NCG500618_Staff Report_20070924

SOC PRIORITY PROJECT: No
To: NPDES Stormwater and General Permits Unit
Water Quality Section
Attention: Charles Weaver
Date: September 24, 2007
NPDES STAFF REPORT AND RECOMMENDATI
County: Iredell
NPDES Permit No.: NCG500618
PART I - GENERAL INFORMATION
1. Facility and address: Mack Molding Company
149 Water Plant Road
Statesville, NC 28144
ECEOWE
SEP 2 7 2007
OENR - WATER QUALITY
POINT SOURCE BRANCH
2. Date of investigation: September 12, 2007
3. Report prepared by: Samar Bou-Ghazale, Environmental Engineer I
4. Person contacted and telephone number: Frank Bumgarner, [phone]
5. Directions to site: From the jct. of Old Mountain Road (SR 1005) and I-40 west of
Statesville, travel southeast on Old Mountain Rd. 50 yards and turn onto Water Tank
Road. The Mack Molding Company is located at the end of Water Tank Rd.
6. Discharge point(s), List for all discharge points: -
Latitude: 35° 46' 15"
Longitude: 80° 59' 58"
Attach a USGS Map Extract and indicate treatment plant site and discharge point on map.
USGS Quad No.: D 15 SW
7. Site size and expansion area consistent with application: Yes.
8. Topography (relationship to flood plain included): Gently rolling, 2- 4% slopes. The site
is well removed from any flood plain.
9. Location of nearest dwelling: Approx. 500+ feet from the manufacturing site.

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10. Receiving stream or affected surface waters: U. T. To Broad Meadow Creek
a. Classification: WS-IV
b. River Basin and Subbasin No.: Catawba 030832
c. Describe receiving stream features and pertinent downstream uses: The receiving
stream is actually several hundred feet south of the plant site. Under normal
conditions, it is unlikely that the effluent will reach the UT, except during periods
of wet weather. The area is generally rural with agriculture being the primary use.
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of wastewater: 500 gpd (Design Capacity)
b. What is the current permitted capacity: N/A
c. Actual treatment capacity of current facility (current design capacity): 1000 gpd
d. Date(s) and construction activities allowed by previous ATCs issued in the
previous two years: N/A
e. Description of existing or substantially constructed WWT facilities: There are no
existing WWT facilities. The discharge consists of cooling tower blowdown.
f. Description of proposed WWT facilities: There are no proposed WWT facilities.
g.
Possible toxic impacts to surface waters: Toxic impacts are not expected since it
is unlikely that the discharge will reach surface waters except during extended wet
periods. Biocidal additives are proposed for use in the cooling towers, and have
been approved for use by the Division's Aquatic Toxicology Unit.
h. Pretreatment Program (POTWs only): Not Needed.
2. Residual handling and utilization/disposal scheme: Residuals generation is not expected.
3. Treatment plant classification: Does not meet minimum criteria for a Class I rating.
4. SIC Code(s): 3780 Wastewater Code(s): 14 MTU Code(s): N/A
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant Funds or are any public monies
involved (municipals only)? No public monies were used in the construction of this
facility.
2. Special monitoring or limitations (including toxicity) requests: None at this time.
3. Important SOC/JOC or Compliance Schedule dates: N/A

Page Three
4. Alternative analysis evaluation
a. Spray Irrigation: This option may be available, however, it would be economically
impractical given the small quantity of wastewater generated.
b. Connect to regional sewer system: The nearest municipal collection system is
4.6 miles from the site.
c. Subsurface: This option may be available, however, it would be economically
impractical given the small quantity of wastewater generated.
d. Other disposal options: None that we are aware of.
PART IV - EVALUATION AND RECOMMENDATIONS
The applicant, Mack Molding Company, has applied for a GP for the discharge of up to
500 gpd of non -contact cooling water from a cooling tower. This cooling tower has been in
existence since 1989. In March 2007, Mack Molding Company obtained approval of the Aquatic
Toxicity Unit for the use of a corrosion inhibitor "Dica 66" in their water treatment system.
The discharge will be released into a storm drain at the southeast corner of the facility,
and travel for several hundred feet before discharging into the receiving stream.
It is recommended that a GP be issued as requested.
Signature of Report Pep r
7__2" /5 1/
Date
Water Quality Regional Supervisor Date