NC0021890_wasteload allocation_19830201

NPDES DOCUWEMT SCANNIM6 COVER :iMEET
NPDES Permit:
NC0021890
Granite Falls WWTP
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)
Document Date:
February 1, 1983
This document is printed on reuse paper - ignore vmy
content on the side

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NPDES WASTE LOAD ALLOCATION
Facility Name: Lrrrcn ir. Its %awn o ✓W7P Date: ////okL
Existing 71 Permit No.: NC OOS-S—o 3 q- pipe No.: County: Z-
Proposed FLI
Design Capacity (MGD): 40.SY6 S Industrial (% of Flow) : 0 Domestic (% of Flow): / o c�
Receiving Stream: Cadawix /over- -Z_r,k Ackorgi Class:--jil'�'&Aub-Basin: 03-ot-32
Reference USGS Quad: /¢&4tPl (Please attach) Requestor: Regional Office /_02rM4
(Guideline limitations, if applicable, are to be listed on the back of this form.)
Design Temp.: % L Drainage Area: l Q 9 0 utr �"' Avg. Streamflow: �'f 0
7Q10: Q Q 4 c-L _ -_ Winter 7Q10: 30Q2:
Location of D.O.minimum (miles below outfall): 0 Slope: O
Velocity (fps): Kl (base e, per day, 2000 : 0.ZG K2 (base e, per day, 201C):
Effluent
Characteristics
Monthly
Average
Comments
0
i
oe• o
Effluent
Original Allocation ko'�X O 'i, �Ot 4r107L
Revised Allocation a Date(s) of Revision(s)
m� (Please attach previous allocation) -
Y Prepared By: ✓ r Reviewed By: Date:
.Qi�Y
Comments

REQUEST NO. : 492
**************##*#**# WASTELOAD ALLOCATION APPROVAL FORM
FACILITY NAME
TYPE OF WASTE
COUNTY
REGIONAL OFFICE
RECEIVING STREAM
7010 : 288 CFS
DRAINAGE AREA
TOWN OF GRANITE FALLS
DOMESTIC
CALDWELL
E��UI�19�i�iQAa-9 a[klll�i�l."�i:71� ii:7l
L. HICKORY SUDBASIN : 03-08-32
W7010 : -- CFS 3002 - CFS
1090 SO.MI. STREAM CLASS :A -II
#****#****###*#***#***
RECOMMENDED EFFLUENT LIMITS
***f**************
i
WASTEFLOW(S)
(MGD)
.865
DOD-5
(MG/L)
:
30
NH3-N
(MG/L)
:
NR
D.O.
(MG/L)
NR
AIR C
PH
(SU)
:
NR THIS
IS A NEW L0117I0M.
FECAL COLIFORM
(/100ML):
1000
TSS
(MG/L)
30
********************************************************************************
FACILITY IS : PROPOSED (ob EXISTING ( 7 NEW ( )
LIMITS ARE : REVISION ( ) CONFIRMATION ( ) OF THOSE PREVIOUSLY ISSUED
REVIEWED AND RECOMMENDED BY:
MODELER
SUPERVISORYMODELING GROUP
REGIONAL SUPERVISOR
PERMITS MANAGER
APPROVED BY :
DIVISION DIRECTOR
.I".`.j__-DATE :__L�Z�f D3
--BATE LP4 3
: _�-- ------- ------BATE : /
- --_------BATE :-Jgl-�_�-_
:G"---------BATE

�w k � � �� �. �k.�-�Y
__ _l _ - -
_._I ✓y..�� ��..

~ "^ ~
DISCHARGER ` '
�
TOWN OF
GRANITE FALLS
NAME OF L-AKE.�/
HICKORY
DEPTd
10,00
FEET
WIDTH
1000^00
FEET
FRESHWATER INFLOW
1
288,00
CFS
WASTEWATER FLOW
ULT^ BOD OF WASTE
1
�
0.97
11O,OO
MOD
MG/L ~now
MAX TIDAL VELOCITY
�
�O^OO
KNOTS
CROSS -SECTION -AREA
110000~00
SQ.FT,
ADVECTIVE VEL^
0^47
MI/DAY
DISPERSION
- 0.10
SQ^MI./DAY
01
0,39
PER DAY '
K2
\
O + 20
.
PERDAY
BOD AT OUTFALL = 106686341433 MG/L^
D.O. AT OUTFALL = 6,52588216175 MOIL
`
'
`
MILEPOINT UPSTREAM BOD 'UPSTREAM D.O.
`
0.00 1.97 603
/ .
MILEPOINT
DOWNSTREAM BOD
'
DOWNSTREAM DO
O^OO
1^97
6,53
00'
1^71
6,33
0.40
1.48
� ' 6,17
0,60
1,28
6,06
0,80
1.11
5,98
1^00
0^96
5~92
1420
0,84
5.89
1^40
0^73
5^87
1.60
0^63
5^87.
1^80
0^55
5^88
2,00
0.47
5.90
2^20
O^41
5^93
2^40
0+36
5.96
2,60
0,31
5^99
2~80
0^27
6,03
3^00
. 0~23
6^07
3,20
0.20
6^11
3,40
'O^17
6Y16
3,60
0,15'
6^20 '
3^80
0^13
6~24
4,00
0^11
6^28
n
THE WASTELOAD ALLOCATION FOR TOWN OF GRANITE FALLS IS 110 MOIL ,

DIVISION OF ENVIRONMENTAL MANAGEMENT
November 16, 1982
M E M O R A N D U M
TO: Dick Peace, Regional Supervisor
Mooresville Regional Office
FROM: Mark Lewis, Environmental Engineer I ),k ';Z5
Technical Services Branch
THROUGH: Randy Williams, Supervisor /Z
Point Source Modeling Group
SUBJECT: In -Stream Assessment
Granite Falls WWTP
Granite Falls, Caldwell County
Per your request, a "Level B" analysis has been completed for the Town
of Granite Falls WWTP discharge into Gunpowder Creek. This is a "C" class
stream. At the point of discharge, the creek has a drainage area of 36 mi2
yielding a 7Q10 of 7.2 cfs.
There is a small dam located approximately 0.4 miles below the discharge
point on Gunpowder Creek. The plant actually discharges into the backwaters
of the lake created by the dam. The velocity in the lake was estimated to
be 0.009 f.p.s. Beyond the dam, Gunpowder Creek becomes the backwaters of
Lake Hickory (Class A -II and B); the lake is located 3.4 miles beyond the dam.
According to Arthur Mouberry the town of Granite Falls has received approval
for three additions to their wastewater treatment plant. These approvals were
for 32,700 gpd (7/82), 21,900 gpd (4/82), and 600 gpd (8/82). Presently, the
town is requesting another increase of 11,250 gpd. In order to assess the
impact of all these increases, the model was run assuming an addition of 66,450
gpd.
V
Given present treatment plant conditions, a "Level B" analysis indicates
that at summer 7Q10 conditions a DO sag of 6.9 mg/l is expected to occur approxi-
mately 0.1 miles above the dam (0.3 miles below the discharge). With the requested
addition of 66,450 gpd, the DO sag is predicted to drop by only 0.2 mg/l; the
location of the sag will remain the same. Once over the dam, the water quality
of Gunpowder Creek is expected to return to background quality.
Since the additional wasteflow is domestic and adequate disinfection is
being applied, minimal impact should occur to A -II waters which are located
3.8 miles below the discharge. No evidence exists to suggest that toxics are
a problem below the Granite Falls outfall. The Granite Falls WWTP is discharging
an effluent low in fecal coliform; assuming treatment plant efficiency remains
the same, the proposed increase should not affect the use of Lake Hickory as a
"B" class water.

-2-
Analysis
Self -monitoring data averaged from April through August, 1982 indicates
that the Granite Falls effluent has the following relevant characteristics:
Flow
= 0.21 MGD
BOD5 =
17.7 mg/1
NH3-N
= 6.4 mg/l
D.O.
= 4.5 mg/1
BOD ultimate
= BOD5+4(NH3-N)=43.3 mg/l
Using the above parameters, the model was run at 7Q10 summer conditions for
the present flow as well as the proposed expansion of 66,450 gpd. The same
treatment efficiency was assumed in both cases.
The results of the model indicate that a DO minimum of 6.9 mg/1 is expected
0.3 miles below the discharge point given present plant flow. The addition of
0.066 MGD is predicted to lower the DO sag to 6.7 mg/l; however, the.location
of the sag will not be affected. With or without the requested addition, the
water quality of Gunpowder Creek is expected to return to background conditions
within 0.5 miles of the outfall. Self -monitoring data tend to support the
above predictions (Table A). Self -monitoring reports analyzed from September
1981 through August, 1982 indicate that the lowest monthly DO average downstream
of the discharge was 7.0 mg/l. However, the downstream monitoring station is
located only 500 ft. below the discharge. The model predicts the DO sag to
occur 0.3 miles below the outfall. Thus, the actual DO minimums may be somewhat
lower than self -monitoring reports indicate.
Since the requested additions will be domestic, the additional wasteflow
should have minimal impact on the drinking water supplies of Lake Hickory. The.
fecal coliform data from self -monitoring reports does appear to be suspect
(Table A). Throughout the summer months the data indicates that most of the -
effluent fecal values are less than 2/100 ml. Yet, there does appear to be a.
general increase in downstream fecal coliform values during this same period.
However, the highest downstream value recorded was 430/100 ml. Most of the down-
stream values were 300/100 ml or less.
Given the 3.8 miles of backwater conditions until Gunpowder Creek enters
the "B" class waters of Lake Hickory, it is likely that the fecal coliform
values would fall well below the water quality standard of 200/100 ml. Thus,
assuming that the Granite Falls WWTP maintains its present disinfection capa-
bilities, the requested addition should not have an adverse impact on Lake
Hickory as a "B" class water.
If you have_any further questions, please call.
cc: Arthur Mouberry
Attachment

Month
September
October
November
December
January
February
March
April
May
June
July
August
Year
81
81
81
81
82
82
82
82
82
82
82
82
DO Upstream
7.5
9.0
10.3
12.3
12.2
11.6
11.1
10.1
8.0
7.7
7.3
7.6
TABLE A
Granite Falls WWTP
Self -Monitoring Data
DO Downstream
(mg/1)
7.0
8.7
10.1
12.1
12.1
11.6
11.0
10.0
8.3
8.3
7.2
7.4
Fecal Coliform
Effluent
(#11,00 ml)
70
70
60
<4
<4
<4
<2
<2
<2
<2
<2
<2
Fecal Coliform
Upstream
(#1100 ml)
100
100
10
10
80
120
<20
130
120
70
180
850
Fecal Coliform
'Downstream
01100 ml)
130
130
195
<4
<4
60
<20
280
240
270
430
100