NC0027286_Staff Report_19961023

cc: Permits and Engineering
Technical Support Branch
County Health Department
Central Files
WSRO
5,'V 4p7L
SOC PRIORITY PROJECT: YES NO X
To: Permits and Engineering Unit
Water Quality Section
Attention: (Mark McIntire)
AUTHORIZATION TO CONSTRUCT
NPDES PERMIT REPORT AND RECOMMENDATIONS
Date: October 23. 1996
County: Watauga
Permit No. NC: 0027286
PART I GENERAL INFORMATION
1. Facility Name and Current Address: Town of Blowing Rock
The Honorable Mr. Rufus Hallmark, Mayor
P.O. Box 47
Blowing Rock, North Carolina 28605
2. Date of most recent NPDES Staff Report: (attach copy) June 27, 1995
3. Changes since previous action on NPDES Permit: None
4. Verify Discharge Point(s) on plans with current NPDES Permit. List for all discharge
points. No change in discharge point location due to this authorization to construct.
Latitude: 36°08'32" Longitude: 81 °40' 10"
Attach a USGS map extract and indicate treatment facility site and discharge point on
map.
U.S.G.S. Quad No. C-12-NW U.S.G.S. Name Boone
5. Treatment plant classification: (attach completed rating sheet) Class III (57 Points)

PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
(PROVIDE THE FOLLOWING INFORMATION IF IT IS NOT ON THE PREVIOUS NPDES
STAFF REPORT) See previous staff report
2. Please provide a description of proposed wastewater treatment facilities: The plant will
add a sodium metabisulfite system for dechlorination. There is an existing 16" discharge
line from the package plant aeration /clarification/chlorine contact basins at the plant.
A pump station and 500 gallon tank will be installed in the building to feed the sodium
metabisulfite into the existing line from the package plant tank.
PART III - EVALUATION AND RECOMMENDATIONS
A site inspection on October 18, 1996, revealed the Town is working on managing the sludge
at the plant. The agreement has been finalized for Lenoir to accept the sludge. Two of the four
aeration basins had been previously used to store sludge. These basins had been emptied and
prepared for maintenance. Sludge storage at the plant has been adequately reduced so the plant
can operate effectively.
Recommendation is made to issue the authorization to construct. The Town of Blowing Rock
has been noncompliant with the total residual chlorine limit for some time. The post -air chamber
method of dechlorination currently in use fails to operate consistently. It appears that the
engineer has addressed the cold temperatures in this area by placing the sodium metabisulfite line
below ground to prevent freezing.
k.-Vn,07dau
Signature of report preparer
Water Quality Supervisgi
�4- Z 3-9,
Date

cc: Permits and Engineering
Technical Support Branch
Public Water Supply Section
County Health Dept.
Central Files
WSRO
SOC PRIORITY PROJECT: No x
To: Permits and Engineering Unit
Water Quality Section
Attention: Dana Bolden
Date: June 27, 1995
NPDES STAFF REPORT AND RECOMMENDATION
County Watauga
Permit No. NC0027286
PART I - GENERAL INFORMATION
1. Facility and Address: Town of Blowing Rock
The Honorable Rufus E. Hallmark, Mayor
P. O. Box 47
Blowing Rock, N.C. 28605
2. Date of Investigation: June 21, 1995
3. Report Prepared by: Mike Mickey, Environmental Specialist II
4. Persons Contacted and Telephone Number: Mr. Tom McRary, ORC, (704) 295-
5226(WWTP), 295-5225(WTP); 295-5200(town hall).
5. Directions to Site: Take Hwy 321 south out of Boone. After crossing under the Blue
Ridge Parkway, the WWTP entrance is 0.6 mile on the right.
6. Discharge Points(s), List for all discharge points:
Latitude: 36° 08' 32" Longitude: 81° 40' 10"
U.S.G.S. Quad No. C-12-NW U.S.G.S. Quad Name Boone
7. Site size and expansion area consistent with application? X Yes No If No, explain:
8. Topography (relationship to flood plain included): The WWTP is located above the flood
plain.

9. Location of nearest dwelling: No dwellings are located within 500 feet of the outfall.
10. Receiving stream or affected surface waters:
Middle Fork South Fork New River.
a. Classification WS-IV
b. River Basin and Subbasin No.: 05-07-01
c. Describe receiving stream features and pertinent downstream uses: The Town of
Boone has an emergency raw water intake on the Middle Fork South Fork New
River approximately five miles downstream of Blowing Rock's outfall. Under
normal flow conditions, the Town of Boone obtains raw water from their Winkler
Creek intake.
Part II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of Wastewater to be permitted: 0.80 MGD (Ultimate Design Capacity)
b. What is the current permitted capacity of the Waste Water Treatment facility?
0.80 MGD
c. Actual treatment capacity of the current facility (current design capacity)? Same
as A & B above.
d. Date(s) and construction activities allowed by previous A/C's issued in the
previous two years. NA
e. Please provide a description of existing or substantially constructed wastewater
treatment facilities; The existing 0.80 MGD WWTP consists of the following:
Bar screen, grit chamber, influent flow meter, flow equalization basin, influent
pumps, d-box, aeration basins, secondary clarifiers, aerobic digester, gas
chlorination, chlorine contact basin, effluent flow meter, dechlorination unit
(sodium meta-bi-sulfate) post -air chamber and outfall pipe. Standby power is
available which runs the influent pumps only.
f. Please provide a description of proposed wastewater treatment facilities. NA
g.
Possible toxic impacts to surface waters: None known. The facility has passed
all quarterly bioassays since 1991.
h. Pretreatment Program (POTWs only): NA - Blowing Rock receives strictly
domestic wastewater from 850 residential customers and various commercial/retail
customers. The WWTP does receive filter backwash from the water treatment
plant (approximately 60,000 gallons) every 10 days.
NPDES Permit Staff Report
Version 10/92
Page 2

2. Residuals handling and utilization/disposal scheme:
a. Other disposal/utilization scheme (Specify): Currently, the Town of Blowing
Rock does not have a permitted method of sludge disposal. According to the
sludge management plan submitted with their application, the town is currently
negotiating an agreement with Boone or Lenoir to accept their sludge and dispose
of it under their respective non -discharge permits.
3. Treatment plant classification (See attached rating sheet). Class III (52 points).
4. SIC Code(s): 4952
Primary 01 Main Treatment Unit Code: 0 5 0 X 0
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Grant Funds or are any public monies involved.
(municipals only)? NA
2. Special monitoring or limitations (including toxicity) requests: NA
3. Important SOC, JOC or Compliance Schedule dates: NA
4. Alternative Analysis Evaluation: Has the facility evaluated all of the non -discharge
options available. Please provide regional perspective for each option evaluated. NA
for existing POTW.
5. Other Special Items: None.
PART IV - EVALUATION AND RECOMMENDATIONS
The Blowing Rock POTW is currently operating in compliance with their permit limits.
The POTW only receives domestic waste from retail and residential customers. The two main
concerns noted during the site evaluation are as follows:
1. The Town of Blowing Rock does not have an approved sludge disposal
method/permit. Currently the one aerobic sludge digester and the two aeration
basins converted into sludge holding basins are full. The operator cannot decant
anymore to gain further sludge capacity. The renewal application indicated that
Blowing Rock was negotiating an agreement with Boone or Lenoir to accept their
sludge. To date, no agreements have been reached.
NPDES Permit Staff Report
Version 10/92
Page 3

2. The effectiveness of the town's dechlorination unit is questionable. Previously,
the POTW attempted to dechlorinate with their post -air chambers. Since this
proved unreliable, the town installed (without an AJC) a chemical feed (sodium
metabisulfite) dechlorination system. Unfortunately, the feed is not constant and
variable total residual chlorine (TRC) results are obtained. WSRO measured the
TRC on 6/21 at 1090 ug/1. The limit is 5.0 ug/1.
WSRO recommends that the NPDES permit not be reissued until the following information is
provided to DEM:
a) A copy of the written agreement with either the Town of Boone or Lenoir
indicating their acceptance of Blowing Rocks sludge.
b) The submittal of a complete permit modification request from either the Town of
Boone or Lenoir requesting DEM's approval to accept and dispose of Blowing
Rock's sludge.
Signature of report prepare
Water Quality Regional Supervisor
�-. 5- 9 5
Date
NPDES Permit Staff Report
Version 10/92
Page 4

RATING SCALE FOR CLASSIFICATION OF WATER POLLUTION CONTROL SYSTEMS
Name of Facility: f OLA 0-1 tac J i ✓ cj P-cci- VV VVf P
Owner or Contact Person: 1l.(_ 1(cwwrcJ (F 'Rufus -{4-a 11Hitds><, Mayer
Mailing Address: P.0 Cx -a 7 l�lc LG iv( Pcc k, /VC.
County: (k1a Cc, Telephone: 7)4 ZT 3 5276 ( iji'wp)
Present Classification: C hiss New Facility Existing Facility h'
NPDES Per. No. NCO() 2-72 Nondisc. Per. No.WQ Health Dept.Per No.
Rated by: F1IC"±t, 1 Telephone: 1(1C771-ii('CO Date: !G-ZZ_-`I'%,
Reviewed by: Health Dept.
Regional Office
Central Office
Grade: I
OR C: 4Y1 itic .1 y
Check Classification(s): Subsurface Spray Irrigation
Wastewater Classification: (Circle One) I it III ' IV
Telephone:
Telephone: i ( 771 . C('
Telephone:
Telephone: f%'4Z9SZZ4:
Land Application
Total Points: s7
IN -PLANT PROCESSES AND RELATED CONTROL EQUIPMENT WHICHARE AN INTEGRAL PART OF INDUSTRIAL PRODUCTION SHALL NOT BE
CONSIDERED WASTE TREATMENT FOR THE PURPOSE OF CLASSIFICATION. ALSO SEPTIC TANK SYSTEMS CONSISTING ONLY OF SEPTIC TANK
AND GRAVITY NITRIFICATION LINES ARE EXEMPT FROM CLASSIFICATI4Pl,
SUBSURFACE CLASSIFICATION
(check all units that apply)
1. septic tanks
2. pump tanks
3. siphon or pump -dosing systems
4. sand filters
5. grease trap/interceptor
6. oil/water separators
7. gravity subsurface treatment and disposal:
8. pressure subsurface treatment and disposal:
SPRAY IRRIGATION CLASSIFICATION
(check all units that apply)
1. preliminary treatment (definition no. 32 )
2. lagoons
3. septic tanks
4. pump tanks
5. pumps
6. sand filters
7. grease trap/interceptor
8. oil/water separators
9. disinfection
10. chemical addition for nutrient/algae control
11. spray irrigation of wastewater
In addition to the above classifications, pretreatment of wastewater In excess of these components shell
be rated using the point rating system and will require an operator with an appropriate dual certification.
LAND APPLICATION/RESIDUALS CLASSIFICATION (Applies only to permit holder)
1. Land application of biosolids, residuals or contaminated soils on a designated site.
WASTEWATER TREATMENT FACILITY CLASSIFICATION
The following systems shall be assigned a Class I classification unless the flow is of a significant quantity or the technology is unusually
complex, to require consideration by the Commission on a race -by -case basis: (Check if Appropriate)
1. OiVwater Separator Systems consisting only of physical separation, pumps and disposal;
2. Septic Tank/Sand Fitter Systems consisting only of septic tanks, dosing apparatus, pumps,sand fitters, disinfection
and direct discharge;
3. Lagoon Systems consisting only of preliminary treatment, lagoons, pumps, disinfection, necessary chemical treatment for
algae or nutrient control, and direct discharge;
4. Closed -loop Recycle Systems;
5. Groundwater Remediation Systems consisting only of oil/water separators, pumps, air -stripping, carbon adsorption, disinfection
and dispo„I;
6. Aquaculture operations with discharge to surface waters;
7. Water Plant sludge handling and back -wash water treatment;
8. Seafood processing consisting of screening and disposal.
9. Single-family discharging systems, with the exception of Aerobic Treatment Units, will be classified if permitted after July 1,
1993 or it upon inspection by the Division, it is found that the system is not being adequately operated or maintained. Such
systems will be notified of the classification or reclassification by the Commission, in writing.

The following scale is used for rating wastewater treatment facilities: (circle appropriate points)
ITEM POINTS
(1) Industrial Pretreatment Units or Industrial Pretreatment Program (see definition No. 33) 4
(2) DESIGN FLOW OF PLANT IN gpd (rot applicable to non -contaminated cooling waters, sludge handling facilities for
water purification plants. totally closed cycle systems(see definition No. 11), and facilities consisting only of item
(4)(d) or Items (4)(d) and (11)(d))
0 - 20,000 1
20,001 - 50,000 2
50,001 - 100,000 .3
100,001 • 250,000 4
250,001 - 500,000 .5
500.001 - 1,000,000
1,000,001 - 2,000,000 10
2.000.001 (and up) rate 1 point additional for each 200,000 gpd capacity up to a maximum of 30
Design Flow (gpd) G. €, rl'I&D
(3) PRELIMINARY UNiTS/PROCESSES (see definition No.32) (a) Bar Screens 4� �--�
or
(b) Mechanical Screens, Static Screens or Comminuting Devices 2
(c) Grit Removal
ar
(d) Mechanical or Aerated Grit Removal 2
(e) Flow Measuring Device 1
or
(f) Instrumented Flow Measurement
(g) Preaeratlon 2
(h) Influent Flow Equalization
(i) Grease or Oil Separators - Gravity 2
Mechanical 3
Dissolved Air Flotation .8
(j) Prechlorinatlon .5
(4) PRIMARY TREATMENT IIJRS/PROCESSES
(a) Septic Tank (see definition No. 43) 2
(b) Imhoff Tank .5
(c) Primary Clarifiers .5
(d) Settling Ponds or Settling Tanks for Inorganic Non -toxic Materials (sludge handling facilities for water
purification plants. sand, gravel, stone, and other mining operations except recreational activities such as gem
or gold mining) 2
(5) SECONDARYTREATMBJTUNRS/PROCESSES
(a) Carbonaceous Stage
(I) Aeration -High Purity Oxygen System 20
Diffused Air System
Mechanical Air System (fixed, floating or rotor) .8
Separate Sludge Reaeration .3
(II) Trickling Filter
High Rate 7
Standard Rate .5
Packed Tower .5
(ill) Biological Aerated Filter or Aerated Biological Filter 10
(iv) Aerated Lagoons 10
(v) Rotating Biological Contactors 10
(vi) Sand Filters -intermittent biological 2
Recirculating biological .3
(vii) Stabilization Lagoons .5
(vill) Clarifier
(Ix) Single stage system for combined carbonaceous removal of BOD and nitrogenous removal by
nitrification (see definition No. 12)(Points for this item have to be in addition to Items
(5)(a)(I) through (5)(a)(viii),
utilizing the extended aeration process (see definition No.3a) 2
utilizing other than the extended aeration process 8
(x) Nutrient additions to enhance BOD removal 5
(xl) Biological Culture ('Super Bugs')addition 5
(b) Nitrogenous Stage
(I) Aeration - High Purity Oxygen System 20
Diffused Air System 10
Mechanical Air System (fixed. floating or rotor) .8
Separate Sludge Reaeration .3
(II) Trickling Filter -High Rate 7
Standard Rate 5
Packed Tower .5
(111) Biological Aerated Filter or Aerated Biological Filter 1 0
(Iv) Rotating Biological Contactors 10
(v) Sand Fitter - Intermittent biological 2
Recirculating biological 3
(v1) Clarifier 5
(6) TERTIARY OR ADVANCED TREATMENT UNITS/PROCESSES
(a) Activated Carbon Beds -
without carbon regeneration .5
with carbon regeneration 15
(b) Powdered or Granular Activated Carbon Feed -
without carbon regeneration .5
with carbon regeneration 15
(c) Alr stripping .5
(d) Denitrfficatton Process 10
(e) Electrodialysis 5
(f) Foam Separation 5
(g) Ion Exchange .5
(h) Land Application of Treated Effluent (see definition No. 22b) (not applicable tor sand, gravel. stone
and other similar mining operations) by high rate Infiltration 4
(I) Microscreens .5
(j) Phosphorous Removal by Biological Processes (See delinttlon No. 26) 20
(k) Polishing Ponds - without aeration 2
with aeration .5

(I) Post Aeration - cascade 0
diffused or mechanical
(m) Reverse Osmosis
(n) Sand or Mixed -Media Filters - low rate 2
high rate 5
(o) Treatment processes for removal of metal or cyanide 15
(p) treatment processes for removal of toxic materials other than metal or cyanide 15
(7) SLUDGE TREATMENT
(a) Sludge Digestion Tank - Heated (anaerobic) 10
Aerobic
Unheated (anaerobic) 3
(b) Sludge Stabilization (chemical or thermal)
.5
(c) Sludge Drying Beds -Gravity 2
Vacuum Assisted .5
(d) Sludge Elutriation
5
(e) Sludge Condltloner (chemical or thermal) 5
(f) Sludge Thickener (gravity) 5
(g) Dissolved Air Flotation Unit [not applicable to a unit rated as (3)(i)] 8
(h) Sludge Gas Utilization (including gas storage) 2
(1) Sludge Holding Tank - Aerated .5
Non -aerated
2
(j) Sludge Incinerator (not including activated carbon regeneration) 10
(k) Vacuum Filter, Centrifuge, or Filter Press or other similar dewatering devices 10
RESIDUALS UTILIZATION/DISPOSAL (including incinerated ash)
(a) Lagoons 2
(b) Land Application (surface and subsurface) (see definition 22a)
by contracting to a land application operator or landfill operator who holds the land application permit
or landfill permit 2
(c) Dedicated Landfill(burial) by the permittee of the wastewater treatment facility 5
(9) DCT]t 7V
(a) Chlorination
(b) Dechiorination
(c) Ozone
(d) Radiation 5
5
(1 0) CHEMICAL ADDITION SYSTEM(S) ( see definttlon No. 9) [not applicable to chemical additions rated as hem (3)(J),
(5)(a)(xi), (6)(a), (6)(b), (7)(b), (7)(e), (9a), (9)(b) or (9)(c) 5 points each:
List
(8)
(1 1) MISCELLANEOUS UNRSvPROCESRFS
(a) Holding Ponds, Holding Tanks or Settling Ponds for Organic or Toxic Materials Including wastes from mining
operations containing nitrogen or phosphorus compounds In amounts significantly greater than Is common
for domestic wastewater 4
(b) Effluent Flow Equalization (not applicable to storage basins which are inherent In land application systems) 2
(c) Sumps Discharge (not applicable to storage basins inherent in land application systems) 5
(e) Stand -By Power Supply
(f) Thermal Pollution Control Device
5
5
5
TOTAL POINTS
CLASSIFICATION
Class I 5-25 Points
Class II 26-50 Points
Class III 51-65 Points
Class N 66-Up Points
.3
Facilities having a rating of one through four points, Inclusive, do not require a certified operator.
Facilities having an activated sludge process will be assigned a minimum classification of Class II.
Facilities having treatment processes for the removal of metal or cyanide will be assigned a minimum classification of Class II.
Facilities having treatment processes for the biological removal of phosphorus will be assigned a minimum classification of Class III.
.0004 DEFINITIONS
The following definitions shall apply throughout this Subchapter.
(1) Activated Carbon Beds. A physical/chemical method for reducing soluble organic material from wastewater effluent; The column -type beds used in this
method will have a flow rate varying from two to eight gallons per minute per square foot and may be either upflow or downflow carbon beds. Carbon may or
may not be regenerated on the wastewater treatment plant she;
(2) Aerated Lagoons. A basin in which all solids are maintained In suspension and by which biological oxidation or organic matter is reduced through artificially
accelerated transfer of oxygen on a flow -through basis;
(3) Aeration. A process of bringing about intimate contact between alr or high purity oxygen In a liquid by spraying, agitation or diffusion;(3a) Extended
Aeration. An activated sludge process utilizing a minimum hydraulic detention time of 18 hours.
(4) Agriculturally managed site. Any she on which a crop Is produced, managed. and harvested (Crop Includes grasses, grains, trees, etc.);
(5) Air Stripping. A process by which the ammonium ion is first converted to dissolved ammonia (pH adjustment) with the ammonia then released to the
atmosphere by physical means; or other similar processes which remove petroleum products such as benzene, toluene, and xylene;
(6) Carbon Regeneration. The regeneration of exhausted carbon by the use of a fumace to provide extremely high temperatures which volatilize and oxidize the
absorbed Impurities;
(7) Carbonaceous Stage. A stage of wastewater treatment designed to achieve 'secondary' effluent limits;
(8) Centrifuge. A mechanical device In which centrifugal force Is used to separate solids from liquids or to separate liquids of different densi.as;
(9) Chemical Addition Systems- The addition of chemical(s) to wastewater at an application point for purposes of improving solids removal, pH adjustment,
alkalinity control. etc.; the capability to experiment with different chemicals and different application points io achieve a specific result will be considered one
system; the capability to add chemical(s) to dual units will be rated as one system; capability to add a chemical at a different application points for different
purposes will result in the systems being rated as separate systems;
(10) Chemical Sludge Conditioning. The addition of a chemical compound such as lime, ferric chloride, or a polymer to wet sludge to coalesce the mass prior to
Its application to a dewatering device;
(11) Closed Cycle Systems. Use of holding ponds or holding tanks for containment of wastewater containing Inorganic, non -toxic materials from sand, gravel,
crushed stone or other similar operations. Such systems shall carry a maximum of two points regardless of pumping facilities or any other appurtenances;
(12) Combined Removal of Carbonaceous BOO and Nitrogenous Removal by Nitrification- A single stage system required to achieve permit effluent limits on BOD
and ammonia nitrogen within the same biological reactor,
(13) Dechlorination. The partial or complete reduction of residual chlorine in a liquid by any chemical or physical process;
(14) Denitrilication Process. The conversion of nitrate -nitrogen to nitrogen gas;