NC0085707_Permit Modification_19991123

Mate of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
November 23, 1999
Mr. William Silver
Dare County Water System
P.O. Box 578
Buxton, North Carolina 27920
1t •
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCE5
Subject: NPDES Permit Modification
NPDES Permit NCO085707
Cape Hatteras Reverse Osmosis WTP
Dare County
Dear Mr. Silver:
The Division issued the subject permit on September 20, 1999. A review of the permit file by the
Division's Point Source Compliance Enforcement Unit noted a typographical error on the Effluent
Limitations and Monitoring Requirements page. This permit modification corrects that typographical
error.
Please find enclosed the revised permit page. This page should be inserted into your permit. The
old page may then be discarded. All other terms and conditions contained in the original permit
remain unchanged and in full effect. This permit modification is issued under the requirements of
North Carolina General Statutes 143-215.1 and the Memorandum of Agreement between North
Carolina and the U. S. Environmental Protection Agency.
If any parts, measurement frequencies or sampling requirements contained in this permit
modification are unacceptable to you, you have the right to an adjudicatory hearing upon written
request within thirty (30) days following receipt of this letter. This request must be a written petition
conforming to Chapter 150B of the North Carolina General Statutes, filed with the Office of
Administrative Hearings, Post Office Drawer 27447, Raleigh, North Carolina 27611-7447. Unless such
demand is made, this decision shall be final and binding.
If you have any questions concerning these permit modifications, please contact Charles Weaver
at [phone], extension 511.
Sincerely,
/� 7W
T. Stevens
cc: Central Files
Washington Regional Office, Water Quality Section
Point Source Compliance Enforcement Unit
NPDES Unit
Aquatic To)dcology Unit
1617 Mail Service Center, Raleigh, North Carolina 27699-1617 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer VISIT US ON THE [e-mail]

Permit NCO085707
A. (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL
Upon commencement of the discharge and lasting until expiration, the Permittee is authorized to
discharge from outfall serial number 001- reverse osmosis treatment reject. Such discharges shall
be limited and monitored by the Permittee as specified below:
.... T.r.•' .::.L. "'.i::-wA' :. '... :. ..
9
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. -:::. .. dS:.: L.-.
F
rw.
.. ",lv.. Y"y ".�
w�44K
Flow
1.8 MGD
Continuous
Recording
Effluent
Total Suspended Solids
20.0 m
30.0 m L
Weekly
Grab
Effluent
Settleable Solids
0.1 ml/L
0.2 mVL
Weekly
Grab
Effluent
Turbldity2
See note 2
Weekly
Grab
Effluent
H3
See note 3
Weekly
Grab
Effluent
Arsenic
25 N
2/Month
Grab
Effluent
Beryllium
0.06
2/Month
Grab
Effluent
Cadmium
2.5 ligli
2/Month
Grab
Effluent
Chloride
Month
Grab
Effluent
Chromium
10YgA
Month
Grab
Effluent
Copper
2/Month
Grab
Effluent
Cyanide
0.5 ligA
Month
Grab
Effluent
Lead
12.5 ligA
2/Month
Grab
Effluent
Mercury
0.012 u 1
2/Month
Grab
Effluent
Nickel
4.2 jjg11
2/Month
Grab
Effluent
Salinity
2/Month
Grab
Effluent
Selenium
36 ygil
2/Month
Grab
Effluent
Silver
2/Month
Grab
Effluent
Zinc
2/Month
Grab
Effluent
Fluoride
2/Month
Grab
Effluent
Iron
2/Month
Grab
Effluent
Total Residual Chlorine4
2/Month
Grab
Effluent
Total Phos horus5
2/Month
Grab
Effluent
Acute ToxiCfty6
Quarterly
Grab
Effluent
Notes:
1 Samples shall be collected at some point after all treatment units and prior to discharge, unless
otherwise noted.
z The discharge shall not cause the turbidity of the water at the discharge point to exceed 25 NTU. If
the turbidity exceeds these levels due to natural background conditions, the discharge level cannot
cause any increase in the turbidity in the receiving water.
3 The pH shall not be less than 6.8 standard units nor greater than 8.5 standard units.
4 Total Phosphorus monitoring shall be increased to monthly if any chemicals containing phosphates
are added during the treatment process.
s Total Residual Chlorine monitoring is only required if chlorine is added.
s Acute Toxicity Limit P/F (Mysidopsis bahia) @ S00%, during the months of January, April, July, and
October. See Part I, Condition A. (2.) . Further studies will be required to determine the cause of
toxicity, if any. The collection of samples shall coincide with the sampling of other parameters.
The Permittee shall perform a study at the point of discharge as specified in Part I, Condition
A(3).
Values reported below quantitation levels shall be considered compliant with the permit.
All samples collected shall be of a representative discharge.
There shall be no discharge of floating solids or visible foam in other than trace amounts.