-O^ DEQ. National Pollutant Discharge Elimination System PERMIT EVALUATION AND FACT SHEET November 12,2003

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1 \ I -O^ DEQ State of Oregon Department of Environmental Quality National Pollutant Discharge Elimination System PERMIT EVALUATION AND FACT SHEET November 12,2003 Oregon Department of Environmental Quality Western Region 750 Front St NE, Suite 120 Salem OR (503) Permittee: Current Permit: Source Information: Source Contact: Proposed Action: Permit Writer: City of McMinnville 230 East Second Street McMinnville, OR File Number: NPDES Permit Number: EPA Reference Number: OR Issue Date: March 23, 1993 Expiration Date: March 31, 1998 McMinnville Water Reclamation Facilities 3500 NE Clearwater Drive McMinnville, Oregon Latitude 45 13' 36"North, Longitude 123 Ron Bittler, Plant Manager Phone: NPDES Major Domestic Permit Renewal Application Number: Date Received: December 31, 1997 Mark E. Hamlin 9' 30" West Phone: , extension 239

2 City of McMinnville NPDES Renewal Evaluation Report INTRODUCTION The City of McMinnville owns and operates a tertiary wastewater treatment facility located in McMinnville, Oregon (see Attachment #1). Municipal wastewater is treated and discharged to the South Yamhill River in accordance with National Pollutant Discharge Elimination System (NPDES) Permit number The NPDES Permit for the facility was issued on March 23, 1993 and expired on March 31, The Department received a renewal application on December 31, The permit shall not be deemed to expire until final action has been taken on the renewal application as per Oregon Administrative Rules (OAR) 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. This permit evaluation report describes the basis and methodology used in developing the permit. This permit is a joint federal and state permit and subject to federal and state regulations. The Clean Water Act, the Code of Federal Regulations, and numerous guidelines of the Environmental Protection Agency provide the federal permit requirements. The Oregon Revised Statutes, Oregon Administrative Rules, and policies and guidelines of the Department of Environmental Quality provide the state permitting requirements. FACILITY DESCRIPTION The treatment facility serves the entire City of McMinnville. No service is currently provided outside the City limits. During the term of the current permit, the City operated a pilot scale project to examine the potential for treatment of leachate from the Riverbend Landfill. The facilities (see Attachment #2) consist of an off-site raw influent pump station and screen, headworks, activated sludge oxidation ditches, secondary clarifiers, tertiary clarifiers, mono-media filters, ultra-violet (UV) disinfection, effluent reaeration and outfall and biosolids processing. The raw sewage pump station contains 5 centrifugal pumps that pump all wastewater received to the headworks. The headworks consists of two influent channels with two mechanically cleaned fine bar screens and one cyclone grit removal unit. Secondary treatment is provided by two selector style oxidation ditches and two 120 foot circular center feed secondary clarifiers. At least 21 MGD can be treated in the secondary system. The plant performs phosphorus removal during the summer with a combination of biological removal and chemical addition and two tertiary clarifiers. Also during the summer, treated effluent is further polished with mono-media filters. Disinfection is performed with UV disinfection with a peak capacity of 32 MGD. Treated and disinfected effluent is reaerated prior to flow measurement and discharge through an outfall line to a diffuser nozzle outfall in the South Yamhill River at river mile 1.0. The facility is unmanned at night, but has 24 hour monitoring of alarms through telemetry through the treatment plant. The facility also has redundant power at the treatment plant and raw sewage pump station. There are standby power generators at many of the lift stations, PAGE 2

3 City of McMinnville NPDES Renewal Evaluation Report Some minor modifications have been made to the facility during this permit cycle. The changes improved biosolids storage and flow through the treatment plant. A supernatant line from the biosolids storage tank to the plant drain system was installed. The influent and effluent gates to the oxidation ditches were automated. Odor control of the biosolids off-gases is performed by a bio-filter. The existing permit identifies the treatment facility ADWF capacity as 5.6 MGD. During the 2002 and 2003 dry seasons, the plant received an average of 2.9 MGD or 52 percent of its hydraulic capacity. The plant's design organic capacity is 8,920 pounds per day. Plant loading frequently exceeds that amount (particularly for total suspended solids in the winter) but the plant does not appear to be organically overloaded at this time. The plant's design AWWF is 11.2 MGD, Monthly average plant flows during the winter are highly weather dependant and have approached the AWWF during some winter months. Peak instantaneous hydraulic capacity is rated at 32.3 MGD based on the headworks capacity. The facility can generally comply with the existing permit limits. All of the permit limit violations have been mass violations due to high storm flows or toxic upsets. In addition, the City still has several raw sewage overflows each year during major storm events. Biosolids Management and Utilization All waste sludge must be managed in accordance with the Department approved Biosolids Management Plan to ensure compliance with the federal biosolids regulations (40 CFR Part 503) and the state rules (OAR ). The permittee's biosolids management plan was originally approved April 23, 1992, A revised plan was submitted to the Department and approved on January 3, An updated management plan was submitted in August 1999 with additions in September 1999 and April 2000, The biosolids consistently meet the vector attraction and Class A pathogen reduction requirements in 40 CFR Part 503. After treatment necessary to comply with vector attraction and pathogen reduction requirements, the Class A biosolids can be sold, given away or beneficially land applied with few additional restrictions. The plan includes site selection criteria for land application of Class B biosolids (should it become necessary or desirable in the future). The site selection criteria include both Yamhill and Polk Counties. The Department is proposing to approve the plan (see Attachment 3), Waste secondary sludge is thickened with two gravity belt thickeners before undergoing autothermal thermophilic aerobic digestion (ATAD) in three ATAD reactors operated in series. Digested sludge is transferred to a 2.8 MG biosolids storage tank. The gravity belt thickeners can be used to thicken the stored biosolids but are not normally used for that purpose. The stored liquid biosolids are pumped to tanker trucks for beneficial land application on farm land as biosolids during the summer. The City uses volatile solids reduction monitoring to demonstrate compliance with vector attraction requirements and detention time and temperature to demonstrate compliance with Class A pathogen reduction requirements, The City must also perform fecal coliform monitoring of the biosolids. The biosolids are then beneficially applied to over 2300 acres on about 50 sites. The City produces approximately 400 metric dry tons of biosolids per year. Biosolids applications generally occur during July through October each year. The City may continue to utilize all previously authorized land application sites. All current sites are located in Yamhill County. Any future land application sites must conform to the site selection criteria in the Biosolids Management Plan and must be located in Yamhill or Polk Counties. PAGE 3

4 City of McMinnville NPDES Renewal Evaluation Report The City conducted semi-annual chemical testing of removed sludge (see Table 1). Testing includes analyses for nutrients and 11 metals. Based on the analyses, there are no known potential impacts from the current land application program. Table 1 - Biosolids Metals Results for June 2003 Parameter Arsenic Cadmium Chromium Copper Lead Mercury Mg/dry Kg 16 < Table 3 Limit 41 mg/kg 39 mp/kg No limit 1500 mg/kg 300 mg/kg 17 mg/kg Parameter Molybdenum Nickel Selenium Silver Zinc Mg/dry Kg < Table 3 Limit No limit 420 mg/kg 100 mg/kg No limit 2800 mg/kg The facility accepts small amounts of septage from local septic pumpers, Inflow and Infiltration (M) During the 2002 and 2003 dry weather periods (May 1 through October 31), the plant's average flow was 2,9 MGD or 52% of the design capacity. The maximum daily flow of 5.6 MGD occurred in May During the 2001/2002 and 2002/2003 wet weather periods (November 1 though April 30), the average flow to the facility was 7.6 MGD or 68% of the design capacity. The maximum daily flow of 27.8 MGD occurred in January Influent flow has equaled the peak capacity during certain wet weather events. Collection system overflows can result from catastrophic failure of the treatment plant or pump station or high flows due to storm events. During the winters of 2001/2002 and 2002/2003, the City experienced storm related overflows from the collection system during 5 months for a total of 3.01 million gallons. This is a substantial reduction in both overflow days and volumes compared with the overflows that occurred before start-up of the new treatment plant. The plant experiences high levels of I/I. The current permit contains Carbonaceous Biochemical Oxygen Demand (CBOD 5 ) and total suspended solids (TSS) removal efficiency limits of 85 percent during dry weather and 65% during wet weather. The City has had no removal efficiency violations and is capable of complying with the limits. The Department is proposing to retain the existing limits. Industrial Pretreatment The City of McMinnville implements an industrial pretreatment program originally approved by the Department October 25, 1992 under the permit for the previous treatment facility. Federal and State pretreatment requirements were included in the NPDES permit for this facility when originally issued. Schedule E, Condition 12, of the current permit requires the City to submit substantial pretreatment program modification requests to the Department for approval. The City submitted a request for modification of its local limits and the Department proposed to approve the modifications on June 30, The City issued a public notice of the proposed modifications and the Department's intent to approve them on August 15, The City notified the Department on October 3, 1998, that it had completed the public review process and did not receive substantial comments or a request for a public hearing. The Department notified the Environmental Protection Agency (EPA), Region 10, on October 13, 1998, of our intent to approve the City's modifications and afforded EPA the requisite thirty (30) days to object to the Department's approval, pursuant to 40 CFR (d). The date for EPA to object to the Department's approval was extended to December 1, EPA did not object to the approval. PAGE 4

5 City of McMinnville NPDES Renewal Evaluation Report The federal pretreatment regulations (cf., 40 CFR 403,18) require that these modifications be incorporated into the City's NPDES permit, Therefore, the Department is modifying the City's NPDES permit to incorporate these pretreatment program modifications as a part of this permit action, The City currently permits 5 industrial users. One permitted user is not considered "significant". One permitted user is a "significant, non-categorical discharger". Three permitted users are non-discharging categorical industries (only one of which is considered "significant"). The City currently has no categorical users discharging to the treatment system. An audit of the City of McMinnville's Industrial Waste Pretreatment program was conducted on May 22-23, 2001 by DEQ. The primary focus of the audit was to evaluate the accuracy of the information provided in previous annual reports and the adequacy of the City's program implementation and industrial user compliance records and files. As a result of the 2001 audit, the Department's report dated May 25, 2001, listed 10 required actions and 4 recommended actions. The City's response dated September 11, 2001, satisfied the Department that the City is addressing all of the required and recommended actions. A number of these actions resulted in the City Council modifying Chapter 13 the City of McMinnville's Municipal Code, Sewer Use Ordinance (SUO) Number 4761 (superceding 4508A) which became effective May 23, These ordinance revisions were initially approved by the Department on February 7, 2002, and finally on August, 2, 2002, after the City's public notification process was complete and no objections were received. The USEPA Region X was provided an opportunity to comment on this substantial pretreatment program modification but chose not to object; therefore, the sewer use revisions to Chapter 13, Ordinance 4761, adopted by the McMinnville on May 23, 2002, are incorporated into this NPDES permit by reference as an amendment to the City's legal authority to administer the pretreatment program. Groundwater Issues The treatment plant is constructed entirely of impervious structures. It is not anticipated that the treatment process and discharge to surface waters will cause groundwater impacts. Schedule A of the proposed permit prohibits adverse impacts to groundwater. A condition in Schedule D states that no groundwater evaluations will be required during this permit cycle. Stormwater Issues General NPDES permits for stormwater are required for wastewater treatment facilities with a design flow of greater than 1 MGD if stormwater is collected and discharge from the plant site. Because this facility discharges stormwater from the plant site, a separate stormwater permit is necessary. This facility has been assigned a separate 1200-Z permit that regulates the discharge of stormwater. Outfalls The current NPDES Permit allows the treatment facility to discharge treated effluent into the South Yamhill River approximately one-half mile east of the plant at River Mile 1.0. However, the Department's GIS tool identifies the discharge location as River Mile 0.3, The renewal permit will include a river mile of 0,3, Treated and disinfected effluent is reaerated prior to flow measurement and discharged through an outfall line to a diffuser nozzle outfall into the South Yamhill River. Fifteen emergency overflow points are identified in the current permit, The proposed permit contains 14 emergency overflow points. Their use is restricted to storm events as allowed under OAR PAGE 5

6 City of McMinnville NPDES Renewal Evaluation Report 0120(13) and (14) and instances of upset as defined in the General Conditions. During the current permit period, the collection system has overflowed numerous times (generally due to high storm flows). Mixing Zone Analysis The Clean Water Act allows for the use of mixing zones, also known as "allocated impact zones", as long as acute toxicity to drifting organisms is prevented and the integrity of the waterbody as a whole is not impaired. Mixing zones allow the initial mixing of waste and receiving water, but are not designed to allow for treatment, The EPA does not have specific regulations pertaining to mixing zones. Each state must adopt its own mixing zone regulations, The Department has adopted the two-number aquatic life criteria and developed mixing zone regulations with respect to that, The regulations are primarily narrative and essentially require the permit writer to use best professional judgment in establishing the size of the mixing zone. There are essentially two allowable mixing zones for each discharge: 1) The acute mixing zone, also known as the zone of initial dilution (ZID), and 2) the chronic mixing zone, referred to as the mixing zone. The acute mixing zone is designed to prevent lethality to organisms passing through the ZID, The chronic mixing zone is designed to protect the integrity of the entire waterbody as a whole. The allowable size of the mixing zone should be based upon the relative size of the discharge to the receiving stream, the beneficial uses of the receiving stream, location of other discharges to the same waterbody, location of drinking water intakes, and other considerations, More specific guidance is available from the EPA regarding criteria used in appropriately sizing a ZID, The Department's mixing zone regulations state the mixing zone must be less than the total stream width as necessary to allow passage offish and other aquatic organisms, Early recommendations regarding the size of the zone of passage originated from the Department of Interior (1968), They recommended a zone of passage of 75 percent of the cross-sectional area and/or volume of flow of the receiving stream. Based on this recommendation, the Department's standard practice is to allow no more than 25 percent of the stream flow for mixing zones. The current permit provides for a mixing zone that consists of that portion of the South Yamhill River contained within a band extending out fifty (50) feet from the left bank (looking downstream) of the river and extending from a point five (5) feet upstream of the outfall to a point one hundred (100) feet downstream from the outfall, The Zone of Immediate Dilution (ZID) is defined as that portion of the mixing zone that is within ten (10) feet of the point of discharge. The Department proposes to retain the existing mixing zone. Receiving Stream Water Quality The City's discharge is to the South Yamhill River at River Mile 0.3. The discharge is within the Willamette basin and Yamhill sub-basin. The designated beneficial uses of the receiving stream are: public and private domestic water supply, industrial water supply, irrigation, livestock watering, anadromous fish passage, salmonid rearing and spawning, resident fish and aquatic life, wildlife and hunting, fishing, boating, water contact recreation, aesthetic quality and hydro Power. The water quality standards for the Willamette Basin (OAR ) were developed to protect the beneficial uses of the basin. The South Yamhill River is included on the Department's List of Water Quality Limited Water Bodies (also called the 303(d) List) as water quality limited for the following parameters: PAGE 6

7 City of McMinnville NPDES Renewal Evaluation Report Kiioril \\'aleih.'il\ South Yamhill River South Yamhill River South Yamhill River K.M. Oto 18,1 Oto 18.1 Oto 18.1 PilI.llllCU.-I Iron Temperature Fecal Coliform Season Year Around Summer Winter/Spring/Fall t HUTU Table 20 Rearing: 17.8 C Geometric Mean of 200, No more than 10%>400 In addition, a Total Maximum Daily Load (TMDL) addressing violations of the ambient criteria for ph was approved by EPA on March 16, 1992, Oregon Administrative Rules (OAR (9)) implements the TMDL by establishing a Waste Load Allocation (WLA) of 0.07 mg/l for total phosphorus. TMDLs for the other water quality limited parameters are currently scheduled to be written in These future TMDLs may assign additional WLAs to this source. Based on the current TMDL schedule, these WLAs would likely be incorporated into the next permit renewal. Iron Issues The Department does not have any information concerning the discharge of iron from this source. The proposed permit requires the City to monitor the effluent for iron monthly for one year after permit issuance. This monitoring will allow the Department to determine if iron in the discharge has a reasonable potential for causing or contributing to water quality standard violations. The Department may require additional monitoring or reopen the permit to include new limits, conditions or requirements if it is determined that this discharge causes or contributes to the violations of the instream iron criteria. Temperature Issues In addition, the temperature standard also includes a requirement of no measurable temperature increase outside the mixing zone in stream segments containing federally listed Threatened and Endangered (T&E) species if the increase would impair the biological integrity of the T&E population, The National Marine Fisheries Service has listed Chinook salmon and Steelhead as Threatened in the Upper Willamette River Evolutionarily Significant Unit (ESU). According to Oregon Department of Fish and Wildlife (ODF&W) fish distribution maps, Chinook salmon and Steelhead use the South Yamhill River in the vicinity of the discharge for rearing and migration. A "measurable increase" is defined as greater than a 0.25 F increase at the edge of the mixing zone (OAR (55)). The Department evaluates potential impact based on the stream's numeric criteria rather than actual stream temperature. Due to poor dilution during much of the summer period, it is likely the discharge causes a measurable increase in stream temperature at certain times. Therefore, the Department requested that the City develop and submit a Temperature Management Plan (TMP) for approval. The City submitted a TMP dated April The proposed TMP includes an estimate of mixing that occurs within the mixing zone. Based on the estimated 2 to 1 dilution in the South Yamhill River, the discharge has a high probability of impacting stream temperature. Fortunately, the effluent temperature is actually lower than the stream temperature during parts of the year (especially during the warm summer months). The permittee currently monitors effluent and stream temperature during the summer, The TMP proposes to expand the stream monitoring period to the critical fall months when salmonids use the South Yamhill River for rearing and migration. The TMP also proposes evaluating thermal inputs from both internal (units of process) and external (industrial dischargers) sources for impacts and potential reductions. The proposed permit will require effluent temperature monitoring on a year-round basis, The Department is scheduled to develop a TMDL by 2007 that will determine the corrective actions necessary to bring this waterbody back into compliance. The TMDL may assign pollutant WLA to this point source discharge. This permit may be reopened to incorporate any WLA. PAGE 7

8 City of McMinnville NPDES Renewal Evaluation Report The TMP proposes that an assessment of the existing system be submitted by December 31, 2004, The report will include the results of the in-plant temperature monitoring and make recommendations for specific short term measures to be implemented to achieve temperature reductions including a schedule for implementation of the improvements, The measures implemented will be limited to those with low costs, minimal adverse effects on plant operations, and a high potential to reduce thermal loading. The City has not fully evaluated alternatives for long term temperature reductions although it has been determined that neither removing the effluent nor cooling the discharge would likely result in significant improvements to water quality. The TMP indicates upstream mitigation measure such as providing shading of tributary streams, restoration of instream water rights, and habitat restoration may be explored as part of the long term strategy. As a participant in the Yamhill Basin Council, the City has been supporting the watershed group through the provision of office space, administrative support, funding, and laboratory assistance. The City will continue to cooperate with the council as they develop long range strategies. Fecal Coliform Issues As stated, fecal bacterial levels exceed the standard during fall, winter and spring but no TMDL has been developed. The NPDES Permit represents the Bacteria Control Management Plan for the City of McMinnville. As long as the discharge remains in compliance with the permit's bacteria limits, the treated effluent discharge will not have a negative impact on the water quality of the South Yamhill River with respect to bacteria, The sewage collection system has experienced raw sewage overflows for many years. The overflows likely contributed to the ambient fecal bacteria violations. Since the start up of the new treatment facility, the overflows have greatly diminished in volume and frequency. However, until the overflows are eliminated, they will continue to contribute to the ambient fecal bacteria violations. The Department is not aware of any other water quality violations that may be attributable to this source, The Whole Effluent Toxicity (WET) test results submitted with the permit application indicated no statistically significant acute or chronic toxicity to any of the three test organisms, The Department is scheduled to develop a TMDL by 2007 that will determine the corrective actions necessary to bring the South Yamhill River back into compliance. The TMDL may assign pollutant WLA to this point source discharge. This permit may be reopened to incorporate any WLA. PERMIT HISTORY Previous Permit Actions The Department issued NPDES Permit # on March 23, Because this was a new facility, this is the only NPDES Permit for this facility. (The City's previous treatment facility was at a different location and had a separate NPDES permit.) When issued, the permit included limitations not to be exceeded upon start up of new treatment facilities required pursuant to Stipulation and Final Order (SFO) WQ-MW-WVR The permit expired on March 31, The initial NPDES Permit was issued for discharge to the South Yamhill River at river mile 1,0. The plant has a design dry weather average flow of 5.6 MGD. The CBODj and TSS limits vary depending upon season and flow. Limits were established for ph (at 6.0 to 9.0), total dissolved solids (500 mg/l) and fecal coliform (200 and 400 colonies per 100 ml monthly average and weekly average, respectively). Ammonia and total phosphorus limits were established for some season and flow scenarios. A CBOD 5 and TSS percent removal of 85% must be achieved during summer and in winter when flows are 8.4 PAGE 8

9 City of McMinnville NPDES Renewal Evaluation Report MGD or less. At other times, the percent removal may be 65%. Chlorine may not be used as a disinfection agent. A mixing zone and Zone of Immediate Dilution (ZID) were established, Fifteen emergency discharge points were identified, The new treatment facilities were placed into service in January 1996, The SFO has not been terminated because additional inflow and infiltration removal requirements have not been completed. In accordance with the new bacteria standard (OAR ( 13)(b)) approved in February 1996, these requirements can be incorporated into the permit. The proposed permit includes these requirements in Schedule C. Therefore, this permit action will include termination of the SFO. The Department received renewal application number on December 31, The permit shall not be deemed to expire until final action has been taken on the renewal application. An Antidegradation Review was completed with a recommendation to proceed with this permit action (see Attachment #4). Current Permit Limits Schedule A contains the effluent limits for the treatment facility. Some limits are dependent upon the season (summer and winter) while others are year-round. The current permit limits are as follows: Outfall 001 -TreatedEffluent (1) May 1 - October 31 when monthly average stream flow is 100 cfs or less: Average Effluent Concentrations Parameter Monthly Weekly CBOD 5 TSS Ammonia-N Total Phosphorus Dissolved Oxygen 5 mg/l 7.5 mg/l 5 mg/l 7.5 mg/l 0.5 mg/l 0.75 mg/l 70 ug/l Monthly Average lb/day Daily average shall not be less than 6.5 mg/l Weekly ' : ''-'Average'::-:: lb/day y;y;yyypailyy ; :yyy : /y Maximum : m:-^m:-. : (2) May 1 - October 31 when monthly average stream flow is greater than 100 cfs but does not exceed 250 cfs: Average Effluent Concentrations Parameter Monthly Weekly CBODs TSS Ammonia-N Total Phosphorus 10 mg/l 15 mg/l 10 mg/l 15 mg/l 3 mg/l 4.5 mg/l Monthly Average lb/day Weekly Average lb/day Daily <fm : Maximum mm^--;mm (3) May 1 -October 31 when monthly average stream flow is greater 250 cfs Average Effluent Concentrations Monthly Average Weekly Average Parameter Monthly Weekly lb/day lb/day CBOD5 10 mg/l 15 mg/l TSS 10 mg/l 15 mg/l Ammonia-N Total Phosphorus 5 mg/l No limit 7.5 mg/l Daily Maximum lbs PAGE 9

10 City of McMinnville NPDES Renewal Evaluation Report CBOD 5 TSS (4) November 1 - April 30 when plant flow is 8,4 MGD or less: Average Effluent Monthly ; Concentrations : ;: 'Average.'"\ :;.:"'y Parameter Monthly Weekly lb/day 25 mg/l 40 mg/l mg/l 45 mg/l 1400 Parameter CBODs TSS Weekly Average lb/day (5) November 1 - April 30 when plant flow is greater than 8.4 MGD: Average Effluent Monthly Concentrations Average Monthly Weekly lb/day 25 mg/l 40 mg/l mg/l 45 mg/l 3600 Weekly Average lb/day Daily Maximum lbs ;vy; : :Daily,y';:;;y Maximum ^m:mg s m:mm: (6) Other Parameters Other parameters (year-round except as noted) Fecal Coliform PH CBOD 5 and TSS Removal Efficiency (May 1-October 31) CBOD 5 and TSS Removal Efficiency (November 1 - April 30) Total Dissolved Solids Limitations Shall not exceed 200 per 100 ml monthly geometric mean nor 400 per 100 ml weekly geometric mean Shall be within the range of 6,0-9,0 Shall not be less than 85% monthly average. Shall not be less than 85% monthly average when monthly average daily influent flow is 8.4 MGD or less. Shall not be less than 65% monthly average when monthly average daily influent flow is greater than 8.4 MGD. Shall not exceed a monthly average of 500 mg/l Schedule A also defines a mixing zone for Outfall 001 and includes requirements concerning the beneficial reuse of reclaimed water and restrictions on discharges from the emergency overflow outfalls. Compliance History This facility was last inspected March 26, 2003 and was found to be operating in compliance with the permit, The Department uses both formal and informal enforcement actions. NON's are informal enforcement actions. Formal enforcement actions include Notice of Permit Violation (NPV), Civil Penalties (CP) and administrative orders (such as the SFO). The only formal enforcement action taken since 1996 was a NPV issued on August 7, 1996 for raw sewage overflows. Some of the violations appear to be due to toxic conditions in the treatment facility resulting from industrial discharges. No penalties have been assessed. The other violations are either considered to be minor and/or have been corrected. Therefore, the Department considers this facility to be in substantial compliance with the terms of the current permit. There is no record of any complaints about this facility. The following Notices of Noncompliance (NON) have been issued for violations documented at this facility since the facility opened in 1996: PAGE 10

11 City of McMinnville NPDES Renewal Evaluation Report Date of Enforcement Action 6/27/1996 6/13/1997 5/17/ /19/ /9/1999 2/15/2000 5/25/2001 6/13/2002 3/6/2003 6/19/2003 Type of Enforcement Action Class 1 NON Class 2 NON Class 2 NON Class 2 NON Class 2 NON Class 2 NON Class 2 NON Class 2 NON Class 3 NON Class 2 NON Description UNAUTHORIZED WQ DISCHARGES EXCEEDING PERMIT DISCHARGE LIMITS EXCEEDING PERMIT DISCHARGE LIMITS EXCEEDING PERMIT DISCHARGE LIMITS EXCEEDING PERMIT DISCHARGE LIMITS EXCEEDING PERMIT DISCHARGE LIMITS MULTIPLE PRETREATMENT PROGRAM VIOLATIONS EXCEEDING PERMIT DISCHARGE LIMITS EXCEEDING PERMIT DISCHARGE LIMITS EXCEEDING PERMIT DISCHARGE LIMITS PERMIT LIMITATIONS Two categories of effluent limitations exist for NPDES permits: 1) Technology based effluent limits, and 2) Water quality based effluent limits. Technology based effluent limits have been established by EPA rules, Technology based effluent limits were established to require a minimum level of treatment for industrial. or municipal sources using available technology. Water quality based effluent limits are designed to be protective of the beneficial uses of the receiving water and are independent of the available treatment technology, In addition, when performing a permit renewal, there are existing permit limits (discussed above). These may be technology-based limits, water quality-based limits, or limits based on best professional judgment. When renewing a permit, the most stringent of technology-based, water quality-based, and existing effluent limits must be applied. Technology-Based Effluent Limits EPA has established secondary treatment standards for domestic wastewater treatment facilities. The standards are found in 40 CFR Part 133. This facility must achieve a biochemical oxygen demand (BOD 5 ) and suspended solids (TSS) monthly average of 30 mg/l and a weekly average of 45 mg/l. The ph must be between 6,0 and 9.0, In addition, the facility must remove at least 85% of the influent BOD s and TSS. Oregon Administrative Rules establish minimum design criteria for domestic treatment facilities.' In the Willamette Basin, the BOD 5 and TSS minimum design criteria is 10 mg/l as a monthly average in the summer period and secondary treatment in the winter period. In addition, there are requirements for disinfection and dilution of oxygen demanding pollutants. Water Quality-Based Effluent Limits Pollutant parameters should be limited if there is a reasonable potential for the discharge to cause or contribute to an excursion above any state water quality criteria or standard. The TMDL approved in 1992 set WLAs for total phosphorus. Future TMDLs may assign additional WLAs to this source to address in-stream iron, temperature or fecal bacteria violations. PAGE 11

12 City of McMinnville NPDES Renewal Evaluation Report In addition, a reasonable potential analysis (RPA) for ammonia, cyanide, metals and phenol was performed by evaluating effluent data in DEQ spreadsheets. The spreadsheet uses acute and chronic water quality criteria, background concentrations and the available dilution. The RPA (see Attachment #5) for ammonia indicated that there is no reasonable potential for the discharge to cause or contribute to an excursion above the water quality criteria for ammonia. The RPA for the other toxics indicated that concentrations of cyanide, lead, mercury, silver and zinc in the effluent could have a reasonable potential to cause an excursion above the state water quality criteria. Primarily, this was caused by few in-stream data gathered by the Department and the detection levels of those tests. In each case, the effluent concentration was near or below the minimum detection level for that parameter. In addition, the upstream background concentrations were actually above the water quality criteria for lead, mercury and silver. Therefore, the Department proposes to include a permit requirement for special monitoring of the effluent using a "clean" sampling method, an "ultra-clean" sampling method, EPA method 1669 or any other method approved by the Department. Monitoring for mercury shall be conducted in accordance with EPA Method The special monitoring must be conducted semi-annually on one day of the three consecutive days of toxics monitoring. After 2 years, the permittee may discontinue special monitoring of the effluent unless otherwise notified in writing by the Department. After special effluent monitoring is complete, the Department will perform a RPA to determine if the discharge has a potential to cause or contribute to an excursion above the state water quality criteria. The Department strongly recommends the City consider performing similar monitoring on the receiving stream. If there is a reasonable potential, the Department may modify the permit as necessary. The Department is currently proposing changes to several toxic criteria. If the basis of the metals criteria are changed in the future (for instance, from total to dissolved or soluble), the proposed permit allows the Department to revise, in writing, the monitoring requirements as appropriate without a formal permit modification. PERMIT DRAFT DISCUSSION The proposed permit limits and conditions are described below. Refer to the proposed permit and the discussion above when reviewing this section. 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. Permits discharge of treated effluent to the South Yamhill River within limits set by Schedule A and the following schedules. All other discharges are prohibited, In accordance with OAR 340, Division 49 all permitted municipal wastewater collection and treatment facilities are to receive a classification based on the size and complexity of the systems. The Department has incorporated the classification of the collection and treatment systems into the NPDES discharge permit. Both treatment and collection systems are considered Class IV systems. Both systems were reevaluated to determine the appropriateness of the current classification for operator certification requirements (see Attachment #6). Both systems remain as Class IV systems. PAGE 12

13 City of McMinnville NPDES Renewal Evaluation Report, Schedule A, Waste Discharge limitations Schedule A contains the effluent limitations proposed for each Outfall. In addition, there is a condition prohibiting adverse impacts on existing or potential beneficial uses of groundwater, Outfall 102 involving the beneficial reuse of reclaimed water and all related conditions have been removed, Outfall Treated Effluent The Department is proposing to retain the existing limits shown above with two exceptions. A new limit on Excess Thermal Load is proposed and minor adjustments to the total phosphorus limits are proposed. BOD and TSS concentration and mass limits Based on the Willamette Basin minimum design criteria, wastewater treatment resulting in a monthly average effluent concentration of 10 mg/l for BODs and TSS must be provided from May 1 through October 31. From November 1 through April 30, a minimum of secondary treatment is required. Secondary treatment in Oregon is defined as monthly average concentration limit of 30 mg/l for BOD5 or 25 mg/l for Carbonaceous Biochemical Oxygen Demand (CBOD5) and 30 mg/l for TSS. The Department is proposing concentration limits at least as stringent as the basin minimum design criteria, Due to water quality concerns in the South Yamhill River, the existing treatment facility was designed to consistently achieve 5 mg/l CBOD5 and TSS during periods of low stream flow in the summer, The facility must comply with the Willamette River Basin minimum design criteria for the remainder of the summer and secondary treatment standards during the winter, The summer mass load limits (monthly and weekly average and daily maximum) for CBOD5 and TSS for the facility are also divided between low stream flow (100 cfs or less) and higher stream flow periods. The mass limits for both flow periods are based on the design ADWF of 5.6 MGD and the monthly average CBOD5 and TSS concentration limits in effect during that period. The winter mass load limits (monthly and weekly average and daily maximum) for CBODj and TSS from the facility are divided between low plant flow (8.4 MGD or less) and higher plant flow periods. The mass limits for the low flow period are based on the design ADWF of 5.6 MGD and the monthly average CBODj and TSS concentration limits. The mass limits for the high flow period are based on the two year, maximum wet weather monthly average daily design flow of MGD and the monthly average CBOD 5 and TSS concentration limits. In accordance with OAR l-0120(9)(a), the daily mass load limits shall not apply on any day that the dailyflowexceeds 11.2 MGD (twice the design ADWF). Neither the summer or winter mass limits have changed from the prior permit. The mass limits during the summer and winter periods of low plant flow are in accordance with OAR l-120(9)(e). For winter periods of high plantflow,the mass limits are in accordance with OAR (9)(f). From May through October when monthly average stream flow is 100 cfs or less, the calculations for CBOD5 and TSS mass load limits are: a) 5.6 MGD x 8,34 lbs/gal x 5 mg/l = 233 (230) lbs/day monthly avg, b) 233 lbs/day monthly avg x 1,5 = 350 lbs/day weekly avg. c) 233 lbs/day monthly avg x 2 = 466 (470) lbs daily maximum From May through October when monthly average stream flow is greater than 100 cfs, the calculations for CBODS and TSS mass load limits are: a) 5.6 MGD x 8.34 lbs/gal x 10 mg/l = 467 (470) lbs/day monthly avg. b) 467 lbs/day monthly avg x 1.5 = 700 lbs/day weekly avg. c) 467 lbs/day monthly avg x 2 = 934 (930) lbs daily maximum PAGE 13

14 City of McMinnville NPDES Renewal Evaluation Report From November through April when monthly average influent flow is 8.4 MGD or less, the calculations for CBOD5 mass load limits are: a) 5.6 MGD x 8.34 lbs/gal x 25 mg/l = 1168 (1200) lbs/day monthly avg. b) 1168 lbs/day monthly avg x 1.5 = 1752 (1800) lbs/day weekly avg. c) 1168 lbs/day monthly avg x2 = 2336 (2300) lbs daily maximum From November through April when monthly average influent flow is 8.4 MGD or less, the calculations for TSS mass load limits are: a) 5.6 MGD x 8.34 lbs/gal x 30 mg/l = 1401 (1400) lbs/day monthly avg. b) 1401 lbs/day monthly avg x (2100) lbs/day weekly avg. c) 1401 lbs/day monthly avg x 2 = 2802 (2800) lbs daily maximum From November through April when monthly average influent flow is greater than 8.4 MGD, the calculations for CBOD5 mass load limits are: a) MGD x 8.34 lbs/gal x 25 mg/l = 3013 (3000) lbs/day monthly avg. b) 3013 lbs/day monthly avg x 1.5 = 4519 (4500) lbs/day weekly avg. c) 3013 lbs/day monthly avg x 2 = 6026 (6000) lbs daily maximum From November through April when monthly average influent flow is greater than 8.4 MGD, the calculations for TSS mass load limits are: a) MGD x 8.34 lbs/gal x 30 mg/l = 3615 (3600) lbs/day monthly avg, b) 3615 lbs/day monthly avg x 1.5 = 5423 (5400) lbs/day weekly avg. c) 3615 lbs/day monthly avg x 2 = 7231 (7200) lbs daily maximum The CBOD5 and TSS mass load limitations are rounded to two significant figures. A review of monitoring data (see Attachment #7) for the last two years indicate the City is generally able to comply with the permit limits. A few violations have occurred during upsets and major storm events. BOD and TSS Percent Removal Efficiency A minimum level of percent removal for BODS and TSS for municipal dischargers is required by the Code of Federal Regulations (CFR) secondary treatment standards (40 CFR, Part 133). However, the permittee can qualify for a lower percentage removal of BOD and TSS if certain conditions can be demonstrated pursuant to 40 CFR (d). To qualify for the special consideration, the permittee must demonstrate that: a) the treatment facility consistently meets or will meet its concentration limits; b) to meet the percent removal limit, the facility would have to meet significantly more stringent concentration limits; and, c) the less concentrated influent wastewater is not due to excessive inflow and infiltration (I/I). The current permit contains CBOD 5 and TSS removal efficiency limits of 85 percent during the summer and during the winter when monthly average plant flows are less than 8.4 MGD. An evaluation of the percent removal that can be achieved at high influent flows was performed on the estimated flow volume after the removal of the inflow sources. The engineering evaluation indicated the attainable percentage removal for BOD is 65 percent and 65 percent for TSS. The City qualified for a lower percentage removal of CBOD5 and TSS, pursuant to 40 CFR (d), by adequately demonstrating that the conditions for a lesser percentage removal exist or will exist in the design life of the treatment facility. PAGE 14

15 City of McMinnville NPDES Renewal Evaluation Report The City conducted a Sewer System Evaluation Study (as a part of their Facility Planning effort) that demonstrated high flows to the treatment facility are not the result of excessive infiltration and inflow as defined in the federal rules. The entire collection system was flow mapped and all sewer system overflow points were identified. They conducted an engineering evaluation of the attainable percent removal for CBOD 5 and TSS at the peak month design flow and all inflow sources were identified. The City can consistently comply with the current percent removal limits. Since start up, there have been no violations of the removal limits, The proposed permit contains the same percent removal efficiency limits as the existing permit, The City is required to implement a specific program reduce wet weather overflows by for identifying and removing inflow. ph The proposed effluent limits for ph remain unchanged at 6.0 to 9.0 for the facility. The Willamette Basin water quality standards for ph are established in OAR (2)(d)(B), The allowed ambient range is 6.5 to 8.5. The proposed permit limits ph to the range 6.0 to 9.0. This limit is in accordance with Federal wastewater treatment guidelines for sewage treatment facilities (in 40 CFR (c)) and is applied to the majority of NPDES permittees in the state. Within the permittee's mixing zone, the water quality standard for ph does not have to be met. It is the Department's belief that mixing with ambient water within the mixing zone will ensure that the ph at the edge of the mixing zone meets the standard, and the Department considers the proposed permit limits to be protective of the water quality standard. Fecal Bacteria The current permit contains limits on fecal coliform bacteria. The limits are 400 organisms/100 ml weekly geometric mean (or log mean) and 200 organisms/100 ml. monthly geometric mean, In January 1996, the fecal bacteria water quality standard was changed and is now based on E. coli bacteria. The proposed limits are a monthly geometric mean of 126 E. coli per 100 ml, with no single sample exceeding 406 E. coli per 100 ml. The new bacteria standard allows that if a single sample exceeds 406 E coli per 100 ml, then the permittee may take five consecutive re-samples. If the log mean of the five re-samples is less than or equal to 126, a violation is not triggered. The re-sampling must be taken at four hour intervals beginning within 28 hours after the original sample was taken. The fecal bacteria effluent limitations are achievable through proper operation and maintenance. Total Chlorine Residual The treatment facility uses ultra-violet light to disinfect the treated wastewater. No chlorine or chlorine compounds may be used for disinfection purposes and no chlorine residual will be allowed in the effluent due to chlorine used for maintenance purposes. Ammonia Ammonia is a substance normally found in wastewater. The wastewater treatment process converts a large portion to nitrate and nitrite but the treated effluent still contains some ammonia. After discharge, the continued process of oxidizing the ammonia removes dissolved oxygen from the ambient water. Water quality based effluent limits for ammonia were established in the previous permit to prevent violations of the instream dissolved oxygen criteria. Unionized ammonia is also a toxic agent and may have to be limited to prevent toxicity. The water outside the boundary of the mixing zone shall be free of materials in concentrations that will cause chronic (sublethal) toxicity while the water outside the ZID must be free of pollutants that will cause acute toxicity. PAGE 15

16 City of McMinnville NPDES Renewal Evaluation Report If ammonia may be discharged at a level which will cause, have the reasonable potential to cause, or contribute to an excursion above any state water quality standard (dissolved oxygen or toxicity), it must be limited by the permit. In order to determine if a permit limit for ammonia is needed based on toxicity, a Reasonable Potential Analysis was performed. According to EPA's 1986 Quality Criteria for Water and OAR , Table 20, toxic concentrations of total ammonia are ph and temperature dependent. The ph of the South Yamhill River ranges up to 7.6 (both summer and winter). Average river temperatures are as high as 23 C in late summer and 12 C in the fall. Salmonids were assumed to be present in the winter but not the summer. Using a DEQ spreadsheet program (see Attachment #5), an analysis was performed to determine if the discharge will cause, have the reasonable potential to cause, or contribute to any excursion above state water quality standard for ammonia. Fifty-one effluent ammonia results from the summer period were reviewed along with five for the winter period. The highest concentrations found were 1.46 mg/l in the summer and mg/l in the winter. Using the estimated dilutions within the mixing zone and ZID, the spreadsheet calculated that there was no reasonable potential for toxicity due to ammonia. The Department has not proposed ammonia limits based on toxicity in this permit. The existing ammonia concentration limits were established for three summer period stream flow scenarios based on dissolved oxygen depletion. When monthly average river flows are equal to or less than 100 cfs, the monthly average concentration limit is 0,5 mg/l ammonia-nitrogen. Between 100 cfs and 250 cfs, the limit is 3 mg/l and when riverflowsexceed 250 cfs, the concentration limit is 5 mg/l. The corresponding mass load limits (monthly and weekly average and daily maximum) for ammonia are also divided between stream flows. The mass limits for all flow scenarios are based on the design ADWF of 5.6 MGD and the monthly average concentration limits in effect at that flow. When monthly average river flows are equal to or less than 100 cfs, the ammonia mass load limit calculations are: a) 5.6 MGD x 8.34 lbs/gal x 0,5 mg/l = 23.4 (23) lbs/day monthly avg. b) 23.4 lbs/day monthly avg x 1.5 = 35,1 (35) lbs/day weekly avg, c) 23.4 lbs/day monthly avg x 2 = 46.8 (47) lbs daily maximum When monthly average river flows are greater than 100 cfs but do not exceed 250 cfs, the ammonia mass load limit calculations are: a) 5.6 MGD x 8.34 lbs/gal x 3.0 mg/l = 140 lbs/day monthly avg. b) 140 lbs/day monthly avg x 1.5 = 210 lbs/day weekly avg. c) 140 lbs/day monthly avg x 2 = 280 lbs daily maximum When monthly average river flows are greater than 250 cfs, the ammonia mass load limit calculations are: a) 5.6 MGD x 8.34 lbs/gal x 5.0 mg/l = (230) lbs/day monthly avg. b) lbs/day monthly avg x 1.5 = 350 lbs/day weekly avg. c) lbs/day monthly avg x 2 = 467 (470) lbs daily maximum The ammonia mass load limitations are rounded to two significant figures. PAGE 16

17 City of McMinnville NPDES Renewal Evaluation Report Phosphorus Limitations Due to water quality standard violations, a Total Maximum Daily Load (TMDL) for the Yamhill River sub-basin was issued. The TMDL prohibits waste discharges that cause the monthly median concentration of total phosphorus to exceed 70 ug/l during low flow periods. Phosphorus is a substance normally found in wastewater. Water quality based effluent limits for phosphorus were established in the previous permit for two of the three summer period stream flow scenarios. In the first scenario, when monthly average riverflowsare equal to or less than 100 cfs, the current permit limits the monthly average total phosphorus to 70 ug/l. As stated, the TMDL prohibits waste discharges that would cause the ambient monthly median concentration of total phosphorus to exceed 70 ug/l. Therefore, the Department proposes to change the limitation slightly so that compliance is based on the monthly median concentration in the discharge. In the second scenario, when monthly average riverflowsare between 100 cfs and 250 cfs, the current permit limits total phosphorus to 9.6 Ibs/day as a monthly average. The permit states the 9,6 lbs/day mass limit may be recalculated upon permit renewal, A quick evaluation determined that a very small mass load increase may be possible based upon improved dilution within the receiving stream. However, such an increase would require increased application fees, findings that the requested mass load increase is in compliance with OAR (3), and would require approval of the Environmental Quality Commission (EQC). In the absence of these conditions, the Department proposes to retain the existing mass limit and the note concerning recalculation upon the next permit renewal. Again, the Department proposes to..change the limitation slightly so that compliance is based on the monthly median mass of phosphorus in the discharge, No phosphorus limits were established for the third summer scenario when riverflowsexceeded 250 cfs nor for the winter period. No other changes from the previous permit are proposed for Outfall 001. Total Dissolved Solids The current permit contains a limit of 500 mg/l for total dissolved solids. The Department proposes to retain this limit in the renewal permit. Excess Thermal Load limit Stream temperatures are generally rising throughout the State of Oregon and many streams violate the applicable temperature standard in the summer. The Department's Antidegradation Policy (OAR (2)) does not allow for increased discharged loads. Furthermore, it is the Department's policy to reverse warming trends as stated in OAR (3)(D)(i). Point source dischargers are required to help stop and reverse the warming trend. In order to prevent further warming, most discharge permits will identify the maximum allowable temperature or thermal load that can be discharged. The permit must also prohibit future increases except as allowed. The Department is proposing to include a limit on Excess Thermal Load in this permit. This is defined as the amount of heat in the discharge above 64 F. It is based on the maximum thermal discharge that is expected to occur during the summer with the existing design flow (5.6 MGD) and effluent temperatures (73.13 degrees F). The thermal load limit was calculated using the weekly average dry weather design (monthly average dry weather design flow times 1.5) and the degrees Fahrenheit that the maximum expected weekly average of daily maximum effluent temperature exceeds the applicable stream temperature standard, as follows: 5.6 DADWF (MGD) x 1,5 x 8.34 #/ga!lon x (73.13 maximum effluent temperature in F - 64 applicable standard in F) x 1 BTU/lb OF x kcals/btu = 160 million kcals/day PAGE 17

18 City of McMinnville NPDES Renewal Evaluation Report The permit may be reopened and the maximum allowable thermal load modified (up or down), when more accurate effluent temperature data becomes available. If the Total Maximum Daily Load (TMDL) for temperature for this sub-basin assigns a Waste Load Allocation (WLA) to this source, this permit may be re-opened to establish new thermal load limits and/or newtemperatureconditions or requirements. Mixing Zone The current permit provides for a mixing zone that consists of that portion of the South Yamhill River contained within a band extending out fifty (50) feet from the left bank (looking downstream) of the river and extending from a point five (5) feet upstream of the outfall to a point one hundred (100) feet downstream from the outfall. The Zone of Immediate Dilution (ZID) is defined as that portion of the mixing zone that is within ten (10) feet of the points of discharge. The Department proposes to retain the existing mixing zone. Emergency Overflow Outfalls 002 through 010 and 012 through 016 The City has experienced numerous raw sewage overflows from the sewage collection system for many years. On April 5, 1993, the City was issued a SFO (see Attachment #8) that requires elimination of overflows due to storm events less than the one-in-five-year, 24-hour duration storm by October 31, Since the start up of the new treatment facility, the City has reduced both volume and frequency of raw sewage overflows by more than 95 percent. The Order was issued prior to a rule modification in January The new rule prohibits raw sewage overflows due to summer storm events less than the one-in-ten-year, 24-hour duration storm. In the winter, raw sewage overflows due to storm events less than the one-in-five-year, 24-hour duration storm are prohibited. Compliance with the winter discharge prohibition must be as soon as practicable and by no later than January 1, The City has submitted a Wet Weather Overflow Management Plan. The plan calls for compliance as soon as practicable and by no later than January 1,2010, The Department concurs with the plan. By this permit action, the Department is proposing to approve the City's Wet Weather Overflow Management Plan and terminate City's SFO. Groundwater Based on the Department's current information, this facility has a low potential for adversely impacting groundwater quality. Therefore, Schedule D of the proposed permit states that no groundwater evaluations will be required during this permit cycle, The permit also includes a condition in Schedule A that prohibits any adverse impact on groundwater quality. Schedule B - Minimum Monitoring and Reporting 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 (5). Self-monitoring requirements are the primary means of ensuring that permit limitations are being met. However, other parameters need to be monitored to collect information when insufficient information exists to establish a limit, but where there is a potential for a water quality concern. In 1988, the Department developed a monitoring matrix for commonly monitored parameters. Proposed monitoring frequencies for all parameters are based on this matrix and, in some cases, may have changed from the current permit. The proposed monitoring frequencies for all parameters correspond to those of facilities of similar size and complexity in the state. The permittee is required to have a laboratory Quality Assurance/Quality Control program. The Department recognizes that some tests do not accurately reflect the performance of a treatment facility PAGE 18

19 City of McMinnville NPDES Renewal Evaluation Report due to quality assurance/quality control problems. These tests should not be considered when evaluating the compliance of the facility with the permit limitations. Thus, the Department is also proposing to include in the opening paragraph of Schedule B a statement recognizing that some test results may be inaccurate, invalid, do not adequately represent the facility's performance and should not be used in calculations required by the permit. Below is a discussion of some of the minimum monitoring requirements contained in the proposed permit: Influent and Outfall 001 (Treated Effluent - ) Daily monitoring of effluent flow and calibration of the effluent flow meter every six months is required in this permit, The requirement to monitor influent flow and calibration of the influent flow meter has been deleted. Monitoring of the influent and effluent for CBOD s and TSS is retained at three times per week. Pounds of CBOD 5 and TSS must be calculated at the same frequency. Federal secondary treatment standards require municipal sources to achieve a specific CBOD 5 and TSS removal efficiency as a monthly average. Reporting of the removal efficiencies is required in the current permit and no changes are proposed. The proposed permit requires monitoring of the effluent for UV Radiation Intensity on a daily basis to confirm consistent performance of the disinfection system. Bacteria monitoring on the discharge has been changed from fecal coliform to E. coli but the frequency has been retained at three times per week. Monitoring for E. coli must be performed in accordance with one of the methods approved by the Department, Monitoring of the influent and effluent for ph has been changed from three times per week to daily, Ammonia monitoring is required both because CBOD 5 replaces BOD 5 and to determine compliance with ammonia limits. Monitoring must be performed on the same samples as CBOD 5 so the frequency is proposed to increase to three per week. Pounds of ammonia must be calculated and reported at the same frequency. Monitoring of the effluent for total phosphorus from May through October has been increased from once per week to twice per week. The pounds of total phosphorus discharged must be calculated at the same frequency. In order to fully characterize the facility's contribution of nutrients to the receiving stream, the Department is proposing to continue monitoring the treated effluent for certain other nutrients. Weekly monitoring of Total Kjeldahl Nitrogen (TKN) and nitrate plus nitrite is proposed for the period from May through October each year, The requirement to monitor the effluent continuously for dissolved oxygen from May through October has been retained. Monitoring the effluent for total dissolved solids (TDS) is necessary to determine compliance with the permit limitation. However, the frequency has been reduced from three times per week to twice per week. Temperature monitoring will be discussed in a later section. The City previously monitored the influent and effluent for 9 metals, cyanide and total phenols semiannually for three consecutive days. The proposed permit requires monitoring the influent and effluent for 11 metals and cyanide semi-annually for three consecutive days. The total phenols monitoring requirement has been deleted, Monitoring results are to be submitted in the annual pretreatment report and are not required to be submitted with the monthly DMR. For the first two years after permit issuance, the City must perform special toxics monitoring on the effluent during one of the three consecutive days of toxics monitoring. The special toxics monitoring PAGE 19

20 City of McMinnville NPDES Renewal Evaluation Report shall be conducted using a "clean" sampling method, an "ultra-clean" sampling method, EPA method 1669 or any other test method approved by the Department with a detection limit of 0.1 ug/l or less. Monitoring for mercury shall be conducted in accordance with EPA Method After two years of this special toxics monitoring, the City may eliminate the special monitoring of the effluent unless otherwise notified by the Department. The Department will base its determination upon the ability of the permittee to consistently comply with the water quality criteria. The Department has required annual whole effluent toxicity (WET) tests using three species in the proposed permit. If the results of the first four tests show that the effluent is not toxic, no further Whole Effluent Toxicity testing will be required during this permit. Whole Effluent Toxicity tests are to be conducted in accordance with EPA test methods and procedural requirements as defined in Schedule D. Biosolids OAR 340, Division 50, "Land Application of Domestic Wastewater Treatment Facility Biosolids, Biosolids Derived Products, and Domestic Septage" requires monitoring and reporting of specific sludge parameters under Section 35. These parameters are identified in Schedule B under "Biosolids Management" and include: Total solids, Volatile solids, Nitrogen, eleven metals (Ag, As, Cd, Cr, Cu, Pb, Hg, Mo, Ni, Se & Zn), Phosphorus, Potassium and ph. In order to demonstrate compliance with vector attraction requirements, the proposed permit requires monitoring of total and volatile solids in the process and the percent reduction achieved by digestion. Monitoring the digestion time, digestion temperature and fecal coliform content in the biosolids is the method used to demonstrate compliance with pathogen reduction requirements. The City must also record of amount of biosolids derived material sold or given away. Many of these are new requirements. Outfalls 002 through 010 and 012 through 016 (Emergency Overflows') The estimated duration and volume of each overflow from the emergency outfalls must be recorded. There is no change in this requirement. Effluent Temperature Monitoring Temperature monitoring of the effluent is required year round, In addition, the permittee will be required to calculate the weekly average of the daily maximum effluent temperatures year round and the weekly average thermal load discharged during the summer. These are new requirements. Receiving Stream The proposed permit requires the City to monitor the South Yamhill River for flow, temperature and dissolved oxygen, These requirements are similar to the previous permit. Reporting The reporting period is the calendar month, Discharge monitoring reports must be submitted to the Department monthly by the 15th day of the following month. The monitoring reports need to identify the principal operators designated by the Permittee to supervise the treatment and collection systems. The reports must also include records concerning application of biosolids and all applicable equipment breakdowns and bypassing. Schedule B of the permit includes the requirement for the submittal of annual reports. The conditions are standard language requirements concerning: Annual report which details progress towards reducing overflow frequency PAGE 20

21 City of McMinnville NPDES Renewal Evaluation Report Annual report of solids handling activities Annual report on temperature monitoring results Schedule C, Compliance Schedules and Conditions The permit contains one compliance condition with a deadline: 1. By no later than December 31, 2004, the permittee must submit to the Department an assessment of the temperature impacts from the treatment system. The final condition requires the permittee to meet the compliance dates established in this schedule or notify the Department within 14 days following any lapsed compliance date. Schedule D - Special Conditions The permit contains eleven special conditions. The requirements include: 1. The Temperature Management Plan is incorporated into this permit and the permittee is required to implement all elements of the Temperature Management Plan. 2. Department has included a limit on thermal load in Schedule A that identifies the currently permitted amount of thermal energy over and above the temperature standard that may be discharged. The Department is proposing to include a prohibition against increasing thermal discharges beyond the currently permitted amount. 3. The Wet Weather Overflow Management Plan (WWOMP) dated December 1998 is approved by this permit action. It is considered a part of, and should be attached to, this permit. A revised WWOMP must be submitted with the next renewal application. By this permit action the Stipulation and Final Order No. WQ-MW-WVR is hereby terminated. 4. Unless otherwise approved in writing by the Department, all inflow sources are to be permanently disconnected from the sanitary sewer system. 5. Schedule D of this permit includes conditions requiring biosolids be managed in accordance with the approved biosolids management plan. Biosolids that do not meet the Class A criteria shall not be sold or given away. 6. The permit may be modified to incorporate changes in federal biosolids standards. 7. The requirements for Whole Effluent Toxicity (WET) testing are specified. 8. All facilities with an average dry weather design flow over 1.0 MGD must include the results of a priority pollutant scan with their application for permit renewal, Schedule D of this permit includes a condition requiring such submittal and specifying the necessary procedures, 9. The permittee must have the facilities supervised by personnel certified by the Department in the operation of treatment and/or collection systems. 10. The permittee must notify the Department of malfunctions. PAGE 21

22 City of McMinnville NPDES Renewal Evaluation Report 11. The permittee shall not be required to perform a hydrogeologic characterization or groundwater monitoring due during the term of this permit, Schedule E - Pretreatment Activities The current permit contains a Schedule E which requires the City to conduct and enforce an industrial waste pretreatment program as approved by the Department and the General Pretreatment Regulations (40 CFR Part 403). The Department is proposing to include similar conditions in the new permit with some minor changes. Schedule F, NPDES General Conditions All NPDES permits issued in the State of Oregon contain certain conditions that remain the same regardless of the type of discharge and the activity causing the discharge, These conditions are called General Conditions, These conditions can be changed or modified only on a statewide basis. The latest edition of the NPDES General Conditions is December 1, 1995 and this edition is included as Schedule F of the draft permit. Section A contains standard conditions which include compliance with the permit, assessment of penalties, mitigation of noncompliance, permit renewal application, enforcement actions, toxic discharges, property rights and referenced rules and statutes. Section B contains requirements for operation and maintenance of the pollution control facilities. This section includes conditions for proper operation and maintenance, duty to halt or reduce activity in order to maintain compliance, bypass of treatment facilities, upset conditions, treatment of single operational events, overflows from wastewater conveyance systems and associated pump stations, public notification of effluent violation or overflow, and disposal of removed substances, Section C contains requirements for monitoring and reporting. This section includes conditions for representative sampling, flow measurement, monitoring procedures, penalties of tampering, reporting of monitoring results, additional monitoring by the permittee, averaging of measurements, retention of records, contents of records, and inspection and entry. Section D contains reporting requirements and includes conditions for reporting planned changes, anticipated noncompliance, permit transfers, progress on compliance schedules, noncompliance which may endanger public health or the environment, other noncompliances, and other information. Section D also contains signatory requirements and the consequences of falsifying reports. Section E contains the definitions used throughout the permit, PERMIT PROCESSING/PUBLIC COMMENT/APPEAL PROCESS The beginning and end date of the public comment period to receive written comments regarding this permit, and the contact name and telephone number are included in the public notice. The permittee is the only party having standing to file a permit appeal. If the Permittee is dissatisfied with the conditions of the permit when issued, they may request a hearing before the EQC or its designated hearing officer, within 20 days of the final permit being mailed, The request for hearing must be sent to the Director of the Department, Any hearing held shall be conducted pursuant to regulations of the Department, PAGE 22

23 fir m i v - W$) v- ;i^ V i"v M - ' 3 & */'K

24 Attachment 2 & <3><D<

25 CITY OF MCMINNVILLE, OREGON Biosolids Management Plan McMinnville Water Reclamation Facility Revision 3,0 September 2003

26 Table of Contents SECTION PAGE Preface Section LO Section 2.0 Section 3.0 Introduction 1.1 General 1.2 Purpose 1.3 Service Area Characteristics Land Use Population Wastewater Collection System 1.4 Future Population and Land Use Projections Wastewater Treatment Facilities 2.1 Wastewater Characteristics 2.2 Wastewater Treatment and Disposal Facilities NPDES Permit Limits Treatment Facilities Headworks Aeration Basins Secondary and Tertiary Clarifiers Filters Disinfection Sludge Treatment and Storage Facility Design Criteria 2.3 Industrial Pretreatment Program Local Limits Industrial Survey 2.4 Septage Receiving Program ,3 3, Septage Volumes Septage Dumping Requirements Solid Treatment Processes General Waste Activated Sludge ATAD Operation ATAD Regulatory Compliance Pathogen Requirements Vector Attraction Reduction Requirements Historic Trace Pollutant Concentrations Typical Biosolid Characteristics Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 PageTC-1

27 Table of Contents SECTION Section 4.0 Section 5.0 Section 6.0 Section 7.0 Biosolids Storage 4.1 Biosolids Storage Contingency Options 5.1 Background 5.2 Emergency Lime Stabilization Sampling Program 6.1 Monitoring Frequencies 6.2 Sampling Program 6.3 Sample Calculation for Volatile Solids Reduction Reporting and Record Keeping Requirements 7.1 Reporting Requirements 7.2 Record Keeping Requirements DEQ Reporting and Record Keeping Requirements EPA Reporting and Record Keeping Requirements PAGE Section Biosolids Utilization Program Program Overview Agronomic Loading Rates Land Application Equipment Land Application Site Inventory Land Application Management Practices Public Notification Site Selection Criteria Appendices Appendix A Appendix B Appendix C Appendix D 1999 Annual Biosolids Report NPDES Permit Certification Statement 1994 Annual Pretreatment Report Appendix E 40 CFR Part 503 Appendix F OAR 340, Division 50 Appendix G Letter from DEQ Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 PageTC-2

28 Table of Contents SECTION List of Tables PAGE Table 1-1 Table 1-2 Table 1-3 Table 1-4 Table 2-1 Table 2-2 Table 2-3 Table 2-4 Table 2-5 Table 2-6 Descriptive Information Existing Wastewater Influent Flow Characteristics Summary of Existing Land Uses Population of the City of McMinnville Projected Influent Flows and Loadings Discharge Limitations Facility Design Criteria Local Limits Significant Industrial Dischargers Approve Septage Haulers Table 3-1 Raw Sludge Flow Balance Table 3-2 Example Time / Temperature Monitoring Data Table 3-3 ATAD Digester Design Criteria Table 3-4 Time and Temperature Guidelines Table 3-5 Biosolids Trace Pollutant Loading Table 3-6, Biosolids Analysis Data ' Table 4-1 Table 6-1 Table 6-2 Figure 2-1 Figure 2-2 Figure 3-1 Figure 3-2 Aerated Biosolids Strage Tank Biosolids Monitoring Program Sample Calcuation List of Figures Process Flow Schematic Facility Site Plan ATAD Site Layout ATAD Monitoring System List of Graphics Graphic 3-1 Graphic 4-1 Graphic 8-1 ATAD Digesters Biosolids Storage Tank and Biofilter Land Application Project Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 PageTC-3

29 Preface As a condition of the City of McMinnville's existing NPDES permit (Permit No ), the City is required to submit a proposed biosolids management plan to assure that the biosolids generated at the facility will comply with Oregon Administrative Rule Chapter 340, Division 50, "Land Application of Domestic Wastewater Treatment Facility Biosolids, Biosolids Derived Products and Domestic Septage." The Water Reclamation Facility became fully operational in late January 1996, which required that a proposed biosolids management plan be submitted by June On May 17,1995, a copy of the City's biosolids management plan was submitted to DEQ. Included in the Appendix of this document is a copy of a letter dated January 3,1996 from Mr, Tom Fisher of the DEQ approving the City's Biosolids Management Plan, The existing NPDES permit (number #101062) expired March 31, This version (Ver. 3.0) contains the expired permit parameters and information, subject to revision with issuance of the new pending permit, The City's new Water Reclamation Facility was not in operation during the preparation of the old plan document, therefore it was only possible to prepare some elements of the biosolids management plan to define "intendedoperation" or "anticipated operation" for new equipment, facilities, and processes. This Revised Version 3.0 of the plan includes greater than three years of actual operational experience and data to support its elements. The City of McMinnville Water Reclamation Facility will produce a bulk biosolids product that is in full compliance with exceptional quality biosolids (Class A) requirements as defined by EPA and DEQ. As stated in the Preamble to 40 CFR 503, EPA believes that if biosolids meet exceptional quality requirements for trace pollutants, pathogen reduction, and vector attraction reduction, prior to land application, then no further controls are needed on the biosolids or the land where the biosolids are applied. EPA's rationale for not applying the general requirements of 40 CFR Part and the management practices of 40 CFR Part is that biosolids meeting exceptional quality requirements have a comparatively higher value, similar to a commercial fertilizer, and should be regulated similarly to other commercial fertilizers. Given that OAR 340, Division 50, has recently (July 1995) been modified to achieve consistency with 40 CFR Part 503, the City of McMinnville has elected to prepare a Biosolids Management Plan that is also consistent with the exceptional quality requirements of 40 CFR Part 503. As such, the City's biosolids management program will be exempt from the general requirements of 40 CFR Part and the management practices of 40 CFR Part In addition, record keeping and reporting requirements for the City's biosolids management program shall be performed in accordance with the exceptional quality biosolids requirements defined in 40 CFR Part 503,17 and 40 CFR Part , respectively. Land application site inventory is included in this plan from previous DEQ approved sites during the City's Class B biosolids program. These sites are listed and remain in inventory as an alternative application program if the City's biosolids fail to achieve the exceptional quality requirements. During the entire seven previous years of operation, the facility has consistently achieved the exceptional quality classification. Biosolids Management Plan Rev. 3.0 September 2003 City of McMinnville, Oregon

30 Section 1,0 Introduction 1.1 GENERAL The City of McMinnville, Oregon, owns, operates and maintains the McMinnville Water Reclamation Facility in McMinnville, Oregon, The Water Reclamation Facility treats wastewater from the City of McMinnville and the treated effluent is discharged to the South Yamhill River. The facility is an advanced tertiary plant that is designed to remove phosphorus and ammonia in addition to conventional pollutants. Descriptive information pertaining to the McMinnville Water Reclamation Facility is presented in Table 1-1, Table 1-1 Descriptive Information McMinnville Water Reclamation Facility Owner Name NPDES Permit Number NPDES File Number Source Contacts Source Address City of McMinnville, Oregon Mr, Ron Bittlcr 503/ Water Reclamation Facility Manager Mr, Ernie Strahm 503/ Operations Superintendent (Biosolids Coordinator) City of McMinnville, Oregon 3500 NE Clearwater Drive McMinnville OR PURPOSE The McMinnville Water Reclamation Facility currently generates approximately 15,000 gallons per day of aerobically digested biosolids that will be beneficially reused on agricultural properties surrounding the City of McMinnville. Design capacity of the Autothermal Thermophilic Aerobic Digestion (ATAD) process is 24,000 gallons per day, The City of McMinnville's biosolids program is managed in accordance with all regulatory requirements for biosolids generation, and disposal, under authorization from the State of Oregon Department of Environmental Quality (DEQ). This Biosolids Management Plan (Plan) describes the quantity, quality and origin of biosolids generated at the McMinnville Water Reclamation Facility. Industrial pretreatment and wastewater treatment processes are reviewed as well as land application practices. The specific objectives of this Plan are: Provide DEQ, US Environmental Protection Agency (EPA) and other interested parties with all required information on the origin and reuse of biosolids from the McMinnville Water Reclamation Facility, Provide land application site and crop management information for biosolids reuse. Biosolids Management Plan Rev. 3,0 September 2003 City of McMinnville, Oregon Page 1-1

31 Section 1.0 Introduction Provide a description of the biosolids monitoring and sampling program. Provide a description of land application site monitoring, record keeping and reporting procedures. 1.3 SERVICE AREA CHARACTERISTICS The City of McMinnville is located in the Yamhill Basin, which consists of a central plain completely surrounded by hills and mountains within the Willamette River Basin, Three sub-basins make up the Yamhill Basin: the South Yamhill River, the North Yamhill River, and the main stem Yamhill River. McMinnville is the largest urban area within the Yamhill Basin, The McMinnville Water Reclamation Facility has an average dry weather flow (ADWF) capacity of 5.6 mgd, and an average wet weather flow (AWWF) capacity of 11.2 mgd (1993 Design Criteria). Table 1-2 summarizes the wastewater characteristics for Table 1-2 Existing Wastewater Influent Flow Characteristics' 1 ' Average Dry Weather Flow (May-October) Average Wet Weather Flow (November-April) Average BODj Average TSS 2.88 mgd 7.35 mgd 185 mg/l 228 mg/l Note: (1) Source: Daily Monitoring Reports (May 2002-April 2003) Land Use Existing land use within the City of McMinnville includes residential (single or multiple-family zones), commercial, industrial and public lands (e.g., schools, recreational areas and governmental facilities). The sewer service area is divided into seven (7) major drainage basins, A summary of the existing land uses for each drainage basin is shown in Table 1-3, Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 1-2

32 Section 1.0 Introduction Table 1-3 Summary of Existing Land Uses (1) (1990 Development) Basin Population Gross Area (acres) Commercial/Industrial (acres) High School 5, Yamhill Airport 674 2, Downtown 3,770 1, Cozine 3,977 2, Michelbook 1,950 1,138 7,6 Fairgrounds 17,841 2, ,4 Totals 10, Notes: (1) Source: City of McMinnvilic Facility Plan, Population The population of the City of McMinnville has, for the most part, grown steadily from a population of 7,656 in 1960 to more than 28,200 today (see Table 1-4), The population figures presented in Table 1-4 represent the certified population count within the McMinnville city limits as recorded at the Portland State University Center for Population Research and Census Wastewater Collection System The City of McMinnville's wastewater collection system consists of a network of interceptor sewers, trunk sewers, lateral lines, manholes, pump stations, and diversion manholes, The system is owned and operated by the City of McMinnville and it includes nearly 85 miles of collection line ranging in diameter from 4 inches to 54 inches, with 8-inch line the most common. Approximately 6 miles are private service lines. There are approximately 6,303 service connections and 1,659 manholes. The existing service encompasses all land within the existing city limits, or approximately 6,250 acres (although McMinnville's west hills are currently unserviceable pending a major trunk line extension). Currently, the ultimate service area is expected to encompass all land within the existing Urban Growth Boundary, or approximately 7,000 acres, Biosolids Management Plan Rev, 3.0 City of McMinnville, Oregon September 2003 Page 1-3

33 Section 1,0 Introduction Year Table 1-4 Population of the City of McMinnville Historical Trends* Population 1,420 7,656 10,125 14,080 15,175 15,460 15,875 16,400 16,350 17,841 18,640 19,125 20,070 20,995 22,140 22,880 23,485 24,265 25,250 26,499 27,500 28,200 Average Annual Growth Rate 1 ' (%) 2.8 3,4 1, , , ,9 4, ,5 * Source: Portland State University Center for Population Research and Census, b Average Annual Growth Rate from previous reporting year. 1.4 FUTURE POPULATION AND LAND USE PROJECTIONS The anticipated year 2020 population projection for the City of McMinnville is estimated to be 38,720, This figure, determined to be acceptable by the Oregon Department of Land Conservation and Development, is based on recent historicfiguresbut does not take long-term historic trending into account; such trending would produce a much higher population projection. Development projections supportive of the 38,720 population figure addresses all types of private and public needs including residential, commercial and industrial needs as well as land necessary to provide for future open space, Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 1-4

34 Section 1.0 Introduction government services, religious uses, natural resources, and schools. The average annual growth rate (AAGR) of McMinnville from 1900 to 1998 was 2.94 percent. Biosolids Management Plan Rev. 3.0 September 2003 City of McMinnville, Oregon Page 1-5

35 Section 2.0 Wastewater Treatment Facilities 2.1 WASTEWATER CHARACTERISTICS The McMinnville Water Reclamation Facility has been designed as a nutrient removal facility for phosphorus and ammonia-nitrogen. The wastewater characteristics used in the process design of the McMinnville Water Reclamation Facility are listed in Table 2-1, Table 2-1 Projected Influent Flows and Loadings Parameter Population 20,660 27,720 37,174 Flow rate (mgd) Dry weather DWADF DWMMADF DWMiMADF DWMDF Wet weather WWADF WWMMADF WWMDF" PFR«3.1 3, ,6 8, , , ,8 21, Average BOD 5 loading (lb/day) 4,958 6,647 8,914 Average TSS loading (lb/day) 4,958 6,647 8,914 Average ammonia-nitrogen loading (lb/day) ,168 Average phosphorus loading (lb/day) Legend: DWADF DWMMADF DWMiMADF DWMDF WWADF WWMMADF WWMDF PFR = Dry weather average daily flow, = Dry weather maximum month average daily flow. = Dry weather minimum month average daily flow. = Dry weather maximum daily flow, = Wet weather average daily flow, - Wet weather maximum month average daily flow, = Wet weather maximum daily flow.* = Peak flow rate.* 2.2 WASTEWATER TREATMENT AND DISPOSAL FACILITIES The McMinnville Water Reclamation Facility has been designed to provide long-term benefits to the water quality and beneficial uses of the Yamhill River. A flow schematic for the solids digestion process of the McMinnville Water Reclamation Facility is shown in Figure 2-1, and a site plan of the facility is shown on Figure 2-2, Biosolids Management Plan Rev, 3.0 City of McMinnville, Oregon September 2003 Page 2-1

36 Section 2.0 Wastewater Treatment Facilities Figure 2-1 Process Flow Schematic Solids Digestion Process Air Compressor Waste Activated Sludge Thickened Sludge Wet Walla Digestion ATAD Transfer Put"!") / / B 030' JS I Stcraga lank Gravity Belt Hosolids Hopper Gravity Belt Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 2-2

37 Section 2.0 Wastewater Treatment Facilities Figure 2-2 Facility Site Plan )<D SE -* c -- z 5 - f/i m i> z W H J! $ n 3 1 "* * 8 q S I I S 1 I K 3 fj 2 5 m r o w r Jl M c «-I ^ T> N (ft O r) r* J n «H 8 Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 2-3

38 Section 2,0 Wastewater Treatment Facilities NPDES Permit Limits The City of McMinnville, Oregon operates and maintains its wastewater collection, conveyance and treatment facilities in accordance with: NPDES Permit Number Issued: March 23,1993 Expires: March 31,1998 The current waste discharge limitations for the McMinnville Water Reclamation Facility are based on dry season (May 1 - October 31) and wet season (November 1 - April 30) conditions, as well as monthly average flows in the South Yamhill River. The most stringent discharge limitations for the McMinnville Water Reclamation Facility are listed in Table 2-2. These limitations are enforceable during the diy season when flow in the South Yamhill River is 100 cubic feet per second (cfs) or less. Table 2-2 Discharge Limitations McMinnville Water Reclamation Facility Parameter CBODj Monthly mg/l 5 Average Effluent Concentrations Weekly mg/l 7,5 Monthly Average lbs/day 230 Weekly Average lbs/day 350 Daily Maximum lbs/day 470 TSS 5 7.S Ammonia-N Total Phosphorous FC/lOOml Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 2-4

39 Section 2,0 Wastewater Treatment Facilities Treatment Facilities The McMinnville Water Reclamation Facility is an activated-sludge secondary treatment plant with a dry weather capacity of 5.6 mgd and a wet weather capacity of 11.2 mgd. Major treatment processes for the McMinnville Water Reclamation Facility include: Headworks with screening and grit removal Oxidation ditch activated sludge Secondary clarification Tertiary clarifiers Filtration Ultraviolet (UV) disinfection WAS thickening Autothermal thermophilic aerobic digestion (ATAD) Aerated biosolids storage tank Biofilter Headworks The headworks includes two mechanical screens; two screening presses; one vortex type grit basin with cyclone classifier; a control room; biosolids storage pumps and air compressor; storage tanks and feed pumps for sodium hydroxide, sodium hypochlorite, alum, and polymer; two gravity belt thickeners; and sludge transfer pumps. The headworks has a total peak flow capacity of 32.3 mgd, and screenings and grit will be removed by dump truck Aeration Basins Two oxidation ditch aeration basins provide both nutrient and BOD removal using biological selector technology. Disc aerators are provided for each basin. The aeration basins provide a total volume of 3.1 mg and 6.4 hours detention time at wet weather average daily flow. Flows greater than approximately 24 mgd bypass the aeration basins in a 30-inch line from the aeration splitter box to the filter effluent box, and is disinfected prior to discharge. The gravity belt thickener filtrate will be returned to the aeration splitter box, Secondary and Tertiary Clarifiers Two 120-foot diameter secondary clarifiers have a capacity of 24 mgd including RAS flow. Mixed liquor is received from the aeration basins and is discharged to two tertiary clarifiers. The 70-foot diameter tertiary clarifiers are of the upflow, solids contact type for chemical precipitation of phosphorus using alum and polymer. The design capacity of the tertiary clarifiers is 13 mgd Filters Prior to disinfection, six filters of the continuous upflow type polish effluent from the tertiary clarifiers. The design capacity of the filters will be 13 mgd. There is a bypass channel around the filters for flows above 13 mgd. Biosolids Management Plan Rev. 3.0 September 2003 City of McMinnville, Oregon Page 2-5

40 Section 2.0 Wastewater Treatment Facilities Disinfection Three UV disinfection channels each consisting of three banks of lamp modules disinfect the effluent. The water levels in the UV channels are controlled by automatic level controllers. An UV module cleaning basin is provided. Design capacity of the UV system is 33 mgd Sludge Treatment and Storage Sludge is processed through an Autothermal Thermophilic Aerobic Digester (ATAD) package system. The ATAD system includes three ATAD reactors that can be operated in any combination. Normal operation will be in series from Reactor 1 through Reactor 3. The ATAD reactors provide a total of eight days detention at the design year 2015 solids loading. An aerated biosolids storage tank provides approximately seven months holding in the design year 2015 and approximately 9 months in the initial years of operation. A 15,000-gallon biosolids holding tank in the headworks holds sludge ready for disposal until removed by biosolids truck. It* t*j Facility Design Criteria The facility design criteria for the major treatment processes at the McMinnville Water Reclamation Facility are listed in Table 2-3. Item Design Conditions (Year 2015) Dry Weather Average Daily Flow Wet Weather Average Daily Flow Wot Weather Maximum Monthly Flow Wet Weather Maximum Daily Flow* Wet Weather Peak Flow Rate* Average BOD 5 Loading Average TSS Loading Average Ammonia-Nitrogen Loading Average Phosphorus Loading Table 2-3 Facility Design Criteria*" McMinnville Water Reclamation Facility 5.6 mgd 11.2 mgd 16,8 mgd 21.5 mgd 32.3 mgd 8,920 ppd 8,920 ppd 1,170 ppd 300 ppd Description Grit Removal Typo Number of units Diameter Hydraulic capacity Screening Type Number of units Capacity (each) Width Screen clear opening width Vortex concentrator 2 16 ft 32 mgd Mechanically cleaned bar screens 2 16 mgd 36 in 6 mm Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 2-6

41 Section 2.0 Wastewater Treatment Facilities Item Aeration Basins Type Number of units Total volume Sludge retention time Hydraulic retention time at design year average dry weather flow average wet weather flow MLSS Table 2-3 Facility Design Criteria* McMinnville Water Reclamation Facility Description Oxidation ditches 2 401,070 ft' 7 days 12.9 hrs 6,4 hrs 3,000 mg/l Secondary Clarifiers Number of units Diameter Overflow rate (design year) both units in service average dry weather flow average wet weather flow Tertiary Clarifiers Type Number of units Diameter Sidewater depth Recirculation rate Reactor detention time Upflow rate Filtration Filter type Number of units Loadings (design year) Disinfection Typo Number of channels Channel dimensions (ft) Number of lamps Total peak power consumption, kw WAS/Post Digestion Thickening Type Number or units Size Capacity, each Thickened sludge concentration ATAD Digesters Number of units Size, each diameter depth Total digestion detention time Design temperature Volatile solids loading Minimum volatile solids Volatile solids reduction ft 495 gpd/ft gpd/ft 2 Solids contact 2 70 ft 20 ft 13,750 gpm 30 min 0,6 gpm/ft z Monomedia gpm/ft 2 (average) Ultra-violet 3 UV channels 48x6x Gravity Belt Thickener meter 500 gpm 5-6% 3 35 ft 13 ft 8 days 60C 0.72 lbs/ft 1 54% 38% Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 2-7

42 Section 2.0 Wastewater Treatment Facilities I Table 2-3 Facility Design Criteria' 1 ' McMinnville Water Reclamation Facility (continued) Item Digested Biosolids Storage Type Number of units Size diameter depth Volume cubic feet gallons Solids concentration Detention time Sludge Utilization Load Solids content Flow Covered ft 20 ft 380,00 2,840,000 6% 210 days Description 7,920 Ibs/day 3.9% 24,000 gallons/day Notes; (1) Source: Contract Construction Documents, McMinnville Water Reclamation Facility, July INDUSTRIAL PREXREATMENT PROGRAM In accordance with Schedule E of NPDES Permit Number , the City of McMinnville is required to conduct and enforce an industrial pretreatment program that complies with all regulatory requirements established by DEQ and EPA. The McMinnville Water Reclamation Facility serves a population of approximately 28,000 persons with a current dry weather influent flow of approximately 2.88 mgd (2002 monitoring data). The allocation of flow for the City of McMinnville service area is as shown below: Flow Allocation: % Domestic % Commercial % Industrial = 83% = 10% = 7% There are currently no metal finishers or electroplaters discharging to the City of McMinnville sewerage systems. Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 2-8

43 Section 2.0 Wastewater Treatment Facilities Local Limits The City of McMinnville has established local limits for 11 pollutants of concern. The pollutants of concern and the maximum allowable headworks loading associated with each pollutant are presented in Table 2-4. Table 2-4 Local Limits for City of McMinnville Pollutants of Concern and Maximum Allowable Headworks Loadings Pollutant of Concern Arsenic Cadmium Copper Cyanide Lead Mercury Selenium Silver Zinc Maximum Allowable Headworks Loading (Ibs/day) 0,4157 0, , ,2265 0, ,0578 Local Limits' 1 ' (mg/l) 0, , , ,31 Notes: (1) Source! 1997 Local Limits Evaluation Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 2-9

44 Section 2.0 Wastewater Treatment Facilities Industrial Survey In accordance with Schedule E of NPDES Permit Number , the City of McMinnville conducts an annual industrial user survey for business and industries within the City of McMinnville service area. The existing SIUs in the City of McMinnville service area are listed in Table 2-5. Table 2-5 Significant Industrial Dischargers NAME OF INDUSTRY Amcrson Precision Sheet Metal S1U/CIU NDCIU CFR PART 433 PROCESS DISCHARGE NO NA1CS PERMIT ISSUED NO Cascade Rolling Mills NDCIU 420 D NO NO Fanner's Coop Creamery SIU 403 YES 3U5I4 YES Royal Pacific Industries, Inc. NDCIU 429G NO NO 2.4 SEPTAGE RECEIVING PROGRAM The McMinnville Water Reclamation Facility currently accepts septage from two active haulers (see Table 2-6). Both of the haulers are septic tank/holding tank pumpers, and one of the haulers (Chem- Cans) is a chemical toilet pumpers. Name Table 2-6 Approved Septage Haulers (as of July 1,2003) Address M. Hutchison Enterprises Chem-Cans PO Box 137 Newberg, OR PO Box 713 McMinnville, OR Septage Volumes The septic tank haulers discharge approximately 396,850 gallons per year and the chemical toilet pumpers discharge approximately 113,825 gallons per year. All septage haulers are pre-authorized to haul into the McMinnville Water Reclamation Facility and each load is certified and recorded, as to origin, address, amount (gallons) and characteristics. Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 2-10

45 Section 2.0 Wastewater Treatment Facilities Septage Dumping Requirements Septage dumping at the McMinnville Water Reclamation Facility is permitted in accordance with the following conditions: 1. Wastes shall consist of domestic wastes only from septic tanks, holding tanks or chemical toilets. 2. Wastes are to be delivered via a hauler who is licenses by Oregon DEQ. 3. Waste hauler must be pre-approved and authorized by the City of McMinnville Water Reclamation Facility prior to the delivery of septage waste. 4. Should problems arise within the plant, the City of McMinnville reserves the right to refuse any hauled wastes until such time as the plant is able to handle extra loadings. 5. Waste haulers will be held responsible if their dumped wastes cause upset, interference, or pass through at the Plant. Responsibility may include costs associated with cleanup and/or fines incurred. 6. Wastes must meet all applicable local, state and federal regulations. 7. Waste hauler may be required to have wastes tested, before dump, per any applicable local, state and federal regulations, 8. In addition to the existing log sheet, a separate form entitled "Waste Hauler Certification Report" must be completed with each load. The number on the upper right corner of this report is also to be entered into the company's monthly log sheet. Biosolids Management Plan Rev. 3.0 September 2003 City of McMinnville, Oregon Page 2-11

46 Section 3.0 Solids Treatment Processes 3.1 GENERAL Autothermal thermophilic aerobic digestion (ATAD) is the sludge stabilization process in operation at the McMinnville Water Reclamation Facility. This section of the Biosolids Management Plan describes the operation and regulatory compliance requirements associated with the solids treatment processes at the McMinnville Water Reclamation Facility. The site layout for the ATAD digesters at the McMinnville Water Reclamation Facility is presented in Figure 3-1, A picture of the digesters is shown in Graphic WASTE ACTIVATED SLUDGE Raw waste activated sludge will be pumped from the secondary clarifiers to gravity belt thickeners located in the headworks building, The gravity belt thickeners typically concentrate the sludgefrom0.8 percent to 5 percent total solids. After thickening, the thickened waste activated sludge is stored in a concrete wet well prior to being pumped to the first ATAD tank. The solids flow balance for raw sludge is presented in Table 3-1. Raw Sludge Type Return Activated Sludge Waste Activated Sludge Thickened Waste Activated Sludge Load (lbs/day) 241,000 10,500 10,100 Table 3-1 Raw Sludge Flow Balance (Design Year 201S) Total Solids (%) Notes; Source: Contract Construction Documents, McMinnville Water Reclamation Facility, July Flow (mgd) 3, ATAD OPERATION The McMinnville Water Reclamation Facility's ATAD system consists of three tanks, with one tank serving as a redundant unit. To operate the ATAD system, one day's volume (24,000 gallons during design year 2015) of digested biosolids will be pumped from the last ATAD tank in service to the aerated biosolids storage tank. Once this biosolids has been removed from the last ATAD tank, the ATAD tanks in service will be allowed to equalize by gravity, and then raw thickened waste activated sludge from the storage wet well will be pumped into the first ATAD tank. Raw sludge is pumped into the first tank in series and allowed to equalize between tanks until the proper operating capacity has been achieved. After achieving the correct operating level the isolation valves are closed and the system placed back into operation. This daily transfer should be done in a minimum amount of time; generally one half hour (0.5 hr) is required for the transfer, The design criteria for the ATAD process at the McMinnville Water Reclamation Facility are presented Table 3-3, Operational monitoring of the ATAD digestion system is through a Wonderware SCADA (Supervisory Control and Data Acquisition) control system, The detention time and temperature of the tanks is continuously recorded as depicted in Figure 3-2, An example of data collected through the SCADA system to determine digestion quality is shown in Table 3-2. Typical ATAD operation involves either two or three tank in-series operation. Current (2003) solids loading rates into the McMinnville Water Reclamation Facility require typical waste sludge rates of approximately 15,000 gallons per day of five percent (5 percent) total solids. With two reactors in Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 3-1

47 Section 3.0 Solids Treatment Processes operation (total capacity of 134,000 gallons), this would result in a detention time of slightly more than 8.9 days. If three reactors are in operation (201,000 gallons), the typical detention time would be approximately 13.4 days. The design minimum detention time is 5 days at 55 degrees Celsius. Figure 3-1 ATAD SITE LAYOUT Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 3-2

48 Section 3,0 Solids Treatment Processes Figure 3-2 ATAD Monitoring System 1 *. JiifrairJi WimfawVli-Wtf* fl \WfSF 'te i*».?krfj 1 JF*K* 6/16(35 \:ti.4f HISTORICAL TRENDING!)vrkfyv v, n^liit Scrrf ri j ScnT.-k <t~*ri. lultll.s <& City Ovcvew W.l nwrvltw Uvrrflcwii'i'n I CuiicilAlJmi. J CispUy M; I'uip S'»i or. tlt'm I A'trnVEvci I t-'j'ary J H i(-.i!c«l Tf Trendo U«fy (utile * Ihid figure shows a two-tank sequence in operation for three (3) days, The severe changes in temperature are due to the daily batch transfer of undigested sludge into the first reactor and the transfer of treated biosolids out of the second reactor. The first reactor is operating in the mid-fifty (50) degrees Celsius range and the second reactor is operating in the mid sixty (60) degrees Celsius range, Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 3-3

49 Section 3.0 Solids Treatment Processes Time 0:04:19 1:04:19 2:04:19 3:04:19 4:04:19 5:04:19 6:04:19 7:04:19 8:04:19 9:04:19 10:04:19 11:04:19 12:04:19 13:04:19 14:04:19 15:04:19 16:04:19 17:04:19 18:04:19 19:04:19 20:04:19 21:04:19 22:04:19 23:04:19 Table 3-2 Example Time /Temperature Monitoring Data Reactor #1 (C ) 37, , ,68 37, August 27, 1999 Reactor #2 (C) ,28 57, , ,24 58, ,12 59, , ,24 Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 3-4

50 Section 3.0 Solids Treatment Processes Graphic 3-1 ATAD Digesters Biosolids Management Plan Rev, 3.0 City of McMinnville, Oregon September 2003 Page 3-5

51 Section 3,0 Solids Treatment Processes Sludge withdrawal, transfer and filling are performed as batch operations that require approximately one hour each day to complete. During the sludge withdrawal, transfer and filling operation the aeration system for each tank will be de-energized; otherwise, the sludge is under aeration the remaining 23 hours each day. Table 3-3 ATAD Digester Design Criteria ATAD Digesters Number of units Size, each Diameter Depth Volume Total digestion detention time Design temperature Volatile solids loading Minimum volatile solids Volatile solids reduction 3 35 ft 13 ft 67,000 gal 8 days 60 C 0.72 lbs/tf 54% 38% 3.4 ATAD REGULATORY COMPLIANCE The City of McMinnville biosolids management program complies with all applicable state and federal regulations. The applicable federal regulations are 40 CFR, Part 503, Standards for the Use and Disposal of Sewage Sludge, and the applicable state regulations are Oregon Administrative Rule 340, Division 50, "Land Application of Domestic Wastewater Treatment Facility Biosolids, Biosolids Derived Products, and Domestic Septage." Biosolids must meet pollutant limits, pathogen requirements, and vector attraction reduction requirements in order to be suitable for land application. This section discusses Class A biosolids that are applied in bulk to agricultural land, forestland and reclamation sites Pathogen Requirements In the past, EPA designated sludge-stabilization technologies as either (1) a process to significantly reduce pathogens (PSRP) or (2) a process to further reduce pathogens (PFRP), The PFRP technologies produce a sludge product with a lower pathogen content and reduced risk for disease transmission than PSRP systems. With promulgation of the Part 503 regulations, EPA decided to phase out the PSRP and PFRP designations and utilize new designations -- Class A and Class B. Class A biosolids meets the previous PFRP requirements, while Class B complies with the former PSRP criteria. The pathogen content must meet Class A criteria to apply biosolids product to lawns, gardens, and other high public exposure areas such as parks, golf courses, soccer fields, etc. Biosolids need only meet the Class B designation for controlled application to agricultural and nonagricultural sites where access to the public is restricted. Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 3-6

52 Section 3,0 Solids Treatment Processes Prior to the promulgation of 40 CFR Part 503, the PFRP definition for the ATAD process was as presented below: "Liquid sludge is agitated with air or oxygen to maintain aerobic conditions at residence times of 10 days at 55 C to 60 C, with a volatile solids reduction of at least 38 percent." With the promulgation of the new 40 CFR Part 503 regulations, EPA has established the Class A requirements for ATAD as follows: Either Or A fecal coliform density less than 1,000 most probable number (MPN) per gram of total solids. A Salmonella sp. density of less than 3 MPN per 4 grams of total solids. Pathogen Reduction Requirements are met under 40 CFR (a)(3) Alternative 1 by Autothermal Thermophilic Aerobic Digestion (ATAD). Monitoring requirements of (a)(3)(i); biosolids containing <1000 MPN Fecal Coliform/gram total solids (dry weight) and time/temperature requirements in (a)(3)(ii)(D); when sewage sludge solids concentrations are <7 percent (Equation 3), SRT = ,14t Where "t" = Temperature in degrees Celsius The ATAD process typically generates a temperature between 50 C and 60 C, Table 3-4 outlines the temperatures and corresponding solids retention time (SRT) that are required per the above equation. Table 3-4 Time and Temperature Guidelines Temperature (C) SRT (days) 5,0 3, Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 3-7

53 Section 3,0 Solids Treatment Processes Vector Attraction Reduction Requirements In addition to meeting the Class A pathogen criteria, McMinnville biosolids also meet the vector attraction reduction criteria, Regulations for the beneficial use of biosolids allow land application if the following vector attraction reduction requirement is met: All ATAD stabilized biosolids stored in the aerated biosolids storage tank will meet the 38 percent volatile suspended solids (VSS) destruction requirements (40 CFR b,l). See Section 6.3 for a sample calculation of VSS destruction. If the biosolids does not meet the 38 percent requirement above, the biosolids in the storage tank must meet: laboratory bench test of less than 15 percent additional VSS destruction ( b.3) or laboratory test for specific oxygen uptake rate of 1.5 mg or less oxygen per hour per gram (40 CFR b.4). 3.S HISTORIC TRACE POLLUTANT CONCENTRATIONS Table Biosolids Trace Pollutant Loadings (mg/kg) CUy of McMinnville Water Reclamation Facility Pollutant of Concern Maximum Minimum Exceptional Quality Standard Arsenic Cadmium 7, Copper ,500 Lead Mercury Molybdenum Nickel Selenium 7.6 3,6 100 Zinc ,800 Notes: Source: City of McMinnville Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 3-8

54 Section 3.0 Solids Treatment Processes 3.5,1 Typical Biosolid Characteristics Table 3-6 Parameter Units Biosolids Analysis Data 3/6/2002 6/5/2002 9/22/ /4/2002 Average Arsenic Cadmium Copper Lead Mercury Molybdenum Nickel Selenium Zinc Silver Chromium Cyanide Total Keldahl Nitrogen Ammonia Nitrogen Nitrate Nitrogen Total Phosphorus Potassium Total Solids Volatile Solids % Volatile Reduction Fecal Coliform ph mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg %dry wt. %drywt. %dry wt. %dry wt. %drywt. % % % /gm SU 13,2 1, i < , ,54 2,5 1, ,1 7, ,8 3,2 6,7 24, ,0 28,0 <0,0I <,0060 5,44 2, ,2 8, ,0 1,4 9, , < , , ,0 30, <4,60 13, <,0077 4, , ,0 1, <,0063 4, ,9 8,1 Biosolids Management Plan Rev, 3.0 City of McMinnville, Oregon September 2003 Page 3-9

55 Section 4.0 Biosolids Storage 4.1 BIOSOLIDS STORAGE During the pre-design phase for the McMinnville Water Reclamation Facility, DEQ recommended that aeration be added to the sludge storage tank to provide additional VSS destruction capabilities to the ATAD process. Sludge stabilization using the ATAD tanks will reduce the total solids concentration from 6 percent to approximately percent. The aerated biosolids storage tank is aerated by diffused air, and has a storage capacity of 2,830,000 gallons. This storage volume will provide approximately 120 days of biosolids (at 2.5 percent total solids) storage in the design year The design criteria for the aerated biosolids storage tank are presented in Table 4-1. Table 4-1 Aerated Biosolids Storage Tank Design Criteria Aerated Biosolids Storage Tank Type Number of units Size Diameter Depth Volume Cubic feet Gallons Solids concentration Detention time Covered ft 20 ft 380,00 2,840,000 6% 210 days A feature of the McMinnville Water Reclamation Facility is the capability for biosolids to be pumped from the aerated biosolids storage tank to the gravity belt thickeners in the headworks building for post stabilization (re-cuperative) thickening. In this manner, the City can increase the solids concentration of stabilized biosolids from 2.5 percent totals solids to 6 percent total solids ~ thereby reducing the volume of the biosolids and increasing onsite storage time to approximately 210 days. An additional operational feature added after plant start-up is the capability to return supernate from the upper areas of the storage tank to the secondary process. This capability significantly increases storage time and enhances thickening within the tank. Biosolids concentrations of >15 percent total solids have been achieved by this method, Odors from the ATAD digestion process are removed from the vessels and prescrubbed of high ammonia concentrations through a water mist scrubber, The remaining odorous air is then pumped through a Biofilter for final scrubbing and decomposition of odors. The Biofilter at the facility has proven to be extremely effective at stabilizing odors from the ATAD digestion process. During the dry season, stabilized biosolids will be pumped from the aerated biosolids storage tank to an elevated biosolids truck loading tank. The aerated biosolids storage tank will be emptied each dry season, so emergency storage capacity will be available. Graphic 4-1 depicts both the Biosolids Storage Tank and Biofilter. Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 4-1

56 Section 4,0 Biosolids Storage Graphic 4-1 Biosolids Storage Tank and Biofilter Biosolids Management Plan Rev, 3,0 City of McMinnville, Oregon September 2003 Page 4-2

57 Section 5.0 Contingency Options 5.1 BACKGROUND In November 1992, DEQ expressed concerns regarding the implementation of ATAD technology for sludge stabilization at the McMinnville Water Reclamation Facility. DEQ indicated that their concerns regarding the technology were due to; (1) the limited information available on technology performance; (2) the fact that some data showed inconsistent performance that would not have been in compliance with 40 CFR 503 requirements had the installation been operated in the U.S.; and (3) the absence of EPA certification for the process. For these reasons, DEQ requested the City of McMinnville to include the construction of a "back up process" at the McMinnville Water Reclamation Facility to guarantee that the City's final biosolids product would be in compliance with all requirements for the land application of biosolids. In September 1993, DEQ changed their position regarding ATAD technology, and concurred with the City that the biosolids produced by the ATAD system at the McMinnville Water Reclamation Facility should be in full compliance with all requirements for the land application of biosolids. Accordingly, DEQ relieved the City from having to implement a "back up process" as part of the initial construction of the McMinnville Water Reclamation Facility. Instead, DEQ allowed the City the opportunity to submit an "Implementation Plan for Emergency Lime Stabilization of Sludge" as a means of underwriting the ATAD process and guaranteeing that the biosolids produced from the new ATAD system will be in full compliance with 40 CFR EMERGENCY LIME STABILIZATION Lime stabilization of sludge can meet vector attraction reduction requirements under b.6 and the Class B Alternative 2 under (b)(3) for pathogen reduction requirements. A lime feed and blending package unit can be easily installed on top of the sludge loading holding tank, The sludge loading pipe would be extended up to the package unit, and bagged lime would be brought up to the unit by the headworks building elevator. If lime stabilization became a permanent process, a lime silo would be added to eliminate bag handling. The liquid capacity of the biosolids loading tank is 15,000 gallons. This will allow the sludge in the tank to maintain the high ph required for 24 hours prior to land application, The budget cost of the lime stabilization unit is $60,000 and the delivery time is 10 to 12 weeks. Given that the City of McMinnville has 210 days (at design year 2015 conditions) of biosolids storage capacity in the aerated biosolids storage tank, it is apparent that the City has sufficient time to implement a lime stabilization unit if it is warranted. Biosolids Management Plan Rev. 3.0 September 2003 City of McMinnville, Oregon Page 5-1

58 Section 6.0 Biosolids Sampling Program 6.1 MONITORING FREQUENCIES The City of McMinnville's biosolids management program will be required to monitor the quality of its biosolids production in accordance with the following three regulatory requirements: NPDES Permit No , 40 CFR , and OAR 340, Division 50, subsection SAMPLING PROGRAM Biosolids analyses will be performed on representative samples in accordance with the sampling schedule and methodologies detailed in Table 6-1. The monitoring frequencies for the three regulatory requirements are also listed in Table 6-1. A resource for sampling methods is; EPA Publication, "Test Methods for Evaluating Solid Waste, Volume 2" ; Field Manual, Physical/Chemical Methods, November 1986, Third Edition, Chapter 9. All analytical testing procedures will be performed in accordance with the following sampling and analytical methods: 40 CFR Part 503.8; EPA Publication, "POTW Sludge Sampling and Analysis Guidance Document", 1989; EPA Publication, "Control ofpathogens and Vector Attraction in Sewage Sludge", 1992; and EPA Publication, "POTW Sludge Sampling Procedures and Protocols for the National Sewage Sludge Survey", CALCULATION FOR VOLATILE SOLIDS REDUCTION The solids digestion process and storage tank combination make calculation of volatile solids reduction to achieve vector attraction reduction requirements difficult. The use of seasonal supernating from the storage tank and seasonal withdraws from the tank would make mass reduction determinations very difficult to calculate. Due to the difficulties in obtaining accurate inputs for the volatile solids reduction calculation, the primary method used to ensure that vector attraction reduction requirements have been achieved is the calculation of the volatile solids mass reduction achieved through the ATAD digesters. This calculation is reported on a quarterly basis from Equation 6-2. Additional volatile solid mass reduction is achieved during the long-term storage in the Biosolids Storage Tank, which further stabilizes the digested solids beyond that calculated as described above. The volatile solids reduction for the City of McMinnville's biosolids management program will be calculated by performing volatile solids calculation on the thickened waste activated sludge being fed into the ATAD system and the digested biosolids withdrawn from the last ATAD in operation. The volume of digester influent flow and ATAD digester effluent flow is also included in the calculation to account for the evaporation of water and gases from the ATAD system operated at high temperatures. Sample data is shown in Table 6-2 and demonstrated in Equation 6-2. Biosolids Management Plan Rev. 3.0 September 2003 City of McMinnville, Oregon Page 6-1

59 Section 6.0 Biosolids Sampling Program In addition to the quarterly sampling described above, monthly sampling will be performed on the biosolids being hauled during the period of biosolids land application. Seven grab samples from separate truckloads will be composited and volatile solids reduction calculated comparing to the thickened waste activated sludge being fed into the ATAD system according to Equation 6-3, Sample data is presented in Table 6-3 for this example calculation, Biosolids Management Plan Rev, 3,0 September 2003 City of McMinnville, Oregon Page 6-2

60 Section 6.0 Biosolids Sampling Program Table 6-1 Biosolids Monitoring Program Sample Sample Location / Frequency Parameter Type Raw Sludge Analyses Total Solids, Composite TWAS wet well' 2 ' Monthly' 6 ' /Quarterly (% dry weight) Volatile Solids Composite TWAS wet well' 2 ' Monthly"" /Quarterly (% dry weight) Stabilized Sludge (Biosolids) Analyses Total Solids, (% dry weight) Volatile Solids (% dry weight) Fecals NH 3 -N (% dry weight) NOj-N (% dry weight) TKN (% dry weight) Phosphorous (% dw) Potassium (% dw) Ag (mg/kg dw) As (mg/kg dw) Cd (mg/kg dw) Cr (mg/kg dw) Cu (mg/kg dw) CN (mg/kg dw) Pb (mg/kg dw) Hg (mg/kg dw) Mo (mg/kg dw) Ni (mg/kg dw) Se (mg/kg dw) Zn (mg/kg dw) ph (standard units) Composite Composite Grab (1) Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite Composite ATAD Process Monitoring Detention time (days) N/A Temperature Plant Control (degree C) System ATAD' 4 '/Quarterly ATAD' 4 ' /Quarterly ATAD'"/Quarterly ATAD' 4 '/Quarterly ATAD /Quarterly ATAD <4) /Quarterly ATAD!4) /Quarterly ATAD (4) /Quarterly AT AD (4) /Quarterly ATAD'*' /Quarterly ATAD' 4 ' /Quarterly ATAD' 4 '/Quarterly ATAD (4) /Quarterly ATAD (4) /Quarterly ATAD' 4 '/Quarterly ATAD«/Qiiarterly ATAD' 4 ' /Quarterly ATAD (4) /Quarterly ATAD 14 ' /Quarterly ATAD' 4 '/Quarterly ATAD 00 /Quarterly ATADs in operation ATAD Truck' 5 '/Monthly' 6 ' Truck' 5 '/Monthly' 6 ' Truck /Monthly' 6 ' Truck' 5 '/Monthly' 6 ' Truck' 5 '/Monthly' 6 ' Truck'"/Monthly' 6 ' Truck' 5 '/Monthly"" Truck' 5 '/Monthly"" Truck' 5 '/Monthly Truck' 5 '/Monthly' 6 ' Truck' 3 '/Monthly' 6 ' Truck' 5 '/Monthly* Truck' 5 '/Monthly"" Truck' 5 '/Monthly' 6 ' Truck (5 '/Monthly' 6 ' Truck' 5 '/Monthly' 6 ' Truck' 5 '/Monthly' 6 ' Truck' 5 '/Monthly"" Track' 5 ' /Monthly' 6 ' Truck' 5 ' /Monthly' 6 ' Quarterly Quarterly"' Exceptional Quality Standard 1,000 MPN/gram 41 mg/kg 39 mg/kg 1,200 mg/kg 1,500 mg/kg 300 mg/kg 17 mg/kg 75 mg/kg 420 mg/kg 100 mg/kg 2,800 mg/kg 5 days 50 C Notes: (1) This is a grab sample collected from the final ATAD Effluent, (2) This is a composite sample comprised of aliquots of equal volume collected daily, consecutively over seven (7) day period and then combined from the Thickened Sludge Wet Well. (3) Temperature shall be detennined by calculating the average of seven independent temperature readings collected over seven consecutive days. (4) This is a composite sample comprised of equal aliquats of seven grab samples from the final ATAD effluent taken consecutively over a seven (7) day period and composited, (5) This is a composite sample comprised of equal aliquats of seven grab samples from different truckloads of biosolids to bo landapplied, (6) Monthly during periods of biosolids land application. Biosolids Management Plan Rev. 3.0 City of McMinnville, Oregon September 2003 Page 6-3

61 Section 6.0 Biosolids Sampling Program Table 6-2 Sample Calculation Volatile Solids Mass Reduction (through ATAD system) Raw Sludge (Thickened Waste Sludge Wet Well / Digester Influent) Biosolids (ATAD Digester Effluent)'" Sample Date Total Solids (% diy wt) Volatile Solids Fraction (%) Volatile Solids (% dry wt) Sample Date Total Solids (%drywt) Volatile Solids Fraction (%) Volatile Solids (%drywt) 3/4/2003-3/10/ , /12/2003 & 3/26/2003 Notes: (7) This is a composite sample comprised of aliquots of equal volume collected daily, consecutively over seven (7) day period and then combined from the Thickened Sludge Wet Well. (8) This is a composite sample comprised of aliquots of equal volume collected daily, consecutively over seven (7) day period ' and then combined from the final ATAD Effluent, Jan-Mar 2003 Average Daily Digester Influent Flow = gal; Jan-Mar 2003 Average Daily Digester Effluent Flow = gal Equation 6-2 for Calculating Volatile Solids Mass Reduction (through ATAD system): VSMR ffvsg^* DOm) - (VSgg * DCW» * 100 Where, VSMR = Volatile solids mass reduction, % VSRS = Volatile solids content of raw sludge (Digester Influent) (% dry weight) VS S s = Volatile solids content of stabilized sludge (Digester Effluent) (% dry weight) DQFN = Digester Influent Flow (gallons) DQEFF = Digester Effluent Flow (gallons) For the example data presented in Table 6-2: VSMR = ((3.10*18751)-(1.61*17884))* 100 (3.10*18751) or (58,128-28,7931*100 58,128 VSMR = 50.5 % Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 6-4

62 Section 6.0 Biosolids Sampling Program Table 6-3 Sample Calculation Volatile Solids Mass Reduction (to biosolids application trucks) Raw Sludge (Thickened Waste Sludge Wet Well / Digester Influent) <9) Biosolids (Truckloads)" 0 ' Sample Date Total Solids (% diy wt) Volatile Solids Fraction (%) Volatile Solids (% dry wt) Sample Date Total Solids (% dry wt) Volatile Solids Fraction (%) Volatile Solids (% dry wt) 3/4/2003-3/10/ ,1 3,10 7/12/2003 & 7/20/2003 Notes: (9) This is a composite sample comprised of aliquots of equal volume collected daily, consecutively over seven (7) day period and then combined from the Thickened Sludge Wet Well. (10) This is a composite sample comprised of equal aliquats of seven grab samples from different truckloads of biosolids to be land applied and composited Equation 6-3 for Calculating Volatile Solids Reduction (through Biosolids land application): VSR = (VS P g- VS»g) * 100 vs RS Where, VSR = Volatile solids reduction, % VS RS = Volatile solids content of raw sludge (Digester Influent) (% dry weight) VSBS = Volatile solids content of biosolids (loaded into tracks) (% dry weight) For the example data presented in Table 6-3: VSMR (3,10-1,0)* or (2.11* VSMR 67.7 % Biosolids Management Plan Rev. 3,0 City of McMinnville, Oregon September 2003 Page 6-5

63 Section 7.0 Reporting and Record Keeping Requirements 7.1 REPORTING REQUIREMENTS The City of McMinnville's biosolids management program will produce "exceptional quality" biosolids in bulk form for application to land. The City will be required to submit annual reports to DEQ and EPA pertaining to biosolids quality and quantity and land application activities. The requirements for each annual report are discussed in the following sections. 7.2 RECORD KEEPING REQUIREMENTS Any biosolids produced not meeting Class A requirements, but meeting Class B standards will be applied to DEQ approved sites. The Class B biosolids, if any, will require record keeping on all sites having biosolids applied DEQ Reporting and Record Keeping Requirements DEQ's reporting and record keeping requirements for biosolids management programs are defined in OAR 340, Division 50, subsection 035. The annual report is due to DEQ, on or before, February 19 of each year. The requirements of the report are as listed below. The City is required to retain this information in accordance with 40 CFR Part (fiveyears), (1) Copies or summaries of all biosolids testing performed. (2) Information sufficient to demonstrate that solids met pathogen reduction requirements required under 40 CFR Part , and vector attraction reduction requirements required under 40 CFR Part EPA Reporting and Record Keeping Requirements EPA's reporting and record keeping requirements for biosolids management programs are defined in 40 CFR Part 503,18 and Part , respectively. The annual report is due to EPA, on or before, February 19 of each year. The requirements of the report are as listed below. The City is required to retain this information in accordance with 40 CFR Part (fiveyears). The concentration of each regulated pollutant listed in Table 3 or 40 CFR Part A signed certification stating that all applicable requirements of the regulations have been met. A description of how the pathogen requirements are met. A description of how the vector attraction reduction requirement is met. Biosolids Management Plan Rev September 2003 City of McMinnville, Oregon Page 7-1

64 Section 8.0 Biosolids Utilization Program 8.1 PROGRAM OVERVIEW Biosolids applied to agricultural lands are predominantly used for small grain and grass seed production. There is a portion of McMinnville's biosolids that are applied to pasture land. The City of McMinnville will land apply biosolids predominantly during the dry season -- weather permitting and based on market demand. During the wet weather season and inclimate weather, biosolids will be stored onsite at the McMinnville Water Reclamation Facility in the aerated biosolids storage tank, which has a total of 120 days of biosolids (2.5 percent dry solids) storage capacity. Biosolids will be applied to agricultural lands as a liquid with a total solids content of approximately percent total solids. The biosolids application will be conducted with a private hauling company under contract. Typical application equipment is semi-tractors equipped with pressurized 6,000 to 7,000 gallon tanks. When trucks are to be driven directly onto the fields, the biosolids are applied in overlapping swaths. Biosolids application equipment and labor are typically provided by the contract hauler. However, the City organizes the application fields and coordinates the application between the landowner and hauler. 8.2 AGRONOMIC LOADING RATES Biosolids application rates are formulated from crop nutrient requirements established by Oregon State University Extension Service, Consultations with the farmers determine what methods seem to produce the best results and all attempts are made to establish the maximum benefit to the farmer with the established regulations and guidelines for the land application of biosolids, 8.3 LAND APPLICATION EQUIPMENT Supplied by the contract hauler. Graphic 8-1 depicts a typical biosolids application with contract equipment applying the product in a beneficial land application project. Biosolids Management Plan Rev September 2003 City of McMinnville, Oregon Page 8-1

65 Section 8.0 Biosolids Utilization Program Graphic 8-1 Land Application Project Biosolids Management Plan Rev. 2,11 City of McMinnville, Oregon September 2003 Page 8-2

66 Section 8.0 Biosolids Utilization Program 8.4 LAND APPLICATION SITE INVENTORY City of McMinnville Land Application Site Inventory (as of 3/10/95) Field # Owner Name Legal Description Gross Acres Net Acres Approval Date Approval Period 105A City of McMinnville T4S-R4W-SI /24/95 1/1-12/31 105B City of McMinnville T4S-R4W-S /24/95 1/1-12/31 1I0A Aebi, Wallace T4S-R4W-S /23/85 1/1-12/31 HOB Aebi, Wallace T4S-R4W-S /23/85 1/1-12/31 HOC Aebi, Wallace T4S-R4W-S /23/85 5/15-10/15 HOD Aebi, Wallace T4S-R4W-S3& /23/85 5/15-10/15 HOE Aebi, Wallace T4S-R4W-S /23/85 I/1-I2/31 110F Aebi, Wallace T4S-R4W-S /23/85 1/1-12/31 n oo Aebi, Wallace T4S-R4W-S /23/85 5/15-10/ Aebi, Wallace T4S-R4W-S /23/85 1/1-12/ Airport, City MCM T4S-R4W-S /12/93 6/1-10/ Bernards, Mike T4S-R5W-S /23/85 4/15-10/15 250A Boyer, William T4S-R4W-S /02/83 4/15-10/15 2S0B Boyer, William T4S-R4W-S /02/83 1/1-12/31 " 250C. Boyer, William T4S-R4W-S /02/83 4/15-10/15 250D Boyer, William T4S-R4W-S /02/83 1/1-12/31 250E Boyer, William T4S-R4W-S /02/83 1/1-12/31 250F Boyer, William T4S-R4W-S /02/83 4/15-11/ Hanger, Helen T4S-R4W-S /23/8S 4/15-10/15 500A Haworth, Vincent T4S-R4W-S /04/76 4/15-10/15 500B Haworth, Vincent T4S-R4W-S /04/76 4/15-10/15 550A Herron, Larry T6S-R5W-S /25/93 6/1-9/30 550B Hcrron, Laity T6S-R5W-S /25/93 6/1-9/30 570A Hurner, Carl T3S-R4W-S /24/95 1/1-12/31 570B Hurner, Car! T3S-R4W-S /24/95 1/1-12/31 570C Hurner, Carl T3S-R4W-S /24/95 1/1-12/31 570D Hurner, Carl T3S-R4W-S /24/95 1/1-12/31 570E Hurner, Carl T3S-R4W-S /24/95 1/1-12/31 Biosolids Management Plan Rev City of McMinnville, Oregon September 2003 Page 8-3

67 Section 8.0 Biosolids Utilization Program City of McMinnville Land Application Site Inventory (as of 3/10/95) Field # Owner Name Legal Description Gross Acres Net Acres Approval Date Approval Period 570F Humor, Carl T3S-R4W-S /24/95 1/1-12/31 570G Hurner, Carl T3S-R4W-S /24/95 1/1-12/31 570H Hurner, Carl T3S-R4W-S /24/95 1/1-12/31 6I0A Johnson, Robert T4S-R4W-S2& /05/91 1/1-12/31 610B Johnson, Gary T4S-R4W-S /05/91 1/1-12/31 720A Morgan, Wilbur T4SR-R4W-S /24/95 1/1-12/31 750A Pekkola, Larry T3S-R4W-S /06/92 1/1-12/31 750B Pekkola, Larry T3S-R4W-S / /1-12/31 750C Pekkola, Larry T3S-R4W-S /06/92 1/1-12/31 750D Pekkola, Larry T3S-R4W-S /06/92 1/1-12/31 750B Pekkola, Larry T3S-R4W-S /06/92 1/1-12/31 750F Pekkola, Larry T3S-R4W-S /06/92 1/1-12/31 751A Pekkola, Larry Jr. T3S-R4W-S /06/92 1/1-12/31 751B Pekkola, Larry Jr. T3S-R4W-S /06/92 5/1-10/30 760A Peterson, Alfred T3S-R4W-S /24/95 1/1-12/31 760B Peterson, Alfred T3S-R4W-S /24/95 1/1-12/31 840A Sheldon, Clint T3S-R4W-S /24/95 1/1-12/ Strahm, Ernie T3S-R5W-S /12/93 1/1-12/31 Total Acres LAND APPLICATION MANAGEMENT PRACTICES The State of Oregon, the Environmental Protection Agency, and the City of McMinnville recognize exceptional quality biosolids as a safe, marketable commodity, with characteristics and attributes similar to readily available commercial fertilizers. As such, there will be no time-required restricted access periods where exceptional quality biosolids are land applied. Biosolids Management Plan Rev. 2,11 City of McMinnville, Oregon September 2003 Page 8-4

68 Section 8.0 Biosolids Utilization Program 8.6 PUBLIC NOTIFICATION The City of McMinnville is not required to provide public notification to landowners and occupants adjacent to or abutting land application sites. Public notification for any Class B biosolids application projects will be conducted in accordance with applicable OAR 340, Division 50 rules. 8.7 SITE SELECTION CRITERIA The following site selection criteria would apply only when the City of McMinnville is applying Class B biosolids. Site approval must be consistent with local land use plans. The following site conditions when determining the suitability of a site for land application: Stability of the geologic formation of the site and the possibility of flooding, Minimum depth to permanent groundwater should be four feet, Topography of the site shall not exceed a slope of 12 percent for liquid application of biosolids. Minimum soil rooting depth of 24 inches. Proximity to residential areas shall include an appropriate buffer strip with the size depended upon the type of application. No application of biosolids will occur within 50 feet to any ditch, channel, pond or waterway or within 200 feet of a domestic water source or well. Proximity to well-traveled highways and waterways shall include an appropriate buffer strip for the application. These and other site selection considerations are outlined in DEQ's biosolids management rales (OAR 340 Division 50), which are provided in Appendix F. An adequate land base is available for current and future operations. Less than 300 acres of the DEQ approved 2,321 acres are used each year to meet the current program needs. Future sites would in the general vicinity of the existing site locations and may included locations in Polk County and would be approved based on the requirements of Division 50. Biosolids Management Plan Rev September 2003 City of McMinnville, Oregon Page 8-5

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70 Appendix B: Antidegradation Review Sheet Attachment 4 ANTIDEGRADATION REVIEW SHEET FOR A PROPOSED INDIVIDUAL NPDES DISCHARGE 1. What is the name of Surface Water that receives the discharge? Briefly describe the proposed activity: Is this review for a Go to Step 2. renewal OR new (circle one) permit application? 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 Is this surface water a High Quality Water? Yes, Go to Step 8. No. Go to Step 4. Hf 4. Is this surface water a Water Quality Limited Water? Yes. Go to Step 13. Yes No. Go to Step 2. Note; The surface water must fall into one of three (3) categories: Outstanding Resource Water (Step 2), High Quality Water (Step 3), or Water Quality Limited Water (Step 4). 13. Will the proposed activity result in a Lowering of Water Quality in the Water Quality Limited Water? Yes. Go to Step 14. No. Proceed with Permit Application. Applicant should provide basis for conclusion. Go to Step 24.

71 24. On the basis of the Antidegradation Review, the following is recommended: _XX_ Proceed with Application to Interagency Coordination and Public Comment Phase. Deny Application; return to applicant and provide public notice. Action Approved Section; Review Prepared By: Phone: Date Prepared: Mark E, Hamlin (503) , ext. 239_ December 11,2003 Please provide the following information and submit with the completed application form to: Department of Environmental Quality Water Quality Division Surface Water Management 811 SW Sixth Avenue Portland, Oregon Name:.Name of Company; Address: Phone: Fax:

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73 Wastewater System Classification Worksheet for Operator Certification OAR General Requirements (OAR ) - Each owner of a regulated wastewater system must have its system supervised by one or more operators who hold a valid certificate for the type of system, wastewater treatment or collection, and at a grade equal to or greater than the wastewater system classification as defined in OAR and 0025, DEQ will advise system owners of the classification of their systems as a permit action. As the classification establishes the operator certificate type and grade required for compliance, it needs to be set prior to "start-up" of a new or upgraded and/or expanded facility. Wastewater treatment system classifications will be derived from the total points assigned based on criteria shown in OAR (see Classification Worksheet). Collection system classifications are based on design population or population equivalent to be served by a wastewater treatment system (see Worksheet). Upon written notice to the wastewater system owner, DEQ may classify a wastewater treatment system higher than the classification based on accumulated points if the complexity of a treatment system is not reflected in the critena(see Worksheet examples). If deemed appropnate, DEQ may classify a wastewater collection system higher than the classification based on population when a Class I by population will have significant pumping of sewage including STEP or other pumping that may warrant a Class II designation. In either case, designation must be consistent with the intent of the classification system (see OAR (4} & (5)). Classification of Wastewater Systems (OAR ) All wastewater systems regulated under OAR will be classified by DEQ as wastewater treatment systems and/or wastewater collection systems, as appropriate, in accordance with the following classification system; Wastewater Treatment Systems Class I - 30 total points or less Class II total points Class III total points Class IV - 76 or more points Wastewater Collection Systems Class I -1,500 or less design population Class II -1,501 to 15,000 design population Class III -15,001 to 50,000 design population Class IV - 50,001 or more design population Definitions used in these regulations unless otherwise required by context (see OAR ): "Average Dry Weather Flow" (ADWF) means the design average dry weather flow capacity of the wastewater treatment system in gallons per day or Million Gallons per Day (MGD), as approved by the Department, "Industrial Waste" means liquid wastes from an industrial or commercial process discharged into a wastewater system for conveyance and treatment. "NPDES Permit" means a waste discharge permit issued in accordance with requirements and procedures of the National Pollutant Discharge Elimination System authorized by Section 402 of the Federal Clean Water Act and OAR 340, Division 45. "Population" means the design population of the wastewater system represented as the number of people or the population equivalent the system is designed to serve. Equivalent population ordinarily is determined based on 70 gallons per person per day average dry weather flow (ADWF) or 0,17 lbs. BODS per person per day, whichever is greater. "Wastewater" or "sewage" means the water-carried human or animal waste from residences, buildings, industrial establishments or other places, together with such groundwater infiltration and surface water as may be present. The admixture of domestic and industrial waste or other by-products, such as sludge, is also considered wastewater or sewage. "Wastewater Treatment System" or "Sewage Treatment System" means any structure, equipment or process for treating and disposing of, or recycling or reusing wastewater and sludge (including industrial waste) that Is discharged to the wastewater system. "Wastewater Collection System" or "Sewage Collection System" means the trunks, arterials, pumps, pump/lift stations, piping and other appurtenances necessary to collect and carry away wastewater or other liquid waste treatable in a community or private wastewater treatment facility. "Wastewater System" means "Sewage Treatment Works" defined in ORS 448,405 as any structure, equipment or process required to collect, carry away and treat domestic waste and dispose of sewage as defined in ORS Typically, components of a wastewater system include a wastewater collection system and a wastewater treatment system. "WPCF Permit" means a Water Pollution Control Facilities permit to construct and operate a collection, treatment and/or disposal system with no discharge to navigable waters.

74 Wastewater System Classification Worksheet for Operator Certification OAR WW System Common Name: City of McMinnville Water Reclamation Facility Facility ID: Location: 3500 Clearwater, McMinnville, OR Total Points (from page 3): 117 WWT Class (check): Dl» HI M IV Design Population 1 : 80,000 WWC Class (check): Dl II Dm Kl IV Design ADWF load (Influent MGD) 5J3 Design BOD load (Influent lbs./day) 8920 Classified bv: Mark E. Hamlin Date: December Date this classification filed with the Operator Certification office: System start-up date for this classification (new, upgrade or expansion): Is this a change from a prior classification? (check): Yes lelno Criteria for Classifying Wastewater Treatment Systems (OAR ) (1) Design Population or Population Equivalent Points (10 Points Maximum) Less than points 751 to point 2001 to ,5 points 5001 to 10,000 2 points M Greater than 10,000 3 points filys 1 per 10,000 Point subtotal H (2) Average Dry Weather Flow (Design Capacity) Points (10 points Maximum) Less than MGD 0.5 point Greater than to 0.1 MGD 1 point Greater than 0.1 to 0.5 MGD 1.5 points Greater than 0.5 to 1.0 MGD 2 points E3 Greater than 1.0 MGD 3 points pjus 1 per 1 MGD Point subtotal 9 (3) Unit Process Points (Check all that apply) Preliminary Treatment and Plant Hydraulics: Comminution (includes shredders, grinders, etc.) 1 point Grit Removal, gravity 1 point El Grit Removal, mechanical 2 points Kl Screen(s), in-situ or mechanical 1 point E3 Pump/Lift Station(s) (pumping of main flow) 2 points Flow Equalization (any type) 1 point Point subtotal 5 Primary Treatment: D Community Septic Tank(s) 2 points Clarifier(s) 5 points Flotation Ciarifier(s) 7 points Chemical Addition System 2 points Imhoff Tank (or similar) 3 points Point subtotal 0 Total Points Page 1 25 Page 1 of 3 1 See "Population" definition. Use the design average daily per person load for Influent Flow or Influent BOD5, whichever is greater. This value Is also used to determine the Collection System Classification.

75 f *, Wastewater System Classification Worksheet Unit Process Points - Continued (Check all that apply) Secondary, Advanced, and Tertiary Treatment: Low Rate Trickling Filter(s) (no recirculation) 7 points High Rate Trickling Filter(s) (recirculation) 10 points Trickling Filter - Solids Contact System 12 points E3 Activated Sludge (any type) 15 points Pure Oxygen Activated Sludge 20 points D Activated Bio Filter Tower less than 0.1 MGD 6 points Activated Bio Filter Tower greater than 0.1 MGD 12 points D Rotating Biological Contactors 1 to 4 shafts 7 points Rotating Biological Contactors, 5 or more shafts 12 points Stabilization Lagoons, 1 to 3 cells without aeration 5 points Stabilization Lagoons, 1 or more cells with primary aeration 7 points Stabilization Lagoons, 2 or more cells with full aeration 9 points Recirculating Gravel Filter 7 points D Chemical Precipitation Unit(s) 3 points Gravity Filtration Unit(s) 2 points Pressure Filtration Unit(s) 4 points D Nitrogen Removal, Biological or Chemical/Biological System 4 points D Nitrogen Removal, Designed Extended Aeration Only 2 points Kl Phosphorus Removal Unit(s) 4 points Effluent Microscreen(s) 2 points Chemical Flocculation Unit(s) 3 points 13 Chemical Addition System(s) (6 points 2 points Point subtotal 21 Solids Handling: Anaerobic Primary Sludge Digester(s) w/o Mixing and Heating 5 points D Anaerobic Primary Sludge Digester(s) with Mixing and Heating 7 points D Anaerobic Primary and Secondary Sludge Digesters 10 points Sludge Digester Gas reuse 3 points Kl Aerobic Sludge Digester(s) 8 points Sludge Storage Lagoon(s) (or tanks, basins etc.) 2 points Q Sludge Lagoon(s) with aeration 3 points D Sludge Drying Bed(s) 1 point Sludge Air or Gravity Thickening 3 points Sludge Composting, In Vessel 12 points Kl Sludge Belt(s) or Vacuum Press/Dewatering 5 points Sludge Centrifuge(s) 5 points Sludge Incineration 12 points D Sludge Chemical Addition Unit(s) (alum, polymer, etc.) 2 points Non-Beneficial Sludge Disposal 1 point Kl Beneficial Sludge Utilization 3 points Point subtotal 16 Disinfection: Liquid Chlorine Disinfection 2 points Gas Chlorine Disinfection 5 points Dechlorination System 4 points K] Other disinfection systems incl. ultraviolet and ozonation 5 points Point subtotal 5 ODCertClassWorksheetrevS (10/9/03) Total Points Page 2 42 Page 2 of 3

76 Wastewater System Classification Worksheet (4) Effluent Permit Requirement Points (Check as applicable); Minimum of secondary effluent limitations for BOD and/or TSS 2 points Minimum of 20 mg/l BOD and/or Total Suspended Solids 3 points Minimum of 10 mg/l BOD and/or Total Suspended Solids 4 points Kl Minimum of 5 mg/l BOD and/or Total Suspended Solids 5 points Kl Effluent limitations for effluent oxygen 1 point Point subtotal 6 (5) Variation in Raw Waste Points. (6 points maximum) Points in this category will be awarded only when conditions are extreme to the extent that operation and handling procedure changes are needed to adequately treat waste due to variation of raw waste Recurring deviations or excessive variations 100% to 200% 2 points K] Recurring deviations or excessive variations of more than 200% or conveyance and treatment of industrial wastes by Pretreatment program 4 points Kl Septage or other hauled waste (control and/or preliminary treatment) 2 points Point subtotal 6 (6) Sampling and Laboratory Testing Points (check as applicable - maximum 11 points) Sample for BOD, Total Suspended Solids performed by outside lab 2 points Kl BOD or Total Suspended Solids analysis performed at treatment plant 4 points Bacteriological analysis performed by outside lab 1 point Kl Bacteriological analysis performed at WWT plant lab 2 points Nutrient, Heavy Metals or Organics analysis performed by outside lab 3 points Kl Nutrient, Heavy Metals or Organics analysis performed at WWT plant 5 points Point subtotal 11 ( 7 ) Points For Other Complexities Not Reflected Above: (see OAR (4) & (5)) Kl Odor Control (2 points maximum) 1 to 2 points M Standby Power 1 point Kl Solids Composting or Land Application of Biosolids 10 points Alkaline Stabilization (3 points maximum) 2 to 3 points Kl Other Effluent Limits [ammonia, CI2, temp,, etc. (list or attach 1 point D Pond(s) (advanced treatment polishing or irrigation holding) 2 points D Effluent Land Disposal - Evaporation (surface or subsurface) 2 to 4 points Effluent direct Reuse or Recycle 6 points Kl SCADA or similar for data (limited to extensive total process operation) 2 to 6 points Kl Chemical/Physical advanced waste treatment following secondary 10 points Chemical/Physical advanced waste treatment w/o secondary 15 points Biological or Chemical/Biological advanced waste treatment 12 points Reverse Osmosis, Electro-dialysis or Membrane Filtration techniques 15 points [X] Other complexities (list or attach list); filter 2 Point subtotal 27 Total Points Page 3 50 Total Accumulated Points (3 pages) 117 A COPY OF THIS COMPLETED WORKSHEET IS TO BE FILED WITH THE OPERATOR CERTIFICATION PROGRAM, WATER QUALITY DIVISION, PRIOR TO SYSTEM START-UP OpCertClassWorksheet.revS (10/9/03) Page 3 of 3

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