NC0029572_Instream Assessment_19930910

NPDES DOCUMENT SCANNIN` COVER !;FIEET
NPDES Permit:
NC0029572
Farmville WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
September 10, 1993
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North Carolina Division of Environmental Management
Water Quality Section / Rapid Assessment Group
September 10, 1993
MEMORANDUM
To: Robert Tankard !
From: Farrell Keough,
Through: Carla Sanderson
Ruth Swanek k(�
Subject:
Summary
Wasteload and Limits Assessment
Town of Farmville Waste Water Treatment Plant
NC0029572 Little Contentnea Creek [03-04-07]
Pitt County Washington Region
A waste loading and permit limit evaluation for the Town of Farmville has been completed by Technical
Support. The Washington Regional Office has requested this assessment due to the facility's inability to
meet various metals and toxicity limits. In addition, the Town of Farmville has requested an additional
75,000 gallons per day (gpd) of domestic wasteflow and 100,000 gallons per day (gpd) of industrial,
(treated to domestic strength) wasteflow to its plant. Due to the fact that no change in limits on oxygen
consuming parameters was requested, a Level-B modeling analysis using the 67 (b) criteria was not
necessary.
Evaluation & Discussion
The Town of Farmville discharges into the Little Contetnea Creek, a class "C - Swamp NSW" waterbody in
the Neuse River Basin. The Little Contetnea Creek drains into Contetnea Creek which drains into the
Neuse River watershed. At the Farmville discharge location, the drainage area is estimated to be 64.3
square miles. The USGS estimates the following flows at the discharge site:
summer 7Q10 flow = 0.071 cfs
winter 7Q10 flow = 0.90 cfs
Average flow = 78.0 cfs
The segment of the waterbody where Farmville discharges is slow moving with a bed gradient of
approximately six (6) feet per mile for less than three (3) miles, then flattening out to approximately three
(3) feet per mile for the next eight (8) miles.

.4
The parameters concerned in this SOC include Total Phosphorus, (4 mg/I is the requested SOC limit), Chronic
Toxicity (Ceriodaphnia) Testing, Cyanide, Mercury, and Nickel, (monitoring is the requested SOC requirement for
these latter four (4) parameters). As a brief outline of the various problems this facility is having with its current
limits, the following table identifies the facility's current permit limits and the highest DMR value over the
past twelve (12) months:
Parameter Concerned Current Permit Limit
Total phosphorus (mg/I):
Cyanide (µg/I):
Mercury (µg/I):
Nickel (µg/I):
Chronic Toxicity (Ceriodaphnia) Test at 90% :
2.0
5.0
0.012
89.0
P/F
Highest DMR value
[7/92 to 6/93]
6.0
27.0
0.40
263.0
facility has had consistent
failures since September, 1992
The Town of Farmville has initiated a four (4) phase program to address and inevitably remedy the toxicity
problems plaguing its facility. The first phase, begun on August 1, 1993 will include an attempt to
characterize the Town's' wasteflow. This phase will assist the facility by validating whether the
constituents entering the plant are treatable, whether a particular Industrial discharger is unduly adding to
the toxicity problem(s), and will characterize for Farmville current baseline data with which to gauge
improvements against. Phase two (2), scheduled to begin on or before April 1, 1994, will intensify
analysis of the results obtained from the previous characterization. Phase three (3) is scheduled to begin
on or before April 1, 1995. This phase will also intensify analysis results obtained from the previous
phases of the study, as well as initiating a Toxics Reduction Program. Phase four (4) will be an ongoing
study designed primarily for treatment plant final effluent.
Recommendations
EMC criteria states that no industrial sources should be added under a Special Order of Consent, (SOC).
DEM interprets this as "no toxics in toxic amounts". Therefore, it is recommended that this SOC be
limited to "domestic strength" waste flow additions only. Due to the difficulties surrounding identification
of toxicity problems, milestones should be included in the schedule for the facility to ensure inevitable
compliance with the final limits for Total Phosphorus, Cyanide, Mercury, Nickel, and Whole Effluent
Toxicity. The Technical Support Branch will concur with the proposed SOC limits of:
Effluent Characteristics
BOD5 (mg/I):
NH3-N (mg/I):
DO (mg/I):
TSS (mg/I):
Fecal Coliform (/100 ml):
pH (SU):
Total phosphorus (mg/I):
Cadmium (µg/I):
Chromium (µg/I):
Cyanide (µg/I):
Lead (µg/I):
Mercury (µg/1):
Nickel (µg/I):
Chronic Toxicity (Ceriodaphnia) Test at 90% :
Summer [Monthly]
9.0
1.0
5.0
30
200
6-9
4.0
2.0
50
monitor
25
monitor
monitor
monitor
Winter [Monthly]
18.0
2.0
5.0
30
200
6-9
4.0
2.0
50
monitor
25
monitor
monitor
If there are any further questions regarding these recommendations, please feel free to contact me.
cc: Kent Wiggins
Central Files

RECEIVING
r,
A. Why" is SOC needed?
(Facility. is out of compliance with which:
effluent limits?)
2 / P:1 •L�- • Ali LrC C t_ �t' 2 •`ter d Y ' \S _ ��
v yi F C.��"� a ` �L3 �, ,
r ,
tt�i� C i• tom, C v,u "Tci ;°U Ti,� f'^_
3. History of SOC request's: T Yc �
1. Monthly Average waste flow
prior to any SOC
•. Time period averaged
2. Previously approved SOC'
total of previously approved SOC flow:
Flows lost from plant
(facilities _that• have flow:
off line) __ gone
current SOC request flow:
. Total plant flow .post SOC
(sum of original' flow and.
SOC flow minus'`losses)
bl
>:p4 7'1
s{

C.
Please attach DMR pat year for all permitted
•
ters If poasjble, include
• ,
'reports from previous Years if
facility has been under' soc '• for more f•than a year. • • •
. .
CURRENT SOC RE
UEST
•
A .Requestis for domestic or industrial waste? If it is a combin--
ation, please specify percentages. -
B. What -type
nho 1/4.) s7",i2 y
E7.
nifrra "6".:
C. The region
proposes the following. SOC limits:
q c)-•
• NR3 6- 72,
DO L
TS S
(kflic307(._
• - -17.• CCI.016 1146'1)-i 727'
•,, • . : •
of industry? Please atiach-any pertinent data.
e041;! A-1-7- 7b
Q, e pid,,i0409 Age.)/7% 6/ 0.-‘) ioe-n4._6- •
SODS
•
mg/1_
• ' • ''
mg/1
3 0 mg/1
fecal coliform#/100m1
PH 9D (D.0 SU
-•,_ - ,-'174,4,:)•-• :". .., -
other parameters 7:;T•41_ Pitvz.Z-
c. 7,; vc i r
D. What is the basis for these limits?
- A excAiorix
Cbm--
,
"NJ •