NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT Fact Sheet/Permit Evaluation Report

Transcription

1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT Fact Sheet/Permit Evaluation Report Oregon Department of Environmental Quality 2020 SW Fourth Avenue, Suite 400 Portland, Oregon FAX P. O. Box 68 Forest Grove, OR Plant Location: Scoggins Valley Road Gaston, Oregon Sources Covered: Log pond discharge (outfall 001) Land application of process wastewater solids (outfall 002) Source Category: Minor Industrial File Information: WQ-Washington County File No EPA Reference No.: OR Receiving Stream: Scoggins Creek Proposed Action: Issuance of renewal permit Source Contact: Steven Petrin Environmental Manager (503) Prepared by: Raj Kapur Northwest Region - Water Quality Program Date Prepared: April 2004 Updated: June 2004

2 1.0 Description of Proposed Action A National Pollutant Discharge Elimination System (NPDES) permit was issued by the Department of Environmental Quality (Department) to (Stimson) on April 25, 1997 (1997 NPDES permit). The 1997 NPDES permit authorizes Stimson to discharge log pond overflow to Scoggins Creek from November to April of each year. The permit expired on March 31, Stimson submitted a NPDES permit renewal application on October 1, Supplemental information was submitted by Stimson in March and April Along with the permit renewal application, Stimson requested that the renewed NPDES permit allow for a longer discharge period into the spring and early summer, when stream flows are higher in Scoggins Creek. Since a timely renewal application was submitted, Stimson has continued to operate under the terms and conditions of the 1997 NPDES permit. The Department is now proposing to renew the NPDES permit for Stimson. The Federal Water Pollution Control Act of 1972 and subsequent amendments require a NPDES permit for the discharge of wastewater to surface waters. Furthermore, Oregon Revised Statutes (ORS 468B.050) also requires a permit for the discharge of wastewater to surface waters. This proposed permit action by the Department fulfills both federal and state requirements. 2.0 Facility Description 2.1 General Stimson operates a sawmill and hardboard manufacturing facility. Products include commodity hardboard, exterior trim stock, siding face laminate, studs and dimensional lumber. The facility is located on Scoggins Valley Road near Gaston, Oregon. A site location map is presented in Figure 1. i >. ( m r «y '. '. l, ' i 1 "# 'v:r...: im -;l Log Pond ^.*, - ; X'J i" v.. Jl n \. * ' V" <* 1 if', i." -.,] <.. r -, M'ti;' '. \ _ Ki ii'lfi -. ^ i, ' m ".! ' OJ Figure 1 - Site Location Map 2»' - ^»

3 2.2 Wastewater Sources The primary source of water used within the mill is obtained from Scoggins Creek although tap water is also used for certain activities. The facility has three distinct activities: sawmill, hardboard plant, and powerhouse. Water flow diagrams for each of these activities are attached to this report. At the sawmill, small quantities of condensate (approximately 11 gallons per minute (gpm)) are discharged to the powerhouse feed water. Wash water from an equipment washing area is treated through a closed loop treatment system; however, there is potential for overflow from this location to enter the log pond. Thus, the washwater is listed as a source of wastewater to the log pond. However, the expected rate is small (less than 1 gpm). Wash down from the barkers is a significant source of wastewater entering the log pond (100 gpm). At the hardboard plant, wastewater is collected and is biologically treated and reused. Waste solids from the biological treatment process are stored in holding ponds and land applied/irrigated onto property owned by Stimson. Land application/irrigation occurs on a year-around basis. At the powerhouse, non-contact cooling waters are directed to the fire water pond for reuse. Other waste streams including boiler blowdown are discharged to the log pond. Storm water runoff from this portion of the facility is also directed to the log pond. Stimson also discharges storm water to Scoggins Creek through a drainage ditch on the southeastern portion of the facility. This storm water discharge is covered by DEQ's general storm water permit for industrial sources (# 1200-Z). 3.0 Water Quality Issues 3.1 Applicable Water Quality Standards The applicable water quality standards are found in Oregon Administrative Rule (OAR) They are intended to be protective of the beneficial uses for the basin, which include domestic water supply, industrial water supply, irrigation, livestock watering, anadromous fish passage, resident fish and aquatic life, salmonid spawning and rearing, wildlife, hunting, fishing, boating, water contact recreation, aesthetic quality, and commercial navigation and transportation. Scoggins Creek is a tributary of the Tualatin River, which is located in the Willamette River basin. The Tualatin TMDL states that the portion of Scoggins Creek below Scoggins Dam is considered spawning habitat for cut-throat trout, coho salmon, and steelhead. The fish use designations were developed by Oregon Department of Fish and Wildlife (ODFW). These designations have been adopted by DEQ in OAR , Figure 340B. The fish use designation map specifies that the spawning period for Scoggins Creek is from October 15 to May 15. However, recent fisheries studies in the area (Tualatin Basin Water Supply Feasibility Study, February 2004) did not find evidence of salmonid spawning near the Stimson facility. Scoggins Creek upstream and downstream of the Stimson facility was subjectively rated as "poor to fair" in habitat conditions for salmonids. The Department will work with the ODFW District Biologist to determine whether the fish use designation for Scoggins Creek should be revised. If the fish use designation for Scoggins Creek is revised by ODFW, water quality analysis will be conducted using the revised fish use designation. Selected water quality standards for the Scoggins Creek are presented in Table 1. Note that both the salmonid spawning criteria and the cold water aquatic life criteria for dissolved oxygen is presented.

4 TABLE 1: SELECTED SCOGGINS CREEK WATER QUALITY CRITERIA Parameter Dissolved Oxygen (OAR ) (October 15-June 30) Temperature (OAR ) PH (OAR ) Turbidity (OAR ) Total Dissolved Solids (OAR ) In-stream Water Quality Criteria Salmonid Spawning Criteria Not less than > 11.0 mg/l. However, if the minimum inter-gravel dissolved oxygen is 8.0 mg/l or greater, then the DO criterion is 9.0 mg/l. Furthermore, where conditions of barometric pressure, altitude, and temperature preclude attainment of the 11.0 mg/l or 9.0 mg/l criteria, dissolved oxygen levels must not be less than 95 percent of saturation. Cold Water Aquatic Life Criteria The dissolved oxygen may not be less than 8.0 mg/l as an absolute minimum. The 7-day average maximum temperature of a stream identified as having salmon and steelhead spawning may not exceed 13 C (55.4 F) > 6.5 and < 8.5 No more than a ten percent cumulative increase in natural stream turbidities shall be allowed, as measured relative to a control point immediately upstream of the turbidity causing activity. The concentrations listed below may not be exceeded unless otherwise specifically authorized by DEQ: 100 mg/l 3.2 Water Quality Criteria for Toxic Substances Table 20 of OAR specifies water quality criteria for toxic pollutants. Both criteria for protection of aquatic life and human health are presented in Table 20. Selected aquatic life and human health criteria are presented in Tables 2 and 3. The aquatic life criteria for several metals are based on hardness. For Scoggins Creek, a hardness of 25 mg/l was used to calculate aquatic life criteria for hardness dependent metals. This is a typical hardness for Willamette River basin streams. Aquatic life criteria for selected toxic pollutants are given below: TABLE 2: AQUATIC LIFE CRITERIA FOR TOXIC SUBSTANCES Parameter Unit Criteria for Protection of Freshwater Aquatic Life Acute Chronic Arsenic III MQ/L Cadmium MQ/L a 0.9 a 0.41 Copper MQ/L a 5.16 a 3.86 Iron MQ/L 1000 Lead MQ/L a a 0.61 Mercury MQ/L Nickel MQ/L a 469 a 52 Zinc MQ/L a 38.6 a a Hardness dependent criteria. A hardness of 25 mg/l was used. Human health criteria for selected toxic pollutants are given below:

5 TABLE 3: HUMAN HEALTH CRITERIA FOR TOXIC SUBSTANCES Parameter Criteria for Protection of Human Health Water & Fish Ingestion Fish Consumption only Drinking Water MCL* Arsenic III 2.2 ng/l 17.5 ng/l 0.05 mg/l Cadmium 10 MQ/L 0.01 mg/l Iron 0.3 mg/l Lead 50 ug/l 0.05 mg/l Mercury 144 ng/l 146 ng/l mg/l Nickel 13.4 ug/l 100 ug/l Selenium 10 MQ/L *MCL - Maximum Contaminant Level 0.01 mg/l 3.3 Tualatin River TMDL Section 303(d) of the Clean Water Act requires each state to develop a list of water bodies that do not meet state surface water quality standards after implementation of technology-based controls. The state is then required to complete a Total Maximum Daily Load (TMDL) program for water bodies on the 303(d) list. The TMDL program must address water quality on a basin-wide scale to ensure that overall water quality standards will be met. The Clean Water Act prohibits new or increased discharges until a TMDL has been established for 303(d) water bodies, unless the discharge does not contribute pollutants that cause the stream to violate water quality standards. In the late 1980's, the Department established TMDLs for ammonia and phosphorus in the mainstem Tualatin River to address dissolved oxygen, nutrient, chlorophyll a, and ph concerns. In August 2001, an updated TMDL for the Tualatin River was published. The 2001 TMDL addressed temperature, bacteria, phosphorus, ammonia, and volatile solids. Because NPDES Permit for Stimson authorizes discharge from November to April of each year, the Tualatin TMDL did not include wasteload allocations for Stimson. The TMDL did include a discussion of dissolved oxygen issues in Scoggins Creek. The TMDL stated that the portion of Scoggins Creek below Scoggins Dam does not meet the dissolved oxygen criteria from November 1 - April 30. The TMDL attributed the dissolved oxygen violations primarily to the releases from Scoggins Dam. However, the TMDL also states that the discharges from the Stimson mill most likely contribute to the dissolved oxygen violations in Scoggins Creek. As part of this permit renewal, the Department will further evaluate this issue. 3.4 Mixing Zones OAR provides that the Department may suspend all or part of the water quality standards in a designated portion of the receiving water to serve as a zone of dilution for wastes and receiving waters to mix thoroughly. Water quality standards for all parameters must be met at the edge of the defined mixing zone. Wastewater from the log pond is pumped to an "overflow" pond, which contains two pumps. The primary pump pumps wastewater from the "overflow" pond to Scoggins Creek through a 12-inch pipe that terminates at the edge of the stream. Stimson also has a secondary pump at the

6 "overflow" pond, which discharges wastewater on to the bank of Scoggins Creek. The width and the flow in Scoggins Creek are dependent on the release rate from Scoggins Dam. For the worst case scenario where the minimum release rate from the dam is 10 cubic feet/second and the velocity is 1 feet/second, the width of the stream is about 10 feet and the depth is about 1 feet. The 1997 NPDES permit specifies that the mixing zone for the discharge is that portion of Scoggins Creek 5 feet upstream and 100 feet downstream of the discharge. The permit does not allow discharge from May 1 - October 31 and allows discharge from November 1 - April 30 only when dilution in Scoggins Creek is at least 50:1. The Department will evaluate the mixing zone to ensure that it allows for passage and minimum dilution requirement to ensure that the discharge meets water quality standards Zone of Immediate Dilution A zone of immediate dilution (ZID) within the mixing zone is being proposed as allowed by OAR (2)(a)(A). Compliance with acute toxicity standards must be met at the edge of the ZID. The ZID is defined as that portion of Scoggins Creek 10 feet downstream of the discharge (i.e. 10% of the defined mixing zone). Dilution data are not available at the edge of the ZID. The Department will assume a 5:1 dilution at the edge of the ZID in evaluating compliance with acute water quality standards. 3.5 Antidegradation Review The Department's antidegradation policy in OAR requires that a review of discharges to surface waters be conducted to ensure that existing water quality is not lowered unless there are no reasonable alternatives available and the lowering of water quality is necessary for economic and social benefit. The NPDES permit for Stimson is a permit renewal with no increase in discharge load. Permit renewals with no increase in discharge load are not considered to lower water quality from existing water quality. Thus, the Department finds that the discharge is not subject to an in-depth antidegradation review. (Antidegradation Policy Implementation Internal Management Directive for NPDES Permits and Section 401 Water Quality Certifications, ODEQ March 2001). 4.0 Existing NPDES Permit Limitations The 1997 NPDES permit contained the following effluent limits: TABLE 4 EXISTING NPDES PERMIT LIMITS AT OUTFALL 001 Parameter Monthly Average Daily Maximum Oil & Grease Settleable Solids 10 mg/l 0.1 ml/l 15 mg/l 0.2 ml/l Floating Solids PH Shall not be detectable Shall not be outside the range of In addition to the above limits, the permit does not authorize discharge from May 1 to October 31 of each year. Discharge is allowed from November 1 to April 30 only when the dilution in Scoggins Creek is at least 50:1. Flow in Scoggins Creek is primarily controlled by releases from Scoggins Dam. During first portion of the wet season, a minimum flow of 10 cfs is maintained in Scoggins Creek as the reservoir is being filled. Flow rates are higher during the latter portion of the

7 year, when more flow is being released from the dam. Unless there is significant capacity in the log pond, Stimson typically needs to discharge at higher rates than allowed by the 50:1 dilution ratio in the 1997 NPDES permit. To create capacity in the log pond for early portion of the wet season, Stimson has requested a longer discharge period. Stimson believes that the longer discharge period (i.e. beyond April 30) will enable Stimson to lower the water level in the log pond and have capacity available for the following wet season. The permit also includes conditions for the land application of process wastewater. The 1997 NPDES permit states that all process wastewater shall be treated and recycled, or disposed of on land by irrigation. The secondary solids irrigation system shall be operated such that solids are contained on the irrigation site and runoff or ponding of wastewater does not occur. 5.0 Technology Based Limits Development of effluent limitations for the discharge from the Stimson facility involves first determining applicable technology based limits and then determining water quality based limits. The NPDES permit contains the more stringent of the technology based limits, water quality based limits or existing NPDES permit limits. EPA has developed technology-based standards called effluent limitation guidelines (ELGs) for many types of industries. The ELGs are typically expressed in terms of mass of a particular pollutant allowed per unit of production or unit of flow. ELGs are also expressed as concentration in which case the production is not relevant. If ELGs are not published for a particular industry, DEQ is required to follow federal guidelines and develop equivalent technology based guidelines. For existing point source discharges, ELGs have been developed for three categories: Best Practicable Control Technology Currently Available (BPT), Best Conventional Pollutant Control Technology (BCT), and Best Available Technology Economically Achievable (BAT). BPT represents the minimum technology level and applies to all existing point sources discharges for which ELGs have been published. BCT replaces BPT for conventional pollutants, and BAT replaces BPT for non-conventional and toxic pollutants. BPT limitations must be met upon publication of the ELGs. EPA allows additional time for facilities to comply with BCT and BAT limitations. Note, however, that all EPA deadlines for complying with technology based limits for promulgated ELGs have passed. Thus, a facility must be in compliance with applicable technology based limits. The applicable technology based standards for the Stimson facility are contained in 40 CFR Timber Products Processing Point Source Category. For this point source category, the term "process wastewater" specifically excludes non-contact cooling water, material storage yard runoff (either raw material or processed wood storage), and boiler blowdown. For dry process hardboard, veneer, finishing, particleboard, and sawmills and planing mills subcategories, fire control water is excluded from this definition. Within this category, the activities at the Stimson facility are subject to the following subparts: Subpart A - Barking Subcategory Subpart E - Wet Process Hardboard Subcategory Subpart I - Wet Storage Subcategory Subpart K - Sawmills and Planing Mills Subcategory The following is a summary of the requirements of each of these subcategories: Subpart A - Barking Subcategory: This subcategory prohibits discharge of process wastewater pollutants into navigable waters from mechanical barking installations. Stimson uses a mechanical 7

8 barker. The Department will include the prohibition against the discharge process wastewater from mechanical barking installations in the renewed NPDES permit. Subpart E - Wet Process Hardboard Subcategory: This subpart applies to discharges to surface waters from facilities which produce hardboard products using the wet matting process for forming the board mat. This subpart contains BPT effluent limits for BOD5, TSS and ph. BCT and BAT effluent limits have not been promulgated for this subpart. Since Stimson treats and recycles or land applies all wastewater from the wet process hardboard subpart, it is not subject to the production based effluent limits, which apply to facilities that discharge to surface waters. The permit will include a prohibition against the discharge of process wastewater from the hardboard manufacturing activities. Subpart I - Wet Storage Subcategory: This subpart applies to discharges to surface waters from the storage or unprocessed wood in log ponds and wet decks. BPT and BAT limits are both identical for this subpart and state that there shall be no debris discharged and the ph shall be within the range of The Department will include these limitations in the renewed NPDES permit. Subpart K - Sawmills and Planing Mills Subcategory: This subpart applies to discharges to surface waters from timber products processing procedures that include all or part of the following operations: bark removal (other than hydraulic barking), sawing, re-sawing, edging, trimming, planing and machining. BPT and BAT limits are both identical for this subpart and state that there shall be no discharge of process wastewater pollutants into navigable waters. As noted in Section 2.2, Stimson discharges condensate from the sawmill to surface waters but does not discharge process wastewater to surface waters. The Department will include a prohibition against the discharge of process wastewater from the sawmill in the renewed NPDES permit. 6.0 Water Quality Analysis This section determines pollutants of concern and evaluates each parameter to determine whether the concentration of the pollutant in the discharge represents a "reasonable potential to exceed" water quality standards. If the discharge concentration of a particular pollutant has a reasonable potential to exceed water quality standards, then water quality based effluent limits are established for that pollutant. The water quality analysis is based on the technology/existing limits, NPDES Permit application data, discharge characteristics, and the dilution within the ZID and mixing zone. 6.1 Pollutants of Concern Based on the review of the NPDES permit application, the Tualatin TMDL, and the supplemental information submitted by Stimson, the pollutants of concern associated with the discharge from the Stimson facility were determined. The primary pollutants of concern are BOD, dissolved oxygen, suspended/settleable solids, ph, and metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc). With the existing discharge, phosphorus is not pollutants of concern because Stimson discharges during the wet season and the TMDL for the Tualatin River applies during the dry season. With Stimson request to expand the discharge season into the spring and early summer when flows are higher in Scoggins Creek, the Department will determine whether phosphorus limits are appropriate. Analytical results for volatile/semi-volatile/base-neutral organic compounds and pesticides were below detection limits except for toluene. Toluene was reported as being present in the discharge at 54 u.g/l. Except for toluene, volatile/semi-volatile/base-neutral organic compounds and pesticides are not included as parameters of concern Dissolved Oxygen/Biochemical Oxygen Demand (BOD) BOD is a measure of the oxygen demand exerted by the organic matter in the wastewater. BOD can affect dissolved oxygen levels in the receiving stream. Dissolved oxygen analysis has both a 8

9 near-field component, which is primarily influenced by mixing, and a far-field component, which is primarily influenced by the oxygen demand exerted by the wastewater. Since the travel time to the edge of the mixing zone is quite short compared to the time required for the BOD to exert an oxygen demand, the near-field analysis is primarily influenced by dilution within the mixing zone. As discussed in Section 3.1, there is some debate regarding what dissolved oxygen criteria would apply to Scoggins Creek. The Department will work with ODFW to determine whether the current fish use designation for Scoggins Creek should be revised. Once a determination is made regarding the appropriate fish use designation for the stream, the Department will evaluate near-field dissolved oxygen impacts. A Streeter-Phelps dissolved oxygen analysis was conducted to determine the far-field effects on instream dissolved oxygen levels in Scoggins Creek and the Tualatin River as a result of the discharge from the Stimson facility. The analysis is presented as Attachment A. The results of the Streeter-Phelps dissolved oxygen analysis indicates that the primary impact of the discharge is at the point of discharge. The impact of the discharge on in-stream dissolved oxygen levels is muted at downstream locations ph As noted in Section 3.1, Applicable Water Quality Standards, the water quality standard for ph is The ph limit in the 1997 NPDES permit for outfall 001 is With the dilution available within the mixing zone, the discharge from the Stimson facility will be able to meet the water quality standard for ph at the edge of the mixing zone. Thus, a ph of is proposed for the discharge from outfall Suspended/Settleable Solids As noted in section 4.0, the Department applied a settleable solids limit in the 1997 permit as a means of controlling the discharge of solids from the facility. Stimson Lumber has been able to meet the settleable solids limit in its NPDES permit. Controlling suspended solids is a key aspect of improving overall effluent quality of the discharge from the log pond. However, there are no technology based limits or water quality standards for suspended solids. Therefore, the Department is proposing to continue using the settleable solids limit in the 1997 NPDES permit Total Dissolved Solids For Scoggins Creek, the applicable total dissolved solids water quality guidance level is 100 mg/l. Based on expected levels in the discharge ( mg/l) and with the available dilution in the mixing zone, the discharge is not expected to exceed the 100 mg/l at the edge of the mixing zone Temperature While there is some debate whether the Scoggins Creek below the dam supports spawning, the Tualatin TMDL identifies this portion of Scoggins Creek as spawning habitat for cut-throat trout, coho salmon, and steelhead. Based on OAR , Figure 340B, the spawning period for Scoggins Creek is from October 15 to May 15. OAR (4)(a) states that the 7-day average maximum temperature of a stream identified as having salmon and steelhead spawning may not exceed 13 C (55.4 F). Available data indicates that Scoggins Creek meets the applicable spawning criteria. OAR (1 l)(b) states that a point source that discharges to spawning waters that are colder than the spawning criterion, may not cause the water temperature in the spawning reach to increase more than the following amounts after complete mixing of the effluent with the river: (A) If the rolling 60 day average maximum ambient water temperature is 10 C to 12.8 C, the allowable increase is 0.5 Celsius above the 60 day average; or (B) If the rolling 60 day average maximum ambient water temperature, between the dates of spawning use as designated under subsection (4)(a) of this rule, is less than 10 9

10 degrees Celsius, the allowable increase is 1.0 Celsius above the 60 day average, unless the source provides analysis showing that a greater increase will not significantly impact the survival of salmon or steelhead eggs or the timing of salmon or steelhead fry emergence from the gravels in downstream spawning reach. Available data indicates that the 60 day average maximum ambient water temperature is between 10 C and 12.8 C during the discharge period (November to April). Thus, the Department will evaluate whether the discharge will cause more than a 0.5 C increase in stream temperature above the 60 day average. OAR (1 l)(b) states waters of the State that have summer seven-day-average maximum ambient temperatures that are colder than the biologically based criteria in section (4) of this rule, may not be warmed by more than 0.3 degrees Celsius (0.5 degrees Fahrenheit) above the colder water ambient temperature. This provision applies to all sources taken together at the point of maximum impact where salmon, steelhead or bull trout are present. Since the Department is restricting the discharge period to not include summer months, this provision does not apply. Using the minimum release rate from Scoggins Dam is 10 cfs and a stream temperature is 10.2 C, the effluent temperature was determined using a mass balance analysis for the 50:1 dilution scenarios. The calculation is as follows: T e =[(T mz *Q inz )-(Q s *T s )]/Q e Where: T e is the temperature in the effluent; Tmz is the temperature at the edge of the mixing zone based on an allowable increase of 0.5 C (10.7 C); Q mz is the dilution assuming complete mix (50); Q s is the portion of Scoggins Creek available for mixing (49); T s is the 60-day average temperature during the discharge period (10.2 C); and Q e is the effluent dilution factor when compared to the stream (1). The mass balance analysis indicates that the allowable discharge temperature assuming 50:1 dilution would be greater than 35 C. The discharge temperature is expected to be near ambient levels and well below the maximum allowable temperatures calculated above. Therefore, an effluent temperature limit is not proposed. Thermal Plume Criteria Recent revisions to the Department's water quality standards include temperature thermal plume limitations in OAR (d). This section of the rules contains criteria to prevent potential adverse impacts that may result from thermal plumes. The temperature thermal plume limitations that the Department has adopted are similar to the recommendations in the April 2003 EPA Region X Temperature guidance. The criteria as they apply to Stimson are discussed below: OAR (d)(A): Impairment of an active salmonid spawning area where spawning redds are located or likely to be located. This adverse effect is prevented or minimized by limiting potential fish exposure to temperatures of 13 degrees Celsius (55.4 Fahrenheit) or less for salmon and steelhead, and 9 degrees Celsius (48 degrees Fahrenheit) for bull trout. Stimson discharge: As noted in the analysis above, the discharge from the Stimson mill is not expected to increase stream temperature above 13 C (salmon and steelhead spawning). Scoggins Creek is not identified as bull trout habitat. 10

11 OAR (d)(b): Acute impairment or instantaneous lethality is prevented or minimized by limiting potential fish exposure to temperatures of 32 C or more to less than 2 seconds. Stimson discharge: The NPDES permit does not authorize Stimson to discharge during the summer period. When discharging effluent temperature are expected to be near ambient levels and are expected to be well below 32 C. OAR (d)(C): Thermal shock caused by a sudden increase in water temperature is prevented or minimized by limiting potential fish exposure to temperatures of 25 C or more to less than 5% of the cross-section of 100% of the 7Q10 flow of the waterbody. Stimson discharge: Since there is no discharge during the summer period and effluent temperature is not expected to be near 25 C, thermal shock impacts are not expected. OAR (d)(D): Unless ambient temperature is 21 C or greater, migration blockage is prevented or minimized by limiting potential fish exposure to temperatures of 21 C or more to less than 25% of the cross-section of 100% of the 7Q10 flow of the waterbody. Stimson discharge: When the Stimson mill is discharging, the expected temperatures in Scoggins Creek are well below 21 C. Furthermore, effluent temperatures are expected to be near ambient levels. Thus, the Department does not expect the discharge to cause a migration blockage. Thus, the analysis shows that the discharge from the Stimson mill meets the temperature thermal plume limitations in OAR (d) Toxic Pollutants Based on a review of the analytical data submitted with the NPDES permit application, the toxic pollutants of concern at outfall 001 are arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc. A water quality analysis was conducted to determine whether the levels of these pollutants in the discharge have a "reasonable potential to exceed" water quality standards. Table 5 specifies the aquatic life and human health water quality standards for each pollutant. Table 6 specifies the maximum effluent concentration of each pollutant of concern along with the number of samples collected, and the maximum probable effluent concentration based on a multiplier as discussed below. Appendix G of the Tualatin TMDL includes a discussion of the arsenic, iron and manganese issues in the Tualatin Basin. Based on extensive sampling conducted by Clean Water Services (formerly known as Unified Sewerage Agency of Washington County (USA)) in the Tualatin Basin, the median arsenic level was 3 u.g/l (based on 1140 samples). The Tualatin TMDL states the following: "Exceedances of arsenic, iron, and manganese standards were identified as being due to the natural geo-chemical environment and regional groundwater hydrology, and thus most likely reflect natural background conditions. These water quality standards will be re-evaluated in future triennial standards reviews." OAR (2) states the following: 11

12 Where a less stringent natural condition of a water of the State exceeds the numeric criteria set out in this Division, the natural condition supersedes the numeric criteria and becomes the standard for that water body. Arsenic data was also collected in Scoggins Creek just upstream of the Stimson mill. The median arsenic level at this location was also 3 (ig/l. Based on the conclusions in the Tualatin TMDL, the Scoggins Creek data, and the condition from OAR (2), the Department will use the median in-stream levels to evaluate the discharge from the Stimson mill. The maximum probable effluent concentration (refer to Table 6) is well above the median arsenic value for Scoggins Creek. The Department is proposing to use the median value in Scoggins Creek as the seasonal median for the discharge from the Stimson mill. TABLE 5 WATER QUALITY STANDARDS FOR TOXIC POLLUTANTS OF CONCERN Parameter Aquatic Life Criteria Human Health Criteria Drinking Water MCL Acute Criterion Chronic Criterion Water & Fish Ingestion Fish consumption only (Maximum Contaminant Level) Cadmium 0.9 ng/l a 0.41 ng/l a 10 MQ/L 0.01 mg/l Chromium 664 ng/l a 80 ng/l" 170 mg/l 3433 mg/l 0.05 mg/l Copper 5.16 ng/l a 3.86 ng/l a Lead 15.8 ng/l a 0.61 ng/l a 50 jg/l 0.05 mg/l Mercury 2.4 ng/l ng/l 144 ng/l 146 ng/l mg/l Nickel C 469ng/L a 52 ng/l a 13.4 MQ/L 100 MQ/L Toluene 17,500 ng/l 14.3 mg/l 424 mg/l Zinc 38.6 ng/l a 35 ng/l a a Hardness based criteria 12

13 TABLE 6 EFFLUENT DATA Parameter Maximum Effluent Concentration Number of Samples TSD Multiplier a Maximum Probable Effluent Concentration Arsenic 33.6 ug/l MQ/L Cadmium 0.50 ug/l ug/l Chromium 35.6 MQ/L MQ/L Copper 82.9 MQ/L MQ/L Lead 0.50 MQ/L ug/l Mercury 0.10 MQ/L MQ/L Nickel 98.4 MQ/L jg/l Toluene 54 MQ/L MQ/L Zinc 424 MQ/L MQ/L Multiplier that accounts for effluent variability from EPA's Technical Support Document for Water Quality Based Toxics Control When determining whether a discharge has the potential to exceed water quality standards, the Department accounts for the variability of the effluent. A multiplier is used to account for effluent variability in accordance with the methods outlined in EPA's Technical Support Document for Water Quality Based Toxics Control (March 1991). To determine whether the discharge has a reasonable potential to exceed water quality standards for these pollutants, a spreadsheet that simulates the approach in EPA's Technical Support Document for Water Quality Based Toxics was used. Maximum probable effluent concentrations (based on the multiplier), water quality criteria, and mixing zone dilution data are used to determine whether the discharge has a reasonable potential to exceed water quality standards. Attachment B contains the aquatic life criteria reasonable potential analysis and Attachment C contains the human health reasonable potential analysis. Because the human health standards for water & fish ingestion and the fish consumption only are either the same or more stringent than the drinking water MCLs, compliance with the water & fish ingestion and the fish consumption standards will ensure compliance with the drinking water MCLs. Thus, the human health standards evaluated compliance with the water & fish ingestion and the fish consumption criteria. Clean Water Services has collected some background data for metals available above the discharge location. While this data showed that metals levels above Stimson were mostly below detection limits, the data was collected during May - October and may not be representative of stream background levels during the time of the year when Stimson discharges. Therefore, background data was not used in the water quality analysis. The results of the aquatic life reasonable potential analysis indicate that the discharge has a potential to exceed aquatic life standards for copper, mercury and zinc. With respect to mercury, one sample was collected and it did not show detectable levels of mercury. Because only a single sample was collected and the analytical method used was above the aquatic life chronic criteria, the analysis indicated that the discharge had a reasonable potential to exceed water quality standards. The Department is proposing to include a monitoring requirement for mercury to determine 13

14 whether additional data collected confirms the results of the single sample. With respect to copper and zinc, the Department is proposing to include effluent limits based on protection of aquatic life in the NPDES permit. The human health reasonable potential analysis considered four pollutants (cadmium, mercury, nickel, and toluene). The results of the analysis indicate that the discharge does not have a reasonable potential to exceed human health standards for these pollutants. 7.0 Compliance History Stimson has had recent discharges of solids to Scoggins Creek as a result of irrigation equipment failure. The Department issued a Notice of Noncompliance on August 14, Stimson has replaced some of the irrigation equipment and has instituted more vigorous procedures to ensure that land application activities do not result in discharge to surface waters. On May 14, 2004, the Department issued a Notice of Noncompliance as a result of a site visit on April 30, The Notice of Noncompliance was issued for activities at the irrigation site which resulted in significant ponding of wastewater. Stimson has contested this determination, maintaining that ponding was due to precipitation; however, Stimson did not provide any data to support its position. With this renewal, the Department is requiring that Stimson Lumber conduct its irrigation practices at agronomic loading rates. 8.0 Discussion of NPDES Permit 8.1 NPDES Permit Outline The proposed NPDES permit is organized into a cover page and several schedules that are discussed further in this section. The schedules include: Schedule A - Waste Discharge Limitations Schedule B - Minimum Monitoring and Reporting Requirements Schedule C - Compliance Conditions and Schedules Schedule D - Special Conditions Schedule E - Not Applicable (this schedule is reserved for federal pretreatment requirements for publicly owned treatment works and is not applicable to this permit) Schedule F - General Conditions 8.2 Cover Page The cover page of the NPDES permit identifies that Stimson is permitted to discharge log pond water from its facility in accordance with the conditions and limitations of the permit. It identifies that Scoggins Creek is the receiving stream for the discharge. The permit also identifies that Stimson is authorized to land apply industrial wastewater and residual solids. 8.3 Schedule A - Waste Discharge Limitations At outfall 001, effluent limits are proposed for oil & grease, settleable solids, ph, arsenic, copper and zinc. The limits for oil & grease, settleable solids, and ph are the same as those in the 1997 NPDES permit. The effluent limits for the metals are based on the water quality analysis conducted as part of this permit renewal. The effluent limits at outfall 001 are presented in the table below: 14

15 Table 7: NPDES Permit Limits at Outfall 001 Parameter Oil & Grease Settleable Solids Monthly Average 10 mg/l 0.1 ml/l Daily Maximum 15 mg/l 0.2 ml/l Arsenic 3 ng/l (median during discharge season) Copper Zinc 21 ng/l 155 ng/l 37 ng/l 270 ng/l PH Must not be outside the range of Based on the available data at outfall 001, it appears that Stimson may not be able to consistently meet effluent limits for arsenic, copper and zinc. Therefore, the Department is proposing to issue a Mutual Agreement and Order (MAO) with the NPDES permit. The MAO includes a schedule for Stimson to conduct an alternatives evaluation and implement the selected alternative to meet the effluent limits specified in the NPDES permit. The far-field dissolved oxygen analysis indicates that the discharge does not cause a measurable reduction in dissolved oxygen levels. A near-field dissolved oxygen analysis was not conducted as part of this permit renewal. The Department will work with ODFW to determine whether the current fish use designation for Scoggins Creek should be revised. Once a determination is made regarding the appropriate fish use designation for Scoggins Creek, the Department will evaluate near-field dissolved oxygen effects. In addition to the effluent limits above, the Department is proposing to include the requirements from the technology based guidelines discussed in Section 5.0. The NPDES permit includes a prohibition against the discharge process wastewater from the mechanical barker, hardboard manufacturing activities, and the sawmill. The NPDES permit also includes a statement that there shall be no debris discharged from the log pond. For the land application program conducted at the facility, the Department is including provisions to ensure that the purpose of the land application program is for beneficial use of the wastewater and solids. To ensure this, the NPDES permit includes provisions that require that land application is conducted at agronomic loading rates such that soils, groundwater or surface waters are not contaminated. Schedule C of the NPDES permit requires the submittal of an industrial residuals management plan. The Department is proposing to continue to include the 50:1 minimum dilution requirement in the NPDES permit and the discharge period is from November 1 - April 30. Note, however, the permit includes a note indicating that the discharge period may be extended if unseasonably wet weather or other reasons beyond the permittee's control necessitate a discharge from the log pond from May 1-May 31. The NPDES permit specifies the mixing zone and ZID for outfall 001. The mixing zone defined in the proposed permit is similar to the one defined in the 1997 NPDES permit except that the Department had added a width component to clarify that the entire stream width is not available for mixing. A ZID was not included in the 1997 NPDES permit. The Department is proposing to add a ZID as allowed by OAR (2)(a)(A). For outfall 001, the mixing zone is defined as that portion of Scoggins Creek 5 feet upstream, 100 feet downstream, and not to exceed one-half 15

16 the width of the stream. The ZID is defined as that portion of Scoggins Creek 10 feet downstream of the discharge and not to exceed one-quarter the width of the stream. 8.4 Schedule B - Minimum Monitoring and Reporting Requirements Monitoring Requirements The parameters to be monitored and the monitoring frequencies are specified in the below. Table 8: Monitoring Requirements for Outfall 001 Parameter Flow Dissolved Oxygen BOD 5 TSS Settleable Solids Oil & Grease PH Turbidity Arsenic Cadmium Copper Lead Mercury Zinc Scoggins Creek Flow Minimum Dilution Minimum Frequency Daily 3/week 1/week 3/week 1/week 1/week 3/week 3/week 2/month 2/month 2/month 2/month 2/month 2/month Daily Daily Sample Type Measurement Measurement 24-hour composite 24-hour composite Grab Grab Grab 24-hour composite 24-hour composite 24-hour composite 24-hour composite 24-hour composite 24-hour composite 24-hour composite TVID Data Calculation The proposed monitoring frequency for flow, oil & grease, ph, Scoggins Creek flow and the minimum dilution calculation are the same as in the 1997 NPDES permit. The Department is proposing to reduce to the monitoring frequency of BOD and settleable solids. With respect to BOD, adequate data has been collected to characterize the discharge and the data suggests that the BOD levels in the discharge do not result in a reduction of in-stream dissolved oxygen levels. Regarding settleable solids, the data indicates that the facility has consistently complied with the effluent limits for this parameter. With the log pond and overflow pond in place, the Department expects that the settleable solids level in the discharge will continue to be below permit limits. Thus, the Department is proposing to reduce the monitoring frequency for settleable solids to once per week. Since the discharge to Scoggins Creek is dependent on the minimum dilution ratio and the facility may not be discharging each day, the NPDES permit includes a reduced monitoring requirement when the facility is not discharging each day of the week. 16

17 Monitoring is being proposed for turbidity and dissolved oxygen. As noted in the water quality analysis, dissolved oxygen is a parameter of concern and currently there is limited data regarding this parameter. Turbidity may be a parameter of concern and turbidity data from the log pond discharge has not been collected. The Department is also proposing monitoring requirements for metals of concern in the discharge (arsenic, copper, and zinc). The monitoring frequency is established at twice per month which is the basis of the effluent limits in Schedule A of the NPDES permit. The Department is also proposing a monitoring requirement for cadmium and lead. For these two pollutants, a single sample was collected. While the sample did not show detectable levels of cadmium and lead, these pollutants are typically found in storm water discharges and storm water is a component of the overall discharge from the facility. Other metals that are typically found in storm water (i.e. copper and zinc) showed an order of magnitude increase with increasing TSS levels. Cadmium and lead were analyzed when there was a low TSS level in the discharge and the data may not reflect the maximum effluent concentration in the discharge. The Department believes that as TSS levels increase, lead and cadmium levels in the discharge may increase similar to copper and zinc levels. Therefore, the Department is proposing to include a monitoring requirement for cadmium and lead. A sampling requirement for mercury is also being proposed as discussed in Section Reporting Requirements The proposed NPDES permit requires monitoring reports to be submitted on a monthly basis. Reports must be submitted to the Department by the 15 th of the month following the month. Because monitoring is required several times per week and the EPA monitoring form would not contain all the data, the permit requires Stimson to submit a spreadsheet that contains the necessary data. The EPA discharge monitoring form does not need to be submitted if Stimson includes all discharge data required by the permit, facility information, and certification/signature statement on the spreadsheet. This portion of the NPDES permit also specifies how "non-detect" sample results should be reported and requires that monitoring records be prepared in ink. 8.5 Schedule C - Compliance Conditions and Schedules The permit requires Stimson to submit an industrial residuals management plan within one year of permit issuance. This plan must include information regarding the current land application activities (i.e. area where land application occurs, how the wastewater/solids are land applied, application rate, characteristics of the material being land applied (i.e. percent solids, nutrient and metal levels), setbacks, application rate, groundwater and soils information, and monitoring program). The industrial residuals management plan must also include steps that Stimson will take to comply with permit requirements for land application activities (Schedule A.5) along with an implementation schedule. The permit also requires Stimson to submit an annual report that that summarizes industrial wastewater and solids management activities for the previous year. The permit also includes a schedule for Stimson to implement best management practices to control the discharge of solids to the log pond. As documented during the site visit on April 30, 2004, Stimson has not implemented management practices to effectively control the discharge of solids to the log pond. Within one month of permit issuance, the permit requires Stimson Lumber to submit a plan to control the discharge of solids to the log pond. With three months of Department approval, Stimson is required to implement the plan. 8.6 Schedule D - Special Conditions The following Special Conditions are included in Schedule D of the proposed NPDES permit. 17

18 A condition regarding the development of a contingency plan for preventing and handling spills. A condition stating that land application activities must be conducted for beneficial purposes and must be conducted in accordance with the Department approved industrial residuals management plan. Because housekeeping activities are an important aspect in determining effluent quality, the Department has included a provision that potential areas that may contribute pollutants to the log pond be kept clean. 8.7 Schedule F - General Conditions These conditions are standard to all NPDES permits and include language regarding operation and maintenance of facilities, monitoring and record keeping, and reporting requirements. 9.0 Next Steps 9.1 Public Comment Period The proposed NPDES permit will be made available for public comment. Public notice of the proposed permit will be mailed to parties on the Department's public notice mailing lists (WQ: PN (public notice) State, WQ: Washington County, and WQ: All Permits). 9.2 Public Hearing A public hearing will be scheduled to provide information and to seek comments. An information session will be provided at the beginning of the hearing with the opportunity for the public to ask any questions they may have about the permit. The Department will accept written or oral comment at the public hearing. 9.3 Response to Comments The Department will respond to comments received during the comment period. All those providing comment will receive a copy of the Department's response. Interested parties may also request a copy of the Department's response. Once comments are received and evaluated, the Department will decide whether to issue the permit as proposed or make changes to the permit or deny the permit. 9.4 Modifications to Fact Sheet and Permit Evaluation Report Depending on the nature of comment and any changes made to the permit as result of comment, this fact sheet and evaluation report may be modified. The Department may also choose to update the fact sheet and evaluation report through a memorandum responding to comments on the proposed NPDES permit Attachments Attachment A: Dissolved Oxygen Analysis Attachment B: Reasonable Potential Analysis for Protection of Aquatic Life Attachment C: Reasonable Potential Analysis for Protection of Human Health Attachment D: Effluent Limits for Protection of Aquatic Life 18