Colorado Discharge Permit System (CDPS)

Fact Sheet for Modification 3

General Permit Number COG591000 

DOMESTIC WASTEWATER TREATMENT FACILITIES THAT DISCHARGE TO RECEIVING WATERS THAT ARE:

UNCLASSIFIED; USE-PROTECTED; REVIEWABLE; OR ARE DESIGNATED

AS THREATENED AND ENDANGERED HABITAT

Kelly Drengler

August 11, 2022

TABLE OF CONTENTS

I.  TYPE OF PERMIT.......................................................................... 1

II.  FACILITY INFORMATION............................................................... 1

III.  CHANGES MADE AS A RESULT OF THE MINOR MODIFICATION......... 2

I.        TYPE OF PERMIT

1. Type of Modification: General Permit, Modification 3 - Minor Amendment,

Division-Initiated (no fee)

1. Discharge To:          Surface Water 

II.        FACILITY INFORMATION

1. SIC Code:                               4952 Sewerage Systems

1. Facility Flows:                    Less than 1.0 MGD

C.    Facilities and Discharges Covered

General Permit COG591000 (the general permit) authorizes discharges from domestic wastewater treatment plants as defined in Regulation 22 (5 CCR 1002-22): Site Location and Design Approval Regulations for Domestic Wastewater Treatment Works. The general permit also authorizes domestic discharges from facilities that accept industrial waste that are not required to develop an industrial pretreatment program pursuant to either Section 307 of the federal Clean Water Act or Section 63.9 of Regulation No. 63 (5 CCR 1002-63): Pretreatment Regulations. The general permit authorizes direct discharges to surface water and discharges to surface water via hydrologically connected groundwater. The applicant must meet all of the qualifications in Part I.A.3 of the general permit in order to qualify for coverage. 

For the purposes of this general permit, dischargers to surface water via hydrologically connected groundwater include dischargers that the division has determined must obtain surface water discharge permit coverage. This may include dischargers that were previously covered under a groundwater discharge permit and have been determined to be discharges to surface water and applied for coverage under a surface water discharge permit. 

III.        CHANGES MADE AS A RESULT OF THE MINOR MODIFICATION

The division initiated a minor modification on July 18, 2022 to clarify several sections in Parts 1.B.2-6 of the permit, and to reorganize the remaining sections. This minor modification also is intended to to address new information, in accordance with 5 CCR 1002-61, Reg. 61.8(8)(b)(ii). 

61. A typographical correction to Tables 2a – 2d have been made, in accordance with Regulation 61.8(8)(f)(i), to include a To Be Determined (TBD) designation for “Other Pollutants” in the 2-year Avg column since these unspecified parameters may also be subject to antidegradation limits.

1. A clarification in Part I.B.3 of the permit is needed so that Table 2e – EPA Recommended Periodic Pollutant Monitoring and associated text, may be applied to all certifications under the

COG591000 General Permit, and not just the Classified Water Discharges. Therefore,Table 2e and associated text became Part I.B.5 (EPA Pollutant Monitoring) of the permit. Table 2e – EPA Recommended Periodic Pollutant Monitoring became Table 8 (EPA Recommended Periodic Pollutant Monitoring).

1. Another clarification in Part I.B.3 of the permit is needed so that monitoring requirements for PFAS may be applied to all certifications under the GOG591000 General Permit, and not just the classified Water Discharges. PFAS monitoring details from Part I.B.3 were moved to a new part of the permit - Part I.B.6 (PFAS Monitoring). Additional changes to the PFAS monitoring requirements are explained below in Part III.E of this fact sheet.

1. The sections and tables following newly created I.B.4 and I.B.5 and Table 8 in the Permit Document have been renumbered due to the clarifications and reorganization discussed in modifications A and B above.

5. The division has learned that Method DoD QSM has been updated. A reference to “Method DoD QSM 5.1 or later,” was included in the COG591000 General Permit (issued date of April 30, 2022).

The most recent version of the DoD QSM is version 5.4, which was revised to incorporate EPA Draft Method 1633. Consistent with the current version of the DoD QSM method, Part I.E.5.f of the permit has been updated to require compliance with EPA Draft Method 1633.  Requiring the use of Draft Method 1633 is also consistent with Policy 20-1, which states in part (page 6):

The laboratory selected should be able to perform analysis on wastewater (nonpotable) matrices using a method that is compliant with the requirements set forth in the Department of Defense (DoD) Quality Systems Manual (QSM) for Environmental Laboratories   

Additionally, see Policy 20-1 (page 6). In its citation for the DoD QSM, Policy 20-1 states “please refer to the most up-to-date version available.”  Id. at 6 n.3. As noted in Policy 20-1, it was the Commission’s intent to require permittees use a method that is compliant with the requirements set forth in the most recent version of the Department of Defense (DoD) Quality Systems Manual (QSM) for Environmental Laboratories. 

As stated above, the most recent version of the DoD QSM (version 5.4) was revised to incorporate EPA Draft Method 1633. Therefore, EPA Draft Method 1633 is the currently required laboratory method.

EPA Draft Method 1633 currently tests 40 PFAS parameters. However, the General Permit

COG591000, issued on April 30, 2022, subsequently modified on June 2 and July 14, 2022, only listed the 25 parameters required by the method that was current at the time the permit was issued. Therefore, to ensure that facilities have all of the required parameters listed in the permit tables, and provided on DMRs and consistent with EPA Draft Method 1633, the division has removed Permit Table 2f (PFAS Monitoring Requirements) in Part I.B.2 of the permit, and has included the updated table below. 

ng/L = nanograms per liter

*The PFAS sum is calculated based on the following equation: 

PFAS Sum (ng/l) = [PFOA] (ng/l) + [PFOSA] (ng/l) + [PFNA] (ng/l) + ([NEtFOSAA] (ng/l) * 0.85) + ([NMeFOSAA] (ng/l) * 0.88) + [PFOS] (ng/l) + ([8:2 FTS] (ng/l) * 0.78)

This calculation is performed for each sampling event, and the resulting daily maximum and 30-day average results shall be reported on the discharge monitoring report submitted for the monthly monitoring period.

** The division does not currently have EPA ICIS codes for the following 4 parameters: 

EPA has not yet provided the codes for these parameters. Therefore, data for these 4 parameters cannot currently be entered into ICIS.  However, the lack of ICIS codes is not intended to indicate relief from sampling or reporting for these parameters. The division anticipates issuing a correction with the ICIS codes prior to this permit becoming effective. However, in the event the ICIS codes are delayed, reporting of these pollutants remains a requirement as indicated in the permit table(s).  Data from the analysis for these 4 parameters should be submitted to the division on blank DMRs that will be sent to the permittee, for the division to enter manually. This will continue until a division-initiated permit modification with the codes becomes effective. As this facility is using netDMR, permit modifications like ICIS codes are immediate, and data can be entered upon the effective date of the modification.

Further, in order to provide a comprehensive list of PFAS quantification limits,the PFAS

Quantification Limits table previously included in Part I.E.5 of the permit has been deleted, and an updated PFAS Quantification Limits Table is included below.  

PFAS Quantification Limits Table – Per- and Poly-fluoroalkyl substances (PFAS) 

¹ng/L = nanograms per liter  

The following changes were also made to the permit:

The following PFAS Monitoring text (previously included in Part I.B.3 of the permit document):

“A one-time monitoring requirement for PFAS will be included in the certification to gather information on the presence of this substance in the effluent discharge.  The specific monitoring requirements are shown in Table 2f below. Please note that due to reporting system limitations, the frequency listed in the certification will be “annual”, however for each year the facility does not sample for PFAS parameters, the permittee should enter “Code 9 - Conditional Monitoring – Not Required this Period” into NetDMR for these parameters. Leaving these parameters blank in NetDMR will trigger a non-compliance violation.”

Has been updated in the new Part I.B.6 (PFAS Monitoring) of the permit document to the following text:

“A one-time monitoring requirement for PFAS will be included in the certification to gather information on the presence of this substance in the effluent discharge.  

Please note that due to reporting system limitations, the frequency listed in the certification will be “annual”, however for each year the facility does not sample for PFAS parameters, the permittee should enter “Code 9 - Conditional Monitoring – Not Required this Period” into NetDMR for these parameters. Leaving these parameters blank in NetDMR will trigger a non-compliance violation.”   

The PFAS Analysis section in Part I.E.5.f of the previous permit document was updated from the following :

“At the time of permit issuance, there is no EPA-approved analytical method for analyzing PFAS in wastewaters (non-potable) that are approved for Clean Water Act monitoring in accordance with 40 CFR Part 136 (Appendix B). The analytical method for the parameters in the table below shall be compliant with the requirements set forth in the Department of Defense (DoD) Quality Systems Manual (QSM) for Environmental Laboratories (DoD QSM 5.1 or later [Table B-15: Per- and Polyfluoroalkyl Substances (PFAS) Using Liquid Chromatography Tandem Mass] Spectrometry (LC/MS/MS) With Isotope Dilution or Internal Standard Quantification in Matrices Other Than Drinking Water]). 

At a minimum, the laboratory selected shall be able to analyze and quantify the PFAS listed in Table 2 at or below the associated PFAS quantification limits (PFAS QL). If the laboratory selected is capable of achieving a quantification limit for a specific PFAS that is lower than the PFAS QL listed below, analytical results should be reported to the department relative to the lower laboratory quantification limit, and not reported as “less than” the PFAS QL in the table below.

Any 40 CFR Part 136 (Appendix B) approved method for analyzing PFAS in wastewater that becomes available in the future would replace this current analytical method requirement.”

The updated text is as follows:

“At the time of permit issuance, there is no EPA-approved analytical method for analyzing PFAS in wastewaters (non-potable) that are approved for Clean Water Act monitoring in accordance with 40 CFR Part 136 (Appendix B). The analytical method for the PFAS parameters shall be compliant with the requirements set forth in the Department of Defense (DoD) Quality Systems Manual (QSM) for Environmental Laboratories, currently DoD QSM 5.4. DoD QSM 5.4 in turn requires compliance with EPA Draft Method 1633.

At a minimum, the laboratory selected shall be able to analyze and quantify the PFAS parameters at or below the associated PFAS quantification limits (PFAS QL). If the laboratory selected is capable of achieving a quantification limit for a specific PFAS that is lower than the PFAS QL listed below, analytical results should be reported to the department relative to the lower laboratory quantification limit, and not reported as “less than” the PFAS QL in the table below.

Any 40 CFR Part 136 (Appendix B) approved method for analyzing PFAS in wastewater that becomes available in the future would replace this current analytical method requirement.”

 Part III: Table V “Toxic Pollutants and Hazardous Substances Required To Be Identified by Existing Dischargers if Expected To Be Present” has been updated with the additional 15 PFAS parameters. 

These actions eliminate the need to modify the permit in the event there is a change to the method that results in different quantification limits.