National Pollutant Discharge Elimination System

PERMIT EVALUATION REPORT AND FACT SHEET

July 2011

Oregon Department of Environmental Quality

Northwest Region

2020 SW 4th Avenue, Suite 400

Portland, OR 97201

(503) 229-5263

DEQ logo-medium size.tifflocation.jpgplantsite.jpg

Permittee:

Pacific City Joint Water-Sanitary Authority

PO Box 520

Pacific City, OR 97135

Existing Permit Information:

File Number: 66100

Permit Number: 101519

Expiration Date: September 30, 2011

EPA Reference Number: OR-003006-6

Source Contact:

Tony Owen 503-665-6636

PCJWSA Manager

Source Location:

34005 Cape Kiwanda Drive

Pacific City, OR

Tillamook County

LLID:

1239555451826-1.5 D

Receiving Stream/Basin:

Nestucca River/Wilson-Trask-Nestucca Sub-basin /North Coast Basin

Proposed Action:

Renew Permit

Application Number: 967581

Date Received: 3/3/2011

Source Category:

NPDES Minor – Domestic

Sources Covered:

Domestic wastewater

Permit Writer:

Name: Lyle Christensen

Permit-Compliance Specialist/ Northwest Region

July 11, 2011

Table of Contents

1.0 INTRODUCTION

The Department of Environmental Quality (DEQ) proposes to renew the National Pollutant Discharge Elimination System (NPDES) permit for the Pacific City Joint Water and Sanitary Authority (PCJWSA) wastewater treatment facility located at 34005 Cape Kiwanda Drive in southern Tillamook County. This permit allows and regulates the discharge of treated domestic wastewater to Nestucca River in the Wilson-Trask-Nestucca Subbasin of the North Coast Basin.

The current NPDES Permit expires on September 30, 2011. DEQ received renewal application number 967581 from PCJWSA on March 3, 2011. Because the permittee submitted a renewal application to DEQ in a timely manner, the current permit will not expire until DEQ takes final action on the renewal application as per OAR 340-045-0040.

This permit evaluation report describes the basis and methodology used in developing the permit. The permit is divided into several sections:

Schedule A – Waste discharge limits

Schedule B – Minimum monitoring and reporting requirements

Schedule C – Compliance conditions and schedules

Schedule D – Special conditions

Schedule F – General conditions

The proposed permit contains the following substantive changes from the 2006 permit:

Schedule A – the pH lower limit has been modified slightly from 6.0 to 6.1 s.u.

Schedule B – “UV Dosage” is now required to be reported. Dosage is determined based on exposure time at a measured intensity. Monitoring for effluent alkalinity has been added to the permit.

Schedule D – A condition to evaluate the outfall diffuser is now included in the permit.

Schedule F – Has been updated since the last permit.

The Federal Water Pollution Control Act of 1972 and its subsequent amendments, as well as Oregon Revised Statutes (ORS 468B.050), require a NPDES permit for the discharge of wastewater to surface waters. This proposed permit action by DEQ complies with both federal and state requirements.

2.0 FACILITY DESCRIPTION

2.1 Wastewater Facilities Description

Wastewater enters the treatment facility influent pump station from both gravity and pressure sewer lines. The pumped influent passes over a side hill screen to capture trash and larger grit before entering a 100,000 gallon flow equalization basin (FEB). From the FEB the water is pumped to two 45,000 aeration basins which provide the activated sludge treatment of the wastewater. Two 25 foot diameter clarifiers that are 8 feet deep are used to separate the majority of the solids from the water prior to it entering a 30,000 gallon plant holding tank. From the holding tank the water is pumped to disk filtration (added in 2005) which is followed by UV disinfection (converted from chlorine in 2001) and then discharge to the Nestucca River. Solids separated out of the treatment process are placed in a 50,000 gallon aerobic digester. Though this facility is considered a continuous discharger, because influent enters an influent pump station and because it must also be pumped from the FEB and the holding tank, at times the facility may have zero flow leaving the plant.

The PCJWSA has about 1365 connections to a treatment facility that was designed to treat 360,000 gallons per day of flow during dry weather. In the past two years the reported average monthly flow during typically drier May through October period has been about 137,000 gallons per day, while in the wetter November through April period the reported average monthly flow

was about 114,000 gallons per day. The highest daily flow reported in the past two years was 350,000 gallons on May 21, 2011. Lower flows in the wetter months are likely due to the high number of homes in the community that are seasonally used second homes. In the first graph below a monthly average population equivalent (PE)* loading is noted to the facility. In the last five years the reported PE loading has increased slightly to the facility. Reviewing the next graph below, note that the average monthly flow has slightly decreased over the same time period.

* PE = flow (in mgd) times BOD influent concentration (in mg/L or parts per million) times a conversion factor (8.34 lbs/gallon) divided by an estimated pounds BOD per person per day (0.18).

2.2 Outfalls

Treated wastewater is discharged through Outfall 001 to the Nestucca River at river mile 1.5. The outfall diffuser was designed with four 3-inch diameter ports each separated by 9-feet along the outfall pipe with another single 3- inch port in the blind flange on the end of the twelve inch diameter outfall pipe that is about 4 ½ feet from the nearest other port. The 36–foot total length diffuser pipe is located about 180 feet off the west shore of the Nestucca River at a point where the river is about 350 feet wide. The diffuser is about 8-feet under low water level in the river.

2.3 Inflow and Infiltration

The permittee estimated that the contribution of flow due to inflow and infiltration (I&I) was about 10000 gallons per day. This permittee has not reported rainfall data, so it is difficult to correlate if rain events greatly influence plant flows. The discharge monitoring reports do show a definite pattern of higher flows on weekends and holidays reflecting the vacation home nature of much of this community.

Collection system overflows can result from catastrophic failure of the treatment plant or pump station or high flows due to storm events. The permit prohibits raw sewage discharge. The permittee has experienced no overflows during the prior permit cycle and can comply with this requirement.

Reviewing reported influent concentrations of total suspended solids (TSS), there are very few days where they are less than 200 mg/l. If concentrations were observed to be lower on a regular basis this could indicate I&I impacts. The permit requires a monthly average removal efficiency of 85 percent for both biochemical oxygen demand (BOD5) and TSS. The permittee has not violated these removal efficiency limits.

The permittee is required to continue to have a program in place to identify and reduce I&I into the sewage collection system and submit an annual report by February 1st each year which details sewer collection maintenance activities that aid in controlling I&I. The most recent I&I report found in the file was submitted in 2011.

2.4 Biosolids Management

Wastewater related solids are aerobically digested in a 50,000 gallon digester and then lime stabilized prior to beneficial land application on a PCJWSA owned 50 acre hay field site near the community of Beaver. An update of their 1994 approved biosolids management plan was included with the renewal application and is available for review during this permitting action.

2.5 Storm Water

Storm water is not addressed in this permit. General NPDES permits for stormwater are not required for facilities with a design flow of less than 1 MGD.

2.6 Groundwater

The wastewater is contained in water tight tanks at the treatment plant site which limit potential for groundwater impacts at this site. Biosolids applications are controlled at agronomic rates and the potential for groundwater impacts is considered minimal.

2.7 Industrial Pretreatment

The permittee does not have a DEQ-approved industrial pretreatment program. One is not required for this source based on current information.

3.0 PERMIT HISTORY

3.1 Permit History

The original NPDES permit was issued in 1976 prior to the construction of the wastewater facility serving Pacific City. The facility began operation in 1979 and that permit has been renewed in 1981, 1986, 1992, 1998, 2004 and 2006.

3.2 Compliance History

A review of the correspondence file for this facility found that PJWSA has had several enforcement actions since the last renewal. Warning letters were issued on February 5, 2007, August 21, 2008, October 30, 2008, January 26, 2010 and July 7, 2011. In 2008, PJWSA indicated that the violations were associated with some ongoing problems with laboratory testing equipment. In response to the problem, increased quality laboratory testing assurance efforts were initiated and follow-up testing was done using an outside testing lab’s quality assurance proficiency testing. The testing results indicated that the PCJWSA BOD5 results were coming back at higher levels than the known value. Permit violations noted in December 2009 were documented and attributed to plant performance being limited due to cold weather and inability to waste solids in a timely fashion. The violations cited in 2011 were again for violation of technology base limits for TSS and BOD5 noted in September 2010 and May 2011. Again these violations were observed over short periods of time and are not considered to be ongoing. DEQ’s most recent site visit and inspection occurred in May of 2010. The facility was found to be compliant with permit conditions and limitations at that time.

4.0 RECEIVING WATER

PCJWSA wastewater treatment facility discharges to the Nestucca River. The designated beneficial uses of the Nestucca River at this location are as follows:

 public and private domestic water supply,
 industrial water supply,
 irrigation and livestock watering,
 fish and aquatic life (including salmonid rearing, migration and spawning),
 wildlife and hunting,
 fishing,
 boating,
 water contact recreation,
 aesthetic quality,

and

 commercial navigation and transportation

The water quality standards for the North Coast Basin were developed to protect these beneficial uses and can be found in Oregon Administrative Rules 340-041-0235.

4.1 Receiving Stream Water Quality

The Nestucca River flows about fifty miles from the Coast Range to the Pacific Ocean through a bay that starts a little more than 1 mile downstream from the wastewater discharge. The Nestucca is considered a premier fishing stream for salmon and steelhead. Total Maximum Daily Loads (TMDL) were established by DEQ for bacteria and temperature in 2002. The permit reflects the limits established through the TMDL process.

4.2 Mixing Zone Analysis

Federal regulations and Oregon Administrative Rules allow DEQ to suspend all or part of the water quality standards in small, designated areas around a discharge point. Initial mixing of the wastewater with the receiving stream occurs in these small areas. These are known as “allocated impact zones” or “regulatory mixing zones”. Two mixing zones can be developed for each discharge: 1) The acute mixing zone, also known as the “zone of initial dilution” (ZID), and 2) the chronic mixing zone, usually referred to as “the mixing zone.” The ZID is a small area where acute criteria can be exceeded as long as it does not cause acute toxicity to organisms drifting through it. The mixing zone is an area where acute criteria must be met but chronic criteria can be exceeded. It must be designed to protect the integrity of the entire water body. The applicable rules for Oregon are found in OAR 340-041-0053.

The permit defined mixing zone extends 100 feet out from the diffuser and the ZID is 10 feet. In 1997, the DEQ performed a field study at the discharge point and using the field measurements estimated a conservative dilution of about 24 to 1 at the edge of the mixing zone. Within the zone of initial dilution, the estimated dilution was at least 5 to 1. No changes have occurred at this site since this field study was performed, but at that time the PCJWSA wastewater facility was discharging chlorinated effluent and had not added the disc filters to the facility. The revised permit will include a condition requiring that the diffuser be inspected as the effluent dilution is dependent on the proper functioning of this diffuser.

In addition, in accordance with the DEQ’s 2008 mixing zone IMD, the permit will require a modeling of the known discharge to confirm the above dilutions are representative of this outfall.

The Department’s mixing zone rules provide that water quality standards include temperature thermal plume limitations in accordance with OAR 340-041-0053(d). This section of the rules contains criteria to prevent potential adverse impacts that may result from thermal plumes. Note that the temperature thermal plume limitations that the Department has adopted are similar to the recommendations in the April 2003 EPA Region X temperature guidance. The criteria as they apply to the PCJWSA STP are discussed below:

OAR 340-041-0053(d)(A): Impairment of an active salmonid spawning area where spawning redds are located or likely to be located.

PCJWSA STP discharge: There is no identified salmonid spawning near the outfall location in this segment of the Nestucca River. This segment of the Nestucca River does serve as a migration corridor for salmonids.

OAR 340-041-0053(d)(B): Acute impairment or instantaneous lethality is prevented or minimized by limiting potential fish exposure to temperatures of 32 ºC or more to less than 2 seconds.

PCJWSA STP discharge: Based on temperature data reported with the discharge montoring reports, the maximum effluent temperature at outfall 001 is around 21 ºC.

Thus, the discharge is not expected to cause an acute impairment or instantaneous lethality.

OAR 340-041-0053(d)(C): Thermal shock caused by a sudden increase in water temperature is prevented or minimized by limiting potential fish exposure to temperatures of 25ºC or more to less than 5% of the cross-section of 100% of the 7Q10 flow of the waterbody.

PCJWSA STP discharge: The reported temperature of this effluent has not exceeded 25ºC.

OAR 340-041-0053(d)(D): Unless ambient temperature is 21 ºC or greater, migration blockage is prevented or minimized by limiting potential fish exposure to temperatures of 21 ºC or more to less than 25% of the cross-section of 100% of the 7Q10 flow of the waterbody.

PCJWSA STP discharge: Based on information provided in the permit application and the DMRs, the effluent temperatures should never be such that they would cause migration blockage.

Thus, the analysis indicates that the discharge from the PCJWSA STP meets the temperature thermal plume limitations in OAR 340-041-0053(d).

5.0 PERMIT LIMITS

There are two categories of effluent limits for NPDES permits: Technology-based effluent limits (TBEL) and Water quality-based effluent limits (WQBEL).

Technology-based effluent limits define a minimum level of treatment using readily-available technology. In the case of domestic wastewater treatment facilities, federal technology-based effluent limits address biochemical oxygen demand (BOD5) and total suspended solids (TSS) concentrations and removal efficiency as well as pH.

The minimum treatment levels referred to above are the secondary treatment standards established by EPA for domestic wastewater treatment facilities (found in 40 CFR Part 133). In general, domestic facilities must achieve biochemical oxygen demand (BOD5) and suspended solids (TSS) monthly average concentrations of 30 mg/L and weekly average concentrations of 45 mg/L. In addition, a minimum removal efficiency of 85 percent is required of domestic dischargers for BOD5 and TSS. Finally, the pH must be between 6.0 and 9.0.

Oregon Administrative Rules establish minimum design criteria for domestic treatment facilities. In this portion of the North Coast Basin, the BOD5 and TSS minimum design criteria are monthly average concentrations of 20 mg/L in the low stream flow period and secondary treatment standards in the high stream flow period (OAR 340-041-0235(3)). In addition, there are requirements for disinfection, dilution of oxygen demanding pollutants, and prevention of raw sewage overflows (OAR 340-041-0007(16)).

In contrast, water quality-based effluent limits are developed independent of the available treatment technology and, instead, take into account the quality and quantity of the receiving stream. Water quality-based effluent limits are typically more stringent than technology-based permit limits when the receiving stream is small, is water quality-limited or shows evidence of impairment.

5.1 Existing Permit Limits

Effluent Parameter

Concentration

Mass

Percent Removal

Monthly Ave. lb/day

Weekly Ave lb/day

Daily Maximum lbs

Monthly

Weekly

BOD5

10

15

30

45

60

85%

TSS

10

15

30

45

60

85%

pH

must be between 6.0 and 9.0

A summary of permit monitoring data is included in Appendix A

5.2 Technology-Based Effluent Limits

The federal secondary treatment standards for this facility are:

Effluent Parameter

Concentration

Percent Removal

Monthly

Weekly

BOD5

30

45

85%

TSS

30

45

85%

pH

must be between 6.0 and 9.0

5.3 Water Quality-Based Effluent Limits

Reasonable Potential Analysis

EPA has developed a methodology called Reasonable Potential Analysis (RPA) for determining if there is a reasonable potential for a discharge to cause or contribute to violations of water quality standards. RPA takes into account effluent variability, available dilution (if applicable), receiving stream water quality, aquatic health water quality standards, and human health water quality standards.

DEQ has adopted EPA’s methodology for RPA. If the RPA results indicate that there is a potential for the discharge to cause or contribute to exceedances of water quality standards, the methodology is then used to determine permit limits for the discharge so as to not cause or contribute to violations of water quality standards.

The RPA for the specific parameters are discussed below and the spreadsheets used for the evaluation is attached.

Ammonia

Ammonia is a substance normally found in wastewater. The wastewater treatment processes, particularly aeration and biological treatment, can convert (oxidize) a large portion to nitrate and nitrite, but the treated effluent still contains some ammonia. After discharge, continued ammonia oxidation removes dissolved oxygen from the receiving stream. Un-oxidized ammonia is also a toxic agent and may have to be limited to prevent in-stream toxicity. Ammonia toxicity varies with pH and temperature of the water. Finally, ammonia and other nitrogen compounds are nutrients that can contribute to excessive biological growth that that may cause violations of water quality standards. The problems could manifest as visual or aesthetic impairment or could be the cause of large fluctuations of dissolved oxygen or pH.

Temperature

Water temperatures affect the life cycles of aquatic species and are a critical factor in maintaining and restoring healthy salmonid populations. The purpose of the temperature criteria in OAR 340-041-0028 is to protect designated, temperature sensitive, beneficial uses (including salmonid life cycle stages) from adverse warming caused by human activities.

The PCJWSA discharge was not specifically included in the TMDL temperature allocation summary for point sources in the Nestucca Bay Watershed as revised in November 2006.

The TMDL noted that at the tidally influenced location of this discharge PCJWSA is required to meet a different standard than the wasteload allocations established through the TMDL in that the discharge was limited to “no significant increase above natural background temperature” at the edge of the mixing zone. Realistically the PCJWSA effluent at worst case dilution could be up to over 7 °C above the background temperature and still meet this limitation. Monitoring data provided with the renewal application indicates that the maximum effluent temperatures and the maximum river temperatures were nearly identical.

Effluent temperature monitoring will continue to be required in the permit and may be used for further evaluation of this discharge in the future. Monitoring will be required only during May through October.

pH

The pH is a measure of how acidic or basic a solution is. At a pH of 7.0 s.u. the solution is considered neutral. The purpose of an in-stream water quality pH standard is generally the protection of aquatic life since most aquatic organisms can only tolerate a fairly narrow range around 7.0 s.u.

The North Coast Basin Water Quality Standard for pH is found in OAR 340-041-0235(1)(b) and establishes the allowed in stream range of 6.5 to 8.5 s.u. The proposed permit limits pH to the range 6.1 to 9.0 s.u., which is a slight change from the existing permit limitation. The existing pH limitation of 6.0 to 9.0 s.u. has been applied to the majority of domestic NPDES permittees in the state and is based on Federal secondary treatment standards for wastewater treatment facilities (40 CFR Part 133.102). Within the permittee's mixing zone, the water quality standard for pH does not have to be met. The Department evaluated pH using a spreadsheet that derives the pH at the mixing zone boundary (See Below) to determine the proposed limitation. Mixing with ambient water within the mixing zone will ensure that the pH at the edge of the mixing zone meets the ambient criteria. Therefore, the Department considers the proposed permit limits to be protective of the water quality standard.

Calculation of pH of a mixture of two flows.

Based on the procedure in EPA's DESCON program (EPA, 1988. Technical

Guidance on Supplementary Stream Design Conditions for Steady State

Modeling. USEPA Office of Water, Washington D.C.)

RPA for pH

INPUT

Lower pH

Upper pH

Criteria

Criteria

1. DILUTION FACTOR AT MZ BOUNDARY - (Qe+Qr)/Qe

24

24

2. UPSTREAM/BACKGROUND CHARACTERISTICS

Temperature (deg C):

17.9

17.9

pH:

6.7

7.4

Alkalinity (mg CaCO3/L):

24.8

24.8

3. EFFLUENT CHARACTERISTICS

Temperature (deg C):

18.0

18.0

pH:

6.1

9.0

Alkalinity (mg CaCO3/L):

149.4

149.4

4. APPLICABLE PH CRITERIA

6.5

8.5

OUTPUT

1. IONIZATION CONSTANTS

Upstream/Background pKa:

6.40

6.40

Effluent pKa:

6.40

6.40

2. IONIZATION FRACTIONS

Upstream/Background Ionization Fraction:

0.67

0.91

Effluent Ionization Fraction:

0.34

1.00

3. TOTAL INORGANIC CARBON

Upstream/Background Total Inorganic Carbon (mg CaCO3/L):

37.15

27.28

Effluent Total Inorganic Carbon (mg CaCO3/L):

445.09

149.77

4. CONDITIONS AT MIXING ZONE BOUNDARY

Temperature (deg C):

17.90

17.90

Alkalinity (mg CaCO3/L):

29.78

29.80

Total Inorganic Carbon (mg CaCO3/L):

53.47

32.18

pKa:

6.40

6.40

pH at Mixing Zone Boundary:

6.5

7.5

Is there Reasonable Potential?

No

No

Bacteria

The proposed limits are taken directly from the Nestucca Bay Watershed TMDL. The proposed limits are a monthly geometric mean of 34 E. coli per 100 mL, with no more than 10% of the samples may exceed 110 E. coli per 100 mL. If a single sample exceeds 110 E. coli per 100 mL, then the permittee must examine the previous 9 bacteria samples to see if this limitation has been exceeded.

Regarding the general condition 6 found in Section B of Schedule F in this permit which prohibits overflows from wastewater conveyance systems, the Environmental Quality Commission (EQC) recognizes that it is impossible to design and construct a conveyance system that will prevent overflows under all storm conditions. The applicant is not seeking permit coverage for overflows and the permit does not authorize such discharges. The State of Oregon has determined that all wastewater conveyance systems should be designed to transport storm events up to a specific size to the treatment facility. Therefore, in exercising its enforcement discretion regarding Sanitary Sewer Overflows, the Department will consider the following:

(1) Whether the permittee has conveyance and treatment facilities adequate to prevent overflows except during a storm event greater than the one-in-five-year, 24-hour duration storm from November 1 through May 21 and except during a storm event greater than the one-in-ten-year, 24-hour duration storm from May 22 through October 31. In addition, DEQ will also consider using enforcement discretion for overflows that occur during a storm event less than the one-in-five-year, 24-hour duration storm from November 1 through May 21 if the permittee had separate sanitary and storm sewers on January 10, 1996, had experienced sanitary sewer overflows due to inflow and infiltration problems, and has submitted an acceptable plan to the Department to address these sanitary sewer overflows by January 1, 2010;
(2) Whether the permittee has provided the highest and best practicable treatment and/or control of wastes, activities, and flows and has properly operated the conveyance and treatment facilities;
(3) Whether the permittee has minimized the potential environmental and public health impacts from the overflow; and
(4) Whether the permittee has properly maintained the capacity of the conveyance system.

DEQ will review the permittee’s determination of the one-in-five-year, 24-hour duration winter storm and the one-in-ten year, 24-hour duration summer storm as described above in the permit holder’s facilities plan. In the event that a permit holder reports an overflow event associated with a storm event and DEQ does not have information from the permit holder sufficient to determine whether or not the storm event exceeds storm events as specified in OAR 340-041-0009(6) & (7), DEQ will perform the determination using the information contained in Figure 26 of the 1973 NOAA Atlas 2 entitled “Precipitation-Frequency Atlas of the Western United States, Volume X – Oregon”. This figure is entitled “Isopluvials of 5-yr 24-hr precipitation in tenths of an inch”. The Atlas can be obtained on line at http://hdsc.nws.noaa.gov/hdsc/pfds/other/or_pfds.html , however the file is very large. A scanned version of Figure 26 is available at: http://www.wrcc.dri.edu/pcpnfreq/or5y24.gif . DEQ will compare the information in this figure with rainfall data available from the National Weather Service, or other source as necessary.

5.6 Anti-degradation

DEQ performed an anti-degradation review for this discharge. Permit renewals with the same discharge loadings as the previous permit, as in this case, are not considered to lower water quality from the existing condition. Based on the anti-degradation review (see relevant portions excerpted from that review below), DEQ determined that the proposed discharge complies with the Anti-degradation Policy for Surface Waters found in OAR 340-041-0026.

ANTIDEGRADATION REVIEW SHEET

FOR A PROPOSED INDIVIDUAL NPDES DISCHARGE

1. What is the name of Surface Water that receives the discharge? Nestucca River

Briefly describe the proposed activity: Renewal of permit to discharge treated sewage.

Is this review for a renewal OR new (circle one) permit application?

Go to Step 2.

2. Is this surface water an Outstanding Resource Water or upstream from an Outstanding Resource Water?

Yes. Go to Step 5.

No. Go to Step 3.

3. Is this surface water a High Quality Water?

Yes. Go to Step 8.

No. Go to Step 4.

8. Will the proposed activity result in a Lowering of Water Quality in the High Quality Water?

Yes. Go to Step 9.

No. Proceed with Permit Application. Applicant should provide basis for conclusion. Go to Step 24.

This conclusion is explained and supported by data and evaluations included within this permit evaluation report and attachments accompanying the proposed NPDES permit renewal. This is an existing discharge and there is no change in their operation. There is no request for a mass load increase.

24. On the basis of the Antidegradation Review, the following is recommended:

__X__ Proceed with Application to Interagency Coordination and Public Comment Phase.

____ Deny Application; return to applicant and provide public notice.

Action Approved

Section: __Northwest Region – WQ Source Control__

Review Prepared By: ___ Lyle Christensen_____________

Phone: ____503-229-5295___________

Date Prepared: ____July 5, 2011_____________

6.0 PERMIT DRAFT DISCUSSION

6.1 Face Page

The face page provides information about the permittee, description of the wastewater, outfall locations, receiving stream information, permit approval authority, and a description of permitted activities. The permittee is authorized to construct, install, modify, or operate a wastewater collection, treatment, control, and disposal system. The permit allows discharge to the Nestucca River within limits set by Schedule A and the following schedules. It prohibits all other discharges.

In accordance with state and federal law, NPDES permits shall be effective for a fixed term not to exceed 5 years. Upon issuance, this permit will be effective for no more than 5 years expiring in 2016.

DEQ does not propose to modify the classifications for the treatment and collection systems. The treatment system is considered a Level III system and the collection system is considered a Level II system.

6.2 Schedule A, Waste Discharge Limits

The proposed effluent limits for the discharge (outfall 001) are as follows:

a. Treated Effluent Outfall 001

(1) Year round

Parameter

Average Effluent

Concentrations

Monthly Weekly

Monthly*

Average

lb/day

Weekly*

Average

lb/day

Daily*

Maximum

lbs

BOD5

10 mg/L 15 mg/L

30

45

60

TSS

10 mg/L 15 mg/L

30

45

60

* Average dry weather design flow to the facility equals .36 MGD. Mass load limits based upon average dry weather design flow to the facility.

(2) Other Parameters (year-round):

Parameters

Limitations

E. coli Bacteria

Shall not exceed 34 organisms per 100 mL monthly geometric mean. No more than 10% of the samples shall exceed 110 organisms per 100 mL. (See Note 1)

pH

Shall be within the range of 6.1 - 9.0

BOD5 and TSS Removal Efficiency

Shall not be less than 85% monthly average for BOD5 and 85% monthly for TSS.

6.3 Schedule B – Minimum Monitoring and Reporting Requirements

6.3.1 Monitoring Requirements

Schedule B describes the minimum monitoring and reporting necessary to demonstrate compliance with the conditions of this permit. The authority to require periodic reporting by permittees is included in ORS 468.065(5). Self-monitoring requirements are the primary means of ensuring that permit limits are being met. Other parameters may also need to be monitored when insufficient data exist to establish a limit, but where there is a potential for a water quality concern.

DEQ has developed a monitoring matrix for commonly monitored parameters that is based on size and complexity of facilities. Proposed monitoring frequencies for all parameters are based on this matrix and, in some cases, may have changed from the current permit.

The permittee is required to have a laboratory Quality Assurance/Quality Control program. DEQ recognizes that some tests do not accurately reflect the performance of a treatment facility due to quality assurance/quality control problems. These tests should not be considered when evaluating the compliance of the facility with the permit limits. Thus, DEQ proposes a statement in the opening paragraph of Schedule B recognizing that some test results may be inaccurate, invalid, or do not adequately represent the facility's performance and should not be used in calculations required by the permit.

The parameters to be monitored, the minimum monitoring frequencies, and sample types are specified in the tables below.

a. Influent

Item or Parameter

Minimum Frequency

Type of Sample

Total Flow

Daily

Measurement

Flow Meter Calibration

Annual

Verification

BOD5

Weekly

24-hour composite

TSS

Weekly

24-hour composite

pH

2/Week

Grab

b. Outfall 001 (Treated Effluent)

Item or Parameter

Minimum Frequency

Type of Sample

BOD5

Weekly

24-hour composite

TSS

Weekly

24-hour composite

E. coli

Weekly

Grab

Temperature

2/Week

Grab

pH

2/Week

Grab

Pounds Discharged (BOD5, TSS)

Weekly

Calculation

Average Percent Removed (BOD5 and TSS)

Monthly

Calculation

UV Radiation Dosage

Daily

Reading or calculation

Nutrients: TKN, NH3-N, NO2+NO3-N,Total Phosphorus

24-hour composite

Dissolved Oxygen

grab

Oil and Grease

grab

Total Dissolved Solids (TDS)

grab

Alkalinity

grab

Note that the parameters without a listed frequency are screening samples that need to be taken at least four times prior to the next renewal application.

c. Biosolids Management

Item or Parameter

Minimum Frequency

Type of Sample

Biosolids analysis including:

Total Solids (% dry wt.)

Volatile solids (% dry wt.)

Biosolids nitrogen for:

NH3-N; NO3-N; & TKN

(% dry wt.)

Phosphorus (% dry wt.)

Potassium (% dry wt.)

pH (standard units)

Sludge metals content for:

As, Cd, Cu, Hg, Mo, Ni, Pb, Se & Zn, measured as total in mg/kg

Annually

Composite sample to be representative of the product to be land applied from the Digester withdrawal line (See Note 3)

Record of locations where biosolids are applied on each DEQ approved site. (Site location maps to be maintained at treatment facility for review upon request by DEQ)

Each Occurrence

Date, volume & locations where biosolids were applied recorded on site location map.

Quantity and type of alkaline product used to stabilize biosolids (when required to meet federal pathogen and vector attraction reduction requirements in 40 CFR 503.32(b)(3) and 40 CFR 503.33(b)(6))

Each occurrence

Measurement

Initial time when solids that received alkaline agent ascended to pH >= 12

Each batch

Date, time, and actual pH measurement (corrected to standard at 25ºC)

2 hours after initial alkaline addition and sustained at pH >= 12

Each batch

Date, time, and actual pH measurement (corrected to standard at 25ºC)

24 hours after initial alkaline addition and pH >= 11.5 was sustained

Each batch

Date, time, and actual pH measurement (corrected to standard at 25ºC)

6.3.2 Reporting Requirements

The proposed NPDES permit requires monitoring results to be submitted monthly. Monthly reports must be submitted by the 15th day of the following month as follows:

a. Monitoring results must be reported on approved forms. The reporting period is the calendar month. Reports must be submitted to the Northwest Region DEQ office by the 15th day of the following month.

b. State monitoring reports must identify the name, certificate classification and grade level of each principal operator designated by the permittee as responsible for supervising the wastewater collection and treatment systems during the reporting period. Monitoring reports must also identify each system classification as found on page one of this permit.

c. Monitoring reports must include a record of the quantity and method of use of all sludge removed from the treatment facility and a record of all applicable equipment breakdowns and bypassing.

In addition, the permittee is required to submit two annual reports to DEQ as follows:

a. The permittee must have a program in place to identify and reduce Inflow and Infiltration into the sewage collection system. A copy of the program must be kept at the wastewater treatment facility for review upon request by the DEQ. An annual Inflow and Infiltration report must be submitted to the DEQ by February 1 each year that includes the following:
(1) Details of activities performed in the previous year to identify and reduce Inflow and Infiltration,
(2) Similar Inflow and Infiltration activities planned for the following year, and
(3) A summary of sanitary sewer overflows that occurred during the previous year.
b. For any year in which biosolids are land applied, a report must be submitted to DEQ by February 19th of the following year that describes solids handling activities for the previous year and includes, but is not limited to, the required information outlined in OAR 340-050-0035(6)(a)-(e).

6.5 Schedule D - Special Conditions

The permit includes six special conditions. Two of the special conditions relate to biosolids and the management of those residual wastes from the treatment system. The first condition requires that the biosolids be managed in accordance with a DEQ approved plan. The second condition provides a reopener to the permit should any of the overriding regulations become more stringent during the time the permit is in force. The third special condition relates the operator certification requirements that must be adhered to under this permit. The Oregon Administrative Rules within Division 49 are summarized within this condition. The fourth special condition requires that a contingency plan be in place in preparation for handling sewage releases that are not permitted under the permit. Spills and unplanned discharges are not expected but it is imperative that if they do occur they are mitigated appropriately. Failure to be prepared for these unexpected events is not excusable. The next special condition requires that the outfall be inspected to verify functionality. Using the in-stream condition findings, modeling of the outfall should be done to confirm assumed dilutions. The final condition just notes that it is the permittee’s responsibility to notify the DEQ Northwest Region office when unusual circumstances arise that may affect the ability of the facility to meet permit compliance

requirements. The specific timeframes required for these notifications are spelled out in Schedule F of the permit.

6.6 Schedule F, NPDES General Conditions

These conditions are standard to all domestic NPDES permits and include language regarding operation and maintenance of facilities, monitoring and record keeping, and reporting requirements. The General Conditions were revised in 2010. A summary of the changes is as follows:

 There are additional citations to the federal Clean Water Act and CFR, including references to standards for sewage sludge use or disposal.
 There is additional language regarding federal penalties.
 Bypass language has been made consistent with the Code of Federal Regulations.
 Overflow language has been modified. Formerly the language stated that overflows in response to the five or ten year event would not violate the permit. Now it states that overflows are prohibited. DEQ will continue to exercise enforcement discretion with respect to overflows consistent with the provisions of the Bacteria Rule (OAR 340-041-0009).
 Reporting requirements regarding overflows have been made more explicit.
 Requirements regarding emergency response and public notification plans have been made more explicit.
 Language pertaining to duty to provide information has been made more explicit.
 Confidentiality of information is addressed.

7.0 NEXT STEPS

7.1 Public Comment Period

The proposed NPDES permit will be made available for public comment for 35 days. Public notice and links to the proposed permit will be posted on DEQ’s website, advertised in newspapers (major sources), and sent to subscribers to DEQ’s pertinent public notice e-mail lists. A Public Hearing will be scheduled if requested by 10 or more people, or by an authorized person representing an organization of at least 10 people. If a public hearing is to be held, then an additional public notice would be published to advertise the public hearing.

7.2 Response to Comments

DEQ will respond to comments received during the comment period. All those providing comment will receive a copy of DEQ’s response. Interested parties may also request a copy of DEQ’s response. Once comments are received and evaluated, DEQ will decide whether to issue the permit as proposed, to make changes to the permit, or to deny the permit. DEQ will notify the permittee of DEQ’s decision.

7.3 Modifications to Permit Evaluation Report and Fact Sheet

Depending on the nature of the comments and any changes made to the permit as result of comments, DEQ may modify this permit evaluation report and fact sheet. DEQ may also choose to update the permit evaluation report and fact sheet through memorandum or addendum. If substantive changes are made to the permit, then an additional round of public comment may occur.

7.4 Issuance

The DEQ mails the finalized, signed permit to the permittee. The permit is effective 20 days from the mailing date.

APPENDIX A: MONITORING DATA SUMMARY

Pacific City JWSA STP

Influent(mg/L)

Effluent

Date

mx day flow

mth flow

BOD

TSS

PE

BOD(mg/L)

%rem

TSS(mg/L)

%rem

E.coli (cfu/100ml)

pH(mx)

pH(min)

7day max temp

Jun-11

0.204

0.149

328

279

2262

10

97

10

97

6

7.4

7.1

18

May-11

0.350

0.149

295

287

2035

13

96

10

97

2

7.8

6.9

13

Apr-11

0.146

0.102

201

254

949

9

95

10

96

2

7.7

7.1

11

Mar-11

0.221

0.116

192

280

1031

10

95

10

96

1

7.7

7.2

10

Feb-11

0.130

0.092

249

243

1060

8

97

7

97

1

7.8

7.1

9

Jan-11

0.283

0.119

203

213

1118

6

97

7

97

2

7.9

7.2

12

Dec-10

0.208

0.118

193

231

1054

8

96

7

97

3

8.1

7.1

14

Nov-10

0.194

0.129

276

258

1648

8

97

5

98

3

7.6

7.2

14

Oct-10

0.181

0.113

349

266

1825

7

98

6

98

3

7.7

7.1

16

Sep-10

0.256

0.145

310

290

2081

7

98

11

97

3

7.9

7

18

Aug-10

0.239

0.186

407

284

3504

9

98

6

98

3

7.8

7

18

Jul-10

0.215

0.143

371

314

2456

10

97

7

98

2

7.6

6.9

18

Jun-10

0.135

0.09

306

266

1275

9

97

7

97

11

7.8

6.9

19

May-10

0.165

0.083

254

258

976

8

97

6

98

2

7.6

7

15

Apr-10

0.136

0.0848

224

272

879

7

97

9

96

4

7.6

6.9

13

Mar-10

0.192

0.12

330

332

1833

10

97

10

97

2

7.7

7

12

Feb-10

0.197

0.119

256

247

1410

5

99

4

99

3

7.4

7

12

Jan-10

0.237

0.135

210

220

1312

9

96

5

98

7

7.5

7

Dec-09

0.146

0.105

250

243

1215

14

94

9

96

7

7.7

6.7

Nov-09

0.205

0.127

254

223

1493

5

98

6

97

5

7.3

6.8

Oct-09

0.160

0.114

251

230

1324

7

97

5

98

3

7.7

7.2

16

Sep-09

0.247

0.133

334

256

2056

10

96

9

96

5

7.9

7.2

18

Aug-09

0.233

0.182

329

281

2772

8

97

8

97

10

8.2

7.2

19

Jul-09

0.318

0.187

388

313

3358

10

97

8

97

11

7.8

7.2

19

Jun-09

0.208

0.141

433

353

2826

7

98

8

98

8

7.6

7.1

18

May-09

0.279

0.132

274

259

1674

8

97

8

97

5

7.5

7

17

Apr-09

0.161

0.114

256

193

1351

8

97

4

97

12

7.6

6.9

Mar-09

0.207

0.13

227

231

1366

7

97

6

97

7

7.5

7

Feb-09

0.161

0.108

252

349

1260

7

97

4

99

3

7.4

6.8

Jan-09

0.552

0.179

144

179

1193

6

96

5

98

1

7.6

7

Dec-08

0.182

0.108

219

257

1095

7

97

5

98

1

7.4

6.9

Nov-08

0.222

0.124

263

244

1510

3

99

6

98

3

7.6

7

Oct-08

0.166

0.113

241

274

1261

5

98

4

99

2

7.8

7.3

17

Sep-08

0.210

0.129

352

286

2102

4

99

6

98

3

8

7.2

19

Aug-08

0.246

0.183

394

338

3337

16

96

9

98

1

7.8

7.2

19

Jul-08

0.301

0.173

280

267

2242

10

97

8

97

2

7.8

7.5

19

Jun-08

0.211

0.128

283

231

1677

7

98

9

97

1

7.8

6.9

18

May-08

0.261

0.118

216

247

1180

8

97

7

97

1

7.9

7.2

18

Apr-08

0.144

0.111

201

211

1033

8

96

10

95

2

7.7

7

Mar-08

0.215

0.13

220

382

1324

8

95

8

97

1

7.9

6.8

Feb-08

0.180

0.123

249

359

1418

6

97

7

98

1

7.8

7

Jan-08

0.195

0.135

205

235

1281

6

97

7

97

1

7.7

7

Dec-07

0.304

0.138

171

176

1092

5

97

4

97

1

7.9

7.3

Nov-07

0.182

0.111

253

289

1300

8

97

7

98

1

7.7

7.2

Oct-07

0.183

0.111

249

281

1279

6

97

8

97

2

8.1

7.3

16

Sep-07

0.248

0.133

278

262

1711

5

98

8

97

4

8

7.1

18

Aug-07

0.211

0.166

322

266

2474

7

98

7

97

2

8

7.5

19

Jul-07

0.234

0.168

260

276

2022

8

88

5

98

1

8

7.4

20

Jun-07

0.201

0.127

302

263

1775

5

98

6

98

1

7.9

7.2

18

May-07

0.236

0.116

273

263

1466

6

98

9

97

3

7.8

7.1

17

Apr-07

0.166

0.115

259

284

1379

8

97

9

97

3

7.4

6.9

Mar-07

0.208

0.139

189

265

1216

2

99

6

98

3

7.5

6.9

Feb-07

0.231

0.133

186

251

1145

5

97

9

96

3

7.3

7

Jan-07

0.248

0.123

215

232

1224

10

95

8

96

3

7.8

7.2

APPENDIX B: REASONABLE POTENTIAL ANALYSIS

( Ammonia)