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National Pollutant Discharge Elimination System (NPDES)/ State Disposal System (SDS) Permit Program Fact Sheet

Permit Reissuance MN0068195

Permittee: Minnesota River Valley Public Utilities Commission

PO Box 176 Le Sueur, Minnesota 56058-0176

Facility name: Minnesota River Valley Public Utilities Commission Wastewater Treatment Facility 1500 Commerce St

Le Sueur, Minnesota 56058-1118 Current permit expiration date: October 31, 2016 Public comment period begins: August 13, 2019 Public comment period ends: October 14, 2019 Receiving water: Minnesota River - Class 2B, 3C, 4A, 4B, 5, 6 water Permitting contact: Nancy Heskett 18 Wood Lake Drive Southeast

Rochester, MN 55904 507-206-2605 [email protected]

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 22

Table of Contents Page

Purpose and participation ................................................................................................................................................................ ................... 3 Applicable statutes ................................................................................................................................................................ .............................. 3 Purpose .................................................................................................................................................................................................................... 3 Public participation ............................................................................................................................................................................................ 3

Facility description ................................................................................................................................................................................................. 4 Facility and Outfall location ............................................................................................................................................................................ 4 Map of permitted facility .................................................................................................................................................................................. 5 Components and treatment technology .................................................................................................................................................... 5 Current information ........................................................................................................................................................................................... 5 Flow schematic ................................................................................................................................................................ ..................................... 6 Changes to facility or operation ..................................................................................................................................................................... 6 Significant industrial users (SIUs) ................................................................................................................................................................. 6 Recent compliance history ................................................................................................................................................................ ............... 6 Recent monitoring history ................................................................................................................................................................ ............... 6 Table 1: Recent monitoring history .............................................................................................................................................................. 7

Receiving water(s) .................................................................................................................................................................................................. 9 Use classification ................................................................................................................................................................ ................................. 9 Impairments ................................................................................................................................................................................................ .......... 9 Table 2: Impaired Waters and TMDL Status ............................................................................................................................................. 9

Existing permit effluent limits ......................................................................................................................................................................... 10 Technology based effluent limits (TBELs) ................................................................................................................................................ 10 Water quality based effluent limits (WQBELs) ....................................................................................................................................... 10 State Discharge Restrictions (SDRs) ........................................................................................................................................................... 11 Table 3: Current Limits and Monitoring Requirements ...................................................................................................................... 11

Proposed permit effluent limits ...................................................................................................................................................................... 12 Technology based effluent limits ................................................................................................................................................................. 12 Water quality based limits ............................................................................................................................................................................. 12

CBOD5 and DO ................................................................................................................................................................................................ 12 Mercury ............................................................................................................................................................................................................ 13 Phosphorus ...................................................................................................................................................................................................... 13

State Discharge Restrictions (SDRs) ........................................................................................................................................................... 13 Table 4: SD002 Proposed Limits and Monitoring Requirements ..................................................................................................... 13

Reasonable Potential for Chemical Specific Pollutants (40CFR§122.44(d)(1)).......................................................................... 15 Table 5. Analysis of reasonable potential for Cu and Ni ...................................................................................................................... 16 Table 6. Analysis of reasonable potential for the salty parameters ................................................................................................ 17 Whole Effluent Toxicity ................................................................................................................................................................................... 17 Phosphorus ................................................................................................................................................................................................ .......... 17

Figure 1: ................................................................................................................................................................ ........................................... 18 Figure 2: ................................................................................................................................................................ ........................................... 19

Additional requirements ................................................................................................................................................................ .................... 20 Compliance Schedule ........................................................................................................................................................................................ 20 Pollutant minimization plans ....................................................................................................................................................................... 20 Industrial Stormwater ..................................................................................................................................................................................... 20 Total facility requirements ................................................................................................................................................................ ............ 21

Antidegradation and anti-backsliding .......................................................................................................................................................... 21

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Purpose and participation

Applicable statutes

This fact sheet has been prepared according to the 40 CFR § 124.8 and 124.56 and Minn R. 7001.0100, subp. 3 in regards to a draft National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) permit to construct and/or operate wastewater treatment facilities and to discharge into waters of the state of Minnesota.

Purpose

This fact sheet outlines the principal issues related to the preparation of this draft permit and documents the decisions that were made in the determination of the effluent limitations and conditions of this permit.

Public participation

You may submit written comments on the terms of the draft permit or on the Commissioner’s preliminary determination. Your written comments must include the following:

1. A statement of your interest in the permit application or the draft permit.

2. A statement of the action you wish the Minnesota Pollution Control Agency (MPCA) to take, including specific references to sections of the draft permit that you believe should be changed.

3. The reasons supporting your position, stated with sufficient specificity as to allow the Commissioner to investigate the merits of your position.

You may also request that the MPCA Commissioner hold a public informational meeting. A public informational meeting is an informal meeting, which the MPCA may hold to help clarify and resolve issues.

In accordance with Minn. R. 7000.0650 and Minn. R. 7001.0110, your petition requesting a public informational meeting must identify the matter of concern and must include the following: items one through three identified above; a statement of the reasons the MPCA should hold the meeting; and the issues you would like the MPCA to address at the meeting.

In addition, you may submit a petition for a contested case hearing. A contested case hearing is a formal hearing before an administrative law judge. Your petition requesting a contested case hearing must include a statement of reasons or proposed findings supporting the MPCA decision to hold a contested case hearing pursuant to the criteria identified in Minn. R. 7000.1900, subp. 1 and a statement of the issues proposed to be addressed by a contested case hearing and the specific relief requested. To the extent known, your petition should include a proposed list of witnesses to be presented at the hearing, a proposed list of publications, references or studies to be introduced at the hearing, and an estimate of time required for you to present the matter at hearing.

You must submit all comments, requests, and petitions during the public comment period identified on page one of this notice. All written comments, requests, and petitions received during the public comment period will be considered in the final decisions regarding the permit. If the MPCA does not receive any written comments, requests, or petitions during the public comment period, the Commissioner or other MPCA staff as authorized by the Commissioner will make the final decision concerning the draft permit.

Comments, petitions, and/or requests must be submitted by the last day of the public comment period to:

Nancy Heskett Minnesota Pollution Control Agency 18 Wood Lake Drive Southeast Rochester, MN 55904

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 The permit will be reissued if the MPCA determines that the proposed Permittee or Permittees will, with respect to the facility or activity to be permitted, comply or undertake a schedule to achieve compliance with all applicable state and federal pollution control statutes and rules administered by the MPCA and the conditions of the permit and that all applicable requirements of Minn. Stat. ch. 116D and the rules promulgated thereunder have been fulfilled.

More detail on all requirements placed on the facility may be found in the permit document.

Facility description

The Minnesota River Valley Public Utilities Commission (MRVPUC) Wastewater Treatment Facility (facility) treats the combined municipal wastewater from the communities of Henderson and Le Sueur through a joint powers agreement, as well as pretreated wastewater from Agropur.

A lift station and force main system transports influent wastewater from the Henderson collection system to the Le Sueur collection system. The facility is constructed next to the existing pretreatment facility operated to pretreat wastewater from Agropur.

The facility has a continuous discharge (SD002) to the Minnesota River (Class 2B, 3C, 4A, 4B, 5, 6 water) and is designed to treat an average wet weather (AWW) flow of 1.842 million gallons per day (mgd), an average dry weather flow of 1.255 mgd and a peak hourly wet weather flow of 3.4 mgd. The facility is designed to treat approximately 2,000 pounds (lbs) of five-day carbonaceous biochemical oxygen demand (CBOD5) per day (annual average), and approximately 2,200 lbs of total suspended solids per day (annual average), prior to discharge into the Minnesota River. This is a Class A facility.

The facility is further described in plans and specifications on file with the MPCA by the firm of Bolton & Menk, Inc., Mankato, Minnesota.

Facility and Outfall location

This is an existing municipal facility that treats wastewater from the communities of Le Sueur and Henderson. The facility and outfall (SD002) are located in the NE ¼ of Section 25, Township 112 North, on the north side of Le Sueur, on the north end of North Commerce Street, respectively.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Map of permitted facility

Components and treatment technology

Current information

The facility consists of two lift stations with forcemains, screening and grit removal, three extended aeration-activated sludge units with biological phosphorus removal capabilities, centrifugal blowers, chemical phosphorus removal equipment, three clarifiers, an operations building with laboratory and control instrumentation, a chlorine disinfection tank with dechlorination and reaeration systems, an effluent outfall, and standby power equipment. The biosolids treatment system consists of interim storage of waste biosolids prior to dewatering, then heat pasteurization treatment, and final biosolids storage in a building, which provides 180 days of storage. Final disposal of biosolids is through land application on approved agricultural land.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Flow schematic

Changes to facility or operation

The facility completed decommissioning of the Le Sueur facility stabilization ponds in 2013 and that individual permit was terminated.

Significant industrial users

The Permittee receives process wastewater from one significant industrial users (SIUs), Agropur. The Permittee holds a contract with this SIU to limit and monitor pollutants of concern.

Recent compliance history

A Compliance Evaluation Inspection (CEI) was conducted on September 26, 2018, by Chandi McCracken-Holm of the MPCA. The CEI consisted of a visual inspection of the Facility and a discussion with Facility staff, Foster Transburg, Rich Kucera and consultant Todd Arlander. The Facility’s pretreatment and biosolids were not inspected. Based on the results of the CEI, several alleged violations of terms and conditions set forth in the NPDES/SDS Permit were documented which occurred in 2016, 2017 and 2018. These alleged violations were addressed in a letter of warning issued on May 3, 2019. The Facility has collected all required samples and met all applicable effluent limits since the inspection. For compliance and enforcement questions, please contact Cara Omana at 651-757-2891.

A separate inspection of the Facility’s Pretreatment program was conducted in September of 2018, by Jaramie Logelin of the MPCA and Foster Transburg of MRVPUC. It was noted that there is a categorical industrial user (CIU) in their service area that is not currently being regarded as a significant industrial user (SIU) and a discussion was held as to the requirements in their permit regarding this CIU along with a walk-through of the facility. No pretreatment violations were found.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Recent monitoring history

The following table shows the monthly reported values by the facility for February 2018 through February 2019. Where no number is given in the Limit column, the facility is required to monitor only for that parameter.

Table 1: Recent monitoring history 2018 2018 2018 2018 2018 2018 2018 2018 2018 2018 2018 2019 2019

Parameter Limit Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb

Bicarbonates mg/L 752 629 510 604 544 492 609 750 767 693 637

CBOD5 104 kg/d 6.1 7.1 16 8.5 9.4

CBOD5 174 kg/d 4.2 8.8 5.9 7.1 6.1 117 8 8.6

CBOD5 15 mg/L 1.5 1.7 3.4 2 2.3

CBOD5 25 mg/L 0.93 1.8 1 1.3 1.3 22 1.5 1.8

CBOD5 174 kg/d 7.4 11 26 12 10

CBOD5 279 kg/d 6.4 23 7.8 9.7 6 14 12

CBOD5 279 kg/d 454

CBOD5 25 mg/L 1.9 2.8 5.6 2.9 2.4

CBOD5 40 mg/L 1.5 4.9 1.2 1.7 1.3 2.6 2.2

CBOD5 40 mg/L 84

CBOD5 Percent Removal

85% 99 98 99 98 99 99 99 87 98 98 96 97

Calcium, Total mg/L 100 99 115 52 90 89 91 100 109 102 87

Chloride, Total mg/L 524 445 385 502 486 574 469 534 613 551 605

Chlorine, Total Residual

0.038 mg/L


0.038 mg/L 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05


0.038 mg/L

Fecal Coliform 200 #/100ml 2.7 7 38 48 57 89 25

Flow mgd 1.037 1.106 1.201 1.326 1.443 1.465 1.229 1.271 1.421 1.196 1.114 1.1 1.093

Flow mgd 1.207 1.292 1.474 1.748 1.757 1.817 1.487 1.702 1.561 1.391 1.367 1.193 1.383

Flow Mgal 29.023 34.28 36.02 41.11 43.3 45.41 38.1 38.12 44.05 35.88 34.52 34.11 30.61

Hardness mg/L 349 362 419 248 341 348 347 359 382 374 321

Magnesium, Total

mg/L 24 28 32 28 29 31 29 27 27 29 26

Mercury, Dissolved

ng/L 0.299

Mercury, Dissolved

ng/L 0.5

Mercury, Dissolved

ng/L 0.597

Mercury, Dissolved

ng/L 0.5

Mercury, Total 70 mg/d 2.452 2.756 5.081 1.831 2.7 1.9

Mercury, Total 70 mg/d 3.3 2.3 2.4 0.22

Mercury, Total 10 ng/L 0.63 1.7 0.371 0.529 0.961 0.368 0.59 0.52

Mercury, Total 10 ng/L 0.5 0.5 0.5 0.05

Mercury, Total 17 ng/L 1.3 3.4

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Mercury, Total 120 ng/L 4.903 2.778 5.5 3.661 5.3 3.7


Mercury, Total 17 ng/L 0.741 0.535 1.01 0.735 1.2 1


Nitrite Plus Nitrate, Total

mg/L 13 13 25 123

Ammonia, Total

mg/L 0.13 0.11 0.1 0.11 0.11 0.18 0.23 0.36 0.17 0.12 0.13

Ammonia, Total

mg/L 0.1 0.1

Nitrogen, Kjeldahl, Total

mg/L 1.6 2.1 2.1 1.6

Nitrogen, Total mg/L 1.6 15 27

Oxygen, Dissolved

mg/L 8.8 6.9 7.3 7.3 6.4 5.4 6.7 6.7

Oxygen, Dissolved

6 mg/L 8.5 7.9 6.7 7.4 7.5

pH 9 8.1 8.3 8.2 8.2 8.2 8.3 8.5 8.4 8.2 8.4 8.4 8.3 8.3

pH 6 7.4 7.7 7.6 7.8 7.6 7.4 7.4 7.5 7.4 7.8 7.7 7.5 7.6

Phosphorus, Total

1 mg/L 0.3 0.3 0.3 0.32 0.35 0.4 0.4 0.6 0.6 0.7 0.7 0.761 0.818

Phosphorus, Total

2,036 461 493 504.2 507 566 614 670.3 991 1,110 1,185 1,256 1,333 1,411

Phosphorus, Total

mg/L 0.3 0.44 0.26 0.37 0.64 0.56 0.68 2.5 0.92 0.76 0.82 0.89 0.97

Phosphorus, Total

kg/mo 58 105 96 98 364 154 103 107 114 113

Potassium, Total

mg/L 146 124 114 137 145 173 132 151 174 177 186

Sodium, Total mg/L 572 436 379 62 424 431 377 429 483 467 533

Solids, Total Dissolved

mg/L 1,600 1,680 1,770


mg/L 1,650 1,500 1,720 1,640 1,760 1,550 1,660 1,940 1,950 1,970

Solids, Total Suspended (TSS)

209 kg/d 39 37 27 30 35 45 35 29 47 41 58 70 74

TSS 30 mg/L 9.5 8.6 5.8 6.1 6.1 8 7.2 5.8 8.7 8.8 13 17 18

TSS 313 kg/d 39 53 30 32 48 51 50 42 73 46 70 80 81

TSS 45 mg/L 9.7 13 6 6.7 7.3 8.3 9.3 7.7 13 9 15 19 19

TSS Percent Removal

85 97 97 98 98 98 97 98 98 96 96 94 90

TSS, grab (Mercury)

mg/L 5.4 6

Specific Conductance

umhos/cm 2,980 2,650 2,370 2,920 2,650 3,080 2,300 2,830 3,070 3,200 3,390

Sulfate, Total mg/L 113 109 94 107 108 60 50 47 76 69 54

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Receiving water(s)

Use classification

This facility discharges to the Minnesota River. This reach is classified as a 2B, 3C, 4A, 4B, 5, 6 water. This classification indicates that the body of water is capable of sustaining aquatic life and recreation. More information on the classification of waters can be found in Minn. R. 7050.0140.

Impairments

Downstream impairments in the Minnesota River include Mercury in Fish Tissue/Mercury in Water Column, Dissolved Oxygen, Fecal Coliform, Turbidity and Polychlorinated Biphenyls (PCBF). The following table lists the Total Maximum Daily Load (TMDL) studies currently approved or underway to address these impairments.

Table 2: Impaired Waters and TMDL Status Downstream Impairments

Number of Impairments

TMDL Status

Minnesota River 31 Mercury in Fish Tissue 8 See the Wasteload Allocations (WLA) section below. Mercury in Water Column

5

Dissolved Oxygen 1 The Lower Minnesota River Low Dissolved Oxygen TMDL was approved by EPA on September 28th, 2004. Wastewater WLAs are implemented through the Minnesota River General Phosphorus permit. A WLA is assigned to this facility. See the WLA below.

Fecal Coliform 4 These impairments are located in the Lower Minnesota River Major Watershed. A TMDL has not yet been developed to address these impairments.

Turbidity 5 07020012-503 This impairment is addressed in the draft Minnesota River Turbidity TMDL. A WLA is assigned to this facility. See the WLA section below. These impairments are not addressed in the draft Minnesota River Turbidity TMDL as they are not located in the project area. TMDLs have not yet been completed to address the Turbidity impairments for AUIDs 07020012-501, -507, -506 and -505.

PCBF 8 See the Additional Information below. Mississippi River 22 Mercury in Fish Tissue 5 See the WLA section below. Mercury in Water Column

4

Total Suspended Solids 5 A draft South Metro Mississippi TSS TMDL has been completed. A WLA is assigned to this facility. See the WLA section below.

Fecal Coliform 1 The Upper Mississippi River – Bacteria TMDL was approved by EPA on November 20th, 2014. A WLA was not assigned to this facility in this TMDL.

PCBF 5 See the Additional Information below. PFOS-F 1 PFOS-W 1 Pepin Lake 1 Nutrient/Eutrophication Biological Indicators

1 The Lake Pepin – Excess Nutrients TMDL has not yet been completed. See the WLA section below. Note: Portions of the Minnesota River exceed river eutrophication standards (RES) but have not officially been listed as impaired as of today’s date. These reaches are the draft list of impaired waters.

Mississippi River 6 Mercury in Fish Tissue 3 See the WLA section below.

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PCBF 3 See the Additional Information below. Grand Total 60

Wasteload Allocations: Statewide Mercury TMDL - Mercury in Fish Tissue and Mercury in Water Column Impairments

· Mercury limits, monitoring, and mercury minimization plan requirements in the permit should be in accordance with the Mercury Permit Writers Guidance.

Lower Minnesota River Low Dissolved Oxygen TMDL · Wastewater WLAs are implemented through the Minnesota River General Phosphorus permit. This facility is

included in Appendix B of the General Phosphorus Permit: Continuous Discharge Permits with Calculated Phosphorus Loads Greater Than 1800 pounds per year. The limits in this Appendix specify the total phosphorus load permitted for each Permittee during the May 1st through September 30th period of each applicable calendar year. A trade ratio of 1.1 to 1 must be used.

· For facilities listed in Appendix B, the TMDL has a goal of one milligrams per liter (mg/L) for the year 2015. This is equivalent to the current permitted effluent phosphorus limit.

Draft Minnesota River Turbidity TMDL · Draft WLA for TSS = 209.00 kilograms per day (kg/day) (Appendix A-XVII) · This draft WLA is equivalent to the existing permitted effluent TSS limit.

Draft South Metro Mississippi TSS TMDL · Draft WLA for TSS = 76,285 kilograms per year and 209.00 kg/day (page 93) · The WLA is equivalent to the existing permitted effluent mass limit for TSS kg/day. · This facility is included in Appendix A.1. Minnesota Wastewater Permits with TSS Limits Less than or equal to

32 mg/L and Eligible for Future WLA Increase.

Draft Lake Pepin – Excess Nutrients TMDL · The discharge is located within the project area and the existing phosphorus limit is consistent with WLA

assumptions. · This discharge is located upstream of reaches of the Minnesota River that exceed river eutrophication standards.

The reaches are included in the recent Lake Pepin TMDL. Additional Information:

There are a number of Polychlorinated Biphenyls – Fish (PCBF), Perfluorooctane Sulfonate in Fish (PFOS-F) and Perfluorooctane Sulfonate in the water column (PFOS-W) impairments that were not specifically outlined in this review. TMDLs are not underway for PCBF or PFOS impairments at this time.

Existing permit effluent limits

Technology based effluent limits

The CBOD5 (April through November), TSS, potential of hydrogen (pH), and percent removal limits are technology based limits developed for achieving secondary treatment standards. These limits are specified in 40 CFR § 133.102, Minn. R. 7050.0211, and Minn. R. 7053.0215.

Water quality based effluent limits

Water Quality Based Effluent Limits in the existing permit have been developed for CBOD5 (December through March), Dissolved Oxygen (DO) (December through March), total residual chlorine, mercury, and phosphorus.

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NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 State Discharge Restrictions

The limit for fecal coliform has been developed to meet state discharge restrictions (SDRs) specified under Minn. R. 7053.0215, subp. 1. The 1.0 mg/L limit for total phosphorus is applicable under Minn. R. 7053.0255, Subp. 3.

Table 3: Current Limits and Monitoring Requirements

Parameter Limit Units Limit Type Effective Period Sample Type Frequency

Bicarbonates (HCO3) Monitor Only mg/L Calendar Month Maximum

Jan-Dec 24-Hour Flow Composite

1 x Month

CBOD5 104 kg/day Calendar Month Average Dec-Mar 24-Hour Flow Composite

3 x Week

CBOD5 15 mg/L Calendar Month Average Dec-Mar 24-Hour Flow Composite

3 x Week

CBOD5 174 kg/day Maximum Calendar Week Average

Dec-Mar 24-Hour Flow Composite

3 x Week

CBOD5 25 mg/L Maximum Calendar Week Average

Dec-Mar 24-Hour Flow Composite

3 x Week

CBOD5 174 kg/day Calendar Month Average Apr-Nov 24-Hour Flow Composite

3 x Week

CBOD5 25 mg/L Calendar Month Average Apr-Nov 24-Hour Flow Composite

3 x Week

CBOD5 279 kg/day Maximum Calendar Week Average

Apr-Nov 24-Hour Flow Composite

3 x Week

CBOD5 40 mg/L Maximum Calendar Week Average

Apr-Nov 24-Hour Flow Composite

3 x Week

CBOD5 % Removal 85 % Minimum Calendar Month Average

Jan-Dec Calculation 3 x Week

Calcium, Total Monitor Only mg/L Calendar Month Maximum


1 x Month

Chloride, Total Monitor Only mg/L Calendar Month Maximum


1 x Month

Chlorine, Total Residual 0.038 mg/L Daily Maximum Jan-Dec Grab 1 x Day

Fecal Coliform 200 #100ml Calendar Month Geometric Mean

Apr-Oct Grab 3 x Week

Flow Monitor Only mgd Calendar Month Average Jan-Dec Measurement, Continuous

1 x Day

Flow Monitor Only mgd Calendar Month Maximum

Jan-Dec Measurement, Continuous

1 x Day

Flow Monitor Only MG Calendar Month Total Jan-Dec Measurement, Continuous

1 x Day

Hardness, Calcium & Magnesium

Monitor Only mg/L Calendar Month Maximum


1 x Month

Magnesium, Total Monitor Only mg/L Calendar Month Maximum


1 x Month

Mercury, Total 70 mg/day Calendar Month Average Jan-Dec Grab 2 x Month

Mercury, Total 10 ng/L Calendar Month Average Jan-Dec Grab 2 x Month

Mercury, Total 120 mg/day Daily Maximum Jan-Dec Grab 2 x Month

Mercury, Total 17 ng/L Daily Maximum Jan-Dec Grab 2 x Month

Nitrite Plus Nitrate, Total Monitor Only mg/L Calendar Month Average Apr, Sep 24-Hour Flow Composite

1 x Month

Nitrogen, Ammonia, Total

Monitor Only mg/L Calendar Month Average Jan-Dec 24-Hour Flow Composite

1 x Month

Nitrogen, Kjeldahl, Total Monitor Only mg/L Calendar Month Average Apr, Sep 24-Hour Flow Composite

1 x Month

Oxygen, Dissolved 6.0 mg/L Calendar Month Minimum

Dec-Mar Grab 1 x Day


Oxygen, Dissolved Monitor Only mg/L Calendar Month Minimum

Apr-Nov Grab 1 x Day

pH 9.0 SU Calendar Month Maximum

Jan-Dec Grab 1 x Day

pH 6.0 SU Calendar Month Minimum

Jan-Dec Grab 1 x Day

Phosphorus, Total 1.0 mg/L 12 Month Moving Average


3 x Week

Phosphorus, Total 2036 kg/yr 12 Month Moving Total Jan-Dec 24-Hour Flow Composite

3 x Week

Phosphorus, Total Monitor Only mg/L Calendar Month Average Jan-Dec 24-Hour Flow Composite

3 x Week

Phosphorus, Total Monitor Only kg/mo Calendar Month Total Jan-Dec 24-Hour Flow Composite

3 x Week

Potassium, Total Monitor Only mg/L Calendar Month Maximum


1 x Month

Sodium, Total Monitor Only mg/L Calendar Month Maximum


1 x Month

Solids, Total Dissolved Monitor Only mg/L Calendar Month Maximum


1 x Month

TSS 209 kg/day Calendar Month Average Jan-Dec 24-Hour Flow Composite

3 x Week

TSS 30 mg/L Calendar Month Average Jan-Dec 24-Hour Flow Composite

3 x Week

TSS 313 kg/day Maximum Calendar Week Average


3 x Week

TSS 45 mg/L Maximum Calendar Week Average


3 x Week

TSS % Removal 85 % Minimum Calendar Month Average

Jan-Dec Calculation 3 x Week

Specific Conductance Monitor Only umh/cm Calendar Month Maximum

Jan-Dec Measurement 1 x Month

Sulfate, Total Monitor Only mg/L Calendar Month Maximum


1 x Month

Proposed permit effluent limits

Technology based effluent limits

The CBOD5 (April through November), TSS, pH, and percent removal limits are TBELs developed for achieving secondary treatment standards. These limits are specified in 40 CFR § 133.102, Minn. R. 7050.0211 and Minn. R. 7053.0215 subp. 1.

Water quality based limits

The WQBELs in the proposed permit have been developed for CBOD5 (December through March), dissolved oxygen (DO) (December through March), mercury, and total phosphorous (TP) (2036 kg/yr, 12-month moving total, and 5.4 kg/month, calendar month average). The limit for Total Residual Chlorine is applied per Minn. R. 7053.0225, Subp. 1.

CBOD5 and DO - Due to freezing stream temperatures organic pollutants decay at a much lower rate than in the summer months, but they still decay. In decaying, they consume oxygen. Under ice and snow cover aquatic plants are either dormant or produce insignificant amounts of oxygen. The ice cap is a physical barrier preventing atmospheric re-aeration. Under such conditions, if a stream’s headwater DO is depressed, it takes tens of miles for the DO to recover. This contrasts with about three to six miles during typical summer low dilution ratio conditions. Based on the agency’s historical winter field surveys results, it can take over 20-30 miles for a stream’s DO to recover to the headwater concentration during winter period. When DO was depressed below the five mg/L water quality standard, it took from

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 six to over 20 miles before the DO recovered to the five mg/L. Winter discharges have the potential to create a lengthy DO impact zone.

The DO sag from Mankato and Saint Peter will overlap the Le Sueur DO sag during winter period. To address this cumulative impact, a more stringent winter effluent CBOD5 concentration limit than the required secondary limit is assigned.

Mercury - The Minnesota River is listed on the 303(d) list of non-attainment waters for mercury. The non-attainment listing is based on fish consumption advice for mercury. 40 CFR 131.12(a)(1) provides that “existing instream uses and level of water quality necessary to protect the existing uses shall be maintained and protected”. This is the baseline protection provided by water quality standards, and water quality cannot be further degraded. Any new or increased discharge that would cause or contribute to a water quality standards violation cannot be allowed.

Phosphorus - The permit includes a proposed monthly average total phosphorus water quality based effluent limit (WQBEL) of 5.4 kg/d, June - September, to protect for eutrophication impairments in the Minnesota River and is consistent with river eutrophication standards (RES). The WQBEL of 5.4 kg/d is based off a five-year long-term average WLA of 2.59 kg/d, June - September. The long-term average WLA of 2.59 kg/d is based on achieving the RES of 0.150 mg/L in the Minnesota River (WID 07020012-799). The MPCA projects that by complying with the 5.4 kg/d monthly limit, the MRVPUC WWTF will have to average 2.59 kg/d, June - September, over a five-year long-term period. Upon conclusion of the permit cycle in which the facility’s 5.4 kg/d limit becomes effective; MPCA will evaluate the facility's discharge and the downstream water quality. In addition, if necessary, adjust the facility's 5.4 kg/d monthly average limit down to ensure that the long-term average WLA of 2.59 kg/d is achieved during the June - September effective period.

More information on the Total Phosphorus limits can be found on page 15 below.

State Discharge Restrictions The limit for fecal coliform has been developed to meet SDRs specified under Minn. R. 7053.0125, subp.1. The 1.0 mg/L phosphorus limit is a state discharge restriction set forth in Minn. R. 7053.0255, subp. 3.A.(3).

Table 4: SD002 Proposed Limits and Monitoring Requirements

Parameter

Discharge limitations Monitoring requirements

Limits and Units Frequency Sample type Effective period

Bicarbonates Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

CBOD5 174 calendar month average

279 maximum calendar week average

kilograms per day

25 calendar month average


milligrams per liter

3 times per week


Apr-Nov

CBOD5 104 calendar month average


kilograms per day




3 times per week


Dec-Mar

CBOD5 Percent Removal

85 minimum calendar month average percent once per month

Calculation Jan-Dec

Calcium, Total Monitor only. calendar month maximum milligrams per liter

once per month


Apr, Sep

Chloride, Total Monitor only. calendar month maximum milligrams per liter

once per month


Apr, Sep


Parameter



Fecal Coliform 200 calendar month geometric mean organisms per 100 milliliter

3 times per week

Grab Apr-Oct

Flow Monitor only. calendar month total

million gallons

Monitor only. calendar month average

Monitor only. calendar month maximum

million gallons per day

once per day

Measurement, Continuous

Jan-Dec

Hardness, Calcium & Magnesium

Monitor only. calendar month maximum milligrams per liter

once per month


Apr, Sep

Magnesium, Total

Monitor only. calendar month maximum milligrams per liter

once per month


Apr, Sep

Mercury, Dissolved

Monitor only. calendar month average

Monitor only. daily maximum nanograms per liter

twice per month

Grab Jan, Mar, May, Jul, Sep, Nov

Mercury, Total 10 calendar month average 17 daily maximum nanograms per liter

twice per month


Nitrite Plus Nitrate

Monitor only. calendar month average milligrams per liter

once per month


Jan-Dec

Nitrogen, Ammonia


once per month


Jan-Dec

Nitrogen, Kjeldahl,


once per month


Jan-Dec

Nitrogen, Total Monitor only. calendar month average milligrams per liter

once per month


Jan-Dec

Oxygen, Dissolved

Monitor only. calendar month minimum milligrams per liter

once per day

Grab Apr-Nov

Oxygen, Dissolved

6.0 calendar month minimum milligrams per liter once per day

Grab Dec-Mar

pH 6.0 calendar month minimum 9.0 calendar month maximum standard units

once per day

Grab Jan-Dec

Potassium, Total Monitor only. calendar month maximum milligrams per liter once per month


Apr, Sep

Phosphorus, Total (as P) Phase 1

Monitor only. calendar month average kilograms per day once per week


Jan-Dec


Monitor only. calendar month average kilograms per day once per week


Oct-May


5.4 calendar month average* kilograms per day once per month


Jun-Sep

Phosphorus, Total (as P)

2036 12-month moving total

kilograms per year 1.0 12-month moving average


once per month

Calculation Jan-Dec

Phosphorus, Total (as P)

Monitor only. calendar month average milligrams per liter once per week


Jan-Dec

Sodium, Total Monitor only. calendar month maximum milligrams per liter once per month


Apr, Sep


Parameter




Monitor only. calendar month average Monitor only. calendar month maximum


once per month


Apr, Sep

Solids, Total Suspended (TSS)



kilograms per day




3 times per week


Jan-Dec

TSS Percent Removal

85 minimum calendar month average percent once per month

Calculation Jan-Dec

TSS, grab (Mercury)

Monitor only. calendar month average Monitor only. daily maximum milligrams per liter

twice per month


Specific Conductance

Monitor only. calendar month maximum micromhos per cm

once per month

Measurement Apr, Sep

Sulfate, Total Monitor only. calendar month maximum milligrams per liter

once per month


Apr, Sep

*The 5.4 kg/day limit for total phosphorus, June - September will become effective at Phase 2 of the permit, 10 years after permit issuance or as soon as possible. All other parameters are applicable during all phases of the permit.

Reasonable Potential for Chemical Specific Pollutants (40CFR§122.44(d)(1))

Federal regulations require the MPCA to evaluate the discharge to determine whether it has the reasonable potential to cause or contribute to a violation of water quality standards. The Agency must use acceptable technical procedures, accounting for variability (coefficient of variation (CV), when determining whether the effluent causes, has the reasonable potential to cause, or contribute to an excursion of an applicable water quality standard. Projected effluent quality (PEQ) derived from effluent monitoring data is compared to Preliminary Effluent Limits (PELs) determined from mass balance inputs. Both determinations account for effluent variability. Where PEQ exceeds the PEL, there is reasonable potential to cause or contribute to a water quality standards excursion. When reasonable potential is indicated, the permit must contain a WQBEL for that pollutant.

The priority pollutant scan information of the effluent was reviewed. No organic other than Bromodichloromethane, chloroform, dibromochoromethane and Beta-Benzene hexachloride (Beta-BHC) were above the detection level. The first three compounds are the result of chlorination. Beta-BHC (CAS number 319-85-7 or more correctly, β-HCH) is a byproduct of the production of the insecticide Lindane (γ-HCH). Lindane was used in agriculture from the mid-1940s to the 2000s. It has been banned since 2007 for agricultural uses in the USA. In 2009, an international ban on the use of Lindane in agriculture was implemented under the Stockholm Convention on Persistent Organic Pollutants (Wikipedia, May 9, 2016) however, Lindane is still permitted in the U.S.A. as second-line lice and scabies treatment. Lindane is persistent in the environment; it bioaccumulates, it biomagnifies and it has a long-range transport capacity.

No additional monitoring will be requested at this time. The priority pollutant scans will be examined on the next permit cycle; if there are two or more values of β-HCH above the detection level the need for water quality based limits for β-HCH will be assessed. The other organic pollutants are below the level of detection and no reasonable potential analysis could be conducted.

Table 5 below contains the inputs to the reasonable potential analysis for copper (Cu) and nickel (Ni) and the outputs of the analysis. These were the only two metals that were above the level of detection in the four priority pollutant scans. There were no measurements of Cu and Ni in the receiving water upstream of the facility. The water samples were

https://en.wikipedia.org/wiki/Insecticide

https://en.wikipedia.org/wiki/Lindane

https://en.wikipedia.org/wiki/Stockholm_Convention_on_Persistent_Organic_Pollutants

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 taken in the Minnesota River at station S000-040 (Minnesota River at the MN-19 Bridge at the city of Henderson) from 1968-1998. There were 120 measurements for Cu and 113 measurements for Ni, the median of the Cu and the median of the Ni measurements were, in both cases, non-detect at a reported level of 10 micrograms per Liter (ug/L). A value of 10 ug/L was used as the background for both metals. This is a conservative approach. Table 5 below shows that there is no reasonable potential for any of the parameters and no water quality based limits are needed.

Table 5. Analysis of reasonable potential for Cu and Ni

Parameter Cu (ug/L) Ni (ug/L)

Maximum measured value 22.5 30.9 # data points 4 4 Projected effluent quality (PEQ) 45 61.8

Facility Average Dry Weather Design Flow(mgd) 1.26 1.26

Receiving water flow, 7Q10(mgd) 119.8 119.8

Background concentration 10 10

Chronic standard (cs) 24.6 552.2 440 parts per million (ppm) hardness

Maximum standard (ms) 72 4967 440 ppm hardness

Final acute value (FAV) 100 7164 229 ppm hardness

Mass balance -cs 1421 52329

Mass balance -ms 5953 478350

Coefficient of variation (CV) 0.6 0.6

Long term average - cs 750 27600

Long term average - ms 1912 153596

Preliminary effluent limits: Daily maximum 2335 85955 Monthly average (2 x month) 1348 49615

Reasonable potential PEQ >Daily maximum FALSE FALSE PEQ >Monthly Average FALSE FALSE PEQ > FAV FALSE FALSE Final Reasonable Potential No No

Table 6 below contains the inputs to the reasonable potential analysis for the salty parameters: bicarbonates, hardness, chloride (Cl), sulfate, total dissolved solids (TDS), and specific conductance (SC) and the outputs of the analysis. The alkalinity, hardness and specific conductance of the receiving water upstream of SD002 were obtained from the whole effluent toxicity test (2011-2015, 54 samples). Alkalinity was used as a surrogate for bicarbonate. The chloride and sulfate concentrations were measured a total of nine times each during the months of May, June, July, August, and September 2014 and 2015 at station S007-860, upstream of U.S. Highway 169. The median chloride and sulfate concentrations were 22.8 and 161 mg/L, respectively. Table 6 below shows that there is no reasonable potential for any of the parameters and no WQBELs are needed.

The facility receives a waste stream from a cheese factory. It is recommended that the salty parameters are monitored twice per year, in April and September.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Table 6. Analysis of reasonable potential for the salty parameters

Parameter Bicarbonates as HCO3 (mg/L)

Hardness (mg/L)

Class 2 Cl (mg/L)

Class 3 Cl (mg/L)

Sulfate (mg/L)

TDS (mg/L)

SC (umhos/cm)

Maximum measured value 828 368 936 936 132 2000 3520 # data points 51 105 51 51 51 49 51 PEQ 828 368 936 936 132 2000 3520

Plant Average Dry Weather Flow (mgd) 1.255 1.255 1.255 1.255 1.255 1.255 1.255

Rec. water flow, 7Q10 (mgd) 119.8 119.8 119.8 119.8 119.8 119.8 119.8

Background concentration 254 440 22.8 22.8 161 675.2 844

Chronic standard (cs) 305 500 230 250 1000 700 1000

Maximum standard (ms) NA NA 860.00 NA NA NA NA

Final acute value (FAV) NA NA 1720 NA NA NA NA Mass balance - cs 5175 6230 20016 21946 81119 3068 15897

Mass balance - ms NA NA 80807.50 NA NA NA NA

Coefficient of variation 0.35 0.11 0.17 0.17 0.10 0.08 0.09

Long term average - cs 4462 5955 16574 20467 77919 2969 15323

Long term average - ms NA NA 55886 NA NA NA NA

Preliminary effluent limits: Daily maximum 9362 7582 23966 29594 96738 3546 18678 Monthly average (2 x month) 6496 6721 19943 24626 86832 3245 16919

Reasonable potential PEQ > Daily maximum FALSE FALSE FALSE FALSE FALSE FALSE FALSE PEQ > Monthly average FALSE FALSE FALSE FALSE FALSE FALSE FALSE PEQ > FAV NA NA FALSE NA NA NA NA Final reasonable potential No No No No No No No

Whole Effluent Toxicity

The Permittee has acute Whole Effluent Toxicity (WET) monitoring as a requirement, because the ratio of the Minnesota River annual 7Q10 low flow (the lowest consecutive seven-day flow that a river experiences on average at least once every 10 years, which for this portion of the Minnesota River is 119.8 mgd) to the facility’s average dry weather design flow, which for this facility is 1.26 mgd) is greater than 20:1. A monitoring threshold value of 0.9999 Acute Toxicity Units (TUa) has been established. The 0.9999 TUa is a threshold value, not a WET limit. The facility has submitted nine WET tests and four priority pollutant scans since June 2011. None of them showed toxicity.

Phosphorus

Although not required during this permit cycle, the Permittee will be required to meet a Total Phosphorus limit of 5.4 kg/day by ten years after permit issuance. The permit contains a compliance schedule for the Permittee to work toward compliance with that limit.

The TP concentration in the Minnesota River measured at a representative site near the outlet of the watershed in St. Peter indicates that it is above the RES at the critical 80 percent exceeds flow (a relatively low stream flow that is exceeded 80 percent of the time) (Figure 1). Hydrological Simulation Program-Fortran (HSPF) model based limits for the Lower Minnesota River at historical flows are protective of the Minnesota River at the critical 80 percent exceeds flow near the outlet of the Minnesota River – Mankato Watershed (Figure 2). Additional non-point reductions will be needed to meet RES as a long-term average.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Figure 1: Monitored daily summer (June-September) total phosphorus load of the Minnesota River at St. Peter (station S000-041) from 2004-2012. Percent exceeds flow based on 1984-2013 summer flows (Minnesota River at Mankato). Concentration at critical flow = 0.189 mg/L (n=5). Blue line represents load at RES (0.150 mg/L).

Flow (% Exceeds)

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Figure 2: Daily summer (June-Sept) total phosphorus predicted by HSPF for the Minnesota River at St. Peter from 1993 – 2006 excluding 2000. Note Total Phosphorus (TP) data is arranged by flow (percent exceeds) for the Minnesota River based on the summer flow from 1993-2006. The river eutrophication standard is 0.150 mg/L.

A low dissolved oxygen TMDL for the lower Minnesota River established individual TP allocations as kg/day for 40 wastewater treatment facilities in the Minnesota River Basin (Gunderson and Klang 2004). This TMDL was designed to protect the last 22 miles of the Minnesota River from excessive Biochemical Oxygen Demand (BOD) loading during summer from the Minnesota River upstream of Jordan, Minnesota. Excess BOD loading was the result of algal production in the Minnesota River driven by elevated concentration of TP. Recent reductions of TP loading from point sources in the Minnesota River Basin have been driven by a variety of permit requirements including those included in the Minnesota River Basin General Phosphorus Permit Phase I (General Permit) (http://www.pca.state.mn.us/index.php/view-document.html?gid=5997). The WLA for MRVPUC under this permit includes the entire allocations from the city of Le Sueur (5.2 pounds per day (lbs/day), the city of Henderson (2.1 lbs/day), and part of Agropur’s (formerly known as Le Sueur Cheese) allocation (4.2 lbs/day of Agropur’s 4.6 lb/day allocation). Agropur has an allocation to discharge 0.18 kilograms/day (0.40 lbs/day) of phosphorus at their remaining permitted discharge. The remainder of their WLA has been accredited to MRVPUC. Therefore, MRVPUC’s WLA is the sum of the following allocations: 5.2 lbs/day from Le Sueur, 2.1 lbs/day from Henderson, and 4.2 lbs/day from Agropur (4.6lbs/day-0.4lbs/day) for a sum of 11.5 lbs/day or 5.22kg/day.


NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 The RES WLA for MRVPUC that has more recently been calculated under the Phosphorus Effluent Limit Review: Minnesota River Basin Memo is 2.59 kg/day. Ultimately, the RES based limits for MRVPUC in the 10th year of the proposed draft permit are more restrictive than the General Permit requirements.

In addition, and included below, is an excerpt from the MPCA guidance on Interpreting WLAs for the Development of WQBELs (MPCA 2009).https://www.pca.state.mn.us/sites/default/files/wq-iw1-32.pdf.

Additional requirements

Compliance Schedule

According to Minn. Statute Section 115.456, the MPCA must consider the municipality’s current debt service on municipal wastewater treatment infrastructure when including a compliance schedule in permits. MRVPUC (data combines the financial information for both Le Sueur and Henderson) currently has debt on their existing WWTP that is not scheduled to be retired for 8 years. The MRVPUC’s existing wastewater treatment infrastructure cost (including both debt service and operation and maintenance costs) is higher than the affordability criteria outlined in state and federal regulations, when expressed as a percentage of medium household income.

The MRVPUC has determined that it cannot meet the 5.4 kg/day total phosphorus limit (applicable June-September) immediately upon permit reissuance. The MPCA staff have assessed the facility’s past effluent phosphorus loading and concur that it cannot immediately meet the new limit consistently on a monthly basis. As a result of this determination, the permit contains a compliance schedule to meet a 5.4 kg/day total phosphorus limit, applicable June-September, as soon as possible, but no later than ten years after permit issuance. A ten-year compliance schedule was placed in the permit to allow the facility time to reduce current debt service. Additionally, the compliance schedule will allow time to optimize facility performance, reduce phosphorus sources, and if necessary, plan for potential facility upgrades. The schedule includes the submittal of annual reports which detail the work which was completed in the previous year, and the work which is planned to be completed in the coming year toward compliance with the limit, along with submittal of the MRVPUC and its member cities’ current debt loads and financial status.

Pollutant minimization plans

The Permittee is required to submit a MMP. The MMP requirements include educating users with regard to proper mercury disposal in order to prevent its introduction into the waste stream.

Industrial Stormwater

On April 5, 2015, the Industrial Stormwater General Permit (MNR050000) was issued. This permit addresses stormwater discharges associated with industrial activity for facilities that discharge stormwater to waters of the state, including Municipal Separate Storm Sewer Systems. The General Permit also addresses stormwater discharges associated with industrial activities at facilities that provide on-site infiltration of industrial stormwater discharges associated with the facility.

For both industrial and municipal wastewater facilities, in lieu of obtaining coverage under both the General Permit and the individual NPDES Permit, the MPCA has added the necessary industrial stormwater requirements language and limits and monitoring to this permit so that coverage under this NPDES permit alone will cover both permits. This facility has applied for and obtained a Certification of No Exposure; therefore, this permit includes language regarding the No Exposure exclusion.

https://www.pca.state.mn.us/sites/default/files/wq-iw1-32.pdf

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance of 21 Total facility requirements

All NPDES/SDS Permits issued in the state of Minnesota contain certain conditions that remain the same regardless of the size, location, or type of discharge. The standard conditions satisfy the requirements outlined in 40 CFR § 122.41, Minn. R. 7001.0150, and Minn. R. 7001.1090. These conditions are listed in the Total facility Requirements chapter of the NPDES/SDS Permit. These requirements cover a wide range of areas, including recordkeeping, sampling, equipment calibration, equipment maintenance, reporting, facility upsets, bypass, solids handling, changes in operation, facility inspections, and permit modification and reissuance.

Antidegradation and anti-backsliding

Changes to the facility may result in an increase in pollutant loading to surface waters or other causes of degradation to surface waters. If a change to the facility will result in a net increase in pollutant loading or other causes of degradation that exceed the maximum loading authorized through conditions specified in the existing permit, the changes to the facility are subject to antidegradation requirements found in Minn. R. 7050 to 7050.0335.

This permit also complies with Minn. R. 7053.0275 regarding anti-backsliding.

Any point source discharger of sewage, industrial, or other wastes for which a NPDES permit has been issued by the agency that contains effluent limits more stringent than those that would be established by Minn. R. 7053.0215 to 7053.0265 shall continue to meet the effluent limits established by the permit, unless the permittee establishes that less stringent effluent limits are allowable pursuant to federal law, under section 402(o) of the Clean Water Act, United States Code, title 33, section 1342.

https://www.revisor.leg.state.mn.us/rules?id=7053.0215

https://www.revisor.leg.state.mn.us/rules?id=7053.0265

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