NC0068365_Staff Report_19940210

NPDES DOCUMENT SCANNING COVER SHEET
NC0068365
Pilot Mountain WTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Staff Report
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Permit
History
Document Date:
February 10, 1994
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cc:
Permits and Engineering
Technical Support Branch
County Health Dept.
Central Files
WSRO
SOC PRIORITY PROJECT: Yes No X
If Yes, SOC No.
To: Permits and Engineering Unit
Water Quality Section
Attention: (Susan Wilson)
Date: February 10, 1994
1 o r�S
NPDES STAFF REPORT AND RECOMMENDATION
County Surry
Permit No. NC0068365
PART I - GENERAL INFORMATION,
1. Facility and Address: Pilot Mountain Water Treatment Plant
P.O. Drawer AA
Pilot Mountain, NC 27041
2. Date of Investigation: February 8, 1994
3. Report Prepared by: Lee G. Spencer
4. Persons Contacted and Telephone Number: Terry Timmons
[phone]
5. Directions to Site: From WSRO, take US 52 North to Pilot
Mtn. exit. Turn right and go to first traffic light and
turn left. Proceed 1.5 miles to Water Filtration Plant on
your right just before intersection with U.S. 52.
6. Discharge Points(s), List for all discharge points:
Latitude: 36°23'57" Longitude: 80°29'18"
U.S.G.S. Quad No. B17-NW U.S.G.S. Quad Name Pilot Mountain
7. Site size and expansion area consistent with application ?
X Yes No If No, explain:
8. Topography (relationship to flood plain included): Gently
rolling terrain. Settling lagoon could be subject to
flooding.
9. Location of nearest dwelling: One dwelling -1000' from Water
Plant.

10. Receiving stream or affected surface waters: Toms Creek
a. Classification: C
b. River Basin and Subbasin No.: 03-07-03
c. Describe receiving stream features and pertinent
downstream uses: Stream flows through very rural,
agricultural areas on its way toward the Ararat River.
Part II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of Wastewater to be permitted: N/A (Ultimate
Design Capacity)
b. What is the current permitted capacity of the Waste
Water Treatment facility? No flow limit in permit.
c. Actual treatment capacity of the current facility
(current design capacity)? It is estimated by the ORC
that between 35,000 gal. and 50,000 gal. are discharged
to the receiving stream every 2 - 3 days, from the
settling lagoon.
d. Date(s) and construction activities allowed by previous
Authorizations to Construct issued in the previous two
years: None.
e. Please provide a description of existing or
substantially constructed wastewater treatment
facilities: Sandfilter backwash water is drained to the
1/4 acre lagoon and allowed to settle. Influent
enters on one end of the lagoon and exits on the other
end via an outlet structure with sluice valved pipes at
three different levels.
f. Please provide a description of proposed wastewater
treatment facilities: N/A
g•
Possible toxic impacts to surface waters: Sandfilter
backwash water has been treated with chlorine and
aluminum sulfate (alum).
h. Pretreatment Program (POTWs only): N\A
2. Residuals handling and utilization/disposal scheme: The
lagoon is drained and cleaned approximately one time per
year. Alum type sludge is removed and spread onto a level
field which is adjacent to the plant, in order for it to dry
out so it can be hauled. It is then taken to the Surry
County landfill.
NPDES Permit Staff Report
Version 10/92
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3. Treatment plant classification (attach completed rating
sheet): Class I
4. SIC Code(s): 4941
Primary 21 Secondary
Main Treatment Unit Code: 5 0 0 1
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant
Funds or are any public monies involved. (municipals only)?
2. Special monitoring or limitations (including toxicity)
requests: None
3. Important SOC, JOC or Compliance Schedule dates: None
4. Alternative Analysis Evaluation: Has the facility evaluated
all of the non -discharge options available. Please provide
regional perspective for each option evaluated.
Spray Irrigation:. Impractical
Connection to Regional Sewer System: Impractical
Subsurface: N/A
Other disposal options: Supernatant from lagoon used to be
recycled back through the Water Plant. Now, due to concerns
over the possible formation of THMs, this practice has been
discontinued.
5. Other Special Items:
PART IV - EVALUATION AND RECOMMENDATIONS
This office has no objection to the reissuance of this
permit. The facility appears reasonably well operated and
maintained. It was pointed out to the ORC that only the upper
discharge valve should be open, and that alum sludge levels must
be kept well below this discharge level.
Signature of report preparer
Water Quality RegiOhal Supervisor
NPDES Permit Staff Report
Version 10/92
Z -io - 94-
Date
Date
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