General Permit Certification.pdf

4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe/wqcd

CERTIFICATION TO DISCHARGE UNDER CDPS GENERAL PERMIT COG591000

MINOR DOMESTIC WASTEWATER TREATMENT FACILITIES DISCHARGING TO RECEIVING WATERS THAT ARE:

UNCLASSIFIED; USE-PROTECTED; REVIEWABLE; OR ARE DESIGNATED

AS THREATENED AND ENDANGERED SPECIES HABITAT

Certification Number: COG591156

This Certification to Discharge specifically authorizes:

Lyons Town of to discharge from the facility identified as

Lyons WWTF to: St Vrain River

Eligibility Category:

Mechanical Facilities With Design Flows Of Greater Than 0.25 MGD and Less Than

1.0 MGD

Facility Address: 198 2nd Ave, Lyons, CO 80540, Boulder County

Facility Latitude/Longitude: 40.219811 Latitude, -105.264167 Longitude

Permitted Feature 001A External Outfall

40.215278 Latitude, -105.259444 Longitude following disinfection prior to entering the receiving water(s)

Permitted Feature 300I Influent Sampling Location

At a representative location prior to chemical, physical, or biological treatment

Permitted Feature UST1A Instream Ambient

40.215543 Latitude, -105.259387 Longitude Upstream from the facility discharge to collect continuous ambient temperature data

The hydraulic and organic capacities, in this certification, are 0.3065 MGD and 1,535 lbs BOD5/day, respectively. These values are based on Site Approval number 4289 for this WWTF.

Permit Limitations and Monitoring Requirements apply consistent with the Permit Part I.B and Part I.C. The specific requirements that apply to this facility are outlined below.

Mechanical Facilities With Design Flows Of Greater Than 0.25 MGD and Less Than 1.0 MGD Discharging to Classified Waters

Permitted Feature ID: 300I Permitted Feature Type: Influent Structure for Mechanical WWTF > 0.25 MGD and <1 MGD Limit Set: 2

Mechanical Facilities With Design Flows Of Greater Than 0.25 MGD and Less Than 1.0 MGD Discharging to Classified Waters

ICIS

Code

Parameter Influent Monitoring Monitoring

Frequency1 Sample Type

30-Day Avg.

7-Day Avg.

Daily Max.

50050G Flow, MGD Report Report Continuous2 Recorder2

00180P Plant Capacity (% of Hydraulic Capacity)3 Report Monthly Calculated3

00310G BOD5, mg/l Report Report Weekly Composite4

00310G BOD5, lbs/day Report Report Weekly Calculated

00180Q Plant Capacity (% of Organic Capacity)3 Report Monthly Calculated3

00530G Total Suspended Solids, mg/l Report Report Weekly Composite4 The hydraulic and organic capacities, applicable to Part I.B of this permit, are 0.3065 MGD and 1,535 lbs BOD5/day, respectively. These values are based on Site Approval number 4289.

1 Monitoring frequency reductions may be granted, in accordance with the Baseline Monitoring Frequency, Sample Type, and Reduced Monitoring Frequency Policy for Industrial and Domestic Wastewater Treatment Facilities (WQP-20).

2 The monitoring frequency and sample type for effluent flow is specified in the certification and is fully enforceable under this permit. Mechanical type treatment facilities are typically required to have both influent and effluent flow measuring and recording devices. This requirement may be waived in cases where the division determines that either influent or effluent flow measurements are impractical. For these facilities, flow measuring and sampling type will be specified in the certification. If only one device is applicable, then that device will be used to report both influent and effluent flow. However, where these devices are not in place at the time of certification, the permittee has one year from the end of the calendar month that certification was given to install the required equipment. Where such equipment is in place, the frequency and type of flow monitoring will be "Continuous" and "Recorder", respectively.

Where such equipment is not in place, the frequency and type of flow monitoring, during the interim period, will be specified in the certification. For certain facilities, the use of a metered pumping rate or potable water use or may be allowed. In these cases, the monitoring frequency and sample type will be determined and specified in the certification.

3 The % capacity is to be reported against the listed capacities for the design capacity and for the organic capacities as noted in the most recent Site Approval and as listed in the certification. The percentage should be calculated using the 30-day average values divided by the corresponding capacity, times 100.

4 See the definition of “composite” in Part I.D of this permit. If the division determines that a flow-weighted composite sample is impracticable for a facility, a time composite sample of four equal aliquots collected at two-hour intervals or sampling equal aliquots will be allowed. The monitoring frequency and sample type will be specified in the certification.

See Section VI.A of the fact sheet for more information.

Permitted Feature ID: 001A Permitted Feature Type: External Outfall for Mechanical WWTF > 0.25 MGD and <1 MGD Limit Set: 2

Mechanical Facilities with Design Flows Greater Than 0.25 MGD and Less Than 1.0 MGD Discharging to Classified Waters

ICIS

Code

Parameter Limitation Sampling

30-day Avg. 7-day Avg. Daily Max Frequency1 Type2

50050 Flow, MGD3 0.3065 Report Continuous4 Recorder4

00310 BOD5, mg/l 30 45 Weekly Composite

81010 BOD5, percent removal 85% (min) Weekly Calculated

00530 Total Suspended Solids, mg/l 30 45 Weekly Composite

81011 TSS, percent removal 85% (min) Weekly Calculated

00400 pH, s.u. 6.5-9.0 Daily Grab

84066 Oil and Grease, mg/l Report Daily Visual

03582 Oil and Grease, mg/l 10 Contingent Grab

51040 E. coli, no/100 ml5 126 252 Weekly Grab

50060 Total Residual Chlorine, mg/l 0.022 0.019 3 Days / Week Grab

00640 Total Inorganic Nitrogen 15 Weekly Composite

00615 Total Nitrite, mg/l Report Weekly Composite

00610 Total Ammonia, mg/l as N Jan 4.3 16 Weekly Composite

00610 Total Ammonia, mg/l as N Feb 4.5 18 Weekly Composite

00610 Total Ammonia, mg/l as N Mar 3.7 15 Weekly Composite

00610 Total Ammonia, mg/l as N Apr 3.3 14 Weekly Composite

00610 Total Ammonia, mg/l as N May 3.5 15 Weekly Composite

00610 Total Ammonia, mg/l as N Jun 3.6 16 Weekly Composite

00610 Total Ammonia, mg/l as N Jul 3.0 17 Weekly Composite

00610 Total Ammonia, mg/l as N Aug 3.2 18 Weekly Composite

00610 Total Ammonia, mg/l as N Sept 3.8 17 Weekly Composite

00610 Total Ammonia, mg/l as N Oct 4.0 15 Weekly Composite

00610 Total Ammonia, mg/l as N Nov 4.1 15 Weekly Composite

00610 Total Ammonia, mg/l as N Dec 4.0 15 Weekly Composite

00010 Temp Daily Max, April-Oct (°C) Report Continuous Recorder

00010 Temp Daily Max, Nov-March (°C) Report Continuous Recorder

00010 Temp MWAT, April-Oct (°C) Report Continuous Recorder

00010 Temp MWAT, Nov-March (°C) Report Continuous Recorder

00978 As, TR (μg/l), until 12/31/2027 1.0 Monthly Composite

00978 As, TR (μg/l), beginning 1/1/2028 0.02 Monthly Composite

Mechanical Facilities with Design Flows Greater Than 0.25 MGD and Less Than 1.0 MGD Discharging to Classified Waters

ICIS

Code

Parameter Limitation Sampling

30-day Avg. 7-day Avg. Daily Max Frequency1 Type2

50796 Acrylamide (μg/l) 0.064 Monthly Composite

WET, Chronic6

TKP6C

Static Renewal 7 Day Chronic Pimephales promelas

NOEC or

IC25 ≥ IWC7

Quarterly

3 Composites/ Test

TKP3B

Static Renewal 7 Day Chronic Ceriodaphnia Dubia

NOEC or

IC25 ≥ IWC7 Quarterly 3 Composites/

Test

1 Monitoring frequency reductions may be granted, in accordance with the Baseline Monitoring Frequency, Sample Type, and Reduced Monitoring Frequency Policy for Industrial and Domestic Wastewater Treatment Facilities (WQP-20)

2 See the definition of “composite” in Part I.D of this permit. If the division determines that a flow-weighted composite sample is impracticable for a facility, a time composite sample of four equal aliquots collected at two-hour intervals will be allowed. The monitoring frequency and sample type will be specified in the certification. See Section VI.A of the fact sheet for more information.

3 The 30-day average effluent limitation for flow is identified in the certification, is generally based on the design capacity of the facility as outlined in the most recent site approval, and is enforceable under this permit. Facilities with flow equalization basin and reclaimed water configurations may be addressed differently. See 61.8(2)(f).

4 The monitoring frequency and sample type for effluent flow is specified in the certification and is fully enforceable under this permit. Mechanical type treatment facilities are typically required to have both influent and effluent flow measuring and recording devices. This requirement may be waived in cases where the division determines that either influent or effluent flow measurements are impractical. For these facilities, flow measuring and sampling type will be specified in the certification. If only one device is applicable, then that device will be used to report both influent and effluent flow.

However, where these devices are not in place at the time of certification, the permittee has one year from the end of the calendar month that certification was given to install the required equipment. Where such equipment is in place, the frequency and type of flow monitoring will be "Continuous" and "Recorder", respectively. Where such equipment is not in place, the frequency and type of flow monitoring, during the interim period, will be specified in the certification. For certain facilities, the use of a metered pumping rate or potable water use or may be allowed. In these cases, the monitoring frequency and sample type are determined and specified in the certification.

5 For E. coli the statistic used is the Geometric Mean, which is based on Method 1: Geometric Mean = (a*b*c*d*...)(1/n), or Method 2: Geometric Mean = antilog([log(a)+log(b)+log(c)+log(d)+...]/n).

6 Monitoring frequency for WET testing are implemented in accordance with the Division’s Whole Effluent Toxicity (WET)

Testing Policy. For chronic WET, “Composite” = 24 hour Composite. The in-stream waste concentration (IWC) for each facility is specified in the certification and determined using the following equation: IWC = [Facility Flow (FF)/(Stream

Chronic Low Flow (annual) + FF)] X 100%

7 IWC = 34%, see Fact Sheet for more information.

Permitted Feature ID: 001A Permitted Feature Type: External Outfall Limit Set: Z

PFAS Monitoring Requirements

ICIS

Code

Effluent Parameter Monitoring Requirements

Frequency Sample Type

51521 Perfluorooctanoic Acid [PFOA], ng/l 1/Permit Term Grab

51522 Perfluorobutanoic Acid [PFBA], ng/l 1/Permit Term Grab

51525 Perfluorooctanesulfonamide [PFOSA (or FOSA)], ng/l 1/Permit Term Grab

51623 Perfluoropentanoic acid [PFPeA], ng/l 1/Permit Term Grab

51624 Perfluorohexanoic acid [PFHxA], ng/l 1/Permit Term Grab

51625 Perfluoroheptanoic acid [PFHpA], ng/l 1/Permit Term Grab

51626 Perfluorononanoic acid [PFNA], ng/l 1/Permit Term Grab

51627 Perfluorodecanoic acid [PFDA], ng/l 1/Permit Term Grab

51628 Perfluoroundecanoic acid [PFUnA (or PFUdA)], ng/l 1/Permit Term Grab

51629 Perfluorododecanoic acid [PFDoA], ng/l 1/Permit Term Grab

51630 Perfluorotridecanoic acid [PFTrDA (or RFTriA)], ng/l 1/Permit Term Grab

51631 Perfluorotetradecanoic acid [PFTeDA (or PFTA or PFTeA)], ng/l 1/Permit Term Grab

51643 2-[N-ethylperfluorooctanesulfonamido] acetic acid [NEtFOSAA], ng/l 1/Permit Term Grab

51644 2-[N-methylperfluorooctanesulfonamido] acetic acid [NMeFOSAA], ng/l 1/Permit Term Grab

52602 Perfluorobutanesulfonic acid [PFBS], ng/l 1/Permit Term Grab

52603 Perfluorodecanesulfonic acid [PFDS], ng/l 1/Permit Term Grab

52604 Perfluoroheptanesulfonic acid [PFHpS], ng/l 1/Permit Term Grab

52605 Perfluorohexanesulfonic acid [PFHxS], ng/l 1/Permit Term Grab

52606 Perfluorooctanesulfonic acid [PFOS], ng/l 1/Permit Term Grab

52607 4:2 Fluorotelomer sulfonic acid [4:2 FTS], ng/l 1/Permit Term Grab

52608 6:2 Fluorotelomer sulfonic acid [6:2 FTS], ng/l 1/Permit Term Grab

52609 8:2 Fluorotelomer sulfonic acid [8:2 FTS], ng/l 1/Permit Term Grab

52610 Perfluoropentane sulfonic acid [PFPeS], ng/l 1/Permit Term Grab

52611 Perfluorononane sulfonic acid [PFNS], ng/l 1/Permit Term Grab

52612 Hexafluoropropylene oxide dimer acid [Gen-X (or HFPO-DA or HPFA-DA], ng/l 1/Permit Term Grab

52632 Perfluorododecanesulfonic acid [PFDoS], ng/L 1/Permit Term Grab

52641 N-methyl perfluorooctanesulfonamide [NMeFOSA], ng/L 1/Permit Term Grab

52642 N-ethyl perfluorooctanesulfonamide [NEtFOSA], ng/L 1/Permit Term Grab

51642 N-methyl perfluorooctanesulfonamidoethanol [NMeFOSE], ng/L 1/Permit Term Grab

51641 N-ethyl perfluorooctanesulfonamidoethanol [NEtFOSE], ng/L 1/Permit Term Grab

52636 4,8-Dioxa-3H-perfluorononanoic acid [ADONA], ng/L 1/Permit Term Grab

52629 Perfluoro(2-ethoxyethane)sulfonic acid [PFEESA], ng/L 1/Permit Term Grab

52624 Perfluoro-3-methoxypropanoic acid [PFMPA], ng/L 1/Permit Term Grab

52638 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid [9CL-PF3ONS], ng/L 1/Permit Term Grab

52639 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid [11CL-PF3OUDS], ng/L 1/Permit Term Grab

PF006 Perfluoro-4-methoxybutanoic acid [PFMBA], ng/L 1/Permit Term Grab

52626 Nonafluoro-3,6-dioxaheptanoic acid [NFDHA], ng/L 1/Permit Term Grab

PF001 3-Perfluoropropyl propanoic acid [3:3 FTCA], ng/L 1/Permit Term Grab

PF007 2H,2H,3H,3H-Perfluorooctanoic acid [5:3 FTCA], ng/L 1/Permit Term Grab

PF005 3-Perfluoroheptyl propanoic acid [7:3 FTCA], ng/L 1/Permit Term Grab

87006 PFAS Sum, ng/l* 1/Permit Term Calculated 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.

Permitted Feature ID: USTA1 Permitted Feature Type: Receiving Water (ambient)

Ambient Temperature Monitoring

ICIS

Code

Effluent Parameter

Effluent Limitations Maximum Concentrations

Monitoring Requirements

MWAT Daily Maximum Frequency Sample Type

00010 Temp DM (°C) April-October Report Continuous Recorder

00010 Temp DM (°C) November-March Report Continuous Recorder

00010 Temp MWAT (°C) April-October Report Continuous Recorder

00010 Temp MWAT (°C) November-March Report Continuous Recorder

1. Compliance Schedule

a. Activities to Meet Total Recoverable Arsenic Final Limits – In order to meet Total Recoverable Arsenic limitations, the following schedule are included in the permit.

Code Event Description Due Date

43699 Facility Evaluation Plan Submit a report that identifies sources of arsenic to the wastewater treatment facility and identifies strategies to control these sources or treatment alternatives such that compliance with the final limitations may be attained.

12/31/2025

00899 Implementation Schedule Submit a progress report summarizing the progress in implementing the strategies to control sources such that compliance with the final limitations may be attained.

12/31/2026

CS017 Achieve Final Compliance with Emissions or Discharge Limits

Submit study results that show compliance has been attained with the final limitations.

12/31/2027

2. Special Studies

a. Mixing Zone Analyses – Conduct remaining threshold tests for exclusion from further analysis under

Mixing Zone Regulations. The second threshold test is the Application of the Mixing Zone Exclusion Tables (p. 20, Colorado Mixing Zone Implementation Guidance, February 2002). Under this compliance action, the permittee will collect the necessary site-specific data, perform the required analysis, and provide a report to the Division. The report will indicate the findings of this threshold test and, if not excluded, provide the workplan for the next threshold test (i.e., determining of the size of the physical and regulatory mixing zones).

50008 Submit Study Results

During stream flow conditions that are at or below the 15th percentile of streamflow, collect site-specific data, perform threshold tests based on Mixing Zone Exclusion Tables, and submit study results.

11/30/2026

b. Hydrocarbon Analysis – The permittee shall submit a report annually, documenting the analytical results from the Purgeables by GC/MS and Base/Neutrals and Acids (including PAHs) by GC/MS analyses.

50008 Submit Study Results

Submit analytical results from the Purgeables by GC/MS and Base/Neutrals and Acids (including PAHs) by GC/MS annual analyses.

Annual, beginning May 31, 2023

Certification issued 11/10/2022 Effective December 1, 2022 Certification Expires: May 31, 2027

This certification under the permit requires that specific actions be performed at designated times. The certification holder is legally obligated to comply with all terms and conditions of the permit.

This certification was approved by:

Michelle DeLaria, Unit Manager

Permits Section

Water Quality Control Division

Water Quality Control Division