FACT SHEET And NPDES WASTEWATER DISCHARGE PERMIT EVALUATION

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1 FACT SHEET And NPDES WASTEWATER DISCHARGE PERMIT EVALUATION Department of Environmental Quality Western Region - Eugene Office 1102 Lincoln St., Ste. 210, Eugene, OR Telephone: (541) PERMITTEE: SOURCE LOCATION: SOURCE CONTACT: City of Gold Hill P.O. Box 308 Gold Hill OR File Number: Sardine Creek Road Lat ', Long ' Hydrocode: 15=-ROGU D Royal Gasso, Wastewater Plant Operator Telephone Number: Tony Paxton, City Hall, Recorder Telephone Number: PERMIT WRITER: Julie Berndt Telephone Number: x234 PROPOSED ACTION: Renewal of a National Pollutant Discharge Elimination System (NPDES) wastewater discharge permit SOURCE CATEGORY: TREATMENT SYSTEM CLASS: COLLECTION SYSTEM CLASS: Minor Municipal Level II Level II PERMIT APPLICATION DATE: August 1, 1997 PERMIT APPLICATION NUMBER: BACKGROUND Introduction The City of Gold Hill operates a wastewater treatment facility located in Gold Hill, Oregon. Wastewater is treated and discharged to the Rogue River in accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number (). The Permit for the facility was issued on August 7, 1992 and expired on July 31, The Department received a renewal application on August 1, 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,

2 City of Gold Hill Evaluation Report Page 2 L99?-D*Lo*mtv -Stwrt'jMlM USA Facility Description The City of Gold Hill operates a 0.35 million gallon per day (MGD) activated sludge sewage treatment plant. The City completed upgrading this plant on November 11, 1982, The design average dry weather flow for this wastewater treatment plant is 0.35 million gallons per day (mgd). The average seasonal effluent flows were for summer 1998 (May-Oct) 0,08 mgd and winter (Nov 1998-April 1999) 0.19 mgd. The peak effluent flows for the summer of 1998 occurred on August 4, 1998 (0.153 mgd) and winter on February 28,1999 (0.64 mgd). The plant consists of twin Cantex (donut type) treatment units. Raw sewage is pumped from the influent wet well up to the headworks (comminutor, manual bar screen and pista grit). The influent flow measurements and samples are taken just behind the bar screen and before a splitter box that diverts flows to the two treatment units. Each treatment unit has a treatment capacity of 175,000 gallons (gal). Influent flow passes through the contact stabilization basin and into the aeration basin. From there, the effluent goes to the secondary clarifier. Each unit has a center secondary clarifier (31,000 gal), aeration basin (48,000 gal), contact stabilization chamber (24,000 gal), duel aerobic digesters (32,500 gal each), and chlorine contract basin (7,000 gal). Currently, only the south treatment unit is operational, the north unit is in disrepair and is used solely for solids storage at this time. However, a review of the Discharge Monitoring Reports (DMRs) indicates that the wastewater treatment plant has not violated permit discharge limits due to lack of treatment capacity. Biosolids Management and Utilization The management of biosolids generated by the City of Gold Hill's treatment facility is regulated by the EPA Title 40 of the Code of Federal Regulations (CFR) Part 503 and Oregon Administrative Rule (OAR) Chapter 340 Division 50. The permittee has updated their biosolids management plan since the promulgation of 40 CFR 503 requirements in February The permittee's 1994 sludge management plan was approved on February 22, 1994.

3 City of Gold Hill Evaluation Report Page 3 There are no primary clarifiers in this treatment system. Secondary sludge is pumped to the aerobic digester from the clarifier. The duel digesters are aerated using course bubble diffusers. Solids are held in the south treatment digester for a minimum of 30 days at ambient temperatures. The sludge is then transferred to the north treatment unit for further storage. The SRT in the aerobic digesters is 55 to 100 days. Digested biosolids meet Class B Processes to Significantly Reduce Pathogen (PSRP) time requirement before they are trucked (1500 gal Tank Truck) and land application on farmland. Beneficial land application is performed year round on Department approved sites. The average solids concentration produced by the plant digestion process is less than 2%; the average volatile solids reduction is about 41%, The treatment plant generates about 360,000 gallons of liquid biosolids or 40 dry tons of biosolids per year. Class B biosolids are land applied at beneficial rates (100 lb, Total N/acre) on over 60 acres of farmland). Beneficial land application is performed year round on Department approved sites. The City needs sixteen acres of farmland to accommodate all the nitrogen they generate in their biosolids. Currently the City uses two primary sites, one located on the Phillips ranch in Gold Hill (2.5 acres winter, 20 acres summer) and the other on the Watson property in Gold Hill (6 acres summer). The current approved agronomic loading rate for biosolids on these application sites are 100-lb. total nitrogen per acre. The permittee conducts chemical testing of biosolids to be land applied which includes analysis of metals. The latest monitoring data, from a sample taken is found below: Parameter Arsenic Cadmium Chromium Copper Lead Mercury Molybdenum Nickel Selenium Zinc ;13 Table 3 Limit 41 mg/kg 39 mg/kg 1200mg/kg 1500 mg/kg 300 mg/kg 17 mg/kg 18 mg/kg 420 mg/kg 36 mg/kg 2800 mg/kg It can be seen form the above table that the biosolids meet the requirements of Table 3 limits. A review of the past seven biosolids analysis had all the Molybdenum (Mo) results below the test detection limit (typically 0.2 mg/l) except for the 1998 analysis which was 19 mg/l. It is believed the 1998 Mo test result is a spurious result. Inflow and Infiltration (I/I) Schedule B of the proposed permit contains a condition requiring the permittee to implement an Inflow and Infiltration Program, Included in this program will be the requirement to submit an annual report to the Department. The City is currently working toward repairing older sections in the downtown collection system (5 th and 6 (h Street). Pretreatment The City does not have a formal pretreatment program. There are no categorical industries discharging to the system and the facility is not experiencing toxic upsets. Therefore, there is no industrial pretreatment survey recommended for this permit renewal.

4 City of Gold Hill Evaluation Report Page 4 Pollutants Discharged The current permit allows Gold Hill to discharge treated effluent from the wastewater treatment plant all year, The current permit sets limits on the following pollutants as follows: Junel-Oct. 31 Parameter BOD 5 TSS E. coli Bacteria Nov. 1-May 31 Parameter BOD 5 TSS E. coli Bacteria Monthly Ave. ;:Em : conc. : j : ; : - :;: ;: Weekly Ave. EfLConc.'':7:: Mass Load Monthly Ave. ib./day Mass Load Weekly Ave, ib./day Mass Load ; ;: DailyAve, Ib./day Shall not exceed 126 organisms per 100-ml monthly geometric mean. No single sample shall exceed 406 organisms per 100 ml Monthly Ave. Elf. Cone Shall not exceec sample shall exc Weekly Ave. Eff. Cone Mass Load Monthly Ave. lb./day Mass Load Weekly Ave. lb./day Mass Load Daily Ave. Ib./day organisms per 100-ml monthly geometric mean. No single eed 406 organisms per 100 ml Outfalls Treated wastewater is discharged year around through a 12-inch pipe to the Rogue River, This section of the Rogue is fairly wide with even flows. Receiving Streams/Impact The water quality standards for the Rogue Basin (Oregon Administrative Rules are intended to be protective of the beneficial uses for the basin. Treated wastewater is discharged to the Rogue River at river mile OAR (Table 5) lists the beneficial uses for which water quality will be protected. Included in Table 5 for the Rogue are: Public domestic water supply, Private domestic water supply, Industrial water supply, Irrigation, Livestock watering, Anadromous fish passage, Salmonid fish rearing, Salmonid fish spawning, Residentfishand aquatic life, Wildlife and hunting, Fishing, Boating, Water contact recreation, and Aesthetic quality

5 City of Gold Hill Evaluation Report Page 5 Applicable water quality standards for the Rogue River are found in OAR The Oregon draft 1998 List of Water Quality Limited Water Bodies (303(d) List), lists Rogue River as Water Quality Limited for the following parameters: Assessment Parameter Bacteria Temperature Season Summer Summer The Rogue River either meets criteria for other parameters or there is not enough information available to rationalize a listing. The Department expects to complete the Rogue River TMDL in the year This permit will be renewed in the year 2005 and the requirements of the Rogue River TMDL will be incorporated into the permit at that time. This permit does, however, contain monitoring requirements to collect information that will assist in TMDL development. Mixing Zone The current permit allows a mixing zone of that portion of the Rogue River 10 feet up river from the point of discharge and 200 feet downstream from the point of discharge. OAR l-365(4)(c)(b) states that the mixing zone shall be less than the total stream width as necessary to allow fish passage, However, the Department does not currently have enough information to determine the actual mixing zone. Therefore, the proposed permit contains an interim mixing zone of that portion of the Rogue River that is one-half the width of the stream from ten feet above the point of discharge to 200 feet downstream. Schedule C of the proposed permit requires City of Gold Hill to perform an effluent mixing zone dilution study to evaluate the dilution in the mixing zone and to recommend a mixing zone that satisfies OAR l-365(4)(c)(b). Upon receipt of additional mixing zone information, the Department may reopen the NPDES permit to modify the interim-mixing zone and include additional effluent limitations or conditions as necessary to meet permit requirements and Oregon regulations. For critical condition water quality modeling, the EPA recommends using the minimum seven-day average flow with a ten-year recurrence (7Q10). The monthly 7Q10s were calculated based on the data from USGS gage # , Rogue River at Grants Pass, Oregon. The 7Q10s are shown below: Rogue River 7Q10 Values By month for Str 100 oa 800 m Flo iifi/ rc.i 38" -338 r - T S 7 B _ Hf/l 1132 J37 M<) ;K/ I7Q10 w BOO i 200 i... L' S Month

6 City of Gold Hill Evaluation Report Page 6 As can be seen from the above chart, the critical low flow condition for the low flow season (May-October) and high flow season (November-April) occur in October and November respectively. Therefore, for the purposes of this evaluation, the lowflowseason 7Q10 is 940 cfs and the highflowseason 7Q10 is 1050 cfs. Analysis of Water Quality Limited Parameters - Bacteria The basis of the water quality limited listing for bacteria for the Middle Rogue is that twelve percent of the samples analyzed exceed the fecal coliform criteria of 400 organisms per 100 ml. The effluent has been consistently below the water quality standard for bacteria. Therefore, the discharge is not causing the bacteria standard exceedences. Analysis of Water Quality Limited Parameters - Temperature Elevated instream temperatures are detrimental to cold water fish, OAR l-0365(2)(b)(A) sets the standard for temperature in the Rogue River Basin. This standard restricts surface water temperature increases resulting from anthropogenic activities under certain environmental conditions (OAR (2)(b)(A)). Department policy states that the following mass balance equation for temperature should be used for conducting an analysis to determine if the discharge creates a measurable temperature increase at the edge of the mixing zone: Where: T 111Z = [(T E + DT.)]/(D+ 1) D is the calculated or measured dilution at the edge of the mixing zone; T s is the applicable temperature criteria; T E is the effluent temperature in F; and T roz is the temperature of the stream at the edge of the regulatory mixing zone in F This equation assumes that temperature is a conservative parameter. This assumption should be acceptable for most analysis since only near-field analysis is being conducted. In this area, mixing with the stream accounts for most of the reduction in effluent temperature. The City of Gold Hill does not collect temperature data. However, data collected by other treatment facilities in the area indicate that summer effluent temperatures are about 75 F. Using this value and assuming a mixing of 20 percent of the stream, the evaluation is as follows: D = [0.20*940] / [0.35*1.547] = 340 T,z = [(T B + DT,)] / (D + 1) = [ *434] / [ ] = iiiz 0* *U«3 The Department considers 0.25 F measurable. Therefore, if the stream were at the temperature standard (64 F), the discharge would not cause a measurable increase above the standard at the edge of the mixing zone. However, because the receiving stream is listed on the 303(d) list as water quality limited for temperature, the permittee has submitted a Temperature Management Plan (TMP), which the Department proposes to approve with this permit action. Groundwater All the units in the Gold Hill facility are made of concrete. There are no groundwater concerns provided that proper design, operation, and maintenance occurs to this facility's structures and under ground piping. The proposed permit includes a narrative prohibiting adverse impacts on groundwater.

7 City of Gold Hill Evaluation Report Page 7 Stormwater Under current Department rules, facilities with an average dry weather design flow of less than 1 MGD are not required to obtain a stormwater permit. Compliance History Since the current issued permit, August 7, 1992 the City of Gold Hill has received six (6) Notices of Noncompliance (NON) and a Notice of Permit Violation (NPV) from the Department. This facility was last inspected on September 26, Violations were found and a NON was issued. Date-:-. November 5,1992 November 30,1992 December 15,1992 March 2, 1993 April 28,1995 December 10,1998 September 26,2000 \NON^^^'i ; ; -::: : :, ; "::,~ : -.: :: :: NON-SWR NON-SWR NPV WQMW-SWR NON~SWRr048 NON-WQ-WRM NON-WR-RSB NON-WR-RSB Violation Fabricated test results No designated operator of record, missed monitoring testing, unauthorized sludge disposal No designated operator of record, missed monitoring testing, unauthorized sludge disposal Missed TSS tests BOD and TSS cone, and percent removal exceedences Missed ph tests Failure to submit 1999 annual Biosolid report, failure to have certified. Operator and lack of plant maintenance. The above violation or violations are 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. PERMIT DISCUSSION Face Page The permittee is authorized to construct, install, modify, or operate a wastewater collection, treatment, control and disposal system. Treated effluent is permitted to be discharged to the Rogue River within limits set by Schedule A and the following schedules. All other discharges are prohibited. This facility discharges to Rogue River at river mile year-round. The outfall is designated as 001 and has a hydrocode of 15-ROGU D. Treatment and collection systems are classified on size and complexity. There have been no changes in the operational size and complexity of the Gold Hill system. Therefore the classification of the systems in the purposed permit will remain as Class II treatment and Class II collection. Schedule A - Waste Discharge limitations Title 40 Code Federal Regulations (40 CFR) Part 133 establishes minimum federal secondary sewage treatment requirements. 40 CFR identifies monthly and weekly average concentration limits, and monthly average percent removal efficiency limitations for Biochemical Oxygen Demand (BODS), Carbonaceous Biochemical Oxygen Demand (CBOD5), Total Suspended Solids (TSS), and ph effluent parameters. As an NPDES delegated state, Oregon is required to implement 40 CFR 133 and therefore these limitations are part of the draft permit.

8 City of Gold Hill Evaluation Report Page 8 The waste discharge limitations are based on the Rogue Basin water quality standards: OAR (9)(a) Basin Beneficial Water Uses to be Protected, OAR Water Quality Standards Not to be Exceeded, and OAR Minimum Design Criteria. For the last five years, the permittee has generally met the effluent limitations of the current permit. Compliance inspections have shown the facility to do not comply with operations and maintenance requirements. The Department ran a Streeter Phelps dissolved oxygen model on the Gold Hill discharge. The results of this model indicate the effluent does not adversely affect the DO concentrations in the receiving stream during 7Q10 conditions. The model shows a maximum DO sag of.4 mg/l (96% saturation) at a distance of 27.4 miles down stream. BOD and TSS concentration and mass limits (Outfall 001) Biochemical Oxygen Demand (BOD) is exerted on natural streams by the biological activity. Food sources such as municipal effluent increase the biological activity and therefore increase the BOD. These sources include materials such as ammonia which create a biochemical oxygen demand known as nitrogenous biochemical oxygen demand (NBOD). When the biochemical oxygen demand test is run with a nitrification inhibitor, the resulting oxygen demand is assumed to be totally due to carbon sources and is called carbonaceous biochemical oxygen demand (CBOD). Based on the Rogue Basin minimum design criteria, wastewater treatment resulting in a monthly average effluent concentration of 10 mg/l for BOD s and TSS must be provided from May 1 - October 31. From November 1 - April 30, a minimum of secondary treatment or equivalent control is required. Secondary treatment for this facility is defined as monthly average concentration limit of 30 mg/l for BOD 5 (or 25 mg/l for CBOD 5 ) and 30 mg/l for TSS. Because the facility has not upgraded the secondary treatment capacity of the WWTF, the Department is proposing concentration limits that are the same as the current permit. The WWTF will be required to meet the basin minimum design criteria when the secondary treatment capacity is increased. The proposed monthly average summer BODs concentration limit is 20 mg/l with a weekly average limit of 30 mg/l. The proposed monthly average summer TSS concentration limit is 20 mg/l with a weekly average limit of 30 mg/l. The proposed monthly average winter BOD 5 concentration limit is 30 mg/l with a weekly average limit of 45 mg/l. The proposed monthly average winter TSS concentration limit is 30 mg/l with a weekly average limit of 45 mg/l. The summer mass limits for biochemical oxygen demand (BOD5) and suspended solids (TSS) are based on the design average diy weather flow (ADWF) of 0.35 MGD and the monthly average BOD5 and TSS concentration limits of 20 mg/l and 20 mg/l, respectively. While OAR (9)(a) requires mass loads to be based on design average wet weather flow (DAWWF), the Department does not have any information on the design wet weather flow for this facility. Therefore the winter mass load limits in the purposed permit are based on the design ADWF and there is a condition in Schedule C requiring submission of an engineering study determining the design average wet weather flow. The monthly average BOD 5 or TSS concentration limits of 30 mg/l and 30 mg/l, respectively, The limits are in accordance with OAR (9)(e). All mass load limitations are rounded to two significant figures, Should the permit be modified to base the winter mass limits on AWWF, the permittee will be required to remove all inflow sources from the collection system, The proposed permit includes a Schedule C condition requiring submittal of a program and time schedule for identifying and removing inflow.

9 City of Gold Hill Evaluation Report Page 9 The limits are: (1) May 1-October 31: Average Effluent Concentrations Parameter Monthly BOD 5 20 mg/l TSS 20 mg/l Weekly 30 mg/l 30 mg/l Monthly Average lb/day Weekly Average lb/day Daily Maximum Lbs (2) November 1 - Ai >ril 30: Average ; Effluent Concei itrations Parameter BOD 5 TSS Monthly 30 mg/l 30 mg/l Weekly 45 mg/l 45 mg/l Monthly Average lb/day Weekly Average lb/day Daily Maximum Lbs (1) (2) Summer BOD 5 /TSS (a) 0.35 MGD x 8.34 #/gal x 20 mg/l monthly avg. = 58 lbs/day (b) 58 lbs/day monthly avg. x 1,5 = 88 lbs/day weekly avg. (c) 58 lbs/day monthly avg. x 2.0 = 120 lbs/day daily max. Winter BOD5 TSS (a) 0.35 MGD x 8.34 #/gal x 30 mg/l monthly avg. = 88 lbs/day (b) 88 lbs/day monthly avg. x 1.5 = 130 lbs/day weekly avg. (c) 88 lbs/day monthly avg. x 2.0 = 180 lbs/day daily max. A review of recent monitoring data indicates the City should generally be able to comply with the permit limits. BOD and TSS Percent Removal Efficiency A minimum level of percent removal for BOD5 and TSS for municipal dischargers is required by the Code of Federal Regulations (CFR) secondaiy treatment standards (40 CFR, Part 133). An 85 percent removal efficiency limit is included in the proposed permit to comply with Federal requirements. An examination of the DMR data indicates the permittee will have little difficulty meeting the limit with the current facilities. El The Rogue Basin Water Quality Standard for ph is found in OAR 340-4l-0365(2)(d). The allowed range is 7.0 to 8.5. The proposed permit limits ph to the range 6.0 to 9.0. This limit is based on Federal wastewater treatment guidelines for sewage treatment facilities, 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. Bacteria The proposed permit limits are based on an E. coli standard approved in January 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

10 City of Gold Hill Evaluation Report Page 10 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 proposed effluent limits are achievable through proper operation and maintenance. Toxics The Department has developed spreadsheets to determine if there is a reasonable potential for the discharge to exceed toxicity criteria and to determine effluent limitations for those parameters that do. Because there is no mixing zone dilution study available actual dilutions are unknown. Therefore, the Department performed the analysis by estimating the dilution at the edge of the mixing zone as 20% of the stream flow and dilution at the edge of the zone of immediate dilution as 5% of the stream flow (see attached spreadsheet). This evaluation showed that there is likely no reasonable potential to exceed the chlorine criteria. However, there is no information on ammonia and a better determination of the actual dilution is needed. Therefore, Schedule B of the purposed permit contains ammonia-monitoring requirements and Schedule C of the purposed permit contains a condition requiring submission of a mixing zone dilution study. Temperature Because the Rogue is water quality limited for temperature, OAR (3)(a)(D) requires anthropogenic sources to develop and implement surface water temperature management plans (TMP) that describe the best management practices, measures, and/or control technologies that will be used to reverse the warming trend. The Department approved TMP is included as an attachment to this permit. The Department approved TMP evaluation has determined that it is unlikely that the discharge will cause a measurable increase in the stream temperature at the edge of the mixing zone. In this instance, Department policy is that the TMP does not need to have a requirement to evaluate temperature reduction strategies. Compliance with the NPDES permit limits, monitoring and reporting requirements, and the Department approved TMP satisfies the requirement for compliance with the temperature standard. Department policy requires effluent limitations and a prohibition against an increase in the thermal loading for heated discharges to water quality limited streams. For municipal sources, the excess thermal loading (the portion in excess of the instream standard) is based on the design flow of the treatment plant, Therefore, the proposed permit establishes a limit based on the design average dry weather flow (0.35 mgd) as follows: Excess Thermal Loading = flow x AT x 8.34 = 350,000 x (75-64) x 8.34 = 32 million BTU This limit is included in Schedule A of the permit, Schedule D of the proposed permit contains a condition requiring Gold Hill to obtain a permit modification before increasing the thermal load. Schedule B - Minimum Monitoring and Reporting Requirements The authority to require reporting by permittees is included under ORS 468,065(5). The proposed monitoring frequencies for all parameters are based on the Department's monitoring matrix and are generally uniform for facilities of similar size and complexities. The Department is also proposing to include in the opening paragraph of Schedule B a statement recognizing that some selfmonitoring test results may be inaccurate, invalid, or do not adequately represent the facility's performance. When that is the case, the faulty data is not to be used in calculations or compliance determinations required by the permit. In order to collect information needed to develop the Rogue River TMDL the Department has included nutrient and temperature monitoring requirements. Nutrient sample will be once monthly during the low flow season for three years after

11 City of Gold Hill Evaluation Report Page 11 permit issuance. Temperature monitoring will be daily year round, The permittee may use data loggers. This requirements are part of the Department approved TMP, 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 City 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 also includes the requirement for the submittal of annual reports. The conditions are standard language requirements concerning: 1) Inflow and Infiltration 2) Biosolids Schedule C - Compliance Conditions The draft permit contains five compliance conditions for the submittal and implementation of the following items: (1) Wet weather design flow determination, (2) Inflow and Infiltration reduction program, (3) Mixing zone dilution study for effluent toxicity, (4) Bypass identification program, and (5) Notification requirement. A condition that the permittee is expected 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 proposed permit containsfive (5) special conditions concerning: (1) Increases in thermal loading, (2) Biosolid management plan requirement, (3) Contingency to modify permit to incorporate new biosolids standards, (4) Operator certification, and (5) General conditions 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. 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, If the permit applicant 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.

12 CITY OF GOLD HILL TEMPERATURE MANAGEMENT PLAN 1, INTRODUCTION This temperature management plan (TMP) is prepared in accordance with Oregon Administrative Rules (OAR) l-0026(3)(a)(d). This rule requires anthropogenic sources to develop and implement a TMP when the receiving stream for a permitted discharge is listed on the Department's 303(d) list as being water quality limited for temperature. The purpose of water quality standards are to protect the beneficial uses of waters of the state. The beneficial uses most sensitive to water temperatures are fish and aquatic life and, therefore, the temperature standard is based on protecting these beneficial uses. Treatment Facility Description The City of Gold Hill operates an activated sludge sewage treatment plant. The plant discharges treated effluent to the Rogue River at River Mile The design average dry weather flow for this wastewater treatment plant is 0.35 million gallons per day (mgd). The average seasonal effluent flows were for summer 1998 (May- Oct) 0.08 mgd and winter (Nov 1998-April 1999) 0.19 mgd. The peak effluent flows for the summer of 1998 occurred on August 4, 1998 (0.153 mgd) and winter on February 28,1999 (0.64 mgd). The Oregon draft 1998 List of Water Quality Limited Water Bodies (303(d) List), lists Rogue River as Water Quality Limited for the following parameters: Assessment Parameter Bacteria Temperature Season Summer Summer The Department expects to complete the Rogue River TMDL in the year Gold Hill's permit is expected to be renewed by the Department in the year 2005 and the requirements of the Rogue River TMDL will be incorporated into the permit at that time. 2. SEASONAL PRESENCE AND LIFE STAGES OF SALMONIDS The seasonal presence and life stages of salmonid species, especially those stocks that are listed as threatened or endangered, are included in the following table which has been created to provide information specific to the Rogue River and the reach near Gold Hill's sewage treatment plant outfall.

13 Gold Hill TMP Page 2 Table 2-1. Salmonid Species Specific to the Rogue River Basin Species Runs Run Timing Life Stage Notes Chinook (fl) Spring March - July Returning adults Migrating through the area. September - October Spawning Spawn ~ > 25 miles above the area. March - November Rearing Including out-migration of smolts. Fall July - October Returning adults Migrating to/above the area. October - December Spawning Spawn in the main stem area. March - November Rearing Rear in the area and out-migrate through the area. Coho (b) Fall September - December Returning adults Migrating through the area. November - February April - June Spawning Rearing and out-migrating Spawn in upper tribs. Rear in upper tribs, juveniles could be in the area. Steelhead (c) Summer April - June Returning adults Spawn in tribs, rear in mainstream. Migrate/rear/out-migrate through the area. Winter December - May Returning adults Migrate through the area. February - May Spawning Spawn in upper tribs. July- Deeember Rearing and out-migrating Out-migrate through the area. Cutthroat (d) Resident Year round All No evidence that sea-run cuts use reach the area. Resident Cutthroat spawn from December - May. (A) w tc) Southern Oregon and Northern California Coastal Chinook Evolutionarily Significant Unit (ESU) (currently not warranted for listing) Northern California and Southern Oregon Coastal Coho ESU (currently listed as threatened) Klamath Mountains Province Steelhead ESU (currently a candidate for listing) (d) Southern Oregon and California Coast Cutthroat Trout ESU (currently not warranted for listing)

14 Gold Hill TMP Page 3 Comments specific to the Endangered Species Act (ESA) or the discharge location include: Fall Chinook spawn in the vicinity of the area, Chinook are not warranted for protection under the Endangered Species Act (ESA); however, state criteria for spawning salmonids applies, Fall Coho out-migrate through the area as late as June. Coho are listed as threatened under the ESA. Winter steelhead rear and out-migrate through the area throughout the summer into late fall. Winter steelhead are a candidate for listing under the ESA, Applicable temperature criteria based on salmonid presence and life stages The spawning temperature criteria of 55 F applies for the months of September through December (when salmonid species are spawning, incubating or emerging). No measurable increase (0.25 F) above ambient stream temperature outside of the mixing zone applies when T&E species are present. The rearing temperature criteria of 64 F applies during the rest of the year. No measurable increase (0.25 F) above temperature standard outside of the mixing zone applies when ambient stream temperature exceeds the standard. 3. DEVELOPMENT OF CURRENT SITE SPECIFIC DATA SETS AND A TEMPERATURE MONITORING PLAN There currently is little temperature data available to evaluate for Gold Hill's discharge. In order to prepare for the TMDL and the possibility of a waste load allocation, the City of Gold Hill proposes the following temperature monitoring program to be incorporated into the NPDES permit renewal: Sewage Treatment Plant Effluent ^S:^-vrvi^^:Item^i;or^Patajmet# ^.' ; Total Flow (MGD) Temperature Thermal Loading (7 day avg.) Minimum Frequency Daily Daily Daily Type of Sample Measurement Record Calculation Seven day average thermal loading will be calculated based on the weekly average temperature and effluent flow and the 64 F criteria as follows: Thermal Loading =flow (gpd) x(t - 64) x The renewal permit needs to establish an effluent limitation on excess thermal load and a prohibition against an increase in the thermal loading. For municipal sources, the thermal loading is based on the design flow of the treatment plant. Therefore, the proposed permit limit is based on the design average dry weather flow (0.35 mgd) and an estimated discharge temperature of 75 degrees as follows: Thermal Loading =flow x AT x8j4 = 350,000 x (75-64) x8.34 = 32 million BTU

15 Gold Hill TMP Page 4 4. DESCRIPTION OF PHYSICAL CONDITIONS OF EFFLUENT MIXING AND DILUTION OF EFFLUENT IN THE RECEIVING STREAM The current permit allows a mixing zone of that portion of the Rogue River ten feet up river from the point of discharge and 200 feet downstream from the point of discharge. OAR 340-4l-365(4)(c)(B) states that the mixing zone shall be less than the total stream width as necessary to allowfishpassage. There is currently not enough information for the Department to determine the actual mixing zone. The proposed permit renewal contains an interim mixing zone of that portion of the Rogue River that is one-half the width of the stream from ten feet above the point of discharge to 200 feet downstream. Schedule C of the proposed permit requires the City of Gold Hill to perform an effluent mixing zone dilution study to evaluate the dilution in the mixing zone and to recommend a mixing zone that satisfies OAR (4)(c)(B). Upon receipt of additional mixing zone information, the Department may reopen the NPDES permit to modify the interimmixing zone and include additional effluent limitations or conditions as necessary to meet permit requirements and Oregon regulations. For critical condition water quality modeling, the EPA recommends using the minimum seven-day average flow with a ten-year recurrence (7Q10). The monthly 7Q10s were calculated based on the data from USGS gage # , Rogue River at Grants Pass, Oregon. The 7Q10s are shown below: Table 4.1 Rogue RIver7Q10 Values By month for T 1200 Stream 1000 " Mow C" T I n > > i " -"fit ) is rr 1132 I7Q Month As can be seen from the above chart, the critical low flow condition for the low flow season (May-October) and high flow season (November-April) occur in October and November respectively. Therefore, for the purposes of this evaluation, the low flow season 7Q10 is 940 cfs and the highflowseason 7Q10 is 1050 cfs.

16 Gold Hill TMP Page 5 5. ANALYSIS OF DISCHARGE TEMPERATURE IMPACT ON THE RECEIVING STREAM Elevated instream temperatures are detrimental to cold-water fish. OAR (2)(b)(A) sets the standard for temperature in the Rogue River Basin. This standard restricts surface water temperature increases resulting from anthropogenic activities under certain environmental conditions (OAR l-0365(2)(b)(A)). Department policy states that the following mass balance equation for temperature should be used for conducting an analysis to determine if the discharge creates a measurable temperature increase at the edge of the mixing zone: Where: T mz =[(T E + DT s )]/(D + l) D is the calculated or measured dilution at the edge of the mixing zone; Ts is the applicable temperature criteria; TE is the effluent temperature in F; and T ra j; is the temperature of the stream at the edge of the regulatory mixing zone in F. This equation assumes that temperature is a conservative parameter. This assumption should be acceptable for most analysis since only near-field analysis is being conducted. In this area, mixing with the stream accounts for most of the reduction in effluent temperature. The City of Gold Hill was not required to collect temperature data in the existing permit. However, data collected by other treatment facilities in the area indicate that summer effluent temperatures are about 75 F. Using this value and assuming mixing with 20% of the stream (Less than Vi of the allowed mixing zone), the evaluation is as follows: D = [0.20*940] / [0.35*1.547] = 340 Tmz = [(TE + DT S )] / (D + 1) - [ *434] / [ ] = T raz = These values are considered to be very conservative. Less than l A of the allowed mixing zone is used in the calculation, and an assumed extreme high temperature for the relatively small discharge to the receiving stream. The Department considers 0.25 F measurable. Therefore, if the stream were at the temperature standard (64 F), the discharge would not cause a measurable increase above the standard at the edge of the mixing zone.

17 Gold Hill TMP Page SUMMARY Because the Rogue is water quality limited for temperature, OAR (3)(a)(D) requires anthropogenic sources to develop and implement surface water temperature management plans that describe the best management practices, measures, and/or control technologies that will be used to reverse the warming trend. However, this evaluation, which is based on Department guidance, has determined that it is unlikely that the discharge will cause a measurable increase in the stream temperature at the edge of the mixing zone. In this instance, Department policy is that the temperature management plan need only contain monitoring requirements. While the plan does not need to have a requirement to evaluate temperature reduction strategies at this time, the City is aware that the Rogue River TMDL may establish a waste load allocation on thermal discharges that are lower than allowed under the renewal permit. Compliance with the NPDES permit limit and monitoring satisfies the requirement for developing and implementing the surface water temperature management plan.

18 Attachment A March 2002 Biosolid Management Plan for The City of Gold Hill. File Number: I. Treatment Facility Introduction: The City of Gold Hill owns a wastewater collection system and a 0.35-mgd (average dry weather flow) activated sludge wastewater treatment plant (WWTP). The City operates this facility under NPDES Permit Number #100951, Aside from the City's residential population, the WWTP processes wastewater generated by grade and high schools, several restaurants, a laundromat and other commercial establishments. Currently the average summer flows are about 100,000 gallons per day of which 95% is domestic and 5% is commercial. There are no significant industrial users or septage discharges to the sewerage system of Gold Hill. Treated effluent from the WWTP is disinfected before being discharged to Rogue River (River Basin: Rogue; Hydro Code 15=-ROGU D). A) Wastewater Processing: The wastewater treatment works is comprised of two 175,000-gallon per day capacity sewage treatment units of duplicate design, Currently the south treatment unit is used for wastewater treatment and the north unit is used for solids digestion and storage. Each wastewater treatment system consists of a wet well, aeration basin (54,000 gallons), secondary clarifier (31,000 gallons), two aerobic digesters (32,000 gallons), a contact stabilization chamber (24,000 gallons), and chlorine disinfection chamber (7,000 gallons). B) Solids Processing: There are no primary clarifiers. Solids removed from the secondary clarifier and transferred to one of the two aerobic digesters for digestion. When a digester is full, the air is turned off allowing solids to settle. Supemate is decanted back to the wet well. The solids are then re-aerated. When a digester is full of solids, they are transferred to the north treatment unit. Solids are held in the primary digester until the digester is full, up to 30 days. Solids are initially digested in the south unit then transferred to the north for further digestion (up to 55 to 100 days). The primary digester operates at 15 to 17 degrees Celsius, depending on the ambient temperature. The treatment plant generates about 360,000 gallons of solids or approximately 27 dry tons of biosolids.

19 City of Gold Hill Biosolid Management Plan March 18, 2002 Page 2 of9 (0.0268% TS)(8.34 lbs./gallon H 2 0)(360,000 gallons/year)/(20001bs/ton) = diy tons biosolids per year. C) Solids Storage Structure: The storage capacity of the north unit's two aerobic digesters is 64,000 gallons; in addition, this unit has a 54,000-gallon aeration basin, and 24,000-gallon contact chamber to aerate and store solids, The North unit provides several months of additional storage. D) Septage Receiving Facility: No septage is received at the City of Gold Hills wastewater facility. F) Pretreatment Program: The City of Gold Hill's ordinances through prohibits certain wastes in sanitary sewers, and account for some preliminary treatment, preliminary treatment facilities, right of entry, and testing. II Solid Treatment Processes: The EPA's 40 CFR Parts 503 and the DEQ's OAR allow permittees to use EPA approved alternatives to satisfy Class A and B biosolid pathogen or vector attraction reduction criteria. The permittee must notify the Department in writing and get approval prior to any process change that would utilize pathogen reduction and/or vector attraction reduction alternatives other than their primary reduction alternatives contained in this management plan. The permittee must also certify that the alternatives used are EPA approved and that sampling and monitoring conforms to the 40 CFR 503 and OAR regulations. Pathogen Reduction: To meet the Part 503 regulatory requirements pathogen reduction must be met before vector attraction reduction or at the same time vector attraction reduction is achieved. Class B Biosolids: Class B biosolids can be met by using one of three alternatives, the two primary alternatives used by this facility are Alt. 1) Monitor sewage sludge for fecal coliform (b)(2), and Alt. 2) Use Process to Significantly Reduce Pathogen (PSRP) (b)(3). Alt. 1) Monitor sewage sludge for fecal coliform (b)(2) requires that seven samples of treated sewage sludge (biosolids) be collected and that the geometric mean fecal coliform density of these samples be less than 2 million MPN per dry gram biosolid (dry weight basis).

20 City of Gold Hill Biosolid Management Plan March 18,2002 Page 3 of9 Alt. 2) Use Process to Significantly Reduce Pathogen (PSRP) (b)(3) considers sludge treated in one of the PSRPs listed in Appendix B of the Part 503 to meet Class B biosolid criteria for pathogen reduction. For this facility the following PSRPs are primarily used: PSRP # 3) Aerobic digestion, sludge is agitated with air or oxygen to maintain aerobic conditions for a specific mean cell residence time at a specific temperature. Values of the mean cell residence time and temperature shall be between 40 days at 20C (68F) to and 60 days at 15C (59F). B) Vector Attraction This facility primarily uses the following vector attraction reduction options: Opt. 1) The % volatile solid reduction calculation to use for anaerobic digester that is decanted and that does not have appreciable grit accumulation would be the Van Kleeck or Approximate Mass balance (AMB) equation depending upon the percent solids in the decantante (Attachment C). To meet the biosolid vector attraction reduction requirements an aerobic digester must provide a 40-day detention time at 20C in a completely mixed digester in order to achieve a volatile solids reduction of 38 % or more. There are alternative volatile solid reduction methods that are deemed equivalent to the 38% volatile solid reduction criteria under the EPA's and the DEQ's regulations. Opt 3) Less than 15% additional volatile solid loss during bench-scale aerobic batch digestion of the sewage sludge for 30 additional days at 20C (68F). Ill Biosolid Characteristics: Gold Hill's treatment works utilizes an activated sludge process, The treatment facility wastes activated sludge from the secondary clarifiers to aerobic digesters. The sludge undergoes a minimum of 40-days of digestion at a minimum temperature of 20 C and additional (up to 100 days) digestion at ambient. For the past five years the average volatile solids reduction criteria has been achieved by the Gold Hill wastewater treatment facility. Annually, Gold Hill had generated approximately 27 dry US tons of biosolids. Monitoring: Gold Hill produces approximately 24 diy metric tons of biosolid each year. Under the 40 CFR Part 503, Gold Hill is required to sample biosolid once a year. Frequency of monitoring depends on the amount of biosolid generated that is marketed to be sold or given away, land application and surface disposal Frequency depends on the amount of

21 City of Gold Hill Biosolid Management Plan March 18, 2002 Page 4 of9 bulk biosolid applied to the land, or the amount of sewage sludge received by a person who prepares biosolid that is sold or given away in a bag or other container for application to the land (dry weight basis), or the amount of biosolid (excluding domestic septage) placed on a surface disposal site, Sampling Locations: Sample aerobic digesters' inlet and outlet lines to digesters. Number and type of sample taken per day: Composite of discrete samples collected throughout the sampling period. Sample storage and transport: Samples are stored at 4 C in ice chest or refrigerator. Samples are transported in ice chest to maintain temperature during delivery to laboratory. Pathogen samples are delivered to lab within one hour of sample collection. Sample analysis method: EPA 9045; EPA 160.3;EPA 160.4; SM 4500-NH3B; EPA 353.2; EPA 365.3; EPA 351.3; SW ; SW ; SW-846; SW ; SW ; SW ; SM 18 th, 9221E.1; SM 18:9260D.l; ASTM D ; EPA 600/1-87/014; EPA 8240; EPA 1613; EPA 8270; EPA 1613B; EPA 1668(may include one or more of the referenced methods) Biosolid Analysis: Biosolid Chemieal Analysis: From the Gold Hill's 2001 biosolids analysis the following is a representative sampling of the biosolid metal concentration. Pounds(lb.) lb. lb. lb, lb. lb. lb. lb. lb. lb. Metal Arsenic (As) Cadmium (Cd) Chromium (Cr) Copper (Cu) Lead (PB) Mercury (Hg) Molybdenum (Mo) Selenium (Se) Zinc (Zn) Ib.-ton/yr ,3 0, lb./acre-yr site life The site life would be limited to (1857) years based on the Zinc loading Gold Hill's 2001-biosolid analysis (Attachment B). Biosolid Nutrient Analysis: For the year 2001, these dewatered biosolids contained about (884) pound (lb.) total nitrogen (N) of which about (0.5) lb. is in the nitrate form (N03-N02) and (96) lb. is in the ammonia form (NH3), and has a ph of approximately 7. From the analysis the City of

22 City of Gold Hill Biosolid Management Plan March 18, 2002 Page 5 of9 Gold Hill needs approximately nine acres to land apply on to handle their annual biosolid nitrogen production. IV Biosolid Beneficial Reuse Program Transportation and Land Application: Biosolids are off loaded into city-owned (1500gal.) tanker truck at the Biosolids Management Facility. The biosolid loading area is contained (surface drainage) in case of accidental spillage of biosolids during the truck loading process, This area surface drain ties back into the facility headworks. During the summer months Gold Hill's biosolids are land applied on a variable number of acres, depending on seasonal production from the facility. For the year 2001, Gold Hill land applied to two DEQ authorized sites totaling approx. 38-acres, The biosolid land application sites are capable of assimilating Gold Hill 's annual total nitrogen production. The perennial agronomic biosolid land application rate for pastures and grass is 100 lb. available N per acre-yr. The agronomic land application rate for annual ryegrass, the predominate crop utilized by Gold Hill's land application program, is 100 lb. available N per acre-yr. Land application: The City of Gold Hill land applies on privately owned farmlands. All DEQ site authorizations for the City are part of the City of Gold Hill's Biosolid Management Plan. The City has approx. 38 acres of farmlands to beneficially reuse their biosolids.