FACT SHEET FOR NPDES PERMIT WA000076-1 

TESORO REFINING & MARKETING LLC

May 2013

PURPOSE of this Fact Sheet

This fact sheet explains and documents the decisions Ecology made in drafting the proposed 

National Pollutant Discharge Elimination System (NPDES) permit for Tesoro RefiningAnacortes.

The Environmental Protection Agency (EPA) developed the NPDES permitting program as a 

tool to “restore and maintain the chemical, physical, and biological integrity of the Nation’s 

waters.” EPA delegated to Ecology the power and duty to write, issue, and enforce NPDES 

permits within Washington State. Both state and federal laws require any industrial facility to 

obtain a permit before discharging treated process water to a water body.

An NPDES permit limits the types and amounts of pollutants the facility may discharge. Those 

limits are based either on (1) the pollution control or wastewater treatment technology available 

to the industry, or on (2) the receiving water’s customary beneficial uses. This fact sheet 

complies with Section 173-220-060 of the Washington Administrative Code (WAC), which 

requires Ecology to prepare a draft permit and accompanying fact sheet for public evaluation 

before issuing an NPDES permit.

PUBLIC ROLE in the Permit 

Ecology makes the draft permit and fact sheet available for public review and comment at least 

thirty (30) days before issuing the final permit to the facility operator (WAC 173-220-050). 

Copies of the fact sheet and draft permit for Tesoro Refining-Anacortes, NPDES permit WA

000076-1, are available for public review and comment from May 29, 2013 until the close of 

business July 29, 2013. For more details on preparing and filing comments about these 

documents, please see Appendix A - Public Involvement.

Before publishing the draft NPDES permit, Tesoro Refining-Anacortes reviewed it for factual 

accuracy. Ecology corrected any errors or omissions about the facility’s location, product type 

or production rate, discharges or receiving water, or its history.

After the public comment period closes, Ecology will summarize substantive comments and our 

responses to them. Ecology will include our summary and responses to comments in this Fact 

Sheet as Appendix M - Response to Comments, and publish it when issuing the final NPDES 

permit. Ecology will not revise the rest of the fact sheet, but the full document will become part 

of the legal history contained in the facility’s permit file.

J. Mark Dirkx, P.E. prepared the permit and this fact sheet.
FACT SHEET FOR NPDES PERMIT WA000076-1 

SUMMARY

The Tesoro Refining-Anacortes operates a wastewater treatment plant that discharges to Fidalgo 

Bay. Ecology issued the previous permit for this facility on April 19, 2006.

The proposed permit contains effluent limits for the conventional pollutants Biochemical 

Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Oil 

and Grease (O&G), phenols, hexavalent chromium, ammonia, and sulfide similar to the previous 

permit.

Ecology retained limits at the biological treatment system to ensure that flow and BOD loading 

do not exceed approved facility design criteria. The proposed permit increases the monitoring 

frequencies from the previous permit for TSS, O&G, and, sulfide; reduces frequencies for

BOD5and COD; and retains the frequency for phenol, ammonia, and fecal coliform.

The proposed permit adds a new acute toxicity limit and increased acute and chronic toxicity 

sampling frequency and a herring toxicity study.
DRAFT NPDES FACTSHEET FOR PUBLIC NOTICE

5/22/2013

TABLE OF CONTENTS

I. INTRODUCTION.......................................................................................................................1

II. BACKGROUND INFORMATION............................................................................................2

A. Facility Description......................................................................................................3

Site Description and History....................................................................................3

Industrial Process.....................................................................................................3

Wastewater Treatment .............................................................................................4

Solid Wastes.............................................................................................................4

Discharge Outfalls ...................................................................................................4

B. Summary of Compliance with Previous Permit Issued ............................................5

C. Review of Previous Permit Requirements.................................................................6

D. Wastewater Characterization .....................................................................................7

E. Description of the Receiving Water............................................................................8

F. SEPA Compliance ........................................................................................................9

III. PROPOSED PERMIT CONDITIONS......................................................................................9

A. Design Criteria ...........................................................................................................10

B. Technology-Based Effluent Limits ...........................................................................11

Process Wastewater ...............................................................................................11

Ballast and Stormwater Allocations.......................................................................16

Final Effluent Discharge for Firewater Testing.....................................................18

Construction Stormwater ......................................................................................18

C. Surface Water Quality-Based Effluent Limits........................................................18

Numerical Criteria for the Protection of Aquatic Life...........................................18

Numerical Criteria for the Protection of Human Health........................................18

Narrative Criteria ...................................................................................................18

Antidegradation......................................................................................................19

Mixing Zones.........................................................................................................20

D. Designated Uses and Surface Water Quality Criteria............................................25

E. Evaluation of Surface Water Quality -Based Effluent Limits for Numeric 

Criteria..................................................................................................................26

F. Whole Effluent Toxicity.............................................................................................32

Pacific Herring.......................................................................................................33

G. Human Health............................................................................................................35

H. Sediment Quality........................................................................................................37

I. Ground Water Quality................................................................................................37

IV. MONITORING REQUIREMENTS........................................................................................38

A. Lab Accreditation ......................................................................................................39

B. Performance-Based Reduction of Monitoring Frequencies...................................39

V. OTHER PERMIT CONDITIONS ...........................................................................................40

A. Priority Pollutant Testing..........................................................................................40

B. Reporting and Recordkeeping ..................................................................................40

C. Operation and Maintenance Plan.............................................................................40
DRAFT NPDES FACTSHEET FOR PUBLIC NOTICE

5/22/2013

D. Non-Routine and Unanticipated Discharges...........................................................40

E. Wastewater Treatment Efficiency Study and Updated Engineering 

Report....................................................................................................................40

F. Pollution Prevention Plan ..........................................................................................41

G. Dangerous Wastes – Permit by Rule Requirements...............................................42

H. Outfall Evaluation......................................................................................................42

I. Certified Operator........................................................................................................43

J. General Conditions.....................................................................................................43

VI. PERMIT ISSUANCE PROCEDURES...................................................................................43

A. Permit Modifications .................................................................................................43

B. Proposed Permit Issuance .........................................................................................43

VII. REFERENCES FOR TEXT AND APPENDICES................................................................43

APPENDIX A - PUBLIC INVOLVEMENT INFORMATION ...................................................45

APPENDIX B - GLOSSARY........................................................................................................46

APPENDIX C - WASTEWATER TREATMENT FLOW DIAGRAM .......................................50

APPENDIX D - MONTHLY DISCHARGE MONITORING REPORTS ...................................50

APPENDIX E - TECHNICAL LIMIT CALCULATION.............................................................50

APPENDIX F - DRY WEATHER FLOW CALCULATION ......................................................50

APPENDIX G - STORMWATER ALLOCATION EVENTS .....................................................50

APPENDIX H - REASONABLE POTENTIAL TO EXCEED ANALYSIS ...............................50

APPENDIX I - MIXING ZONE ANALYSIS DATA...................................................................50

APPENDIX J - TEMPERATURE ANALYSIS............................................................................50

APPENDIX K - HERRING AND WET TESTING RESULTS ...................................................50

APPENDIX L - PERFORMANCE-BASED REDUCTION OF MONITORING 

FREQUENCY...........................................................................................................................50

APPENDIX M - RESPONSE TO COMMENTS..........................................................................50
Page 1

I. INTRODUCTION

The Federal Clean Water Act (FCWA, 1972, and later modifications, 1977, 1981, and 1987) 

established water quality goals for the navigable (surface) waters of the United States. One 

mechanism for achieving the goals of the Clean Water Act is the National Pollutant Discharge 

Elimination System of permits (NPDES permits), administered by the federal Environmental 

Protection Agency (EPA). The EPA authorized the State of Washington to manage the NPDES 

permit program in our state. Our state legislature accepted the delegation and assigned the power 

and duty for conducting NPDES permitting and enforcement to Ecology. The legislature defined

Ecology's authority and obligations for the wastewater discharge permit program in 90.48 RCW 

(Revised Code of Washington). Ecology adopted rules describing how it exercises its authority:

• Procedures Ecology follows for issuing NPDES permits (Chapter 173-220 WAC),

• Water quality criteria for surface waters and ground waters (Chapters 173-201A and 

Chapter 173-200 WAC),

• Sediment management standards (Chapter 173-204 WAC), and

• Submission of Plans and Reports for Construction of Wastewater Facilities (Chapter 173-

240 WAC)

These rules require any industrial facility operator to obtain an NPDES permit before 

discharging wastewater to state waters. They also help define the basis for limits on each 

discharge and for performance requirements imposed by the permit.

Under the NPDES permit program and in response to a complete and accepted permit 

application, Ecology must prepare a draft permit and an accompanying fact sheet, and make 

them available for public review before final issuance. Ecology must also publish an 

announcement (public notice) telling people where they can read the draft permit, and where to 

send their comments during a period of least thirty days (WAC 173-220-050). (See Appendix A 

- Public Involvement for more detail on the Public Notice and Comment procedures). After the 

public comment period ends, Ecology may make changes to the draft NPDES in response to 

comments. Ecology will summarize the response to comments and any changes to the permit in 

Appendix M.
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II. BACKGROUND INFORMATION

Table 1: General Facility Information

Facility Information

Applicant: Tesoro Refining & Marketing LLC

Facility Name and 

Address:

Tesoro Refining & Marketing LLC

West March Point Road

Anacortes, Washington 98221

Type of Facility: Petroleum Refinery

SIC Code: 2911

Discharge Location: Water Body Name: Fidalgo Bay

Latitude Longitude

Outfall 001 48.508333 122.566667

Outfall 002 48.491667 122.575

Outfall 003 48.5 122.561389

Outfall 004 48.490278 122.575

Permit Status

Renewal Date of Previous Permit April 19, 2006

Application for Permit Renewal Submittal Date November 3, 2010

Amended Application Submittal Date February 21, 2012

Date of Ecology Acceptance of Application May 4, 2011

Inspection Status

Date of Last Non-sampling Inspection November 2012
Page 3

A. Facility Description

Figure 1: Facility Location Map

(Northern half of March Point, Skagit County, WA)

SITE DESCRIPTION AND HISTORY

The refinery is located on the northwestern coast of Washington on March Point, which extends 

into Fidalgo Bay to the west and Padilla Bay to the east. The facility is located in Skagit County, 

approximately two miles east/southeast of the town of Anacortes, Washington.

INDUSTRIAL PROCESS

The refinery was originally constructed in 1955. In 1965, 68,000 barrels (bbl) per day of crude 

oil was processed. Currently the facility has the capacity to process approximately 105,000 to 

115,000 bbl/stream day of crude oil. The main source of crude oil in the last five years has been 

from tankers delivering oil from Alaska's Northern Slope and pipeline delivery oil from Canada. 

Canada has been the primary source of crude for the past several years. Additional crude is now 

supplied via railcar from the Bakken Shale Reserves of Montana and North Dakota. The refinery 

separates crude oil into its various component parts. Separated components are further 

processed and blended into a variety of petroleum products. These products include gasoline, 

turbine and jet fuel, diesel oil, liquid petroleum gas, and residual fuel oil. The refinery directly 

employs about 330 people, and the estimated indirect employment is 280 jobs.
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WASTEWATER TREATMENT

Sanitary wastewater is treated in a septic tank. The effluent from the septic tank is discharged 

into a neutralization pit where spent acid from the refinery boiler feed water demineralization 

process is added. The pH of the chemical wastewater ranges from 2 to 4. The spent acid is added 

once or twice a day in a batch process which keeps the neutralization pit at a low enough pH to 

effectively kill the microorganisms in the septic tank effluent. The neutralization pit effluent is 

added to the end of the API separators at the afterbay. The pH of the wastewater is continuously 

monitored downstream of the neutralization pit addition in the afterbay of the API separator. An 

automated pH adjustment system adds spent acid from the alkylation unit or fresh caustic to the 

API afterbay in order to maintain an optimum pH for the biomass in the aeration basins.

Industrial wastewater (including process wastewater and contaminated stormwater) receives 

primary and secondary treatment in a wastewater treatment system consisting of 2 parallel API 

oil/water separators, 2 primary clarifiers, 2 activated sludge units, 2 secondary clarifiers, and 2

final holding ponds. The total discharge volume generally ranges between 2.0 to 6.0 million 

gallons per day. The highest daily discharge since 2007 was 9.823 million gallons per day. The 

discharge is generally pumped into Fidalgo Bay between the hours of 9 AM to 3 PM. There is 

another potential discharge point, Outfall 002, which could occasionally discharge during high 

rainfall events. It is described later in the fact sheet in the stormwater section.

Tesoro Logistics Operations LLC, Crude Railcar Off-Loading Facility is a new rail car 

unloading facility located at the west end of the refinery. This operation is separately owned and 

operated from the refinery. The proposed permit authorizes the refinery to accept and treat oily 

waste water from the rail yard unloading platform. This amount is estimated to be approximately 

144, 000 gallons per day. This discharge is permitted under State Waste Discharge Permit 

No.ST0045528.

SOLID WASTES

The refinery manages various solid wastes onsite including: garbage, recyclables, (paper, plastic, 

glass, metal, and wood), non-hazardous excavated soil, concrete, and asphalt.

DISCHARGE OUTFALLS

All process water, sanitary wastewater, stormwater, and ballast water is discharged via a 30-inch 

multi-port submerged diffuser at Outfall 001. The refinery's wastewater outfall is supported on 

the Tesoro shipping pier and extends approximately 3400 feet from the shore in a 

north/northwesterly direction into Fidalgo Bay.

Stormwater/Emergency Outfalls 002-004

During extremely heavy rainfall events, Tesoro may discharge water from a retention pond on 

the west side of the refinery to prevent damage to refinery equipment and treatment facilities. 

The discharge points are designated Outfall 002 and Outfall 004. This wastewater would consist
Page 5

almost entirely of stormwater, but may contain small amounts of oily wastewater from drainage 

of the diesel loading rack pad and maintenance of the line supplying the loading rack. This pond 

receives no process wastewater from the refinery's process units. Under normal circumstances, 

Tesoro pumps this stormwater into the refinery's sewer system for processing at the wastewater 

treatment plant. Stormwater was last discharged from these outfalls in November 1990, 

November 1995 and December 1996. Since those incidents, Tesoro has increased the volume of 

this retention pond which has decreased the chances of an overflow or emergency discharge. No 

discharges have occurred at these outfalls since December 1996.

During extremely heavy rainfall events, Tesoro may discharge water through the emergency 

overflow, Outfall 003, located between the East and West Polishing Ponds. The discharge would 

consist of high quality wastewater, treated to secondary treatment levels and would be 

discharged due to a heavy rain exceeding the storage capacity of either pond. Tesoro has not 

discharged from Outfall 003 since prior to 1990.

Tesoro Logistics Operations, Crude Railcar Off-Loading Facility, Stormwater Outfalls 005 and 

006

The construction of the new railcar unloading facility created two new stormwater outfalls 

designated 005 and 006. The stormwater collection systems feeding the outfalls gather runoff 

from the rail facility arrival and departure tracks where rail cars and locomotives are staged. 

Outfall 005 drains a total area of approximately 20 acres to a retention pond before discharging 

the stormwater to a vegetated hillside above March Point Road via a flow spreader. Outfall 006 

drains an area of about 2 acres and discharges directly to a vegetated swale above March Point 

Road. These vegetated slopes will control flow and remove possible sediments from the 

stormwater. Both final outfall stormwater discharges combine with offsite (upslope) stormwater 

before reaching Fidalgo Bay. Because the new railcar facility is owned by a separate entity, 

discharges from stormwater outfalls 005 and 006 are authorized and covered by the Industrial 

Stormwater General Permit. Permit No. WAR126080, issued on August 27, 2012.

B. Summary of Compliance with Previous Permit Issued

Ecology conducts sampling and non-sampling compliance inspections annually at Tesoro. Since 

the current permit was issued in 2006, Ecology has conducted a total of 8 non-sampling and 5

sampling inspections at the refinery. A non-sampling inspection is a walk-through inspection to 

visually check the wastewater treatment system. During a sampling inspection Ecology reviews

laboratory records, and collects samples in addition to the facility walk-through.

The refinery exceeded the total suspended solid permit limit based on one occasion on January 2, 

2007. An extreme rainfall event flushed TSS into the system and the effluent measured 2093 lbs 

for the day which exceeded the limit of 2069 lbs. This is approximately 1.2% over the limit. 

During follow-up conversations the facility indicated this was an extreme event and any reoccurrence would be extremely rare. No TSS violations have occurred during this permit cycle

since this incident.

The refinery also reported one fecal coliform sample above the permit limit that occurred on 

November 5, 2008. The sample measured 660/100 mL which exceeds the limit of 400 
Page 6

colonies/100 mL. This is 65% above the limit. The refinery believed that this result was due to 

a first flush rain event from adjacent farm land ditches providing probable pollutants. The 

facility committed to improving ditch quality around their site so as to prevent fecal intrusion 

from reoccurring. Improved attention towards preventing these exceedances was agreed upon

and implemented with no further incident or enforcement.

A possible facility sampling/lab error/anomaly resulted in a sample value for fecals that 

exceeded permitted levels on June 2, 2010. The sample was tested at 480/100 mL which 

exceeded the daily maximum limit of 400/100 mL. Further testing of samples for this day and 

preceding days could not duplicate the results within an order of magnitude (results were 1-

10/100 mL). Improved attention to sampling and analytical procedures have prevented a 

reoccurrence of this problem. Although technically a violation, Ecology did not issue a penalty.

A facility lab error resulted in a sample value for fecals that exceeded permitted levels on 

October 13, 2011. The sample was tested at 2752/100 mL which exceeded the daily maximum 

limit of 400/100 mL. Lab testing of the sample blank for this day resulted in “numbers to big to 

count”. A lab contamination problem was discovered. Modification of the lab procedures were 

put into place and results returned to normal. Tests up-stream of the compliance point provided 

results that the discharge for this day was below the permit limit of 400/100 mL. Ecology did 

not issue a penalty.

C. Review of Previous Permit Requirements

The previous permit required Tesoro to conduct the following studies and submit reports during 

the permit cycle. Ecology used the data from these reports to prepare this proposed permit.

1. Outfall Evaluation Report:

Tesoro submitted this report on September 20, 2010. All discharge pipes appeared to be 

in good condition. The report fulfills the requirement in the previous permit.

2. Flow Measurement Engineering Report:

Tesoro submitted this report on June 28, 2007. The report fulfills the requirement in the 

previous permit.

3. Treatment Efficiency Study Plan and Engineering Report:

Tesoro submitted this report on October 22, 2010. Ecology determined it met the 

requirements in the previous permit. The evaluation of this report is discussed later in 

this document.

4. Sediment Study:

The refinery submitted this report in 2001. The evaluation of this report is discussed later 

in this document.

5. Dioxin Study and AKART Engineering Report:

The refinery submitted the Dioxin Study and AKART Engineering Report to Ecology on 

March 12, 2009.
Page 7

The previous permit also required Tesoro to sample the chlorinated dioxins and furans 

(2,3,7,8-Cl substituted tetra-through octa-congeners) concentrations as follows:

• In the wastewater stream from each of the catalytic reformer regenerations

• In the final effluent most likely to contain wastewater generated during the 

catalytic reformer regeneration events sampled for dioxins

The sampling results indicated that the most toxic compound of the chlorinated 

dioxin/furan congeners (2,3,7,8 TCDD) was detected in the wastewater stream from the

Catalytic Reformer. The highest measured concentration was 103 ppq. No dioxins or 

furans were detected in the final effluent. The proposed permit requires Tesoro to monitor 

the chlorinated dioxin and furan (2,3,7,8-Cl substituted tetra-through octa-congeners) 

concentrations in the final effluent at Outfall 001 and the upstream wastewater from the 

catalytic reformer units twice during the next permit cycle.

The AKART report concluded that the existing waste water treatment system is the Best 

Available Technology (BAT) to treat dioxin at the refinery. After reviewing this report 

Ecology agreed with this conclusion.

6. Treatment System Operating Plan (TSOP):

The refinery submitted an updated TSOP to Ecology on August 24, 2010. The TSOP met 

the requirements in the previous permit.

7. WET Testing Reports:

The results are described later in this document.

8. Mercury P2 Plan:

The refinery submitted the initial plan to Ecology on April 16, 2007 with updates on

2009, 2010, 2011, and on March 27, 2012. This plan attempted to identify possible 

linkages between the Hg content of crude oils coming into the refinery and any Hg in the 

final discharge of effluent. No linkages could be established and all effluent samples 

were compliant with the permit limits. The plan met the requirements in the previous 

permit.

D. Wastewater Characterization

Tesoro characterized the wastewater discharge at outfall 001 in the permit application process 

for: conventional pollutants, metals, cyanide, volatile organic compounds, acid compounds, base 

neutral compounds, and pesticides. The long term average values reported below for Outfall 001 

are based on extensive (daily to weekly) monitoring completed during the term of the current 

permit.

The values in Table 2 are for pollutants with significant concentrations and/or of interest and 

metals and organics that were quantified at greater than detection limits. This information is 

from the NPDES permit renewal application received on November 3, 2010 and annual priority 

pollutant results for metals.
Page 8

Table 2: Wastewater Characterization for Outfall 001 (Long Term Averages except where 

noted)

Parameter Concentration (mg/l) Mass (lb/day)

BOD 5.9 142

COD 49 1119

TSS 9 217

Ammonia as N 1.0 18

Flow 2.8 MGD

Temperature Winter 14.8 oC Summer 26.4 oC

pH Minimum 6.1 SU Maximum 9.2 SU

Oil & Grease 3 71

Sulfide 0.013 0.28

Phenols (Total) 0.009 0.217

Parameter Concentration (μg/l) Mass (lb/day)

Arsenic (Total) 5.33 0.1168

Copper (Total) 5.01 0.1157

Nickel (Total) 5.33 0.1168

Selenium (Total) 13.0 0.3038

Zinc (Total) 66 1.54

Mercury (Total) 0.100 0.0023

Cyanide (Total) 7.0 0.1636

E. Description of the Receiving Water

Tesoro discharges to Fidalgo Bay, which is designated as an extraordinary marine receiving 

water in the vicinity of Outfall 001.
Page 9

Other nearby point source outfalls includes the Shell Oil Products US - Puget Sound Refining 

Company and the Anacortes City POTW. The Shell wastewater treatment plant outfall is located 

in the vicinity of the Tesoro outfall at a Latitude of 48.509744 and a Longitude of 122.57694. 

The outfalls are physically located within 3000 feet of each other. For the city of Anacortes, 

treated water from the wastewater treatment plant is piped out into the Guemes Channel. The end 

of the pipe is located just to the west of the Port of Anacortes Pier 2. This outfall is 

approximately 2 miles from the Tesoro outfall.

The closest Ecology long-term core monitoring station, GRG002, is located in the Strait of 

Georgia near Patos Island. It is far enough away from the Cherry Point industries to prevent 

their discharges from influencing readings taken there. There is also substantial data for this 

station. The station at Bellingham Bay, BLL009, is also very close but is influenced by activity 

in Bellingham and is not suitable for a background data station. The closest long-term rotating 

station is LOP001 in Lopez Sound.

The table below includes the ambient background for 90th percentile temperature calculated from 

January 1999 through June 2005 at Station GRG002 and the metal concentrations taken from the 

Background Metals Concentrations in Selected Puget Sound Marine Receiving Waters prepared 

by Eric Crecelius, Battelle Marine Sciences Laboratory, February 1998.

 

 Table 3: Ambient Background Data

Parameter Value Used

Temperature (90th percentile) 11.8 0C

Ammonia 16 ug/L

Aluminum 45.2 ug/L

Cadmium 0.059 ug/L

Copper 0.673 ug/L

Lead 0.146 ug/L

Mercury 0.001 ug/L

Zinc 3.9 ug/L

F. SEPA Compliance

Regulation exempts reissuance or modification of any wastewater discharge permit from the 

SEPA process as long as the permit contains conditions that are no less stringent than state rules 

and regulations. The exemption applies only to existing discharges, not to new discharges.

III. PROPOSED PERMIT CONDITIONS

Federal and State regulations require that effluent limitations set forth in a NPDES permit must 

be either technology or water quality-based.
Page 10

• Technology-based limits are based upon the treatment methods available to treat specific 

pollutants. Technology-based limits are set by the EPA and published as a regulation, or 

Ecology develops the limit on a case-by-case basis (40 CFR 125.3, and Chapter 173-220 

WAC).

• Water quality-based limits are calculated so that the effluent will comply with the Surface 

Water Quality Standards (Chapter 173-201A WAC), Ground Water Standards (chapter 

173-200 WAC), Sediment Quality Standards (Chapter 173-204 WAC) or the National 

Toxics Rule (40 CFR 131.36).

• Ecology must apply the most stringent of these limits to each parameter of concern. 

These limits are described below.

The limits in this permit reflect information received in the permit renewal application and from 

supporting reports (engineering, priority pollutant sampling, etc.). Ecology evaluated the permit 

application and determined the limits needed to comply with the rules adopted by the State of 

Washington. Ecology does not develop effluent limits for all reported pollutants. Some 

pollutants are not treatable at the concentrations reported, are not controllable at the source, are 

not listed in regulation, and do not have a reasonable potential to cause a water quality violation.

Ecology does not usually develop permit limits for pollutants that were not reported in the permit 

application but that may be present in the discharge. The permit does not authorize discharge of 

the non-reported pollutants. During the five-year permit term, the facility’s effluent discharge 

conditions may change from those conditions reported in the permit application. The facility 

must notify Ecology, as described in 40 CFR 122.42(a), if significant changes occur in any 

constituent. Industries may be in violation of their permit until Ecology modifies the permit to 

reflect additional discharge of pollutants.

A. Design Criteria

Under WAC 173-220-150(1)(g), neither flows nor waste loadings may exceed approved design 

criteria. Ecology approved the following design criteria for the refinery’s wastewater treatment 

plant. The design criteria for this treatment facility were obtained from Tesoro correspondence 

from April 2000, January 4, 2005, July 25, 2005, and the updated October 19, 2010 engineering 

reports prepared by Tesoro. 

Table 4: Design Standards

Flows or waste loadings of the following design criteria for the permitted treatment 

facility shall not be exceeded: 

Process Wastewater treatment plant capacity (prior to commingling with non-process area 

storm water)

Average monthly flow for the maximum month1 4.3 MGD

Average monthly COD for the maximum month2 1700 mg/l

1 as measured at influent to the API

2 as measured at the primary clarifier
Page 11

B. Technology-Based Effluent Limits

PROCESS WASTEWATER

Ecology calculated effluent limits for the Tesoro refinery based on Best Conventional Pollutant 

Control Technology (BCT), Best Available Technology Economically Achievable (BAT), Best 

Practicable Control Technology Currently Available (BPT), and New Source Performance 

Standards (NSPS) developed by the Environmental Protection Agency (EPA). Guidelines were 

published August 12, 1985 under 40 CFR Part 419 by the Environmental Protection Agency 

(EPA) for the cracking subcategory of petroleum refining.

The refinery effluent limitations are based on terms of a settlement agreement dated April 17, 

1984, between EPA and the Natural Resources Defense Council resolving litigation about the 

EPA guidelines. The August 12, 1985 guidelines establish Best Available Technology (BAT) 

and Best Conventional Technology (BCT) as equal to Best Practicable Technology (BPT) for all 

parameters except phenols and chromium. Phenols and chromium are regulated by whichever 

guideline is more stringent.

In 1996, EPA completed a study of the petroleum refining industry (EPA-821-R-96-015) 

including treatment technologies, pollutants discharged, pollutant loadings, and potential water 

quality impacts. Based upon this review, EPA decided not to revise the refinery effluent 

guidelines. EPA determined that the best treatment technology currently available was 

essentially the same as that applied at the time the effluent guidelines were originally 

promulgated. EPA also determined that if the wastewater treatment systems at the refineries are 

properly operated and maintained, priority pollutants will be removed or treated to negligible or 

below detectable levels.

In addition, Ecology requires facilities to use all known, available, and reasonable methods to 

control toxicants (AKART) in its wastewater as required under Washington State regulations. 

Because Ecology applies new source performance standards (NSPS) on the basis of the AKART 

requirements, the refinery’s NPDES permit limits are more stringent than those in other states. 

Ecology has applied the more stringent NSPS limits to all crude throughput increases since 1984.

On December 31, 2003, EPA published its intention to review the petroleum refining industry 

again to decide the necessity for revising their effluent guidelines. EPA evaluated pollution 

prevention opportunities, emerging treatment technologies, revising the effluent guidelines, and 

expanding the list of regulated pollutants. EPA reviewed information and comments on several 

issues including: control technologies for polycyclic aromatic hydrocarbons (PAHs), dioxin 

sources and reduction/control technologies, sources of toxic metals, process modifications to 

reduce metals, and what toxics are being released and remain unreported.

On September 2, 2004 (Federal Register Volume 69 No. 170), EPA published its decision 

regarding revising the refinery effluent guidelines. EPA concluded that there is little evidence 

that PAHs are present in refinery wastewater discharges in concentrations above the detection 

limit. It also concluded that the concentration of metals being discharged by refineries is at or 

very near treatable levels, leaving little to no opportunity to reduce metals discharges through 

conventional end-of-pipe treatment.
Page 12

EPA reviewed the available dioxin information collected by refineries nationwide much of which 

was collected at the Washington state refineries. The overall data indicated that dioxins are only 

occasionally discharged in relatively low concentrations in treated refinery effluent. In its 

opinion, this data did not warrant the development of national categorical limitations on dioxin in 

refinery wastewater discharges. EPA did note that on a case-by-case, best professional judgment 

basis, permit writers may decide to include effluent limitations for dioxin.

EPA also encouraged permit writers and refineries to consider pollution prevention 

opportunities. As a result of their evaluation, EPA concluded that there was no need to revise the 

federal effluent guidelines at this time.

Ecology must decide whether the effluent guidelines also constitute all known, available and 

reasonable methods of treatment (AKART). As a general rule, if the effluent guidelines for a 

particular category are 5 years old or less, they are considered to be AKART. This will be 

immediately apparent in reviewing the development document. The development document 

describes production processes, pollutants generated, treatment efficiencies, and unit process 

designs present nationwide in the specific industry at the time of effluent guideline development.

Generally, when effluent guidelines are over 10 years old, Ecology will analyze unit process 

designs and efficiencies to determine that the effluent guidelines constitute AKART and meet the 

intent of RCW 90.48.520. The previous NPDES permit required Tesoro to prepare a treatment 

efficiency study and an engineering report describing the treatment capacity of the wastewater 

facility.

Ecology compared Tesoro’s production processes, pollutants generated, and treatment 

technology to EPA’s original development document and the results of EPA’s 1996 and 2004 

evaluations of the petroleum refining industry. Ecology also examined the treatability data base 

and Tesoro’s wastewater treatment design and efficiencies. Ecology determined that Tesoro is 

providing AKART for its wastewater.

Since Ecology issued the previous NPDES permit (May 1, 2006), Tesoro's crude oil throughput 

rate has changed. The daily average throughput rate ranged from 59,000 to 130,000 bbls/day.

The rate changes in refinery processes are shown in the table below. The size and process factor 

determination is documented in Appendix E. Ecology multiplied these factors by the actual feed 

stock to obtain an adjusted feed stock that is used in determining effluent limits, except for 

determining BAT limits for phenols and chromium.

Table 5: Refinery Process Throughput

Production Rates 

(bbls/day) and Factors

1990 Permit 1998 Permit 2006 Permit Proposed 

Permit

Actual Feed Stock 85,400* 110,000 113,600 114,300

Desalting 85,400 117,100 119,600 115,300
Page 13

Production Rates 

(bbls/day) and Factors

1990 Permit 1998 Permit 2006 Permit Proposed 

Permit

Atmospheric Distillation, 85,400 110,000 113,600 114,300

Vacuum Distillation 34,000 34,000 42,800 47,200

Fluid Catalytic Cracking 35,900 44,300 43,300 46,400

Propane Deasphalting 15,100 13,800 14,000 22,000

Hydrotreating** 19,000 69,900 61,000 67,000

H2SO4 Alkylation 9,000 12,400 11,300 12,000

Catalytic Reforming** 15,000 23,200 23,800 31,000

Process Factor 1.29 1.29 1.29 1.29

Size Factor 1.13 1.23 1.23 1.23

Adjusted Feedstock 121,236 147,477 152,304 181,360

New Source Performance 

Increment

23,380 49,540 54,376 83,423

* All feedstock rates specified in this table represent actual crude throughput less slop oil 

and other recycled material.

** Baseline values for these processes are used to calculate BAT limitations for phenols and 

chromium.

Increases in the feed stock rate are subject to limitations that Ecology determined to be the 

treatment level obtained from using all known available and reasonable treatment methods. The 

increases are subject to New Source Performance Standards (NSPS) on the basis of AKART. 

Ecology calculated the NSPS limitations by multiplying the increase in adjusted feed stock,

(181,360 – 97,937 = 83,423 bbls/day) by New Source Performance Standards. It added the 

resulting NSPS increment, based upon 83,423 bbls/day, to the BAT and BPT limitations, based 

upon the adjusted baseline feedstock rate of 97,937 bbls/day. Ecology did not include BCT 

limitations because they are equivalent to BPT limitations.

The Environmental Protection Agency determined federal effluent guidelines for total and 

hexavalent chromium back when chromium was commonly used in cooling water systems and

discharged at much higher levels in the effluent. Chromium was banned for use in cooling 

systems by EPA in the early 1990s and the only remaining source of chromium is in the crude 

oil. Because federal effluent guidelines still include limits for chromium, Ecology must include 

an effluent limit for chromium in the proposed permit to ensure that refineries in Washington are 

subject to the same requirements as refineries located in other states.
Page 14

Ecology believes the guideline-derived effluent limit is artificially high now that chromium in 

the effluent has decreased to levels bordering on non-detectable. All detectable samples of 

chromium in the Tesoro effluent have been within the range of 5 to 11 μg/l which is less than 

1/10th of the marine chronic water quality standard of 50 μg/l for hexavalent chromium (acute 

standard = 1100 μg/l). Approximately half of the samples collected during the last 5 years have 

been non-detectable for chromium.

Based on this information, Ecology’s Best Professional Judgment is that a 50 μg/l hexavalent 

chromium concentration limit is technologically achievable, reasonable, and protective of the 

receiving water quality. The proposed permit condition imposes the 50 μg/l as a technologybased limit and not as a water quality-based limit.

At a 2.62 MGD effluent flow (dry weather), the 50 μg/l limit converts to 1.12 lbs/day. This limit 

is more stringent than the federal effluent guideline BAT limit of 1.52 lbs/day. At lower effluent 

flows, this limit will continue to be more stringent than the federal effluent guideline limit. 

However, at higher effluent flows, the federal effluent guideline limit will be more stringent. 

Therefore, the proposed permit includes both a concentration limit of 50 μg/l and a mass-based 

BAT limit of 1.52 lbs/day to cover all flow situations that might occur.

 

The technology-based hexavalent chromium limit replaces the total chromium limits and the 

hexavalent chromium limits in previous permits.

If chromium levels change in the crude oil refined at Tesoro and result in concentration 

increases, Ecology will modify the permit to increase the limit as needed to allow continued 

facility compliance. Ecology will evaluate any revised limit to ensure that the effluent continues 

to meet water quality standards within the authorized mixing zone and the anti backsliding 

requirements are met and to ensure that chromium concentrations do not exceed limits allowed 

under the federal effluent guidelines. In the event that the federal effluent guidelines are 

promulgated without chromium limits, Ecology will drop the limit from the permit unless the 

situation changes and a water quality limit is necessary. Tesoro will continue to perform semiannual hexavalent chromium monitoring.

The effluent limit calculations are tabulated in Appendix E. The calculated limits are based on 

the NSPS increment and the more stringent of the BAT and BPT determinations. BAT 

limitations are more stringent than BPT for phenol and chromium.

The state’s antidegradation program is discussed later in this document. The federally mandated 

program has three tiers of protection. The Tier II antidegradation provisions limit the conditions 

under which waters of higher quality than standards can be degraded. A Tier II analysis is 

required for new or expanded sources of pollution from specific activities regulated by Ecology. 

A greater than 10% increase to an existing effluent concentration or mass limit in an NPDES 

permit is considered an expanded action. The effective date of new or expanded actions is 

defined in WAC 173-201A-020 as those actions that result in an increase in pollution after July 

1, 2003.
Page 15

For purposes of evaluating a greater than 10% increase, Ecology set the baseline as those effluent 

limits that applied in July 2003. In this case, the baseline is the Level 2 effluent limits in the 

NPDES permit issued to Tesoro in March, 1998.

The calculated effluent limits based on production are greater than 10% of the limits in Tesoro’s 

1998 permit. For Ecology to consider applying the higher limits to Tesoro’s discharge, Tesoro 

must conduct a Tier II analysis. The Tier II analysis is used to ensure that waters of higher 

quality than standards are not degraded unless Ecology determines that lowering the water 

quality is necessary and in the overriding public interest. Based on the outcome of the Tier II 

analysis, Ecology may reopen the permit or revisit the effluent limits during the next permit 

renewal. Public involvement with the Tier II review will be conducted in accordance with the 

public involvement processes associated with the NPDES permit.

The proposed permit includes effluent limits that are 10% higher than the effective limits in 

Tesoro’s 1998 permit. This increase in limits does not require a Tier II analysis. The proposed 

limits are shown in Table 6 below.

Table 6: Proposed Effluent Limits

PARAMETER Units

Baseline Effluent Limits

(from 1998 Permit)

10 % Increase from 

Baseline Limits

July 2003

Monthly 

Average

July 2003

Daily 

Maximum

Proposed

Monthly 

Average

Proposed

Daily 

Maximum

Biochemical 

Oxygen Demand 

(5-day)

lbs/day 690 1,260 760 1,390

Chemical Oxygen 

Demand 

lbs/day 4,800 9,300 5,280 10,230

Total Suspended 

Solids 

lbs/day 560 870 620 960

Oil and Grease lbs/day 200 380 220 420

Oil and Grease mg/l The concentration of oil and grease in the discharge shall 

at no time exceed 15 mg/l and shall not exceed 10 mg/l 

more than three days per month.

Phenolic 

Compounds 

lbs/day 4.5 9.3 5.0 10.2

Ammonia as N lbs/day 440 970 480 1,070

Sulfide lbs/day 3.7 8.2 4.0 9.0

Hexavalent lbs/day 0.6 1.3 -- 1.52 lbs/day 
Page 16

PARAMETER Units

Baseline Effluent Limits

(from 1998 Permit)

10 % Increase from 

Baseline Limits

July 2003

Monthly 

Average

July 2003

Daily 

Maximum

Proposed

Monthly 

Average

Proposed

Daily 

Maximum

Chromium and 

mg/l 

and 

0.050 mg/l 

Fecal Coliforms Organism

/100ml

200 400 200 400

BALLAST AND STORMWATER ALLOCATIONS

Contaminated stormwater from the process area is collected by the oily water sewer and

conveyed to the wastewater facility for treatment. Stormwater runoff generated from the 

wastewater treatment area is discharged ordinarily to the stormwater flume but it can be routed 

back to the wastewater treatment plant and treated if necessary. Stormwater from the tank farms 

and the rest of the industrial site is collected in the stormwater system and diverted to the

stormwater flume. Some settling occurs in the flume and oil and grease can be skimmed from the 

surface as necessary. Stormwater is then routed to the west retention pond where it is 

commingled with the treated process wastewater prior to final discharge. Tesoro can discharge 

petroleum contaminated ballast water into the process wastewater treatment system, but has not 

during the last 5 years.

Stormwater is not directly measured at the facility. Direct measurement of total stormwater is 

not possible since a portion of the stormwater is diverted into the oily water sewer at many 

collection points, and a portion of the stormwater is collected in the stormwater system. The 

stormwater flow is calculated by subtracting an estimated dry weather flow from the total flow 

discharged each day.

Dry weather flow for current conditions was estimated by evaluating total flow during dry 

weather time periods at the facility. This estimate was determined to be 2.62 MGD. The data 

used in the dry weather flow estimate is presented in Appendix F.

 

The ballast and stormwater allocations in the permit are based on guidelines in 40 CFR 419.12(c) 

and 419.22(e). The proposed permit does not include a stormwater allocation for chromium as 

provided for in the federal effluent guidelines. The allocations for stormwater were developed to 

apply to runoff from areas associated with industrial activity. During the months of June through 

October, Tesoro may only claim the stormwater allocation when it can demonstrate that 

measurable rainfall has occurred at the refinery site during the previous 10 calendar days. 

Ecology chose ten days because when big storms hit it takes approximately that amount of time 

to discharge accumulated stormwater. Tesoro may retain stormwater within the north tank dike 

ponds or in dedicated tanks during rain events to the extent possible and slowly discharges 
Page 17

stormwater into the stormwater system following rain events to maximize the settling that occurs 

through the stormwater system. Should the on-site means of measuring rainfall be unavailable 

due to equipment malfunction, Tesoro may use rainfall data from other nearby industries or the 

National Weather Service station at Anacortes.

Table 7: Stormwater and Ballast Water Allocations

Parameter Stormwater Allocation 

(lbs/million gallons)

 Ballast Water Allocation 

(lbs/million gallons)

Monthly Average Daily 

Maximum

Monthly Average Daily Maximum

Biochemical Oxygen 

Demand (5-day)

220 400 210 400

Chemical Oxygen 

Demand

1500 3000 2000 3900

Total Suspended Solids 180 280 170 260

Oil and Grease 67 130 67 126

Tesoro claimed the stormwater allocation once for BOD, 24 times for TSS, and 8 times for oil 

and grease during the last permit cycle. Appendix G shows the monitoring periods when Tesoro 

claimed the stormwater allocations.

STORMWATER/EMERGENCY OVERFLOW MONITORING (OUTFALLS 002/003/004)

There were no discharges from outfalls 002, 003, and 004 during the previous permit term. 

In the event of a discharge from Outfall 002, 003, or 004, the proposed permit requires Tesoro to 

characterize the quality of the effluent discharged. The facility must monitor pH, BOD, TSS, 

COD, oil and grease, lead, zinc, volatile organics, base neutral acids (BNAs), and phenols. 

Ecology chose these parameters based on knowledge of the characteristics of the materials 

handled at the truck rack and the constituents detected in the stormwater flume discharge. When 

contaminated with oily materials, this monitoring is consistent with the types of analyses 

required for the final effluent discharged to the bay.

Tesoro must estimate the flow for any discharge from outfalls 002, 003, and 004 and report it 

along with the sampling results from these outfall’s discharges with the monthly discharge 

monitoring report.
Page 18

FINAL EFFLUENT DISCHARGE FOR FIREWATER TESTING

The proposed permit authorizes Tesoro to use treated final effluent for monthly firewater testing 

supply and during Emergency Response Team (ERT) training. It does not authorize the use of 

foam during the firewater testing or ERT training.

CONSTRUCTION STORMWATER 

Tesoro will need to apply for coverage under the Construction Stormwater General Permit for 

future construction projects that disturb one or more acres and discharge to surface waters of the 

state. Discharges from construction activities at the refinery are not covered by the proposed 

NPDES permit.

C. Surface Water Quality-Based Effluent Limits

The Washington State Surface Water Quality Standards (Chapter 173-201A WAC) were 

designed to protect existing water quality and preserve the beneficial uses of Washington's 

surface waters. Waste discharge permits must include conditions that ensure the discharge will 

meet established surface water quality standards (WAC 173-201A-510). Water quality-based 

effluent limits may be based on an individual waste load allocation or on a waste load allocation 

developed during a basin wide total maximum daily loading study (TMDL).

NUMERICAL CRITERIA FOR THE PROTECTION OF AQUATIC LIFE

Numerical water quality criteria are published in the Water Quality Standards for Surface Waters 

(chapter 173-201A WAC). They specify the levels of pollutants allowed in receiving water to 

protect aquatic life and recreation in and on the water. Ecology uses numerical criteria along 

with chemical and physical data for the wastewater and receiving water to derive the effluent 

limits in the discharge permit. When surface water quality-based limits are more stringent or 

potentially more stringent than technology-based limits, the discharge must meet the water 

quality-based limits.

NUMERICAL CRITERIA FOR THE PROTECTION OF HUMAN HEALTH 

The U.S. EPA has published 91 numeric water quality criteria for the protection of human health 

that are applicable to dischargers in Washington State (40 CFR 131.36). These criteria are 

designed to protect humans from exposure to pollutants linked to cancer and other diseases, 

based on consuming fish and shellfish and drinking contaminated surface waters. The Water 

Quality Standards also include radionuclide criteria to protect humans from the effects of 

radioactive substances. 

NARRATIVE CRITERIA

Narrative water quality criteria (e.g., WAC 173-201A-240(1); 2006) limit the toxic, radioactive, 

or other deleterious material concentrations that the facility may discharge to levels below those 

which have the potential to:
Page 19

• Adversely affect designated water uses.

• Cause acute or chronic toxicity to biota.

• Impair aesthetic values.

• Adversely affect human health.

Narrative criteria protect the specific designated uses of all fresh waters (WAC 173-201A-200, 

2006) and of all marine waters (WAC 173-201A-210, 2006) in the State of Washington.

ANTIDEGRADATION

The purpose of Washington's Antidegradation Policy (WAC 173-201A-300-330; 2006) is to:

• Restore and maintain the highest possible quality of the surface waters of Washington.

• Describe situations under which water quality may be lowered from its current condition.

• Apply to human activities that are likely to have an impact on the water quality of surface 

water.

• Ensure that all human activities likely to contribute to a lowering of water quality, at a 

minimum, apply all known, available, and reasonable methods of prevention, control, and 

treatment (AKART).

• Apply three Tiers of protection (described below) for surface waters of the state. 

Tier I ensures existing and designated uses are maintained and protected and applies to all waters 

and all sources of pollutions. Tier II ensures that waters of a higher quality than the criteria 

assigned are not degraded unless such lowering of water quality is necessary and in the 

overriding public interest. Tier II applies only to a specific list of polluting activities. Tier III 

prevents the degradation of waters formally listed as "outstanding resource waters," and applies 

to all sources of pollution.

A facility must prepare a Tier II analysis when all three of the following conditions are met: 

• The facility is planning a new or expanded action.

• Ecology regulates or authorizes the action.

• The action has the potential to cause measurable degradation to existing water quality at 

the edge of a chronic mixing zone.

The proposed permit increases the limits by 10% but not greater than 10% therefore this facility 

must meet Tier I requirements.

• Dischargers must maintain and protect existing and designated uses. Ecology may not 

allow any degradation that will interfere with, or become injurious to, existing or 

designated uses, except as provided for in Chapter 173-201A WAC.
Page 20

• For waters that do not meet assigned criteria, or protect existing or designated uses, 

Ecology will take appropriate and definitive steps to bring the water quality back into 

compliance with the water quality standards.

• Whenever the natural conditions of a water body are of a lower quality than the assigned 

criteria, the natural conditions constitute the water quality criteria. Where water quality 

criteria are not met because of natural conditions, human actions are not allowed to 

further lower the water quality, except where explicitly allowed in this Chapter.

This section of the fact sheet describes Ecology’s Tier I analysis. The analysis demonstrates that 

the existing and designated uses of the receiving water will be protected under the conditions of 

the proposed permit.

Ecology reviewed existing water quality data from Ecology’s long-term monitoring station 

GRG002 and from Eric Crecelius (1998). The data show that the ambient water meets the 

temperature, dissolved oxygen, pH, turbidity, ammonia, cyanide and metals standards for 

marine waters extraordinary quality category given in Chapter 173-201A WAC. Therefore, 

Ecology uses the designated classification criteria for this water body in the proposed permit. 

The discharges authorized by this proposed permit should not cause a loss of beneficial uses.

Earlier in this fact sheet, Ecology determined that the technology-based effluent limits calculated 

for Tesoro’s discharge meet the definition of an expanded action and trigger a Tier II analysis. 

Should Tesoro choose to conduct a Tier II analysis, the analysis must determine if the expanded 

action has the potential to cause a measurable change in the physical, chemical, or biological 

quality of the receiving water. Any expanding discharger that would cause a measurable 

degradation must go through a technology review to identify and apply any feasible alternatives 

to that degradation and show that overriding public benefits would occur from allowing the 

lowering of water quality.

MIXING ZONES 

A mixing zone is the defined area in the receiving water surrounding the discharge port(s), where 

wastewater mixes with receiving water. Within mixing zones, the pollutant concentrations may 

exceed water quality numeric criteria, so long as the diluted wastewater doesn’t interfere with 

designated uses of the receiving water body (e.g., recreation, water supply, and aquatic life and 

wildlife habitat, etc.). The pollutant concentrations outside of mixing zones must meet water 

quality numeric criteria.

State and federal rules allow mixing zones because the concentrations and effects of most 

pollutants diminish rapidly after discharge, due to dilution. Ecology defines mixing zone sizes to 

limit the amount of time any exposure to the end-of-pipe discharge could harm water quality, 

plants, or fish.

The State’s Water Quality Standards allow Ecology to authorize mixing zones for the facility’s 

permitted wastewater discharges only if those discharges already receive all known, available, 

and reasonable methods of prevention, control and treatment (AKART). Mixing zones typically 
Page 21

require compliance with water quality criteria within a specified distance from the point of 

discharge; and use no more than 25% of the available width of the water body for dilution. 

Ecology uses modeling to estimate the amount of mixing within the mixing zone and determine 

the potential for violating the water quality standards at the edge of the mixing zone and derive 

any necessary effluent limits. Steady-state models are the most frequently used tools for 

conducting mixing zone analyses. Ecology chooses values for each effluent and for receiving 

water variables that correspond to the time period when the most critical condition is likely to 

occur (see Ecology’s Permit Writer’s Manual). Each critical condition parameter (by itself) has 

a low probability of occurrence and the resulting dilution factor is conservative. The term 

“reasonable worst-case” applies to these values.

The mixing zone analysis produces a numerical value called a dilution factor (DF). A dilution 

factor represents the amount of mixing of effluent and receiving water that occurs at the 

boundary of the mixing zone. For example, a dilution factor of 10 means the effluent comprises 

10% by volume and the receiving water comprises 90% of the total volume at the boundary of 

the mixing zone. Ecology uses dilution factors with the water quality criteria to calculate 

reasonable potentials and effluent limits. Water quality standards include both aquatic life-based 

criteria and human health-based criteria. The former are applied at both the acute and chronic 

mixing zone boundaries; the latter are applied only at the chronic boundary. The concentration of 

pollutants at the boundaries of any of these mixing zones may not exceed the numerical criteria 

for that zone.

Each aquatic life acute criterion is based on the assumption that organisms are not exposed to 

that concentration for more than one-hour and more often than one exposure in three years. Each 

aquatic life chronic criterion is based on the assumption that organisms are not exposed to that 

concentration for more than four consecutive days and more often than once in three years.

The two types of human health-based water quality criteria distinguish between those pollutants 

linked to non-cancer effects (non-carcinogenic) and those linked to cancer effects (carcinogenic). 

The human health-based water quality criteria incorporate several exposure and risk 

assumptions. These assumptions include:

• A 70-year lifetime of daily exposures.

• An ingestion rate for fish or shellfish measured in kg/day.

• An ingestion rate of two liters/day for drinking water

• A one-in-one-million cancer risk for carcinogenic chemicals.

This permit authorizes a small acute mixing zone, surrounded by a chronic mixing zone around 

the point of discharge (WAC 173-201A-400; 2006). The water quality standards impose certain 

conditions before allowing the discharger a mixing zone:

1. Ecology must specify both the allowed size and location in a permit.

The proposed permit specifies the size and location of the allowed mixing zone.

2. The facility must fully apply AKART to its discharge.
Page 22

Ecology has determined that the treatment provided for the discharge at Outfall 001 and the 

pollution prevention activities practiced at Tesoro meet the requirements of AKART (see 

“Technology based Limits”).

3. Ecology must consider critical discharge conditions.

Surface water quality-based limits are derived for the water body’s critical condition, (the 

receiving water and waste discharge condition with the highest potential for adverse impact on 

the aquatic biota, human health, and existing or designated water body uses). The critical 

discharge condition is often pollutant-specific or water body-specific.

Critical discharge conditions are those conditions that result in reduced dilution or increased 

effect of the pollutant. Factors affecting dilution include the depth of water, the density 

stratification in the water column, the currents, and the rate of discharge. Density stratification is 

determined by the salinity and temperature of the receiving water. Temperatures are warmer in 

the surface waters in summer. Therefore, density stratification is generally greatest during the 

summer months. Density stratification affects how far up in the water column a freshwater 

plume may rise. The rate of mixing is greatest when an effluent is rising. The effluent stops 

rising when the mixed effluent is the same density as the surrounding water. After the effluent 

stops rising, the rate of mixing is much more gradual. Water depth can affect dilution when a 

plume might rise to the surface when there is little or no stratification. Ecology uses the water 

depth at mean lower low water (MLLW) for marine waters.

Ecology’s Permit Writer’s Manual describes additional guidance on criteria/design conditions for 

determining dilution factors. The Manual can be obtained from Ecology’s website at: 

http://www.ecy.wa.gov/biblio/92109.html.

Ecology used the following critical conditions to model the discharge:

• Water depth at MLLW of 25 feet.

• Density profile with a difference of 8.18 sigma-t units between 25 feet and the surface.

• 50th percentile current speeds of 5.5 cm/sec for chronic and human health mixing zones.

• 10th percentile current speeds of 1.0 cm/sec for acute mixing zone.

• Maximum average monthly effluent flow of 4.5 MGD for chronic and human health noncarcinogen.

• Annual average flow of 2.8 MGD for human health carcinogen.

• Maximum daily flow of 7.78 million gallons per day (MGD) for acute mixing zone.

• 1 DAD MAX Effluent temperature of 31.7 degrees C.

4. Supporting information must clearly indicate the mixing zone would not:

• Have a reasonable potential to cause the loss of sensitive or important habitat,

• Substantially interfere with the existing or characteristic uses,

• Result in damage to the ecosystem, or

• Adversely affect public health.
Page 23

Ecology established Washington State water quality criteria for toxic chemicals using EPA 

criteria. EPA developed the criteria using toxicity tests with numerous organisms, and set the 

criteria to protect all aquatic species.

EPA sets acute criteria for toxic chemicals assuming organisms are exposed to the pollutant at 

the criteria concentration for 1-hour. They set chronic criteria assuming organisms are exposed to 

the pollutant at the criteria concentration for 4 days. Dilution modeling under critical conditions 

generally shows that both acute and chronic criteria concentrations are reached within minutes of 

being discharged.

The discharge plume does not impact drifting and non-strong swimming organisms because they 

cannot stay in the plume close to the outfall long enough to be affected. Strong swimming fish 

could maintain a position within the plume, but they can also avoid the discharge by swimming 

away. Mixing zones generally do not affect benthic organisms (bottom dwellers) because the 

buoyant plume rises in the water column. Ecology has additionally determined that the 

discharge at Outfall 001 will not exceed 33 degrees C for more than 2 seconds after discharge 

and that the temperature of the receiving water after mixing with the discharge will not create 

lethal conditions or blockages to fish migration.

Ecology evaluates the cumulative toxicity of an effluent by testing the discharge with whole 

effluent toxicity (WET) testing. WET testing performed by Tesoro for Outfall 001 indicates that 

there is no reasonable potential for acute or chronic receiving water toxicity.

The mixing zone for Outfall 001 is small and is centered at a distance of 2434 feet from shore. 

The mixing zone does not lie near the herring spawning areas, which are closer to shore.

There is no documented link between Tesoro’s discharge at Outfall 001 and the decline in the 

local herring population. Tesoro will use the recently developed herring bioassay tests to 

evaluate the possible effects of their effluent on herring and to compare the herring bioassay 

results with other EPA approved bioassay tests.

Ecology reviewed the above information, the specific information on the characteristics of the 

discharge, the receiving water characteristics, and the discharge location. Based on this review 

Ecology concluded that the discharge at Outfall 001 does not have a reasonable potential to 

cause the loss of sensitive or important habitat, substantially interfere with existing or 

characteristics uses, result in damage to the ecosystem or adversely affect public health.

5. The discharge/receiving water mixture must not exceed water quality criteria outside 

the boundary of a mixing zone.

Ecology conducted a reasonable potential analysis, using procedures established by the EPA and 

by Ecology, for each pollutant (Appendix H). Ecology concluded the discharge/receiving water 

mixture will not violate water quality criteria outside the boundary of the mixing zone if permit 

limits are met.

6. The size of the mixing zone and the concentrations of the pollutants must be minimized.
Page 24

At any given time, the effluent plume uses only a portion of the acute and chronic mixing zone, 

which minimizes the volume of water involved in mixing. Because tidal currents change 

direction, the plume orientation within the mixing zone changes. The plume rises through the 

water column as it mixes therefore much of the receiving water volume at lower depths in the 

mixing zone is not mixed with discharge. Similarly, because the discharge may stop rising at 

some depth due to density stratification, waters above that depth will not mix with the discharge. 

Ecology determined it is impractical to specify in the permit the actual, much more limited 

volume in which the dilution occurs as the plume rises and moves with the current.

Ecology minimizes the size of mixing zones by requiring dischargers to install diffusers when 

they are appropriate to the discharge and the specific receiving waterbody. When a diffuser is 

installed the discharge and the receiving water is more completely mixed in a shorter time 

period. Ecology also minimizes the size of the mixing zone (in the form of the dilution factor) 

using design criteria with a low probability of occurrence. For example, Ecology uses the 

expected 95th percentile pollutant concentration, the 90th percentile background concentration, 

the centerline dilution factor and the lowest flow occurring once in every 10 years to perform the

reasonable potential analysis.

The facility continues to conduct pollution prevention activities and has completed pollution 

prevention projects. These activities also minimize the concentrations of pollutants in the 

discharge.

Because of the above reasons, Ecology has effectively minimized the size of the mixing zone 

authorized in the proposed permit.

7. Maximum size of mixing zone.

The authorized mixing zone for the discharge at Outfall 001 does not exceed the maximum size 

restriction.

8. Acute Mixing Zone.

• The discharge/receiving water mixture must comply with acute criteria as near to 

the point of discharge as practicably attainable.

Ecology determined that the acute criteria will be met at 10% of the distance (22.5 ft)

of the chronic mixing zone (225 ft).

• The pollutant concentration, duration and frequency of exposure to the 

discharge, will not create a barrier to migration or translocation of indigenous 

organisms to a degree that has the potential to cause damage to the ecosystem.

As described above, the toxicity of any pollutant depends upon the exposure, the 

pollutant concentration, and the time the organism is exposed to that concentration. 

Authorizing a limited acute mixing zone for this discharge assures that it will not 
Page 25

create a barrier to migration. The effluent from this discharge will rise as it enters the 

receiving water, assuring that the rising effluent will not cause translocation of 

indigenous organisms near the point of discharge (below the rising effluent).

Dilution modeling has demonstrated that mixing in the acute zone occurs very rapidly 

as the less dense effluent rises through the water column due to both the diffuser 

design and the buoyance of the effluent. The duration and frequency of exposure to 

elevated concentrations by any drifting or non-strong swimming organisms is 

minimized because the organisms simply cannot stay in one place while the plume 

moves past them. Because the mixing zone poses no barrier to organisms, strong 

swimming species are able to avoid the plume. Exposure to elevated concentrations in 

the effluent by benthic organisms is avoided because the plum rises in the water 

column.

The acute mixing zone is sized at 10% of the distance of the chronic mixing zone.

• Comply with size restrictions.

The mixing zone authorized for the discharge at Outfall 001 complies with the size 

restrictions published in Chapter 173-201A WAC.

9. Overlap of Mixing Zones.

The mixing zone for the discharge at Outfall 001 does not overlap another mixing zone.

D. Designated Uses and Surface Water Quality Criteria

Applicable designated uses and surface water quality criteria are defined in Chapter 173-201A 

WAC. In addition, the U.S. EPA set human health criteria for toxic pollutants (40 CFR 131.36). 

Criteria applicable to this facility’s discharge are summarized below.

Aquatic life uses are designated using the following general categories. All indigenous fish and 

non-fish aquatic species must be protected in waters of the state.

(a) Extraordinary quality - salmonid and other fish migration, rearing, and spawning; 

clam, oyster, and mussel rearing and spawning; crustaceans and other shellfish (crabs, 

shrimp, crayfish, scallops, etc.) rearing and spawning.

(b) Excellent quality - salmonid and other fish migration, rearing, and spawning; clam, 

oyster, and mussel rearing and spawning; crustaceans and other shellfish (crabs, shrimp, 

crayfish, scallops, etc.) rearing and spawning.

(c) Good quality - salmonid migration and rearing; other fish migration, rearing, and 

spawning; clam, oyster, and mussel rearing and spawning; crustaceans and other shellfish 

(crabs, shrimp, crayfish, scallops, etc.) rearing and spawning.

(d) Fair quality - salmonid and other fish migration.
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The aquatic life uses for this receiving water are identified below:

Table 8: Aquatic Life Uses & Associated Criteria

Excellent quality

Temperature Criteria – Highest 1D MAX 16o C (60.8o F)

Dissolved Oxygen Criteria – Lowest 1 Day 

Minimum

6.0 mg/L

Turbidity Criteria • 5 NTU over background when the 

background is 50 NTU or less; or 

• A 10 percent increase in turbidity when the

background turbidity is more than 50 NTU.

pH Criteria pH must be within the range of 7.0 to 8.5 with 

a human-caused variation within the above

range of less than 0.5 units.

To protect shellfish harvesting, fecal coliform organism levels must not exceed a geometric 

mean value of 14 colonies/100 mL, and not have more than 10 percent of all samples (or any 

single sample when less than ten sample points exist) obtained for calculating the geometric 

mean value exceeding 43 colonies/100 mL.

The miscellaneous marine water uses are wildlife habitat, harvesting, commerce and 

navigation, boating, and aesthetics.

E. Evaluation of Surface Water Quality -Based Effluent Limits for Numeric Criteria

Pollutants in an effluent may affect the aquatic environment near the point of discharge (near 

field) or at a considerable distance from the point of discharge (far field). Toxic pollutants, for 

example, are near-field pollutants--their adverse effects diminish rapidly with mixing in the 

receiving water. Conversely, a pollutant such as biological oxygen demand (BOD) is a far-field 

pollutant whose adverse effect occurs away from the discharge even after dilution has occurred. 

Thus, the method of calculating surface water quality-based effluent limits varies with the point 

at which the pollutant has its maximum effect.

Pollutant concentrations in the proposed discharge exceed water quality criteria despite using

technology-based controls which Ecology determined fulfills AKART. Ecology therefore 

authorizes a mixing zone in accordance with the geometric configuration, flow restriction, and 

other restrictions imposed on mixing zones described in chapter 173-201A WAC.

Diffuser Information 

The diffuser at Outfall 001 is 26 feet long with a diameter of 30 inches. There are 3 ports 12 

inches in diameter. The distance between ports is 11 feet. The port openings are rectangular 

shaped with a length of 12.8 inches and width of 6 inches. The port opening information was 

obtained from information contained in “Outfall and Diffuser Inspection” report dated 

September 20, 2010. The MLLW depth at the diffuser is 25 feet. This information is available in 

the Dilution Ratio Study prepared by CH2M HILL and submitted to Ecology in February of 

1991.
Page 27

Chronic Mixing Zone

WAC 173-201A-100(4)(b)(i) specifies mixing zones shall not extend in any horizontal direction 

from the discharge ports for a distance greater than 200 feet plus the depth of water over the 

discharge ports as measured during mean lower low water (MLLW). Given a MLLW water 

depth of 25 feet (7.6 meters) for Tesoro's outfall, the horizontal distance therefore is 225 feet 

(68.6 meters). The mixing zone extends from the seabed to the top of the water surface.

Acute Mixing Zone

WAC 173-201A-100(8)(b) specifies that in estuarine waters a zone where acute criteria may be 

exceeded shall not extend beyond 10% of the distance established for the maximum or chronic 

zone as measured independently from the discharge ports. The acute zone therefore extends 22.5 

feet (6.86 meters) from the discharge ports.

Dilution factors

Ecology used EPA’s Visual Plumes model UM3 to predict dilution factors at the edge of the 

mixing zones. The ambient characteristics used were similar to those used for the mixing zone 

analysis at the BP Cherry Point refinery. Ecology’s previous mixing zone analysis for Tesoro 

used DOS Plumes. UM3 is now fully three-dimensional compared to UM in DOS Plumes. So, 

some of the results may be slightly different.

To determine the acute dilution factor, Ecology used a 10 percentile ambient velocity of 1 cm/s 

from previous mixing zone analysis along with the updated current daily maximum flow of 7.78 

MGD and a daily maximum temperature of 31.7 C. These assumptions resulted in a dilution 

factor of 18 was obtained which is comparable to the previous dilution factor of 20. The 

difference is likely related to the slight increase in daily maximum flow.

To determine the chronic dilution factor, Ecology used a 50th percentile ambient velocity of 5.5 

cm/s from the previous mixing zone analysis along with the updated current monthly average 

flow of 4.5 MGD. The average pump-out rate for effluent discharge was estimated previously at

10,500 gpm which is equivalent to 15.12 MGD. The highest 30-day average flow (2006-2011) 

was estimated at 4.5 MGD. At a rate of 15.12 MGD, it would take 0.297 day to pump all the 

water. So the flow occurs for 29.7% of the day. The model predicted dilution factor of 31 was 

divided by this number (0.297) to get a near 100 dilution factor. The previous dilution factor was 

91.

For non-carcinogens the flow is the same as the chronic flow, so the dilution factor will be same. 

To determine the dilution factor for carcinogens the annual average flow (2.8 MGD) was used 

and the same procedure as in estimating the chronic dilution factor was followed. This produced 

a Human Health Carcinogen dilution factor of 166. This compares to the previous factor of 93.

Appendix I shows the input parameters and dilution factors.

WAC 173-201A-400-(6) requires the dilution zone to be minimized, and as such the most 

conservative of dilution results must used. In this case, with Ecology decided to retain the 

dilution factors from the previous permit, with the exception of the new acute dilution factor of 

18.
Page 28

Table 9: Dilution Factors (DF)

Acute Chronic

Aquatic Life 18 91

Human Health, Carcinogen N/A 93

Human Health, Non-carcinogen N/A 91

Ecology determined the impacts of immediate oxygen deficiency, temperature, pH, fecal 

coliform, chlorine, ammonia, metals, nutrients, and other toxics as described below, using the 

dilution factors in the above table. The derivation of surface water quality-based limits also 

takes into account the variability of pollutant concentrations in both the effluent and the 

receiving water.

BOD5

Ecology predicted no violation of the surface water quality standards for dissolved oxygen (DO)

under critical conditions. Therefore, Ecology placed the technology-based effluent limit for 

BOD5 in the permit.

Temperature

The state temperature standards (WAC 173-201A-200-210 and -600-612) include multiple 

elements:

• Annual summer maximum threshold criteria (June 15 to September 15)

• Supplemental spawning and rearing season criteria (September 15 to June15)

• Incremental warming restrictions

• Protections against acute effects

Ecology evaluates each criterion independently to determine reasonable potential and derive 

permit limits.

• Annual summer maximum and supplementary spawning/rearing criteria

Each water body has an annual maximum temperature criterion [WAC 173-201A-200(1) 

(c), 210(1)(c), and Table 602]. These threshold criteria (e.g., 12, 16, 17.5, 20°C) protect 

specific categories of aquatic life by controlling the effect of human actions on summer 

temperatures.

Some waters have an additional threshold criterion to protect the spawning and 

incubation of salmonids (9°C for char and 13°C for salmon and trout) [WAC 173-201A602, Table 602]. These criteria apply during specific date-windows.

The threshold criteria apply at the edge of the chronic mixing zone. Criteria for most 

fresh waters are expressed as the highest 7-Day average of daily maximum temperature 

(7-DADMax). The 7-DADMax temperature is the arithmetic average of seven 

consecutive measures of daily maximum temperatures. Criteria for marine waters and 
Page 29

some fresh waters are expressed as the highest 1-Day annual maximum temperature (1-

DMax).

• Incremental warming criteria

The water quality standards limit the amount of warming human sources can cause under 

specific situations [WAC 173-201A-200(1)(c)(i)-(ii), 210(1)(c)(i)-(ii)]. The incremental 

warming criteria apply at the edge of the chronic mixing zone.

At locations and times when background temperatures are cooler than the assigned 

threshold criterion, point sources are permitted to warm the water by only a defined 

increment. These increments are permitted only to the extent doing so does not cause 

temperatures to exceed either the annual maximum or supplemental spawning criteria.

At locations and times when a threshold criterion is being exceeded due to natural 

conditions, all human sources, considered cumulatively, must not warm the water more 

than 0.3°C above the naturally warm condition.

When Ecology has not yet completed a TMDL, our policy allows each point source to 

warm water at the edge of the chronic mixing zone by 0.3°C. This is true regardless of 

the background temperature and even if doing so would cause the temperature at the edge 

of a standard mixing zone to exceed the numeric threshold criteria. Allowing a 0.3°C 

warming for each point source is reasonable and protective where the dilution factor is 

based on 25% or less of the critical flow. This is because the fully mixed effect on 

temperature will only be a fraction of the 0.3°C cumulative allowance (0.075°C or less) 

for all human sources combined.

• Temperature Acute Effects

Instantaneous lethality to passing fish: The upper 99th percentile daily maximum 

effluent temperature must not exceed 33°C; unless a dilution analysis indicates ambient 

temperatures will not exceed 33°C 2-seconds after discharge.

General lethality and migration blockage: Measurable (0.3°C) increases in 

temperature at the edge of a chronic mixing zone are not allowed when the receiving 

water temperature exceeds either a 1DMax of 23°C or a 7DADMax of 22°C.

Lethality to incubating fish: Human actions must not cause a measurable (0.3°C) 

warming above 17.5°C at locations where eggs are incubating.

Annual summer maximum, supplementary spawning criterion, and incremental warming 

criteria: Ecology calculated the reasonable potential for the discharge to exceed the annual 

summer maximum, the supplementary spawning criterion, and the incremental warming criteria 

(see temperature calculation in Appendix J).

The discharge is only allowed to warm the water by a defined increment when the background 

(ambient) temperature is cooler or warmer than the assigned threshold criterion. Ecology allows 
Page 30

warming increments only when they do not cause temperatures to exceed either the annual 

maximum or supplemental spawning criteria.

The incremental increase for this discharge is within the allowable amount. Therefore, the 

proposed permit does not include a temperature limit.

The permit requires additional monitoring of effluent temperature. Ecology will reevaluate the 

reasonable potential during the next permit renewal.

General lethality and migration blockage: The receiving water conditions are listed in Section 

II.F of the fact sheet. The Strait of Georgia does not exceed a 1DMax of 23°C.

pH

Compliance with the technology-based limits of 6.0 to 9.0 will assure compliance with the water 

quality standards of surface waters because of the high buffering capacity of marine water.

Fecal Coliform

The permit requires the refinery to comply with domestic technology based effluent limits for 

fecal coliforms in their effluent, since domestic wastewater is treated in their wastewater facility. 

Domestic wastewater standards are established in Chapter 173-221 WAC, entitled "Discharge 

Standards and Effluent Limitations For Domestic Wastewater Facilities". Domestic effluent 

limits for fecal coliforms are 200 organisms/100 ml on a monthly average basis with a maximum 

of 400 organisms/100 ml in any one sample. Tesoro must meet the water quality standard for 

marine excellent receiving waters (14 organisms/100 ml) at the edge of the chronic zone. With a 

dilution of 91:1 at the edge of the chronic zone the predicted fecal coliform concentration at the 

boundary of the chronic mixing zone is 4.3 organisms/100 ml if the maximum technical 

concentration standard of 400 is met and there are no fecal coliforms present in the background 

receiving water. Ecology calculated this concentration using a simple mass balance equation as 

follows:

[0(91) + 400(1)]/92 = 4.3

The technological standard is therefore protective of the water quality standard.

Toxic Pollutants

Federal regulations (40 CFR 122.44) require Ecology to place limits in NPDES permits on toxic 

chemicals in an effluent whenever there is a reasonable potential for those chemicals to exceed 

the surface water quality criteria. Ecology does not exempt facilities with technology-based 

effluent limits from meeting the surface water quality standards.

Ecology determined through review of available data and knowledge of the refinery process that 

the following toxic pollutants are present in the discharge: cyanide, sulfide, copper, zinc, lead, 

silver, chloroform, dichlorobromomethane, antimony, arsenic, mercury, nickel, thallium, nitrate, 

phosphorus, chromium, phenol, selenium, chlorine and ammonia. Ecology conducted a 

reasonable potential to exceed analysis (see Appendix H) on these parameters to determine 

whether it would require effluent limits in this permit.

Ecology conducted the reasonable potential to exceed analysis using receiving water and waste 

discharge conditions that represent the critical condition. Ecology obtained the receiving water 
Page 31

background data for the metal parameters from a study undertaken by the Western States 

Petroleum Association (WSPA) in 1997. The study included 10 samples taken at three different 

locations within Puget Sound in an effort to provide representative information about the 

receiving water outside the influence of the refineries. The sampling period chosen represents 

the critical period in the receiving water. The results of this study are documented in the 

February 1998 report entitled Background Metals Concentrations in Selected Puget Sound 

Marine Receiving Waters. There are limited effluent data available for metals. Ecology 

obtained effluent values from the permit application and its inspection data.

Valid ambient background data were available for ammonia, total cyanide, fluoride, aluminum, 

dissolved cadmium, dissolved copper, dissolved lead, mercury, and dissolved zinc. Calculations 

using all applicable data resulted in a determination that there is no reasonable potential for this 

discharge to cause a violation of water quality standards (see Appendix H). This determination 

assumes that the refinery meets the other effluent limits of this permit.

Sodium hypochlorite is introduced at the final stages of waste water treatment to reduce any 

fecal coliform in the effluent. A water quality based effluent limit for chlorine was included in 

the previous permit. Again, calculations using the maximum discharge amount, showed that 

there is no reasonable potential for this discharge to cause a violation of water quality standards

for chlorine. Therefore no chlorine limit is required.

Water quality criteria for most metals published in chapter 173-201A WAC are based on the 

dissolved fraction of the metal (see footnotes to table WAC 173-201A-240(3); 2006). Tesoro

may provide data clearly demonstrating the seasonal partitioning of the dissolved metal in the 

ambient water in relation to an effluent discharge. Ecology may adjust metals criteria on a sitespecific basis when data is available clearly demonstrating the seasonal partitioning in the 

ambient water in relation to an effluent discharge.

Ammonia

Ammonia is considered a toxic pollutant and Ecology evaluated it for reasonable potential to 

exceed water quality standards. Ammonia's toxicity depends on what portion is available in the 

unionized form. The amount of unionized ammonia depends on the pH, salinity, and 

temperature of the receiving marine water. Ecology must use receiving water information to 

evaluate ammonia toxicity.

Ecology evaluated one ambient receiving water station, GRG002, to determine the site specific 

acute and chronic criteria and to obtain background ammonia data. Located in the Straits of 

Georgia near Patos Island, GRG002 is a long term core station for which substantial data exists, 

and which adequately represents the receiving water environment near Tesoro’s outfall. Using 

Hampson's model in a spreadsheet form, Ecology calculated the acute and chronic ammonia 

criteria. From those criteria, Ecology used the 90th percentile value to represent the critical 

condition as recommended by the Ecology Permit Writer's Manual. It used the values for the 

ambient station and the 90th percentile values for background total ammonia concentration in the 

reasonable potential calculation shown in Appendix H. With the available dilution at Tesoro, 

Ecology determined no reasonable potential to exceed water quality standards for ammonia at 

the edge of the acute and chronic dilution zones.
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Stormwater Outfalls 002-004

Much of the stormwater from Tesoro runs off from lands not significantly exposed to industrial 

activities or materials and with little impermeable surfaces. At times of the year, most of the 

stormwater percolates into the ground and is not discharged offsite. As discussed previously, it 

is a very rare occurrence to have stormwater discharged at outfalls 002-004.

F. Whole Effluent Toxicity

The water quality standards for surface waters forbid discharge of effluent that causes toxic 

effects in the receiving waters. Many toxic pollutants cannot be measured by commonly 

available detection methods. However, laboratory tests can measure toxicity directly, by 

exposing living organisms to the wastewater and measuring their responses. These tests measure 

the aggregate toxicity of the whole effluent, so this approach is called whole effluent toxicity 

(WET) testing. Some WET tests measure acute toxicity and other WET tests measure chronic 

toxicity.

• Acute toxicity tests measure mortality as the significant response to the toxicity of the 

effluent. Dischargers who monitor their wastewater with acute toxicity tests find early 

indications of any potential lethal effect of the effluent on organisms in the receiving 

water.

• Chronic toxicity tests measure various sublethal toxic responses such as retarded growth 

or reduced reproduction. Chronic toxicity tests often involve either a complete life cycle 

test on an organism with an extremely short life cycle, or a partial life cycle test during a 

critical stage of a test organism's life. Some chronic toxicity tests also measure organism 

survival.

Ecology-accredited WET testing laboratories use the proper WET testing protocols, fulfill the 

data requirements, and submit results in the correct reporting format. Accredited laboratory staff 

know about WET testing and how to calculate an NOEC, LC50, EC50, IC25, etc. Ecology gives 

all accredited labs the most recent version of Ecology Publication # WQ-R-95-80, Laboratory 

Guidance and Whole Effluent Toxicity Test Review Criteria

(http://www.ecy.wa.gov/biblio/9580.html), which is referenced in the permit. Ecology 

recommends that the Permittee sends a copy of the acute or chronic toxicity sections(s) of its 

NPDES permit to the laboratory.

Acute Toxicity

WET testing conducted during the previous permit term showed the facility’s effluent has a 

reasonable potential to cause acute toxicity in the receiving water. The proposed permit will 

include an acute toxicity limit. The effluent limit for acute toxicity is: No acute toxicity 

detected in a test sample representing the acute critical effluent concentration (ACEC).

The acute critical effluent concentration (ACEC) is the concentration of effluent at the boundary 

of the acute mixing zone during critical conditions. The ACEC equals 5 % effluent.

Compliance with an acute toxicity limit is measured by an acute toxicity test comparing test 

organism survival in the ACEC (using a sample of effluent diluted to equal the ACEC) to 

survival in nontoxic control water. Tesoro is in compliance with the acute toxicity limit if there 
Page 33

is no statistically significant difference in test organism survival between the ACEC sample and 

the control sample.

Chronic Toxicity

As required in the existing permit, the Permittee conducted chronic toxicity testing on the final 

effluent during the third or fourth year of the permit term. The two organisms tested were top 

smelt and blue mussel. Results of the chronic testing in Appendix K showed no reasonable 

potential for effluent discharges to cause receiving water toxicity. The proposed permit does not 

include a chronic WET limit. Tesoro must retest the effluent before submitting an application 

for permit renewal in order to demonstrate that chronic toxicity has not increased in the effluent. 

In addition:

• If Tesoro makes process or material changes which, in Ecology's opinion, increase the 

potential for effluent toxicity, then Ecology may (in a regulatory order, by permit 

modification, or in the permit renewal) require the facility to conduct additional effluent 

characterization.

• If WET testing conducted for submittal with a permit application fails to meet the 

performance standards in WAC 173-205-020, Ecology will assume that effluent toxicity 

has increased. Tesoro may demonstrate to Ecology that effluent toxicity has not 

increased by performing additional WET testing after it has made the process or material 

changes.

PACIFIC HERRING

The 2008 Washington State Herring Stock Status Report published by the Washington Department 

of Fish and Wildlife (WDFW) in November 2009 notes that the spawning biomass for the Fidalgo 

Bay Pacific herring (Clupea pallasi) stock has declined significantly since 1999. WDFW also 

considers the status of the North Puget Sound region herring stocks in general to be depressed. 

Less than half of all Puget Sound herring stocks were listed by WDFW in the 2008 report as 

healthy or moderately healthy.

The Cherry Point herring stock, which spawns in late spring just north of Bellingham, was once 

as large as all of the other herring stocks in Washington combined. The stock has dramatically 

declined to 7.5% of its size in 1973. The Cherry Point stock size declined from nearly 15,000 

tons in 1973 to only 1120 tons in 2012. Although much of the decline may be due to natural 

factors, point and non-point sources of pollution potentially may be acting in concert with the 

natural stressors.

Because of the large amount of industrial activity at Cherry Point and Fidalgo Bay associated 

with refineries and other heavy industry, Ecology and Western Washington University developed 

and validated herring toxicity tests to use for effluent and environmental testing. In November 

2005, Ecology announced the validation for regulatory use of a 96-hour herring prolarval acute 

survival test and a 10-day herring embryo survival and normal development test. The validation 

of the 7-day larval herring survival and growth test was announced in a final report dated 

November 2011 and updated in September 2012 to add another lab.
Page 34

In April 2006, Ecology issued an agreed order to the BP Cherry Point Refinery, ConocoPhillips 

Ferndale Refinery, Shell Puget Sound Refinery, Tesoro Anacortes Refinery, and the Alcoa-Intalco 

Works Aluminum Smelter requiring them to conduct prolarval herring acute survival tests twice 

annually at each of their process wastewater outfalls. The order included a requirement to follow 

up on any adverse effects found during the course of these studies with additional testing and/or 

investigation. Ecology defined adverse effects as the Lowest Observable Effects Concentration 

(LOEC) being equal to or lower than the Acute Critical Effluent Concentration (ACEC).

The agreed order stated that if the LOEC was equal to or lower than the ACEC, Tesoro must 

develop and implement a Toxicity Identification/Reduction Evaluation (TI/RE) Plan. The order 

also stated that with prior approval from Ecology, Tesoro could use the topsmelt Atherinops 

affinis, 96-hour acute survival test as an alternate test if herring larvae are unavailable during the 

test window.

From 2007 to 2012, the herring tests run on Tesoro’s effluent showed some toxicity on three 

occasions, but the results did not trigger additional testing or investigation. In several cases, 

Tesoro was unable to obtain herring larvae during the test window and Ecology approved the use 

of the topsmelt test as a substitute.

The results of the prolarval herring acute testing and topsmelt testing for Tesoro are summarized in 

Appendix K.

Herring toxicity testing is included in the proposed permit. Tesoro is required to conduct acute 

testing using the prolarval 4-day survival test and chronic testing using the embryo survival and 

normal development test and the larval 7-day survival and growth test. The permit requires that 

effluent monitoring be done with both herring and standard EPA toxicity tests. This testing is 

not for compliance monitoring or effluent characterization so the requirements of WAC 173-205-

050(1)(d) do not apply.

The permit requires a toxicity investigation if testing shows any adverse effects. The EPA tests 

can be used to investigate the cause of any significant toxicity and the findings of the 

investigation can be confirmed with the herring tests.

Another goal in pairing the herring tests with EPA tests is to discover the extent to which EPA 

tests can be used to protect herring. Herring are unavailable for testing outside of the six-month 

West Coast herring spawning season. Effectively monitoring effluents and controlling toxicity 

requires more frequent testing than is possible using test organisms obtained from the spawning 

of wild herring. The standard EPA toxicity tests are available all year and can be set up quickly 

if needed. The permit requirements seek to establish the relative sensitivity of herring tests and 

analogous EPA tests and to examine the responses of both tests to effluent constituents known to 

be toxic. If successful, future permit fact sheets may define the relative toxicity of the EPA and 

herring tests and describe how the permit requires EPA tests to specifically protect herring. The 

EPA tests would replace herring testing in permits.
Page 35

G. Human Health

Washington’s water quality standards include 91 numeric human health-based criteria that 

Ecology must consider when writing NPDES permits. These criteria were established in 1992 

by the U.S. EPA in its National Toxics Rule (40 CFR 131.36). The National Toxics Rule allows 

states to use mixing zones to evaluate whether discharges comply with human health criteria.

Ecology determined that Tesoro’s effluent may contain chemicals of concern posing a risk to 

human health. Ecology determined this because data or process information indicate regulated 

chemicals occur in the discharge.

Ecology conducted a determination of the discharge's potential to violate the water quality 

standards as required by 40 CFR 122.44(d) by following the procedures published in the 

Technical Support Document for Water Quality-Based Toxics Control (EPA/505/2-90-001) and 

Ecology's Permit Writer's Manual (Ecology Publication 92-109, July, 2006) to make this 

reasonable potential determination.

Tesoro submitted effluent characterization data for evaluating human health criteria as part of 

their permit renewal application received on November 3, 2010. Reasonable potential to exceed 

human health criteria is evaluated for each parameter in Appendix H. Ecology’s evaluation 

showed that the discharge has no reasonable potential to cause a violation of water quality 

standards, thus effluent limits are not warranted.

Arsenic

In 1992, the USEPA adopted risk-based arsenic criteria for the protection of human health for the 

State of Washington. The criterion for marine waters is 0.14 μg/L inorganic arsenic and is based 

on exposure from fish and shellfish tissue ingestion. The freshwater criterion is 0.018 μg/L and 

is based on exposure from fish and shellfish tissue and water ingestion. These criteria have 

caused confusion in implementation because they differ from the drinking water maximum 

contaminant level (MCL) of 10 μg/L, which is not risk-based, and because the human health 

criteria are sometimes exceeded by natural background concentrations of arsenic in surface water 

and ground water.

In Washington, when a natural background concentration exceeds the criterion, the natural 

background concentration becomes the criterion, and no dilution zone is allowed. This could 

result in a situation where natural groundwater or surface water used as a municipal or industrial 

source-water would need additional treatment to meet numeric effluent limits even though no 

arsenic was added as waste. Although this is not the case for all dischargers, Ecology does not 

have data at this time to quantify the extent of the problem.

A regulatory mechanism to deal with the issues associated with natural background 

concentrations of arsenic in groundwater-derived drinking waters is currently lacking. 

Consequently, the Water Quality Program, at this time, has decided to use a three-pronged 

strategy to address the issues associated with the arsenic criteria. The three strategy elements 

are:
Page 36

1. Pursue, at the national level, a solution to the regulatory issue of groundwater sources 

with high arsenic concentrations causing municipal treatment plant effluent to exceed 

criteria. The revision of the drinking water MCL for arsenic offered a national opportunity to 

discuss how drinking water sources can affect NPDES wastewater dischargers, however Ecology 

was unsuccessful in focusing the discussion on developing a national policy for arsenic 

regulation that acknowledges the risks and costs associated with management of the public 

exposure to natural background concentrations of arsenic through water sources. The current 

arsenic MCL of 10 μg/L could also result in municipal treatment plants being unable to meet 

criteria-based effluent limits. Ecology will continue to pursue this issue as opportunities arise.

2. Additional and more focused data collection. The Water Quality Program will in some 

cases require additional and more focused arsenic data collection, will encourage or require 

dischargers to test for source water arsenic concentrations, and will pursue development of a 

proposal to have Ecology's Environmental Assessment Program conduct drinking water source 

monitoring as well as some additional ambient monitoring data. At this time, Washington 

NPDES permits will contain numeric effluent limits for arsenic based only on treatment 

technology and aquatic life protection as appropriate.

3. Data sharing. Ecology will share data with USEPA as they work to develop new risk-based 

criteria for arsenic and as they develop a strategy to regulate arsenic.

Dioxin

EPA traced the dioxins found in some refinery effluents to an internal waste stream from the 

regeneration of catalytic reformer units. Tesoro has a catalytic reforming unit, which regenerates

sporadically in frequency and duration. Tesoro has not detected dioxin in its final effluent, but 

even if present, it would be difficult to detect due to dilution with other process wastewaters 

prior to entering the wastewater treatment plant and the intermittent generation of the caustic 

wash water from the reformers.

Ecology has determined that further investigation into the generation of dioxins at refineries is 

necessary. The previous permit required Tesoro to monitor the dioxin and furan in the 

regeneration wastewater stream, in the API separator sludge, and in the final effluent captured at 

the time that is most likely to contain wastewater generated during the catalytic reformer 

regenerated events. The analysis included chlorinated dioxins and furans (2,3,7,8-Cl substituted 

tetra- through octa- congeners). The permit specified the test method and the required detection 

level.

Tesoro also investigated the fate of any dioxins and furans. Literature has shown that dioxins 

tend to bind to particulate matter in the wastewater, much of which settles out in the API 

separators.

Tesoro’s Dioxin Study Report submitted to Ecology on March 12, 2009 indicated that 2,3,7,8 

TCDD was detected in 3 samples (Reformer spent caustic wash water – April, May, and 

December 2008). The measured concentrations were 103, 59.1, and 45.3 ppq respectively.

The proposed permit requires Tesoro to sample the final effluent (Outfall 001) and the upstream 

wastewater stream from the catalytic reformer unit for chlorinated dioxin and furan (2,3,7,8-Cl 

substituted tetra- through octa- congeners) concentrations twice during the next permit cycle.
Page 37

H. Sediment Quality

The aquatic sediment standards (WAC 173-204) protect aquatic biota and human health. Under 

these standards Ecology may require a facility to evaluate the potential for its discharge to cause 

a violation of sediment standards (WAC 173-204-400). You can obtain additional information 

about sediments at the Aquatic Lands Cleanup Unit website. 

http://www.ecy.wa.gov/programs/tcp/smu/sediment.html

In 2001, Tesoro conducted a marine sediment sampling and analysis study. The purpose of the 

study was to comply with the NPDES permit sediment monitoring requirements.

Ecology’s review of the sediment surveys in 1995 and 2001 showed no violation of sediment 

standards. There was a concern that more study of possible ammonia impacts may be needed in 

the future.

The proposed permit requires a sediment toxicity analysis of samples collected from the top 10 

cm of sediment in the vicinity of the outfall. This sediment monitoring is required to be 

conducted at the beginning of the proposed permit cycle, which is approximately 12 years after 

the 2001 sediment sampling event.

Tesoro must collect enough sediment so that it can analyze conventional sediment parameters, 

conduct bioassays, and if necessary, analyze chemistry. Samples showing biological 

exceedances will be required to undergo chemical analysis.

I. Ground Water Quality

The Ground Water Quality Standards, (Chapter 173-200 WAC), protect beneficial uses of 

ground water. Permits issued by Ecology must not allow violations of those standards (WAC 

173-200-100).

Tesoro has one unlined holding pond (Tank 165 yard), used intermittently to temporarily store 

final effluent, that could potentially discharge to groundwater. This pond is located within -

approximately 100 feet of Padilla Bay at high tide. If a discharge to ground water from this pond 

is occurring, it discharges almost directly into the Bay, where the final effluent is currently 

discharged via a marine outfall. The discharge would consist of high quality wastewater, treated 

to secondary treatment levels. Concentrations of most pollutants in Tesoro’s effluent were found 

to be less than the groundwater quality criteria. Only three metals, mercury, selenium, and 

arsenic, and the organic compound chloroform exceeded the criteria. Chloroform and arsenic 

were the only parameters present at levels that were significantly higher than the criteria. 

Incidental leakage of effluent of this quality, and in this location, should have undetectable or 

minimal impacts to ground water quality. The volume of groundwater which would potentially 

be impacted would be very small and impacts would occur just prior to its entering the marine 

receiving water (the current discharge location). Therefore no limitations or actions are required 

based on potential effects to ground water.

Table 10 compares the calculated effluent limits with the limits from the previous permit issued 

in April, 2006.
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Table 10: Comparison of Effluent Limits with Previous Permit

Units Basis of 

Limit

Previous Permit 2006 

Effluent Limits: Outfall 001 

Calculated 

Effluent Limits: 

Outfall 001 

Parameter Average 

Monthly

Maximum 

Daily

Average 

Monthly

Maximum 

Daily

Biochemical Oxygen 

Demand (5-day) lbs/day BPT 710 1280 800 1450

Chemical Oxygen Demand lbs/day BPT 4900 9500 5510 10710

Total Suspended Solids lbs/day BPT 560 890 640 1010

Oil and Grease lbs/day BPT 210 380 230 440

Oil and Grease mg/l

The concentration of oil and grease in the discharge 

must at no time exceed 15 mg/l and must not exceed 10 

mg/l more than three days per month.

Phenolic Compounds lbs/day

BPT & 

BAT 4.6 9.5 5.2 10.8

Ammonia as N lbs/day BPT 450 1010 540 1200

Sulfide lbs/day BPT 3.8 8.4 4.6 9.5

Hexavalent Chromium mg/l and 

lbs/day BPJ -- 0.050 --

0.050 mg/l 

and 1.52 

lbs/day

Fecal Coliforms

Organisms/

100mls 200 400 200 400

pH In the range of 6.0 to 9.0

IV. MONITORING REQUIREMENTS 

Ecology requires monitoring, recording, and reporting (WAC 173-220-210 and 40 CFR 122.41) 

to verify that the treatment process is functioning correctly and that the discharge complies with 

the permit’s effluent limits.

The monitoring schedule is detailed in the proposed permit under Condition S.2. Specified 

monitoring frequencies take into account the quantity and variability of the discharge, the 

treatment method, past compliance, significance of pollutants, and cost of monitoring.

The proposed permit requires Tesoro to collect and report information in the monthly DMR 

about parameters that do not have limits established in the permit. Ecology needs data on crude 

feedstock rates to evaluate technical discharge limits in the next permit. It needs the ballast 

water flow rate and total flow rate to determine the wasteload allocation for several parameters. 

It used rainfall data to determine if the refinery can use the stormwater allocation. Ecology will 

use the temperature data to evaluate compliance with water quality standards in the receiving 

water. The proposed permit also requires priority pollutant testing and dioxin testing for 

evaluation at the next permit renewal.
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A. Lab Accreditation

With the exception of certain parameters, the permit requires all monitoring data to be prepared 

by a laboratory registered or accredited under the provisions of Chapter 173-50 WAC, 

Accreditation of Environmental Laboratories. The Tesoro laboratory is currently accredited for:

• Biochemical Oxygen Demand (BOD5)

• Chemical Oxygen Demand (COD)

• Total Suspended Solids (TSS)

• Phenols, Total

• pH

• Sulfide (S)

• Ammonia (N)

• Oil and Grease (O&G)

B. Performance-Based Reduction of Monitoring Frequencies

EPA published guidance in April of 1996 entitled, “Interim Guidance For Performance-Based 

Reduction of NPDES Permit Monitoring Frequencies”. EPA’s goal is to reduce the regulatory 

burden associated with reporting and monitoring on the basis of excellent performance. The 

guidance provides a tool to evaluate the facility’s performance.

Ecology used this guidance to evaluate several parameters in Tesoro’s treated effluent. In 

addition to the approach recommended in the guidance, Ecology compared maximum values 

with permit limits. See Appendix L for the summary and evaluation of monitoring data.

For the parameters evaluated, Tesoro’s monitoring history has demonstrated an ability to 

consistently comply with regulatory limits. Ecology based the proposed monitoring frequencies 

on the guidance recommendations and best professional judgment.

Ecology increased the current monitoring frequencies for TSS, O&G, and sulfide. In some cases

EPA’s policy would have allowed less frequent monitoring. TSS and O&G are good indicators 

of when there is an upset condition at the wastewater treatment facility. Ecology maintained the 

monitoring frequencies for phenols and ammonia and reduced the monitoring frequencies for 

BOD and COD. Ecology uses best professional judgment to determine a reduced monitoring 

frequency to reward Tesoro’s good performance but also provide enough data to monitor the 

health of the wastewater treatment process. Tesoro must maintain good performance levels to 

continue to receive the reduced monitoring frequencies. If the facility’s performance levels 

deteriorate, Ecology can revert to the previous monitoring requirements.
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V. OTHER PERMIT CONDITIONS

A. Priority Pollutant Testing

Tesoro is required to sample the effluent from Outfall 001 annually and analyze the sample for 

priority pollutants. Tesoro must submit the results of the analysis to Ecology within 60 days of 

each sampling event.

B. Reporting and Recordkeeping

Ecology based permit condition S3 on our authority to specify any appropriate reporting and 

recordkeeping requirements to prevent and control waste discharges (WAC 173-220-210).

C. Operation and Maintenance Plan

Ecology requires industries to take all reasonable steps to properly operate and maintain their 

wastewater treatment system in accordance with state and federal regulations [40 CFR 122.41(e) 

and WAC 173-220-150(1)(g)]. Tesoro has prepared and submitted an operation and 

maintenance plan. Implementation of the procedures in the operation and maintenance plan 

ensures the facility’s compliance with the terms and limits in the permit.

D. Non-Routine and Unanticipated Discharges

Tesoro occasionally generates wastewater, which was not characterized in the permit application 

because it is not a routine discharge and was not anticipated at the time of the application. This 

wastewater typically consists of water used to pressure test petroleum storage tanks or fire water 

systems.

When Tesoro reconditions petroleum storage tanks, it thoroughly cleans and inspects them. The 

final step in the inspection is the hydrotest, which consists of filling the tank with clean water 

and monitoring the water level in the tank over time to see if any leakage has occurred. 

Discharging the hydrotest water to the wastewater treatment system reduces the efficiency of the 

treatment since the clean water dilutes the process water. Tesoro also tests its fire water system.

Tesoro may request to discharge this wastewater through outfalls 001, 002, 003, or 004.

The permit authorizes non-routine and unanticipated discharges under certain conditions. The 

refinery must characterize these wastewaters and examine any opportunities for reuse. The 

wastewater must meet the applicable water quality standards for the receiving water.

E. Wastewater Treatment Efficiency Study and Updated Engineering Report

Tesoro submitted the results of an updated treatment efficiency study and an engineering report 

for the wastewater treatment system to Ecology on October 19, 2010. Ecology approved the 

original engineering report submitted on April 28, 2000.
Page 41

The refinery’s biological system is operating at approximately 35% of its organic (as BOD5) 

treatment capacity and 60% to 70% of its hydraulic loading capacity.

Ecology will require a new wastewater treatment efficiency study if Tesoro proposes substantial 

alterations to the refinery that could cause a material change in the quantity or composition of the 

influent processed by the wastewater treatment system. In the event Ecology requires the study, 

Tesoro must submit a wastewater treatment study plan for Ecology approval. Tesoro must also 

update its engineering report to compare the new conditions with the predicted design capacity.

F. Pollution Prevention Plan

The previous NPDES permit required Tesoro to submit a Pollution Prevention Plan to identify 

opportunities to prevent, reduce, eliminate, or control releases of pollutants to influent 

wastewater streams, stormwater, and other waters of the state. The permit required Tesoro to 

implement opportunities that were technically and economically feasible. The NPDES Pollution 

Prevention Plan incorporated previous NPDES permit requirements for a spill plan, solid waste

handling and disposal plan, and a stormwater pollution prevention plan.

The following are projects completed by Tesoro during the last permit cycle that had a positive 

impact on wastewater treatment plant operations and provide protection to the receiving waters:

• New Amine Unit – The benefit is improved effluent plant reliability and increased 

effluent plant efficiency.

• Automated Crude Tank Dewatering System – These were installed on crude oil tanks 

3, 4, 5, and 60. This increases effluent plant treatment efficiency by reducing oil and 

grease loading at the bioreactor.

• Final Clarifier Skimmer – The new west skimmer increases effluent plant treatment 

efficiency.

• Trapman System – an integrated ultrasonic and temperature measurement system used 

to evaluate stream traps. This saves increased amounts of warm condensate that in turn 

can reduce the TSS in the effluent.

• Pollution Prevention Training – The training re-emphasizes environmental awareness 

which is essential to the success of the pollution prevention program. Refinery staff and 

managers are required to complete the training.

The proposed permit includes a pollution prevention requirement to follow-up on the work done 

by the refinery in the previous permit cycle. It includes a requirement to: 

• Continue to follow and update BMPs, SOPs, and other work practices to prevent or 

minimize the release of pollutants to the wastewater treatment system, stormwater, and 

waters of the state.

• Submit an update to the current NPDES Pollution Prevention Plan.
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• Submit a biennial evaluation of the Pollution Prevention Plan.

• Conduct stormwater inspections to ensure the adequacy of BMPs and to identify any 

unknown improper discharges to stormwater.

• Continue to identify and evaluate pollution prevention opportunities in all decisions 

having environmental consequences.

G. Dangerous Wastes – Permit by Rule Requirements

The proposed permit authorizes Tesoro to treat dangerous wastes generated on or off-site at the 

wastewater treatment facility, under the permit-by-rule provisions of WAC 173-303-802(5). 

This authorization is limited to the on-site and off-site waste streams identified and characterized 

in the NPDES permit application and in application amendments approved by Ecology. Wastes 

received from off-site include ballast water and retail distribution water. Ecology determined 

that the waste streams from off-site are similar in nature to those generated on-site and concluded

that Tesoro’s wastewater treatment facility should effectively treat them.

Effluent sampling and monitoring requirements established in the permit should adequately 

address the pollutants in these wastestreams. Permit-by-rule provisions cover the identified 

waste streams as long as the refinery complies with the conditions of the NPDES permit and with 

the dangerous waste requirements in WAC 173-303 pertaining to:

• Notification and identification numbers

• Designation of dangerous wastes

• Performance standards

• General waste analysis

• Security 

• Contingency plans and emergency procedures

• Emergencies 

• Manifest system 

• Operating record

• Facility reporting

H. Outfall Evaluation

Tesoro conducted an Outfall Evaluation in the summer of 2010 and submitted the report on

September 20, 2010. The purpose of the evaluation was to determine the condition of the 

discharge pipe and diffusers and to determine the extent of sediment accumulation in the 

outfall’s vicinity. Tesoro reported that the outfall line and diffuser were in good condition and 

functioning properly.

Condition S.18 in the proposed permit requires Tesoro to conduct another outfall inspection 

during the next permit term and submit a report detailing the findings of that inspection.
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I. Certified Operator

The refinery generates approximately 10,000 gallons of domestic wastewater per day. The 

domestic wastewater is commingled with process wastewater and treated in the refinery’s 

wastewater treatment system. Per WAC 173-230-140, Ecology requires the refinery’s operator in 

responsible charge of the day-to-day operation of the wastewater treatment plant to be certified 

for at least a Class II plant by the State of Washington.

J. General Conditions

Ecology bases the standardized General Conditions on state and federal law and regulations. 

They are included in all individual industrial NPDES permits issued by Ecology.

VI. PERMIT ISSUANCE PROCEDURES

A. Permit Modifications

Ecology may modify this permit to impose numerical limits, if necessary to comply with water 

quality standards for surface waters, with sediment quality standards, or with water quality 

standards for ground waters, after obtaining new information from sources such as inspections, 

effluent monitoring, outfall studies, and effluent mixing studies.

Ecology may also modify this permit to comply with new or amended state or federal 

regulations.

B. Proposed Permit Issuance

The proposed permit includes all statutory requirements for Ecology to authorize a wastewater 

discharge. The permit includes limits and conditions to protect human health and aquatic life, 

and the beneficial uses of waters of the State of Washington. Ecology proposes to issue this 

permit for a term of 5 years.

VII. REFERENCES FOR TEXT AND APPENDICES

Environmental Protection Agency (EPA) 

1991. Technical Support Document for Water Quality-based Toxics Control. EPA/505/2-

90-001.

1985. Water Quality Assessment: A Screening Procedure for Toxic and Conventional 

Pollutants in Surface and Ground Water. EPA/600/6-85/002a.

1983. Water Quality Standards Handbook. USEPA Office of Water, Washington, D.C.

Washington State Department of Ecology.
Page 44

1994. Permit Writer’s Manual. Publication Number 92-109 

Washington State Department of Ecology. 

2007. Focus Sheet on Solid Waste Control Plan, Developing a Solid Waste Control Plan 

for Industrial Wastewater Discharge Permittees. Publication Number 07-10-024

Washington State Department of Ecology.

Laws and Regulations( http://www.ecy.wa.gov/laws-rules/index.html)

Permit and Wastewater Related Information 

(http://www.ecy.wa.gov/programs/wq/wastewater/index.html)
Page 45

APPENDIX A - PUBLIC INVOLVEMENT INFORMATION

Ecology proposes to reissue a NPDES permit to the Tesoro Refining-Anacortes. The permit 

prescribes operating conditions and wastewater discharge limits. This fact sheet describes the 

facility and Ecology’s reasons for requiring permit conditions.

Ecology will place a Public Notice on May 29, 2013 in the Skagit Valley Herald/Anacortes 

American to inform the public and to invite comment on the proposed issuance of this National 

Pollutant Discharge Elimination System permit as drafted.

The Notice –

• Tells where copies of the draft Permit and Fact Sheet are available for public evaluation

(a local public library, the closest Regional or Field Office, posted on our website.).

• Offers to provide the documents in an alternate format to accommodate special needs.

• Asks people to tell us how well the proposed permit would protect the receiving water.

• Invites people to suggest fairer conditions, limits, and requirements for the permit.

• Invites comments on Ecology’s determination of compliance with antidegradation rules.

• Urges people to submit their comments, in writing, before the end of the comment period

• Tells how to request a public hearing about the proposed NPDES Permit.

• Explains the next step(s) in the permitting process.

Ecology has published a document entitled Frequently Asked Questions about Effective 

Public Commenting which is available on our website at 

http://www.ecy.wa.gov/biblio/0307023.html.

You may obtain further information from Ecology by telephone, (360) 407-6945 or by writing to 

the permit writer at the address listed below.

J. Mark Dirkx, P.E.

Department of Ecology

Industrial Section

PO Box 47600

Olympia, WA 98504-7600

The primary author of this permit and fact sheet is J. Mark Dirkx.
Page 46

APPENDIX B - GLOSSARY

1-DMax or 1-day maximum temperature: The highest water temperature reached on any given 

day. This measure can be obtained using calibrated maximum/minimum thermometers or 

continuous monitoring probes having sampling intervals of thirty minutes or less.

7-DADMax or 7-day average of the daily maximum temperatures: The arithmetic average of 

seven consecutive measures of daily maximum temperatures. The 7-DADMax for any 

individual day is calculated by averaging that day's daily maximum temperature with the 

daily maximum temperatures of the three days prior and the three days after that date.

Acute Toxicity: The lethal effect of a compound on an organism that occurs in a short period of 

time, usually 48 to 96 hours.

AKART: The acronym for “all known, available, and reasonable methods of prevention, control 

and treatment.” AKART is a technology-based approach to limiting pollutants from 

wastewater discharges which requires an engineering judgment and an economic judgment. 

AKART must be applied to all wastes and contaminants prior to entry into waters of the state 

in accordance with RCW 90.48.010 and 520, WAC 173-200-030(2)(c)(ii), and WAC 173-

216-110(1)(a).

Ambient Water Quality: The existing environmental condition of the water in a receiving water 

body.

Ammonia: Ammonia is produced by the breakdown of nitrogenous materials in wastewater. 

Ammonia is toxic to aquatic organisms, exerts an oxygen demand, and contributes to 

eutrophication. It also increases the amount of chlorine needed to disinfect wastewater.

Annual Average Design Flow (AADF): The average of the daily flow volumes anticipated to 

occur over a calendar year.

Average Monthly Discharge Limit: The average of the measured values obtained over a 

calendar month's time.

Best Management Practices (BMPs): Schedules of activities, prohibitions of practices, 

maintenance procedures, and other physical, structural and/or managerial practices to prevent 

or reduce the pollution of waters of the State. BMPs include treatment systems, operating 

procedures, and practices to control: plant site runoff, spillage or leaks, sludge or waste 

disposal, or drainage from raw material storage. BMPs may be further categorized as 

operational, source control, erosion and sediment control, and treatment BMPs.

BOD5: Determining the Biochemical Oxygen Demand of an effluent is an indirect way of 

measuring the quantity of organic material present in an effluent that is utilized by bacteria. 

The BOD5 is used in modeling to measure the reduction of dissolved oxygen in receiving 

waters after effluent is discharged. Stress caused by reduced dissolved oxygen levels makes 

organisms less competitive and less able to sustain their species in the aquatic environment. 

Although BOD is not a specific compound, it is defined as a conventional pollutant under the 

federal Clean Water Act.

Bypass: The intentional diversion of waste streams from any portion of a treatment facility.

Chlorine: Chlorine is used to disinfect wastewaters of pathogens harmful to human health. It is 

also extremely toxic to aquatic life.
Page 47

Chronic Toxicity: The effect of a compound on an organism over a relatively long time, often 

1/10 of an organism's lifespan or more. Chronic toxicity can measure survival, reproduction 

or growth rates, or other parameters to measure the toxic effects of a compound or 

combination of compounds.

Clean Water Act (CWA): The Federal Water Pollution Control Act enacted by Public Law 92-

500, as amended by Public Laws 95-217, 95-576, 96-483, 97-117; USC 1251 et seq.

Compliance Inspection: Without Sampling: A site visit for the purpose of determining the 

compliance of a facility with the terms and conditions of its permit or with applicable statutes 

and regulations.

Compliance Inspection: With Sampling: A site visit for the purpose of determining the 

compliance of a facility with the terms and conditions of its permit or with applicable statutes 

and regulations. In addition it includes as a minimum, sampling and analysis for all 

parameters with limits in the permit to ascertain compliance with those limits; and, for 

municipal facilities, sampling of influent to ascertain compliance with the 85 percent removal 

requirement. Ecology may conduct additional sampling.

Composite Sample: A mixture of grab samples collected at the same sampling point at different 

times, formed either by continuous sampling or by mixing discrete samples. May be "timecomposite"(collected at constant time intervals) or "flow-proportional" (collected either as a 

constant sample volume at time intervals proportional to stream flow, or collected by 

increasing the volume of each aliquot as the flow increased while maintaining a constant time 

interval between the aliquots.

Construction Activity: Clearing, grading, excavation and any other activity which disturbs the 

surface of the land. Such activities may include road building, construction of residential 

houses, office buildings, or industrial buildings, and demolition activity.

Continuous Monitoring: Uninterrupted, unless otherwise noted in the permit.

Critical Condition: The time during which the combination of receiving water and waste 

discharge conditions have the highest potential for causing toxicity in the receiving water 

environment. This situation usually occurs when the flow within a water body is low, thus, 

its ability to dilute effluent is reduced.

Detection Limit: See Method Detection Level.

Dilution Factor (DF): A measure of the amount of mixing of effluent and receiving water that 

occurs at the boundary of the mixing zone. Expressed as the inverse of the percent effluent

fraction e.g., a dilution factor of 10 means the effluent comprises 10% by volume and the 

receiving water 90%.

Engineering Report: A document which thoroughly examines the engineering and 

administrative aspects of a particular domestic or industrial wastewater facility. The report 

must contain the appropriate information required in WAC 173-240-060 or 173-240-130.
Page 48

Fecal Coliform Bacteria: Fecal coliform bacteria are used as indicators of pathogenic bacteria 

in the effluent that are harmful to humans. Pathogenic bacteria in wastewater discharges are 

controlled by disinfecting the wastewater. The presence of high numbers of fecal coliform 

bacteria in a water body can indicate the recent release of untreated wastewater and/or the 

presence of animal feces.

Grab Sample: A single sample or measurement taken at a specific time or over as short a period 

of time as is feasible.

Industrial Wastewater: Water or liquid-carried waste from industrial or commercial processes, 

as distinct from domestic wastewater. These wastes may result from any process or activity 

of industry, manufacture, trade or business, from the development of any natural resource, or 

from animal operations such as feed lots, poultry houses, or dairies. The term includes 

contaminated storm water and, also, leachate from solid waste facilities.

Major Facility: A facility discharging to surface water with an EPA rating score of > 80 points 

based on such factors as flow volume, toxic pollutant potential, and public health impact.

Maximum Daily Discharge Limit: The highest allowable daily discharge of a pollutant 

measured during a calendar day or any 24-hour period that reasonably represents the calendar 

day for purposes of sampling. The daily discharge is calculated as the average measurement 

of the pollutant over the day.

Maximum Day Design Flow (MDDF): The largest volume of flow anticipated to occur during a 

one-day period, expressed as a daily average.

Maximum Month Design Flow (MMDF): The largest volume of flow anticipated to occur 

during a continuous 30-day period, expressed as a daily average.

Maximum Week Design Flow (MWDF): The largest volume of flow anticipated to occur during a 

continuous 7-day period, expressed as a daily average.

Method Detection Level (MDL): The minimum concentration of a substance that can be 

measured and reported with 99% confidence that the pollutant concentration is above zero 

and is determined from analysis of a sample in a given matrix containing the pollutant.

Minor Facility: A facility discharging to surface water with an EPA rating score of < 80 points 

based on such factors as flow volume, toxic pollutant potential, and public health impact.

Mixing Zone: An area that surrounds an effluent discharge within which water quality criteria 

may be exceeded. The area of the authorized mixing zone is specified in a facility's permit 

and follows procedures outlined in state regulations (chapter 173-201A WAC).

National Pollutant Discharge Elimination System (NPDES): The NPDES (Section 402 of the 

Clean Water Act) is the Federal wastewater permitting system for discharges to navigable 

waters of the United States. Many states, including the State of Washington, have been 

delegated the authority to issue these permits. NPDES permits issued by Washington State 

permit writers are joint NPDES/State permits issued under both State and Federal laws.

pH: The pH of a liquid measures its acidity or alkalinity. It is the negative logarithm of the 

hydrogen ion concentration. A pH of 7 is defined as neutral, and large variations above or 

below this value are considered harmful to most aquatic life.
Page 49

Peak Hour Design Flow (PHDF): The largest volume of flow anticipated to occur during a onehour period, expressed as a daily or hourly average.

Peak Instantaneous Design Flow (PIDF): The maximum anticipated instantaneous flow.

Quantitation Level (QL): The smallest detectable concentration of analyte greater than the 

Detection Limit (DL) where the accuracy (precision &bias) achieves the objectives of the 

intended purpose. This may also be called Minimum Level or Reporting Level.

Reasonable Potential: A reasonable potential to cause a water quality violation, or loss of 

sensitive and/or important habitat.

Responsible Corporate Officer: A president, secretary, treasurer, or vice-president of the 

corporation in charge of a principal business function, or any other person who performs 

similar policy- or decision-making functions for the corporation, or the manager of one or 

more manufacturing, production, or operating facilities employing more than 250 persons or 

have gross annual sales or expenditures exceeding $25 million (in second quarter 1980 

dollars), if authority to sign documents has been assigned or delegated to the manager in 

accordance with corporate procedures (40 CFR 122.22).

Technology-Based Effluent Limit: A permit limit that is based on the ability of a treatment 

method to reduce the pollutant.

Total Suspended Solids (TSS): The particulate material in an effluent. Large quantities of TSS 

discharged to receiving waters may result in solids accumulation. Apart from any toxic 

effects attributable to substances leached out by water, suspended solids may kill fish, 

shellfish, and other aquatic organisms by causing abrasive injuries and by clogging the gills 

and respiratory passages of various aquatic fauna. Indirectly, suspended solids can screen 

out light and can promote and maintain the development of noxious conditions through 

oxygen depletion. 

Solid Waste: All putrescible and non-putrescible solid and semisolid wastes including, but not 

limited to, garbage, rubbish, ashes, industrial wastes, swill, sewage sludge, demolition and 

construction wastes, abandoned vehicles or parts thereof, contaminated soils and 

contaminated dredged material, and recyclable materials.

State Waters: Lakes, rivers, ponds, streams, inland waters, underground waters, salt waters, and 

all other surface waters and watercourses within the jurisdiction of the state of Washington.

Stormwater: That portion of precipitation that does not naturally percolate into the ground or 

evaporate, but flows via overland flow, interflow, pipes, and other features of a storm water 

drainage system into a defined surface water body, or a constructed infiltration facility.

Upset: An exceptional incident in which there is unintentional and temporary noncompliance 

with technology-based permit effluent limits because of factors beyond the reasonable 

control of the facility. An upset does not include noncompliance to the extent caused by 

operational error, improperly designed treatment facilities, lack of preventative maintenance, 

or careless or improper operation.

Water Quality-Based Effluent Limit: A limit on the concentration of an effluent parameter that 

is intended to prevent the concentration of that parameter from exceeding its water quality 

criterion after it is discharged into receiving waters.
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APPENDIX C - WASTEWATER TREATMENT FLOW DIAGRAM

APPENDIX D - MONTHLY DISCHARGE MONITORING REPORTS 

APPENDIX E - TECHNICAL LIMIT CALCULATION

APPENDIX F - DRY WEATHER FLOW CALCULATION

APPENDIX G - STORMWATER ALLOCATION EVENTS

APPENDIX H - REASONABLE POTENTIAL TO EXCEED ANALYSIS

Several of the Excel® spreadsheet tools used to evaluate a discharger’s ability to meet 

Washington State water quality standards can be found on Ecology’s homepage at 

http://www.ecy.wa.gov/programs/eap/pwspread/pwspread.html.

APPENDIX I - MIXING ZONE ANALYSIS DATA

APPENDIX J - TEMPERATURE ANALYSIS

APPENDIX K - HERRING AND WET TESTING RESULTS 

APPENDIX L - PERFORMANCE-BASED REDUCTION OF MONITORING 

FREQUENCY

APPENDIX M - RESPONSE TO COMMENTS