ASTORIA FACT SHEET And NPDES WASTEWATER DISCHARGE PERMIT EVALUATION

Transcription

1 ASTORIA FACT SHEET And NPDES WASTEWATER DISCHARGE PERMIT EVALUATION Oregon Department of Environmental Quality Northwest Region - Portland Office 2020 SW 4th Ave., Suite 400, Portland, OR Telephone: (503) & FAX File Number: 3924 Permit Number: Permit Application Number: Receiving Stream: Columbia River (River Mile 18.0) Stream Location; Clatsop County Permit Application Date: September 20,2006 Permittee: City of Astoria 1095 Duane Street Astoria, OR Source Location: Treatment facility is located at the end of 53 rd Street in Astoria, Oregon Source Contact: Ken Cook Public Works Director Telephone Number: Proposed Action: Renewal of a National Pollutant Discharge Elimination System (NPDES) wastewater discharge permit. Permit Writer: Garry L. Sage, EIT WQ-NWR- Source Control Section Telephone Number: Source Categoiy: Major Domestic Treatment System Class: Level II Collection System Class: Level IV

2 Page 2 of 24 TABLE OF CONTENTS PAGE Proposed Changes to This Permit 4 Facility Background 5 Introduction 5 Facility Description 5 Biosolids Management and Utilization 6 Inflow and Infiltration (I&I) 6 Pretreatment 7 Pollutants Discharged 7 Beneficial Use Analysis 9 Receiving Stream Water Quality (WQ) Impacts 9 Mixing Zone Analysis. 9 Total Maximum Daily Loads (TMDLs) for Main Stem Columbia R Temperature Analysis 10 Bacteria 11 Chlorine Toxicity 12 Ammonia Toxicity 13 Dissolved Oxygen Reduction 13 Groundwater 13 ph 13 Toxics Analysis, 14 Permit Histoiy 14 Anti-degradation Review 14 Compliance Histoiy 14 Permit Discussion 15 Face Page 15 Schedule A - Waste Discharge limitations 15 Treated Effluent Discharged at Outfall Discharge Seasons 16 BOD 5 and TSS Concentration and Mass Limits 16 BOD5 and TSS Removal Efficiency (Summer Season) 17 BOD5 and TSS Removal Efficiency (Winter Season) 17 ph Limits 18 Temperature Limits Bacteria 18 Chlorine Residual 19 Ammonia 19 Mixing Zone and Zone of Immediate Dilution 19 CSO Outfalls ( ) 20 Groundwater Protection 20 Schedule B - Minimum Monitoring and Reporting Requirements 20 Influent Sampling 20 Influent Measurement and Sampling 20 Effluent Sampling for Outfall

3 Page 3 of 24 PAGE Measurement & Sampling of Year-Around Effluent Parameters 21 Temperature Measurements (May 22 - October 14) 21 Ambient Metals Testing for the Columbia River 22 CSO Outfall Monitoring (Outfalls ) 22 Discharge Monitoring Report (DMR) Procedures 22 WET Testing. 22 Five Day Reporting of SSOs 22 Schedule C - Compliance Schedules and Conditions 22 Schedule D - Special Conditions Operator Certification Groundwater Whole Effluent Toxicity (WET) Testing Emergency Response and Public Notification Plan Notification Facility Planning to Improve Winter % Removals 24 Schedule-E - Pretreatment 24 Schedule-F - General Conditions 24 Attachments 1. Treatment Facility Design Criteria & Background Information 2. Discharge Monitoring Report Data Summaries 3. BOD 5 and TSS Percentage Removal Analysis 4. Chlorine & Ammonia RPA for Toxicity 5. Chlorine Limits 6. Antibacksliding/Antidegradation Review 7. Designated Beneficial Uses for the Main Stem Columbia River 8. Basin-Specific Criteria (Main Stem Columbia River) 9. Oregon's 2010 Integrated Report Database (WQL Status for Lower Columbia River) 10. Temperature RPA 11. Dissolved Oxygen RPA (Streeter-Phelps DO Model) 12. Columbia River ph, Alkalinity, & Temperature Data 13. phrpa 14. Metals RPA 15. Amended Stipulation & Final Order (ASFO) No. WQMW-NWR Permit Milestones 17. CSO Outfalls ( )

4 Page 4 of 24 Proposed Changes to This Permit Schedule-A 1) Summer season is redefined as May 22 through October 14, and winter season as October 15 through May 21 [based on amended stipulation and final order (ASFO) WQMW-NWR signed on October 29, 2010]. 2) Winter effluent mass loads are increased based on the design average wet weather flow (AWWF) approved by DEQ on December 7, ) Summer season BOD5 and TSS percentage monthly average removal limits are increased to 65% to comply with the federal "significant biological treatment" and "equivalent to secondaiy treatment" definitions. 4) BOD 5 and TSS percentage removals are calculated differently for the months of April-May- June and September-October-November. 5) Interim and final limits for bacteria are listed. Final limits for fecal coliform and enterococci bacteria replace current, interim. coll bacteria limits on or before completion of Schedule-C construction. Final fecal coliform and enterococci limits are added to comply with DEQ's internal management directive (IMD) - "Bacteria Criteria for Marine and Estuarine Waters" (Section 10.0, Table-1). 6) Interim and final limits for chlorine residual are listed subject to Schedule-C for re-construction of the chlorine contact chamber, and the addition of dechlorination and ph monitoring/adjustment facilities. Year-around, final effluent chlorine residual limits for daily maximum and monthly average are more stringent than current chlorine limits. 7) Ammonia limits are removed from the permit per Section 303(d)(4) of the Clean Water Act (CWA); since the Columbia River is not water quality limited (WQL) for ammonia and/or dissolved oxygen. The removal of ammonia limits complies with Oregon's antidegradation rules under OAR An ammonia reasonable potential analysis (RPA) supports the elimination of ammonia limits per compliance with WQBELs. Schedule-B 1) Add calculation for monthly average chlorine residual concentration. 2) Add calculation for monthly average ammonia concentration [ammonia monitoring is retained in renewal permit even though limits are dropped (see above)]. 3) Add calculations for BOD5 and TSS monthly average concentration. 4) Provide one sample each per week for fecal coliform and enterococci bacteria. Calculate monthly median and percent exceeding 43 organisms per 100 ml for fecal coliform bacteria. Calculate monthly geometric mean for enterococci bacteria. 5) Report sewage solids relocation &/or transport events. 6) Reduce temperature monitoring for influent, effluent, and Columbia River maximum temperature to one annual measurement during August for each parameter. 7) Modify "year-around CSO reporting requirements" to comply with ASFO WQMW-NWR language. 8) Drop requirements for measurement of Columbia River salinity and velocity [not needed since mixing zone (MZ) study is complete]. 9) Add ambient testing for Columbia River metals (quarterly for first two years, and semi-annual (winter and summer) for duration of the renewal permit). 10) Annual WET testing per Schedule-D is referenced. 11) Sanitary sewer overflow (SSO) reporting requirements are added. Schedule-C 1) Schedule-C lists a compliance schedule for permittee's reconstruction of the chlorine contact basin, and the addition of dechlorination and ph monitoring/adjustment equipment. Schedule- C complies with DEQ's internal management directive (IMD) for Compliance Schedules in NPDES permits.

5 Page 5 of 24 Schedule-D 1) A groundwater protection clause (Item No. 2) is added. 2) Whole effluent toxicity (WET) testing requirements for discharge to fresh water are updated, and amiual testing is required. 3) Item No. 6 is added to gain additional information on treatment potential for improving winter season BOD5 and TSS percent removal levels. Submittal of an approvable facilities plan is required within 6-months of permit issuance. Schedule-F 1) Schedule-F was extensively revised to comply with recent EPA Region-10 mandated changes. 2) Schedule-F clarifies event reporting for permit violations and wastewater overflows.. Facility Background Introduction The City of Astoria operates a wastewater treatment facility located on the south bank of the Columbia River within city limits (Attachment-1). Wastewater (sewage) is treated and discharged to the Columbia River year-around at river mile 18.0, in accordance with National Pollutant Discharge Elimination System (NPDES) Permit number The current permit for this facility was issued on February 15,2002 and expired on January 31, The Department received a permit renewal application on September 20,2006. A renewal permit is necessary to discharge to state waters pursuant to provisions of Oregon Revised Statutes (ORS) 468B.050 and the Federal Clean Water Act. The Department proposes to renew the permit. Currently the permit is under administrative continuation pending its renewal. Facility Description Astoria's wastewater treatment facility is a 3-cell facultative lagoon design with headworks, chlorine contact chamber, and mechanical aeration that was constructed in 1974 (Attachment-1). The ponds provide a treatment level "equivalent to secondary treatment," per 40 CFR Part Lagoon aeration is designed to reduce effluent BOD5 and ammonia. Chlorine is used for effluent disinfection. Dechlorination and ph adjustment/monitoring equipment are currently not installed at this facility. The existing chlorine contact basin must be rebuilt to improve bacteria kill to ensure that the facility can meet proposed limits for fecal coliform and enterococci bacteria (see compliance Schedule-C). The engineer who designed the facility determined the design average dry weather flow (ADWF). It is the estimated maximum daily average dry weather flow (May 1 to October 31) at which the design engineer expects the treatment facility to consistently meet all effluent limits. Diy weather flows do not include the high levels of infiltration and inflow (I&I) that are associated with Oregon winters on the west side of the Cascade Mountains. Therefore, the design ADWF is used mostly to estimate how much treatment capacity there is for organic loads. For this facility, the design ADWF = 4.2 million gallons per day (MGD). The current actual average dry weather, monthly influent flow (May 1 to October 31) for Years was 2.2

6 Page 6 of 24 MGD (Attachment-2). The peak month dry weather influent flow over the interval May 2005 through July 2010 was 12.0 MGD (October 2009). Currently, this facility operates at 52% of its organic treatment capacity. During winter season for Years , the average influent monthly facility flow was 6.4 MGD, and the peak monthly influent flow was 19.4 MGD (Attachment-2). For this facility, the design average wet weather flow (AWWF) = 12.6 MGD, and the design peak wet weather flow (PWWF) is approximately 20.0 MGD. Design wet weather flows represent available winter season treatment capacity at this facility. Based on recent treatment performance, this facility is operating at 51% of its winter season average monthly capacity. See the section below on I&I for additional discussion of winter flows, hydraulic capacity, and combined sewer overflows (CSOs). Biosolids Management and Utilization A biosolids management plan (BMP) is currently not required for this source. The City has not removed sewage solids from its lagoon system for many years. Schedule-B, Lb and Note 5 require the City to record any action that results in movement within the treatment facility of sewage solids, and/or removal of sewage solids from the treatment facility. Under this renewal permit, sewage solids may be transported off-site by a licensed hauler for further treatment and disposal at a permitted facility. Should the City decide to produce its own biosolids for disposal, it must develop a Department approvable BMP. A draft BMP must receive a Public Notice prior to its implementation. DEQ requires a separate BMP Public Notice process when the draft BMP is not given Notice in conjunction with the renewal permit. Potential biosolids application sites in Clatsop County are evaluated first. Biosolids sites located outside of Clatsop County must receive a Public Notice that involves residents in the affected counties. All biosolids application sites must meet the site selection criteria set forth in Oregon Administrative Rule (OAR) Schedule-D, Item No. 6 requires a study of the existing treatment facility for improvement of BOD5 and TSS monthly removal efficiencies during winter season. Part of this study must deal with Pond #1 sewage solids storage/removal. Additionally, Pond #1 must be evaluated as a septage receiving and treatment pond connected to the lagoon treatment system. The results of this study will enable DEQ and the permittee to determine the best way to handle sewage solids in the future. Inflow and Infiltration (I&I) The City of Astoria has a veiy old sanitary collection system made up in large part of combined sanitary and storm sewer systems (Attachment-1). Past practice has created a legacy of leaking old, combined sewers subject to overflow during most rain events. More recent construction has focused on sewer separation. Rainfall driven flows in the combined sanitary and storm collection system typically exceed the system capacity with overflows possible at the CSO points shown on Pages 1 and 2 of this draft permit. There are 38 CSO locations with 3 CSO outfalls listed as removed. CSO discharges go either to Young's River or to the Columbia River without treatment. The city is required under Astoria's amended stipulation and final order (ASFO) WQMW-NWR to continue separating its sanitary sewers from storm water flows. Considerable

7 Page 7 of 24 construction has already occurred to remove storm water from the sanitaiy system. Under the ASFO, the City has committed to a long term construction program that will reduce the number of CSO points and the quantity of flow released at each CSO location. The City has determined that it will cost approximately $39 million in 2010 dollars to construct the facilities needed to meet the level of control required by the ASFO. CSO discharge points on Young's Bay and in the embayment area adjacent to the Alderbrook residential neighborhood are required to achieve a level of control subject to a 5-year return winter storm event and a 10-year return summer storm. All other CSO discharges points to the Columbia River shipping channel are required to achieve a 2- year return summer storm and on average a six-in-a-winter storm level of control. The proposed level of CSO control should reduce the current volume of CSO discharges by approximately 96% in a typical rainfall year. Pretreatment Based on Astoria's population and lack of significant industrial sources, a pretreatment program is not needed at this time to protect influent quality. Under the current permit (Schedule-C, Condition No. 3) an Industrial Waste Survey was completed. The survey determined that there are no industrial sources. A pretreatment program is not required at this time. Pollutants Discharged Current Permit. The current permit allows the City of Astoria to discharge treated effluent from its wastewater treatment facility at Outfall 039 year-around. The current permit sets limits on the following pollutants: Five-day biochemical oxygen demand (BOD5) and total suspended solids (TSS); E. coli bacteria (daily maximum and monthly average); chlorine residual (daily maximum and monthly average); ph (maximum and minimum); ammonia (daily maximum and monthly average); effluent temperature (7-day mean maximum), daily maximum heat load, average monthly heat load; and pollutant removal efficiency for BOD 5 and TSS. Proposed Permit. The proposed permit regulates most of the same pollutants with the following exceptions/changes: 1. The percentage removal efficiencies 1 for summer season BOD 5 and TSS increase from 35% to 65% to comply with minimum "equivalent to secondaiy treatment" standards; 2. Winter mass loads for BOD5 and TSS are increased based on the Department's approval of the design average wet weather flow (AWWF) for this facility; 3. Chlorine residual limits 2 (maximum daily and average monthly) are more stringent; 4. E. coli bacteria limits are replaced with fecal coliform and enterococcus bacteria limits (current permit's E. coli limits become proposed interim limits); and 5. Ammonia limits are eliminated from the permit, however, monitoring requirements are retained in Schedule-B. Footnotes: Percentage Removal. A review of past Astoria permits found that the NPDES permit issued on January 13, 1993 (expired June 30, 1997) contained no percentage removal limits for BOD 5 and TSS. The lack of removal limits was apparently the result of pervasive CSO overflows throughout the combined sanitaiy system that could not be readily quantized for flow volume or

8 Page 8 of 24 concentration. The renewal permit issued on February 15, 2002 (expired on January 31, 2007) included year-around 35% removal limits for BOD5 and TSS. The 35% removal limits for summer season are inadequate (see permit Schedule-A, Note 4 for a detailed explanation). The proposed summer season, percentage removal limits in Schedule-A are more stringent. Limits are increased to 65% to achieve the "equivalent to secondaiy treatment" level for this type of treatment facility. Recent Discharge Monitoring Report (DMR) data indicates that these limits can be met by the existing treatment facility (Attachment-3). Winter season removal efficiencies are discussed below under Permit Discussion, BOD5 and TSS Removal Efficiency (Winter Season). CI Limits. Effluent chlorine residual for fresh and salt water was modeled using DEQ's RPA spread sheet for chlorine and ammonia toxicity (Attachment^). Chlorine permit limits (Attachment-5) were established based on discharge monitoring report (DMR) data (Attachment-2), and on worst-case available dilution in the mixing zone. Schedule-C in the proposed permit establishes a 2.5 year process leading to the addition of dechlorination at Astoria's wastewater treatment facility. Within 2.5 years of permit issuance, permittee must complete a remodel of the existing chlorine contact basin to control and reduce chlorine residual in the facility's effluent. Interim permit limits for chlorine residual apply, until construction listed under Schedule-C is completed. When dechlorination is added to this facility, final permit limits will become effective. Bacteria Limits. Fecal coliform and enterococci bacteria limits are proposed in Schedule-A, La (3) for the protection of marine waters and estuarine shellfish growing waters, per OAR (1) (b). Astoria discharges to the Columbia River Estuary at river mile 18.0, where there is a potential for shellfish growing and/or harvest. Currently, shellfish growing and harvesting are not practiced in the vicinity of Astoria's outfall. The proposed permit contains interim limits for E. coli bacteria and final limits for fecal coliform and enterococci bacteria. By note following Schedule-A, La (3), the proposed permit states: * Should bacteria data indicate that the existing chlorine contact chamber can meet final permit limits for fecal coliform and enterococci bacteria prior to completion of Schedule- C construction; DEQ will require immediate implementation of the final bacteria limits. Enterococcus standards apply to all discharges downstream of the western edge of Puget Island at approximately RM 39.0; given rule-based definitions of estuary and recreational waters developed by the Division of State Lands (DSL) and the Department of Land Conservation and Development (DLCD). Astoria discharges to mixed salt and fresh water with an approximate annual average salinity of 10 parts per thousand (ppt); i.e. estuarine waters. These conditions mandate enterococcus bacteria limits for the proposed permit. Schedule-A, Note 10 discusses these limits.

9 Page 9 of 24 When permit limits for fecal coliform and enterococci bacteria become permanent,. coli testing is no longer required (Schedule-B, Lb Note 4). Schedule-A, Notes 9 and 10 list specifics relating to fecal coliform and enterococci bacteria limits. Limits are taken from DEQ's internal management document (IMD) for Bacteria Criteria for Marine and Estuarine Waters (December 30,2010), Table-1. Ammonia Limits. Ammonia limits are listed in the current permit. The Department proposes to eliminate ammonia limits because recent reasonable potential analyses (RPAs) indicate no potential for ammonia toxicity. The Department's RPA spread sheets for ammonia toxicity are contained in Attachment-4. Ammonia DMR data are included in Attachment-2. No reasonable potential for acute or chronic ammonia toxicity is indicated under worst-case conditions. Attachment-6 contains an Antidegradation Review Sheet, and a discussion prepared by the City of Astoria relating to the proposed reduction in ammonia limits. Normally, renewal permit limits cannot be less stringent than current permit limits. In Astoria's case, current ammonia limits are eligible for a reduction because they are not "final limits." The ammonia limits listed in the current permit (issued February 15, 2002) never took effect because mutual agreement and order (MAO) No. WQ/M , Paragraph 8.(b) established interim limits that are still in force. The MAO was signed on the same day as the current permit was issued. The City's argument in Attachment-6 follows the outline in EPA's NPDES Permit Writer's Manual (Exhibit 7-2, P. 7-5, September 2010) for application of antibacksliding requirements. Ammonia limits are based on state standards. Water quality standards for ammonia are attained per the Clean Water Act (CWA) Sections 402(o)(l)/303(d)(4). The Columbia River has no attaimnent problems associated with ammonia or dissolved oxygen per 303(d)(4)(B) (effluent ammonia does not cause a measurable reduction in dissolved oxygen). The proposed elimination of ammonia limits is consistent with DEQ's antidegradation policy. It complies with effluent guidelines and water quality standards, and beneficial uses are not impaired. Beneficial Use Analysis The designated beneficial uses of the main stem Columbia River are listed in Oregon Administrative Rule (OAR), Chapter 340, Division 041, Table 101A (Attachment-7). Beneficial uses include: public and private domestic water supply, industrial water supply, irrigation, livestock watering, fish & aquatic life, wildlife and hunting, fishing, boating, water contact recreation, aesthetic quality, and commercial navigation and transportation. Division 041, Table 101B lists, "Fish Uses Main Stem Columbia River." Fish uses are, "salmon and steelhead migration corridors at 20 C." Further clarification offish use designations is provided in Figures 230A and 230B. Both figures show North Coast Basin, as well as mainstem uses (Attachment-7). Astoria's outfall discharges to the main stem Columbia River with its salmon and steelhead migration corridor. Receiving Stream Water Quality (WO) Impacts Mixing Zone Analysis In September 2008 the City submitted its revised mixing zone (MZ) study. DEQ approved the

10 Page.l0of24 City's study on December 19, The MZ study focused on worst-case, summer season conditions in the Columbia River; i.e. the 7-day average low-flow with a reoccurrence interval of 10-years (7Q10 low-flow). Based on the study, worst-case dilution at 7Q10 low-flow was determined to be approximately H_i at the zone of initial dilution (Z1D) boundary and 36.0 at the MZ boundary. The Department's water quality modeling, reasonable potential analyses (RPAs) for the proposed pennit are based on these dilution values for worst-case conditions. Dilutions are listed in the proposed permit in Schedule-A, La (1); as a quick reference for future permit evaluations. These dilutions are used in Schedule-D, Special Condition No. 3, to set whole effluent toxicity (WET) testing parameters. Total Maximum Daily Loads (TMDLs) for Main Stem Columbia River The main stem Columbia River is subject to TMDLs for dioxin and dissolved gas (OAR , Attachment^). Astoria's discharge is not affected by either TMDL, since it does not contribute to violations of either parameter. Temperature Analysis To protect the beneficial uses of salmon and steelhead migration (Attachment-7, Table 101B), the Columbia River in the vicinity of the outfall must not exceed 20 C, under worst-case, low-flow summer conditions. According to DEQ's 2010 Integrated Report Database (Attachment^), the Columbia River is water quality limited (WQL) for temperature year-around for its entire length in Oregon.* *The temperature determination relative to Astoria appears to be over conservative; i.e. for year-around discharge to an estuary at RM DEQ's current policy is to list the entire river for temperature when violations are discovered at one or more locations far upstream. DEQ's Point Source Thermal Calculator RPA spread sheets (Attachment-10) indicate that there is no reasonable potential for an effluent driven temperature violation at the MZ boundary or for effluent mixed with 25% of the available 7Q10 low flow during summer season. RPAs indicate that Astoria's discharge does not contribute measurably to river warming. Adequate dilution is available in the MZ and river to keep effluent temperature effects within required limits under worst-case summer season conditions. Temperature limits in the current permit are proposed for the renewal permit. Temperature limits cannot be eliminated on the basis of the above negative temperature RPA findings. The antidegradation arguments used to justify the elimination of ammonia limits (Attachment-6) are not applicable to temperature because the receiving waters are WQL for temperature (Attachment^). The CWA Section 303(d)(4)(A) does not allow a limit reduction for non-attainment waters, unless those limits are based on a total maximum daily load (TMDL) or WLA. Astoria's existing temperature limits are not based on a TMDL or WLA; therefore a revision is not allowed. As stated above, the Department proposes to use current temperature limits in the renewal permit. Thermal Plume Requirements Oregon Administrative Rule (OAR) Chapter 340, Division 041 lists temperature control requirements for effluent discharges to waters of the State. The proposed Astoria renewal permit

11 Page 11 of 24 must comply with the following "Thermal Plume" language in OAR (2) (d) Temperature Thermal Plume Limitations. Temperature mixing zones and effluent limits authorized under (12) (b) will be established to prevent or minimize the following adverse effects to salmonids inside the mixing zone: (A) Impairment of an Active Salmonid Spawning Area. This is not a possibility for Astoria's discharge, since there are no spawning beds in the vicinity of Outfall 039. (B) Acute Impairment or Instantaneous Lethality. Acute impairment or instantaneous lethality is prevented or minimized by limiting potential fish exposure to temperatures of 32.0 degrees Celsius (89.6 degrees Fahrenheit) or more to less than 2 seconds, Astoria's discharge temperature never approaches this temperature threshold. (C) Thermal Shock. Thermal shock caused by a sudden increase in water temperature is prevented or minimized by limiting potential fish exposure to temperatures of 25.0 degrees Celsius (77.0 degrees Fahrenheit) or more to less than 5 percent of the cross section of 100 percent of the 7Q10 low flow of the water body. Astoria's discharge has not reached 25.0 C based on DMR data (Attachment-2). MZ dilation provides immediate temperature reduction even under worst-case, low-flow conditions. (D) Migration Blockage. Unless the ambient temperature is 21.0 degrees or greater, migration blockage is prevented or minimized by limiting potential fish exposure to temperatures of 21.0 degrees Celsius (69.8 degrees Fahrenheit) or more to less than 25 percent of the cross section of 100 percent of the 7Q10 low-flow of the water body. Astoria's effluent does not violate this criterion based on the Thermal Calculator runs discussed above. The Columbia River at Outfall 039 is approximately 5 miles wide. Influent and effluent temperature data for this treatment facility (beginning in January 2006) are contained in Attachment-2. Bacteria Bacteria control criteria for Astoria's sewage treatment facility are based on DEQ's IMD, "Bacteria Criteria for Marine and Estuarine Waters." This IMD was issued on December 30,2010. The IMD requires that both fecal coliform and enterococcus bacteria limits be listed in Schedule-A of the permit. The following limits are proposed for fecal coliform bacteria: Fecal Coliform Bacteria. Shall not exceed a median concentration of 14 organisms per 100 ml, and not more than 10% of the samples shall exceed 43 organisms per 100 ml (Schedule-A, La (3)). Schedule-A, Note 9, Fecal Coliform Bacteria states:

12 Page 12 of 24 Limits are measured at the end-of-pipe. These fecal coliform limits are taken from Section 10.0, Table-1 of DEQ's IMD for Bacteria Criteria for Marine and Estuarine Waters (December 30, 2010) per "Suggested Criteria Language for Permit." It is proposed that additional monthly samples may be taken over the number specified in Schedule-B, 1. b of this permit. All samples collected during the month must comply in aggregate to the limits specified in Schedule-A, 1.a (3). The following limits are proposed for enterococci bacteria: Enterococci Bacteria. Shall not exceed a geometric mean concentration of 35 organisms per 100 ml (Schedule-A, La (3)). Schedule-A, Note 10, Enterococci Bacteria states: Limits are measured at the end-of-pipe. If a single sample exceeds a concentration of 35 organisms per 100 ml, then five consecutive re-samples may be taken at four hour intervals beginning within 28 hours after the original sample was taken. If the log mean of the five re-samples is less than or equal to 35 organisms per 100 ml. a violation shall not be triggered. This enterococci limit is taken from Section 10.0, Table-1 of DEQ's IMD for Bacteria Criteria for Marine and Estuarine Waters (December 30, 2010) per "Suggested Criteria Language for Permit." Bacteria limits in the proposed permit are based on the above fecal coliform and enterococci bacteria standards. E. coli bacteria limits from the current permit are retained as interim limits, until Schedule-C construction is completed. Schedule-B, Lb, Note-4 requires monitoring for E. coli,.fecal coliform, and enterococci bacteria at permit issuance. As discussed above, a note at the bottom of Schedule-A, La. (3) provides for the adoption of final bacteria limits upon demonstration that the existing chlorine contact basin can meet final permit limits. Ultimately, proposed final bacteria limits must be met when Schedule-C work is finished. Chlorine Toxicity Astoria's wastewater treatment facility uses chlorine to disinfect its effluent and meet bacterial limits listed in Schedule-A of the proposed renewal permit (see above). Currently, discharged effluent is not dechlorinated to remove unacceptable toxicity, Interim and final chlorine residual concentration limits are listed in Schedule-A, La (3) of the renewal pennit. Interim chlorine limits apply, until Schedule-C work is complete. Chlorine toxicity was evaluated using the Department's RPA spread sheet (Attachment-4). Effluent DMR data for chlorine residual is summarized in Attachment-2 for the interval January 2007 through May The chlorine RPA determined that chlorine is present, year-around at toxic levels in effluent discharged from Astoria's wastewater treatment facility. Chlorine residual limits necessary to control toxicity are listed in Attachment^. The most stringent limits (salt water, summer season) are proposed as year-around chlorine residual limits. Proposed limits for daily maximum and monthly average chlorine residual are listed in Schedule-A, 1,a (3) of the proposed permit; and current chlorine limits are listed as proposed interim limits. The

13 Page 13 of 24 proposed limits are more stringent than the interim (current) chlorine limits. DEQ believes that proposed chlorine limits can be met at this treatment facility once dechlorination equipment is installed per Schedule-C, Ammonia Toxicity Effluent ammonia data are listed in Attachment-2 for the years January 2007 through May As discussed above, the RPA for ammonia (Attachment-4) determined that effluent discharges at Astoria's treatment facility do not cause ammonia toxicity (acute and chronic); respectively in the ZID or MZ. Based on the ammonia RPA, the Department proposes to eliminate ammonia limits from the proposed permit. The elimination of effluent ammonia limits is consistent with the antibacksliding/antidegradation discussion presented above under "Pollutants Discharged," Footnote #4. The complete antidegradation discussion/review is presented in Attachment-6. Continued year-around ammonia monitoring per Schedule-B, Lb is proposed to track treatment facility performance in removing ammonia, and to provide a data base for the next permit renewal cycle. Dissolved Oxygen Reduction The Department's Streeter-Phelps Dissolved Oxygen Model spread sheet was used to investigate dissolved oxygen (DO) levels associated with a summer season discharge under worst-case conditions (Attachnient-11). Source and river temperature data were taken from Attachments-2 & -12. Modeling results indicate that the DO drop in the receiving stream is < mg/l (insignificant) after complete mixing with the effluent discharge. Model results are consistent with the allowed DO reduction for this type of point source discharge. Groundwater Appropriate sections of the Groundwater Prioritization Worksheet are included in the Department's files for this facility. The Permittee's wastewater treatment and disposal system includes impoundments for sewage solids. No biosolids are produced as discussed above. At this facility, sewage solids are stored in lined treatment lagoons that prevent leaching of nutrients to groundwater. This facility poses no risk to groundwater. The proposed permit (Schedule-A, 1. d) requires proper facility operation and maintenance to protect groundwater. Schedule-D, Special Condition No. 2 reiterates that groundwater must be protected. EH DEQ's ph Spread Sheet (Attachment-13) evaluates Astoria's effluent for ph compliance. Columbia River data collected at the Beaver Army Terminal (RM 55) is used to model ambient conditions (Attachment-12), Effluent data is listed in Attachment-2. Based on worst-case, summer low-flow conditions, the Department found no reason to change current ph permit limits. The Department proposes to use current ph limits in the renewal permit [Schedule-A, 1.a (3)]. As part of the Schedule-C work listed in this permit, the city proposes to add ph

14 Page 14 of 24 adjustment/monitoring equipment to its treatment facility. ph adjustment is sometimes needed in late summer season when effluent drops below the permitted daily ph range. Toxics Analysis Attachment-14 contains RPA spread sheets for metals toxicity pertaining to Astoria's effluent. An effluent, metals data summary; and ambient metals data for the Columbia River [Beaver Army Terminal (RM 55)] is also attached. The spread sheet for fresh water toxicity indicates that all metals evaluated have no potential for acute or chronic toxicity under worst-case, summer 7Q10 low-flow discharge conditions. When the RPA is run with the same metals data and a discharge to salt water, copper is flagged with a reasonable potential for acute toxicity. One copper sample used in this analysis (17.1 ug/l) is 36 % greater than the next largest copper datum. If this value is excluded, there is no reasonable potential for acute copper toxicity (salt or fresh water). The proposed permit (Schedule-B) requires continued metals monitoring during the permit term. Metals data will be collected for influent, effluent, and the Columbia River (near Astoria's discharge). The collection of metals data must comply with the criteria and quantitation limits specified in Schedule-B, Note 3. Following two years of metals testing (counted from permit issuance); the Department will re-evaluate metals data by reasonable potential analysis (RPA). DEQ will determine at that time whether the permit should be re-opened and permit limits added (Schedule-B, l.e). Given additional metals data, it will be possible to improve the RPA for metals toxicity at the next permit renewal. As it now stands, there is no significant likelihood that any metal evaluated exerts acute or chronic toxicity under worst-case, low-flow conditions established for Astoria's discharge. PERMIT HISTORY... Anti-degradation Review An Anti-degradation Review was completed with a recommendation to proceed with this permit action. A copy of the review sheet is located in Attachment-6. Compliance History Since the last permit renewal, no treatment facility improvements were made. The sanitaiy collection system, however, was improved to reduce the number and volume of CSO discharges. Emergency power was installed at major pump and lift stations. Overflow weirs in the collection system were raised to retain more sewage during surcharge events. Inline storage facilities were constructed to capture sewage that previously went to CSO outfalls. Considerable storm water (inflow and infiltration) was removed from the sanitaiy collection system with recent construction. The Department signed an amended and stipulated order (ASFO) with the City on October 29, 2010 for continued sanitary sewer improvements (Attachment-15). The City must eliminate by December 1, 2022 untreated CSO discharges, subject to the storm frequencies specified in Paragraph 11.a of the ASFO at all remaining CSO discharge points, consistent with the facilities plan approved by the Department.

15 Page 15 of 24 Since the current permit was issued (February 15, 2002), the facility has experienced permit violations and enforcement actions as follows (see Attachment-16 for a complete listing): DATE 13Sep2002 4Jun Sep Jun2005 3May Jan2008 9Oct Jul Nov2010 ACTION Penalty Demand Notice (PDN) WQM- NWR PDN WQM-NWR PDNWQM-NWR PDN WQM-NWR PDN WQM-NWR PDN WQM-NWR PDN WQM-NWR PDN WQM-NWR Warning letter (WL-WQ-NWR ) LIMIT VIOLATIONS $250 civil penalty for failure to submit a temperature management plan. $3000 civil penalty for failure to complete Phase-1 CSO overflow control projects. $1700 civil penalty for failure to install operational CSO monitoring equipment. $21,300 civil penalty for unsanctioned CSO discharges. $6000 civil penalty for unsanctioned CSO discharges to Youngs Bay. $3750 civil penalty for numerous DMR effluent limit violations. $100 civil penalty for failure to meet interim chlorine residual limit on 18Aug2008. $200 civil penalty for chlorine limit violations. WL for October weekly BOD effluent concentration violation. PERMIT DISCUSSION Face Page The Permittee is authorized to construct, install, modify, or operate a wastewater collection, treatment, control, and disposal system. Permits year-around discharge of treated effluent to the Columbia River at Outfall 039 located at RM Permit lists combined sewer overflow (CSO) points located in the City's collection system (see Attachment-17 for CSOs locations). Discharges from the City's wastewater treatment facility must be within limits set by Schedule-A, and subsequent permit schedules. All other discharges are prohibited. Schedule-A. Waste Discharge limitations Treated Effluent Discharged at Outfall 039 The proposed permit sets limits on effluent discharges from this facility. Limits on effluent discharges to the Columbia River include: 5-day biochemical oxygen demand (BOD5), «Total suspended solids (TSS),

16 Page 16 of 24 o E. coli bacteria (interim limit), Fecal coliform and enterococci bacteria (final limits), ph, Chlorine residual (interim and final), BOD5 and TSS removal efficiency «Effluent temperature 7-day maximum, Maximum daily heat load, and Monthly average heat load. Discharge Seasons It is proposed that summer and winter seasons listed in Schedule-A correspond to the timing established in the City's ASFO for combined sewer overflow control (Schedule-A, Note 1). BODs and TSS Concentration and Mass Limits: Based on main stem Columbia River minimum design criteria listed in OAR (4), wastewater treatment resulting in a monthly average effluent concentration of 20 mg/l for BOD5 and TSS (or equivalent control) must be provided for periods of low stream flow (Attachment-8). A minimum of secondary treatment (or equivalent control) is required for high stream flow. Since Astoria treats its wastewater with a 3-cell facultative lagoon system, "equivalent to secondary treatment" standards apply.' The Department proposes to continue using year-around "equivalent to secondary treatment" standards for this facility. "Equivalent to secondaty treatment" for this facility is defined as a monthly average concentration limit of 30 mg/l for BOD5 and 50 mg/l for TSS (Schedule-A, Note 3). The summer season mass load limits for BOD5 and TSS are based on the facility's design average diy weather flow (ADWF) = 4.2 MGD. and the monthly average BOD5 and TSS concentration limits listed above. Winter season mass loads are based on the design average wet weather flow (AWWF) = 12.6 MGD, and the monthly average BOD 5 and TSS concentration limits. The limits for treated e Parameter BOD 5 TSS ffluent at Outfall 039 (May 22 - Average Effluent Concentrations Monthly 30 mg/l 50 mg/l Weekly 45 mg/l 75 mg/l October 14) are: Monthly Average lb/day Weekly Average lb/day Daily Maximum Lbs Calculations: BOD. (a) 4.2 MGD x 8.34 #/gal x 30 mg/l = 1100 lbs/day monthly average; (b) lbs/day monthly average x lbs/day weekly average; and (c) lbs/day monthly average x 2.0 = 2100 lbs/day daily maximum.

17 Page 17 of 24 TSS (a) (b) (c) 4.2 MGD x 8.34 #/gal x 50 mg/l = 18001bs/dav monthly average; lbs/day monthly average x 1.5 = 2600 lbs/day weekly average; and lbs/day monthly average x lbs/day daily maximum. The limits for treated effluent at Outfall 039 (October 15 - May 21) are: Average Effluent Concentrations Monthly Average Parameter BOD 5 TSS Monthly 30 mg/l 50 mg/l Weekly 45 mg/l 75 mg/l lb/day Weekly Average lb/day Daily Maximum Lbs Calculations: BOD 5 (a) 12.6 MGD x 8.34 #/gal x 30 mg/l = 3200 lbs/day monthly average; (b) lbs/day monthly average x 1.5 = 4700 lbs/dav weekly average; and (c) lbs/day monthly average x 2.0 = 6300 lbs/day daily maximum. TSS (a) (b) (c) 12.6 MGD x 8.34 #/gal x 50 mg/l = 5300 lbs/dav monthly average; lbs/day monthly average x lbs/dav weekly average; and lbs/day monthly average x 2.0 = lbs/day daily maximum. The City of Astoria's current wastewater treatment facility is capable of meeting the above proposed mass load limits based on composite sampling. BOD, and TSS Removal Efficiency (Summer Season) For Astoria's lagoon treatment system, a minimum monthly average percentage removal = 65% for BODs and TSS is proposed (Schedule-A, Note 4). May 22-October 14 Parameter BODs Removal Efficiency TSS Removal Efficiency Limitations BOD5 removal efficiency shall not be less than 65 % monthly average. TSS removal efficiency shall not be less than 65 % monthly average. BOD, and TSS Removal Efficiency (Winter Season) A 35% monthly average removal efficiency is proposed for BOD5 and TSS based on past practice, and the effects of a combined sewer system (Schedule-A, Note 5). Attachment-3 discusses the reasons for maintaining 35% monthly average removal efficiencies for BOD 5 and TSS:

18 Page 18 of 24 A removal efficiency standard of 85% for BOD5 and TSS is established in 40 CFR Part This is "secondary treatment" for POTWs. Trickling filters and facultative lagoons are allowed limits considered "equivalent to secondary treatment" through 40 CFR Part (this rule allows both BOD5 and TSS removal efficiency of 65% as a monthly average). States may further adjust removal efficiency (for either or both BOD5 and TSS) through one of two exception processes. The exception process fox facilities with combined sewers is found in 40 CFR Part 103(a). These limits need to be established on a case-by-case basis. Astoria fits in this categoiy. By rule they should only be applied during wet weather. Calculated removal should be validfor the life of the facility, and only updated if conditions change or the facility is updated. Schedule-D, special condition No. 6 requires a treatment facility evaluation to determine whether there is potential for improving percentage removals at the existing treatment facility. The study is required within 6-months of permit issuance. Based on the facility evaluation, the Department will determine whether "changed conditions" warrant an increase in percentage removals. Proposed winter season removal efficiencies (equal to current % removals) are as follows: October 15-Mav 21 Parameter BOD5 Removal Efficiency TSS Removal Efficiency Limitations BOD5 removal efficiency shall not be less than 35 % monthly average. TSS removal efficiency shall not be less than 35 % monthly average. ph Limits. The proposed pfi limits in Schedule-A are the same as those in the current permit. Temperature Limits. Proposed temperature limits in Schedule-A are the same as those in the current permit. See Schedule-A, Notes 13 and 14 for details on using these limits. Bacteria The proposed permit limits discharges of E. coli, fecal coliform, and enterococci bacteria to waters of the state. Interim E. coli bacteria limits replaced with final fecal coliform and enterococci bacteria limits per Schedule-C completion. Should bacteria testing indicate that the existing chlorine contact chamber can achieve final bacteria limits before Schedule-C work is finished; final bacteria limits will be applied early (note following Schedule-A, La (3)). The permit proposes the following bacteria limits (Schedule-A, Notes 9 & 10). Parameter (Year-around) Limitations E. coli Bacteria (Interim Limits) Shall not exceed 126 organisms per 100 ml monthly geometric mean. No single sample shall exceed 406 organisms per 100 ml. Fecal Coliform Bacteria Shall not exceed a median concentration of 14 organisms per 100 ml; and 10% of the samples shall not exceed 43 organisms per 100 ml.

19 Page 19 of 24 Enterococci Bacteria Shall not exceed a geometric mean concentration of 35 organisms per 100 ml. Interim. coli bacteria limits remain in effect, until Schedule-C construction is completed; or unti DEQ determines that the existing chlorine contact basin can meet the final limits (whichever occurs first). Chlorine Residual Year-around chlorine residual interim and final limits (daily maximum and monthly average) are proposed (Schedule-A, La (3)). Interim limits are taken from-the current permit. Final limits were developed by RPA using the most stringent discharge conditions (see discussion above). The permittee must comply with the interim chlorine limits, until Schedule-C construction is completed. The Schedule-C compliance schedule provides for the design and reconstruction of the chlorine contact basin for enhanced effluent disinfection; and adds dechlorination and ph monitoring/control equipment to comply with final chlorine residual and ph limits. Schedule-A, Note 11 discusses chlorine residual compliance testing. Parameter (Year-around) Chlorine Residual (Interim Permit Limits) Chlorine Residual Limitations The end-of-pipe effluent limits for chlorine are: daily maximum limit ~ 0.3 mg/l and monthly average limit = 0.1 mg/l (Note 7). Shall not exceed 0.11 mg/l daily maximum and 0.04 mg/l monthly average (Notes 8 & in. Ammonia The Department proposes to eliminate ammonia limits from the renewal permit based on recent RPAs (Attachment), and compliance with EPAs antibacksliding/antidegradation requirements (Attachment-6). See DEQ's ammonia antidegradation discussion above under Pollutants Discharged (Footnote #4). Mixing Zone and Zone of Immediate Dilution Mixing Zone: Except as provided for in OAR , no wastes shall be discharged and no activities shall be conducted which violate Water Quality Standards, as adopted in OAR ; except in the following defined mixing zone: The Regulatory Mixing Zone (RMZ) is that portion of the Columbia River contained within a radius extending two hundred (200) feet from the outfall discharge point(s) in all directions. The Zone of Immediate Dilution (ZID) shall be defined as that portion of the allowable mixing zone that is within a twenty (20) foot radius of each outfall discharge point. The Department believes that the mixing zone, as described above, is appropriate for this discharge. Beneficial uses of the receiving stream will be protected, and the mixing zone meets the criteria in rule.

20 Page 20 of 24 CSO Outfalls Permittee must comply with the performance standards for its 38 combined sewer overflow (CSO) outfalls (listed on Pages 1 and 2 of this permit); and with the schedule for attainment thereof, in accordance with the provisions of the amended stipulation and final order (ASFO) WQMW-NWR (Attachment-15) consistent with the control program set forth in the permittee's CSO Facilities Plan. The CSO Facilities Plan is a Long Term Control Plan under the requirements of the United States EPA's Combined Sewer Overflow Control Policy. Attachment-17- shows CSO outfall locations. It is proposed that Schedule-A list the Nine Minimum Controls for operation and maintenance of the combined sewer system, as set forth in EPA's Combined Sewer Overflow Control Policy. The Nine Minimum Controls are applicable to this permit. Groundwater Protection The renewal permit proposes to prohibit all activities at this facility that could cause an adverse impact on the existing or potential beneficial uses of groundwater. Schedule B - Minimum Monitoring and Reporting Requirements The renewal permit proposes that the laboratory used by the permittee to analyze samples have a quality assurance/quality control (QA/QC) program to verify the accuracy of sample analysis. If QA/QC requirements are not met for any analysis, the results shall be included in the report, but not used in calculations required by the proposed permit. When possible, the permittee shall re-sample in a timely manner for parameters failing the QA/QC requirements, analyze the samples, and report the results. In 1988, the Department developed a monitoring matrix for commonly monitored parameters. Proposed monitoring frequencies for all permit parameters are based on this matrix. They correspond to those applied to facilities of similar size and complexity in the state. Proposed monitoring frequencies are unchanged from the current permit. Influent Sampling Influent parameters must be monitored as specified in the permit at the indicated locations. The permit proposes that grab samples, measurements, and composite samples be taken at the headworks just upstream of the Parshall flume. Septage deliveries are sampled after screening at the headworks. All measurements for influent temperature (summer season) and samples for toxics are taken in the same location. Influent Measurement and Sampling: o Total flow (daily measurement, continuous recorder), Flow meter (annual calibration), o BODs and TSS concentration (1 day/week by 24-hour, composite sampler), BOD5 and TSS concentration (monthly average calculation for each), * BOD5 and TSS mass load calculations (weekly and monthly average), «ph (3 days/week by grab sample), and