Fact Sheet
The U.S. Environmental Protection Agency (EPA)
Proposes to Reissue a National Pollutant Discharge Elimination System
(NPDES) Permit to Discharge Pollutants Pursuant to the Provisions of the
Clean Water Act (CWA) to:
City of Worley Wastewater Treatment Plant
Public Comment Start Date: February 17, 2023
Public Comment Expiration Date: March 20, 2023
Technical Contact: Cody Piscitelli
(206) 553-1169
800-424-4372, ext. (within Alaska, Idaho, Oregon and Washington)
piscitelli.cody@epa.gov
EPA Proposes to Reissue the NPDES Permit
EPA proposes to reissue the NPDES permit for the facility referenced above. The draft
permit places conditions on the discharge of pollutants from the wastewater treatment plant
to waters of the United States. In order to ensure protection of water quality and human
health, the permit places limits on the types and amounts of pollutants that can be
discharged from the facility.
This Fact Sheet (FS) includes:
¦ information on public comment, public hearing, and appeal procedures
¦ a listing of proposed effluent limitations and other conditions for the facility
¦ a map and description of the discharge location
¦ technical material supporting the conditions in the permit
CWA § 401 Certification
The Coeur d'Alene Tribe has Treatment as a State (TAS) for CWA purposes for a portion of
the Reservation. The facility discharges to a portion of the Reservation where the Tribe
does not have TAS. Therefore, EPA is the certifying authority for this permit. See FS
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Section VI.C. Comments regarding the intent to certify should be directed to the EPA
technical contact listed above.
Clean Water Act §401 (A)(2) Review
CWA Section 401(a)(2) requires that, upon receipt of an application and 401 certification,
EPA must notify a neighboring State or Tribe with TAS when EPA determines that the
discharge may affect the quality of the neighboring State/Tribe's waters. As stated above,
EPA is the certifying authority and is accepting comment regarding the intent to certify this
permit. Once EPA reviews any comments received regarding the intent to certify and has
signed a final certification, EPA will determine whether the discharge may affect a
neighboring jurisdiction's waters. 33 U.S.C. § 1341(a)(2).
Public Comment
Persons wishing to comment on, or request a Public Hearing for, the draft permit may do so
in writing by the expiration date of the Public Comment period. A request for a Public
Hearing must state the nature of the issues to be raised as well as the requester's name,
address and telephone number. All comments and requests for Public Hearings must be in
writing and should be submitted to EPA as described below.
By the expiration date of the public comment period, all written comments and requests
must be submitted to Piscitelli.Cody@epa.gov.
After the Public Notice expires, and all comments have been considered, EPA's regional
Director for the Water Division will make a final decision regarding permit issuance. If no
substantive comments are received, the tentative conditions in the draft permit will become
final, and the permit will become effective upon issuance. If substantive comments are
received, EPA will address the comments and issue the permit.
After the Public Notice expires, and all comments have been considered, EPA's regional
Director for the Water Division will make a final decision regarding permit issuance. If no
substantive comments are received, the tentative conditions in the draft permit will become
final, and the permit will become effective upon issuance. If substantive comments are
received, EPA will address the comments and issue the permit. The permit will become
effective no less than 30 days after the issuance date, unless an appeal is submitted to the
Environmental Appeals Board within 30 days pursuant to 40 CFR § 124.19.
Documents are Available for Review
The draft NPDES permit, fact sheet, and other information can be downloaded from the
EPA Region 10 website at https://www.epa.gov/npdes-permits/about-region-10s-npdes-
perm it-program
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The draft NPDES permit, fact sheet and related documents are also available electronically
upon request by contacting Cody Piscitelli.
For technical questions regarding the permit or fact sheet, contact Cody Piscitelli at the
206-553-1169 or piscitelli.codv@epa.gov. Services can be made available to persons with
disabilities by contacting Audrey Washington at (206) 553-0523.
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Table of Contents
Acronyms 5
I. Background Information 7
A. General Information 7
B. Permit History 7
C. Tribal Consultation 7
II. Facility Information 8
A. Treatment Plant Description 8
B. Outfall Description 8
C. Effluent Characterization 8
D. Compliance History 9
III. Receiving Water 10
A. Water Quality Standards (WQS) 11
B. Receiving Water Quality 12
IV. Effluent Limitations and Monitoring 14
A. Basis for Effluent Lim its 17
B. Monitoring Requirements 25
C. Sludge (Biosolids) Requirements 28
V. Special Conditions 28
A. Nutrient Optimization Plan and Report 28
B. Quality Assurance Plan 28
C. Operation and Maintenance Plan 29
D. Sanitary Sewer Overflows and Proper Operation and Maintenance of the Collection
System 29
E. Environmental Justice 30
F. Standard Permit Provisions 30
VI. Other Legal Requirements 31
A. Endangered Species Act 31
B. Essential Fish Habitat 31
C. CWA § 401 Certification 31
D. Antidegradation 31
E. Permit Expiration 31
VII. References 32
Appendix A. Facility Information 33
Appendix B. Water Quality Data 35
Appendix C. Reasonable Potential and WQBEL Formulae 42
Appendix D, Reasonable Potential and WQBEL Calculations 47
Appendix E. Essential Fish Habitat Assessment 48
Appendix F. CWA 401 Certification 49
Appendix G. Antidegradation Analysis 50
Appendix H. Facility Map 52
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Acronyms
1Q10
7Q10
30B3
AML
AWL
BODs
°C
CFR
CSO
CV
CWA
DMR
DO
EFH
EPA
ESA
Gpd
HUC
ICIS
LA
lbs/day
LC
LC50
LD50
LTA
mg/L
mL
ML
)jg/L
mgd
MDL
MPN
N
NOAA
NPDES
O&M
1 day, 10 year low flow
7 day, 10 year low flow
Biologically-based design flow intended to ensure an excursion
frequency of less than once every three years, for a 30-day average flow.
Average Monthly Limit
Average Weekly Limit
Biochemical oxygen demand, five-day
Degrees Celsius
Code of Federal Regulations
Combined Sewer Overflow
Coefficient of Variation
Clean Water Act
Discharge Monitoring Report
Dissolved oxygen
Essential Fish Habitat
U.S. Environmental Protection Agency
Endangered Species Act
Gallons per day
Hydrologic Unit Code
Integrated Compliance Information System
Load Allocation
Pounds per day
Lethal Concentration
Concentration at which 50% of test organisms die in a specified time
period
Dose at which 50% of test organisms die in a specified time period
Long Term Average
Milligrams per liter
Milliliters
Minimum Level
Micrograms per liter
Million gallons per day
Maximum Daily Limit or Method Detection Limit
Most Probable Number
Nitrogen
National Oceanic and Atmospheric Administration
National Pollutant Discharge Elimination System
Operations and maintenance
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POTW Publicly owned treatment works
QAP Quality assurance plan
RP Reasonable Potential
RPM Reasonable Potential Multiplier
RWC Receiving Water Concentration
SS Suspended Solids
SSO Sanitary Sewer Overflow
s.u. Standard Units
TKN Total Kjeldahl Nitrogen
TMDL Total Maximum Daily Load
TRC Total Residual Chlorine
Technical Support Document for Water Quality-based Toxics Control
(EPA/505/2-90-001)
TSS Total suspended solids
USFWS U.S. Fish and Wildlife Service
WD Water Division
WET Whole Effluent Toxicity
WLA Wasteload allocation
WQBEL Water quality-based effluent limit
WQS Water Quality Standards
WWTP Wastewater treatment plant
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I. Background Information
A. GENERAL INFORMATION
This fact sheet provides information on the draft NPDES permit for the following entity:
Table 1. General Facility Information
NPDES Permit#:
ID0022713
Applicant:
Worley Wastewater Treatment Plant
City of Worley
Type of Ownership
POTW
Physical Address:
S 29401 B. Street
Worley, ID 83876
Mailing Address:
P.O. Box 219
Worley, ID 83876
Facility Contact:
Brenda Morris
City Clerk/Treasurer
worleyidclerk@aol.com
(208) 686-1258
Facility Location:
47.407778°N 116.920833°W
Receiving Water
North Fork Rock Creek
Facility Outfall
47.4078°N 116.920844°W
B. PERMIT HISTORY
The most recent NPDES permit for the City of Worley Wastewater Treatment Plant
(WWTP) was issued on March 10, 2015, became effective on May 1, 2015, and
expired on April 30, 2020. An NPDES application for permit issuance was submitted
by the permittee on November 15, 2019. EPA determined that the application was
timely and complete. Therefore, pursuant to Title 40 Code of Federal Regulations
(CFR) 122.6, the permit has been administratively continued and remains fully
effective and enforceable.
C. TRIBAL CONSULTATION
EPA consults on a government-to-government basis with federally recognized tribal
governments when EPA actions and decisions may affect tribal interests. Meaningful
tribal consultation is an integral component of the federal government's general trust
relationship with federally recognized tribes. The federal government recognizes the
right of each tribe to self-government, with sovereign powers over their members and
their territory. Executive Order 13175 (November, 2000) entitled "Consultation and
Coordination with Indian Tribal Governments" requires federal agencies to have an
accountable process to assure meaningful and timely input by tribal officials in the
development of regulatory policies on matters that have tribal implications and to
strengthen the government-to-government relationship with Indian tribes. In May 2011,
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the EPA issued the "EPA Policy on Consultation and Coordination with Indian Tribes"
which established national guidelines and institutional controls for consultation.
The City of Worley WWTP is located on the Coeur d'Alene Reservation of the Coeur
d'Alene Tribe. Consistent with the Executive Order and the EPA tribal consultation
policies, EPA coordinated with the Coeur d'Alene Tribe during development of the
draft permit and invited the Coeur d'Alene Tribe to engage in formal tribal consultation.
II. Facility Information
A. TREATMENT PLANT DESCRIPTION
1. Service Area
The City of Worley owns and operates the Worley WWTP located in Worley, ID.
The collection system has no combined sewers. The facility serves a resident
population of 550. There are no major industries discharging to the facility.
2. Treatment Process
The design flow of the facility is 0.0571 mgd. The reported actual flows from the
facility range from 0.165 to 0.365 (average monthly flow). The treatment process
consists of an aerated lagoon, a storage lagoon and chlorine disinfection. The
chlorine contact chamber passes underneath the storage lagoon from the vicinity
of the treatment control building to a manhole on the northern berm of the lagoon
system before discharging to North Fork Rock Creek. A schematic of the
wastewater treatment process and a map showing the location of the treatment
facility and discharge are included in Appendix A. Because the design flow is less
than 1 mgd, the facility is considered a minor facility.
B. OUTFALL DESCRIPTION
The outfall consists of a six-inch pipe one foot from the shore of North Fork Rock
Creek. The outfall diagram is shown in Appendix A. Under the previous permit, the
facility is only authorized to discharge from November 1st through June 30th provided
the flow in North Rock Creek provides a 10:1 dilution ratio. Over the past several
years, the facility has only discharged during the months of January through the end of
May.
C. EFFLUENT CHARACTERIZATION
To characterize the effluent, EPA evaluated the facility's application form, discharge
monitoring report (DMR) data, and additional data provided by the City of Worley. The
effluent quality is summarized in Table 2. Data are provided in Appendix B.
Table 2 Effluent Characterization
Parameter
Minimum
Maximum
Limit
TSS Concentration (7-day)
8.0 mg/L
29 mg/L
45 mg/L
TSS Concentration (30-day)
8.0 mg/L
29 mg/L
30 mg/L
TSS - % Removal
72%
96%
85% (minimum)
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Parameter
Minimum
Maximum
Limit
BOD Concentration (7-day)
2.9 mg/L
13.6 mg/L
45 mg/L
BOD Concentration (30-day)
2.9 mg/L
13.6 mg/L
30 mg/L
BOD5 - % Removal
70%
97%
85% (minimum)
TRC Concentration (daily maximum)
0.007 mg/L
0.520 mg/L
0.013 mg/L
TRC Concentration (30-day average)
0.001 mg/L
0.050 mg/L
0.011 mg/L
E. coli (instant maximum)
2.0
(CFU/100
mL)
230.0
(CFU/100
mL)
235.0
(CFU/100 mL)
E. coli (30-day geomean)
0.00
(CFU/100
mL)
2.76
(CFU/100
mL)
126.00
(CFU/100 mL)
Ammonia Concentration (as N) (daily maximum)
0.7 mg/L
10.9 mg/L
10.6 mg/L
Ammonia Concentration (as N) (30-day average)
0.0 mg/L
10.9 mg/L
4.1 mg/L
pH (instant minimum and maximum)
6.9 S.U.
8.0 S.U.
6.5-8.5 S.U.
Nitrate + Nitrite (as N) (3-day maximum)
0.0 mg/L
10.2 mg/L
--
Total Kjeldahl Nitrogen (as N) (30-day maximum)
3.7 mg/L
16.2 mg/L
--
Dissolved Oxygen (30-day minimum)
4.5 mg/L
11.7 mg/L
--
Temperature (30-day maximum)
O
o
CO
17.3 °Ci
--
Total Phosphorus (as P) (30-day maximum)
1.1 mg/L
4.0 mg/L
--
Notes
1. The temperature sample from March 2018 was entered as 43.00 °C, but likely the unit was
erroneously reported as °C instead of °F, meaning the sample was actually 6.11 °C. The actual
highest temperature sample was 17.34°C.
Source: DMR data from ICIS November 2016 - May 2021
D. COMPLIANCE HISTORY
A summary of effluent violations is provided in Table 3. The most common effluent
violation involves the exceedance of permitted discharge dilution flow rates, which
exceeded the limit of the previous permit in every one of the eight samples provided in
the last five years. In addition, the facility had numerous effluent limit violations over
the last permit term.
Additional compliance information for this facility, including compliance with other
environmental statutes, is available on Enforcement and Compliance History Online
(ECHO). The ECHO web address for this facility is: https://echo.epa.gov/detailed-
facilitv-report?fid=ID0022713&svs=ICP.
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Table 3. Summary of Effluent Violations
Parameter
Limit Type
Units
Number of
Instances
TSS
7-day Average Loading
lbs/day
7
TSS
30-day Average Loading
lbs/day
7
TSS Percent Removal
30-day Average
%
4
BODs
7-day Average Loading
lbs/day
2
BODs
30-day Average Loading
lbs/day
2
BOD Percent Removal
30-day Average
%
2
Total Residual Chlorine
Daily Maximim Concentration
mg/L
5
Total Residual Chlorine
Daily Maximum Loading
lbs/day
5
Total Residual Chlorine
30-day Average Loading
lbs/day
1
Ammonia
Daily Maximum Concentration
mg/L
1
Ammonia
Daily Maximum Loading
lbs/day
6
Ammonia
30-day Average Concentration
mg/L
5
Ammonia
30-day Average Loading
lbs/day
6
Effluent Dilution
30-day Minimum
ratio
8
Information accessed in ICIS/ECHO on June 27, 2021
EPA conducted an inspection of the facility in June, 2021. The inspection
encompassed the wastewater treatment process, records review, operation and
maintenance, and the collection system. Overall, the results of the inspection identified
issues with effluent limit violations, including 864 effluent limit exceedances between
March 2017 and April 2021, the Operation and Maintenance (O&M) plan, chain of
custody documents, the Quality Assurance Plan (QAP), missing Total Residual
Chlorine (TRC) progress report, misrepresentation of flow data, inadequate analytical
methods, and a missing Emergency Response and Public Notification Plan. A notice
of violation was issued in July 2022. In addition, the previous permit required the
completion of an inflow and infiltration study which the City completed in 2016. The
study noted significant inflow and infiltration into the City's collection system and
concluded that approximately 13,500 linear feet of the City collection system and 72
manholes are in need of repair and/or replacement.
III. Receiving Water
In drafting permit conditions, EPA must analyze the effect of the facility's discharge on the
receiving water. The details of that analysis are provided in the Water Quality-Based
Effluent Limits (WQBEL) section below. This section summarizes characteristics of the
receiving water that impact that analysis.
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This facility discharges to North Fork Rock Creek near the City of Worley, ID, which is on
the Coeur d'Alene Reservation in Kootenai County, before flowing into Washington State
waters approximately seven miles downstream, as displayed in Appendix H. The
confluence with Hangman Creek, a major tributary to the Spokane River, is approximately
27 miles downstream of the facility's outfall.
A. WATER QUALITY STAN DARDS (WQS)
CWA § 301(b)(1)(C) requires the development of limitations in permits necessary to
meet WQS. 40 CFR 122.4(d) requires that the conditions in NPDES permits ensure
compliance with the WQS of all affected States. A State's WQS are composed of use
classifications, numeric and/or narrative water quality criteria and an anti-degradation
policy. The use classification system designates the beneficial uses that each water
body is expected to achieve, such as drinking water supply, contact recreation, and
aquatic life. The numeric and narrative water quality criteria are the criteria deemed
necessary to support the beneficial use classification of each water body. The anti-
degradation policy represents a three-tiered approach to maintain and protect various
levels of water quality and uses.
The Coeur d'Alene Tribe has Treatment as a State (TAS) for CWA purposes for a
portion of the Reservation. As part of this TAS authority, the Tribe implements the
water quality standards program and has EPA-approved WQS applicable to the St.
Joe River and a portion of Lake Coeur d'Alene, referred to as the "Reservation TAS
Waters." In addition, for all other surface waters within the exterior boundaries of the
Coeur d'Alene Reservation, the Tribe has tribally-adopted WQS which they have not
submitted to EPA for approval. These waters are referred to as "Reservation Waters."
The Reservation TAS Waters are a subset of Reservation Waters. The "Reservation
Waters" and "Reservation TAS Waters" have similar WQS for pollutants of concern in
this permit.
The facility is located within the exterior boundaries of the Coeur d'Alene Reservation,
and discharges to Reservation Waters. The receiving water ultimately flows across the
Idaho-Washington border into Washington State waters. At no point is the receiving
water, downstream of the point of discharge, considered Reservation TAS Waters nor
Idaho State waters. Since the facility discharges to a portion of the Reservation where
the Tribe does not have TAS, EPA used the downstream Washington WQS as
reference for determining the permit limits to protect tribal designated uses and to
protect downstream uses in the State of Washington. EPA notes that the tribal WQS
which have not been submitted to the EPA are the same as or similar to the
Washington WQS, thus, application of the Washington WQS ensures that tribal waters
are protected. The distance from the point of discharge to the Washington-Coeur
d'Alene Reservation boundary is approximately seven miles.
1. Designated Beneficial Uses
The facility discharges to the North Fork Rock Creek (Hangman Creek Subbasin
Hydrologic Unit Code [HUC] 00017010306031), within the exterior boundaries of the
Coeur d'Alene Indian Reservation.
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Upon entering Washington State, Hangman Creek has the following designated uses
(WAC 173-201A-602): Salmonid Spawning, Rearing, and Migration; Primary Contact
Recreation; Domestic, Industrial, and Agricultural Water Supply; Stock Watering;
Wildlife Habitat; Harvesting; Commerce and Navigation; Boating; and Aesthetic
Values
B. RECEIVING WATER QUALITY
The portion of North Fork Rock Creek where the facility discharges is understood to
be an intermittent stream, meaning its flow in late summer months is nearly zero.
There are no USGS or other stream gauges in this portion of the stream, so the
facility's Surface Water Monitoring Report data are displayed in Table 4.
Table 4. Surface Water Monitoring Report
Surface Water Monitoring
Date
Flow
(gallons/day)
PH
Temp.
°F
Temp.
°C
Total
Ammonia
(mg/L)
Total
Phosphorus
(mg/L)
Nitrate
+ Nitrite
(mg/L)
TKN
(mg/L)
Dissolved
Oxygen
(mg/L)
2/17/2016
5,000
6.9
42.6
5.9
ND
0.096
1.36
0.525
12.6
4/19/2016
3,000
6.8
51.0
10.6
0.122
0.132
ND2
0.611
10.8
5/11/2016
1,500
7.2
51.2
10.7
0.096
0.104
ND2
0.792
9.7
3/22/2017
5,200
6.8
39.3
4.1
ND1
0.126
ND2
0.613
12.2
4/5/2017
3,000
6.9
44.0
6.7
ND1
0.105
ND2
0.99
10.6
3/20/2018
3,200
7.0
43.5
6.4
0.075
0.120
0.92
0.475
11.8
4/4/2018
3,000
6.8
46.6
8.1
0.155
0.091
0.38
0.584
10.8
5/2/2018
2,500
6.9
52.5
11.4
0.130
0.143
0.21
0.635
10.2
4/10/2019
3,200
7.3
53.5
11.9
0.115
0.160
1.15
0.649
11.7
4/21/2020
3,500
6.9
51.0
10.6
ND1
0.067
ND2
0.448
10.6
Average
3,310
7.0
47.5
8.6
0.116
0.114
0.80
0.632
11.1
Minimum
1,500
6.8
39.3
4.1
0.075
0.067
0.21
0.448
9.7
Maximum
5,200
7.3
53.5
11.9
0.155
0.160
1.36
0.990
12.6
1. Any total ammonia sample below the detection limit of 0.05 mg/L is labeled as non-detect (ND)
2. Any total nitrate+nitrite sample below the detection limit of 0.1 mg/L is labeled as non-detect (ND)
1. Water Quality Limited Waters
Washington Waters (downstream)
The portion of North Fork Rock Creek where the facility discharges is not listed as
water quality limited, although downstream waters from the confluence with South
Fork Rock Creek to Rockford, WA, are listed as impaired for temperature, fecal
coliform bacteria, and turbidity by the State of Washington's 2018 Water Quality
Assessment (CWA § 303(d)). Washington Department of Ecology (Ecology)
completed a TMDL for bacteria, temperature, and turbidity for the Hangman Creek
Watershed entitled Hangman (Latah) Creek Watershed Fecal Coliform Bacteria,
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Temperature, and Turbidity Total Maximum Daily Load Water Quality Implementation
Plan (Ecology, 2011) (Hangman Creek TMDL). The Hangman Creek TMDL does not
provide WLAs for point sources on the Reservation. Ecology's 2018 Hangman Creek
Watershed Nutrients and Sediment Pollutant Source Assessment lists North Fork
Rock Creek as a contributor to downstream sediment and nutrient issues, namely for
dissolved inorganic nitrogen and suspended sediment loading; however, Ecology
noted that Hangman Creek point source contributions in Washington, tend to be
localized (i.e. less than 3 miles from the point source).1 Because of the distance
between the Worley WWTP's outfall and the Hangman Creek impairment, this facility
does not appear to be a significant contributor to the downstream impairment.
Dissolved oxygen and pH impairments are typically the result of eutrophication
caused excess nutrients such as nitrogen and phosphorus leading to phytoplankton
blooms. The Spokane River and Lake Spokane Dissolved Oxygen TMDL (Ecology,
February 2010) (Spokane River TMDL) established phosphorus load allocations at
the mouth of Hangman Creek, but it did not allocate loading to sources within the
Hangman Creek watershed.
The following is a link to the Ecology webpage for the Hangman Creek subbasin:
http://www.ecv.wa.gov/programs/wq/tmdl/HangmanCr/index.html
Coeur d'Alene Reservation Waters
The WWTP discharges into Reservation Waters for which the Coeur d'Alene Tribe
does not have TAS for CWA purposes. North Fork Rock Creek has not been
evaluated for compliance with water quality standards.
As discussed above, approximately ten river miles downstream of the discharge in
Washington, North Fork Rock Creek is listed as impaired for temperature, bacteria,
and turbidity. Consequently, this draft permit proposes monitoring and effluent limits
that are protective of Washington WQS and is consistent with the recommendations in
the Hangman Creek TMDL. Since tribal designated uses are similar to those in
Washington, the Washington WQS are protective of tribal designated uses
2. Low Flow Conditions
For North Fork Rock Creek, no data on stream flow were available and the stream is
dry for at least a portion of the year as confirmed through aerial photography. A
mixing zone is not included in this permit because there is no flow during the critical
period.
The previous permit included a dilution ratio requirement which states that the facility
may only discharge when the effluent is no more than 1/10 the receiving water's
stream flow. Because of this, the facility was only able to discharge a few times per
year, and during those discharges would routinely exceed the design flow of the
facility resulting in the facility violating the effluent limits in the permit. To address this,
the dilution ratio has been replaced with end-of-pipe limits, which are more stringent,
but also allow the facility to discharge with less likelihood of exceeding permitted flow
1 Personal communication, Mitch Redfern, Ecology September 6, 2022
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limitations.
IV. Effluent Limitations and Monitoring
Table 5, below, presents the existing effluent limits and monitoring requirements in the
previous permit.
Table 5. Existing Permit - Effluent Limits and Monitoring Requirements
Parameter
Units
Effluent Limitations
Monitoring Requirements
Average
Monthly
Average
Weekly
Maximum
Daily
Sample
Location
Sample
Frequency
Sample
Type
Parameters with Effluent Limits
Biochemical Oxygen
Demand (BODs)
mg/L
30
45
-
Effluent
2/month
Grab
lbs/day
14.3
21.4
-
Calculation1
BODs Percent
Removal
%
85 (min)
-
-
-
1/mo nth
Calculation2
Total Suspended
Solids (TSS)
mg/L
30
45
-
Effluent
2/month
Grab
lbs/day
14.3
21.4
-
Calculation
TSS Percent
Removal
%
85 (min)
-
-
-
1/mo nth
Calculation2
E. coli Bacteria
CFU/
100 ml
1263
-
235
(instant
maximum)
Effluent
5/month5
Grab
PH
Std units
6.5-8.5
Effluent
1/week
Grab
Total Residual
Chlorine (TRC)4
mg/L
0.011
-
0.013
Effluent
1/week
Grab
lbs/day
0.0050
-
0.0060
Calculation
Ammonia
mg /L
4.1
-
10.6
Effluent
2/month
Grab
lbs/day
1.9
-
5.1
Calculation
Effluent Dilution
Ratio
-
A 10:1 dilution ratio is required
-
Each day of
discharge
Calculation
Narrative
See Paragraph 1.1.4 of this permit
-
Effluent
1/mo nth
Visual
Observation
Report Parameters
Flow
mgd
-
-
-
Effluent
continuous
Recording
Temperature
°C
-
-
-
Effluent
1/week
Grab
Total Phosphorus
as P
mg/L
-
-
-
Effluent
1/mo nth
Grab
Nitrate plus Nitrite
mg/L
-
-
-
Effluent
1/mo nth
Grab
Total Kjeldahl
Nitrogen
mg/L
-
-
-
Effluent
1/mo nth
Grab
Dissolved Oxygen
mg/L
-
-
-
Effluent
1/mo nth
Grab
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1. Loading (in lbs/day) is calculated by multiplying the concentration (in mg/L) by the corresponding flow (in mgd) for
the day of sampling and a conversion factor of 8.34. For more information on calculating, averaging, and reporting
loads and concentrations see the NPDES Self-Monitoring System User Guide (EPA 833-B-85-100, March 1985).
2. Percent Removal. The monthly average percent removal must be calculated from the arithmetic mean of the
influent values and the arithmetic mean of the effluent values for that month using the following equation:
(average monthly influent concentration - average monthly effluent concentration) average monthly influent
concentration x 100. Influent and effluent samples must be taken over approximately the same time period
3. The permittee must report the geometric mean E. coli concentration.
4. The limits for chlorine are not quantifiable using EPA-approved analytical methods. The minimum level (ML) for
chlorine is 50 |jg/L for this parameter. The EPA will use 50 |jg/L as the compliance evaluation level for this
parameter. The permittee will be compliance with the total residual chlorine limitations if the average monthly and
maximum daily concentration limits are less than 50 |jg/L and the average monthly and maximum daily mass
discharge limits are less than 0.024 lbs/day. For purposes of calculating the monthly averages, see Paragraph
I.B.8 of this permit.
Table 6. Draft Permit - Effluent Limits and Monitoring Requirements
The following effluent limitations are proposed in the draft permit:
Parameter
Units
Effluent Limitations
Monitoring Requirements
Average
Monthly
Average
Weekly
Maximum
Daily
Sample
Location
Sample
Frequency
Sample
Type
Parameters with Effluent Limits
Biochemical Oxygen
Demand (BODs)
mg/L
30
45
-
Influent and
Effluent
2/month
Grab
lbs/day
14.3
21.4
-
Calculation1
BODs Percent
Removal
%
85 (min)
-
-
-
1/month
Calculation2
Total Suspended
Solids (TSS)
mg/L
30
45
-
Influent and
Effluent
2/month
Grab
lbs/day
14.3
21.4
-
Calculation
TSS Percent
Removal
%
85 (min)
-
-
-
1/month
Calculation2
E. Coli Bacteria
CFU/
100 ml
1003
-
235
(instant
maximum)
Effluent
5/month5
Grab
PH
Std units
6.5-8.5
Effluent
1/week
Grab
Total Residual
Chlorine (TRC)4
mg/L
0.009
-
0.018
Effluent
1/week
Grab
lbs/day
0.0043
-
0.009
Calculation
Ammonia
mg/L
4.1
-
10.6
Effluent
2/month
Grab
lbs/day
1.9
-
5.1
Calculation
Narrative
See Paragraph 1.2 of this permit
-
Effluent
1/month
Visual
Observation
Report Parameters
Flow
mgd
-
-
-
Effluent
Continuous
Recording
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Parameter
Units
Effluent Limitations
Monitoring Requirements
Average
Monthly
Average
Weekly
Maximum
Daily
Sample
Location
Sample
Frequency
Sample
Type
Temperature
°C
-
-
-
Effluent
1/week or
Continuous5
Grab
Total Phosphorus
as P
mg/L
-
-
-
Effluent
1/month
Grab
Nitrate plus Nitrite
mg/L
-
-
-
Effluent
1/month
Grab
Total Kjeldahl
Nitrogen
mg/L
-
-
-
Effluent
1/month
Grab
Dissolved Oxygen
mg/L
-
-
-
Effluent
1/month
Grab
Per- and
Polyfluoroalkyl
Substances (PFAS)6
ng/L
Report
-
Report
Influent and
Effluent
1/quarter6
24-Hour
Composite
mg/kg
dry
weight
-
-
Report
Sludge
1/quarter6
Grab
1. Loading (in lbs/day) is calculated by multiplying the concentration (in mg/L) by the corresponding flow (in mgd) for
the day of sampling and a conversion factor of 8.34. For more information on calculating, averaging, and
reporting loads and concentrations see the NPDES Self-Monitoring System User Guide (EPA 833-B-85-100,
March 1985).
2. Percent Removal. The monthly average percent removal must be calculated from the arithmetic mean of the
influent values and the arithmetic mean of the effluent values for that month using the following equation:
(average monthly influent concentration - average monthly effluent concentration) average monthly influent
concentration x 100. Influent and effluent samples must be taken over approximately the same time period
3. The permittee must report the geometric mean E. coli concentration.
4. The limits for chlorine are not quantifiable using EPA-approved analytical methods. The minimum level (ML) for
chlorine is 50 |jg/L for this parameter. The EPA will use 50 |jg/L as the compliance evaluation level for this
parameter. The permittee will be compliance with the total residual chlorine limitations if the average monthly and
maximum daily concentration limits are less than 50 |jg/L and the average monthly and maximum daily mass
discharge limits are less than 0.024 lbs/day. For purposes of calculating the monthly averages, see Paragraph
I.B.8 of this permit.
5. The permittee must monitor influent and effluent temperature one per week from the effective date of the permit
to (insert four years). Starting (first day of the fifth year of the effective date of the permit) the permittee must
monitor temperature continuously.
6. Monitoring for PFAS chemicals is required for 2 years (8 quarters), beginning at the start of the first complete
quarter in the third year of the permit term.
7. See Permit Part I.B.8.
Effluent Limitation Changes
The previous permit required a 10:1 dilution ratio, which was removed for this
permit. Because North Fork Rock Creek is ephemeral and runs dry periodically,
this dilution ratio requirement restricted the facility to only discharge a few times a
year which resulted in the facility exceeding its design flow and, thus, exceeding
the calculated effluent limits. The new permit maintains the temporal limitation of
discharge only being allowed between November 1 and June 30; however, the
permit no longer contains the dilution ratio and, instead, contains end-of-pipe limits.
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The average monthly effluent limit for the E. coli was decreased to a geometric
mean of 100 CFU/100 ml_ to reflect an amendment made to the Washington Water
Quality Standards Chapter 173-201A on January 23, 2019. This is a more stringent
effluent limit than the previous effluent limit of 126 CFU/100 ml_.
EPA recalculated the total residual chlorine effluent limits using the recent effluent
data which showed a higher variability compared with the data used to calculate
the limits in the current (2015) permit. This resulted in less stringent maximum daily
limits but more stringent average monthly limits. See below for anti-backsliding
discussion for the limits that are less stringent.
A. BASIS FOR EFFLUENT LIMITS
In general, the CWA requires that the effluent limits for a particular pollutant be the
more stringent of either technology-based effluent limits (TBELs) or WQBELs. TBELs
are set according to the level of treatment that is achievable using available
technology. A WQBEL is designed to ensure that the WQS applicable to a waterbody
are being met and may be more stringent than TBELs.
1. Pollutants of Concern
Pollutants of concern are those that either have TBELs or may need WQBELs.
EPA identifies pollutants of concern for the discharge based on those which:
Have a technology-based limit
Have an assigned wasteload allocation (WLA) from a TMDL
Had an effluent limit in the previous permit
Are present in the effluent monitoring. Monitoring data are reported in the
application and DMR and any special studies
Are expected to be in the discharge based on the nature of the discharge
The wastewater treatment process for this facility includes both primary and
secondary treatment, as well as disinfection with chlorination. Pollutants expected
in the discharge from a facility with this type of treatment, include but are not
limited to: five-day biochemical oxygen demand (BODs), total suspended solids
(TSS), E. coli bacteria, total residual chlorine (TRC), pH, ammonia, temperature,
phosphorus, and dissolved oxygen (DO).
Based on this analysis, pollutants of concern are as follows:
BODs
DO
TSS
E. coli bacteria
TRC
pH
Ammonia
Total Kjeldahl Nitrogen
Nitrate-Nitrite
Phosphorus
Temperature
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Per- and polyfluoroalkyl substances (PFAS)
2. Technology-Based Effluent Limits (TBELs)
a. Federal Secondary Treatment Effluent Limits
The CWA requires POTWs to meet performance-based requirements based
on available wastewater treatment technology. CWA § 301 established a
required performance level, referred to as "secondary treatment," which
POTWs were required to meet by July 1, 1977. EPA has developed and
promulgated "secondary treatment" effluent limitations, which are found in 40
CFR 133.102. These TBELs apply to certain municipal WWTPs and identify
the minimum level of effluent quality attainable by application of secondary
treatment in terms of BODs, TSS, and pH. The federally promulgated
secondary treatment effluent limits are listed in Table 7. For additional
information and background refer to Part 5.1 Technology Based Effluent
Limits for POTWs in the Permit Writers Manual.
Table 7. Secondary Treatment Effluent Limits
Parameter
30-day average
7-day average
BODs
30 mg/L
45 mg/L
TSS
30 mg/L
45 mg/L
Removal for BODs and
TSS (concentration)
85% (minimum)
--
PH
within the limits of 6.0 - 9.0 s.u.
Source: 40 CFR 133.102
b. Equivalent to Secondary Treatment Effluent Limits
EPA has additionally established effluent limitations (40 CFR 133.105) that
are considered "equivalent to secondary treatment" which apply to facilities
meeting certain conditions established under 40 CFR 133.101(g). The
federally promulgated equivalent to secondary treatment effluent limits are
listed below in Table 8.
Table 8. Equivalent to Secondary Treatment Effluent Limits
Parameter
30-day average
7-day average
BODs
45 mg/L
65 mg/L
TSS
45 mg/L
65 mg/L
Removal for BODs and
TSS (concentration)
65% (minimum)
--
Source: 40 CFR 133.105
Using DMR data from November 2016 to May 2021, EPA evaluated the
facility's eligibility for effluent limits based on equivalent to secondary
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treatment standards. To be eligible, a POTW must meet all three of the
following criteria:
Criterion #1 - Consistently Exceeds Secondary Treatment Standards: The
first criterion that must be satisfied to qualify for the equivalent to secondary
standards is demonstrating that the BODs and TSS effluent concentrations
consistently achievable through proper operation and maintenance of the
treatment works exceed the secondary treatment standards set forth in 40
CFR 133.102(a) and (b). 40 CFR 133.101(f) defines "effluent concentrations
consistently achievable through proper operation and maintenance" as
¦ (f)(1): For a given pollutant parameter, the 95th percentile value for the
30-day average effluent quality achieved by a treatment works in a
period of at least 2 years, excluding values attributable to upsets,
bypasses, operational errors, or other unusual conditions, and
¦ (f)(2): A 7-day average value equal to 1.5 times the value derived under
paragraph (f)(1)
Criterion #2 - Principal Treatment Process: The second criterion that a facility
must meet to be eligible for equivalent to secondary standards is that its
principal treatment process must be a trickling filter or waste stabilization
pond (i.e., the largest percentage of BODs and TSS removal is from a trickling
filter or waste stabilization pond system).
Criterion #3 - Provide Significant Biological Treatment: The third criterion for
applying equivalent to secondary standards is that the treatment works
provides significant biological treatment of municipal wastewater. 40 CFR
133.101 (k) defines significant biological treatment as using an aerobic or
anaerobic biological treatment process in a treatment works to consistently
achieve a 30-day average of at least 65 percent removal of BODs.
EPA determined that the facility does not meet all three criteria, therefore, is
not eligible for equivalent to secondary treatment standards.
See Table 9 for the Treatment Equivalent to Secondary Treatment determinations for
BOD5 and TSS.
Table 9. Treatment Equivalent to Secondary Treatment Determinations for BODs and
TSS
Criterion 1: Consistently Exceeds Secondary Treatment Standards
BODs
95th Percentile
Secondary Treatment
Standard
Exceeds
Secondary
Standard
Average
Monthly
13.0 mg/L
30 mg/L
No
Weekly
Average
13.0 mg/L x 1.5= 19.5
mg/L
45 mg/L
No
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TSS
95th Percentile
Secondary Treatment
Standard
Exceeds
Secondary
Standard
Average
Monthly
20.1 mg/L
30 mg/L
No
Weekly
Average
20.1 mg/L x 1.5 = 30.2
mg/L
45 mg/L
No
Criterion 2: Principal Treatment Process
Waste stabilization ponds are the primary treatment method; this meets
Criterion 2.
Table 10. Significant Biological Treatment
Criterion 3: Provides Significant Biological Treatment
BODs 30-day
Average Percent
Removal
5th Percentile
Treatment
Standard
Provides Significant
Biological Treatment
89.4%
65%
Yes
The POTW does not meet the three criteria for treatment equivalent to
secondary for BODs, therefore the technology-based secondary limits, for
BOD5, apply.
The POTW does not meet the three criteria for treatment equivalent to
secondary for TSS, therefore the technology-based secondary limits, for
TSS, apply.
Table 11 lists the basis and proposed effluent limits for BODs and TSS.
Table 11. Effluent Limits for BODs and TSS
Parameter
Monthly
Average
Weekly
Average
Percent
Removal
Basis
BODs
30 mg/L
45 mg/L
85%
TBELs for secondary treatment
(40 CFR 133.102(a)-(b))
TSS
30 mg/L
45 mg/L
85%
TBELs for secondary treatment
(40 CFR 133.102(a)-(b))
c. Mass-Based Limits
40 CFR 122.45(f) requires that effluent limits be expressed in terms of mass,
except under certain conditions. 40 CFR 122.45(b) requires that effluent
limitations for POTWs be calculated based on the design flow of the facility.
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The mass based limits are expressed in pounds per day and are calculated
as follows:
Mass based limit = concentration limit (mg/L) * design flow (mgd) * 8.342
Since the design flow for this facility is 0.0571 mgd, the technology-based
mass limits for BODs and TSS are calculated as follows:
Average Monthly Limit = 30 mg/L * 0.0571 mgd * 8.34 = 14.3 lbs/day
Average Weekly Limit = 45 mg/L * 0.0571 mgd * 8.34 = 21.4 lbs/day
3. Chlorine
Chlorine is often used to disinfect municipal wastewater prior to discharge. The
City of Worley WWTP uses chlorine disinfection. A 0.5 mg/L average monthly limit
for chlorine is derived from standard operating practices. The Water Pollution
Control Federation's Chlorination of Wastewater (1976) states that a properly
designed and maintained wastewater treatment plant can achieve adequate
disinfection if a 0.5 mg/L chlorine residual is maintained after 15 minutes of
contact time. Therefore, a wastewater treatment plant that provides adequate
chlorine contact time can meet a 0.5 mg/L total residual chlorine limit on a
monthly average basis. In addition to average monthly limits (AMLs), NPDES
regulations require effluent limits for POTWs to be expressed as average weekly
limits (AWLs) unless impracticable. For TBELs, the AWL is calculated to be 1.5
times the AML, consistent with the "secondary treatment" limits for BODs and
TSS. This results in an AWL for chlorine of 0.75 mg/L.
4. Water Quality-Based Effluent Limits (WQBELs)
a. Statutory and Regulatory Basis
CWA § 301(b)(1)(C) requires the development of limitations in permits
necessary to meet WQS. Discharges to State or Tribal waters must also
comply with conditions imposed by the State or Tribe as part of its certification
of NPDES permits under CWA § 401. 40 CFR 122.44(d)(1) implementing
CWA § 301 (b)(1 )(C) requires that permits include limits for all pollutants or
parameters which are or may be discharged at a level which will cause, have
the reasonable potential to cause, or contribute to an excursion above any
State or Tribal WQS, including narrative criteria for water quality. Effluent
limits must also meet the applicable water quality requirements of affected
States other than the State in which the discharge originates, which may
include downstream States (40 CFR 122.4(d), 122.44(d)(4), see also CWA §
401(a)(2)).
The regulations require the permitting authority to make this evaluation using
procedures which account for existing controls on point and nonpoint sources
of pollution, the variability of the pollutant in the effluent, species sensitivity
(for toxicity), and where appropriate, dilution in the receiving water. The limits
must be stringent enough to ensure that WQS are met and must be
2 8.34 is a conversion factor with units (lb xL)/(mg * gallonxlO6)
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consistent with any available wasteload allocation for the discharge in an
approved TMDL. If there are no approved TMDLs that specify wasteload
allocations for this discharge; all of the WQBELs are calculated directly from
the applicable WQS.
b. Reasonable Potential Analysis and Need for WQBELs
EPA uses the process described in the Technical Support Document for
Water Quality-based Toxics Control (TSD) to determine reasonable potential.
To determine if there is reasonable potential for the discharge to cause or
contribute to an exceedance of water quality criteria for a given pollutant, EPA
compares the maximum projected receiving water concentration to the water
quality criteria for that pollutant. If the projected receiving water concentration
exceeds the criteria, there is reasonable potential, and a WQBEL must be
included in the permit.
The equations used to conduct the reasonable potential analysis and
calculate the WQBELs are provided in Appendices C and D.
c. Reasonable Potential and WQBELs
The reasonable potential analysis and WQBEL for specific parameters are
summarized below. The calculations are provided in Appendix D.
Ammonia
Ammonia criteria are based on a formula which relies on the pH and
temperature of the receiving water, because the fraction of ammonia present
as the toxic, un-ionized form increases with increasing pH and temperature.
Therefore, the criteria become more stringent as pH and temperature
increase. Table 12, below, details the equations used to determine water
quality criteria for ammonia.
Table 12. Ammonia Criteria
Total ammonia nitrogen criteria (mg N/L):
Annual Basis
Based on IDAPA 58.01.02
INPUT
Acute Criteria Equation: Cold Water
1. Receiving Water Temperature (deg C):
11.7
2. Receiving Water pH:
7.26
3. Is the receiving water a cold water designated use?
Yes
Acute Criteria Equation: Warm Water CMC =
4. Are non-salmonid early life stages present or absent?
Present
OUTPUT
Total ammonia nitrogen criteria (mg N/L):
Acute Criterion (CMC)
18.39
Chronic Criteria: Cold Water, Early Life Stages Present
Chronic Criterion (CCC)
5.21
CMC
0.275
39 .0
I + 10 1 + 10 "**
0 .41 ] 58 .4
2,487 )i
l+io-"-""
W/iV(2.85.1.45 10"
Chronic Criteria: Cold Water, Early Life Stages Absent
«r.f 00577 + 1487 1.1.45 10"--
U+llO'-'" 1 + 10*-'- J
A reasonable potential calculation showed that the City of Worley WWTP
discharge would have the reasonable potential to cause or contribute to a
violation of the water quality criteria for ammonia. However, the previous
permit included WQBELs for ammonia which are more stringent than the
ones that were for this permit. To comply with antibacksliding, the draft
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permit maintains these ammonia limits from the previous permit. The draft
permit requires that the permittee monitor the receiving water for ammonia,
pH and temperature in order to determine the applicable ammonia criteria for
the next permit reissuance. See Appendices C and D for reasonable potential
and effluent limit calculations for ammonia.
jdH
The Washington WQS at WAC 173-201 A-200(g), require pH values of the
receiving water to be within the range of 6.5 to 8.5. Mixing zones are
generally not granted for pH, therefore, the most stringent water quality
criterion must be met before the effluent is discharged to the receiving water.
Effluent pH data were compared to the water quality criteria. The pH data in
the effluent have ranged between 6.9 and 8.0 over the last five years.
Dissolved Oxygen (DO) and BODs
The impaired portion of the downstream receiving water is listed under
Ecology's Aquatic Life Designated Uses for salmonid spawning, rearing, and
migration, which requires a DO one-day minimum requirement of 8.0 mg/L.
WAC 173-201 A-200(1)(d). Natural decomposition of organic material in
wastewater effluent impacts dissolved oxygen in the receiving water at
distances far outside of the regulated mixing zone. The BODs of an effluent
sample indicates the amount of biodegradable material in the wastewater and
estimates the magnitude of oxygen consumption the wastewater will generate
in the receiving water. It is assumed that the BODsTBEL will be stringent
enough to protect DO downstream. Effluent monitoring of DO is required in
this permit.
Phosphorus, Total Kieldahl Nitrogen, and Nitrate-Nitrite
Because of the facility's low discharge and with a mean monthly maximum
total phosphorus concentration of 2.3 mg/L, EPA does not believe there is
reasonable potential for the discharge to exceed any applicable water quality
standards. However, Hangman Creek is impaired for dissolved oxygen upon
entering Washington, which can be caused or exacerbated by phosphorus
and nitrogenous compounds caused by phytoplankton. Therefore, the
permitee is required to monitor effluent for total phosphorus (as P), nitrate-
nitrite, and total kjeldahl nitrogen once per month to ensure the nutrient
concentrations are not increasing.
E. coli
The Washington WQS state that waters of the State of Washington, that are
designated for recreation, limit discharge to a geometric mean value of 100
CFU or MPN per 100 mL during an averaging period, with not more than 10
percent of all samples (or any single sample when less than ten sample
points exist) obtained within the averaging period exceeding 320 CFU or MPN
per 100 mL (WAC 173-201 A-200(2)(b)). The previous permit used Coeur
d'Alene Tribal WQS for E. coli, which include a geometric mean of 126 CFU
or MPN per 100 mL during an averaging period, and an instantaneous
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maximum of 235 CFU or MPN per 100 ml_. The draft permit uses the
Washington WQS value for the geometric mean, and preserves the value for
the instantaneous maximum from the previous permit in order to comply with
antibacksliding.
The goal of a WQBEL is to ensure a low probability that WQS will be
exceeded in the receiving water as a result of a discharge, while considering
the variability of the pollutant in the effluent. EPA imposed an instantaneous
(single grab sample) maximum effluent limit for E. coli of 235 organisms per
100 ml, in addition to a monthly geometric mean limit of 100 organisms per
100 ml, which directly implements the water quality criterion for E. coli. This
will ensure that the discharge will have a low probability of exceeding WQS
for E. coli.
40 CFR 122.45(d)(2) requires that effluent limitations for continuous
discharges from POTWs be expressed as average monthly and average
weekly limits, unless impracticable. Additionally, the terms "average monthly
limit" and "average weekly limit" are defined in 40 CFR 122.2 as being
arithmetic (as opposed to geometric) averages. It is impracticable to properly
implement a 30-day geometric mean criterion in a permit using monthly and
weekly arithmetic average limits. The geometric mean of a given data set is
equal to the arithmetic mean of that data set if and only if all of the values in
that data set are equal. Otherwise, the geometric mean is always less than
the arithmetic mean. In order to ensure that the effluent limits are "derived
from and comply with" the geometric mean water quality criterion, as required
by 40 CFR 122.44(d)(1)(vii)(A), it is necessary to express the effluent limits as
a monthly geometric mean and an instantaneous maximum limit.
Temperature
The Washington water quality standards at WAC 173-201 A-200(1)(c)
establish criterion for the protection of salmonid spawning, which is the
designated use downstream of the discharge in Hangman Creek (See
Section III.A.1 of the Fact Sheet). Because this downstream segment is
impaired for temperature, as described in the Hangman Creek TMDL,
temperature is a pollutant of concern. While the current permit includes
temperature monitoring in the receiving water and effluent, there are only
eight temperature samples in the last five years from the facility; therefore to
properly understand the potential for the facility to exceed temperature
criteria, this permit is proposing more frequent temperature monitoring via
weekly grab sampling for the first four years of this permit, followed by
continuous grab sampling beginning the fifth year of the permit.
Chlorine
The WQS at WAC 173-201A-240 (Table 240) establish an acute criterion of
19 |jg/L, and a chronic criterion of 11 |jg/L for the protection of aquatic life. A
reasonable potential calculation indicated the discharge from the facility would
have the reasonable potential to cause or contribute to a violation of the water
quality criteria for chlorine. EPA recalculated the effluent limits using the
recent effluent data which showed a higher variability compared with the data
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used to calculate the limits in the current (2015) permit. Both the existing and
draft limits meet the water quality standards at the point of discharge,
therefore the draft limits are as stringent as the previous permit's limits. These
are more stringent than chlorine TBELs, and therefore, the proposed chlorine
limits are WQBELs.
Residues
The Washington WQS require that surface waters of the State be free from
floating, suspended or submerged matter of any kind in concentrations
impairing designated beneficial uses. The draft permit contains a narrative
limitation prohibiting the discharge of such materials.
Narrative Requirements
The Washington WQS require that surface waters be free from floating,
suspended or submerged matter of any kind in concentrations impairing
designated beneficial uses. The Coeur d'Alene Reservation WQS have
similar requirements. The draft permit contains a narrative limitation
prohibiting the discharge of such materials.
The Washington WQS have general water quality criteria, EPA has included a
narrative limitation prohibiting the discharge of visible oils, scum, foam,
grease, and other floating materials and suspended substances of a
persistent nature that may impair designated uses. The permittee must
visually inspect the effluent for these conditions once per month.
d. Antibacksliding
CWA § 402(o) and 40 CFR 122.44(1) generally prohibit the renewal,
reissuance or modification of an existing NPDES permit that contains effluent
limits, permit conditions or standards that are less stringent than those
established in the previous permit (i.e., anti-backsliding) but provides limited
exceptions. For explanation of the antibacksliding exceptions refer to Chapter
7 of the Permit Writers Manual Final Effluent Limitations and Anti-backsliding.
The draft permit does not backslide. The draft permit retains the previous
(more stringent) ammonia limits. The chlorine limits meet the water criteria at
the end of pipe.
B. Monitoring Requirements
CWA § 308 and federal regulation 40 CFR 122.44(i) require monitoring in permits to
determine compliance with effluent limitations. Monitoring may also be required to
gather effluent and surface water data to determine if additional effluent limitations are
required and/or to monitor effluent impacts on receiving water quality.
The permit also requires the permittee to perform effluent monitoring required by the
NPDES Form 2A application, so that these data will be available when the permittee
applies for a renewal of its NPDES permit.
The permit also requires the permittee to perform effluent monitoring required by
Tables A and B the NPDES Form 2A application, so that these data will be available
when the permittee applies for a renewal of its NPDES permit.
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant Page 25 of 52
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The permittee is responsible for conducting the monitoring and for reporting results on
DMRs or on the application for renewal, as appropriate, to EPA.
1. Effluent Monitoring
Monitoring frequencies are based on the nature and effect of the pollutant, as well
as a determination of the minimum sampling necessary to adequately monitor the
facility's performance. Permittees have the option of taking more frequent
samples than are required under the permit. These samples must be used for
averaging if they are conducted using EPA-approved test methods (generally
found in 40 CFR 136) or as specified in the permit.
Dilution Ratio
Because the draft permit proposes more stringent end-of-pipe limits, described in
Section III.A.3, the dilution ratio effluent limit was removed, therefore the draft
permit no longer requires reporting of the effluent dilution ratio.
Per- and polvfluoroalkvl substances (PFAS)
PFAS are a group of synthetic chemicals that have been in use since the 1940s.
PFAS are found in a wide array of consumer and industrial products. Due to their
widespread use and persistence in the environment, most people in the United
States have been exposed to PFAS. Discharges of PFAS above certain levels
may cause adverse effects to human health effects or aquatic life.3 4
Since PFAS chemicals are persistent in the environment and may lead to adverse
human health and environmental effects, the draft permit requires that the
permittee conduct quarterly influent, effluent, and sludge sampling for PFAS
chemicals for two years. The monitoring requirements for PFAS chemicals are
deferred until the third and fourth years of the permit term (beginning during the
first complete quarter5 of the third year). This will give the permittee time to plan
for this new monitoring requirement (e.g., to obtain funding, train employees, and
find a suitable contract laboratory).
The purpose of these monitoring and reporting requirements is to better
understand potential discharges of PFAS from this facility and to inform future
permitting decisions, including the potential development of water quality-based
effluent limits. EPA is authorized to require this monitoring and reporting by CWA
§ 308(a). The permit conditions reflect EPA's commitments in the PFAS Strategic
3 EPA, EPA's Per- and Polyfluoroalkyl Substances (PFAS) Action Plan, EPA 823R18004, February 2019.
Available at: https://www.epa.qov/sites/production/files/2019-
02/documents/pfas action plan 021319 508compliant 1.pdf
4 EPA, Fact Sheet: Draft 2022 Aquatic Life Ambient Water Quality Criteria for Perfluorooctanoic acid (PFOA)
and Perfluorooctane Sulfonic Acid (PFOS). Available at:
https://www.epa.qov/svstem/files/documents/2022-04/pfoa-pfos-draft-factsheet-2022.pdf
5 Quarters are defined as: January 1 to March 31; April 1 to June 30; July 1 to September 30; and October 1
to December 31.
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant Page 26 of 52
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Roadmap, which directs the Office of Water to leverage NPDES permits to reduce
PFAS discharges to waterways "at the source and obtain more comprehensive
information through monitoring on the sources of PFAS and quantity of PFAS
discharged by these sources."
EPA notes that there is currently not an analytical method approved in 40 CFR
Part 136 for PFAS. As stated in 40 CFR 122.44(i)(1)(iv)(B), in the case of
pollutants or pollutant parameters for which there are no approved methods under
40 CFR Part 136 or methods are not otherwise required under 40 CFR chapter I,
subchapter N or 0, monitoring shall be conducted according to a test procedure
specified in the permit for such pollutants or pollutant parameters. Therefore, the
Permit specifies that until there is an analytical method approved in 40 CFR Part
136 for PFAS, monitoring shall be conducted using Draft Method 1633.
2. Surface Water Monitoring
In general, surface water monitoring may be required for pollutants of concern to
assess the assimilative capacity of the receiving water for the pollutant. In
addition, surface water monitoring may be required for pollutants for which the
water quality criteria are dependent and to collect data for TMDL development if
the facility discharges to an impaired water body. Table 13 presents the proposed
surface water monitoring requirements for the draft permit. Surface water
monitoring results must be submitted with the DMR.
Table 13. Surface Water Monitoring in Draft Permit1
Parameter
Units
Sample Location
Sample Type
Sample
Frequency
Flow
mgd
Upstream of WWTP outfall
Recordings
Daily2
PH
s.u.
Upstream of WWTP outfall
Grab
1/mo nth
Temperature
°C
Upstream of WWTP outfall
Grab
1/week or
Continuous3
Total Ammonia as N
mg/L
Upstream of WWTP outfall
Grab
1/mo nth
Total Phosphorus as P
mg/L
Upstream of WWTP outfall
Grab
1/mo nth
Nitrate plus Nitrite
mg/L
Upstream of WWTP outfall
Grab
1/mo nth
Total Kjeldahl Nitrogen
mg/L
Upstream of WWTP outfall
Grab
1/mo nth
Dissolved Oxygen
mg/L
Upstream of WWTP outfall
Grab
1/mo nth
1 - Monitoring must be conducted underflow conditions typical for the month when sampling occurs. Samples
should not be collected immediately after storm events.
2 - Permittee shall provide an estimate or measurement of flow for each day when discharge occurs.
3 - Permittee must monitor receiving water temperature once per week from the effective date of the permit to
(insert four years). Starting (first day of the fifth year of the effective date of the permit) the permittee must
monitor temperature continuously.
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3. Electronic Submission of Discharge Monitoring Reports
The draft permit requires that the permittee submit DMR data electronically using
NetDMR. NetDMR is a national web-based tool that allows DMR data to be
submitted electronically via a secure Internet application.
EPA currently conducts free training on the use of NetDMR. Further information
about NetDMR, including upcoming trainings and contacts, is provided on the
following website: https://netdmr.epa.gov.
The permittee may use NetDMR after requesting and receiving permission from
EPA Region 10. Part III.B.3 of the draft permit requires that the permittee submit a
copy of the DMR to the Coeur d'Alene Tribe. Currently, the permittee may submit
a copy to the Coeur d'Alene Tribe by one of three ways: 1. a paper copy may be
mailed. 2. The email address for the Coeur d'Alene Tribe may be added to the
electronic submittal through NetDMR, or 3. The permittee may provide the Coeur
d'Alene Tribe viewing rights through NetDMR.
C. Sludge (Biosolids) Requirements
EPA Region 10 separates wastewater and sludge permitting. EPA has authority under
the CWA to issue separate sludge-only permits for the purposes of regulating
biosolids. EPA may issue a sludge-only permit to each facility at a later date, as
appropriate.
Until future issuance of a sludge-only permit, sludge management and disposal
activities at each facility continue to be subject to the national sewage sludge
standards at 40 CFR Part 503 and any requirements of the State's biosolids program.
The Part 503 regulations are self-implementing, which means that facilities must
comply with them whether or not a permit has been issued.
V. Special Conditions
A. Nutrient Optimization Plan and Report
Permit Part II.A requires the permittee to submit a Nutrient Optimization Plan and
Report within 48 months of the effective date of the permit and identify the
optimization strategy selected for implementation within 18 months of the effective
date of the permit. The Nutrient Optimization Study must evaluate and implement
operational strategies for maximizing phosphorus removal from the existing treatment
plant during the permit term. The plan must be submitted to EPA and the Coeur
d'Alene Tribe.
B. Quality Assurance Plan
The City of Worley WWTP is required to update the Quality Assurance Plan (QAP)
within 180 days of the effective date of the permit. The QAP must consist of standard
operating procedures the permittee must follow for collecting, handling, storing and
shipping samples, laboratory analysis, and data reporting. The plan must be retained
on site and made available to EPA and the Coeur d'Alene Tribe.
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C. Operation and Maintenance Plan
The permit requires the City of Worley WWTP to properly operate and maintain all
facilities and systems of treatment and control. Proper operation and maintenance is
essential to meeting discharge limits, monitoring requirements, and all other permit
requirements at all times. The permittee is required to develop and implement an
operation and maintenance plan for their facility within 180 of the effective date of the
permit. The plan must be retained on site and made available to EPA and Coeur
d'Alene Tribe.
D. Sanitary Sewer Overflows and Proper Operation and
Maintenance of the Collection System
SSOs are not authorized under this permit. The permit contains language to address
SSO reporting and public notice and operation and maintenance of the collection
system. The permit requires that the permittee identify SSO occurrences and their
causes. In addition, the permit establishes reporting, record keeping and third party
notification of SSOs. Finally, the permit requires proper operation and maintenance of
the collection system.
The following specific permit conditions apply:
Immediate Reporting - The permittee is required to notify EPA of an SSO within 24
hours of the time the permittee becomes aware of the overflow. (See 40 CFR
122.41(l)(6))
Written Reports - The permittee is required to provide EPA a written report within
five days of the time it became aware of any overflow that is subject to the immediate
reporting provision. (See 40 CFR 122.41 (l)(6)(i)).
Third Party Notice - The permit requires that the permittee establish a process to
notify specified third parties of SSOs that may endanger health due to a likelihood of
human exposure; or unanticipated bypass and upset that exceeds any effluent
limitation in the permit or that may endanger health due to a likelihood of human
exposure. The permittee is required to develop, in consultation with appropriate
authorities at the local, county, tribal and/or state level, a plan that describes how,
under various overflow (and unanticipated bypass and upset) scenarios, the public, as
well as other entities, would be notified of overflows that may endanger health. The
plan should identify all overflows that would be reported and to whom, and the specific
information that would be reported. The plan should include a description of lines of
communication and the identities of responsible officials. (See 40 CFR 122.41 (l)(6)).
Record Keeping - The permittee is required to keep records of SSOs. The permittee
must retain the reports submitted to EPA and other appropriate reports that could
include work orders associated with investigation of system problems related to a
SSO, that describes the steps taken or planned to reduce, eliminate, and prevent
reoccurrence of the SSO. (See 40 CFR 122.41 (j)).
Proper Operation and Maintenance - The permit requires proper operation and
maintenance of the collection system. (See 40 CFR 122.41(d) and (e)). SSOs may be
indicative of improper operation and maintenance of the collection system. The
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
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permittee may consider the development and implementation of a capacity,
management, operation and maintenance (CMOM) program.
The permittee may refer to the Guide for Evaluating Capacity, Management,
Operation, and Maintenance (CMOM) Programs at Sanitary Sewer Collection
Systems (EPA 305-B-05-002). This guide identifies some of the criteria used by EPA
inspectors to evaluate a collection system's management, operation and maintenance
program activities. Owners/operators can review their own systems against the
checklist (Chapter 3) to reduce the occurrence of sewer overflows and improve or
maintain compliance.
E. Environmental Justice
As part of the permit development process, EPA Region 10 conducted a screening
analysis to determine whether this permit action could affect overburdened
communities. "Overburdened" communities can include minority, low-income, tribal,
and indigenous populations or communities that potentially experience
disproportionate environmental harms and risks. EPA used a nationally consistent
geospatial tool that contains demographic and environmental data for the United
States at the Census block group level. This tool is used to identify permits for which
enhanced outreach may be warranted.
The City of Worley WWTP is located within or near a Census block group that is
potentially overburdened because of cumulative direct discharge pollution, as well as
airborne particulate matter.
Regardless of whether a facility is located near a potentially overburdened community,
EPA encourages permittees to review (and to consider adopting, where appropriate)
Promising Practices for Permit Applicants Seeking EPA-lssued Permits: Ways To
Engage Neighboring Communities (see https://www.federalregister.goV/d/2013-
10945). Examples of promising practices include: thinking ahead about community's
characteristics and the effects of the permit on the community, engaging the right
community leaders, providing progress or status reports, inviting members of the
community for tours of the facility, providing informational materials translated into
different languages, setting up a hotline for community members to voice concerns or
request information, follow up, etc.
For more information, please visit https://www.epa.gov/environmentaliustice and
Executive Order 12898, Federal Actions to Address Environmental Justice in Minority
Populations and Low-income Populations.
F. Standard Permit Provisions
Permit Parts III., IV. and V. contain standard regulatory language that must be
included in all NPDES permits. The standard regulatory language covers requirements
such as monitoring, recording, and reporting requirements, compliance
responsibilities, and other general requirements.
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
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VI. Other Legal Requirements
A. Endangered Species Act
The Endangered Species Act requires federal agencies to consult with National
Oceanic and Atmospheric Administration Fisheries (NOAA Fisheries) and the U.S.
Fish and Wildlife Service (USFWS) if their actions could beneficially or adversely
affect any threatened or endangered species. A review of the threatened and
endangered species located in Idaho finds that there are no threatened or endangered
species present near the facility's outfall in North Fork Rock Creek. Bull trout, a
threatened salmonid species, is found near Hangman Creek approximately ten miles
downstream; however, EPA concludes that this permitting action has no effect on
endangered or threatened species under the jurisdiction of NOAA Fisheries or
USFWS due to the low flow from the facility compared to the receiving water flow from
the point of discharge to Hangman Creek from November 1 - June 30, the period of
time the permittee is allowed to discharge
B. Essential Fish Habitat
Essential fish habitat (EFH) is the waters and substrate (sediments, etc.) necessary
for fish to spawn, breed, feed, or grow to maturity. The Magnuson-Stevens Fishery
Conservation and Management Act (January 21, 1999) requires EPA to consult with
NOAA Fisheries when a proposed discharge has the potential to adversely affect EFH
(i.e., reduce quality and/or quantity of EFH). A review of the Essential Fish Habitat
documents shows that no critical habitats are present in North Fork Rock Creek.
The EFH regulations define an adverse effect as any impact which reduces quality
and/or quantity of EFH and may include direct (e.g. contamination or physical
disruption), indirect (e.g. loss of prey, reduction in species' fecundity), site specific, or
habitat-wide impacts, including individual, cumulative, or synergistic consequences of
actions. EPA has prepared an EFH assessment which appears in Appendix F.
EPA has determined that issuance of this permit will not affect EFH in North Fork
Rock Creek.
C. CWA § 401 Certification
CWA § 401 requires a Certification that any permit requirements comply with the
appropriate sections of the CWA, as well as any appropriate requirements of Tribal
Law. See 33 USC § 1341(d). Since this facility discharges to tribal waters and the
Tribe has not been approved for TAS for these waters from EPA under the CWA, EPA
is the certifying authority. EPA is taking comment on EPA's intent to certify this permit.
See the draft certification in Appendix F.
D. Antidegradation
EPA has completed an antidegradation review and finds that it is consistent with State
water quality standards and the State's antidegradation implementation procedures.
E. Permit Expiration
The permit will expire five years from the effective date.
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
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VII. References
EPA. 1991. Technical Support Document for Water Quality-based Toxics Control. US
Environmental Protection Agency, Office of Water, EPA/505/2-90-001.
https://www3.epa.gov/npdes/pubs/owm0264.pdf
Water Pollution Control Federation. Subcommittee on Chlorination of Wastewater.
Chlorination of Wastewater. Water Pollution Control Federation. Washington, D.C.
1976.
EPA. 2010. NPDES Permit Writers' Manual. Environmental Protection Agency, Office
of Wastewater Management, EPA-833-K-10-001. September 2010.
https://www3.epa.gov/npdes/pubs/pwm 2010.pdf
EPA, 2007. EPA Model Pretreatment Ordinance, Office of Wastewater
Management/Permits Division, January 2007.
EPA, 2011. Introduction to the National Pretreatment Program, Office of Wastewater
Management, EPA 833-B-11-011, June 2011.
EPA. 2014. Water Quality Standards Handbook Chapter 5: General Policies.
Environmental Protection Agency. Office of Water. EPA 820-B-14-004. September
2014. https://www.epa.gov/sites/production/files/2014-09/documents/handbook-
chapter5.pdf
Stuart, T. 2022. Hangman Creek Watershed Nutrients and Sediment Pollutant Source
Assessment, 2018. Publication 22-03-004. Washington State Department of Ecology,
Olympia.
https://apps.ecologv.wa.gov/publications/SummarvPages/2203004.html
Washington State, 2010, Spokane River and Lake Spokane Dissolved Oxygen TMDL.
Water Quality Program, Eastern Regional Office, Department of Ecology. Publication
no. 07-10-073. https://apps.ecologv.wa.gov/publications/documents/0710073.pdf
Washington State, 2011, Hangman (Latah) Creek Watershed Fecal Coliform Bacteria,
Temperature, and Turbidity Total Maximum Daily Load Water Quality Implementation
Plan. Water Quality Program, Eastern Regional Office, Department of Ecology
Publication no. 09-10-030.
https://apps.ecologv.wa.gov/publications/documents/0910030.pdf
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 32 of 52
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Appendix A. Facility Information
^charae6 c't> of Worley WWTF
Location
N
Aerated Cell
Figure 1. Map of facility
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
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Figure 2. Facility diagram
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 34 of 52
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Appendix B. Water Quality Data
Treatment Plant Effluent Data
Table 14. DMR data of BODs between November 2016 and May 2021
Effluent
Sewage Influent j
Parameter Desc
BOD, 7 day in mg/L
BOD, 7day in Ibs/dav
BOD, 30day in mg/L
*OD, 30day in lbs/da
BOD, % Removal
BOD, JOday in mg/L
DMR
Limit
DMR
Limit
DMR
Limit
DMR
Limit
DMR
Limit
Monitoring
Period End
Date
DMR
Monitorin
gEnd
Date
Effluent Gross 7.75 45. 13.84 21.4 7.75 30. 13.84 14.3 70.
85. 03/31/2017
25.5 03/31/2017
Effluent Gross 5.65 45. 14.05 21.4 5.65 30. 14.05 14.3 86. 85. 04/30/2017
Effluent Gross 5.65 45. 12.82 21.4 5.65 30. 12.82 14.3 87. 85. 03/31/2018
39. 04/30/2017
50. 03/31/2018
Effluent Gross 6.6 45. 13.65 21.4 6.6 30. 13.65 14.3 91. 85. 04/30/2018
67.5 04/30/2018
Effluent Gross 2.85 45. 3.93 21.4 2.85 30. 3.93 14.3 97. 85. 05/31/2018
89.5 05/31/2018
Effluent Gross 8.14 45. 21.12 21.4 8.14 30. 12.12 14.3 92. 85. 04/30/2019
84.5 04/30/2019
Effluent Gross 13.55 45.
39.33
21.4 13.55 30.
39.33
14.3 97. 85. 05/31/2020
440. 05/31/2020
I Effluent Gross 12. 45.
29.22
21.4 12. 30.
29.22
14.3 95. 85. 04/30/20211
230. 04/30/2021
Average 7.77
18.50
7.77
17.37
89.38
128.25
Minimum 2.85
3.93
2.85
3.93
70.00
25.50
Maximum 13.55
39.33
13.55
39.33
97.00
440.00
Count 8
8
8
8
3
8
StdDev 3.51
11.12
3.51
11.27
8.86
141.06
CV 0.45
0.60
0.45
0.65
0.10
1.10
95th Percentile 13.01
35.79
13.01
35.79
97.00
366.50
5th Percentile 3.83
7.04
3 33
6.80
75.60
30.23
90th percentile 12.47
32.25
12.47
32.25
97.00
293.00
Table 15. DMR data of BODs percent removal between November 2016 and May 2021
Limits. Monitoring
Location Desc
8
Parameter
Code
~
Parameter Desc
S
DMR Parameters
Monitoring
Location Desg
Statistical
Base Short
Desc
~
DMR
Value
S
Limit
Value
D
Limit Unit
Desc
S
Monitoring Period
Start Date
B
Monitoring
Period End Date
Ql
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
70.
85.
Percent
3/1/2017
03/31/2017
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
86.
85.
Percent
4/1/2017
04/30/2017
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
87.
85.
Percent
3/1/2018
03/31/2018
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
91.
85.
Percent
4/1/2018
04/30/2018
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
97.
85.
Percent
5/1/2018
05/31/2018
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
92.
85.
Percent
4/1)2019
04/30/2019
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
97.
85.
Percent
5/1/2020
05/31/2020
Percent Removal
81010
BOD, 5-day, percent removal
Percent Removal
MO AV MN
95.
85.
Percent
4/1/2021
04/30/2021
Maximum
97.00
Minimum
70.00
Average
89.38
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 35 of 52
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Table 16. DMR data of Total Residual Chlorine between November 2016 and May 2021
Parameter Desc
Daily Max
Concentration
Daily Max Loading
Monthly Average
Concentration
Monthly Average
Loading
Monitoring
Period End
mg/L
lbs/day
mg/L
lbs/day
Date
DMR
Limit
DMR
Limit
DMR
Limit
DMR
Limit
Chlorine, total residual
.36
.013
.65
.024
.05
.011
I .09
.024
03/31/2017
Chlorine, total residual
.52
.013
1.3
.024
.05
.011
.13
.024
04/30/2017
Chlorine, total residual
.12
.013
.28
.024
.02
.011
.01
.024
03/31/2018
Chlorine, total residual
.19
.013
.4
.024
.01
.011
.02
.024
04/30/2018
Chlorine, total residual
.25
.013
.35
.024
.02
.011
.03
.024
05/31/2018
Chlorine, total residual
.009
.013
.024
.024
.004
.011
.011
.024
04/30/2019
Chlorine, total residual
.007
.013
.02
.024
.001
.011
.01
.024
05/31/2020
Chlorine, total residual
.003
.013
.02
.024
.001
.011
.002
.024
04/30/2021
Average
0.183
0.381
0.020
0.038
Minimum
0.007
0.020
0.001
0.002
Maximum
0.520
1.300
0.050
0.130
Count
8
8
8
8
Std Dev
0.187
0.434
0.020
0.047
CV
1.023
1.140
1.039
1.228
95th Percentile
0.464
1.073
0.050
0.116
5th Percentile
0.007
0.020
0.001
0 005
90th percentile
0.403
0.845
0.050
0.102
Table 17. DMR data of E. co//bacteria between November 2016 and May 2021
Limits. Monitoring
Location Desc Q
Parameter
CocleQ
Parameter Desc
~
DMR Parameters
Monitoring __
Location DescH
Statistical
Base Shor^.
Desc Q
DMR
ValucQ
Limit
ValufQ
Limit Unit Desc _
~
Monitoring Period
Start Date Q
Monitoring
Period End Da Q
Effluent Gross
r
31643
E. coli, MTEC-MF
Effluent Gross
INST MAX
52.00
235.
Colony Forming Units per 100ml
3/1/2017
03/31/2017
Effluent Gross
t
31643
E. coli, MTEC-MF
Effluent Gross
INST MAX
8.50
235.
Colony Forming Units per 100ml
4/1/2017
04/30/2017
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
INST MAX
2.00
235.
Colony Forming Unrts per 100ml
3/1/2018
03/31/2018
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
INST MAX
10.90
235.
Colony Forming Units per 100ml
4/1/2018
04/30/2018
Effluent Gross
r
r
r
31648
E. coli, MTEC-MF
Effluent Gross
INST MAX
7.30
235.
Colony Forming Units per 100ml
5/1/2018
05/31/2018
Effluent Gross
31648
E. coli, MTEC-MF
Effluent Gross
INST MAX
230.00
235.
Colony Forming Units per 100ml
4/1/2019
04/30/2019
Effluent Gross
31648
E. coli, MTEC-MF
Effluent Gross
INST MAX
22.60
235.
Colony Forming Units per 100ml
5/1/2020
05/31/2020
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
INST MAX
27.52
235.
Colony Forming Units per 100ml
4/1/2021
04/30/2021
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.00
126.
Colony Forming Units per 100ml
3/1/2017
03/31/2017
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.00
126.
Colony Forming Units per 100ml
4/1/2017
04/30/2017
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.00
126.
Colony Forming Units per 100ml
3/1/2018
03/31/2018
Effluent Gross
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
2.76
126.
Colony Forming Units per 100ml
4/1/2018
04/30/2018
Effluent Gross
f
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.12
126.
Colony Forming Units per 100ml
5/1/2018
05/31/2018
Effluent Gross
[
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.00
126.
Colony Forming Units per 100ml
4/1/2019
04/30/2019
Effluent Gross
:
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.00
126.
Colony Forming Units per 100ml
5/1/2020
05/31/2020
Effluent Gross
r
31648
E. coli, MTEC-MF
Effluent Gross
MO GEOMN
0.00
126.
Colony Forming Units per 100ml
4/1/2021
04/30/2021
INST MAX min 2.00
max 230.00
MO GEOMN min 0.00
max 2.76
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 36 of 52
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Table 18. DMR data of the effluent dilution ratio between November 2016 and May 2021
Limits.
Monitoring
Location DesH
Parameter
Code Q
Parameter Desc _
DMR Parameters
Monitoring _
Location DescD
Statistical Base
Short DescJJj
DMR
Valuegj
Limit
ValutQ
Limit Unit
Desc
Monitoring
Period Start^
Date D
Monitoring
Period End DsQ
Effluent Gross
r 78480
Effluent dilution ratio
Effluent Gross
M O MIN
10.
10.
Ratio
3/1/2017
03/31/2017
Effluent Gross
r 78480
Effluent dilution ratio
Effluent Gross
MO MIN
10.
10.
Ratio
4/1/2017
04/30/2017
Effluent Gross
78480
Effluent dilution ratio
Effluent Gross
MO MIN
20.
10.
Ratio
3/1/2018
03/31/2018
Effluent Gross
T 78480
Effluent dilution ratio
Effluent Gross
MO MIN
H
10.
Ratio
4/1/2018
04/30/2018
Effluent Gross
[ 78480
Effluent dilution ratio
Effluent Gross
MO MIN
10.
10.
Ratio
5/1/2018
05/31/2018
Effluent Gross
[ 78480
Effluent dilution ratio
Effluent Gross
MO MIN
10.
10.
Ratio
4/1/2019
04/30/2019
Effluent Gross
f 78480
Effluent dilution ratio
Effluent Gross
MO MIN
10.
10.
Ratio
5/1/2020
05/31/2020
Effluent Gross
\ 78480
Effluent dilution ratio
Effluent Gross
MO MIN
10.
10.
Ratio
4/1/2021
04/30/2021
Table 19. DMR data of the facility discharge flow between November 2016 and May 2021
Limits.
Monitoring
Location DesQ
Parameter
Code g
Parameter Desc
DMR Parameters
Monitoring
Location Desfl
Statistical Base
Short Desc g
DMR
Valuegj
Limit
Valueg
Limit Unit Desc
Monitoring Period
Start Date g
Monitoring Period
End Date g
Effluent Gross
;
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MOAVG
.271
Million Gallons per Day
3/1/2017
03/31/2017
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MOAVG
.298
Million Gallons per Day
4/1/2017
04/30/2017
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MOAVG
.272
Million Gallons per Day
3/1/2018
03/31/2018
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MOAVG
.248
Million Gallons per Day
4/1/2018
04/30/2018
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO AVG
.165
Million Gallons per Day
5/1/2018
05/31/2018
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MOAVG
.365
Million Gallons per Day
4/1/2019
04/30/2019
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MOAVG
.348
Million Gallons per Day
5/1/2020
05/31/2020
Effluent Gross
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO AVG
.292
Million Gallons per Day
4/1/2021
04/30/2021
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.4
Million Gallons per Day
3/1/2017
03/31/2017
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.298
Million Gallons per Day
4/1/2017
04/30/2017
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.441
Million Gallons per Day
3/1/2018
03/31/2018
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.366
Million Gallons per Day
4/1/2018
04/30/2018
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.291
Million Gallons per Day
5/1/2018
05/31/2018
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.365
Million Gallons per Day
4/1/2019
04/30/2019
Effluent Gross
r
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.589
Million Gallons per Day
5/1/2020
05/31/2020
Effluent Gross
:
50050
Flow, in conduit or thru treatment plant
Effluent Gross
MO MAX
.567
Million Gallons per Day
4/1/2021
04/30/2021
Monthly Ave
Monthly Max
Min
0.165
0.291
Avq
0.282
0.415
Max
0.365
0.589
Table 20. DMR data of nitrite+nitrate between November 2016 and May 2021
Limits.
Monitoring
Location DesQ
Parameter
Code g
Parameter Desc
DMR Parameters
Monitoring
Location DescQ
Statistical Base
Short Descg
DMR
Valuegj
Limit
Valueg
Limit Unit Desc
Monitoring Period
Start Date g
Monitoring Period
End Date g
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO M.AX
10.20
Mi
lligrams per Liter
3/1/2017
03/31/2017
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO MAX
0.00
Mi
lligrams per Liter
4/1/2017
04/30/2017
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO MAX
0.24
Mi
lligrams per Liter
3/1/2018
03/31/2018
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO MAX
0.78
Mi
lligrams per Liter
4/1/2018
04/30/2018
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO MAX
0.59
Mi
lligrams per Liter
5/1/2018
05/31/2018
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO MAX
0.23
Mi
lligrams per Liter
4/1/2019
04/30/2019
Effluent Gross
00630
Nitrite + Nitrate total [as N]
Effluent Gross
MO MAX
0.37
Mi
lligrams per Liter
5/1/2020
05/31/2020
Effluent Gross
00630
Nitrite + Nitrate total [as NJ
Effluent Gross
MO MAX
0.16
Mi
lligrams per Liter
4/1/2021
04/30/2021
min
0.00
max
10.20
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 37 of 52
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Table 21. DMR data of total ammonia between November 2016 and May 2021
Parameter Desc
Daily Max
Concentration
Daily Max Loading
Monthly Average
Concentration
Monthly Average
Loading
Monitoring
Period End
Date
rng/L
lbs/day
mg/L
lbs/day
DMR
Limit
DMR I Limit
DMR
Limit
DMR
Limit
N
trogen, ammonia total [as N]
2.12
10.6
3.79
5.1
1.92
4.1
3.43
1.9
03/31/2017
N
trogen, ammonia total [as N]
.68
10.6
1.69
5.1
.03
4.1
.08
1.9
04/30/2017
trogen, ammonia total [as N]
6.05
10.6
13.73
5.1
.2
4.1
.46
1.9
03/31/2018
N
trogen, ammonia total [as N]
5.27
10.6
10.9
5.1
5.08
4.1
10.51
1.9
04/30/2018
N
trogen, ammonia total [as N]
5.42
10.6
7.46
5.1
5.23
4.1
7.2
1.9
05/31/2018
trogen, ammonia total [as N]
6.61
10.6
17.5
5.1
5.98
4.1
15.51
1.9
04/30/2019
N
trogen, ammonia total [as N]
9.96
10.6
28.91
5.1
9.28
4.1
26.94
1.9
05/31/2020
N
trogen, ammonia total [as N]
10.85
10.6
26.42
5.1
10.85
4.1
26.42
1.9
04i30/2021
Average
5.870
13.800
4.821
11.319
Minimum
0.680
1.690
0.030
0.080
Maximum
10.850
28.910
10.850
26.940
Count
8
8
8
8
Std Dev
3.457
9.977
3.974
10.782
cv
0.589
0.723
0.824
0.953
95th Percentile
10.539
28.039
10.301
26.758
5th Percentile
1.184
2.425
0.090
0.213
90th percentile
10.227
27.167
9.751
26.576
Table 22. DMR data of total Kjeldahl nitrogen between November 2016 and May 2021
Limits.
Monitoring
Location DesH
Parameter Parameter Desc
Code g ~
DMR Parameters .. , _
Monitoring Location Statical Base
Desc P( Short Desc B
DMRValu^
Limit
Valueg
Limit Unit Desc
a ~
Monitoring
Period Start
Date
Monitoring
Period End
Date D
Effluent Gross
^0625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
8.67
Milligrams per Liter
3/1/2017
03/31/2017
Effluent Gross
[00625
Nitrogen, Kjeldahl, total las N]
Effluent Gross
MO MAX
3.73
Milligrams per Liter
4/1/2017
04/30/2017
Effluent Gross
I00625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
8.34
Milligrams per Liter
3/1/2018
03/31/2018
Effluent Gross
I00625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
8.52
Milligrams per Liter
4/1/2018
04/30/2018
Effluent Gross
|00625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
6.57
Milligrams per Liter
5/1/2018
05/31/2018
Effluent Gross
[00625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
8.11
Milligrams per Liter
4/1/2019
04/30/2019
Effluent Gross
[00625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
14.4
Milligrams per Liter
5/1/2020
05/31/2020
Effluent Gross
[00625
Nitrogen, Kjeldahl, total [as N]
Effluent Gross
MO MAX
16.2
Milligrams per Liter
4/1/2021
04/30/2021
Effluent Gross
[00625
Nitrogen, Kjeldahl, total las N]
Effluent Gross
MO MAX
Milligrams per Liter
5/1/2021
05/31/2021
min
3.7
max
16.2
Table 23. DMR data of dissolved oxygen between November 2016 and May 2021
Limits. Monitoring
Location Desc
D
Parameter
Code
D
Parameter Desc
B
DMR Parameters
Monitoring
Location Desc
H
Statistical Base
Short Desc
B
DMR
Value
~
Limit
Value
D
Limit Unit Desc
a
Monitoring Period
Start Date
~
Monitoring Period
End Date
Q
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
4.5
Milligrams per Liter
3/1/2017
03/31/2017
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
7.1
Milligrams per Liter
4/1/2017
04/30/2017
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
5.7
Milligrams per Liter
3/1/2018
03/31/2018
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
5.7
Milligrams per Liter
4/1/2018
04/30/2018
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
115
Milligrams per Liter
5/1/2018
05/31/2018
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
11.7
Milligrams per Liter
4/1/2019
04/30/2019
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
11.5
Milligrams per Liter
5/1/2020
05/31/2020
Effluent Gross
00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
11.2
Milligrams per Liter
4/1/2021
04/30/2021
Effluent Gross
V 00300
Oxygen, dissolved [DO]
Effluent Gross
MO MIN
Milligrams per Liter
5/1/2021
05/31/2021
min
4.5
max
11-7
Table 24. DMR data of pH between November 2016 and May 2021
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 38 of 52
-------
Limits. Monitoring
Location Desc
~
Parameter Code
a
Parameter
Desc g
DMR Parameters
Monitoring
Location DescQ
Statistical Base
Short Desc g
DMR Va,u^
Limit Valu^
Limit Unit Des<^
Monitoring Period
Start Date g
Monitoring
Period End Deg
Effluent Gross
r
00400
PH
Effluent Gross
INST MAX
7.4
8.5
Standard Units
3/1/2017
03/31/2017
Effluent Gross
00400
PH
Effluent Gross
INST MAX
7.5
8.5
Standard Units
4/1/2017
04/30/2017
Effluent Gross
00400
PH
Effluent Gross
INST MAX
7.6
8.5
Standard Units
3/1/2018
03/31/2018
Effluent Gross
00400
PH
Effluent Gross
INST MAX
7.6
8.5
Standard Units
4/1/2018
04/30/2018
Effluent Gross
00400
PH
Effluent Gross
INST MAX
7.4
8.5
Standard Units
5/1/2018
05/31/2018
Effluent Gross
00400
PH
Effluent Gross
INST MAX
8.0
8.5
Standard Units
4/1/2019
04/30/2019
Effluent Gross
00400
PH
Effluent Gross
INST M.AX
8.0
8.5
Standard Units
5/1/2020
05/31/2020
Effluent Gross
00400
pH
Effluent Gross
INST MAX
7.9
8.5
Standard Units
4/1/2021
04/30/2021
Effluent Gross
00400
pH
Effluent Gross
INSTMIN
6.9
6.5
Standard Units
3/1/2017
03/31/2017
Effluent Gross
00400
PH
Effluent Gross
INSTMIN
7.2
6.5
Standard Units
4/1/2017
04/30/2017
Effluent Gross
00400
PH
Effluent Gross
INST MIN
7.1
6.5
Standard Units
3/1/2018
03/31/2018
Effluent Gross
00400
PH
Effluent Gross
INSTMIN
7.2
6.5
Standard Units
4/1/2018
04/30/2018
Effluent Gross
00400
PH
Effluent Gross
INSTMIN
7.2
6.5
Standard Units
5/1/2018
05/31/2018
Effluent Gross
00400
PH
Effluent Gross
INSTMIN
7.3
6.5
Standard Units
4/1/2019
04/30/2019
Effluent Gross
00400
PH
Effluent Gross
INST MIN
7.3
6.5
Standard Units
5/1/2020
05/31/2020
Effluent Gross
00400
PH
Effluent Gross
INSTMIN
7.8
6.5
Standard Units
4/1/2021
04/30/2021
Effluent Gross
00400
PH
Effluent Gross
INSTMIN
6.5
Standard Units
5/1/2021
05/31/2021
min
6.9
max
8.0
Table 25. DMR data of total phosphorus between November 2016 and May 2021
Limits. Monitoring
Location Desc g
Parameter
Code g
Parameter Desc
DMR Parameters
Monitoring Location Desg
Statistical Base
Short Desc g
DMR
Valuegj
Limit
Valueg
Limit Unit Desc
Monitoring Period
Start Date g
Monitoring
Period End Cum
Effluent Gross
r
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
1.63
Milligrams per Liter
3/1/2017
03/31/2017
Effluent Gross
W
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
1.08
Milligrams per Liter
4/1/2017
04/30/2017
Effluent Gross
f
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
1.91
Milligrams per Liter
3/1/2018
03/31/2018
Effluent Gross
f
L
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
1.75
Milligrams per Liter
4/1/2018
04/30/2018
Effluent Gross
r
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
1.7
Milligrams per Liter
5/1/2018
05/31/2018
Effluent Gross
r
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
2.52
Milligrams per Liter
4/1/2019
04/30/2019
Effluent Gross
r
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
3.74
Milligrams per Liter
5/1/2020
05/31/2020
Effluent Gross
f
00665
Phosphorus, total [as P]
Effluent Gross
MO MAX
3,98
Milligrams per Liter
4/1/2021
04/30/2021
min
1.08
max
3.98
Table 26. DMR data of total suspended solids between November 2016 and May 2021
I Effluent
Sewage Influent |
Parameter
Desc
TSS, 7 day
in mg/L
TSS, 7day
in lbs/day
TSSf 30day in mg/L
TSS, %
emoval
Monitoring
TSS, 30day in mg/L
DMR
Limit
DMR
Limit
DMR
Limit
DMR
Limit
DMR
Limit
Period End
Date
DMR
Monitoring End
Date
Effluent Gross
27.
45.
48.19
21.4
27
30
48.19
14.3
77.
85 03/31/20171
115.
03/31/2017
Effluent Gross
16.
45.
39.77
21.4
16
30
39.77
14.3
73.
85
04/30/2017
58.35
04/30/2017
Effluent Gross
16.5
45.
37.43
21.4
16.5
30
37.43
14.3
80.
85
03/31/2018
143,
03/31/2018
Effluent Gross
19.5
45.
40.34
21.4
19.5
30
40.34
14.3
88.
85
04/30/2018
159.5
04/30/2018
Effluent Gross
8.
45.
11.01
21.4
8
30
11 01
14.3
96.
85 05/31/2018
166.
05/31/2018
Effluent Gross
28.84
45.
74.81
21.4
28.84
30
74.81
14.3
72.
85
04/30/2019
136.5
04/30/2019
Effluent Gross
22.
45.
63.86
21.4
22
30
63.86
14.3
92.
85
05/31/2020
258.5
05/31/2020
Effluent Gross
23.
45.
56.01
21.4
23
30
56.01
14.3
85.
85
04/30/2021
298.
04/30/2021
Minimum
8.0
11.0
8.0
11.0
72.0
58.4
Maximum
28.8
74.8
28.8
74.8
96.0
298.0
95th Percentih
28.2
71.0
28.2
71.0
94.6
284.2
Averaqe
20.11
46.43
20.11
46.43
82.88
166.86
Fact Sheet: ID0022713 - City of Worley Wastewater Treatment Plant
Page 39 of 52
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Table 27. DMR data of total suspended solids percent removal between November 2016 and
May 2021
Limits. Monitoring
Location Desc g
Parameter
Code g
Parameter Desc
DMR Parameters
Monitoring Location Beg
Statistical Base
Short Desc g
DMR
Valuegj
Limit
Vaiu eg
Limit Unit Des
-------
Receiving Water Data
Receiving water data from the Surface Water Monitoring Report between November
May 2021
City of Worley
Surface Water Monitoring
Date
Flow
pH
Temp. F
Temp. C
Total
Ammonia
Total
Phosphorus
Nitrate +
Nitrite
TKN
Dissolved
Oxygen
2/17/2016
5,000
6.9
42.6
5.89
ND
0.096
1.36
0.525
12.6
4/19/2016
3,000
6.8
51
10.56
0.122
0.132
ND
0.611
10.8
5/11/2016
1,500
7.2
51.2
10.67
0.096
0.104
ND
0.792
9.7
3/22/2017
5,200
6.8
39.3
4.06
ND
0.126
ND
0.613
12.2
4/5/2017
3,000
6.9
44
6.67
ND
0.105
ND
0.99
10.6
3/20/2018
3,200
7
43.5
6.39
0.075
0.12
0.918
0.475
11.8
4/4/2018
3,000
6.8
46.6
8.11
0.155
0.091
0.378
0.584
10.8
5/2/2018
2,500
6.9
52.5
11.39
0.13
0.143
0.21
0.635
10.2
4/10/2019
3,200
7.3
53.5
11.94
0.115
0.16
1.15
0.649
11.7
4/21/2020
3,500
6.9
51
10.56
ND
0.067
ND
0.448
10.6
Average
3310
7.0
47.5
8.62 0.116
0.114
0.803
0.632
11.1
Minimum
1500
6.8
39.3
4.06 0.075
0.067
0.210
0.448
9.7
Maximum
5200
7.3
53.5
11.94 0.155
0.160
1.360
0.990
12.6
Count
10
10.0
10.0
10.00 6.000
10.000
5,000
10.000
10.0
Std Dev
1091
0.2
4.9
2.74 0.028
0.027
0.494
0.159
0.9
CV
0
0.0
0.1
0.32 0.240
0.239
0.615
0.251
0.1
95th Percentile
5110
7.3
53.1
11.69 0.149
0.152
1.318
0.901
12.4
5th Percentile
1950
6.8
40.8
4.88 0.080
0.078
0.244
0.460
9.9
90th percentile
5020
7.2
52.6
11.44 0.143
0.145
1.276
0,812
12.2
Notes
ND: non-detect
Ammonia dection limit: 0.05
Nitrate-nitrite detection limit: 0.1
Table 29.
2016 and
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Appendix C. Reasonable Potential and WQBEL Formulae
A. Reasonable Potential Analysis
EPA uses the process described in the Technical Support Document for Water
Quality-based Toxics Control (EPA, 1991) to determine reasonable potential. To
determine if there is reasonable potential for the discharge to cause or contribute to an
exceedance of water quality criteria for a given pollutant, EPA compares the maximum
projected receiving water concentration to the water quality criteria for that pollutant. If
the projected receiving water concentration exceeds the criteria, there is reasonable
potential, and a WQBEL must be included in the permit.
1. Mass Balance
For discharges to flowing water bodies, the maximum projected receiving water
concentration is determined using the following mass balance equation:
CdQd = CeQe + CuQu Equation 1
where,
Receiving water concentration downstream of the effluent
discharge (that is, the concentration at the edge of the
mixing zone)
Maximum projected effluent concentration
95th percentile measured receiving water upstream
concentration
Receiving water flow rate downstream of the effluent
discharge = Qe+Qu
Effluent flow rate (set equal to the design flow of the
WWTP)
Receiving water low flow rate upstream of the discharge
(1Q10, 7Q10 or 30B3)
Cd
Ce
Cu
Qd =
Qe =
Qu =
When the mass balance equation is solved for Cd, it becomes:
= Ce x Qe + Cu x Qu Equation 2
Qe + Qu
The above form of the equation is based on the assumption that the discharge is
rapidly and completely mixed with 100% of the receiving stream.
If the mixing zone is based on less than complete mixing with the receiving water,
the equation becomes:
Ce X Qe + Cu X (Qu X %MZ)
Cd = t r Equation 3
Qe + (Qu x %MZ) 4
Where:
% MZ = the percentage of the receiving water flow available for mixing.
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If a mixing zone is not allowed, dilution is not considered when projecting the
receiving water concentration and,
Cd = Ce Equation 4
A dilution factor (D) can be introduced to describe the allowable mixing. Where
the dilution factor is expressed as:
n _ Qe + Qu x %MZ
u ~ Equation 5
After the dilution factor simplification, the mass balance equation becomes:
^ _Ce-Cu ^
Cd p+CU Equation 6
If the criterion is expressed as dissolved metal, the effluent concentrations are
measured in total recoverable metal and must be converted to dissolved metal as
follows:
^ CFxCe-Cu ^
Cd= ^-+CU Equation 7
D
Where Ce is expressed as total recoverable metal, Cu and Cd are expressed as
dissolved metal, and CF is a conversion factor used to convert between dissolved
and total recoverable metal.
The above equations for Cd are the forms of the mass balance equation which
were used to determine reasonable potential and calculate wasteload allocations.
2. Maximum Projected Effluent Concentration
When determining the projected receiving water concentration downstream of the
effluent discharge, EPA's Technical Support Document for Water Quality-based
Toxics Controls (TSD, 1991) recommends using the maximum projected effluent
concentration (Ce) in the mass balance calculation (see equation 3, page C-5). To
determine the maximum projected effluent concentration (Ce) EPA has developed
a statistical approach to better characterize the effects of effluent variability. The
approach combines knowledge of effluent variability as estimated by a coefficient
of variation (CV) with the uncertainty due to a limited number of data to project an
estimated maximum concentration for the effluent. Once the CV for each pollutant
parameter has been calculated, the reasonable potential multiplier (RPM) used to
derive the maximum projected effluent concentration (Ce) can be calculated using
the following equations:
First, the percentile represented by the highest reported concentration is
calculated.
pn = (1 - confidence level)1/n Equation 8
where,
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n
the percentile represented by the highest reported concentration
the number of samples
confidence level = 99% = 0.99
and
CPn eZPnxa-0.5xa:
Where,
Equation 9
a2 = ln(CV2 +1)
Z99 = 2.326 (z-score for the 99th percentile)
^ _ z-score for the Pn percentile (inverse of the normal
Pn cumulative distribution function at a given percentile)
CV = coefficient of variation (standard deviation mean)
The maximum projected effluent concentration is determined by simply multiplying
the maximum reported effluent concentration by the RPM:
where MRC = Maximum Reported Concentration
3. Maximum Projected Effluent Concentration at the Edge of the Mixing Zone
Once the maximum projected effluent concentration is calculated, the maximum
projected effluent concentration at the edge of the acute and chronic mixing
zones is calculated using the mass balance equations presented previously.
4. Reasonable Potential
The discharge has reasonable potential to cause or contribute to an exceedance
of water quality criteria if the maximum projected concentration of the pollutant at
the edge of the mixing zone exceeds the most stringent criterion for that pollutant.
B. WQBEL Calculations
1. Calculate the Wasteload Allocations (WLAs)
Wasteload allocations (WLAs) are calculated using the same mass balance
equations used to calculate the concentration of the pollutant at the edge of the
mixing zone in the reasonable potential analysis. To calculate the wasteload
allocations, Cd is set equal to the acute or chronic criterion and the equation is
solved for Ce. The calculated Ce is the acute or chronic WLA. Equation 6 is
rearranged to solve for the WLA, becoming:
Ce = WLA = D x (Cd - Cu) + Cu Equation 11
Washington's water quality criteria for some metals are expressed as the
dissolved fraction, but the Federal regulation at 40 CFR 122.45(c) requires that
effluent limits be expressed as total recoverable metal. Therefore, EPA must
Ce = (RPM)(MRC)
Equation 10
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calculate a wasteload allocation in total recoverable metal that will be protective of
the dissolved criterion. This is accomplished by dividing the WLA expressed as
dissolved by the criteria translator, as shown in equation . As discussed in
Appendix , the criteria translator (CT) is equal to the conversion factor,
because site-specific translators are not available for this discharge.
Dx(Cd-Cu)+Cu
Ce=WLA=- Equation 12
OT
The next step is to compute the "long term average" concentrations which will be
protective of the WLAs. This is done using the following equations from EPA's
Technical Support Document for Water Quality-based Toxics Control (TSD):
LTAa=WLAaxe(°-5c72~zc7) Equation 13
LTAc=WLAcxe(05c74 -z^) Equation 14
where,
a2 = ln(CV2 +1)
Z99 = 2.326 (z-score for the 99th percentile probability basis)
CV = coefficient of variation (standard deviation mean)
o4 2 = ln(CV2/4 + 1)
For ammonia, because the chronic criterion is based on a 30-day averaging
period, the Chronic Long Term Average (LTAc) is calculated as follows:
LTAc=WLAcxe(° ¦5<7fo ~ Z(730 ) Equation 15
where,
0302 = ln(CV2/30 + 1)
The LTAs are compared and the more stringent is used to develop the daily
maximum and monthly average permit limits as shown below.
2. Derive the maximum daily and average monthly effluent limits
Using the TSD equations, the MDL and AML effluent limits are calculated as
follows:
MDL = LTA x e^°-°-5ct2) Equation 16
AML = LTA x e(ZaCTn"a5cT" Equation 11
where o, and o2 are defined as they are for the LTA equations above, and,
on2 = ln(CV2/n +1
za = 1.645 (z-score for the 95th percentile probability basis)
zm = 2.326 (z-score for the 99th percentile probability basis)
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number of sampling events required per month. With
the exception of ammonia, if the AML is based on the
LTAc, i.e., LTAminimum = LTAc), the value of "n" should is
n = set at a minimum of 4. For ammonia, In the case of
ammonia, if the AML is based on the LTAc, i.e.,
LTAminimum = LTAc), the value of "n" should is set at a
minimum of 30.
C. Critical Low Flow Conditions
The low flow conditions of a water body are used to determine WQBELs. For North
Fork Rock Creek, no data on stream flow were available and the stream is dry for at
least a portion of the year as confirmed through aerial photography.
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Appendix D. Reasonable Potential and WQBEL Calculations
AMMONIA,^
CHLORINE
Pollutants of Concern
default: cold
water, fish
early life
stages
(Total
Residual)
Number of Samples in Data Set (n)
8
8
Effluent Data
Coefficient of Variation (CV) = Std. Dev./Mean (default CV = 0.6)
0.6
0.6
Effluent Concentration, |ig/L (Max. or 35th Percentile) -(C,)
10,850
520
Calculated 50" V. Effluent Cone, (when n>10) Human Health Only
Receiving Water Data
90" Percentile Cone., |ig/L - (C.)
Geometric Mean, |ig(L, Human Health Criteria'Onlji
Aquatic Life Criteria, i_-.g/L
^ Acute
18,330.88
13.
Aquatic Life Criteria, y.g/L
Chronic
5,206.137
11.
Applicable
Water Quality Criteria
Human Health Water and Organism, |j.g/L
Human Health, Organism Only, j.ig/L
Metals Criteria Translator, decimal (or default use
^ Acute
Carcinogen fr7N), Human Health Criteria Only
Lhronic
N
Aquatic Life - Acute
1Q10
oy.
oy.
Percent River Flow
Aquatic Life - Chronic
7Q10 or 4B3
oy.
Default Value =
0%
Human nealth - Non-Larcinogen and Uhronic
A
Human Health - Carcinogen
30B3 or 30Q10
30Q5
Harmonic Mean
oy.
oy.
oy.
oy.
Aquatic Life - Acute
1Q10
1.0
1.0
r
Calculated
Aquatic Life - Chronic
7010 or 4B3
1.0
r
Dilution Factors (DF)
(or enter Modeled DFs)
numan nealth - Non-Uarcinogen and Uhronic
A
30B3 or 30Q10
30Q5
Harmonic Mean
K 1.0
1.0
1.0
1.0
F
r
r
Aquatic Life Reasonable
Potential Analysis
C
oJ=ln(CV*+1)
0.555
0.555
p.
= (1-confidence level)1'" , w here confidence level =
33V.
0.562
0.562
Multiplier [TSD p. 57)
= enp(zi3-0.5c£)/eHp[norm£inv(Prte-0.5:32], where
33 X
3.3
3.3
Statistically projected critical discharge concentration (C )
36131
1731.62
Predicted man. conc.(ugZL) at Edg
e-of-Mining Zone
Acute
36131
1731.62
(note: for metals, concentration as dissolved using conversion factor as translator)
Chronic
36131
1731.62
Reasonable Potential to exceed Aquatic Life Criteria
YES
YES
Aquatic Life Effluent Limit Calculations
Number of Compliance Samples Enpected per month (n)
n used to calculate AML (if chronic
is limiting then use min= 4 or for ammonia min= 30)
30
4
LTA Coeff. Var. (CV), decimal
(Use CV of data set or default = 0.6)
0.600
0.600
Permit Limit Coeff. Var. (CV). decimal (Use CV from data set or default = 0.61
0.600
0.600
Acute WLA, ug/L
Cj = (Acute Criteria h MZJ - Cn (MZ,-1)
Acute
18,331
13.0
Chronic WLA, ug/L
Cj= (Chronic Criteria k MZJ - Culi(MZ(.-1)
Chronic
5,206
11.0
Long Term Ave (LTA).. ug/L
WLAc k enp(0.5c2-ze), Acute
33V.
5,904
6.1
OS"1 V: occurrence prob.)
WLAa k eKp(0.532-zc); ammonia n=30. Chronic
^33X
4,062
5.8
Limiting LTA, ug/L
used as basis for limits calculation
4,062
5.8
Applicable Metals Criteria Translator 1 metals limits as total recoverable)
Average Monthly Limit (AML), ug/L?
, where ^ occurrence prob =
35X
4,833
3
Maximum Daily Limit (MDL), uq/L , where X occurrence prob =
33Y.
12,654
18
Average Monthly Limit (AML), mg/L
4.8
0.003
Maximum Daily Limit (MDL). ma/L
12.7
0.018
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Appendix E. Essential Fish Habitat Assessment
Pursuant to the requirements for Essential Fish Habitat (EFH) assessments, this appendix contains
the following information:
Listing of EFH Species in the Facility Area
Description of the Facility and Discharge Location
EPA's Evaluation of Potential Effects to EFH
A. Listing of EFH Species in the Facility Area
All waterbodies used by anadromous salmon throughout Alaska must be considered for
EFH identification. According to NOAA Fisheries, the receiving water is a migrational
corridor for sockeye, coho, chum, and pink salmon.
B. Description of the Facility and Discharge Location
The activities and sources of wastewater at the Juneau-Mendenhall waste water
treatment facility are described in detail in Part II and Appendix A of this fact sheet. The
location of the outfall is described in Part III ("Receiving Water").
C. EPA's Evaluation of Potential Effects to EFH
Water quality is an important component of aquatic life habitat. NPDES permits are
developed to protect water quality in accordance with WQS. The standards protect the
beneficial uses of the waterbody, including all life stages of aquatic life. The development
of permit limits for an NPDES discharger includes the basic elements of ecological risk
analysis.
Protection of Aquatic Life in NPDES Permitting
EPA's approach to aquatic life protection is outlined in detail in the Technical Support
Document for Water Quality-based Toxics Control (EPA/505/2-90-001, March 1991). EPA
and states evaluate toxicological information from a wide range of species and life stages
in establishing water quality criteria for the protection of aquatic life.
The NPDES program evaluates a wide range of chemical constituents (as well as whole
effluent toxicity testing results) to identify pollutants of concern with respect to the criteria
values. When a facility discharges a pollutant at a level that has a "reasonable potential"
to exceed, or to contribute to an exceedance of, the water quality criteria, permit limits are
established to prevent exceedances of the criteria in the receiving water (outside any
authorized mixing zone).
Effects Determination
Since the proposed permit has been developed to protect aquatic life species in the
receiving water in accordance with the Washington WQS, EPA has determined that
issuance of this permit is not likely to adversely affect any EFH in the vicinity of the
discharge. EPA will provide NMFS with copies of the draft permit and fact sheet during the
public notice period. Any recommendations received from NMFS regarding EFH will be
considered prior to reissuance of this permit.
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Appendix F. CWA § 401 Certification
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 10
1200 Sixth Avenue, Suite 155
Seattle, WA 98101-3188
EPA hereby certifies that the conditions in the National Pollutant Discharge Elimination System
(NPDES) permit for the City of Worley Wastewater Treatment Plant, are necessary to assure
compliance with the applicable provisions of Sections 301, 302, 303, 306, and 307 of the CWA.
See CWA Section 401(a)(1), 33 U.S.C. 1341(a)(1); 40 CFR 124.53(e).
The State in which the discharge originates is responsible for issuing the CWA Section 401
certification pursuant to CWA Section 401(a)(1). When a NPDES permit is issued on Tribal Land,
the Tribe is the certifying authority where the Tribe has been approved by EPA for Treatment as a
State (TAS) pursuant to CWA Section 518(e) and 40 CFR § 131.8. Where a Tribe does not have
TAS, EPA is the certifying authority. The Coeur d'Alene Tribe does not have TAS for the portion
of the reservation where the discharge occurs. Therefore, EPA is responsible for issuing the CWA
Section 401 Certification for this permit.
Mathew J. Martinson P. E.
CAPT, USPHS
Branch Chief, Permits, Drinking Water, and
Infrastructure
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Appendix G. Antidegradation Analysis
The purpose of Washington's Antidegradation Policy is to:
1. Restore and maintain the highest possible quality of the surface waters of
Washington.
2. Describe situations under which water quality may be lowered from its current
condition.
3. Apply to human activities that are likely to have an impact on the water quality of
surface water.
4. Ensure that all human activities likely to contribute to a lowering of water quality,
at a minimum, apply all known, available, and reasonable methods of prevention,
control, and treatment.
5. Apply three tiers of protection (described below) for surface waters of the state.
i. Tier I is used to ensure existing and designated uses are maintained and
protected and applies to all waters and all sources of pollution.
ii. Tier II is used to ensure that waters of a higher quality than the criteria
assigned in this chapter are not degraded unless such lowering of water
quality is necessary and in the overriding public interest. Tier II applies
only to a specific list of polluting activities.
iii. Tier III is used to prevent the degradation of waters formally listed in this
chapter as "outstanding resource waters," and applies to all sources of
pollution.
EPA utilized Washington's WQS downstream from the discharge in North Fork Rock Creek to
establish discharge limits in the permit and accordingly, the antidegradation analysis was
completed for North Fork Rock Creek downstream of the discharge. The discharge proposed
in this permit should not cause a loss of beneficial uses because there have not been any
changes in the process of the existing facility, and there is no change in the design flow.
Therefore, EPA concludes that the discharge does not trigger the need for any further
antidegradation analysis beyond Tier I Protection.
Tier I Protection - Protection and maintenance of existing and designated uses
According to Washington's antidegradation policy, WAC 172-210A-310, this facility must meet
Tier I requirements. Existing and designated uses must be maintained and protected. No
degradation may be allowed that would interfere with, or become injurious to, existing or
designated uses, except as provided for in WAC 173-201A612. The waters of North Fork Rock
Creek in Washington downstream of the point of discharge are protected for the following
designated beneficial uses:
Industrial Water Supply;
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Wildlife Habitat;
Aesthetic Values.
The effluent limits in the permit ensure compliance with applicable numeric and narrative water
quality criteria. The numeric and narrative water quality criteria are set at levels that ensure
protection of the designated uses. As there is no information indicating the presence of existing
beneficial uses other than those that are designated, the draft permit ensures a level of water
quality necessary to protect the designated uses and, in compliance with WAC 173-201A-310
and 40 CFR 131.12(a)(1), also ensures that the level of water quality necessary to protect
existing uses is maintained and protected. If EPA receives information during the public
comment period demonstrating that there are existing uses for which North Fork Rock Creek is
not designated, EPA will consider this information before issuing a final permit and will
establish additional or more stringent permit conditions if necessary to ensure protection of
existing uses.
Tier II Protection - Protection of waters of higher quality than the standards
EPA determined that analysis for a Tier II Protection is not necessary because the facility is not
a new or expanded action that has the potential to cause measurable degradation to existing
water quality. According to WAC 173-210A-320(2), a facility must prepare a Tier II analysis
when the facility is planning a new or expanded action that has the potential to cause
measurable degradation to the physical, chemical, or biological quality of the water body.
Tier III Protection - Protection of Outstanding Resource Waters
EPA determined that a Tier III antidegradation analysis is not necessary because the receiving
water does not meet the conditions as an Outstanding Resource Water pertaining to WAC
173-201 A-330(1).
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Appendix H. Facility Map
Worley Wastewater Treatment Plant
6/6/2022
> I Coeurd'Alene Tribal Boundary
Washington-Idaho State Boundary
NHD Coastline
NHD Rivers pipeline R3 Swamp, Marsh
Stream / Perennial Connector Ice Mass
Intermittent / Epnemeral NHD Waterbody NHD Area
Carta?, Ditch I' Lake. Pond, Reser/oir ' Large Rivers
0.5
1 106.049
1 2 mi
-r1| H1 . ' i
0 12 4 km
12D22 Nfco*:*: Csrco^icn Earns3f Gscgrao^cs sio C 2022 "for Ton
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