NPDES Unit should allow this. However, the facility should be given a timeline to
complete the site -specific standard. [You should consult with the Classification and
Standards Unit, as well as the NPDES supervisor prior to approval)
Aquatic Life Standard - 5 ug/1 (Freshwater), 1.0 ug/1 (Saltwater)
Site specific standard - Facility may opt to perform a site specific standard
MBAS (Methylene Blue Active substances)
Prior to this Triennial review, MBAS had an Aquatic Life Standard of 500 ug/1. The
Triennial review changed this Aquatic Life standard to an aesthetic standard of 500
ug/1 to be applied in designated Water Supply waters only.
Water Supply standard - 500 ug/1 (aesthetic standard only)
Because the standard will be officially adopted April 2003, you should begin
implementation of this standard with renewal of the Neuse permits. It is not likely that
a facility will need a compliance schedule for this limit. Because this is an aesthetic
standard, dilution will be calculated using a 30Q2 flow, not the 7Q10 statistic.
Other information contained in the Triennial Review (that does not pertain to specific
standards):
• Comments regarding water quality and thermal variances will be forwarded to the
NPDES Unit for further review and consideration at the time of the next scheduled
renewal of these variances.
Triennial Review Implementation
2003

Viments
concerning the implementation of nutrient criteria and the
ablishment of new (E. coli) bacteriological criteria will be forwarded to the
ropriate individuals for further review and consideration at the time these
eria are developed.
SAW
030825
Appendix
Aquatic Life Standard. In general, aquatic life standards were developed to protect
aquatic life from chronic toxicity. Implementation of aquatic life standards are based on
7Q 10s of the receiving stream. To calculate the allowable level using an aquatic life
standard, use the following equation:
WLAtoxicant = ((Cinstream * (Qeff * 1.55 + Qup))-QupCup) / Qeff* 1.55
Where,
WI
Atoxicant = allowable level (permit limit)
Cinstream = water quality standard
Qeff = effluent flow, MGD (permitted monthly average flow)
Qup = 7Q10s, cfs
Cup = upstream toxicant concentration (review ambient station data or assume 0 ug/1)
Water Supply Standard. Standards listed under Water Supply are applicable in
classified Water Supply (WS) waters. These standards were derived to protect human
health through the consumption of water.
If the toxicant is a non -carcinogen, the 7Q10s may be used in the equation as the
upstream flow (Qup).
If the toxicant is a carcinogen, average stream flow (Qavg) should be used as Qup in the
equation given above.
Aesthetic Quality standards. If the toxicant is based on aesthetic quality, the 30Q2
should be used as Qup. Aesthetic quality standards protect for taste and odor as well
as general aesthetic value.
Human Health Standard. Standards listed under Human Health are applicable to all
waters. These standards are derived to protect human health through the consumption
of water, fish, and shellfish. To derive the permit limit, the design flow is similar to
those listed for WS waters.
If the toxicant is a non -carcinogen, the 7Q 10s may be used in the equation as the
upstream flow (Qup).
If the toxicant is a carcinogen, average stream flow (Qavg) should be used as Qup in the
equation given above.
Triennial Review Implementation
2003