9-Attachment A Discharge Permit.pdf

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT

Water Quality Control Division

AUTHORIZATION TO DISCHARGE UNDER THE

COLORADO DISCHARGE PERMIT SYSTEM

PERMIT NUMBER CO0047651

In compliance with the provisions of the Colorado Water Quality Control Act, (25-8-101 et seq., CRS, 1973 as amended), for both discharges to surface and ground waters, and the Federal Water Pollution Control Act, as amended (33 U.S.C. 1251 et seq.; the "Act"), for discharges to surface waters only, the

Boulder County is authorized to discharge from the Eldorado Springs wastewater treatment plant located in the South 1/4, West 1/4, Section 30, Township 1 South, Range 70 West; Eldorado Springs, CO 80025; at 39.934440° N, 105.273333° W.

to South Boulder Creek in accordance with effluent limitations, monitoring requirements and other conditions set forth in Parts I and II hereof.

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

The applicant may demand an adjudicatory hearing within thirty (30) calendar days of the date of issuance of the final permit determination, per the Colorado State Discharge Permit System Regulation 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 1973 and the Colorado State 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 and the authorization to discharge shall expire at midnight, March 31st , 2022

Issued and Signed this 1st day of March, 2017

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT

Erin Scott, Acting Permits Section Manager

ISSUED: March 1, 2017

EFFECTIVE: April 1, 2017

PART I

Permit No.: CO0047651

TABLE OF CONTENTS

PART I

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

1. Permitted Feature(s)

2. Limitations, Monitoring Frequencies and Sample Types for Effluent Parameters

3. Monitoring Frequency and Sample Type Influent Parameters

4. Special Studies and Additional Monitoring

B. TERMS AND CONDITIONS

1. Service Area

2. Design Capacity

3. Expansion Requirements

4. Facilities Operation and Maintenance

5. Compliance Schedule(s)

6. Pretreatment Program - Industrial Waste Management

C. DEFINITION OF TERMS

D. General Monitoring, SAmpling and reporting requirements

1. Routine Reporting of Data

2. Annual Biosolids Report

3. Representative Sampling

4. Influent and Effluent Sampling Points

5. Analytical and Sampling Methods for Monitoring and Reporting

6. Records

7. Flow Measuring Devices

8. Signatory Requirements

PART II

A. NOTIFICATION REQUIREMENTS

1. Notification to Parties

2. Change in Discharge

3. Noncompliance Notification

5. Transfer of Ownership or Control

6. Other Notification Requirements

7. Bypass Notification

8. Bypass

9. Upsets

10. Submission of Incorrect or Incomplete Information

B. RESPONSIBILITIES

1. Reduction, Loss, or Failure of Treatment Facility

2. Inspections and Right to Entry

3. Duty to Provide Information

4. Availability of Reports

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

6. Oil and Hazardous Substance Liability

7. State Laws

8. Permit Violations

9. Severability

10. Confidentiality

11. Fees

12. Duration of Permit

13. Section 307 Toxics

14. Effect of Permit Issuance

PART III

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

1. Permitted Feature(s)

Beginning no later than the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from, and self-monitoring samples taken in accordance with the monitoring requirements shall be obtained from permitted feature(s):

001A following disinfection and prior to mixing with the receiving stream. 39.934440° N, 105.273333° W

The location(s) provided above will serve as the point(s) of compliance for this permit and are appropriate as they are located after all treatment and prior to discharge to the receiving water. Any discharge to the waters of the State from a point source other than specifically authorized by this permit is prohibited.

In accordance with the Water Quality Control Commission Regulations for Effluent Limitations, Section 62.4, and the Colorado Discharge Permit System Regulations, Section 61.8(2), 5 C.C.R. 1002-61, the permitted discharge shall not contain effluent parameter concentrations which exceed the limitations specified below or exceed the specified flow limitation.

2. Limitations, Monitoring Frequencies and Sample Types for Effluent Parameters

In order to obtain an indication of the probable compliance or noncompliance with the effluent limitations specified in Part I.A, the permittee shall monitor all effluent parameters at the frequencies and sample types specified below. Such monitoring will begin immediately and last for the life of the permit unless otherwise noted. The results of such monitoring shall be reported on the Discharge Monitoring Report form (See Part I.D.).

Self-monitoring sampling by the permittee for compliance with the effluent monitoring requirements specified in this permit, shall be performed at the location(s) noted in Part I.A.1 above. If the permittee, using an approved analytical method, monitors any parameter more frequently than required by this permit, then the results of such monitoring shall be included in the calculation and reporting of the values required in the Discharge Monitoring Report Form (DMRs) or other forms as required by the Division. Such increased frequency shall also be indicated.

Percentage Removal Requirements (BOD5 and TSS Limitations) - As noted in the limits table(s), the arithmetic mean of the BOD5 and TSS concentrations for effluent samples collected during the DMR reporting period shall demonstrate a minimum of eighty-five percent (85%) removal of both BOD5 and TSS, as measured by dividing the respective difference between the mean influent and effluent concentrations for the DMR monitoring period by the respective mean influent concentration for the DMR monitoring period, and multiplying the quotient by 100.

Oil and Grease Monitoring: For every outfall with oil and grease monitoring, in the event an oil sheen or floating oil is observed, a grab sample shall be collected and analyzed for oil and grease, and reported on the appropriate DMR under parameter 03582. In addition, corrective action shall be taken immediately to mitigate the discharge of oil and grease. A description of the corrective action taken should be included with the DMR.

Total Residual Chlorine: Monitoring for TRC is required only when chlorine is in use.

Flow Recording Device: For this facility, a single flow recording device is provided and is located at the point inflow to the treatment plant. Since effluent flows will not be significantly different from influent flows, the single flow measurement device will be used for the recording and reporting of both influent and effluent flows. Reported influent flows will be used to monitor compliance with the effluent flow limitation and hydraulic loading to the plant.

Metals: Metals concentrations measured in compliance with the effluent monitoring requirements listed in Part I.A of this permit may be used to satisfy any pretreatment or industrial waste management metals monitoring requirements listed in Part I.B.6, if the metals are in the same form (i.e. total). Sampling must be conducted in accordance with Part I.B.6.

Permitted Feature/Limit Set 001A

ICIS

Code Effluent Parameter

Effluent Limitations Maximum Concentrations Monitoring Requirements

30-Day

Average

7-Day

Average

Daily

Maximum

2-Year

Average Frequency Sample Type

50050 Effluent Flow (MGD) 0.032

Report Continuous Recorder

00010

Temp Daily Max (°C)

November through April, Beginning 11/01/2017

Report Report

Continuous Recorder

00010 Temp MWAT (°C) Nov-April, Beginning 11/1/2017 Report

Continuous Recorder

00400 pH (su) 6.5-9 Weekly Grab

51040 E. coli (#/100 ml) 876 1752

127 Monthly Grab

50060 TRC (mg/l) 0.077

0.019 0.012 Quarterly Grab

00640 Total Inorganic Nitrogen as N

(mg/l) Until 12/31/18

Report Report Monthly Composite

(mg/l) Beginning 1/01/19

10 Report Monthly Composite

(mg/l) Beginning 1/01/22

10 1.5 Monthly Composite

00610 Total Ammonia as N (mg/l)

Monthly Composite

January 26

26 3.9 Monthly Composite

February 26

26 4.5 Monthly Composite

March 24

24 4.9 Monthly Composite

April 33

48 4.9 Monthly Composite

May 65

65 7.8 Monthly Composite

June 65

65 40 Monthly Composite

July 65

65 65 Monthly Composite

August 65

65 24 Monthly Composite

September 65

65 20 Monthly Composite

October 35

65 5.2 Monthly Composite

November 21

21 3.3 Monthly Composite

December 26 26 4.0 Monthly Composite

00310 BOD5, effluent (mg/l) 30 45

Quarterly Composite

81010 BOD5 (% removal) 85 (min)

Quarterly Calculated

00530 TSS, effluent (mg/l) 30 45

Quarterly Composite

81011 TSS (% removal) 85 (min)

Quarterly Calculated

84066 Oil and Grease (visual)

Report Weekly Visual

03582 Oil and Grease (mg/l) 10 Contingent Grab

00978 As, TR (µg/l) Report

Report 2 Days/Year Composite

01306 Cu, PD (µg/l) Report Report Report 2 Days/Year Composite

3. Monitoring Frequency and Sample Type Influent Parameters

Regardless of whether or not an effluent discharge occurs and in order to obtain an indication of the current influent loading as compared to the approved capacity specified in Part I.A.3 and Part I.B.2; the permittee shall monitor influent parameters at the following required frequencies, the results to be reported on the Discharge Monitoring Report (See Part I.D):

If the permittee monitors any parameter more frequently than required by the permit, using an approved test procedure or as specified in the permit, the result of this monitoring shall be included in the calculation and reporting of data to the Division.

Self-monitoring samples taken in compliance with the monitoring requirements specified below shall be taken at the following location(s): Outfall 300I, at a representative point prior to biological treatment..

Permitted Feature 300I

ICIS

Code

Parameter

Discharge Limitations Maximum Concentrations Monitoring

Frequency Sample Type 30-Day

Average 7-Day

Average Daily Max.

50050 G Flow, mgd Report Report Continuous Recorder

00180 G Plant Capacity (% of Capacity - Hydraulic) 1

Report Monthly Calculated 1

00310 G BOD5, mg/l Report Report Monthly Composite

00310 G BOD5, lbs/day Report Report Monthly Calculated

00180 G Plant Capacity (% of Capacity - Organic) 1

Report Monthly Calculated 1

00530G Total Suspended Solids, mg/l

Report Report Monthly Composite

1 The % capacity is to be reported against the listed capacities of 0.032 MGD for the hydraulic capacity and 73 lbs BOD5/day for the organic capacities as noted in Site Approval 4911. The percentage should be calculated using the 30-day average values divided by the corresponding capacity, times 100.

4. Special Studies and Additional Monitoring

a. Temperature Monitoring Equipment- The facility is required to install continuous temperature monitoring equipment by to comply with the temperature monitoring ‘continuous’ requirements listed Part I.A. 2.

Code Event Description Due Date

04301 Install Temperature Meters

The permittee is to submit a document certifying that continuous temperature monitoring equipment has been installed and is operational.

November 1, 2017

c. 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

Collect site-specific data, perform threshold tests based on Mixing Zone Exclusion Tables, and submit study results.

03/01/19

50008 Submit Study Results

If a low flow condition is not reached on the receiving water during the first three years, the permittee shall collect the site-specific data, perform threshold tests based on Mixing Zone Exclusion Tables, and submit study results.

12/31/21

B. TERMS AND CONDITIONS

1. Service Area

All wastewater flows contributed in the service area may be accepted by the Eldorado Springs Wastewater Treatment Facility for treatment at the permittee's wastewater treatment plant provided that such acceptance does not cause or contribute to an exceedance of the throughput or design capacity of the treatment works or the effluent limitations in Part I.A, or constitute a substantial impact to the functioning of the treatment works, degrade the quality of the receiving waters, or harm human health, or the environment.

In addition, the permittee shall enter into and maintain service agreements with any municipalities that discharge into the wastewater treatment facility. The service agreements shall contain all provisions necessary to protect the financial, physical, and operational integrity of the wastewater treatment works.

2. Design Capacity

Based on Site Approval 4911, the design capacity of this domestic wastewater treatment works is 0.032 million gallons per day (MGD) for hydraulic flow (30-day average) and 73 lbs. BOD5 per day for organic loading (30-day average).

3. Expansion Requirements

Pursuant to Colorado Law, C.R.S. 25-8-501 (5 d & e), the permittee is required to initiate engineering and financial planning for expansion of the domestic wastewater treatment works whenever throughput reaches eighty (80) percent of the treatment capacity. Such planning may be deemed unnecessary upon a showing that the area served by the domestic wastewater treatment works has a stable or declining population; but this provision shall not be construed as preventing periodic review by the Division should it be felt that growth is occurring or will occur in the area.

The permittee shall commence construction of such domestic wastewater treatment works expansion whenever throughput reaches ninety-five (95) percent of the treatment capacity or, in the case of a municipality, either commence construction or cease issuance of building permits within such municipality until such construction is commenced; except that building permits may continue to be issued for any construction which would not have the effect of increasing the input of wastewater to the sewage treatment works of the municipality involved.

Where unusual circumstances result in throughput exceeding 80% of treatment capacity, the permittee may, in lieu of initiating planning for expansion, submit a report to the Division that demonstrates that it is unlikely that the event will reoccur, or even if it were to reoccur, that 95% of the treatment capacity would not be exceeded.

Where unusual circumstances result in throughput exceeding 95% of the treatment capacity, the permittee may, in lieu of initiating construction of the expansion, submit a report to the Division that demonstrates that the domestic wastewater treatment works was in compliance at all times during the events and that it is extremely unlikely that the event will reoccur.

Where the permittee submits a report pursuant to unusual circumstances, and the Division, upon review of such report, determines in writing to the permittee that the report does not support the required findings, the permittee shall initiate planning and/or construction of the domestic wastewater treatment works as appropriate.

4. Facilities Operation and Maintenance

The permittee shall at all times properly operate and maintain all facilities and systems of treatment and control including all portions of the collection system and lift stations owned by the permittee (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 effective performance, and adequate laboratory and process controls, including 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 regulations. 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.

5. Compliance Schedule(s)

a. Activities to Meet TIN daily maximum limit – In order to meet TIN daily maximum limit, the following schedule are included in the permit.

CS011 Plan, Report, or Scope of Work

Submit a report describing the actions that will be taken to attain compliance with the limitations.

12/31/17

CS016 Complete Required Work

Complete all appropriate actions, which will allow the permittee to meet the limitations.

12/31/18

b. Activities to Meet TIN 2 year rolling average limitation – In order to meet TIN 2 year rolling average limitation, the following schedule are included in the permit.

CS011 Plan, Report, or Scope of Work

Submit a report describing the actions that will be taken to attain compliance with the limitation.

12/31/17

CS010 Status/Progress Report

Submit progress report summarizing the progress in actions taken to attain compliance with the limitation.

12/31/18

CS010 Status/Progress Report

Submit progress report summarizing the progress in actions taken to attain compliance with the limitation.

12/31/19

CS010 Status/Progress Report

Submit progress report summarizing the progress in actions taken to attain compliance with the limitation.

12/31/20

CS016 Complete Required Work

Complete all appropriate actions, which will allow the permittee to meet the limitation.

12/31/21

Regulation 61.8(3)(n)(i) states that a report should be submitted to the Division no later than 14 calendar days following each date identified in the schedule of compliance. The 14 days have already been incorporated into the above dates and therefore all reports are due on or before the date listed in the table.

6. Pretreatment Program - Industrial Waste Management

a. The Permittee has the responsibility to protect the Domestic Wastewater Treatment Works (DWTW), as defined at section 25.8.103(5) of the Colorado Water Quality Control Act, or the Publicly-Owned Treatment Works (POTW), as defined at 40 CFR section 403.3(q) of the federal pretreatment regulations, from pollutants which would cause pass through or interference, as defined at 40 CFR 403.3(p) and (k), or otherwise be incompatible with operation of the treatment works including interference with the use or disposal of municipal sludge.

b. Pretreatment Standards (40 CFR Section 403.5) developed pursuant to Section 307 of the Federal Clean

Water Act (the Act) require that the Permittee shall not allow, under any circumstances, the introduction of the following pollutants to the DWTW from any source of non-domestic discharge:

i. Pollutants which create a fire or explosion hazard in the DWTW, including, but not limited to, wastestreams with a closed cup flashpoint of less than sixty (60) degrees Centigrade (140 degrees Fahrenheit) using the test methods specified in 40 CFR Section 261.21;

ii. Pollutants which will cause corrosive structural damage to the DWTW, but in no case discharges with a pH of lower than 5.0 s.u., unless the treatment facilities are specifically designed to accommodate such discharges;

iii. Solid or viscous pollutants in amounts which will cause obstruction to the flow in the DWTW, or otherwise interfere with the operation of the DWTW;

iv. Any pollutant, including oxygen demanding pollutants (e.g., BOD), released in a discharge at a flow rate and/or pollutant concentration which will cause Interference with any treatment process at the

DWTW;

v. Heat in amounts which will inhibit biological activity in the DWTW resulting in Interference, but in no case heat in such quantities that the temperature at the DWTW treatment plant exceeds forty (40) degrees Centigrade (104 degrees Fahrenheit) unless the Approval Authority, upon request of the DWTW, approves alternate temperature limits;

vi. Petroleum oil, non-biodegradable cutting oil, or products of mineral oil origin in amounts that will cause Interference or Pass Through;

vii. Pollutants which result in the presence of toxic gases, vapors, or fumes within the DWTW in a quantity that may cause acute worker health and safety problems;

viii. Any trucked or hauled pollutants, except at discharge points designated by the DWTW; and

ix. Any specific pollutant that exceeds a local limitation established by the Permittee in accordance with the requirements of 40 CFR Section 403.5(c) and (d).

x. Any other pollutant which may cause Pass Through or Interference.

c. EPA shall be the Approval Authority and the mailing address for all reporting and notifications to the Approval Authority shall be: USEPA 1595 Wynkoop St. 8ENF-W-NP, Denver, CO 80202-1129. Should the State be delegated authority to implement and enforce the Pretreatment Program in the future, the Permittee shall be notified of the delegation and the state permitting authority shall become the Approval Authority.

d. In addition to the general limitations expressed above, more specific Pretreatment Standards have been and will be promulgated for specific industrial categories under Section 307 of the Act (40 CFR Part 405 et.

seq.).

e. The Permittee must notify the state permitting authority and the Approval Authority, of any new introductions by new or existing industrial users or any substantial change in pollutants from any industrial user within sixty (60) calendar days following the introduction or change. Such notice must identify:

i. Any new introduction of pollutants into the DWTW from an industrial user which would be subject to

Sections 301, 306, or 307 of the Act if it were directly discharging those pollutants; or

ii. Any substantial change in the volume or character of pollutants being introduced into the DWTW by any industrial user;

iii. For the purposes of this section, adequate notice shall include information on:

(A) The identity of the industrial user;

(B) The nature and concentration of pollutants in the discharge and the average and maximum flow of the discharge to be introduced into the DWTW; and

(C) Any anticipated impact of the change on the quantity or quality of effluent to be discharged from or biosolids or sludge produced at such DWTW.

iv. For the purposes of this section, a significant industrial user shall include:

(A) Any discharger subject to Categorical Pretreatment Standards under Section 307 of the Act and 40 CFR chapter I and subchapter N;

(B) Any discharger which has a process wastewater flow of 25,000 gallons or more per day;

(C) Any discharger contributing five percent or more of the average dry weather hydraulic or organic capacity of the DWTW treatment plant;

(D) Any discharger who is designated by the Approval Authority as having a reasonable potential for adversely affecting the DWTWs operation or for violating any Pretreatment Standard or requirements;

f. At such time as a specific Pretreatment Standard or requirement becomes applicable to an industrial user of the Permittee, the state permitting authority and/or Approval Authority may, as appropriate:

i. Amend the Permittee's NPDES discharge permit to require the Permittee to develop and submit an approvable Pretreatment program under a compliance schedule, in accordance with procedures in 40 CFR 403.8(e). The modification of a POTW's NPDES Permit for the purposes of incorporating a POTW Pretreatment Program approved in accordance with the procedure in §403.11 shall be deemed a minor Permit modification subject to the procedures in 40 CFR 122.63(g); or,;

ii. Require the Permittee to specify, by ordinance, order, or other enforceable means, the type of pollutant(s) and the maximum amount which may be discharged to the Permittee's DWTW for treatment. Such requirement shall be imposed in a manner consistent with the program development requirements of the General Pretreatment Regulations at 40 CFR Part 403; and/or,

iii. Require the Permittee to monitor its discharge for any pollutant which may likely be discharged from the Permittee's DWTW, should the industrial user fail to properly pretreat its waste.

The state permitting authority and the Approval Authority retains, at all times, the right to take legal action against any source of nondomestic discharge, whether directly or indirectly controlled by the Permittee, for violations of a permit, order or similar enforceable mechanism issued by the Permittee, violations of any Pretreatment Standard or requirement, or for failure to discharge at an acceptable level under national standards issued by EPA under 40 CFR, chapter I, subchapter N. In those cases where a CDPS permit violation has occurred because of the failure of the Permittee to properly develop and enforce Pretreatment Standards and requirements as necessary to protect the DWTW, the state permitting authority and/or Approval Authority shall hold the Permittee and/or industrial user responsible and may take legal action against the Permittee as well as the Industrial user(s) contributing to the permit violation.

C. DEFINITION OF TERMS

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

2. “Applicable water quality criterion (AWQC)” is the quantitation target level or goal. The AWQC may be one of the following:

Where an effluent limit has been established,

i. The AWQC is the effluent limit.

Where an effluent limit has not been established, the AWQC may be

i. An applicable technology based effluent limit (TBEL);

ii. Half of a water quality standard;

iii. Half of a water quality standard as assessed in the receiving water, or potential WQBEL; or

iv. Half of a potential antidegradation based effluent limitation, which can be an antidegradation based average concentration or a potential non-impact limit.

3. "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).

4. "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.

5. "Daily Maximum limitation" for all parameters (except temperature, pH, dissolved oxygen, and WET) means the limitation for this parameter shall be applied as an average of all samples collected in one calendar day. For these parameters the DMR shall include the highest of the daily averages. For pH and dissolved oxygen, this means an instantaneous maximum (and/or instantaneous minimum) value. For WET, this means an instantaneous minimum value. The instantaneous value is defined as the analytical result of any individual sample. For pH and dissolved oxygen, DMRs shall include the maximum (and/or minimum) of all instantaneous values within the calendar month. For WET, DMRs shall include the minimum of all instantaneous values within the reporting period. For pH and dissolved oxygen, the value beyond the noted daily maximum limitation for the indicated parameter shall be considered a violation of this permit. For temperature, see Daily Maximum Temperature. For WET violation and failure descriptions, see Part I.B.5.

6. “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 minutes in the 2-hour maximum. Data from 11 pm to 12:59 am, would fall in the previous month. Data collected from 11:01 pm to 1:00 am would fall in the new month.

7. "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.

8. “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 letter noting that a result of TNTC was obtained, and list all individual analytical results and corresponding sampling dates for that month.

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

10. “IC25” or “Inhibition Concentration” is a point estimate of the toxicant concentration that would cause a given percent reduction in a non-lethal biological measurement (e.g. growth or reproduction) calculated from a continuous model (i.e. interpolation method). IC25 is a point estimate of the toxic concentration that would cause a 25-percent reduction in a non-lethal biological measurement.

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. “LC50” or “Lethal Concentration” is the toxic or effluent concentration that would cause death in 50 percent of the test organisms over a specified period of time.

14. “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 July-September).

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.

1st MWAT Calculation as average of previous 7 days Day 8: Average of all temperature data collected during the calendar day.

2nd MWAT Calculation as average of previous 7 days Day 9: Average of all temperature data collected during the calendar day.

3rd MWAT Calculation as average of previous 7 days

15. “Minimum level (ML)” means the lowest concentration of an analyte that can be accurately and precisely quantified using a given method, as determined by the laboratory.

16. “NOEC” or “No-Observed-Effect-Concentration” is the highest concentration of toxicant to which organisms are exposed in a full life cycle or partial life cycle (short term) test, that causes no observable adverse effects on the test organisms (i.e. the highest concentration of toxicant in which the values for the observed responses are not statistically different from the controls). This value is used, along with other factors, to determine toxicity limits in permits.

17. "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.

18. “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.

19. "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.

20. "Recorder" requires the continuous operation of a chart and/or totalizer (or drinking water rotor meters or pump hour meters where previously approved.)

21. "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.5 for guidance on calculating averages and reporting analytical results that are less than the PQL).

22. “Sufficiently sensitive test procedures”:

i. An analytical method is ‘‘sufficiently sensitive’’ when the method detects and accurately and precisely quantifies the amount of the analyte. In other words there is a valid positive result; or

ii. An analytical method is “sufficiently sensitive” when the method accurately and precisely quantifies the result to the AWQC, as demonstrated by the ML is less than or equal to the AWQC. In other words, the level of precision is adequate to inform decision making; or

iii. An analytical method is “sufficiently sensitive” when the method achieves the required level of accuracy and precision, as demonstrated by the ML is less than or equal to the PQL. In other words, the most sensitive method is being used and properly followed.

23. "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, which represents a calendar month. 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.5 for guidance on calculating averages and reporting analytical results that are less than the PQL).

24. Toxicity Identification Evaluation (TIE) is a set of site-specific procedures used to identify the specific chemical(s) causing effluent toxicity.

25. “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).

26. "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.

27. “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.

28. 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 toxicity control options, and then confirm the reduction in effluent toxicity after the control measures are put in place.

29. "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.

30. "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.

31. “Two (2) -Year Rolling Average” (Antidegradation limits)- the average of all monthly average data collected in a two year period. Collection of the data required to calculate a two-year rolling average shall start immediately upon the effective date of the permit, but the data is not reported on a DMR until two years after the effective date of the permit. To calculate a two-year rolling average, add the current monthly average to the previous 23 monthly averages and divide the total by 24. This methodology continues on a rolling basis for the permit term (ie., in the first reporting period use data from month 1 to month 24, in the second reporting period use data from month 2 to month 25, then month 3 to month 26, etc).

Example: Two year rolling average = (MAC +MA1 +MA2 +...+MA23) ÷ 24 MAC = Current monthly average MA1 = First prior month’s monthly average MA2 = Second prior month’s monthly average MA23 = Twenty third prior month’s monthly average

Note, if there is not a discharge from the facility in a month during a two year period do not use zero (0) to represent the data for that month in the calculation, but do consider that month as part of the two year time span. The denominator in the two-year rolling average calculation will change to represent the actual number of months there was a discharge.

Example: Two year rolling average = (30 +45 +...+25) ÷ 22

Current monthly average= 30 mg/l First prior month’s monthly average= no discharge Second prior month’s monthly average= no discharge Third prior month’s monthly average=45 mg/l Twenty third prior month’s monthly average= 25 mg/l

For ammonia, two-year rolling averages may be set up for individual months, or may be grouped together for several months. When individual months have a specific limit, calculate the two-year rolling average as follows:

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

January 2010 DMR – Nothing to Report January 2011 DMR – Two-year rolling average = (MAC +MA1) ÷ 2

MAC = January 2011 monthly average MA1 = January 2010 monthly average

January 2012 DMR – Two-year rolling average = (MAC +MA1) ÷ 2 MAC = January 2012 monthly average MA1 = January 2011 monthly average

Where several months are grouped together and have the same limit, calculate the two-year rolling average as follows:

Example: Permit is effective January 2010 and there is a two-year rolling average limit specific to the months of January, February, and June.

January, February, June 2010 DMR- Nothing to Report 1st Reportable DMR – June 2011 DMR:

Two year rolling average = (MAC +MA1 +MA2 +MA3+MA4+MA5) ÷ 6

MAC = June 2011 monthly average MA1 = February 2011 monthly average MA2 = January 2011 monthly average MA3= June 2010 monthly average MA4 = February 2010 monthly average MA5 = January 2010 monthly average

2nd Reportable DMR – January 2012 DMR:

Two year rolling average = (MAC +MA1 +MA2 +MA3+MA4+MA5) ÷ 6

MAC = January 2012 monthly average MA1 = June 2011 monthly average MA2 = February 2011 monthly average MA3= January 2011 monthly average MA4 = June 2010 monthly average

MA5 = February 2010 monthly 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).

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

33. "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.

D. 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 and monitoring results shall be summarized for each calendar month. Reporting of all data gathered shall comply with the requirements of Part I.D. (General Requirements).

Prior to 21 December 2016, the permittee may elect to electronically submit DMRs instead of mailing paper DMRs by using the EPA’s Net-DMR service. Starting on 21 December 2016, the permittee must electronically report DMRs by using the EPA’s Net-DMR service unless a waiver is granted in compliance with 40 CFR 127.

If submitted on paper the data must be reported on Division approved discharge monitoring report (DMR) forms (EPA form 3320-1). The permittee must submit these forms by mail. 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

For both electronic and paper reporting the data must be 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 Discharge Monitoring Report paper and electronic 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. Annual Biosolids Report

The permittee shall provide the results of all biosolids monitoring and information on management practices, land application sites, site restrictions and certifications. Such information shall be provided no later than February 19th of each year. Reports shall be submitted addressing all such activities that occurred in the previous calendar year. If no biosolids were applied to the land during the reporting period, "no biosolids applied" shall be reported. Until further notice, biosolids monitoring results shall be reported on forms, or copies of forms, provided by the Division. Annual Biosolids Reports required herein, shall be signed and certified in accordance with the Signatory Requirements, Part I.D.1, and submitted as follows:

The original copy of each form shall be submitted to the following address:

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT,

WATER QUALITY CONTROL DIVISION

WQCD-PERMITS-B2

4300 CHERRY CREEK DRIVE SOUTH

DENVER, COLORADO 80246-1530

A copy of each form shall be submitted to the following address if any one of below conditions applies to this facility:

1. design flow rate is equal to or greater than one million gallons per day,

2. serves 10,000 people or more, or

3. is required to have an approved pretreatment program.

EPA BIOSOLIDS CENTER

EPA REGION 7

WWPD/WENF

11201 RENNER BOULEVARD

LENEXA, KANSAS 66219

ATTENTION: BIOSOLIDS PROGRAM MANAGER

3. Representative Sampling

Samples and measurements taken for the respective identified monitoring points as required herein shall be representative of the volume and nature of: 1) all influent wastes received at the facility, including septage, biosolids, etc.; 2) the monitored effluent discharged from the facility; and 3) biosolids produced at the facility.

All samples shall be taken at the monitoring points specified in this permit and, unless otherwise specified, before the influent, effluent, or biosolids wastestream joins or is diluted by any other wastestream, body of water, or substance.