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

Transcription

1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT Fact Sheet and Permit Evaluation Report Oregon Department of Environmental Quality 2020 SW Fourth Avenue, Suite 400 Portland, Oregon FAX Permittees: City of St. Helens PO Box 278 St. Helens, OR and Plant Location: Municipal Sewage Treatment Plant 451 Plymouth Street St. Helens, OR Treatment System Class: IV Collection System Class: III Boise Cascade Corporation 1300 Kaster Road St. Helens, OR Sources Covered: Municipal Sewage Treatment Plant and Pulp and Paper Mill Process Treated Effluent - Kraft Pulp, Kraft Chemical Recovery, Bleach Plant, Paper & Pulp Production, Groundwood Production, Sanitary, Maintenance Activities, Start-ups, Shut-downs, and Malfunctions* Source Category: Major Municipal and Major Industrial City of St. Helens Contact: Greg Zielinski St. Helens Treatment Works Superintendent Preparers: Raj Kapur (503) Water Quality Source Control Section Northwest Region and Bleached Kraft Pulp and Paper Mill 1300 Kaster Road St. Helens, OR Receiving Streams: Columbia River and Multnomah Channel File Information: WQ-Columbia County File No EPA Reference No.: OR Proposed Action: Issuance of renewal permit and establishment of joint permittees Boise Corporation Contact: Joe Kovich Environmental Manager Date Prepared: June 20, 2003 Updated: July 23, 2003 * Discharges from these activities are allowed as long as they are amenable to treatment, routed to the plant's wastewater treatment system and effluent limitations are met.

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 the City of St. Helens on December 23, 1993 (1993 NPDES permit). The permit expired on December 31, Since a timely renewal application was submitted to the Department, the City of St. Helens has continued to operate under the terms and conditions of the 1993 NPDES permit pending Department action on the renewal application. As part of the permit renewal application, the City of St. Helens and the Boise Corporation (Boise) pulp and paper mill requested that they be made co-permittees and the permit be made a joint permit covering both the City's municipal sewage treatment works and Boise 's pulp and paper mill. The City and Boise believe that this arrangement better reflects and describes the relationship between them since With this permit action, the Department is proposing to make the City of St. Helens and Boise joint permittees. This is a significant departure from the previous permit, which was issued solely to the City of St. Helens. The Department believes this change creates a better situation for all parties, including the permittees, the Department, and the public, as described below. Pulp and Paper Mill Wastewater System For permitting purposes in the past, the wastewater treatment facility in question has been considered a municipal sewage treatment plant, or Publicly Owned Treatment Works (POTW). This description suggests a typical municipal sewage treatment plant that also provides treatment to the pulp mill's wastewater. However, in reality, it's the reverse: the facility is mainly a pulp mill wastewater treatment system that also provides treatment for municipal sewage. The municipal wastewater provides nutrients needed to the industrial waste stream that would otherwise be added. Of an average discharge of 30 million gallons per day, only about 1 million gallons is municipal wastewater; the remainder is pulp mill wastewater. The major part of the facility is the secondary treatment system, or Aerated Stabilization Basin (ASB). This large system was designed and sized to treat wastewater from the mill; it is far larger than anything required for treating the municipal wastewater alone. Since this facility is predominantly a pulp mill wastewater treatment facility, the Department is proposing to include Boise as a joint permittee in the proposed NPDES permit. Pretreatment Program As a POTW treating wastewater from a categorical industry, the City of St. Helens was required to develop and implement a pretreatment program. "Pretreatment program" refers to requirements and limits imposed on an industry that discharges to a POTW, with the ultimate purpose of ensuring that the industrial discharge does not overload or cause harm to the POTW's treatment process. In the normal situation, where a POTW treats primarily municipal wastewater with some industrial contribution, a pretreatment program with limits on the industrial discharges makes sense. However, as stated above, the facility in question is predominantly a pulp mill wastewater treatment system and it is appropriate to treat Boise as a direct discharger, subject to the regulations and limitations that a direct-discharging pulp mill would have to meet. The joint permit accomplishes this task. Regulatory Responsibilities In the past, the NPDES permit was issued only to the City of St. Helens. Enforcement actions by DEQ, EPA or the public were directed through the City of St. Helens, regardless of whether the compliance issue in question resulted from actions on the part of the City or the Boise pulp and paper mill. However, in 1998, Boise, the City and the Department entered into a Memorandum of Agreement (MOA that held Boise directly responsible for exceedances of the BOD, TSS and AOX limits of the City's NPDES permit. This proposed joint NPDES Permit continues Boise's primary responsibilities for these three pollutants and also makes Boise primarily responsible for exceedances of several other pollutants as

3 identified in the permit. Upon the issuance of the joint permit, the MOA is no longer needed and shall be terminated by the parties. Enforcement actions pertaining to other aspects of the Boise discharge had to be directed against the City, which then had to pass the enforcement action through to Boise as best they could. As a joint permittee with the City of St. Helens, Boise will now be directly accountable for any violations of applicable permit conditions or permit limits that it may cause. The Department believes that this change creates a better situation for all parties, including the permittees, the Department, and the public, and best reflects the design, operation, and the relationship of the two parties in managing the treatment system. The Federal Water Pollution Control Act of 1972 and subsequent amendments require an 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 The facility, comprising the existing City's wastewater treatment works and the adjacent Boise mill, is located along the west bank of Multnomah Channel in St. Helens as shown in Figure 1. \, i ;i. 7 ' r - *'""" ' 1 i -M N I l L t-; i * -i if, '"'"".,- /I' rt, - ^ ) ; ^ - ~ _ Puatt '.. ' S/t».' i- 1! t 11:1c-: / Outfall 001 # $tj I -U / \ S 'A'" if--- y i >,\" fr. pf\, '" Boise Cascade :i '-$y- \ r' P* a Paper Mill-,-"-> / f y f >f ',... - \yi-' ' /, V* < ', ' '. i I ' > 's/t-'-^. ) I ^. ": <\. '.' ' '.,.,*. * /,', / / t,., ii.,.\t -m _. > ' '' V!/ \>: i ''"'-7. ',.(i '.! i. I ' 'I "I," I'l <"!. <*"\ '«. Figure 1: Site Location A major portion of the City's wastewater treatment system is dedicated to the treatment of wastewater from the Boise mill. The combined facility is described below. Municipal sewage from St. Helens is collected in the City's sewerage system and transported to the treatment facility. St. Helens also receives municipal sewage from the City of Columbia City. The

4 collected municipal sewage flows first into a primary aerated treatment basin, and then into a chlorine contact chamber for disinfection. This partially treated municipal sewage then flows into the large Aerated Stabilization Basin (ASB) which provides secondary treatment. Wastewater from the Boise pulp and paper mill is collected within the mill and transported to a primary clarifier, where solids settle out and are removed. Effluent from the primary clarifier flows to a pump station and from there to the ASB for secondary treatment. The majority of flow into the ASB is from the mill, typically about 29 million gallons per day (MGD), whereas the municipal wastewater flow is typically about 1 MGD during dry weather. After secondary treatment in the ASB, the combined pulp mill and municipal wastewater is discharged via a diffuser to the Columbia River at River Mile St. Helens Municipal Sewerage System The City's sewerage system includes the treatment works as described above, and the collection system. The collection system consists of underground sewer pipes that receive wastewater from homes and businesses. Wastewater flows by gravity to the treatment works, or to pump stations, where it is pumped to the treatment works. During wet weather, rainwater leaks into the sewer pipes and increases the flow, sometimes exceeding the capacity of the system. When this occurs, excess mixed wastewater and rainwater can overflow from two locations directly into the Columbia River. These locations are labeled as Outfalls 008 and Boise Pulp and Paper Mill The Boise mill is a fully integrated facility that uses the bleached kraft pulping process to produce market pulp, tissue and fine papers. Production capacity is about 1,150 tons of air-dried pulp per day. This section discusses the process description and waste generation associated with pulping and finished product production at the mill. The manufacturing of paper products is carried out in two distinct phases: (1) the pulping of wood, and (2) the manufacture of paper. Pulping is the chemical and physical separation of fibers in wood and recovery of pulping chemicals. Boise uses the kraft process to produce pulp. Manufacturing of paper products consists of converting the pulp into the various grades of paper. Boise operates two continuous kraft digesters and three batch kraft digesters. The pulp from the kraft digesters is whitened in two bleach plants. The bleached kraft pulp is converted to paper on four (4) paper machines. The basic processes employed at the mill are briefly described below. Chip receiving and storage: Wood chips and/or sawdust are received by truck or railcar and are stored in large outdoor piles. Pulping process: Wood chips and/or sawdust are converted into pulp in a process called digestion. Wood chips and pulping chemicals called white liquor are mixed and heated in large pressurized vessels called digesters. Digestion dissolves the wood lignins that bind the wood fibers together. After digestion, the fiber, which is brown at this point, is separated from the dissolved lignins, spent pulping chemicals and undissolved chips or knots in a series of cleaning devices called knotters, deckers and brownstock washers. Chemical recovery processes: The mixture of spent pulping chemicals and lignins from the digestion process, known as black liquor, is processed to recover and recycle pulping chemicals and to produce energy. The black liquor, which initially contains a high percentage of water and is called weak black liquor, is first concentrated in a set of evaporators. Water is evaporated from the black liquor to produce heavy black liquor, which is approximately percent solids. Heavy black liquor is combustible, and is the primary fuel used in the recovery furnace. The heat from combustion of black liquor is used to

5 make steam for use in the mill, while the pulping chemicals form a molten sodium sulfate salt, called smelt, which collects in the bottom of the recovery furnace and flows into a smelt dissolving tank. The smelt solution is called green liquor. The green liquor is treated by the addition of quicklime (calcium oxide), which results in the formation of white liquor, which can be reused in the digestion process. A precipitate also forms, called lime mud; lime mud is heated in a lime kiln to convert it back to quicklime, which is then reused. Bleaching process: The washed pulp is bleached to whiten the pulp for production of white paper products such as office paper or tissue and towel products. Bleaching takes place in two bleach plants, each of which consists of several stages in which bleaching is done using chlorine dioxide, sodium hydroxide and/or hydrogen peroxide or mixtures of these. Formerly, chlorine and sodium hypochlorite were also used for bleaching, but use of these bleaching chemicals has been discontinued. Paper machines: The washed and bleached pulp is mixed with additional water and additives and then sent to paper machines for production of paper products. 3.0 Wastewater Sources and Outfalls Outfall 001: Combined Municipal and Kraft Mill Aerated Stabilization Basin Effluent This is the discharge line from the combined secondary treatment ASB into the Columbia River at River Mile Waste sources include all municipal wastewater sources and the bleached Kraft mill wastewaters, including process wastewaters, cooling waters, storm water runoff, and all other integrated process wastewaters resulting from operation and maintenance activities at the Boise pulp and paper mill. The combined average discharge flow is about 30 mgd. As noted above, approximately 95% of the total flow is from the Boise Mill. The secondary ASB is periodically dredged to remove solids. The secondary ASB was last dredged in fall 2002 and solids were disposed in a landfill. Solids are not typically removed from the primary basin which receives municipal wastewater as the basin is designed to allow solids carryover to the secondary ASB. Currently, solids from the Boise primary clarifier are managed as a solid waste and disposed of at Boise's permitted landfill in accordance with Solid Waste Permit No Outfall 001 discharges treated sanitary wastewater from the city sewerage system, and treated industrial wastewater from kraft pulp production, kraft chemical recovery, bleach plant, paper & pulp production, storm water, maintenance activities and other ancillary process activities. In addition to the normal wastewater discharge, Boise is authorized to discharge through outfall 001 wastewater associated with or resulting during essential maintenance, regularly scheduled maintenance, during startup and shutdown, spills and release (whether anticipated or unanticipated) from within the permitted facility, as long as they are amenable to treatment, routed to the plant's wastewater treatment system, and all effluent limitations are met. Outfall 002: Municipal Primary Treatment Facility Effluent This is an internal monitoring point for the discharge from the municipal primary treatment facility to the ASB. The monitoring location is at the discharge line from the chlorine contact tank into the ASB. Outfall 003: Influent to Municipal Primary Treatment Facility This is an internal monitoring point for the influent to the municipal primary treatment facility. The monitoring location is the discharge line from the municipal influent channel into the municipal primary treatment facility. Except for wastewater from the Boise pulp and paper mill, all domestic and industrial wastewater (including leachate from the Boise landfill) enter the municipal primary treatment facility at this location.

6 Outfall 004: Kraft Mill Primary Effluent This is an internal monitoring point for the discharge from the Boise primary treatment system into the combined secondary ASB. Waste sources include the combined bleach Kraft mill wastewaters, cooling waters, storm water runoff, and all other integrated process wastewaters resulting from operation and maintenance activities at the mill. Outfall 004 piping is owned and maintained by Boise. Outfall 005: Kraft Mill Bleach Plant Combined "A" Bleach Line This is an internal monitoring point for the hypothetical combined Boise "A" bleach line discharge, defined as representative samples from "A" bleach line acid (005 acid) and "A" bleach line caustic (005 caustic) sewers, and includes bleaching process filtrates and wastewaters generated at the mill. Outfall 006: Kraft Mill Bleach Plant Combined "B" Bleach Line This is an internal monitoring point for the hypothetical combined Boise "B" bleach line discharge, defined as representative samples from "B" bleach line acid (006 acid) and "B" bleach line caustic (006 caustic) sewers, and includes bleaching process filtrates and wastewaters generated at the mill. Outfall 007: Emergency Discharge from ASB This is the emergency discharge from the ASB to the Multnomah Channel at RM 0.2. Waste sources include all of the sources that are normally included in Outfall 001. Use of this outfall is restricted to emergency situations during periods of high Columbia River level when there is insufficient hydraulic head to discharge the entire secondary ASB effluent flow through the normal Outfall 001 diffuser. Outfall 008: Emergency Overflow of Sanitary Sewer Collection at Pump Station No. 1 This is an overflow from Sewage Pump Station No. 1 (MH 1A-25 on inlet line to the wet well) to a drainage way to the Columbia River. Outfall 009: Emergency Overflow of Pump Stations No. 2, No. 3, and Middle Trunk This is the discharge of a storm drain system that receives sanitary overflow from Pump Station No. 3 wet well, Pump Station No. 2 overflow at inlet manhole IF23, and overflow from the middle trunk at manhole Ml to a drainage way to the Columbia River. Outfall 010: Mill Intake Screen Return Water The mill draws water from Multnomah Channel for process use. The water intake includes a screen to screen out large debris. The debris is washed off the screen with river water and the debris and water are returned directly to Multnomah Channel at the intake point. 4.0 Water Quality Issues 4.1 Applicable Water Quality Standards The water quality standards for the North Coast - Lower Columbia Basin 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. Selected water quality standards for the Columbia River are presented in Table 1. The dissolved oxygen criteria are dependent on the fisheries habitat present in the river segment. The Columbia River at St. Helens is classified as a cold water fisheries habitat. TABLE 1: SELECTED COLUMBIA RIVER WATER QUALITY CRITERIA

7 Parameter Dissolved Oxygen Temperature PH Bacteria Turbidity Total Dissolved Solids In-stream Water Quality Criteria Cold Water Aquatic Life Criteria: > 8.0 mg/l (absolute minimum for surface samples) a No measurable increase (defined as 0.25 F at the edge of the mixing zone) in surface water temperature from anthropogenic activities is allowed when surface water temperature in the Columbia River exceed 68 F (20 C) > 6.5 and < 8.5 < 126 Escherichia coli (. coli)/100 ml (30-day log mean) based on a minimum of 5 samples; < 406. co//7100 ml (for any single test sample) 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. Guide concentrations of 500 mg/l for the Columbia River shall not be exceeded unless otherwise specifically authorized by DEQ a When the Department determines that adequate information exists, the dissolved oxygen shall not fall below 8.0 mg/l as a 30-day mean minimum, 6.5 mg/l as a seven-day minimum mean, and shall not fall below 6.0 mg/l as an absolute minimum. 4.2 Water Quality Criteria for Toxic Substances Table 20 of OAR specifies water quality criteria for toxic substances. The water quality criteria for several metals are based on hardness. The water quality criteria specified in OAR , Table 20 are based on a hardness of 100 mg/l. The water quality criteria were adjusted to reflect the actual hardness of the receiving stream. For the Columbia River, a hardness of 67 mg/l was used to calculate water quality criteria for hardness dependent metals. Water quality criteria for selected toxic constituents are given below:

8 TABLE 2: SELECTED WATER QUALITY CRITERIA FOR TOXICS Parameter Arsenic (trivalent) Cadmium Chlorine Copper Iron Lead Mercury Nickel Silver Zinc Unit Criteria for Protection of Freshwater Aquatic Life Acute 360 a a a a a 2.04 a 83.4 Chronic 190 a a a a a 75.5 a Hardness dependent criteria. A hardness of 67 mg/l was used for the Columbia River. This is based on water quality data collected by USGS at Warrendale, Oregon. Limited Columbia River data above St. Helens collected by EPA yields a hardness of (d) Listing Status 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. St. Helens/Boise (SH/BCC) facility discharges wastewater to the portion of the Columbia River that is listed as being water quality limited in the Department's (d) list of streams. Table 3 includes the parameters for which water quality standards in the Columbia River are not met and the season when standards are exceeded: Stream Segment Columbia River (Willamette River to Tenasillahe Island) TABLE 3: 303(D) LISTING INFORMATION Parameter Temperature Toxics - Arsenic Toxics - PCBs (tissue) Toxics - Pesticides (DDE in tissue) Season Summer Year-around Year-around Year-around Once a TMDL is completed, the parameter is no longer included in the 303(d) list. Since a TMDL was completed for 2,3,7,8-TCDD and total dissolved gas, these parameters are not included in the 303(d) list. Of the (d) listed pollutants, temperature is expected to be the primary pollutant of concern in the discharge from the SH/BCC facility. The discharge is not expected to contribute PCBs, pesticides (DDE), and arsenic at levels above background concentrations. A discussion of temperature issues is presented in the section titled "Water Quality Based Effluent limitations ". 4.4 Columbia River Flow Data Low flow in the Columbia River was estimated at St. Helens using the minimum release rates at the Bonneville Dam and 7Q10 low flows from major tributaries downstream of Bonneville Dam.

9 TABLE 4: ESTIMATED LOW FLOW OF THE COLUMBIA RIVER AT ST. HELENS Location Columbia River at Bonneville Dam Sandy River Willamette River Lewis River Columbia River at St. Helens Estimated Low Flow 82,000 cfs 273 cfs 5910 cfs 688 cfs -88,900 cfs 4.5 Mixing Zones OAR (4) 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. The mixing zone for Outfall 001 is defined as that portion of the Columbia River within a parallelogram 400 feet downstream of the diffuser and 100 feet upstream of the diffuser. Outfall 001 consists of a 48- inch diameter pipe with inch diameter ports directed perpendicular to the outfall. The ports are evenly spaced at 4-foot intervals from the end of the outfall. The nominal port depth is 15 feet at low water which typically occurs during summer, and 30 feet at high water which occurs during the spring. Assuming an effluent flow rate of 30 mgd which is distributed equally through the ports, the resulting effluent velocity is 8.4 feet/sec. A mixing zone study was conducted by Tetra Tech in The mixing zone study consisted of a field dye evaluation and computer modeling. The field dye study was conducted for several scenarios including current reversals. The mixing zone study report also consisted of various modeling runs. The field dye study and the computer modeling produced different results. Tetra Tech believed that the primary reason that the results of the field study did not match the dilution predicted by the computer modeling was because some of the outfall ports were not functioning properly (i.e., some of the ports were either covered with sediment or debris). The ports have since been cleaned. By adjusting the number of ports that are functional, the authors were able to match the model predictions to the field study. The closest predictions to field results were obtained assuming 9 of the 24 ports were open. A mixing zone dilution of 40 has been used in the discussions regarding mixing zone dilution factors. This dilution factor was based on averaging the results from the field studies and those from the computer modeling. The Department has used this dilution factor for the water quality analysis. The Department has reviewed and approved a dilution factor/mixing zone study plan submitted by the permittees in accordance with Department guidance. The permittees are required to complete the study and submit a final study report to the Department within twelve months of the permit issuance. As part of the study, the permittees are considering an extension of the outfall diffuser in order to improve effluent mixing in the receiving water. The proposed NPDES permit also specifies a mixing zone for outfall 007, the emergency discharge from the ASB. This mixing zone for outfall 007 is defined as that portion of the Multnomah Channel within a 100 foot radius of the discharge pipe. As noted above, use of this outfall is restricted to emergency situations during periods of high Columbia River level when there is insufficient hydraulic head to discharge the entire secondary ASB effluent flow through the normal Outfall 001 diffuser. A mixing zone for outfall 010 is specified in the proposed NPDES permit. Outfall 010 is the discharge from the Boise mill's raw water intake screens, which are continually flushed. The screens use

10 Multnomah Channel river water to flush debris back to the Multnomah Channel. This mixing zone for outfall 010 is defined as that portion of the Multnomah Channel within a 10-foot radius of the discharge Zone of Immediate Dilution A zone of immediate dilution (ZID) within the mixing zone has been established pursuant to OAR (4)(b)(A)(i). Compliance with acute toxicity standards must be met at the edge of the ZID. EPA guidance states that the ZID should be the most restrictive of the following criteria: 1) Within 10% of the distance from the edge of the outfall structure to the edge of the regulatory mixing zone. This would result in a ZID of 40 feet downstream and 10 feet upstream. 2) Within a distance of 50 times the discharge length scale in any spatial direction. The discharge length scale is the square root of the cross-sectional area of the port. In the case of a multi-port diffuser, this requirement must be met for each port using the appropriate discharge length scale of that port. This would result in a ZID of 24 feet. 3) Within 5 times the local water depth in any horizontal direction from any discharge outlet. This would result in a ZID of about 75 feet. The most stringent of the three criteria is 50 times the discharge length scale, which results in a ZID of 24 feet. The ZID is defined as an area within 24 feet in any direction from the diffuser. Computer modeling did not predict dilution at the edge of the ZID for this discharge. However, the 1992 mixing zone study did include measurements near the outfall. Since the acute standard is based on a short-term test (1-hour), the Department is proposing to use the lowest measurement (11) within the mixing zone as the ZID dilution. The Department does not believe that it is appropriate to use an average dilution to evaluate compliance with acute water quality standards because the acute criterion is a short-term test. For outfall 007, 10% of the defined mixing zone dimension is used to define the ZID in accordance with EPA guidance. This results in the ZID being defined as an area within 10 feet from the point of discharge. The Department believes that it is appropriate to use 10% of the mixing zone and not the other criteria because this is an emergency outfall that is rarely used and when it is used, it is during high flow conditions. 4.6 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 Department evaluated previous permitted levels and compared these values to technology-based effluent limits and has determined to use the lower of the two values for all pollutants in order to comply with Oregon's antidegradation policy. Therefore, the NPDES permit for St. Helens and Boise is a permit renewal with no increase in discharge load. Permit renewals with the same discharge load as the previous permit 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). 5.0 Existing NPDES Permit Limits The 1993 NPDES permit for the St. Helens/Boise facility (previously issued to St. Helens) includes the following effluent limits at outfall 001: 10

11 Parameter BOD5 TSS 2,3,7,8-TCCD AOX PH Table 5: Existing NPDES Permit Limits Daily Max Monthly Ave 19,600 Ib/day 12,800 Ib/day 50,057 Ib/day 26,862 Ib/day 0.57 mg/day (quarterly average) 0.40 mg/day (annual average) 2.6 kg/admt (monthly average) 1.5 kg/admt (annual average) Shall not be outside the range Fecal Coliform bacteria limits were specified for outfall 002, the discharge from the primary municipal treatment system into the secondary ASB. There was no bacteria limit at outfall Technology-Based Effluent Limitations Development of effluent limitations for the discharge from the St. Helens/Boise facility involves first determining applicable technology based limits that apply to pulp mill effluent, and then comparing with existing NPDES permit limits. The NPDES permit would include the more stringent of the existing NPDES permit limits, technology based limits or water quality 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 source 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. The applicable technology based standards for the Boise Mill are contained in 40 CFR Pulp, Paper, and Paperboard Point Source Category. Portions of these technology-based standards were updated by EPA in 1998 in a rulemaking effort called the Cluster Rule. Facilities were required to comply with the air pollution control requirements in the Cluster Rule by April 15, 2001 (3 years after publication), but the effluent limits do not become effective until the next renewal of the facility's NPDES permit. Upon issuance of this permit, Subpart B of 40 CFR 430 applies to the Boise facility. The production associated with each subcategory is presented in the below. Subpart Table 6: Applicable Technology Based Subpart & Production Levels Subpart B - Bleached Papergrade Kraft and Soda Description Market Pulp Tissue Fine Papers Production 284 ADT/day * 124 MDT/day** 622 MDT/day ** * Air Dry Tons per day, based on total pulp production of 1150 Unbleached Air Dry Tons per day ** Machine Dry Tons per day, based on total pulp production of 1150 Unbleached Air Dry Tons per day 11

12 Since Boise is an existing source, it is subject to the "best practicable control technology currently available" (BPT) effluent limits set forth in 40 CFR (a) for bleached kraft mills using a non-tcf bleaching process. Additionally, for non-conventional and toxic pollutants, the "best available technology economically achievable" (BAT) limits under 40 CFR (a) non-tcf also applies. Attachment A documents the calculations of the technology based effluent limitations. The following table presents the resulting technology based effluent limits based on the calculations in Attachment A. Since the ELGs specify an internal monitoring location for some parameters and the final effluent for others, the table below specifies the monitoring locations where the technology-based limit would apply. Table 7: Technology Based Effluent Limitations & Monitoring Locations Parameter BOD 5 TSS PH AOX Chloroform 2,3,7,8-TCDD 2,3,7,8-TCDF Trichlorosyringol 3,4,5-trichlorocatechol 3,4,6-trichlorocatechol 3,4,5-trichloroguaiacol 3,4,6-trichloroguaiacol 4,5,6-trichloroguaiacol 2,4,5-trichlorophenol 2,4,6-trichlorophenol Tetrachlorocatechol Tetrachloroguaiacol 2,3,4,6- Tetrachlorophenol Pentachlorophenol Daily Max 25,343 Ib/day 50,764 Ib/day Monthly Ave 13,173 Ib/day 27,313 Ib/day Within the range of at all times 2206 Ib/day 7.9 Ib/day <10pg/L 31.9 pg/l <2.5 pg/l <5.0 ug/l <5.0 ug/l <2.5 <2.5 <2.5 <2.5 <2.5 <5.0 ug/l <5.0 ug/l <2.5 <5.0 ug/l 1430 Ib/day 4.8 Ib/day *Boise has two bleach plants; the limitations apply at each bleach plant Monitoring Location Final Effluent (outfall 001) Final Effluent (outfall 001) Final Effluent (outfall 001) Final Effluent (outfall 001) While technology based limitations were not developed for chemical oxygen demand (COD), the ELGs include COD as a parameter of concern for which EPA may develop limits at a later date. Boise has monitored COD at outfall 001 on a daily basis since January 2000 and has provided the data to the Department. The data adequately characterizes COD levels in the wastewater discharge. Thus, the Department is not including monitoring requirements for COD in the proposed NPDES permit. Note that the TSS and BOD technology-based limitations in Table 7 do not include the municipal contributions from the City of St. Helens. If these contributions are also included, the TSS and BOD limits would be as follows: 12

13 Table 8: Combined Municipal and Industrial Technology Based Effluent Limitations Parameter BOD 5 (dry season) TSS (dry season) BOD 5 (wet season) TSS (wet season) Daily Max 25,593 Ib/day 51,014 Ib/day 26,093 Ib/day 51,514 Ib/day Monthly Ave 13,340 Ib/day 27,480 Ib/day 13,673 Ib/day 27,813 Ib/day The dry season BOD and TSS mass load limits were calculated using the basin standard of municipal treatment facilities of 20 mg/l and an average dry weather flow of 1 mgd. The wet weather mass load limits were calculated assuming 85% removal (30 mg/l BOD and TSS) and a flow of 2 mgd. 7.0 Comparison of 1993 Permit Limits and Technology-based Limits This section presents a comparison of the 1993 NPDES Permit limits with the technology-based limitations from EPA's effluent limitation guidelines. Since SH/BCC did not request a mass load increase, the proposed limits to be used for water quality analysis will be the more stringent of either the 1993 NPDES Permit limits or the technology-based limitations calculated above. For BOD and TSS, the 1993 NPDES Permit limits are more stringent than the limits calculated using the technology-based standards. Therefore, the 1993 NPDES permit limits will be used for the water quality analysis. For AOX, the effluent limitation guidelines are more stringent than the limits in the 1993 NPDES permit. Thus, the AOX limitation calculated in Section 6.0 will be used in the water quality analysis. The 1993 NPDES permit did not include limits for chloroform at the bleach plant. The technology based chloroform limits calculated in Section 6.0 will be used for the water quality evaluation. The 1993 NPDES permit included a wasteload allocation for 2,3,7,8-TCDD (dioxin) based on a 1990 TMDL for dioxin. The 1990 TMDL specified a wasteload allocation of 0.27 mg/l as a long-term average (LTA) dioxin limit based on exposure during a 70-year life span. According to USEPA guidance, the LTA should not be directly incorporated into permits as water quality based effluent limits. The water quality based limits depend not only on the waste load allocation, but also the monitoring frequency and anticipated variation in effluent quality at the discharge. Since permit compliance is based on shorter exposure durations, the LTA was converted to quarterly and annual limits based on the number of samples collected using statistics in EPA's Technical Support Document for Water Quality Based Toxics Control (March 1991). A LTA is converted to a shorter term limit using a coefficient of variation (0.6 in this case) and the number of samples collected. Based on quarterly sampling at outfall 001, the number of samples collected per quarter is one and the number of samples collected per year is 4. From Table 5-2, the respective multipliers are 2.1 and 1.5 for the 95 th percentile confidence interval. Using these multipliers along with the long-term average calculated in the TMDL results in the 0.57 mg/day quarterly average and 0.40 mg/day annual average. The bleach plant is the potential source for dioxin in the discharge and the technology-based limits specify a daily maximum value of <10 pg/l, which is applied at the bleach plant effluent. Based on bleach plant flow data from May through August, 2002 and assuming a bleach plant discharge concentration of 10 pg/l, which is equal to the effluent limit, the highest daily TCDD level in the discharge would have been 0.34 mg/day. This value is within the wasteload allocations in the NPDES permit. Recent sampling conducted by the National Council for Air and Stream Improvements (NCASI) has shown that dioxin concentration in the effluent (outfall 001) and in the ASB solids are below detection limits. Therefore, the Department believes that it is appropriate to use to the bleach plant effluent as a means of determining compliance with the TMDL allocations for dioxin. 13

14 Except for dioxin, the 1993 NPDES Permit did not include effluent limits for the other toxic organic pollutants listed in Table 7. Even though the technology-based limits for the chlorinated organic pollutants apply at the bleach plant effluent and will likely be diluted with wastewater from other sources, the Department, as a worst case condition, will evaluate these parameters further to determine whether more restrictive water quality based limits apply. The table below presents the more stringent limits between the 1993 NPDES permit limits and the technology based limits. These values will be used in the water quality evaluation in the next section. Table 9: Most Restrictive of 1993 NPDES Permit Limits and Technology-based Effluent Limits Parameter BOD 5 TSS PH AOX 2,3,7,8-TCDD Chloroform 2,3,7,8-TCDD 2,3,7,8-TCDF Trichlorosyringol 3,4,5-trichlorocatechol 3,4,6-trichlorocatechol 3,4,5-trichloroguaiacol 3,4,6-trichloroguaiacol 4,5,6-trichloroguaiacol 2,4,5-trichlorophenol 2,4,6-trichlorophenol Tetrachlorocatechol Tetrachloroguaiacol 2,3,4,6-Tetrachlorophenol Pentachlorophenol Daily Max 19,600 Ib/day 50,057 Ib/day Monthly Ave 12,800 Ib/day 26,862 Ib/day Within the range of at all times 2206 Ib/day 0.57 mg/day (quarterly average) 7.9 Ib/day <10pg/L 31.9 pg/l <2.5 pg/l <5.0 ug/l <5.0 ug/l <2.5 <2.5 <2.5 <2.5 <2.5 <5.0 ug/l <5.0 ug/l <2.5 <5.0 ug/l 1430 Ib/day 0.40 mg/day (annual average) 4.8 Ib/day *Boise has two bleach plants; the limitations apply at each bleach plant Monitoring Location Final Effluent (outfall 001) Final Effluent (outfall 001) Final Effluent (outfall 001) Final Effluent (outfall 001) Final Effluent (outfall 001) 8.0 Management Practices In addition to the technology-based limitations, EPA promulgated Best Management Practices (BMPs) for the Subpart B facilities (i.e. Bleached Papergrade Kraft and Soda). The BMPs are specified in 40 CFR The primary objective of the BMPs is to prevent leaks and spills of spent pulping liquors, soap, and turpentine. The secondary objective is to contain, collect, and recover at the immediate process area, or otherwise control, those leaks, spills, and intentional diversions of spent pulping liquor, soap, and turpentine that do occur. The Department is proposing to include the BMPs specified in 40 CFR in the NPDES permit. The technology-based standards require Boise to do the following: Develop and implement a BMP plan 14

15 Amend the BMP plan when there is a change in mill design, construction, operation, or maintenance that materially affects the potential for leak or spills of spent pulping liquor, soap, or turpentine from the immediate process area. The BMP Plan and any amendments must be reviewed by the senior technical manager at the mill and approved and signed by the mill manager. Maintain on its premises a complete copy of the BMP Plan and records specified in 40 CFR (g). Conduct a monitoring program for defining wastewater treatment system action levels that will trigger requirements to initiate investigations on BMP effectiveness and to take corrective action. Conduct daily monitoring of the influent to the wastewater treatment system to detect leaks and spills, track the effectiveness of the BMPs, and detecting trends in spent pulping liquor losses. Conduct an investigation or take corrective action when an action level is exceeded Submit results of daily monitoring activities, number and dates of exceedances of the action levels, and a description of the corrective actions taken to respond to the action level exceedances. The frequency for submitting these reports is not less than once per year. In addition to the effluent limits, the Department is proposing to include the bulleted items above in the NPDES permit. The technology-based standards include the following implementation schedule for the BMPs: Prepare BMP Plan and certify to DEQ that the BMP Plan has been prepared in accordance with the regulation by no later than April 15, 1999 (or on date of issuance of NPDES permit containing the requirement). Implement all BMPs that do not require construction of containment or diversion structures or the installation of monitoring and alarm systems by no later than April 15, 1999 (or on date of issuance of NPDES permit containing the requirement). Establish initial action levels by no later than April 15, 1999 (or on date of issuance of NPDES permit containing the requirement). Commence operation of any new or upgraded continuous, automatic monitoring systems that the mill deems to be necessary by no later than April 17, 2000 (or on date of issuance of NPDES permit containing the requirement). Complete construction and commence operation of any spent pulp liquor, collection, containment, diversion, or other facilities necessary to fully implement BMPs by no later than April 16, 2001 (or on date of issuance of NPDES permit containing the requirement). Establish revised action levels by no later than January 15, 2002 (or on date of issuance of NPDES permit containing the requirement). The Department will require Boise to provide a certification within thirty (30) days after permit issuance that the BMP requirements have been met. 9.0 Water Quality Analysis This section determines pollutants of concern and evaluates each pollutant 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 NPDES Permit application data, metals data from industrial pretreatment reports, discharge characteristics, Columbia River water quality data, and the mixing zone analysis referenced in Section 4.6, Mixing Zones. 15

16 9.1 Outfall Pollutants of Concern All pollutants for which technology-based limitations are established at outfall 001 are included as parameters of concern. Temperature is included as a parameter of concern because the discharge from the SH/BCC facility has a thermal component and because the Columbia River is listed on the 303(d) list as not meeting water quality standards for temperature. Dissolved oxygen is also included because the discharge has an oxygen demanding component. Although technology based limits are not included for turbidity, this is a pollutant of concern with pulp & paper mill effluents. Thus, it is being included as a pollutant of concern. The following parameters are also included in the discussion below: color, nutrients, and bacteria. As part of the industrial pretreatment program, the City has collected metals data. All metals monitored as part of the industrial pretreatment program are included as parameters of concern. In addition to the above-referenced parameters, the NPDES Permit application was reviewed to determine whether there are other pollutants present in the discharge which may have a reasonable potential to exceed water quality standards. Except for bis-2-ethylhexyl phthalate, analytical results for other semi-volatile and baseneutral organic compounds were below detection limits. Bis-2-ethylhexyl phthalate was present at mg/l. This pollutant is frequently detected in industrial and storm water discharges, however, the Department does not currently have water quality criteria for this pollutant. Thus, toxic organic pollutants other than those specified in the ELGs are not included as parameters of concern. Of the pollutants for which limitations are included in the ELGs, the only pollutants that may be present at detectable levels in the effluent are chloroform, AOX, and 2,3,7,8-TCDF; these pollutants are included as parameters of concern Dissolved Oxygen The 1993 NPDES Permit includes a BOD limit for the discharge from outfall 001. BOD is a measure of the oxygen demand exerted by the wastewater. BOD can affect dissolved oxygen levels in the receiving stream. Dissolved oxygen analysis has both a 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. A mass balance equation is used to determine the resulting dissolved oxygen levels at the edge of the mixing zone. The calculation is as follows: DO mz = (DO e * Qe + DO s * Q s ) / (Q mz ) Where: DO mz is the dissolved oxygen level at the edge of the mixing zone; DO e is the dissolved oxygen level in the effluent (0 mg/l); DO s is the dissolved oxygen level in the Columbia River upstream of the discharge (8.76 mg/l from Tetra Tech Study); and Q s is the portion of the Columbia River available for mixing (40) Q mz is the dilution at the edge of the mixing zone (41) Q e is the effluent flow as a ratio to river flow (1) The resulting DO levels at the edge of the mixing zone would be 8.54 mg/l, about 0.2 mg/l lower than upstream levels. A measurable reduction in dissolved oxygen levels is considered to be 0.1 mg/l. Thus, the near-field analysis indicates that the discharge has the potential to cause a measurable reduction in dissolved oxygen levels at the edge of the mixing zone (near-field). However, the discharge does not reduce dissolved oxygen levels below water quality standards. A Streeter-Phelps dissolved oxygen analysis was conducted by Tetra-Tech in 1992 to determine the farfield effects on in-stream dissolved oxygen levels in the Columbia River as a result of the discharge from 16

17 the SH/BCC facility. The Streeter-Phelps analysis predicted that the maximum oxygen deficit would be about mg/l. This analysis indicates that the discharge does not have a measurable effect on dissolved oxygen levels in the Columbia River. A more recent analysis was conducted by the Department as part of the NPDES permit renewal efforts for the SH/BCC facility (Attachment B). The analysis indicates that the maximum DO deficit occurs between 70 and 208 river miles downstream of the discharge location (note that the discharge is 86 miles from the Pacific Ocean) depending on stream velocities and the maximum DO deficit would range from mg/l to mg/l. In addition, this maximum impact is predicted to occur beyond the riverine environment of the Columbia River (where tidal dilution is substantial). The Department's dissolved oxygen analysis confirms that the discharge is not expected to cause a measurable change in far-field dissolved oxygen levels Turbidity The water quality standard for turbidity is dependent on background stream turbidity measurements. The standard states that no more than a 10% cumulative increase in stream turbidity levels is allowed relative to a control point immediately upstream of the turbidity causing activity. To establish permit limits and to determine compliance with this standard, it is necessary to conduct in-stream monitoring upstream of the discharge over a broad period time as well as to gather effluent discharge monitoring data for the same broad time period. Although the turbidity standard has existed for a number of years, it has historically (with limited exceptions) not been applied to point sources. Based on available effluent and stream turbidity data, and estimates for dilution within the mixing zone, it appears that the discharge from the SH/BCC facility may not be able to consistently meet the in-stream turbidity standard. However, additional information on stream turbidity levels immediately upstream of the discharge, including data representing seasonal variability, is necessary to implement the turbidity standard. Therefore, the Department will include a compliance schedule that requires SH/BCC to conduct a study which would characterize stream and effluent turbidity levels, mixing zone dilutions and improvements, and submit a report with proposed effluent turbidity limits. This compliance schedule also requires SH/BCC to conduct an evaluation of alternatives to reduce effluent turbidity levels and optimize diffuser design, and to implement selected alternatives to reduce impacts to water quality and to reduce effluent turbidity levels. It should also be noted that the Department is currently evaluating the water quality standard for turbidity to determine if it needs to be revised. The compliance schedule included in the NPDES permit will also enable consideration of any revisions to the water quality standard for turbidity Total Dissolved Solids For total dissolved solids (TDS), OAR specifies a guide concentration of 500 mg/l for the Columbia River. Background concentrations of TDS in the Columbia River are about 100 mg/l. Effluent TDS data is not available. The Department is proposing to include a monitoring requirement to characterize effluent TDS levels Temperature As noted in Section 4.1, Water Quality Standards, the temperature standard is defined as follows: "... unless specifically allowed under a Department-approved Surface Water Temperature Management Plan as required under OAR (3)(a)(D), no measurable temperature increase (defined as 0.25 F (0.14 C) at the edge of the mixing zone) resulting from anthropogenic activities is allowed...when surface water temperatures exceed F(20.0 C). " [OAR l-0205(2)(b)(A)] As noted above, this segment of the Columbia River does not meet water quality standards for temperature during the summer months. The discharge from the SH/BCC facility does have a thermal component and therefore, both effluent heat load/temperature limits and a temperature management plan 17

18 are required. To determine whether the discharge complies with "no measurable temperature increase" criteria in the temperature standard, a mass balance analysis was conducted. The calculation is as follows: T e =[(T mz *Q mz )-(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 (20.14 C); Q mz is the dilution at the edge of the mixing zone (41); Q s is the portion of the Columbia River available for mixing (40); T s in the water quality standard for the Columbia River (20 C); and Q e is the effluent dilution factor when compared to the stream (1). The mass balance analysis based on the available dilution within the mixing zone indicates that the allowable discharge temperature for the SH/BCC facility would be C. Based on the allowable effluent temperature, the excess heat load is calculated by subtracting the applicable water quality criterion from the discharge temperature. Excess heat loads were calculated using the following formula: H' = PC p Q(AT) 1000 \W \MW 10 6 W s J Where: H = Excess heat load (Megawatts (MW)) p = Density of water, (1.0 kg/l) C p = Specific heat of water, (4182 Joules/kg- C) Q = Discharge flow, ( max month flow 1.38 mvsec (31.58 mgd)) AT = Maximum allowable effluent temperature ( C daily max) minus applicable criterion (20 C) Based upon the formula above, the excess heat load for the SH/BCC discharge, given the mill's current maximum month flow, diffuser design and mixing zone dilution factor, would be 33.1 MW. : The discharge from the SH/BCC facility cannot reliably meet the "no measurable increase" standard and the excess heat load. Initially, the temperature issues at the SH/BCC facility were expected to be addressed as part of EPA's temperature TMDL for the Columbia River. However, EPA has delayed finalization of the TMDL for temperature for the Columbia River. Therefore, the Department is proposing to move ahead on the temperature issue and implement its temperature standard. Since the discharge from the SH/BCC facility cannot consistently meet the temperature standard, the permittees have requested a compliance schedule for meeting the temperature standard. The Department is proposing a compliance schedule that requires Boise to do the following: Finalize and submit a Water Quality Study Report within 6 months after permit issuance; the Water Quality Study Report will evaluate the effects of the discharge on water quality within the stream segment where SH/BCC discharges. Submit alternatives evaluations to evaluate mixing zone/dilution issues and to reduce effluent heat load within 12 months of permit issuance; If modifications to the outfall structure are proposed, Boise is required to submit plans and specifications for the project within 18 months after permit issuance; within two months after Department approval, the permittees will submit all applications and supporting materials to appropriate agencies to obtain permits/approvals; Implement selected "non-capital" preferred alternatives to reduce effluent heat load within 18 months of Department review and approval of preferred alternatives;

19 Implement selected "capital" preferred alternatives to reduce effluent heat load within 30 months of Department review and approval of preferred alternatives; Modifications to the outfall structure, if proposed, must be completed within 24 months after submittal of plans and specifications to the Department and permit approvals from appropriate agencies; Submit mixing zone/dilution study for the modified outfall structure, if constructed, within six months after completion of the outfall structure. Along with the mixing zone/dilution study, Boise will submit a request for revising the temperature and/or heat load limits to comply with applicable water quality standards or applicable TMDL for temperature. Based on anticipated time frames to conduct the studies, obtain necessary permits/approvals, and implement projects, it is expected that the compliance schedule will take about 54 months after permit issuance date to complete. In the interim, the Department is proposing to include an excess heat load limit based on current discharge conditions. In establishing the interim excess heat load limit, the Department considered the historical excess heat loads from the SH/BCC facility over the past five years. The Boise facility has made energyrelated improvements to its facility within the past five years that have provided for a reduction in the effluent flow, temperature, and excess heat load over this time period. The most significant of the mill projects was the recycling of process waters in the pulp mill screen room ("Screen Room Closed Cycle" project). This project occurred in 1998 and has made a measurable reduction to the calculated excess heat load. Based on historical data over the past five years and the improvements already made at the facility, the Department is proposing an interim excess heat load limit of 71.2 MW during the summer months when the receiving water temperature exceeds the standard. The permit requires the mill to review additional process improvement opportunities as well as improvements to the outfall diffuser among potential changes at the facility during the permit term in order to meet the temperature standard. TABLE 10: HISTORICAL MAXIMUM EXCESS HEAT LOADS DISCHARGED FROM SH/BCC FACILITY ( ) Year Maximum 7-Day Excess Heat Load (MW) ph As noted in Section 4.1, Applicable Water Quality Standards, the water quality standard for ph for this segment of the Columbia River is The ph limit in the 1993 NPDES permit is With the dilution available within the mixing zone, the discharge from the SH/BCC facility will be able to meet the water quality standard for ph. Thus, a ph of is proposed for the discharge Bacteria The 1993 NPDES permit included fecal coliform bacteria limits at outfall 002, an internal monitoring point for the discharge from the municipal primary treatment facility to the secondary ASB. Since the bacteria limits are water quality standards, it is more appropriate to apply them to the discharge from 19

20 outfall 001. Since 1993, the Department has replaced the fecal coliform bacteria standard with an E. coli standard. As noted in Section 4.1, Water Quality Standards, the bacteria standard is defined as follows: < 126 Escherichia coli (E. coli)l\00 ml (30-day log mean) based on a minimum of 5 samples; < 406 E. colil 100 ml (for any single test sample) Thus, the Department is proposing to include E. coli bacteria effluent limits at outfall Color Monitoring for color was required in the 1993 NPDES Permit. Recent color data (July April 2003) indicates an average color level in the effluent of 561 color units and a maximum of 823 color units. There is no numeric water quality standard for color. However, OAR (2)(k) prohibits "objectionable discoloration, scum, oily sleek, or floating solids, or coating of aquatic life with oil films." Using the maximum effluent level of 823 color units and the estimated dilution within the mixing zone, the resulting increase in color would be about 20 color units above background conditions at the edge of the mixing zone. Using the average effluent level of 561 color units and the estimated dilution within the mixing zone, the resulting increase in color would be about 14 color units above background conditions at the edge of the mixing zone. The increase in color levels in the river is further evidenced by the fact that the effluent plume is visible. However, since there is no numeric standard, it is difficult to establish an effluent limit for color. The Department believes that as the permittees address turbidity and temperature issues, through reduction projects and optimization of the diffuser design and effluent mixing, water quality impacts of color will be reduced. Since color is a parameter of concern with the discharge, the proposed permit continues to require periodic monitoring for color Nutrients Pulp and paper wastewaters are typically devoid of nutrients (nitrogen and phosphorus), which are necessary for the operation of biological treatment systems. Mills usually add a nutrient solution to the wastewater to promote biologic activity. In this case, the City's discharge provides a source of nutrients for the biological treatment system (ASB). The NPDES permit renewal application reports ammonia levels of 2.45 mg/l (maximum monthly average) and phosphorus levels of 1.28 mg/l (maximum weekly average) in the wastewater effluent. With the available dilution provided by the Columbia River, there would be no measurable increase in nutrient levels above background conditions in the Columbia River. Thus, effluent limits for nutrients are not proposed Toxic Pollutants Toxic pollutants of concern include metals, chloroform, AOX, and 2,3,7,8-TCDF. Chloroform, AOX, and 2,3,7,8-TCDF were analyzed further to determine if the proposed technology based limits are sufficient to protect water quality. The metals were analyzed to determine whether the levels in the discharge have a "reasonable potential to exceed" water quality standards. Note that 2,3,7,8-TCDD is not included as a toxic pollutant of concern in this analysis because a TMDL for this parameter has already been developed and wasteload allocations have been established. The following table specifies the water quality standards, if one has been adopted, for the metals, chloroform, AOX, and 2,3,7,8-TCDF. 20

21 Table 11: Toxic Pollutants of Concern at Outfall 001 Parameter Unit Acute Criterion Chronic Criterion Max Effluent Concentration AOX Technology Limit Chloroform 2,3,7,8-TCDF 28,900 1,240 Technology Limit Technology Limit Aluminum a b 1330 Arsenic (trivalent) b 3.66 Cadmium c 2.5 c 0.83 b 0.29 Copper c c 8.4 b 24 Cyanide b,d 5 Lead c 49.8 c 1.9 b 2.04 Mercury b,d Q1 Nickel c c b 9.36 Silver c b 0.12 Zinc c 83.4 " Based on proposed criteria b Based on outfall 001 data from Hardness based criteria Concentration specified is one-half the detection limit c 75.5 b 75.3 For AOX and 2,3,7,8-TCDF, there are no water quality standards that have been adopted by the Department. For these pollutants, the technology based limitations as calculated in Section 6.0 will be included in the NPDES permit. For chloroform, the estimated effluent concentration based on an average effluent flow rate of 30 mgd and the technology based mass limitations calculated in Section 6.0 is 0.03 mg/l, well below the acute and chronic water quality standards. Thus, the technology based limitations for chloroform would be protective of water quality. Metals data collected over a two-year period from January 2001 to December 2002 will be used in the reasonable potential analysis. While the City has data prior to 2001, the methods that were used for analysis were not as sensitive as those used during the last two years (i.e. the more recent data has lower detection limits). Therefore, the Department has used two years of data in the reasonable potential analysis. The maximum effluent concentration measured during this time period is presented in the table above. 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). Assuming that effluent quality follows a log-normal distribution with a coefficient of variation of 0.6, which is typical for environmental data, the applicable multiplier based on a total of 9 samples is 1.8 for the 95 th percentile confidence interval (Table 3-2, Technical Support Document for Water Quality Based Toxics Control). 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. Limited background data for metals are available above the discharge location (1977 data from EPA). Since this data is dated and detection limits are an 21

22 issue, the Department used data collected by Boise in 2000 as part of a water quality study in the vicinity of the discharge. The background concentrations that are used in the analysis are specified in Attachment C. Where data for a particular pollutant was not available, the background concentration was assumed to be zero. The results of the analysis are included in Attachment D. The results indicate that the discharge does not have a reasonable potential to exceed water quality standards. Thus, water quality based effluent limits are not proposed for metals Whole Effluent Toxicity Testing The 1993 NPDES Permit requires the City to conduct quarterly whole effluent toxicity (WET) testing of the discharge from outfall 001. Quarterly WET testing was conducted on the Pimephales promelas (fathead minnow) and the Ceriodaphnia dubia (water flea). An acute WET test is considered to show toxicity if the "No Observed Effect Concentration" (NOEC) occurs at dilutions greater than that which is found at the edge of the zone of immediate dilution (ZID). A chronic WET test is considered to show toxicity if "a significant difference in survival, growth or reproduction" occurs at dilutions greater than that which is known to occur at the edge of the mixing zone. Quarterly WET test results from 1999 to January 2003 were reviewed. From January 1999 to April 2002, the tests did not exhibit acute toxicity at 100% effluent and did not exhibit chronic toxicity at dilutions less than those that are known to occur at the edge of the mixing zone. However, the July 2002 and October 2002 were inconclusive with respect to chronic toxicity. The July 2002 and October 2002 test did not include a dilution that would be representative of the dilution at the edge of the mixing zone. Furthermore, subsequent evaluation of test results raised additional issues regarding the validity of the tests. The January 2003 test for the algae species was reported as anomalous and a follow-up test was conducted. The follow-up test did not exhibit chronic toxicity at dilutions less than those that are known to occur at the edge of the mixing zone. As a result of these tests, the Department asked that follow-up actions be taken and the permittees conducted monthly WET testing over a three month period (April - June 2003). The results of the accelerated WET testing program indicates that the discharge does not exhibit chronic toxicity at dilutions less than those that are known to occur at the edge of the mixing zone. In the proposed NPDES permit, the Department is proposing to continue maintaining the quarterly WET testing frequency. The Department is also requiring that SH/BCC conduct priority pollutant scans on a quarterly basis when WET testing is conducted. The priority pollutant scan along with the WET test data will be used to assess future WET test results Compliance History Files and Discharge Monitoring Reports were reviewed for the past 5 years. These indicate that the facility has had a good compliance record over this period. There have been two instances where the facility exceeded effluent limits during this period. In February 1999, the facility exceeded its daily maximum TSS limits. The exceedance occurred during solids dredging in the secondary ASB as a result of an equipment malfunction. In June 2000, the facility exceeded its daily maximum BOD limit as a result of an excursion at the Boise facility. Both these violations were temporary exceedances of permit limits and do not represent long-term compliance issues. As a result of infiltration and inflow into the City's collection system, the City experiences sanitary sewer overflows during wet weather. The permit prohibits dry season (May 22 - October 31) overflows except during exceptional storm events. The City has until January 1, 2010 to comply with the wet season overflow prohibitions. Schedule C of the permit requires the City to submit a plan and schedule which would enable them to comply with the wet season overflow prohibitions by January 1,

23 11.0 Discussion of NPDES Permit 11.1 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 - Pretreatment Schedule F - General Conditions 11.2 Cover Page The cover page of the NPDES permit identifies that St. Helens and Boise are permitted to discharge treated municipal and pulp mill wastewater in accordance with the conditions and limitations of the permit. Also listed in the cover page are the various internal monitoring points and emergency discharge outfalls. The permit also includes a note which authorizes discharges associated with or resulting from essential maintenance; regularly scheduled maintenance; startups and shutdowns; and spills and releases (whether anticipated or unanticipated) from within the permitted facility, as long as they are amenable to treatment, are routed to the plant's wastewater treatment system and effluent limitations are met Schedule A - Waste Discharge Limitations As discussed in previous sections, effluent limits are proposed at outfall 001 and the two bleach plants. The following table specifies the proposed effluent limits at outfall 001. Table 12: NPDES Permit Limits at Outfall 001 Parameter BOD5 TSS PH AOX 2,3,7,8-TCDD E. Coli Bacteria Daily Max 19,600 Ib/day 50,057 Ib/day Monthly Ave 12,800 Ib/day 26,862 Ib/day Within the range of at all times 2206 Ib/day 0.57 mg/day (quarterly max) 406/100 ml 1430 Ib/day 0.40 mg/day (annual average) 126/100 ml Excess Heat Load* 71.2 MW (7-day moving average of daily maximum excess heat load) Turbidity To be established upon completion of the turbidity study in Schedule C.3 * Interim limit that applies from June 1 - September 30. Final limit to be established upon completion of the temperature study in Schedule C.2 Since the discharge from the Boise Mill makes up about 95% of the flow and mass load, Boise has primary responsibility for compliance with all effluent limits in the Table above except for E.coli bacteria. The permit specifies joint responsibility for the bacteria limits since the City's sanitary sewage treatment plant is also a source of this pollutant. The effluent limits for BOD and TSS are the same as those limits in the 1993 NPDES permit; these limits are more restrictive than the corresponding technology based limits. The AOX limits and ph limits are based on EPA's Cluster Rule. The dioxin limits are based on 23

24 EPA's 1990 TMDL for dioxin. The 1993 NPDES permit included fecal coliform bacteria limits at outfall 002, an internal monitoring point for the discharge from the municipal primary treatment facility to the secondary ASB. Since the bacteria limits are water quality standards, it is more appropriate to apply them to the discharge from outfall 001. Since 1993, the Department has replaced the fecal coliform bacteria standard with an E. coli standard. Therefore, the Department is requiring that E.coli bacteria be monitored at outfall 001 in the draft permit. The draft NPDES permit includes a note that states that the facility will be deemed to be in compliance with the effluent limits for 2,3,7,8-TCDD at outfall 001 as long as the discharge from the bleach plants meets the technology based effluent limits. Since the effluent from the two bleach plant is the potential source of 2,3,7,8-TCDD, compliance with the technology based effluent limit at the bleach plant will ensure compliance with the TMDL WLA for 2,3,7,8-TCDD. As noted in Section 7.0, recent sampling conducted by NCASI has shown that dioxin concentration in the effluent (outfall 001) and in the ASB solids are below detection limits. Therefore, the Department believes that it is appropriate to use to the bleach plant effluent as a means of determining compliance with the TMDL allocations for dioxin. The draft NPDES permit includes an interim limit for excess heat load based on a review of historical excess heat loads for the most recent five years (see section 9.1.4). The heat load limits apply from June 1 - September 30. A final excess heat load limit will be established upon completion of the compliance schedule specified in Schedule C.2. The draft NPDES permit does not include effluent limits for turbidity until the studies as outlined in Schedule C.3 have been completed and the information necessary to implement the standard is gathered. The following table specifies the proposed limitations for each bleach plant effluent (outfalls 005 and 006). Outfall 005 is an internal monitoring point for the hypothetical combined Boise "A" bleach line discharge, defined as representative samples from A bleach line acid (005 acid) and A bleach line caustic (005 caustic) sewers, and includes bleaching process filtrates and wastewaters generated at the mill. Outfall 006 is also an internal monitoring point for the hypothetical combined Boise "B" bleach line discharge, defined as representative samples from B bleach line acid (006 acid) and B bleach line caustic (006 caustic) sewers, and includes bleaching process filtrates and wastewaters generated at the mill. Boise has primary responsibility for the discharge from these outfalls. 24

25 Table 13: Effluent Limits at the Bleach Plant (Outfalls 005 and 006) Parameter Chloroform 2,3,7,8-TCDD 2,3,7,8-TCDF Trichlorosyringol 3,4,5-trichlorocatechol 3,4,6-trichlorocatechol 3,4,5-trichloroguaiacol 3,4,6-trichloroguaiacol 4,5,6-trichloroguaiacol 2,4,5-trichlorophenol 2,4,6-trichlorophenol Tetrachlorocatechol Tetrachloroguaiacol 2,3,4,6-Tetrachlorophenol Pentachlorophenol Daily Max 7.9 Ib/day <10pg/L 31.9 pg/l <2.5 pg/l <5.0 ug/l <5.0 ug/l <2.5 <2.5 <2.5 <2.5 <2.5 <5.0 jg/l <5.0 jg/l <2.5 <5.0 jg/l Monthly Ave 4.8 Ib/day A recent revision to the Cluster Rule by EPA allows facilities to opt for a certification program in lieu of monitoring for chloroform at the bleach plants. If, after two years of weekly monitoring demonstrating compliance with the chloroform limits at the bleach plants, Boise decides to implement this alternative, it must notify the Department 90 days in advance of its intent to implement the compliance certification alternative as outlined in the rule (40 CFR (f)). The permit also identifies other outfalls and internal monitoring points. At each internal monitoring point or outfall, the party that has primary responsibility is identified. For example, outfall 002 is the discharge from the municipal primary treatment plant to the secondary ASB and the City has primary responsibility for the discharge from this location. At outfall 001 and outfall 007, the discharge from the secondary ASB, Boise is identified as having primary responsibility for the discharge from outfall 001. Even though outfall 001 is the combined municipal and pulp mill discharge, Boise is identified as having primary responsibility because their discharge comprises of about 95% of the flow to the secondary ASB. Outfalls 008 and 009 are emergency overflow points in the City of St. Helens collection system. The City has primary responsibility for the discharge from these locations. The permit includes language that prohibits dry season overflows except during certain storm events. The City has until January 1, 2010 to comply with the wet season overflow prohibitions. Schedule C of the permit requires the City to submit a plan and schedule which would enable them to comply with the wet season overflow prohibitions by January 1, Outfall 010 is the discharge of river water from the mill intake screen. The Boise water intake structure is located at the Multnomah Channel. The intake screens are continuously flushed with water from the Multnomah Channel and this outfall represents the return of the wash water discharged from the screens. Boise has primary responsibility for this discharge. The proposed NPDES permit includes an alternate method to determine compliance with the effluent limits for 2,3,7,8-TCDD at outfall 001. This method can be used by Boise to determine compliance with 2,3,7,8-TCDD limits at outfall 001 when 2,3,7,8-TCDD is measured at or above the Minimum Level of 25

26 10 pg/l at Outfalls 005 or 006 (the bleach plant effluent). Based on sampling conducted by NCASI in its report titled "Evaluation of sources of dioxin and dioxin-like compounds in bleached chemical pulp mill effluents and treatment plant residuals'''(may 2002), a 40% removal efficiency for 2,3,7,8-TCDD is being used for the ASB. The removal efficiency is based on data for octachlorodibenzo-p-dioxin (OCDD) congener. The proposed NPDES permit also specifies the mixing zone and ZID for outfall 001 and outfall 007. The mixing zone definition is the same as that in the 1993 NPDES permit. A ZID was not included in the 1993 NPDES permit. The Department is proposing to add a ZID as allowed by OAR (4)(b)(A)(i). For outfall 001, the mixing zone is defined as that portion of the Columbia River 400 feet downstream, 100 feet upstream and 100 feet off each end of the diffuser. The ZID is defined as that portion of the Columbia River within 24 feet in any direction from the diffuser. A mixing zone and ZID are also specified for outfall 007, the emergency discharge from the ASB. While this outfall has been in existence for some time and has been included in previous permits, it was omitted in the 1993 NPDES Permit. The Department is proposing to include this outfall and specify a 100 foot radius mixing zone and a 10 foot radius ZID. Similarly, the mill intake screen return water, outfall 010, has been in existence for some time, however, the discharge was not previously included in the NPDES permit. The Department is proposing to include a 10-foot radius mixing zone for outfall Schedule B - Minimum Monitoring and Reporting Requirements Monitoring Requirements The proposed NPDES Permit requires the reporting of the production data in the table below. Boise has primary responsibility for providing the data. Table 14: Reporting Requirement for Production Data Parameter Unbleached Pulp Production Bleached Kraft Market Pulp Bleached Kraft Fine Papers Bleached Kraft Tissue Units ADMT ADMT ADMT ADMT Minimum Frequency Monthly Monthly Monthly Monthly The monitoring frequencies and the parameters to be monitored at outfall 001 are specified in the table below. The City is primary responsibility for conducting the monitoring at outfall

27 Parameter Flow BOD 5 TSS PH AOX Temperature Turbidity E. coli bacteria Color NH 3 -N Total Dissolved Solids Table 15: Monitoring Requirements for Outfall 001 Whole Effluent Toxicity Priority Pollutant Scan Outfall condition Minimum Frequency Daily Daily Daily Daily Daily Daily Daily 2/week 1/week 1/quarter 1/quarter 2 nd and 4 th year Sample Type Continuous Recorder 24-hour composite 24-hour composite 24-hour composite Continuous Recorder 24-hour composite 24-hour composite 24-hour composite 24-hour composite 24-hour composite Visual Inspection The proposed monitoring frequency for flow, BOD, TSS, ph, ammonia and color are the same as in the 1993 NPDES permit. The Department is no longer requiring monitoring for carbonaceous BOD (CBOD) because BOD data is adequate to characterize the oxygen demanding component of the discharge. Daily monitoring is being proposed for AOX in accordance with the monitoring requirements specified in 40 CFR 430. As allowed by 63 FR dated April 15, 1998, the permit includes a note that allows the frequency of AOX monitoring to be reduced to once per week after completion of the five-year minimum monitoring requirement upon approval by the Department. Daily monitoring of effluent temperature using a continuous recording device is being proposed as recommended in the Department's guidance for temperature management plans. To characterize effluent turbidity levels, the Department is proposing that SH/BCC monitor the effluent for turbidity on a daily basis using composite sampling techniques. The 1993 NPDES permit required monitoring for total residual chlorine at the discharge from the City's primary treatment facility (outfall 002). With the detention time in the secondary ASB, chlorine levels are not expected to be of concern in the final discharge. This was recently confirmed by sampling conducted by the City that showed that the total residual chlorine levels in the discharge are less than 0.05 mg/l. The 1993 NPDES permit required bacteria monitoring at outfall 002. Since it is more relevant to determine whether the discharge from outfall 001 meets bacteria limits, the Department is proposing to require monitoring for bacteria at outfall 001. The Department is proposing once a month monitoring during the first year after permit issuance for total dissolved solids to characterize effluent TDS levels. Since recent WET tests have shown a potential effect on growth or reproduction at the lowest dilution tested, the Department is proposing to continue WET testing on a quarterly frequency. In addition, the Department is proposing that a priority pollutant scan be conducted on a quarterly basis along with the WET testing. For facilities that have industrial pretreatment programs, the Department requires monitoring for metals and cyanide. Since a requirement to conduct quarterly priority pollutant scans (which would include metals and cyanide) is being included in the proposed permit, the Department is not proposing to include separate requirements for metals and cyanide sampling. The permit does include a condition which 27

28 requires the City to ensure that the pretreatment pollutants of concern are included in the priority pollutant scan. The frequency for testing is the same as in the 1993 NPDES permit. For municipalities that have industrial pretreatment programs, the Department typically requires sampling based on three consecutive days of sampling. However, unlike conventional activated sludge sewage treatment plants, the day-today variability in the effluent quality is expected to be limited at the SH/BCC facility as a result of the long detention time in the ASB. Thus, the Department is proposing single day sampling instead of the three consecutive day sampling. From the temperature monitoring, the Department is proposing that the following data be provided. Table 16: Temperature Reporting Requirements for Outfall 001 Parameter Daily Maximum Temperature 7-day Average of Daily Maximum Excess Heat Load (Daily Maximum) Excess Heat Load (7-day Average of Daily Maximums) Minimum Frequency Daily Daily Daily Daily Sample Type Calculate Calculate Calculate Calculate The proposed NPDES permit also specifies monitoring requirements at internal monitoring points. At outfall 003, the influent to the municipal treatment facility, the monitoring requirements are as follows: Table 17: Monitoring Requirements for Outfall 003 Parameter Flow BOD 5 TSS PH NH 3 -N Metals (Ag, As, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Se, Zn) & Cyanide Minimum Frequency Daily 2/week 2/week Daily Quarterly Type of Sample Continuous Recorder 24-hour composite 24-hour composite 24-hour composite 24-hour composite The monitoring requirements at the influent to the municipal primary treatment plant are the same as in the 1993 NPDES permit. The monitoring for metals and cyanide is the result of required monitoring for municipalities that have industrial pretreatment programs. The City has primary responsibility for conducting the monitoring at outfall 003. In addition to technology based effluent limits, 40 CFR 430 specifies minimum monitoring requirements and sample types for parameters to be monitored at the two bleach plants. The following table specifies the proposed monitoring requirements at the bleach plant effluent and is taken directly from 40 CFR 430. Boise has primary responsibility for conducting the monitoring at the bleach plants.

29 Table 18: Monitoring Requirements at the Bleach Plant Effluent (Outfalls 005 and 006) Parameter Bleach Plant Flow Chloroform 2,3,7,8-TCDD 2,3,7,8-TCDF Trichlorosyringol 3,4,5-trichlorocatechol 3,4,6-trichlorocatechol 3,4,5-trichloroguaiacol 3,4,6-trichloroguaiacol 4,5,6-trichloroguaiacol 2,4,5-trichlorophenol 2,4,6-trichlorophenol Tetrachlorocatechol Tetrachloroguaiacol 2,3,4,6-Tetrachlorophenol Pentachlorophenol Minimum Frequency Daily 1/week Sample Type Calculation 24-hour composite For outfall 007, the emergency discharge from the ASB, the NPDES permit states that as a result of the proximity of this outfall location to outfall 001, monitoring conducted at outfall 001 will be considered to equivalent to monitoring at outfall 007 when it is being used. Except for estimating flow, separate monitoring at outfall 007 is not required. Using the flow estimate, the permit requires the calculation of the mass load of BOD, TSS and AOX. These mass loads would then be added to the mass loads calculated at outfall 001 to determine the total mass load discharged from the facility. The City has primary responsibility for conducting the monitoring at outfall 007. The parameters to be monitored and monitoring frequencies are specified in the table below. Table 19: Monitoring Requirements for Outfall 007 Parameter Flow BOD, TSS, and AOX Minimum Frequency Daily When Discharging Daily When Discharging Type of Sample Estimate Calculate Monitoring for flow is proposed at Outfalls 008 and 009, the overflows from the pump stations. The City has primary responsibility for conducting the monitoring. Continuous monitoring for temperature and turbidity levels upstream of the discharge is not feasible because of the difficulty in installing and securing a continuous recording device in this portion of the river. As part of the temperature and turbidity studies specified in Schedule C.2 and C.3, the permittees will gather data to establish background levels for turbidity and temperature Reporting Requirements The proposed NPDES permit requires monitoring reports to be submitted on a monthly basis. Monthly reports must be submitted by the 45th day following the end of the monitoring month. The laboratory turnaround time for some of the analytical test results is quite lengthy. Thus, the Department is allowing additional time for submitting the monthly reports. 29

30 This portion of the NPDES permit specifies how "non-detect" sample results should be reported; requires that monitoring records be prepared in ink; specifies the procedures for calculating the 7-day moving average; and defines continuous monitoring Schedule C - Compliance Conditions and Schedules This portion of the proposed NPDES Permit includes compliance conditions and schedules for providing a certification that the Best Management Practices specified in the EPA's technology standards have been met. Schedule C, Condition 2 includes a detailed schedule for addressing temperature issues. The elements and schedule for addressing temperature issues are presented in Section Schedule C, Condition 3 also includes a detailed schedule for addressing turbidity issues. The proposed permit requires the development of a turbidity study plan, implementation of the turbidity study plan, and submittal of the turbidity study results, which would include proposed turbidity limits. This condition also requires Boise to conduct a feasibility analysis to identify mechanisms to reduce effluent turbidity, implement selected mechanisms to reduce effluent turbidity, and improve outfall diffuser design and mixing. If the outfall structure is modified, the permit requires the submittal of a mixing zone/dilution evaluation, which would specify the applicable dilution factor(s). Boise is also required to submit a permit modification requesting the establishment of turbidity limits to comply with applicable water quality standards for turbidity. Schedule A of the permit includes language that prohibits dry season overflows except during certain storm events. It also includes a condition stating the City has until January 1, 2010 to comply with the wet season overflow prohibitions. Within six (6) months after permit issuance, Schedule C, Condition 4 requires the City to submit a report regarding whether the discharge from the emergency overflow outfalls (outfalls 008 and 009) meets the dry season criteria for overflow discharges to Waters of the State. The City is also required to submit an implementation plan and schedule for complying with wet season overflow requirements by January 1, Schedule D - Special Conditions The following Special Conditions are included in Schedule D of the proposed NPDES permit. This provision states that while both the City and Boise are jointly and severally responsible for the terms and conditions of the NPDES permit, the Department and the permittees recognize that each permittee has primary responsibility for certain limitations and conditions in the NPDES permit. For a violation of a condition that is designated the primary responsibility of one permittee as set forth in Schedule A or other condition of this permit, any resulting enforcement action will be directed against the permittee with primary responsibility. However, if the permittee assigned primary responsibility does not act or respond in a timely manner upon its assigned responsibility, then the Department may proceed against both permittees at its discretion. For a violation of a condition that is designated as joint responsibility, any resulting enforcement action by the Department will be directed against both permittees. The whole effluent toxicity testing procedures are specified in this portion of the NPDES Permit. This section specifies the organisms to be used in these tests; it also states that dual end-point test may be used in which acute and chronic end points can be determined from a single chronic test. This section also defines acute and chronic toxicity and specifies follow up actions to be taken if a whole effluent toxicity test shows toxicity. 30

31 The Department is proposing to include the requirements to implement best management practices as discussed in section 8.0. The permit requires Boise to: S Develop and implement a BMP plan S Amend the BMP plan when there is a change in mill design, construction, operation, or maintenance that materially affects the potential for leak or spills of spent pulping liquor, soap, or turpentine from the immediate process area. S Have the BMP Plan and any amendments be reviewed by the senior technical manager at the mill and approved and signed by the mill manager. S Maintain on its premises a complete copy of the BMP Plan and records specified in 40 CFR (g). S Conduct a monitoring program for defining wastewater treatment system action levels that will trigger requirements to initiate investigations on BMP effectiveness and to take corrective action. S Conduct daily monitoring of the influent to the wastewater treatment system to detect leaks and spills, track the effectiveness of the BMPs, and detect trends in spent pulping liquor losses. S Conduct an investigation or take corrective action when an action level is exceeded S Submit results of daily monitoring activities, number and dates of exceedances of the action levels, and a description of the corrective actions taken to respond to the action level exceedances. The frequency for submitting these reports is not less than once per year. Schedule D of the NPDES permit also includes conditions regarding re-opening of the NPDES permit to include Columbia River TMDL WLAs, a contingency plan for spills and unplanned discharges, designation of an environmental supervisor, implementation of a pollution prevention program, and flow measurement. The permit includes a condition regarding the management of solids. The permit notes that a management plan for the beneficial re-use of solids has not been submitted. It also states that Boise may beneficially re-use primary clarifier solids by submitting a sludge management plan to the Department for review and approval. Beneficial use alternatives could include direct land application, composting, or other options where the solids could be utilized as a raw material in a manufacturing process. The City's primary solids and the solids from the ASB are regulated under Oregon Administrative Rules (OAR) , which includes procedures for obtaining approval for beneficial reuse of the solids. Approval of beneficial reuse of solids from the City's primary treatment facility and the secondary ASB will a modification of the NPDES permit. Until such time as beneficial reuse is approved by the Department, solids from the City's primary treatment facility, Boise's primary treatment facility, and the secondary solids from the ASB must be disposed at a properly licensed and permitted solid waste disposal facility. The Department is also proposing to include in Schedule D conditions regarding the discharge of water from pressure relief valves, a statement regarding the use of this document in helping interpret and apply permit conditions, Operation and Maintenance Manual, Biocide Certification, default comment period, and the Memorandum of Agreement between the City, Boise and the Department referenced in Section Schedule E - Pretreatment Activities The City is proposing to maintain its industrial pretreatment program, which would apply to industrial discharges except the Boise Pulp and Paper Mill. The provisions contained in this section are standard conditions that are included in municipal permits where the municipality implements an industrial pretreatment program. The City has primary responsibility for implementing this program. These provisions require the City to develop legal authority (adopt a sewer use ordinance with pretreatment 31

32 provisions), update its industrial user survey, permit, inspect, sample, and if necessary, take enforcement action against an industrial user. This portion of the permit also requires the City to submit an annual pretreatment report which summarizes pretreatment activities for the previous calendar year by March 1 of each year 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 Threatened and Endangered Species Fisheries agencies were contacted during the permit drafting process to obtain information regarding: Spatial and time distribution of species; Life cycle characteristics of species; Presence of threatened and endangered species; Identification of important habitat; Species, type, abundance, seasonality, habitat, sensitivity; Water quality factors affecting a species; Factors that limit the abundance and diversity of species; and Identification of feeding areas, fish passage areas, spawning areas, aerating area, and resting area, if present, and their value to the biological community. The Department received replies from National Oceanic and Atmospheric Administration (NOAA) Fisheries (formerly called National Marine Fisheries Service), United States Fish and Wildlife Service (USFWS), and the Fish Passage Center - Columbia Basin Fishery Agencies and Tribes. The information provided by these sources confirmed the presence of listed threatened and endangered species in this portion of the Columbia River. These include Columbia River Chum Salmon, Lower Columbia River Chinook Salmon, Upper Columbia River Chinook Spring-run, Upper Willamette River Chinook Salmon, Snake River Chinook Fall-run, Snake River Chinook Spring/Summer-run, Upper Columbia River Steelhead, Snake River Basin Steelhead, Lower Columbia River Steelhead, Upper Willamette River Steelhead, Middle Columbia River Steelhead and the Snake River Sockeye. The Lower Columbia River Coho Salmon is a "candidate" species for listing under ESA. Federally listed bald eagles are also present in the immediate vicinity of St. Helens. Based on the time distribution of species provided by the agencies, listed species are expected to be present throughout the year. USFWS and the Fish Passage Center stated that the location where the SH/BCC facility discharges is an important area for Willamette, Snake, and Columbia River stocks of salmon. USFWS was concerned that the discharge has potential to move fish located in the area to less suitable areas where they are more prone to predation. USFWS suggested that moving the discharge location further out into the Columbia River may reduce the impact of the discharge on fishery resources. The temperature and turbidity conditions in Schedule C of the permit require SH/BCC to consider relocating the outfall. Schedule C of the permit includes a schedule for relocation of the outfall. USFWS suggested that efforts to reduce effluent temperature would be advantageous to fish and wildlife. The Department has included a requirement for Boise to evaluate alternatives to reduce effluent heat load. The permit requires Boise to implement preferred alternatives, which are reasonably available, and can be implemented to reduce effluent heat load and meet the Oregon WQ criteria of "no measurable increase" (0.25 F) at the edge of the mixing zone. 32