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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

P.O. Box 176 Le Sueur, Minnesota 56058-0176

Facility name: Minnesota River Valley Public Utilities Commission Wastewater Treatment Facility 1500 Commerce Street Le Sueur, Minnesota 56058-1118 Current permit expiration date: October 31, 2016 Public comment period begins: October 14, 2016 Public comment period ends: November 14, 2016 Receiving water: Minnesota River - Class 2B, 3C, 4A, 4B, 5, 6 water Permitting contact: Nancy Heskett 18 Wood Lake Drive Southeast

Rochester, Minnesota 55904 507-206-2605 nancy.heskett@state.mn.us

MN0068195 Page 2 of 20

Table of Contents 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) .................................................................................................................................................................................................. 8 Use classification ................................................................................................................................................................ ................................. 8 Impairments ................................................................................................................................................................................................ .......... 8 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) ........................................................................................................................................................... 10 Table 3 : Current Limits and Monitoring Requirements ..................................................................................................................... 11

Proposed permit effluent limits ...................................................................................................................................................................... 12 Technology Based Limits ................................................................................................................................................................................ 12 Water Quality Based Limits ........................................................................................................................................................................... 12

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

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)).......................................................................... 14 Table 5. Analysis of reasonable potential for Cu and Ni ........................................................................................................................ 15 Table 6. Analysis of reasonable potential for the salty parameters .................................................................................................. 16 Whole Effluent Toxicity ................................................................................................................................................................ ..................... 16 Phosphorus ................................................................................................................................................................ ........................................... 16

Figure 1: ................................................................................................................................................................ ........................................... 17 Figure 2: ................................................................................................................................................................ ........................................... 18

Additional requirements ....................................................................................................................................................................................... 19 Pollutant minimization plans (PMP) ............................................................................................................................................................. 19 Industrial Stormwater ....................................................................................................................................................................................... 19 Total facility requirements............................................................................................................................................................................... 19 Nondegredation and anti-backsliding ......................................................................................................................................................... 19

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 3 of 20 Purpose and participation Applicable statutes This fact sheet has been prepared according to the 40 CFR § 124.8, 40 CFR § 124.56 and Minn R. 7001.0100, subp. 3 in regard 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 1 through 3 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, Minnesota 55904

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 4 of 20 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 Le Sueur Cheese 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 Le Sueur Cheese 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. 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 Facility is an existing municipal wastewater treatment facility that treats wastewater from the communities of Le Sueur and Henderson. The Facility and outfall (SD002) is 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.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 5 of 20 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 Page 6 of 20 Flow schematic

Changes to facility or operation The Facility completed decommissioning of the Le Sueur wastewater treatment facility stabilization ponds in 2013 and that individual permit was terminated. Significant industrial users (SIUs) The Permittee receives process wastewater from one SIU, Le Sueur Cheese Agropur. The Permittee holds a contract with this SIU to limit and monitor pollutants of concern. Recent compliance history The Facility was last inspected on March 31, 2016. Industrial Stormwater, Biosolids, and Wastewater were inspected. Currently this facility claims exemption from the Industrial Stormwater Permit under “no exposure.” In order for them to keep this status the Regulated Party must berm around the perimeter of the Biosolids storage area. Nine effluent violations were noted; five of those are minor deviations away from Total Suspended Solids (TSS) percent removal and another three are also TSS violations for the same period related to a SIU contributing to the load. The last exceedance was in 2014 and it appears to be under control. Unauthorized re-use of wastewater was also discovered. For a number of years (as long as the Operator could think) the Facility has been pumping water out of their chlorine contact basin after the point of chlorine introduction, but before dechlorination is added. Water was reported to be used for irrigation around city property and also on roads. Recent monitoring history The following table shows the average monthly reported values by the Facility from January through December, 2015. Where no number is given in the Limit and Units column, the Facility is required to monitor only for that parameter.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 7 of 20 Table 1: Recent monitoring history Parameter Units Limit Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Bicarbonates mg/L 403 508 451 405 551 562 511 678 640 695 709 737

CBOD5 kg/d 104 9.2 8.9 6.9 7.9

CBOD5 kg/d 174 7.8 9.1 7.1 6.7 8.7 5.9 6.8 7.8

CBOD5 mg/L 15 2.1 2.1 1.6 1.6

CBOD5 mg/L 25 1.8 2.2 1.5 1.4 1.9 1.2 1.5 1.6

CBOD5 kg/d 174 14 12 7.6 15

CBOD5 kg/d 279 8.8 18 8.9 9.1 18 11 16 17

CBOD5 mg/L 25 3.5 2.8 1.9 3.2

CBOD5 mg/L 40 1.9 4.3 1.8 1.9 3.9 2.2 3.3 3.5

CBOD5 % Removal % 85 99 98 99 99 98 99 99 98 98 98 98 99

Calcium, Total mg/L 81 58 69 65 63 96 56 73 80 86 91 101

Chloride, Total mg/L 851 750 760 936 808 660 582 553 599 484 506 506

Chlorine, Total Residual

mg/L 0.038 0.016 0.034 0.026 0.035 0.022 0.032 0.02

Fecal Coliform #/100ml 200 12 34 36 23 41 34 28

Flow mgd 1.2 1.1 1.1 1.1 1.1 1.2 1.3 1.2 1.244 1.194 1.277 1.302

Flow mgd 1.3 1.2 1.3 1.3 1.4 1.4 1.9 1.4 1.73 1.31 1.476 1.478

Flow Mgal 36 32 35 34 35 37 41 38 37.32 37.01 38.30 40.37

Hardness, Calcium & Magnesium

mg/L 312 247 267 260 248 343 222 283 289 300 323 342

Magnesium, Total mg/L 27 248 23 24 22 25 20 24 22 21 24 22

Mercury, Total mg/d 70 2.3 2.2 2.08 1.8 2.08 2.3 3 2.3

Mercury, Total mg/d 70 2.4 2.3 2.6 2.6

Mercury, Total ng/L 10 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

Mercury, Total mg/d 120 2.5 2.33 2.46 2 2.65 2.65 3.6 2.6

Mercury, Total mg/d 120 2.4 2.4 2.6 2.8

Mercury, Total ng/L 17 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

Nitrite Plus Nitrate, Total

mg/L 26 22

Nitrogen, Ammonia, Total

mg/L 0.27 0.1

Nitrogen, Ammonia, Total

mg/L 0.1 0.1 10 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Nitrogen, Kjeldahl, Total

mg/L 2.2 2.7

Oxygen, Dissolved mg/L 6.6 6.2 6.4 6.1 7.1 7.4 7.2 7.6

Oxygen, Dissolved mg/L 6 6.4 6.7 6.3 7.2

pH SU 9 8.3 8.2 8.2 7.8 8 7.9 7.9 7.9 7.9 8.2 8.4 8.4

pH SU 6 6.9 6.6 7.1 7 7.3 6.8 7.1 7.1 7.2 7.2 7.4 7.6

Phosphorus, Total mg/L 1 0.75 0.73 0.72 0.73 0.72 0.72 0.72 0.7 0.71 0.55 0.73 0.63

Phosphorus, Total kg/yr 2,036 1,335 1287 1,138 1135 1125 1091 1078 1087 1,099 1177 898 931

Phosphorus, Total mg/L 1 0.51 0.63 0.86 0.53 0.36 0.43 0.42 0.5 0.55 0.7 1.1

Phosphorus, Total kg/mo 141 62 84 112 70 51 68 61 71 77 101 174

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 8 of 20 Potassium, Total mg/L 188 179 174 181 220 208 176 184 169 177 165 160

Sodium, Total mg/L 498 495 474 473 719 806 449 513 565 558 555 559

Solids, Total Dissolved mg/L 2,000 1,880 20 16 1,860 1,770 1,500 1,700 1,760 1,780 1,790 1,700

Solids, Total Suspended (TSS)

kg/d 209 108 52 76 96 96 67 36 34 31 59 41 40

TSS mg/L 30 25 12 18 22 23 14 7.3 7.1 6.4 13 8.3 8.1

TSS kg/d 313 176 73 92 112 116 116 47 36 35 139 59 53

TSS mg/L 45 44 17 23 25 27 24 9 7.7 7 30 12 10

TSS % Removal % 85 97 98 98 97 96 98 99 99 98 95 97 99

Specific Conductance Umhos /cm

3,520 3,350 3,270 3,210 3,110 3,060 2,560 2,870 2,870 2,660 2,830 2,780

Sulfate, Total mg/L 116 105 120 111 102 100 86 107 93 106 99 117

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.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 9 of 20 Table 2: Impaired Waters and TMDL Status Downstream Impairments Number of

Impairments TMDL Status

Minnesota River 31

Mercury in Fish Tissue 8 See the WLA 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 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 but have not officially been listed at 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 below.

PCBF 3 See the Additional Information below.

Grand Total 60

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

· Mercury limits, monitoring, and MMP 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 lbs/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.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 10 of 20

· 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 (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 kg/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 (TBELs) 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 (WQBELs) Water Quality Based Effluent Limits in the existing Permit have been developed for CBOD5 (December through March), Dissolved Oxygen (DO) (December through March), mercury, and total phosphorus. The phosphorus limit is derived from the draft WLA which in turn is derived from the water quality standard that the receiving water must meet to achieve designated uses. State Discharge Restrictions (SDRs) The limit for fecal coliform has been developed to meet state discharge restrictions specified under Minn. R. 7053.0215, subp. 1.

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 11 of 20 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 Jan-Dec 24-Hour Flow Composite 1 x Month

Chloride, Total Monitor Only mg/L Calendar Month Maximum Jan-Dec 24-Hour Flow Composite 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 Jan-Dec 24-Hour Flow Composite 1 x Month

Magnesium, Total Monitor Only mg/L Calendar Month Maximum Jan-Dec 24-Hour Flow Composite 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 Jan-Dec 24-Hour Flow Composite 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 Jan-Dec 24-Hour Flow Composite 1 x Month

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 12 of 20 Sodium, Total Monitor Only mg/L Calendar Month Maximum Jan-Dec 24-Hour Flow Composite 1 x Month

Solids, Total Dissolved

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

Jan-Dec 24-Hour Flow Composite 3 x Week

TSS 45 mg/L Maximum Calendar Week Average

Jan-Dec 24-Hour Flow Composite 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 Jan-Dec 24-Hour Flow Composite 1 x Month

Proposed permit effluent limits

Technology Based Limits The CBOD5 (April through November), TSS, 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 subp. 1. Water Quality Based Limits The WQBELs in the existing Permit have been developed for CBOD5 (December through March), dissolved oxygen (DO) (December through March), mercury, and total phosphorus. The 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 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 Minnesota River from the outlet of Lac qui Parle Reservoir to the Minnesota River at Fort Snelling has multiple reaches that exceed river eutrophication standards (RES). The June – September phosphorus limit is a RES standard which is more restrictive than the five-month total mass limit that the Facility has under the lower

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 13 of 20 Minnesota River low DO TMDL. In addition, the Facility also discharges upstream of Lake Pepin. The WQBEL allocated to this Facility for Lake Pepin is an annual limit (kilograms per year, or kg/yr) assessed as a 12-month moving total. State Discharge Restrictions (SDRs) The limit for fecal coliform has been developed to meet state discharge restrictions 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

Limit and Units Frequency Sample type Effective period Bicarbonates (HCO3) Monitor only. calendar month maximum milligrams per

liter once per month

24-Hour Flow Composite

Apr, Sep

BOD, Carbonaceous 05 Day (20 Deg C)

25 calendar month average

40 maximum calendar week average

milligrams per liter

3 times per week

24-Hour Flow Composite

Apr-Nov

BOD, Carbonaceous 05 Day (20 Deg C)

174 calendar month average

279 maximum calendar week average

kilograms per day

3 times per week

24-Hour Flow Composite

Apr-Nov

BOD, Carbonaceous 05 Day (20 Deg C)

15 calendar month average

25 maximum calendar week average

milligrams per liter

3 times per week

24-Hour Flow Composite

Dec-Mar

BOD, Carbonaceous 05 Day (20 Deg C)

104 calendar month average

174 maximum calendar week average

kilograms per day

3 times per week

24-Hour Flow Composite

Dec-Mar

BOD, Carbonaceous 05 Day % Removal

85 minimum calendar month average percent 3 times per week

Calculation Jan-Dec (Sep-Aug) (Oct-Sep)

Calcium, Total (as Ca) Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

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

once per month

24-Hour Flow Composite

Apr, Sep

Chlorine, Total Residual 0.038 daily maximum milligrams per liter

once per day

Grab Jan-Dec (Sep-Aug) (Oct-Sep)

Fecal Coliform, MPN or Membrane Filter 44.5C

200 calendar month geometric mean organisms per 100 milliliter

3 times per week

Grab Apr-Oct

Flow Monitor only. calendar month average

Monitor only. calendar month maximum

million gallons per day

once per day

Measurement, Continuous

Jan-Dec (Sep-Aug) (Oct-Sep)

Flow Monitor only. calendar month total million gallons once per day

Measurement, Continuous

Jan-Dec (Sep-Aug) (Oct-Sep)

Hardness, Calcium & Magnesium, Calculated

Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

Magnesium, Total (as Mg)

Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

Mercury, Dissolved (as Hg)

Monitor only. calendar month average

Monitor only. calendar month maximum

nanograms per liter

twice per month

Grab Feb, Apr, Jun, Aug, Oct, Dec

Mercury, Total (as Hg) 10 calendar month average

17 calendar month maximum

nanograms per liter

twice per month

Grab Feb, Apr, Jun, Aug, Oct, Dec

Nitrite Plus Nitrate, Total (as N)

Monitor only. calendar month average milligrams per liter

once per month

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

Nitrogen, Ammonia, Total (as N)

Monitor only. calendar month average milligrams per liter

once per month

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

Nitrogen, Kjeldahl, Total

Monitor only. calendar month average milligrams per liter

once per month

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

Nitrogen, Total (as N) Monitor only. calendar month average milligrams per liter

once per month

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

Oxygen, Dissolved 6.0 calendar month minimum milligrams per liter

once per day

Grab Dec-Mar

Oxygen, Dissolved Monitor only. calendar month minimum milligrams per liter

once per day

Grab Apr-Nov

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 14 of 20 pH 6.0 calendar month

minimum 9.0 calendar month maximum

standard units once per day

Grab Jan-Dec (Sep-Aug) (Oct-Sep)

Phosphorus, Total (as P)

Monitor only. calendar month average milligrams per liter

once per week

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

Phosphorus, Total (as P)

5.4 calendar month average kilograms per day

once per week

24-Hour Flow Composite

Jun-Sep

Phosphorus, Total (as P)

2036 12-month moving total

kilograms per year

1.0 12-month moving average

milligrams per liter

once per month

Calculation Jan-Dec (Sep-Aug) (Oct-Sep)

Potassium, Total (as K) Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

Sodium, Total (as Na) Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

Solids, Total Dissolved (TDS)

Monitor only. calendar month average milligrams per liter

once per month

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

Solids, Total Suspended (TSS)

30 calendar month average

45 maximum calendar week average

milligrams per liter

3 times per week

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

TSS 209 calendar month average

313 maximum calendar week average

kilograms per day

3 times per week

24-Hour Flow Composite

Jan-Dec (Sep-Aug) (Oct-Sep)

TSS % Removal 85 minimum calendar month average percent 3 times per week

Calculation Jan-Dec (Sep-Aug) (Oct-Sep)

TSS, grab (Mercury) Monitor only. calendar month maximum milligrams per liter

twice per month

Grab Feb, Apr, Jun, Aug, Oct, Dec

Specific Conductance Monitor only. calendar month maximum micromhos per cm

once per month

Grab Apr, Sep

Sulfate, Total (as SO4) Monitor only. calendar month maximum milligrams per liter

once per month

24-Hour Flow Composite

Apr, Sep

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-

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 15 of 20 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 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

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 16 of 20 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 milligrams per Liter (mg/L), respectively. Table 6 below shows that there is no reasonable potential for any of the parameters and no water quality based limits are needed. The Facility receives a waste stream from a cheese factory. It is recommended that the salty parameters are monitored twice per year: April and September. 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. The Permittee has acute WET testing 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 Total Phosphorus (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 River Eutrophication Standard (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

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 17 of 20 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. 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 Page 18 of 20 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 Total Maximum Daily Load (TMDL) for the lower Minnesota River established individual TP allocations as kilograms per day (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 (http://www.pca.state.mn.us/index.php/view-document.html?gid=5997). The WLA assigned to the MRVPUC Facility under this TMDL is 2.37 kg/day. The aggregate sum of the River Eutrophication Standards (RES) based allocations assigned in the draft Lake Pepin Watershed Nutrient TMDL for the original 40 facilities in the low dissolved oxygen TMDL is more restrictive than the aggregate sum of the allocations in the low dissolved oxygen TMDL. The low dissolved TMDL allocations were based on a universal concentration multiplier while the RES based limits were based on a categorical concentration multiplier which varies by facility size. As a result, although some of the smaller facilities have less restrictive individual RES WLAs, the aggregate sum for all the facilities is approximately 60 kg/day less than the low DO TMDL. Given that the low DO reach of the Minnesota River is downstream of all the facilities and the aggregate sum of the RES allocations is more restrictive

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 19 of 20 than the Lower Minnesota River Low Dissolved Oxygen TMDL’s WLAs, the RES based TP WLAs will be the basis for summer effluent TP limits. Facilities will not need coverage under the Minnesota Basin Permit once their individual NPDES permits contain RES based summer TP effluent limits. The MRVPUC Facility’s new 5.4 kg/day summer TP effluent limit is derived from the RES based 2.37 kg/day WLA, which is considerably more restrictive than the load that was allocated to the three original dischargers it replaced (Henderson Wastewater Treatment Plant (WWTP), Le Sueur WWTP, and Le Sueur Cheese WWTP) which had combined WLAs of 11.9 lb/day. 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

Pollutant minimization plans The Permittee is required to submit a Mercury Minimization Plan (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. 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. Nondegredation and anti-backsliding In accordance with MPCA rules regarding nondegredation for all waters (that are not Outstanding Resource Value Waters), nondegredation review is required for any new or expanded significant discharge (Minn. R. 7050.0185). A significant discharge is: (1) a new discharge (not in existence before January 1, 1988) that is greater than 200,000 gallons per day (gpd) or; (2) an expanded discharge that expands by greater than 200,000 gpd that discharges to any non-outstanding resource value water other than a Class 7 water or; (3) a new or expanded discharge containing any toxic

NPDES/SDS Permit Program Fact Sheet MN0068195 Permit Reissuance Page 20 of 20 pollutant at a mass loading rate likely to increase the concentration of the toxicant in the receiving water by greater than one percent over the baseline quality. 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 Minn. R. 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.