Permit No. COG-840000

CDPS GENERAL PERMIT

FOR 

DISCHARGES ASSOCIATED WITH PRODUCED-WATER TREATMENT FACILITIES

COLORADO DISCHARGE PERMIT SYSTEM

In compliance with the provisions of the Colorado Water Quality Control Act, (25-8-101 et seq., CRS, 1973 as 

amended), facilities engaged in the discharge of produced-water generated from oil and gas producing 

formations are authorized to discharge from authorized locations throughout the State of Colorado to specified 

waters of the state. Such discharges shall be in accordance with conditions of this general permit.

The applicant may demand an adjudicatory hearing within thirty (30) days of the date of issuance of the final 

permit determination, per the Colorado Discharge Permit System Regulations, 61.7(1). Should the applicant 

choose to contest any of the effluent limitations, monitoring requirements or other conditions contained herein, 

the applicant must comply with Section 24-4-104 CRS and the Colorado Discharge Permit System Regulations. 

Failure to contest any such effluent limitation, monitoring requirement, or other condition, constitutes consent to 

the condition by the Applicant.

This permit specifically authorizes the facility listed on page 1 of this permit to discharge treated producedwaters, as of the date stated below, in accordance with the permit requirments and conditions set forth in Parts I 

and II hereof. All discharges authorized herein shall be consistent with the terms and conditions of this permit.

This permit and the authorization to discharge shall expire at midnight, August 31, 2014.

Modified , Reissued and Signed this 30th day of January 2012.

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT

Janet Kieler, Permits Section Manager

Water Quality Control Division

Permit Action Summary:

Modification 1: Issued and Signed: January 30, 2012 Effective March 1, 2012: Part I.A.1; 

 Part I.C.2 and 3; Part I.D; Part II.A.4 and 5; and Table 1.B.1

Originally Issued And Signed : July 31, 2009, Effective Date Of Permit : September 1, 2009
 PART I

 Page 2 of 41

Permit No.: COG-840000

TABLE OF CONTENTS

PART I ............................................................................................................................................................................................................................3

A. COVERAGE UNDER THIS PERMIT....................................................................................................................................3

B. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS ...........................................................................5

C. TERMS AND CONDITIONS...................................................................................................................................................8

1. Facilities Operation and Maintenance ..................................................................................................................................8

2. Acute WET Testing Requirements.......................................................................................................................................8

3. Chronic WET Testing Requirements..................................................................................................................................11

4. Compliance Schedules........................................................................................................................................................15

D. DEFINITIONS OF TERMS ...................................................................................................................................................16

E. GENERAL MONITORING, SAMPLING AND REPORTING REQUIREMENTS........................................................23

1. Routine Reporting of Data..................................................................................................................................................23

2. Representative Sampling ....................................................................................................................................................23

3. Analytical and Sampling Methods for Monitoring and Reporting......................................................................................24

4. Records...............................................................................................................................................................................26

5. Flow Measuring Device......................................................................................................................................................27

6. Signatory and Certification Requirements..........................................................................................................................27

PART II.........................................................................................................................................................................................................................29

A. NOTIFICATION REQUIREMENTS....................................................................................................................................29

1. Notification to Parties.........................................................................................................................................................29

2. Change in Discharge...........................................................................................................................................................29

3. Special Notifications - Definitions ..........................................................................................................................................30

4. Noncompliance Notification....................................................................................................................................................30

5. Other Notification Requirements...........................................................................................................................................31

6. Bypass Notification..................................................................................................................................................................32

7. Upsets........................................................................................................................................................................................32

8. Discharge Point........................................................................................................................................................................33

9. Proper Operation and Maintenance ......................................................................................................................................33

10. Minimization of Adverse Impact............................................................................................................................................33

11. Removed Substances................................................................................................................................................................33

12. Submission of Incorrect or Incomplete Information ............................................................................................................33

13. Bypass.......................................................................................................................................................................................33

14. Reduction, Loss, or Failure of Treatment Facility................................................................................................................34

B. RESPONSIBILITIES..............................................................................................................................................................34

1. Inspections and Right to Entry............................................................................................................................................34

2. Duty to Provide Information...............................................................................................................................................35

3. Transfer of Ownership or Control ......................................................................................................................................35

4. Availability of Reports .......................................................................................................................................................35

5. Modification, Suspension, Revocation, or Termination of Permits By the Division ..........................................................36

6. Oil and Hazardous Substance Liability...............................................................................................................................39

7. State Laws ..........................................................................................................................................................................39

8. Permit Violations................................................................................................................................................................39

9. Property Rights...................................................................................................................................................................39

10. Severability.........................................................................................................................................................................40

11. Renewal Application ..........................................................................................................................................................40

12. Confidentiality....................................................................................................................................................................40

13. Fees.....................................................................................................................................................................................40

14. Duration of Permit..............................................................................................................................................................40

15. Section 307 Toxics.............................................................................................................................................................40

16. Effect of Permit Issuance....................................................................................................................................................41
 PART I

 Page 3 of 41

Permit No.: COG-840000

PART I

A. COVERAGE UNDER THIS PERMIT

1. This general permit authorizes facilities engaged in the treatment and/or disposal of produced-water*,

generated from oil and gas producing formations, to discharge from authorized locations throughout the 

State of Colorado to surface waters of the state. Discharges to groundwater are not authorized under this 

general permit and would be subject to the jurisdiction of the Colorado Oil and Gas Conservation 

Commission (COGCC). Underground injection wells may be under the authority of the COGCC or of 

EPA, depending on the type and/or depth of the well. Recycling and/or beneficial uses may be under the 

authority of the COGCC or the Solid Waste and Materials Management Program (within the Hazardous 

Materials and Waste Management Division), depending on the nature of the beneficial use. Due to the 

nature of general permits, determinations of the assimilative capacity of the receiving stream(s) are not 

available. All limitations set in this permit are based upon the most stringent of: 1) the site-specific water 

quality standards; 2) the Regulations for Effluent Limitations (Reg 62) and/or; the Federal Effluent 

Limitation Guidelines. Multiple discharge points from one fixed, or from a mobile facility may be 

authorized through a certification under this permit.

Discharges may be covered under this permit at the Division's discretion, providing that such wastewater 

would not require effluent limitations and/or monitoring requirements other than those contained in this 

permit. Such determinations will be made on a case-by-case basis upon review of the permit application 

and any additional relevant information. If a discharge source requires additional limitations and/or 

monitoring requirements, an individual permit may be required. Additionally, due to the nature of public 

interest in oil and gas permits, the Division may determine that a specific permit would have a high level 

of public interest. If such determination is made, the Division will require an individual permit in order 

to provide the public an opportunity to comment. However, the Division will also take into account that 

coverage under a general permit provides the most stringent limitations (since limitations are set at the 

stream standards), applicable in a discharge permit.

* Produced water includes all waters and particulate matter associated with oil and gas producing 

formations. Consistent with the scope of the oil and gas extraction point source category established by 

EPA in the development of Federal Effluent Limitation Guidelines (ELGs), produced water discharges 

associated with production of crude petroleum and natural gas, drilling oil and gas wells, and oil and 

gas field exploration services are included within the scope of the permit. In addition to formation 

water, produced water may be commingled with injection water, any chemicals added downhole, 

chemicals added during the oil/water separation processes, or chemicals added during the treatment 

process

2. In order to apply for certification under this general permit, the owner, operator, and/or authorized agent 

of the subject facility shall submit by certified mail or hand delivery, the completed application for an 

individual permit. 

 If the discharge is to a storm sewer system, ditch, or other manmade conveyance, approval from 

 the owner of the system must be obtained before discharge. 

 At least 60 days before the anticipated date of discharge, the application in its entirety, shall be 

submitted to: 
 PART I

 Page 4 of 41

Permit No.: COG-840000

Colorado Department of Public Health and Environment 

Water Quality Control Division 

Permits Section, WQCD-PCP-B2

4300 Cherry Creek Drive South 

Denver, CO 80246 

Following review of the application, the Division may request additional data or deny the authorization 

to discharge under this general permit. If the Division determines that a new facility does not fall under 

the authority of the general permit, then the information received will be processed for an individual 

permit, and the applicant shall be notified of such a determination. If during the renewal process, the 

Division determines that a facility no longer qualifies for the general permit, then the certification may 

be terminated or the facility may be allowed to discharge under the general permit ,with additional 

conditions in the amended certification, until an individual permit is issued. 

3. The final limitations to be applied under this permit shall take into consideration the application of the 

appropriate discharge categories, applicable water quality standards, control regulations, total maximum 

daily loads, and other regulatory requirements. Effluent limitations will be applied in certifications in 

accordance with the effluent limitations provided in Part I.B below

4. Authorization to discharge under this general permit shall expire on midnight August 31, 2014.The 

Division must evaluate this general permit once every five years and must recertify all applicants' 

authority to discharge under the general permit at that time. Therefore, a permittee desiring continued 

coverage under the general permit must reapply by February 28, 2013. The submittal of a complete 

application will allow for an administrative extension of the certification, under such time as the general 

permit is renewed and a new certification issued to the facility. 

5. Chemicals that may be present in the discharge, whether added during exploration/production, or after 

the formation water has reached the surface of the well, will be provided in the permit application with 

each chemical’s MSDS sheet. All chemicals must be used and stored in accordance with the 

manufacturers recommendations and in accordance with any applicable state or federal regulations. 

6. There shall be no discharge of solid animal or food waste, vegetative wastes (grass, leaves, manure, 

garbage, etc), or any floating solids or visible foam, in other than trace amounts. 

7. All discharges must comply with the lawful requirements of federal agencies, municipalities, counties, 

drainage districts and other local agencies regarding any discharges to storm drains systems, 

conveyances, or other water courses under their jurisdiction. In addition, prior to the discharge the 

permittee must notify the owner of the system of the date, approximate time, location, and duration of 

the discharge(s). 

8. Bulk storage structures for petroleum products and other chemicals shall have secondary containment or 

equivalent adequate protection so as to contain all spills and prevent any spilled material from entering 

discharged waters or waters of the State. 
 PART I

 Page 5 of 41

Permit No.: COG-840000

B. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

Under this general permit, the limitations and monitoring requirements (Table B.I.1) are determined on the 

basis of -

state water-quality standards that apply to all waters (i.e. statewide),

state water-quality standards that apply to specific stream segments (i.e., receiving water),

state effluent limitations (i.e., treatment specific),

state watershed limitations (i.e., phosphorus and salinity control),

state policies (i.e., guidance on how specific standards are implemented in permits),

interstate watershed limitations (i.e, total dissolved solids), and

federal effluent limitation guidelines (i.e., industry specific).

In the table, the parameters are listed under general categories and the basis for the limitation is identified in 

the last column.

 Table I.B.1 Discharge Limitations and Monitoring Conditions

Effluent Parameter

Discharge Limitations Monitoring Conditions

Basis for 

Limitation

30-Day 

Average

7-Day 

Average

Daily 

Maximum

Monitoring 

Frequency 2 Sample Type 3

Flow, mgd Limit 1 NA Report Continuous Recorder Regulation 61

Temperature, ° C

 

NA

NA

NA

NA

TVS TVS

Continuous Recorder

Water Quality 

Standards

Regulations 31-

38

Total Suspended

Solids, mg/ 30 45 NA

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical) Regulation 62

Total Dissolved Solids, 

mg/l

1 ton/day 

or 350 

tons/year

NA NA Quarterly

Grab (lagoon)

Composite (mechanical)

Regulations 39 

and 61

Total Dissolved Solids, 

mg/l 3500 NA NA Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Narrative 

Standard

pH, s.u. NA NA 6.5-9.0

Weekly (major)

2 days/month 

(minor)

Grab

Water Quality 

Standards

Regulations 31-

38

Radium 226+228, pCi/l NA NA 5

Case by Case Basis Grab

Water Quality 

Standards

Regulation 31

Organics or other 

Radionuclides as 

deemed necessary

Various NA Various Case by Case Basis Grab

Water Quality 

Standards 

Regulation 31

 

 Sulfide

Chloride,mg/l 250 NA NA

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31
 PART I

 Page 6 of 41

Permit No.: COG-840000

Sulfate, mg/l 250 NA NA

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31

Sulfide, mg/l 0.002 NA NA

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31

Cyanide, ug/l NA NA 5

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31

Nitrate, mg/l NA NA Various

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31

Nitrite, mg/l NA NA Various

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31

Boron, mg/l 0.75 NA NA

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards 

Regulations 31

Metals, ug/l TVS NA TVS

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Water Quality 

Standards

Regulation 31-

38

Organic Chemicals, 

ug/l

Oil and Grease mg/l

 Conventional oil 

and 

 and gas operations 

subject to Federal ELG 

 Other oil and gas 

 Operations not 

subject to ELG

NA

NA

NA

NA

35

10

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

40 CFR 435 

(ELG)

Regulation 62

 

WET, chronic NA NA NOEC or

IC25 >100% Quarterly 4

3 Grabs or Composites / test

Narrative 

Standards 

Policy 

WET, acute NA NA LC50 

>100% Quarterly 4

3 Grabs / test Narrative 

Standard

Water Quality Policy 

#24 Parameters

 Electrical 

 Conductivity, dS/m

 

 

 

Various NA Various

Weekly (major)

2 days/month 

(minor)

Grab (lagoon)

Composite (mechanical)

Narrative 

Standards

Policy

(WQP#24)

SAR limit, calculated 5 Report Calculated

Adjusted SAR 6 Report Calculated

SAR, pass/fail 7Pass/Fail Calculated

Sodium, mg/l Report Report Grab (lagoon)

Calcium, mg/l Report Report Composite (mechanical)

Magnesium, mg/l Report Report Grab (lagoon)

Bicarbonate, mg/l Report Report Composite (mechanical)

Blending Ratio 

(Influent/Effluent) 8 NA NA Report Weekly Calculated Treatment Characterization

 See the definitions in Part I.D for additional information on any of the following or above items.
 PART I

 Page 7 of 41

Permit No.: COG-840000

Notes: 1) Flow limit to be based on design capacity of the treatment process as provided in the application for certification, or a 

reasonable expectation of actual discharge (not to be exceeded).

 2) The Division reserves the right to increase or decrease monitoring frequencies as determined to be necessary,

3) Sample types may change based on the specific parameter or configuration of the facility.

4) WET testing shall normally be on a quarterly basis, although the Division retains authority to vary the frequency as stated in 

the WET Policy

5) This SAR limit is to be calculated using the actual measured EC value (30-day average) of the effluent and substituting this 

value in to the following equation to solve for SAR. The equation for determining the SAR limit is: SAR = (7.1 * EC) – 2.48. 

This limitation is capped at the more stringent value of 9.0, or that determined in the specific certification based on crop 

type.

6) The SAR value of the effluent is to be reported as the adjusted SAR. See the definitions section in Part I.C.17 for information 

on calculating the adjusted SAR value.

7) The permittee shall compare the SAR value of the effluent (adjusted SAR) to this calculated SAR limitation and report as 

Pass/Fail whether the effluent SAR meets this value. If the SAR effluent value (adjusted SAR) is less than or equal to the 

calculated limit, then the permittee will report “Pass” and if it is greater than the calculated limit the permittee will report “Fail.” 

8) Blending Ratio- The may be instances where the treated produced water may require chemical augmentation to compensate for 

low ionic strength and contribute to passage of the WET test. This reporting requirement is included to provide the Division 

with this information.

The parameters in Table I.B.1 are the potential pollutants of concern (POC) that will be used by the 

permit writer in developing the limitations in certifications under this general permit. The POCs for a 

certification will be selected based on a review of examples of chemical profiles of untreated produced 

water, experience in development of individual permits for discharges of produced waters from oil and 

gas operations, and general knowledge of produced waters. Other POCs can be included, by the permit 

writer, with limitations and monitoring requirements based on information in the application, including 

produced water characterization and proposed treatment technology, and the further need for water 

quality protection at a specific discharge location (i.e, parameters identified in 303d Listing, TMDLbased waste load allocation). The issued certification will document the permit writer’s evaluations and 

determinations that resulted in the selection of additional POCs with monitoring and limitation 

requirements.

“TVS” or “Various” is entered in Table I.B.1 for POCs where the determination of the limitation and 

monitoring is dependent on evaluation of site-specific information (i.e., water-quality standards that 

apply to specific stream segments, assigned classification, designated beneficial uses, limitations for 

discharges to specific watersheds, hardness of receiving water, ratio of discharge flow to receiving water 

flow, concentrations of specific salts in the receiving water, downstream diversion for water supply or 

crop irrigation, and quality of the produced water). Regulation 31 describes the beneficial uses that can 

be assigned to a receiving water segment and the associated water-quality standards. For a discharge to a 

specific stream segment, the basin regulations (i.e., Regulations 32-38) provide the water quality 

standards that apply to each stream segment, as well as information on classification for antidegradation 

review and on temporary modifications. Other Regulations or Policies may also be used to develop sitespecific limitations. 

The results of the site-specific determinations, involving water-quality standards, are subject, per 

regulations, to reasonable potential analysis and antidegradation review before monitoring and 

limitations requirements are entered in the certification. Qualitative reasonable potential determinations 

may be made for some parameters based on information in the application. Further qualitative 

reasonable potential analysis will be utilized to determine which additional parameters will be placed in 

the certification and the need for limits (with monitoring) or for monitoring only. The permit writer will 

conduct this analysis based on a comparison of the chemical profile of the untreated produced water (as 

provide in the application for a certification) with the limitations listed in Table I.B.1. Monitoring only 

requirements can be imposed to generate additional information for a future reasonable potential 

analysis, which could find that continued monitoring is not required and the certification would be 
 PART I

 Page 8 of 41

Permit No.: COG-840000

amended to remove this requirement. For waters, other than “Use Protected” waters, an antidegradation 

review is required. In these instances, a second qualitative reasonable potential analysis will be 

performed comparing the produced-water parameters to a value equal to 15% of the limit provided as a 

result of applying information in Table I.B.1.

C. TERMS AND CONDITIONS

1. Facilities Operation and Maintenance

The permittee shall at all times properly operate and maintain all facilities and systems of treatment and 

control (and related appurtenances) which are installed or used by the permittee as necessary to achieve 

compliance with the conditions of this permit. Proper operation and maintenance also includes adequate 

laboratory controls and appropriate quality assurance procedures. This provision requires the operation 

of back-up or auxiliary facilities or similar systems when installed by the permittee only when necessary 

to achieve compliance with the conditions of the permit. Any sludge produced at the wastewater 

treatment facility shall be disposed of in accordance with State and Federal guidelines and regulations. 

2. Acute WET Testing Requirements 

a. General Acute WET Testing and Reporting Requirements

The permittee shall conduct an acute 48-hour WET test using Ceriodaphnia dubia (or Daphnia 

magna or Daphnia pulex if stated in the certification), and an acute 96-hour WET test using 

Pimephales promelas (or rainbow trout or brook trout if stated in the certification). Acute tests 

shall be conducted as a static replacement test using a single effluent grab sample. The permittee 

shall conduct each acute WET test in accordance with the 40 CFR Part 136 methods described in 

Methods for Measuring the Acute Toxicity of Effluents and Receiving Water to Freshwater and 

Marine Organisms, Fifth Edition, October 2002 (EPA-821-R-02-012) or its most current edition. 

The following specifications may be used if stated in the certification: 

Use of the 0.01 alpha level – The permittee has requested use of the 0.01 alpha level, and 

therefore this alpha level shall be used for every WET test under this permit. The permittee is 

responsbile for determining whether an increase in replicates within each individual test is 

needed to assure that the test meets the minimum sensitivity requirements. Chapter 2 of the 

Method Guidance and Recommendations for Whole Effluent Toxicity (WET) Testing, EPA 821-

B-00-004, USEPA, July 2000, must be used to calculate and determine if the minimum 

significant difference (MSD) requirement has been met. If this requirement is not met, the test is 

considered invalid and retesting must be performed during the monitoring period. The permittee 

will be required to submit documentation showing that the appropriate number of replicates was 

used and that the proper MSD criterion has been met, with the WET information summary that is 

submitted to the Division with the WET test results. 

Use of a CO2 atmosphere to control pH drift – The use of a CO2 stmosphere will be allowed to 

control ammonia toxicity due to pH drift. The proper methodology as outlined in the Chronic 

Method must be followed and documented during the test. The permittee will be required to 

submit documentation showing that the proper methodology was used in the testing with the 

WET information summary that is submitted to the Division with the WET test results. 
 PART I

 Page 9 of 41

Permit No.: COG-840000

The following minimum dilution series should be used: 0% effluent (control), 20%, 40%, 60%, 80%, 

and 100% effluent If the permittee uses more dilutions than prescribed, and accelerated testing is to 

be performed, the same dilution series shall be used in the accelerated testing as was used in the 

failed test.

Tests shall be done at the frequency listed in Part I.A.1. Test results shall be reported along with the 

Discharge Monitoring Report (DMR) submitted for the end of the reporting period when the sample 

was taken. (i.e., WET testing results for the calendar quarter ending March 31 shall be reported with 

the DMR due April 28, etc.) The permittee shall submit all laboratory statistical summary sheets, 

summaries of the determination of a valid, invalid or inconclusive test, and copies of the chain of 

custody forms, along with the DMR for the reporting period. 

If a test is considered invalid, the permittee is required to perform additional testing during the 

monitoring period to obtain a valid test result. Failure to obtain a valid test result during the 

monitoring period shall result in a violation of the permit for failure to monitor.

b. Violations of the Permit Limit and Division Notification

An acute WET test is failed whenever the LC50, which represents an estimate of the effluent 

concentration which is lethal to 50% of the test organisms in the time period prescribed by the test, is 

found to be less than or equal to 100% effluent. The permittee must provide written notification of 

the failure of a WET test to the Division, along with a statement as to whether accelerated testing or 

a Toxicity Identification Evaluation (TIE) is being performed, unless otherwise exempted, in writing, 

by the Division. Notification must be received by the Division within 14 calendar days of the 

permittee receiving notice of the WET testing results. 

c. Automatic Compliance Response

The permittee is responsible for implementing the automatic compliance response provisions of this 

permit when one of the following occurs:

there is a violation of the permit limit (the LC50 endpoint is less than the applicable IWC)

the permittee is otherwise informed by the Division that a compliance response is necessary

When one of the above listed events occurs, the following automatic compliance response shall 

apply. The permittee shall either: 

conduct accelerated testing using the single species found to be more sensitive

conduct a Toxicity Identification Evaluation / Toxicity Reduction Evaluation (TIE/TRE) 

investigation as described in Part I.A.3.b.

i. Accelerated Testing

If accelerated testing is being performed, testing will be at least once every two weeks for up to 

five tests, at the appropriate IWC, but only one test should be run at a time. Accelerated testing 
 PART I

 Page 10 of 41

Permit No.: COG-840000

shall continue until; 1) two consecutive tests fail or three of five tests fail, in which case a pattern 

of toxicity has been demonstrated or 2) two consecutive tests pass or three of five tests pass, in 

which case no pattern of toxicity has been found. Note that the same dilution series should be used 

in the accelerated testing as was used in the initial test(s) that result in the accelerated testing 

requirement. 

If no pattern of toxicity is found the toxicity episode is considered to be ended and routine testing 

is to resume. If a pattern of toxicity is found, a TIE/TRE investigation is to be performed. If a 

pattern of toxicity is not demonstrated but a significant level of erratic toxicity is found, the 

Division may require an increased frequency of routine monitoring or some other modified 

approach. The permittee shall provide written notification of the results within 14 calendar days of 

completion of the Pattern of Toxicity/No Toxicity demonstration. 

ii. Toxicity Identification Evaluation / Toxicity Reduction Evaluation (TIE/TRE)

If a TIE/TRE is being performed, the results of the investigation are to be received by the Division 

within 180 calendar days of the demonstration of acute WET in the routine test, as defined above, 

or if accelerated testing was performed, the date the pattern of toxicity is demonstrated. A status 

report is to be provided to the Division at the 60 and 120 calendar day points of the TIE/TRE 

investigation. The Division may extend the time frame for investigation where reasonable 

justification exists. A request for an extension must be made in writing and received prior to the 

180 calendar day deadline. Such request must include a justification and supporting data for such 

an extension. 

Under a TIE, the permittee may use the time for investigation to conduct a preliminary TIE (PTIE) 

or move directly into the TIE. A PTIE consists of a brief search for possible sources of WET, 

where a specific parameter(s) is reasonably suspected to have caused such toxicity, and could be 

identified more simply and cost effectively than a formal TIE. If the PTIE allows resolution of the 

WET incident, the TIE need not necessarily be conducted in its entirety. If, however, WET is not 

identified or resolved during the PTIE, the TIE must be conducted within the allowed 180 calendar 

day time frame. 

The Division recommends that the EPA guidance documents regarding TIEs be followed. If 

another method is to be used, this procedure should be submitted to the Division prior to initiating 

the TIE. 

If the pollutant(s) causing toxicity is/are identified, and is/are controlled by a permit effluent 

limitation(s), this permit may be modified upon request to adjust permit requirements regarding the 

automatic compliance response. 

If the pollutant(s) causing toxicity is/are identified, and is/are not controlled by a permit effluent 

limitation(s), the Division may develop limitations the parameter(s), and the permit may be 

reopened to include these limitations. 

If the pollutant causing toxicity is not able to be identified, or is unable to be specifically identified, 

or is not able to be controlled by an effluent limit, the permittee will be required to perform either 

item 1 or item 2 below. 
 PART I

 Page 11 of 41

Permit No.: COG-840000

l) Conduct an investigation which demonstrates actual instream aquatic life conditions 

upstream and downstream of the discharge, or identify, for Division approval, and conduct an 

alternative investigation which demonstrates the actual instream impact. This should include 

WET testing and chemical analyses of the ambient water. Depending on the results of the 

study, the permittee may also be required to identify the control program necessary to eliminate 

the toxicity and its cost. Data collected may be presented to the WQCC for consideration at the 

next appropriate triennial review of the stream standards;

2) Move to a TRE by identifying the necessary control program or activity and proceed with 

elimination of the toxicity so as to meet the WET effluent limit. 

If toxicity spontaneously disappears in the midst of a TIE, the permittee shall notify the Division 

within 10 calendar days of such disappearance. The Division may require the permittee to conduct 

accelerated testing to demonstrate that no pattern of toxicity exists, or may amend the permit to 

require an increased frequency of WET testing for some period of time. If no pattern of toxicity is 

demonstrated through the accelerated testing or the increased monitoring frequency, the toxicity 

incident response will be closed and normal WET testing shall resume.

The control program developed during a TRE consists of the measures determined to be the most 

feasible to eliminate WET. This may happen through the identification of the toxicant(s) and then 

a control program aimed specifically at that toxicant(s) or through the identification of more 

general toxicant treatability processes. A control program is to be developed and submitted to the 

Division within 180 calendar days of beginning a TRE. Status reports on the TRE are to be 

provided to the Division at the 60 and 120 calendar day points of the TRE investigation.

If toxicity spontaneously disappears in the midst of a TRE, the permittee shall notify the Division 

within 10 calendar days of such disappearance. The Division may require the permittee to conduct 

accelerated testing to demonstrate that no pattern of toxicity exists, or may amend the permit to 

require an increased frequency for some period of time. If no pattern of toxicity is demonstrated 

through the accelerated testing or the increased monitoring frequency, the toxicity incident 

response will be closed and normal WET testing shall resume.

d. Toxicity Reopener

This permit may be reopened and modified to include additional or modified numerical permit 

limitations, new or modified compliance response requirements, changes in the WET testing 

protocol, the addition of both acute and chronic WET requirements, or any other conditions related 

to the control of toxicants.

3. Chronic WET Testing Requirements

a. General Chronic WET Testing and Reporting Requirements

The permittee shall conduct the chronic WET test using Ceriodaphnia dubia and Pimephales 

promelas, as a static renewal 7-day test using three separate composite or grab samples, as stated in 

the certification. The permittee shall conduct each chronic WET test in accordance with the 40 CFR 
 PART I

 Page 12 of 41

Permit No.: COG-840000

Part 136 methods described in Short-term Methods for Estimating the Chronic Toxicity of Effluents 

and Receiving Water to Freshwater Organisms, Fourth Edition, October 2002 (EPA-821-R-02-013) 

or the most current edition. 

The following specifications may be used if stated in the certification: 

Use of the 0.01 alpha level – The permittee has requested use of the 0.01 alpha level, and 

therefore this alpha level shall be used for every WET test under this permit. The permittee is 

responsbile for determining whether an increase in replicates within each individual test is 

needed to assure that the test meets the minimum sensitivity requirements. Chapter 2 of the 

Method Guidance and Recommendations for Whole Effluent Toxicity (WET) Testing, EPA 821-

B-00-004, USEPA, July 2000, must be used to calculate and determine if the minimum 

significant difference (MSD) requirement has been met. If this requirement is not met, the test is 

considered invalid and retesting must be performed during the monitoring period. The permittee 

will be required to submit documentation showing that the appropriate number of replicates was 

used and that the proper MSD criterion has been met, with the WET information summary that is 

submitted to the Division with the WET test results. 

Use of a CO2 atmosphere to control pH drift – The use of a CO2 stmosphere will be allowed to 

control ammonia toxicity due to pH drift. The proper methodology as outlined in the Chronic 

Method must be followed and documented during the test. The permittee will be required to 

submit documentation showing that the proper methodology was used in the testing with the 

WET information summary that is submitted to the Division with the WET test results. 

Ceriodaphnia reproduction percentage - For the chronic Ceriodaphnia dubia test, the termination 

requirement shall be where 80% or more of the surviving control females having produced their 

third brood. If this requirement is not met, the test is considered invalid and retesting must be 

performed during the monitoring period. The permittee will be required to submit 

documentation showing that the appropriate number of the surviving control females have had 

their third brood with the WET information summary that is submitted to the Division with the 

WET test results. 

The following minimum dilution series should be used: 0% effluent (control), 20%, 40%, 60%, 80%, 

and 100% effluent. If the permittee uses more dilutions than prescribed, and accelerated testing is to 

be performed, the same dilution series shall be used in the accelerated testing (if applicable) as was 

initially used in the failed test.

Tests shall be done at the frequency listed in Part I.A.1. Test results shall be reported along with the 

Discharge Monitoring Report (DMR) submitted for the end of the reporting period when the sample

was taken. (i.e., WET testing results for the calendar quarter ending March 31 shall be reported with 

the DMR due April 28, etc.) The permittee shall submit all laboratory statistical summary sheets, 

summaries of the determination of a valid, invalid or inconclusive test, and copies of the chain of 

custody forms, along with the DMR for the reporting period. 

If a test is considered invalid, the permittee is required to perform additional testing during the 

monitoring period to obtain a valid test result. Failure to obtain a valid test result during the 

monitoring period shall result in a violation of the permit for failure to monitor.
 PART I

 Page 13 of 41

Permit No.: COG-840000

b. Violations of the Permit Limit, Failure of One Test Statistical Endpoint and Division Notification 

A chronic WET test is considered a violation of a permit limitation when both the NOEC and the 

IC25 are at any effluent concentration less than the IWC. The IWC for this permit has been 

determined to be 100% effluent. 

A chronic WET test is considered to have failed one of the two statistical endpoints when either the 

NOEC or the IC25 are at any effluent concentration less than the IWC. The IWC for this permit has 

been determined to be 100% effluent.

In the event of a permit violation, or when two consecutive reporting periods have resulted in failure 

of one of the two statistical endpoints (regardless of which statistical endpoints are failed), the 

permittee must provide written notification to the Division. Such notification should explain 

whether it was a violation or two consecutive failures of a single endpoint, and must indicate 

whether accelerated testing or a Toxicity Identification Evaluation or Toxicity Reduction Evaluation 

(TIE or TRE) is being performed, unless otherwise exempted, in writing, by the Division. 

Notification must be received by the Division within 14 calendar days of the permittee 

receiving notice of the WET testing results. 

c. Automatic Compliance Response 

The permittee is responsible for implementing the automatic compliance response provisions of this 

permit when one of the following occurs:

there is a violation of the permit limit (both the NOEC and the IC25 endpoints are less than 

the applicable IWC)

two consecutive monitoring periods have resulted in failure of one of the two statistical 

endpoints (either the IC25 or the NOEC)

the permittee is otherwise informed by the Division that a compliance response is necessary

When one of the above listed events occurs, the following automatic compliance response shall 

apply. The permittee shall either: 

conduct accelerated testing using the single species found to be more sensitive

conduct a Toxicity Identification Evaluation (TIE) or a Toxicity Reduction Evaluation (TRE) 

investigation as described in Part I.A.3.b.

i. Accelerated Testing

If accelerated testing is being performed, testing will be at least once every two weeks for up to 

five tests, running only one test at a time, using only the IC25 statistical endpoint to determine if 

the test passed or failed at the appropriate IWC. Accelerated testing shall continue until; 1) two 

consecutive tests fail or three of five tests fail, in which case a pattern of toxicity has been 

demonstrated or 2) two consecutive tests pass or three of five tests pass, in which case no pattern of 

toxicity has been found. Note that the same dilution series should be used in the accelerated testing

as was used in the initial test(s) that result in the accelerated testing requirement. 
 PART I

 Page 14 of 41

Permit No.: COG-840000

If accelerated testing is required due to failure of one statistical endpoint in two consecutive 

monitoring periods, and in both of those failures it was the NOEC endpoint that was failed, then 

the NOEC shall be the only statistical endpoint used to determined whether the accelerated testing 

passed or failed at the appropriate IWC. Note that the same dilution series should be used in the 

accelerated testing as was used in the initial test(s) that result in the accelerated testing 

requirement. 

If no pattern of toxicity is found the toxicity episode is considered to be ended and routine testing 

is to resume. If a pattern of toxicity is found, a TIE/TRE investigation is to be performed. If a 

pattern of toxicity is not demonstrated but a significant level of erratic toxicity is found, the 

Division may require an increased frequency of routine monitoring or some other modified 

approach. The permittee shall provide written notification of the results within 14 calendar days of 

completion of the Pattern of Toxicity/No Toxicity demonstration. 

ii. Toxicity Identification Evaluation (TIE) or Toxicity Reduction Evaluation (TRE)

If a TIE or a TRE is being performed, the results of the investigation are to be received by the 

Division within 180 calendar days of the demonstration chronic WET in the routine test, as defined 

above, or if accelerated testing was performed, the date the pattern of toxicity is demonstrated. A 

status report is to be provided to the Division at the 60 and 120 calendar day points of the TIE or 

TRE investigation. The Division may extend the time frame for investigation where reasonable 

justification exists. A request for an extension must be made in writing and received prior to the 

180 calendar day deadline. Such request must include a justification and supporting data for such 

an extension. 

Under a TIE, the permittee may use the time for investigation to conduct a preliminary TIE (PTIE) 

or move directly into the TIE. A PTIE consists of a brief search for possible sources of WET, 

where a specific parameter(s) is reasonably suspected to have caused such toxicity, and could be 

identified more simply and cost effectively than a formal TIE. If the PTIE allows resolution of the 

WET incident, the TIE need not necessarily be conducted in its entirety. If, however, WET is not 

identified or resolved during the PTIE, the TIE must be conducted within the allowed 180 calendar 

day time frame. 

The Division recommends that the EPA guidance documents regarding TIEs be followed. If 

another method is to be used, this procedure should be submitted to the Division prior to initiating 

the TIE. 

If the pollutant(s) causing toxicity is/are identified, and is/are controlled by a permit effluent 

limitation(s), this permit may be modified upon request to adjust permit requirements regarding the 

automatic compliance response. 

If the pollutant(s) causing toxicity is/are identified, and is/are not controlled by a permit effluent 

limitation(s), the Division may develop limitations the parameter(s), and the permit may be 

reopened to include these limitations. 

If the pollutant causing toxicity is not able to be identified, or is unable to be specifically identified, 

or is not able to be controlled by an effluent limit, the permittee will be required to perform either 

item 1 or item 2 below. 
 PART I

 Page 15 of 41

Permit No.: COG-840000

l) Conduct an investigation which demonstrates actual instream aquatic life conditions 

upstream and downstream of the discharge, or identify, for Division approval, and 

conduct an alternative investigation which demonstrates the actual instream impact. This 

should include WET testing and chemical analyses of the ambient water. Depending on 

the results of the study, the permittee may also be required to identify the control program 

necessary to eliminate the toxicity and its cost. Data collected may be presented to the 

WQCC for consideration at the next appropriate triennial review of the stream standards;

2) Move to a TRE by identifying the necessary control program or activity and proceed 

with elimination of the toxicity so as to meet the WET effluent limit. 

If toxicity spontaneously disappears in the midst of a TIE, the permittee shall notify the Division 

within 10 calendar days of such disappearance. The Division may require the permittee to conduct 

accelerated testing to demonstrate that no pattern of toxicity exists, or may amend the permit to 

require an increased frequency of WET testing for some period of time. If no pattern of toxicity is 

demonstrated through the accelerated testing or the increased monitoring frequency, the toxicity 

incident response will be closed and normal WET testing shall resume.

The control program developed during a TRE consists of the measures determined to be the most 

feasible to eliminate WET. This may happen through the identification of the toxicant(s) and then 

a control program aimed specifically at that toxicant(s) or through the identification of more 

general toxicant treatability processes. A control program is to be developed and submitted to the 

Division within 180 calendar days of beginning a TRE. Status reports on the TRE are to be 

provided to the Division at the 60 and 120 calendar day points of the TRE investigation.

If toxicity spontaneously disappears in the midst of a TRE, the permittee shall notify the Division 

within 10 calendar days of such disappearance. The Division may require the permittee to conduct 

accelerated testing to demonstrate that no pattern of toxicity exists, or may amend the permit to 

require an increased frequency for some period of time. If no pattern of toxicity is demonstrated 

through the accelerated testing or the increased monitoring frequency, the toxicity incident 

response will be closed and normal WET testing shall resume.

d. Toxicity Reopener

This permit may be reopened and modified to include additional or modified numerical permit 

limitations, new or modified compliance response requirements, changes in the WET testing 

protocol, the addition of both acute and chronic WET requirements, or any other conditions related 

to the control of toxicants.

4. Compliance Schedules

Where an exisiting treatment system certified under this general permit is subject to more stringent 

effluent limitations than required under a previous discharge permit, the Permittee may be eligible 

for a schedule of compliance for meeting the new effluent limitations. All Division-approved 

compliance schedules, including interim dates and requirements, will be delineated in the 

certification.
 PART I

 Page 16 of 41

Permit No.: COG-840000

D. DEFINITIONS OF TERMS

1. "Acute Toxicity" - The acute toxicity limitation is exceeded if the LC50 is at any effluent concentration 

less than or equal to the IWC indicated in this permit. 

2. “Antidegradation limits” – See “Two (2) - Year Rolling Average”.

3. "Chronic toxicity", which includes lethality and growth or reproduction, occurs when the NOEC and 

IC25 are at an effluent concentration less than the IWC indicated in this permit. 

4. "Composite" sample is a minimum of four (4) grab samples collected at equally spaced two (2) hour 

intervals and proportioned according to flow. For a SBR type treatment system, a composite sample is 

defined as sampling equal aliquots during the beginning, middle and end of a decant period, for two 

consecutive periods during a day (if possible).

5. "Continuous" measurement, is a measurement obtained from an automatic recording device which 

continually measures the effluent for the parameter in question, or that provides measurements at 

specified intervals. 

6. "Daily Maximum limitation" for all parameters except temperature, means the limitation for this 

parameter shall be applied as an instantaneous maximum (or, for pH or DO, instantaneous minimum) 

value. The instantaneous value is defined as the analytical result of any individual sample. DMRs shall 

include the maximum (and/or minimum) of all instantaneous values within the calendar month. Any 

instantaneous value beyond the noted daily maximum limitation for the indicated parameter shall be 

considered a violation of this permit. 

7. “Daily Maximum Temperature (DM)” is defined in the Basic Standards and Methodologies for Surface 

Water 1002-31, as the highest two-hour average water temperature recorded during a given 24-hour 

period. This will be determined using a rolling 2-hour maximum temperature. If data is collected every 

15 minutes, a 2 hour maximum can be determined on every data point after the initial 2 hours of 

collection. Note that the time periods that overlap days (Wednesday night to Thursday morning) do not 

matter as the reported value on the DMR is the greatest of all the 2-hour averages.

For example data points collected at:

08:15, 08:30, 08:45, 09:00, 09:15, 09:30, 09:45, 10:00, would be averaged for a single 2 hour average 

data point

08:30, 08:45, 09:00, 09:15, 09:30, 09:45, 10:00, 10:15, would be averaged for a single 2 hour average 

data point

08:45, 09:00, 09:15, 09:30, 09:45, 10:00, 10:15, 10:30, would be averaged for a single 2 hour average 

data point

This would continue throughout the course of a calendar day. The highest of these 2 hour averages over 

a month would be reported on the DMR as the daily maximum temperature. At the end/beginning of a 

month, the collected data should be used for the month that contains the greatest number of minumtes in 

the 2-hour maximum. 
 PART I

 Page 17 of 41

Permit No.: COG-840000

Data from 11 pm to 12:59 am, would fall in the previous day. Data collected from 11:01 pm to 1:00 am 

would fall in the new month.

8. "Dissolved (D) metals fraction" is defined in the Basic Standards and Methodologies for Surface Water

1002-31, as that portion of a water and suspended sediment sample which passed through a 0.40 or 0.45 

UM (micron) membrane filter. Determinations of "dissolved" constituents are made using the filtrate. 

This may include some very small (colloidal) suspended particles which passed through the membrane 

filter as well as the amount of substance present in true chemical solution. 

9. “Geometric mean” for E. coli bacteria concentrations, the thirty (30) day and seven (7) day averages 

shall be determined as the geometric mean of all samples collected in a thirty (30) day period and the 

geometric mean of all samples taken in a seven (7) consecutive day period respectively. The geometric 

mean may be calculated using two different methods. For the methods shown, a, b, c, d, etc. are 

individual sample results, and n is the total number of samples.

Method 1:

 (1/n)

Geometric Mean = (a*b*c*d*...) "*" - means multiply

Method 2:

Geometric Mean = antilog ( [log(a)+log(b)+log(c)+log(d)+...]/n )

Graphical methods, even though they may also employ the use of logarithms, may introduce significant 

error and may not be used.

In calculating the geometric mean, for those individual sample results that are reported by the analytical 

laboratory to be "less than" a numeric value, a value of 1 should be used in the calculations. If all 

individual analytical results for the month are reported to be less than numeric values, then report "less 

than" the largest of those numeric values on the monthly DMR. Otherwise, report the calculated value.

For any individual analytical result of "too numerous to count" (TNTC), that analysis shall be considered 

to be invalid and another sample shall be promptly collected for analysis. If another sample cannot be 

collected within the same sampling period for which the invalid sample was collected (during the same 

month if monthly sampling is required, during the same week if weekly sampling is required, etc.), then 

the following procedures apply: 

i. A minimum of two samples shall be collected for coliform analysis within the next sampling 

period. 

ii. If the sampling frequency is monthly or less frequent: For the period with the invalid sample 

results, leave the spaces on the corresponding DMR for reporting coliform results empty and 

attach to the DMR a letter noting that a result of TNTC was obtained for that period, and explain 

why another sample for that period had not been collected. 

If the sampling frequency is more frequent than monthly: Eliminate the result of TNTC from any further 

calculations, and use all the other results obtained within that month for reporting purposes. Attach a 
 PART I

 Page 18 of 41

Permit No.: COG-840000

letter noting that a result of TNTC was obtained, and list all individual analytical results and 

corresponding sampling dates for that month. 

10. "Grab" sample, is a single "dip and take" sample so as to be representative of the parameter being 

monitored. 

11. "In-situ" measurement is defined as a single reading, observation or measurement taken in the field at the 

point of discharge. 

12. "Instantaneous" measurement is a single reading, observation, or measurement performed on site using 

existing monitoring facilities. 

13. “Maximum Weekly Average Temperature (MWAT)” is defined in the Basic Standards and 

Methodologies for Surface Water 1002-31, as an implementation statistic that is calculated from field 

monitoring data. The MWAT is calculated as the largest mathematical mean of multiple, equally 

spaced, daily temperatures over a seven-day consecutive period, with a minimum of three data points 

spaced equally through the day. For lakes and reservoirs, the MWAT is assumed to be equivalent to the 

maximum WAT from at least three profiles distributed throughout the growing season (generally JulySeptember). 

The MWAT is calculated by averaging all temperature data points collected during a calendar day, and 

then averaging the daily average temperatures for 7 consecutive days. This 7 day averaging period is a 

rolling average, i.e. on the 8th day, the MWAT will be the averages of the daily averages of days 2-8. 

The value to be reported on the DMR is the highest of all the rolling 7-day averages throughout the 

month. For those days that are at the end/beginning of the month, the data shall be reported for the 

month that contains 4 of the 7 days.

Day 1: Average of all temperature data collected during the calendar day.

Day 2: Average of all temperature data collected during the calendar day.

Day 3: Average of all temperature data collected during the calendar day.

Day 4: Average of all temperature data collected during the calendar day.

Day 5: Average of all temperature data collected during the calendar day.

Day 6: Average of all temperature data collected during the calendar day.

Day 7: Average of all temperature data collected during the calendar day.

1

st MWAT Calculation as average of previous 7 days

Day 8: Average of all temperature data collected during the calendar day.

2

nd MWAT Calculation as average of previous 7 days

Day 9: Average of all temperature data collected during the calendar day.

3

rd MWAT Calculation as average of previous 7 days

14. "Potentially dissolved (PD) metals fraction” is defined in the Basic Standards and Methodologies for 

Surface Water 1002-31, as that portion of a constituent measured from the filtrate of a water and 

suspended sediment sample that was first treated with nitric acid to a pH of 2 or less and let stand for 8 

to 96 hours prior to sample filtration using a 0.40 or 0.45-UM (micron) membrane filter. Note the 

"potentially dissolved" method cannot be used where nitric acid will interfere with the analytical 

procedure used for the constituent measured. 
 PART I

 Page 19 of 41

Permit No.: COG-840000

15. “Practical Quantitation Limit (PQL)” means the minimum concentration of an analyte (substance) that 

can be measured with a high degree of confidence that the analyte is present at or above that 

concentration. The use of PQL in this document may refer to those PQLs shown in Part I.D of this 

permit or the PQLs of an individual laboratory. 

16. "Quarterly measurement frequency" means samples may be collected at any time during the calendar 

quarter if a continual discharge occurs. If the discharge is intermittent, then samples shall be collected 

during the period that discharge occurs. 

17. "Recorder" requires the continuous operation of a chart and/or totalizer (or drinking water rotor meters 

or pump hour meters where previously approved.) 

18. SAR and Adjusted SAR - The equation for calculation of SAR-adj is:

2

Ca Mg

Na SAR-adj 

x

Where:

Na+ = Sodium in the effluent reported in meq/l 

Mg++ = Magnesium in the effluent reported in meq/l 

Cax = calcium (in meq/l) in the effluent modified due to the ratio of bicarbonate to calcium 

The values for sodium (Na+), calcium (Ca++), bicarbonate (HCO3

-

) and magnesium (Mg++) in this 

equation are expressed in units of milliequivalents per liter (meq/l). Generally, data for these parameters 

are reported in terms of mg/l, which must then be converted to calculate the SAR. The conversions are:

meq/l = 

Equivalent weight in mg meq

Concentration in mg l

/

/

Where the equivalent weights are determined based on the atomic weight of the element divided by the 

ion’s charge: 

Na+= 23.0 mg/meq (atomic weight of 23, charge of 1)

Ca++ = 20.0 mg/meq (atomic weight of 40.078, charge of 2)

Mg++ = 12.15 mg/meq (atomic weight of 24.3, charge of 2)

HCO3

-

= 61 mg/mep (atomic weight of 61, charge of 1)

The EC and the HCO3

-

/Ca++ ratio in the effluent (calculated by dividing the HCO3

-

in meq/l by the Ca++ 

in meq/l) are used to determine the Cax using the following table. 

Table – Modified Calcium Determination for Adjusted Sodium Adsorption Ratio 

HCO3/Ca Ratio And EC 1, 

2

, 

3

Salinity of Effluent (EC)(dS/m)

0.1 0.2 0.3 0.5 0.7 1.0 1.5 2.0 3.0 4.0 6.0 8.0
 PART I

 Page 20 of 41

Permit No.: COG-840000

Ratio of 

HCO3/Ca

.05 13.20 13.61 13.92 14.40 14.79 15.26 15.91 16.43 17.28 17.97 19.07 19.94

.10 8.31 8.57 8.77 9.07 9.31 9.62 10.02 10.35 10.89 11.32 12.01 12.56

.15 6.34 6.54 6.69 6.92 7.11 7.34 7.65 7.90 8.31 8.64 9.17 9.58

.20 5.24 5.40 5.52 5.71 5.87 6.06 6.31 6.52 6.86 7.13 7.57 7.91

.25 4.51 4.65 4.76 4.92 5.06 5.22 5.44 5.62 5.91 6.15 6.52 6.82

.30 4.00 4.12 4.21 4.36 4.48 4.62 4.82 4.98 5.24 5.44 5.77 6.04

.35 3.61 3.72 3.80 3.94 4.04 4.17 4.35 4.49 4.72 4.91 5.21 5.45

.40 3.30 3.40 3.48 3.60 3.70 3.82 3.98 4.11 4.32 4.49 4.77 4.98

.45 3.05 3.14 3.22 3.33 3.42 3.53 3.68 3.80 4.00 4.15 4.41 4.61

.50 2.84 2.93 3.00 3.10 3.19 3.29 3.43 3.54 3.72 3.87 4.11 4.30

.75 2.17 2.24 2.29 2.37 2.43 2.51 2.62 2.70 2.84 2.95 3.14 3.28

1.00 1.79 1.85 1.89 1.96 2.01 2.09 2.16 2.23 2.35 2.44 2.59 2.71

1.25 1.54 1.59 1.63 1.68 1.73 1.78 1.86 1.92 2.02 2.10 2.23 2.33

1.50 1.37 1.41 1.44 1.49 1.53 1.58 1.65 1.70 1.79 1.86 1.97 2.07

1.75 1.23 1.27 1.30 1.35 1.38 1.43 1.49 1.54 1.62 1.68 1.78 1.86

2.00 1.13 1.16 1.19 1.23 1.26 1.31 1.36 1.40 1.48 1.54 1.63 1.70

2.25 1.04 1.08 1.10 1.14 1.17 1.21 1.26 1.30 1.37 1.42 1.51 1.58

2.50 0.97 1.00 1.02 1.06 1.09 1.12 1.17 1.21 1.27 1.32 1.40 1.47

3.00 0.85 0.89 0.91 0.94 0.96 1.00 1.04 1.07 1.13 1.17 1.24 1.30

3.50 0.78 0.80 0.82 0.85 0.87 0.90 0.94 0.97 1.02 1.06 1.12 1.17

4.00 0.71 0.73 0.75 0.78 0.80 0.82 0.86 0.88 0.93 0.97 1.03 1.07

4.50 0.66 0.68 0.69 0.72 0.74 0.76 0.79 0.82 0.86 0.90 0.95 0.99

5.00 0.61 0.63 0.65 0.67 0.69 0.71 0.74 0.76 0.80 0.83 0.88 0.93

7.00 0.49 0.50 0.52 0.53 0.55 0.57 0.59 0.61 0.64 0.67 0.71 0.74

10.00 0.39 0.40 0.41 0.42 0.43 0.45 0.47 0.48 0.51 0.53 0.56 0.58

20.00 0.24 0.25 0.26 0.26 0.27 0.28 0.29 0.30 0.32 0.33 0.35 0.37

30.00 0.18 0.19 0.20 0.20 0.21 0.21 0.22 0.23 0.24 0.25 0.27 0.28

1 Adapted from Suarez (1981).

2 Assumes a soil source of calcium from lime (CaCO3) or silicates; no precipitation of magnesium, and 

partial pressure of CO2 near the soil surface (PCO2) is 0.0007 atmospheres.

3 Cax, HCO3, Ca are reported in meq/l; EC is in dS/m (deciSiemens per meter).

Because values will not always be quantified at the exact EC or HCO3

–

/Ca++ ratio in the table, the 

resulting Cax must be determined based on the closest value to the calculated value. For example, for a 

calculated EC of 2.45 dS/m, the column for the EC of 2.0 would be used. However, for a calculated EC 

of 5.1, the corresponding column for the EC of 6.0 would be used. Similarly, for a HCO3

–

/Ca++ ratio of 

25.1, the row for the 30 ratio would be used.

The Division acknowledges that some effluents may have electrical conductivity levels that fall outside 

of this table, and others have bicarbonate to calcium ratios that fall outside this table. For example, 

some data reflect HCO3

–

/Ca++ ratios greater than 30 due to bicarbonate concentrations reported greater 

than 1000 mg/l versus calcium concentrations generally less than 10 mg/l (i.e., corresponding to HCO3

–

/Ca++ ratios greater than 100). Despite these high values exceeding the chart’s boundaries, it is noted 
 PART I

 Page 21 of 41

Permit No.: COG-840000

that the higher the HCO3

–

/Ca++ ratio, the greater the SAR-adj. Thus, using the Cax values corresponding 

to the final row containing bicarbonate/calcium ratios of 30, the permittee will actually calculate an 

SAR-adj that is less than the value calculated if additional rows reflecting HCO3

–

/Ca++ ratios of greater 

than 100 were added. 

19. "Seven (7) day average" means, with the exception of fecal coliform or E. coli bacteria (see geometric 

mean), the arithmetic mean of all samples collected in a seven (7) consecutive day period. Such seven 

(7) day averages shall be calculated for all calendar weeks, which are defined as beginning on Sunday 

and ending on Saturday. If the calendar week overlaps two months (i.e. the Sunday is in one month and 

the Saturday in the following month), the seven (7) day average calculated for that calendar week shall 

be associated with the month that contains the Saturday. Samples may not be used for more than one (1) 

reporting period. (See the “Analytical and Sampling Methods for Monitoring and Reporting 

Section in Part I.D.3 for guidance on calculating averages and reporting analytical results that are 

less than the PQL).

20. "Thirty (30) day average" means, except for fecal coliform or E. coli bacteria (see geometric mean), the 

arithmetic mean of all samples collected during a thirty (30) consecutive-day period. The permittee shall 

report the appropriate mean of all self-monitoring sample data collected during the calendar month on 

the Discharge Monitoring Reports. Samples shall not be used for more than one (1) reporting period. 

(See the “Analytical and Sampling Methods for Monitoring and Reporting Section in Part I.D.3 

for guidance on calculating averages and reporting analytical results that are less than the PQL).

21. Toxicity Identification Evaluation (TIE) is a set of site-specific procedures used to identify the specific 

chemical(s) causing effluent toxicity. 

22. “Total Inorganic Nitrogen (T.I.N.)” is an aggregate parameter determined based on ammonia, nitrate and 

nitrite concentrations. To determine T.I.N. concentrations, the facility must monitor for total ammonia 

and total nitrate plus nitrite (or nitrate and nitrite individually) on the same days. The calculated T.I.N. 

concentrations in mg/L shall then be determined as the sum of the analytical results of same-day 

sampling for total ammonia (as N) in mg/L, and total nitrate plus nitrite (as N) in mg/L (or nitrate as N 

and nitrite as N individually). From these calculated T.I.N. concentrations, the daily maximum and 

thirty (30) day average concentrations for T.I.N. shall be determined in the same manner as set out in the 

definitions for the daily maximum and thirty (30) day average. (See the “Analytical and Sampling 

Methods for Monitoring and Reporting Section in Part I.D.5 for guidance on calculating averages 

and reporting analytical results that are less than the PQL).

23. "Total Metals" means the concentration of metals determined on an unfiltered sample following 

vigorous digestion (Section 4.1.3), or the sum of the concentrations of metals in both the dissolved and 

suspended fractions, as described in Manual of Methods for Chemical Analysis of Water and Wastes, 

U.S. Environmental Protection Agency, March 1979, or its equivalent. 

24. “Total Recoverable Metals” means that portion of a water and suspended sediment sample measured by 

the total recoverable analytical procedure described in Methods for Chemical Analysis of Water and 

Wastes, U.S. Environmental Protection Agency, March 1979 or its equivalent. 

25. Toxicity Reduction Evaluation (TRE) is a site-specific study conducted in a step-wise process to identify 

the causative agents of effluent toxicity, isolate the source of toxicity, evaluate the effectiveness of 
 PART I

 Page 22 of 41

Permit No.: COG-840000

toxicity control options, and then confirm the reduction in effluent toxicity after the control measures are 

put in place.

26. "Twenty four (24) hour composite" sample is a combination of at least eight (8) sample aliquots of at 

least 100 milliliters, collected at equally spaced intervals during the operating hours of a facility over a 

twenty-four (24) hour period. For volatile pollutants, aliquots must be combined in the laboratory 

immediately before analysis. The composite must be flow proportional; either the time interval between 

each aliquot or the volume of each aliquot must be proportional to either the wastewater or effluent flow 

at the time of sampling or the total wastewater or effluent flow since the collection of the previous 

aliquot. Aliquots may be collected manually or automatically. 

27. "Twice Monthly" monitoring frequency means that two samples shall be collected each calendar month 

on separate weeks with at least one full week between the two sample dates. Also, there shall be at least 

one full week between the second sample of a month and the first sample of the following month. 

28. “Two (2) -Year Rolling Average” - Antidegradation limits apply as the average of all data collected in a 

two (2) year (24-month) period. These limits become effective upon the effective date of the permit, but 

are not reportable on a DMR until two years (typically 24 months) of data have been collected. After 

data has been collected for 24 months, the 30-day averages for each month are then averaged together to 

determine the two-year rolling average (using data from month 1 to month 24, then month 2 to month 

25, month 3 to month 26, etc). 

For ammonia, two-year rolling averages may be set up for individual months, or may be grouped 

together for several months. For individual months (every month has a different two-year rolling 

average limit) the two-year average is reportable after two months of data are collected. 

Example: Permit is effective Jan 2010 and there is a two-year rolling average limit specific to the 

month of January.

Jan 2010 DMR – Nothing to Report

Jan 2011 DMR – 2-Year Average of Jan 2010 and Jan 2011

Jan 2012 DMR – 2-Year Average of Jan 2011 and Jan 2012, etc.

Where several months have the same two-year average limit, it is reportable on the DMR after two 

months of data have been collected for every month in the group. 

Example: Permit is effective Jan 2010 and there is a two-year rolling average limit specific to the 

months of Jan, Feb, 

June.

1

st Reportable DMR – June 2011 - 2-Year Average Jan 2010 Feb 2010 June 2010 Jan 2011 Feb 2011 

June 2011

2

nd Reportable DMR – Jan 2012 - 2-Year Average Feb 2010 June 2010 Jan 2011 Feb 2011 June 

2011 Jan 2012

 3

rd Reportable DMR – Feb 2012 - 2-Year Average June 2010 Jan 2011 Feb 2011 June 2011 Jan 

2012 Feb 2012, etc.
 PART I

 Page 23 of 41

Permit No.: COG-840000

(See the “Analytical and Sampling Methods for Monitoring and Reporting Section in Part I.D.3 

for guidance on calculating averages and reporting analytical results that are less than the PQL).

29. "Visual" observation is observing the discharge to check for the presence of a visible sheen or floating 

oil. 

30. "Water Quality Control Division" or "Division" means the state Water Quality Control Division as 

established in 25-8-101 et al.) 

Additional relevant definitions are found in the Colorado Water Quality Control Act, CRS §§ 25-8-101 

et seq., the Colorado Discharge Permit System Regulations, Regulation 61 (5 CCR 1002-61) and other 

applicable regulations.

E. GENERAL MONITORING, SAMPLING AND REPORTING REQUIREMENTS

1. Routine Reporting of Data

Reporting of the data gathered in compliance with Part I.A or Part I.B shall be on a monthly basis. 

Reporting of all data gathered shall comply with the requirements of Part I.D. (General Requirements). 

Monitoring results shall be summarized for each calendar month and reported on Division approved 

discharge monitoring report (DMR) forms (EPA form 3320-1). 

The permittee must submit these forms either by mail, or by using the Division’s Net-DMR service 

(when available). If mailed, one form shall be mailed to the Division, as indicated below, so that the 

DMR is received no later than the 28th day of the following month (for example, the DMR for the first 

calendar quarter must be received by the Division by April 28th). If no discharge occurs during the 

reporting period, "No Discharge" shall be reported.

The original signed copy of each discharge monitoring report (DMR) shall be submitted to the Division 

at the following address: 

Colorado Department of Public Health and Environment

Water Quality Control Division

WQCD-P-B2

4300 Cherry Creek Drive South

Denver, Colorado 80246-1530

The Discharge Monitoring Report forms shall be filled out accurately and completely in accordance with 

requirements of this permit and the instructions on the forms. They shall be signed by an authorized 

person as identified in Part I.D.8.

2. Representative Sampling

Samples and measurements taken as required herein shall be representative of the volume and nature of 

the monitored discharge. All samples shall be taken at the monitoring points specified in this permit 

and, unless otherwise specified, before the effluent joins or is diluted by any other wastestream, body of 

water, or substance. Monitoring points shall not be changed without notification to and approval by the 

Division.
 PART I

 Page 24 of 41

Permit No.: COG-840000

3. Analytical and Sampling Methods for Monitoring and Reporting

The permittee shall install, calibrate, use and maintain monitoring methods and equipment, including 

biological and indicated pollutant monitoring methods. All sampling shall be performed by the 

permittee according to specified methods in 40 C.F.R. Part 136; methods approved by EPA pursuant to 

40 C.F.R. Part 136; or methods approved by the Division, in the absence of a method specified in or 

approved pursuant to 40 C.F.R. Part 136 (see text below for specifics on nonylphenol monitoring). 

If the permit contains a numeric effluent limit for a parameter, the analytical method and PQL 

selected for all monitoring conducted in accordance with this permit for that parameter shall be 

the one that can measure at or below the numeric effluent limit. If all specified analytical methods 

and corresponding PQLs are greater than the numeric effluent limit, then the analytical method 

with the lowest PQL shall be used. 

If the permit contains a report only requirement for a parameter, the analytical method and PQL 

chosen shall be one that can measure at or below the potential numeric effluent limit(s) (maximum 

allowable pollutant concentration as shown in the WQA or fact sheet). If all analytical methods 

and corresponding PQLs are greater than the potential numeric effluent limit (s), then the 

analytical method with the lowest PQL shall be used. 

If the permit contains an interim effluent limitation (a limit is report until such time as a numeric 

effluent limit becomes effective) for a parameter, the analytical method and PQL chosen for all 

monitoring conducted in accordance with this permit for the parameter shall be one that can 

measure to the final numeric effluent limit. If all analytical methods and corresponding PQLs are 

greater than the final numeric effluent limit (s), then the analytical method with the lowest PQL 

shall be used. 

For parameters such as TIN, the analytical methods chosen shall be those that can measure to the 

potential or final numeric effluent limit, based on the sum of the PQLs for nitrate, nitrite and 

ammonia.

When the analytical method which complies with the above requirements has a PQL greater than 

the permit limit, and the permittee’s analytical result is less than the PQL, the permittee shall 

report "BDL" on the DMR. Such reports will not be considered as violations of the permit limit, 

as long as the lowest available PQL is used for the analysis. When the analytical method which 

complies with the above requirements has a PQL that is equal to or less than the permit limitation, 

and the permittee’s analytical result is less than the PQL, “< X” (where X = the actual PQL 

achieved by the laboratory) shall be reported on the DMR. For parameters that have a report 

only limitation, and the permittee’s analytical result is less than the PQL, “< X” (where X = the 

actual PQL achieved by the laboratory) shall be reported on the DMR. 

In the calculation of average concentrations (i.e. 7- day average, 30-day average, 2-year rolling average) 

any individual analytical result that is less than the PQL shall be considered to be zero for the calculation 

purposes. When reporting:

If all individual analytical results are less than the PQL, the permittee shall report either “BDL” or 

“<X” (where X = the actual PQL achieved by the laboratory), following the guidance above.
 PART I

 Page 25 of 41

Permit No.: COG-840000

If one or more individual results is greater than the PQL, an average shall be calculated and reported. 

Note that it does not matter if the final calculated average is greater or less than the PQL, it must be 

reported as a value.

Note that when calculating T.I.N. for a single sampling event, any value less than the PQL (for total 

ammonia, total nitrite, or total nitrate) shall be treated as zero. The T.I.N. concentration for a single 

sampling event shall then be determined as the sum of the analytical results (zeros if applicable) of 

same day sampling for total ammonia and total nitrite and total nitrate. From these calculated T.I.N. 

concentrations, the daily maximum and thirty day average concentrations shall be calculated and 

must be reported as a value.

The present lowest PQLs for specific parameters, as determined by the State Laboratory (November 

2008) are provided below. If the analytical method cannot achieve a PQL that is less than or equal to the 

permit limit, then the method, or a more precise method, must achieve a PQL that is less than or equal to 

the PQL in the table below. A listing of the PQLs for organic parameters that must meet the above 

requirement can be found in the Division’s Practical Quantitation Limitation Guidance Document, July 

2008. 

For nonylphenol, until such time as there is an EPA 40 CFR Part 136 method, the State is 

approving use of ASTM Methods D7065 and D7485. Until a statewide PQL has been developed, 

the permittee shall use either the default PQLs listed in the table below, or develop their own sitespecific PQL in accordance with the Practical Quantitation Limitation Guidance Document (July 

2008) for Organic Parameters. This document is available on the Division’s website at 

www.coloradowaterpermits.com . The delayed effective date for the monitoring requirement 

allows time for the permittee to develop a site-specific PQL.

These limits apply to the total recoverable or the potentially dissolved fraction of metals.

For hexavalent chromium, samples must be unacidified so dissolved concentrations will be measured 

rather than potentially dissolved concentrations. 
 PART I

 Page 26 of 41

Permit No.: COG-840000

Parameter Practical 

Quantitation

Limits,

Parameter Practical 

Quantitation

Limits, μg/l

Aluminum 50 μg/l Mercury 0.1 μg/l

Ammonia 1 mg/l Mercury (low-level) 0.003 μg/l

Arsenic 1 μg/l Nickel 50 μg/l

Barium 5 μg/l N-Ammonia 50 μg/l

Beryllium 1 μg/l N Nitrate/Nitrite 0.5 mg/l

BOD / CBOD 1 mg/l N-Nitrate 50 μg/l

Boron 50 μg/l N-Nitrite 10 μg/l

Cadmium 1 μg/l Total Nitrogen 0.5 mg/l

Calcium 20 μg/l Phenols 100 μg/l

Chloride 2 mg/l Phosphorus 10 μg/l

Chlorine 0.1 mg/l Radium 226 1 pCi/l

Total Residual 

Chlorine

Radium 228 1 pCi/l

DPD colorimetric 0.10 mg/l Selenium 1 μg/l

Amperometric titration 0.05 mg/l Silver 0.5 μg/l

Chromium 20 μg/l Sodium 0.2 mg/l

Chromium, Hexavalent 20 μg/l Sulfate 5 mg/l

Copper 5 μg/l Sulfide 0.2 mg/l

Cyanide (Direct / 

Distilled)

10 μg/l Total Dissolved 

Solids

10 mg/l

Cyanide, WAD+A47 5 μg/l Total Suspended 

Solids

10 mg/l

Fluoride 0.1 mg/l Thallium 1 μg/l

Iron 10 μg/l Uranium 1 μg/l

Lead 1 μg/l Zinc 10 μg/l

Magnesium 20 μg/l Nonylphenol 

D7065

10 μg/l

Manganese 2 μg/l Nonylphenol 

D7485

0.33 μg/l

4. Records

The permittee shall establish and maintain records. Those records shall include the following:

a. The date, type, exact location, and time of sampling or measurements;

b. The individual(s) who performed the sampling or measurements; 

c. The date(s) the analyses were performed; 

d. The individual(s) who performed the analyses; 

e. The analytical techniques or methods used; 

f. The results of such analyses; and

g. Any other observations which may result in an impact on the quality or quantity of the discharge 

as indicated in 40 CFR 122.44 (i)(1)(iii). 
 PART I

 Page 27 of 41

Permit No.: COG-840000

The permittee shall retain for a minimum of three (3) years records of all monitoring information, 

including all original strip chart recordings for continuous monitoring instrumentation, all calibration 

and maintenance records, copies of all reports required by this permit and records of all data used to 

complete the application for this permit. This period of retention shall be extended during the course of 

any unresolved litigation regarding the discharge of pollutants by the permittee or when requested by the 

Division or EPA.

5. Flow Measuring Device

If not already a part of the permitted facility, within ninety (90) days after the effective date of the 

permit, a flow measuring device shall be installed to give representative values of effluent quantities at 

the respective discharge points. Unless specifically exempted, or modified in Part I.A of this permit, a 

flow measuring device will be applicable at all designated discharge points. 

At the request of the Division, the permittee shall show proof of the accuracy of any flow-measuring

device used in obtaining data submitted in the monitoring report. The flow-measuring device must 

indicate values within ten (10) percent of the actual flow being discharged from the facility. 

6. Signatory and Certification Requirements 

a. All reports and other information required by the Division, shall be signed and certified for 

accuracy by the permittee in accord with the following criteria: 

i) In the case of corporations, by a responsible corporate officer. For purposes of this section,

the responsible corporate officer is responsible for the overall operation of the facility from 

which the discharge described in the form originates;

ii) In the case of a partnership, by a general partner;

iii) In the case of a sole proprietorship, by the proprietor; 

iv) In the case of a municipal, state, or other public facility, by either a principal executive 

officer, or ranking elected official. For purposes of this section, a principal executive officer has 

responsibility for the overall operation of the facility from which the discharge originates;

v) By a duly authorized representative of a person described above, only if:

1) The authorization is made in writing by a person described in i, ii, iii, or iv above; 

2) The authorization specifies either an individual or a position having responsibility for 

the overall operation of the regulated facility or activity such as the position of plant manager, 

operator of a well or a well field, superintendent, position of equivalent responsibility, or an 

individual or position having overall responsibility for environmental matters for the 

company. (A duly authorized representative may thus be either a named individual or any 

individual occupying a named position); and, 

3) The written authorization is submitted to the Division. 
 PART I

 Page 28 of 41

Permit No.: COG-840000

b. If an authorization as described in this section is no longer accurate because a different individual 

or position has responsibility for the overall operation of the facility, a new authorization satisfying 

the requirements of this section must be submitted to the Division prior to or together with any 

reports, information, or applications to be signed by an authorized representative.

The permittee, or the duly authorized representative shall make and sign the following certification 

on all such documents: 

"I certify under penalty of law that this document and all attachments were prepared under my 

direction or supervision in accordance with a system designed to assure that qualified personnel 

properly gather and evaluate the information submitted. Based on my inquiry of the person or 

persons who manage the system, or those persons directly responsible for gathering the information, 

the information submitted is to the best of my knowledge and belief, true, accurate and complete. I 

am aware that there are significant penalties for submitting false information, including the 

possibility of fine and imprisonment for knowing violations." 
PART II

Page 29 of 41

 Permit No.: COG-840000

PART II

A. NOTIFICATION REQUIREMENTS

1. Notification to Parties

All notification requirements under this section shall be directed as follows:

a. Oral Notifications, during normal business hours shall be to:

Water Quality Protection Section - Industrial Compliance Program

Water Quality Control Division

Telephone: (303) 692-3500

b. Written notification shall be to: 

Water Quality Protection Section - Industrial Compliance Program

Water Quality Control Division

Colorado Department of Public Health and Environment

WQCD-WQP-B2

4300 Cherry Creek Drive South

Denver, CO 80246-1530

2. Change in Discharge

The permittee shall notify the Division, in writing, of any planned physical alterations or additions to the 

permitted facility. Notice is required only when:

a. The alteration or addition could significantly change the nature or increase the quantity of 

pollutants discharged, or;

b. The alteration or addition results in a significant change in the permittee's sludge use or disposal 

practices, and such alteration, addition, or change may justify the application of permit conditions 

that are different from or absent in the existing permit, including notification of additional use or 

disposal sites not reported pursuant to an approved land application plan. 

The permittee shall give advance notice to the Division of any planned changes in the permitted facility 

or activity which may result in noncompliance with permit requirements.

Whenever notification of any planned physical alterations or additions to the permitted facility is 

required pursuant to this section, the permittee shall furnish the Division such plans and specifications

which the Division deems reasonably necessary to evaluate the effect on the discharge, the stream, or 

ground water. If the Division finds that such new or altered discharge might be inconsistent with the 

conditions of the permit, the Division shall require a new or revised permit application and shall follow 

the procedures specified in Sections 61.5 through 61.6, and 61.15 of the Colorado Discharge Permit 

System Regulations.
PART II

Page 30 of 41

 Permit No.: COG-840000

3. Special Notifications - Definitions

a. Bypass: The intentional diversion of waste streams from any portion of a treatment facility.

b. Severe Property Damage: Substantial physical damage to property at the treatment facilities 

which causes them to become inoperable, or substantial and permanent loss of natural resources 

which can reasonably be expected to occur in the absence of a bypass. It does not mean economic 

loss caused by delays in production. 

c. Upset: An exceptional incident in which there is unintentional and temporary noncompliance 

with permit effluent limitations because of factors beyond the reasonable control of the permittee. 

An upset does not include noncompliance to the extent caused by operational error, improperly 

designed treatment facilities, inadequate treatment facilities, lack of preventative maintenance, or 

careless or improper operation. 

4. Noncompliance Notification

a. If, for any reason, the permittee does not comply with or will be unable to comply with any 

discharge limitations or standards specified in this permit, the permittee shall, at a minimum, provide 

the Division and EPA with the following information: 

i) A description of the discharge and cause of noncompliance;

ii) The period of noncompliance, including exact dates and times and/or the anticipated time 

when the discharge will return to compliance; and

iii) Steps being taken to reduce, eliminate, and prevent recurrence of the noncomplying 

discharge. 

b. The permittee shall report the following circumstances orally within twenty-four (24) hours

from the time the permittee becomes aware of the circumstances, and shall mail to the Division a 

written report containing the information requested in Part II.A.4 (a) within five (5) working days 

after becoming aware of the following circumstances: 

i) Circumstances leading to any noncompliance which may endanger health or the environment 

regardless of the cause of the incident; 

ii) Circumstances leading to any unanticipated bypass which exceeds any effluent limitations in 

the permit; 

iii) Circumstances leading to any upset which causes an exceedance of any effluent limitation in 

the permit; 

iv) Daily maximum violations for any of the pollutants limited by Part I.A of this permit and 

specified as requiring 24-hour notification. This includes any toxic pollutant or hazardous 
PART II

Page 31 of 41

 Permit No.: COG-840000

substance or any pollutant specifically identified as the method to control any toxic pollutant or 

hazardous substance. 

c. Unless otherwise indicated in this permit, the permittee shall report instances of non-compliance 

which are not required to be reported within 24-hours at the time Discharge Monitoring Reports are 

submitted. The reports shall contain the information listed in sub-paragraph (a) of this section. 

5. Other Notification Requirements

Reports of compliance or noncompliance with, or any progress reports on, interim and final requirements

contained in any compliance schedule in the permit shall be submitted no later than fourteen (14) 

calendar days following each scheduled date, unless otherwise provided by the Division.

The permittee shall notify the Division, in writing, thirty (30) calendar days in advance of a proposed 

transfer of permit as provided in Part II.B.3.

The permittee's notification of all anticipated noncompliance does not stay any permit condition.

All existing manufacturing, commercial, mining, and silvicultural dischargers must notify the Division 

as soon as they know or have reason to believe: 

a. That any activity has occurred or will occur which would result in the discharge, on a routine or 

frequent basis, of any toxic pollutant which is not limited in the permit, if that discharge will exceed 

the highest of the following "notification levels":

i) One hundred micrograms per liter (100 μg/l); 

ii) Two hundred micrograms per liter (200 μg/l) for acrolein and acrylonitrile; five hundred 

micrograms per liter (500 μg/l) for 2.4-dinitrophenol and 2-methyl-4.6-dinitrophenol; and one 

milligram per liter (1.0 mg/l) for antimony; 

iii) Five (5) times the maximum concentration value reported for that pollutant in the permit 

application in accordance with Section 61.4(2)(g). 

iv) The level established by the Division in accordance with 40 C.F.R. § 122.44(f). 

b. That any activity has occurred or will occur which would result in any discharge, on a nonroutine or infrequent basis, of a toxic pollutant which is not limited in the permit, if that discharge 

will exceed the highest of the following "notification levels":

i) Five hundred micrograms per liter (500 μg/l); 

ii) One milligram per liter (1 mg/l) for antimony; and

iii) Ten (10) times the maximum concentration value reported for that pollutant in the permit 

application.
PART II

Page 32 of 41

 Permit No.: COG-840000

iv) The level established by the Division in accordance with 40 C.F.R. § 122.44(f). 

6. Bypass Notification

If the permittee knows in advance of the need for a bypass, a notice shall be submitted, at least ten (10) 

calendar days before the date of the bypass, to the Division. The bypass shall be subject to Division 

approval and limitations imposed by the Division. Violations of requirements imposed by the Division 

will constitute a violation of this permit.

7. Upsets

a. Effect of an Upset

An upset constitutes an affirmative defense to an action brought for noncompliance with permit 

effluent limitations if the requirements of paragraph (b) of this section are met. No determination 

made during administrative review of claims that noncompliance was caused by upset, and before an 

action for noncompliance, is final administrative action subject to judicial review. 

b. Conditions Necessary for a Demonstration of Upset

A permittee who wishes to establish the affirmative defense of upset shall demonstrate through 

properly signed contemporaneous operating logs, or other relevant evidence that: 

i) An upset occurred and that the permittee can identify the specific cause(s) of the upset; and

ii) The permitted facility was at the time being properly operated and maintained; and

iii) The permittee submitted proper notice of the upset as required in Part II.A.4. of this permit 

(24-hour notice); and

iv) The permittee complied with any remedial measure necessary to minimize or prevent any 

discharge or sludge use or disposal in violation of this permit which has a reason able likelihood 

of adversely affecting human health or the environment. 

In addition to the demonstration required above, a permittee who wishes to establish the affirmative 

defense of upset for a violation of effluent limitations based upon water quality standards shall also 

demonstrate through monitoring, modeling or other methods that the relevant standards were 

achieved in the receiving water. 

c. Burden of Proof

In any enforcement proceeding the permittee seeking to establish the occurrence of an upset has the 

burden of proof. 
PART II

Page 33 of 41

 Permit No.: COG-840000

8. Discharge Point

Any discharge to the waters of the State from a point source other than specifically authorized by this 

permit is prohibited.

9. Proper Operation and Maintenance

The permittee shall at all times properly operate and maintain all facilities and systems of treatment and 

control (and related appurtenances) which are installed or used by the permittee as necessary to achieve 

compliance with the conditions of this permit. Proper operation and maintenance includes effective 

performance and adequate laboratory and process controls, including appropriate quality assurance 

procedures (40 CFR 122.41(e)). This provision requires the operation of back-up or auxiliary facilities 

or similar systems which are installed by the permittee only when necessary to achieve compliance with 

the conditions of the permit.

10. Minimization of Adverse Impact

The permittee shall take all reasonable steps to minimize or prevent any discharge of sludge use or 

disposal in violation of this permit which has a reasonable likelihood of adversely affecting human 

health or the environment. As necessary, accelerated or additional monitoring to determine the nature 

and impact of the noncomplying discharge is required.

11. Removed Substances

Solids, sludges, or other pollutants removed in the course of treatment or control of wastewaters shall be 

disposed in accordance with applicable state and federal regulations.

For all domestic wastewater treatment works, at industrial facilities, the permittee shall dispose of sludge 

in accordance with all State and Federal regulations.

12. Submission of Incorrect or Incomplete Information

Where the permittee failed to submit any relevant facts in a permit application, or submitted incorrect 

information in a permit application or report to the Division, the permittee shall promptly submit the 

relevant information which was not submitted or any additional information needed to correct any 

erroneous information previously submitted.

13. Bypass

a. Bypasses are prohibited and the Division may take enforcement action against the permittee for 

bypass, unless:

i) The bypass is unavoidable to prevent loss of life, personal injury, or severe property damage;

ii) There were no feasible alternatives to bypass such as the use of auxiliary treatment facilities, 

retention of untreated wastes, or maintenance during normal periods of equipment downtime. 

This condition is not satisfied if adequate back-up equipment should have been installed in the 
PART II

Page 34 of 41

 Permit No.: COG-840000

exercise of reasonable engineering judgment to prevent a bypass which occurred during normal 

periods of equipment downtime or preventive maintenance; and

iii) Proper notices were submitted in compliance with Part II.A.4. 

b. "Severe property damage" as used in this Subsection means substantial physical damage to the 

treatment facilities which causes them to become inoperable, or substantial and permanent loss of 

natural resources which can reasonably be expected to occur in the absence of a bypass. Severe 

property damage does not mean economic loss caused by delays in production. 

c. The permittee may allow a bypass to occur which does not cause effluent limitations to be 

exceeded, but only if it also is for essential maintenance or to assure optimal operation. These 

bypasses are not subject to the provisions of paragraph (a) above. 

d. The Division may approve an anticipated bypass, after considering adverse effects, if the 

Division determines that the bypass will meet the conditions specified in paragraph (a) above. 

14. Reduction, Loss, or Failure of Treatment Facility

The permittee has the duty to halt or reduce any activity if necessary to maintain compliance with the 

effluent limitations of the permit. Upon reduction, loss, or failure of the treatment facility, the permittee 

shall, to the extent necessary to maintain compliance with its permit, control production, control sources 

of wastewater, or all discharges, until the facility is restored or an alternative method of treatment is 

provided. This provision also applies to power failures, unless an alternative power source sufficient to 

operate the wastewater control facilities is provided.

It shall not be a defense for a permittee in an enforcement action that it would be necessary to halt or 

reduce the permitted activity in order to maintain compliance with the conditions of this permit. 

B. RESPONSIBILITIES

1. Inspections and Right to Entry

The permittee shall allow the Division and/or the authorized representative, upon the presentation of 

credentials:

a. To enter upon the permittee's premises where a regulated facility or activity is located or in which 

any records are required to be kept under the terms and conditions of this permit; 

b. At reasonable times to have access to and copy any records required to be kept under the terms 

and conditions of this permit and to inspect any monitoring equipment or monitoring method 

required in the permit; and

c. To enter upon the permittee's premises in a reasonable manner and at a reasonable time to inspect 

and/or investigate, any actual, suspected, or potential source of water pollution, or to ascertain 

compliance or non compliance with the Colorado Water Quality Control Act or any other applicable 

state or federal statute or regulation or any order promulgated by the Division. The investigation 
PART II

Page 35 of 41

 Permit No.: COG-840000

may include, but is not limited to, the following: sampling of any discharge and/or process waters, 

the taking of photographs, interviewing of any person having knowledge related to the discharge 

permit or alleged violation, access to any and all facilities or areas within the permittee's premises 

that may have any affect on the discharge, permit, or alleged violation. Such entry is also authorized 

for the purpose of inspecting and copying records required to be kept concerning any effluent source. 

d. The permittee shall provide access to the Division to sample the discharge at a point after the 

final treatment process but prior to the discharge mixing with state waters upon presentation of 

proper credentials. 

In the making of such inspections, investigations, and determinations, the Division, insofar as 

practicable, may designate as its authorized representatives any qualified personnel of the Department of 

Agriculture. The Division may also request assistance from any other state or local agency or institution.

2. Duty to Provide Information

The permittee shall furnish to the Division, within a reasonable time, any information which the 

Division may request to determine whether cause exists for modifying, revoking and reissuing, or 

terminating this permit, or to determine compliance with this permit. The permittee shall also furnish to 

the Division, upon request, copies of records required to be kept by this permit. 

3. Transfer of Ownership or Control

a. Except as provided in paragraph b. of this section, a permit may be transferred by a permittee 

only if the permit has been modified or revoked and reissued as provided in Section 61.8(8) of the 

Colorado Discharge Permit System Regulations, to identify the new permittee and to incorporate 

such other requirements as may be necessary under the Federal Act. 

b. A permit may be automatically transferred to a new permittee if: 

i) The current permittee notifies the Division in writing 30 calendar days in advance of the 

proposed transfer date; and

ii) The notice includes a written agreement between the existing and new permittee(s) 

containing a specific date for transfer of permit responsibility, coverage and liability between 

them; and

iii) The Division does not notify the existing permittee and the proposed new permittee of its 

intent to modify, or revoke and reissue the permit. 

iv) Fee requirements of the Colorado Discharge Permit System Regulations, Section 61.15, have 

been met. 

4. Availability of Reports

Except for data determined to be confidential under Section 308 of the Federal Clean Water Act and the 

Colorado Discharge Permit System Regulations 5 CCR 1002-61, Section 61.5(4), all reports prepared in 
PART II

Page 36 of 41

 Permit No.: COG-840000

accordance with the terms of this permit shall be available for public inspection at the offices of the 

Division and the Environmental Protection Agency. 

The name and address of the permit applicant(s) and permittee(s), permit applications, permits and 

effluent data shall not be considered confidential. Knowingly making false statement on any such report 

may result in the imposition of criminal penalties as provided for in Section 309 of the Federal Clean 

Water Act, and Section 25-8-610 C.R.S.

5. Modification, Suspension, Revocation, or Termination of Permits By the Division

The filing of a request by the permittee for a permit modification, revocation and reissuance, termination 

or a notification of planned changes or anticipated noncompliance, does not stay any permit condition. 

a. A permit may be modified, suspended, or terminated in whole or in part during its term for 

reasons determined by the Division including, but not limited to, the following: 

i) Violation of any terms or conditions of the permit; 

ii) Obtaining a permit by misrepresentation or failing to disclose any fact which is material to 

the granting or denial of a permit or to the establishment of terms or conditions of the permit; or

iii) Materially false or inaccurate statements or information in the permit application or the 

permit. 

iv) A determination that the permitted activity endangers human health or the classified or 

existing uses of state waters and can only be regulated to acceptable levels by permit 

modifications or termination. 

b. A permit may be modified in whole or in part for the following causes, provided that such 

modification complies with the provisions of Section 61.10 of the Colorado Discharge Permit 

System Regulations: 

i) There are material and substantial alterations or additions to the permitted facility or activity 

which occurred after permit issuance which justify the application of permit conditions that are 

different or absent in the existing permit.

ii) The Division has received new information which was not available at the time of permit 

issuance (other than revised regulations, guidance, or test methods) and which would have 

justified the application of different permit conditions at the time of issuance. For permits issued 

to new sources or new dischargers, this cause includes information derived from effluent testing 

required under Section 61.4(7)(e) of the Colorado Discharge Permit System Regulations. This 

provision allows a modification of the permit to include conditions that are less stringent than the 

existing permit only to the extent allowed under Section 61.10 of the Colorado Discharge Permit 

System Regulations. 
PART II

Page 37 of 41

 Permit No.: COG-840000

iii) The standards or regulations on which the permit was based have been changed by 

promulgation of amended standards or regulations or by judicial decision after the permit was 

issued. Permits may be modified during their terms for this cause only as follows: 

(A) The permit condition requested to be modified was based on a promulgated effluent 

limitation guideline, EPA approved water quality standard, or an effluent limitation set forth 

in 5 CCR 1002-62, § 62 et seq.; and

(B) EPA has revised, withdrawn, or modified that portion of the regulation or effluent 

limitation guideline on which the permit condition was based, or has approved a Commission 

action with respect to the water quality standard or effluent limitation on which the permit 

condition was based; and

(C) The permittee requests modification after the notice of final action by which the EPA 

effluent limitation guideline, water quality standard, or effluent limitation is revised, 

withdrawn, or modified; or

(D) For judicial decisions, a court of competent jurisdiction has remanded and stayed EPA 

promulgated regulations or effluent limitation guidelines, if the remand and stay concern that 

portion of the regulations or guidelines on which the permit condition was based and a 

request is filed by the permittee in accordance with this Regulation, within ninety (90) days 

of judicial remand. 

iv) The Division determines that good cause exists to modify a permit condition because of 

events over which the permittee has no control and for which there is no reasonable available 

remedy. 

v) The permittee has received a variance. 

vi) When required to incorporate applicable toxic effluent limitation or standards adopted 

pursuant to § 307(a) of the Federal act. 

vii) When required by the reopener conditions in the permit. 

viii)As necessary under 40 C.F.R. 403.8(e), to include a compliance schedule for the development 

of a pretreatment program. 

ix) When the level of discharge of any pollutant which is not limited in the permit exceeds the 

level which can be achieved by the technology-based treatment requirements appropriate to the 

permittee under Section 61.8(2) of the Colorado Discharge Permit System Regulations. 

x) To establish a pollutant notification level required in Section 61.8(5) of the Colorado 

Discharge Permit System Regulations. 

xi) To correct technical mistakes, such as errors in calculation, or mistaken interpretations of law 

made in determining permit conditions, to the extent allowed in Section 61.10 of the Colorado 

State Discharge Permit System Regulations. 
PART II

Page 38 of 41

 Permit No.: COG-840000

xii) When required by a permit condition to incorporate a land application plan for beneficial 

reuse of sewage sludge, to revise an existing land application plan, or to add a land application 

plan. 

xiii)For any other cause provided in Section 61.10 of the Colorado Discharge Permit System 

Regulations. 

c. At the request of a permittee, the Division may modify or terminate a permit and issue a new 

permit if the following conditions are met: 

i) The Regional Administrator has been notified of the proposed modification or termination 

and does not object in writing within thirty (30) calendar days of receipt of notification, 

ii) The Division finds that the permittee has shown reasonable grounds consistent with the 

Federal and State statutes and regulations for such modifications or termination; 

iii) Requirements of Section 61.15 of the Colorado Discharge Permit System Regulations have 

been met, and

iv) Requirements of public notice have been met. 

d. Permit modification (except for minor modifications), termination or revocation and reissuance 

actions shall be subject to the requirements of Sections 61.5(2), 61.5(3), 61.6, 61.7 and 61.15 of the 

Colorado Discharge Permit System Regulations. The Division shall act on a permit modification 

request, other than minor modification requests, within 180 calendar days of receipt thereof. Except 

for minor modifications, the terms of the existing permit govern and are enforceable until the newly 

issued permit is formally modified or revoked and reissued following public notice. 

e. Upon consent by the permittee, the Division may make minor permit modifications without 

following the requirements of Sections 61.5(2), 61.5(3), 61.7, and 61.15 of the Colorado Discharge

Permit System Regulations. Minor modifications to permits are limited to: 

i) Correcting typographical errors; or 

ii) Increasing the frequency of monitoring or reporting by the permittee; or 

iii) Changing an interim date in a schedule of compliance, provided the new date of compliance 

is not more than 120 calendar days after the date specific in the existing permit and does not 

interfere with attainment of the final compliance date requirement; or 

iv) Allowing for a transfer in ownership or operational control of a facility where the Division 

determines that no other change in the permit is necessary, provided that a written agreement 

containing a specific date for transfer of permit responsibility, coverage and liability between the 

current and new permittees has been submitted to the Division; or 
PART II

Page 39 of 41

 Permit No.: COG-840000

v) Changing the construction schedule for a discharger which is a new source, but no such 

change shall affect a discharger's obligation to have all pollution control equipment installed and 

in operation prior to discharge; or 

vi) Deleting a point source outfall when the discharge from that outfall is terminated and does 

not result in discharge of pollutants from other outfalls except in accordance with permit limits. 

f. When a permit is modified, only the conditions subject to modification are reopened. If a permit 

is revoked and reissued, the entire permit is reopened and subject to revision and the permit is 

reissued for a new term. 

g. The filing of a request by the permittee for a permit modification, revocation and reissuance or 

termination does not stay any permit condition. 

h. All permit modifications and reissuances are subject to the antibacksliding provisions set forth in 

61.10(e) through (g).

6. Oil and Hazardous Substance Liability

Nothing in this permit shall be construed to preclude the institution of any legal action or relieve the 

permittee from any responsibilities, liabilities, or penalties to which the permittee is or may be subject to 

under Section 311 (Oil and Hazardous Substance Liability) of the Clean Water Act.

7. State Laws

Nothing in this permit shall be construed to preclude the institution of any legal action or relieve the 

permittee from any responsibilities, liabilities, or penalties established pursuant to any applicable State 

law or regulation under authority granted by Section 510 of the Clean Water Act. Nothing in this permit 

shall be construed to prevent or limit application of any emergency power of the division. 

8. Permit Violations

Failure to comply with any terms and/or conditions of this permit shall be a violation of this permit. The 

discharge of any pollutant identified in this permit more frequently than or at a level in excess of that 

authorized shall constitute a violation of the permit. Except as provided in Part I.D and Part II.A or B, 

nothing in this permit shall be construed to relieve the permittee from civil or criminal penalties for 

noncompliance (40 CFR 122.41(a)(1)).

9. Property Rights

The issuance of this permit does not convey any property or water rights in either real or personal 

property, or stream flows, or any exclusive privileges, nor does it authorize any injury to private property 

or any invasion of personal rights, nor any infringement of Federal, State or local laws or regulations. 
PART II

Page 40 of 41

 Permit No.: COG-840000

10. Severability

The provisions of this permit are severable. If any provisions of this permit, or the application of any 

provision of this permit to any circumstance, is held invalid, the application of such provision to other 

circumstances and the application of the remainder of this permit shall not be affected. 

11. Renewal Application

If the permittee desires to continue to discharge, a permit renewal application shall be submitted at least 

one hundred eighty (180) calendar days before this permit expires. If the permittee anticipates there will 

be no discharge after the expiration date of this permit, the Division should be promptly notified so that 

it can terminate the permit in accordance with Part II.B.5. 

12. Confidentiality

Any information relating to any secret process, method of manufacture or production, or sales or 

marketing data which has been declared confidential by the permittee, and which may be acquired, 

ascertained, or discovered, whether in any sampling investigation, emergency investigation, or 

otherwise, shall not be publicly disclosed by any member, officer, or employee of the Commission or the 

Division, but shall be kept confidential. Any person seeking to invoke the protection of this Subsection 

(12) shall bear the burden of proving its applicability. This section shall never be interpreted as 

preventing full disclosure of effluent data. 

13. Fees

The permittee is required to submit payment of an annual fee as set forth in the 2005 amendments to the 

Water Quality Control Act. Section 25-8-502 (l) (b), and the Colorado Discharge Permit System 

Regulations 5 CCR l002-61, Section 61.l5 as amended. Failure to submit the required fee when due and 

payable is a violation of the permit and will result in enforcement action pursuant to Section 25-8-60l et. 

seq., C.R.S. l973 as amended. 

14. Duration of Permit

The duration of a permit shall be for a fixed term and shall not exceed five (5) years. Filing of a timely 

and complete application shall cause the expired permit to continue in force to the effective date of the 

new permit. The permit's duration may be extended only through administrative extensions and not 

through interim modifications. 

15. Section 307 Toxics

If a toxic effluent standard or prohibition, including any applicable schedule of compliance specified, is 

established by regulation pursuant to Section 307 of the Federal Act for a toxic pollutant which is 

present in the permittee's discharge and such standard or prohibition is more stringent than any limitation 

upon such pollutant in the discharge permit, the Division shall institute proceedings to modify or revoke 

and reissue the permit to conform to the toxic effluent standard or prohibition.
PART II

Page 41 of 41

 Permit No.: COG-840000

16. Effect of Permit Issuance

a. The issuance of a permit does not convey any property rights or any exclusive privilege. 

b. The issuance of a permit does not authorize any injury to person or property or any invasion of 

personal rights, nor does it authorize the infringement of federal, state, or local laws or regulations. 

c. Except for any toxic effluent standard or prohibition imposed under Section 307 of the Federal 

act or any standard for sewage sludge use or disposal under Section 405(d) of the Federal act, 

compliance with a permit during its term constitutes compliance, for purposes of enforcement, with 

Sections 301, 302, 306, 318, 403, and 405(a) and (b) of the Federal act. However, a permit may be 

modified, revoked and reissued, or terminated during its term for cause as set forth in Section 61.8(8) 

of the Colorado Discharge Permit System Regulations. 

d. Compliance with a permit condition which implements a particular standard for sewage sludge 

use or disposal shall be an affirmative defense in any enforcement action brought for a violation of 

that standard for sewage sludge use or disposal.