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

Transcription

1 National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) Permit Program Fact Sheet Permittee: City of Willmar Facility Name: Willmar WWTF Permit Number: MN P.O. Box th Street Southeast Willmar, MN Willmar, MN Current Permit Expiration: February 28, 2013 Public Comment Period Begins: May 1, 2015 Period Ends: June 1, 2015 Receiving Water: Hawk Creek (Class 7, 3C, 4A, 4B, 5, 6 Water) Proposed Action: Reissuance Permitting Contact Ashley Wahl 504 Fairgrounds Road, Suite 200 Marshall, Minnesota Phone: Fax:

2 Table of Contents Purpose and Participation... 3 Applicable Statutes... 3 Fact Sheet Purpose... 3 Public Participation... 3 Facility Description... 4 Facility Outfall and Location... 4 Map of Permitted Facility... 5 Components and Treatment Technology... 6 Flow Schematic... 7 Significant Industrial Users... 8 Recent Compliance History... 8 Recent Monitoring History Receiving Water Use Classification Impairments Existing Permit Effluent Limits State Discharge Restrictions Technology Based Effluent Limits Water Quality Based Effluent Limits Proposed Permit Effluent Limits State Discharge Restrictions Technology Based Effluent Limits Water Quality Based Effluent Limits Priority Pollutants and Acute Whole Effluent Toxicity (WET) Testing Reasonable Potential for Chemical Specific Pollutants Acute WET Toxicity Monitoring Phosphorus Additional Requirements Special Requirement Land Application of Industrial By-Products Salty Discharge Compliance Schedule Nitrogen Monitoring Biosolids Total Facility Requirements Nondegradation and Anti-Backsliding

3 Purpose and Participation Applicable Statutes This fact sheet has been prepared according to 40 CFR and and Minn R , subp. 3, in regards to a draft National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) Permit (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; and 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 and Minn. R , your petition requesting a public informational meeting must identify the matter of concern and must include items 1 through 3 identified above and 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 the reasons or proposed findings supporting the MPCA decision to hold a contested case hearing pursuant to the criteria identified in Minn. R , 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 1 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. During the public comment period, however, you may request that the draft Permit be presented to the MPCA s Citizens Board (Board) for final decision. You may participate in the activities of the Board as provided in Minn. R

4 Comments, petitions, and/or requests must be submitted by the last day of the public comment period to: Ashley Wahl Minnesota Pollution Control Agency 504 Fairgrounds Road, Suite 200 Marshall, Minnesota The Permit will be reissued if the MPCA determines that the proposed Permittee 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 Facility and Outfall Location The Willmar (City) Wastewater Treatment Facility (Facility) is located in the SE¼ of Section 23, Township 119 North, Range 36 West, St. Johns Township, Kandiyohi County, Minnesota. The Facility has a continuous discharge with one outfall (SD005). The location of the Facility and SD005 are shown in Figure 1. 4

5 Figure 1. Location of Permitted Facility and Discharge Station 5

6 Components and Treatment Technology Current Information The newly constructed Facility initiated operation in September 2010, is designed to treat and average wet weather design flow (AWWDF) of 7.52 million gallons per day (mgd), and consists of a new 48-inch interceptor conveying domestic flow from the original plant site to the new Facility, and a forcemain conveying industrial flow from the Jennie-O Turkey Store. The domestic wastewater treatment components include screw pumps, mechanical screening, grit removal, a selector basin, two oxidation ditches, two final clarifiers and ultraviolet disinfection. The industrial treatment components include a selector basin, two oxidation ditches, one final clarifier, and ultraviolet disinfection. Effluent from the two treatment components combine prior to disinfection. The Facility also adds ferric chloride for phosphorus removal. The industrial and municipal solids are handled separately. The Facility has one gravity belt thickener for each treatment train, a total of three above ground storage tanks, and one below ground storage tank. Solids are land applied based on categorization of biosolids or industrial by-product. This is a Class A facility. Plans and specifications by Donohue & Associates dated June 9, 2008, are on file with the MPCA. Changes to Facility or Operation There are no proposed changes to the Facility at this time. 6

7 Flow Schematic Figure 2. Flow Schematic 7

8 Significant Industrial Users The Facility accepts wastewater from three Significant Industrial Users (SIUs). Jennie-O Turkey Store, a turkey processing facility, sends approximately mgd of process flow water to the Facility. Rice Memorial Hospital sends the Facility approximately 47,000 gallons per day (gpd) of process wastewater and Willmar Municipal Utilities sends the Facility approximately 57,000 gpd of process wastewater used in the production of power. All SIUs are subject to local limits as defined in a user agreement between the Facility and the individual SIUs. Recent Compliance History A Compliance Evaluation Inspection (CEI) was conducted on January 27, 2015, by the MPCA to determine the Facility s compliance with the terms and conditions of its NPDES/SDS Permit. The following is a summary of the findings and comments resulting from that inspection. The CEI consisted of a visual inspection of the Facility and a discussion with Wastewater Superintendent Operator. In addition, there was a review of the monthly Discharge Monitoring Reports (DMRs) for the time period from January 2012 to December The Facility s biosolids land application sites were not inspected. Based on the results of the CEI, violations of the terms and conditions set forth in the NPDES/SDS Permit were noted. The alleged violations and recommended corrective actions are as follows: 8

9 9

10 Recent Monitoring History Table 1: Discharge Monitoring Report Results January 2014 Through December

11 Receiving Water Use Classification The Facility has a continuous discharge, SD005, to Hawk Creek. The water is classified as a 7, 3C, 4A, 4B, 5, 6 Water. The quality of Class 7 waters of the state shall be such as to protect aesthetic qualities, secondary body contact use, and groundwater for use as a potable water supply. More information on the classification of waters can be found in Minn. R Impairments Table 2. Impairments of the Receiving Waters AUID or Lake ID # AUID description or Lake name Assessment Category & subcategory Hawk Creek from north boundry 4A of Sect. 19, T119N, R35W to the south boundry of Sect. 31, T118N, R37W Pollutants or Impairment Mercury in fish tissue 11

12 Existing Permit Effluent Limits The limits and monitoring requirements in the current Permit are presented in Tables 3 and 4. These tables list state discharge restrictions and both water quality and technology-based limits. Table 3. Existing Effluent Limits for SD005 (continued on page 13). 12

13 Table 4. Existing Effluent Limits for SD005 (Continued from page 12). State Discharge Restrictions (SDRs) The limit for fecal coliform has been developed to meet state discharge restrictions specified under Minn. R Technology Based Effluent Limits (TBELs) The TSS, and ph are technology-based limits developed for achieving secondary treatment standards. These limits are specified in 40 CFR and in Minn. R Water Quality Based Effluent Limits (WQBELs) The ammonia-nitrogen, five-day carbonaceous biochemical oxygen demand (CBOD 5 ), dissolved oxygen and phosphorus limits are WQBELs. These effluent limits are based on the designated use classification of the receiving water. Water quality based limits are the limits which were determined to be necessary to protect the use classification for the receiving water. 13

14 Proposed Permit Effluent Limits The limits and monitoring requirements for the draft reissued Permit are presented in Tables 5 and 6. These tables list state discharge restrictions, and both water quality and technology-based effluent limits. Table 5. Proposed Effluent Limits and Monitoring for SD005 (continued on page 15) 14

15 Table 6. Proposed Effluent Limits and Monitoring for SD005 (continued from page 14) State Discharge Restrictions (SDRs) The limit for fecal coliform has been developed to meet state discharge restrictions specified under Minn. R Technology Based Effluent Limits (TBELs) The ph limit is a technology-based limit developed for achieving secondary treatment standards. These limits are specified in 40 CFR and in Minn. R Water Quality Based Effluent Limits The ammonia-nitrogen, five-day CBOD 5, dissolved oxygen TSS, and phosphorus limits are WQBELs. These effluent limits are based on the designated use classification of the receiving water. Water quality based limits are the limits which were determined to be necessary to protect the use classification for the receiving water.the bicarbonate, hardness, chloride, TDS and specific conductance limits are interim 15

16 limits. These limits were developed to ensure that the concentrations of these parameters do not increase during the time that is needed to attain compliance with the final WQBELs for these parameters. Priority Pollutant and Whole Effluent Toxicity (WET) Testing During the past permit cycle the Facility expanded and the upgraded facility became operational in August This Facility submitted three priority pollutant scans during the last permit cycle, but only one of the priority pollutant scans was done after August Reasonable Potential for Chemical Specific Pollutants (40CFR122.44(d)(1)) Reasonable Potential is a procedure specified by the U.S. Environmental Protection Agency (EPA) regulation that compares preliminary WQBELs for a pollutant with effluent monitoring data to determine the need for an effluent limitation. Federal regulations at 40 CFR (d)(1) require that pollutants be evaluated for the potential to exceed WQS ( Reasonable Potential ) using acceptable technical procedures, accounting for variability in the effluent. The Class 7 designation applies and aquatic life protections extends only to acute toxicity for pollutants other than bioaccumulative pollutants. Three or more samples are needed to complete a Reasonable Potential (RP) analysis. Since only one of the three priority pollutant scans required by the current permit was completed after the Facility upgrade, a RP analysis for tetrachloroethane, bis (2-ethylhexyl) phalate, beryllium, cadmium, lead, nickel, antimony, and thallium could not be completed, but information on the sample collected after the Facility upgrade is summarized below. The concentrations of tetrachloroethane and bis (2-ethylhexyl) phalate were 7.9 micrograms per liter (µg/l) and 8.9 µg/l, respectively. This tetrachloroethane concentration is about 250 times smaller than the FAV therefore, this organic pollutant is of no concern. A value of bis (2-ethylhexyl) phalate smaller than 10 µg/l is usually an indication that the sample was contaminated with plastic in the laboratory. The rest of the organic priority pollutants were all less than detectable levels. The metals beryllium, cadmium, lead, nickel, antimony, and thallium were all below levels of detection. The salty parameters were monitored during the current permit cycle and a RP analysis was completed. Minn. R subp. 6 lists the water quality standards for the class 3C, industrial use (250 mg/l for chloride, and 500 mg/l for hardness (Ca + Mg as CaCO 3 )) and for class 4A, agricultural irrigation use (5 milliequivalents per liter (meq/l) for bicarbonate; 1000 micromhos per centimeter (µmhos/cm) for specific conductance and 700 mg/l total dissolved solids). To perform the RP analysis of parameters it is necessary to know the receiving water quality upstream of the discharge for those parameters. Few data values for chloride, specific conductance, and copper were found. The measurements were done in 1979 and in 1984 in Hawk Creek at MN-40 1 mi Southwest of Willmar (S ). The Facility does WET tests and these tests are preformed, the Facility samples the receiving water for total hardness and total alkalinity and measures specific conductance upstream of the outfall. In 1997 and in 1998, the Facility also measured bicarbonates (HCO 3 ) in the receiving water. This information was used in the analysis. A regression analysis between the specific conductance of the effluent and that of the receiving water upstream of the discharge was done with the data provided with the WET test. The 16

17 relationship between both parameters is linear (R 2 =0.9). A regression analysis was done with the specific conductance data and TDS data measured in the current permit cycle. This relationship is also linear (R 2 =0.8). There were no measured TDS values in the receiving water, however, based on the fact that the correlation between the specific conductance in the effluent and receiving water is strong and so it is between the specific conductance and TDS in the effluent, it is expected that the TDS and the specific conductance of the receiving water will be strong and will follow a similar linear trend. The information on HCO 3, hardness and specific conductance in the receiving water upstream of the outfall and the statistical analysis of TDS indicate that these parameters are at least at the water quality standard therefore the water quality standards were used as the background or receiving water quality parameter values. Table 7 contains the RP analysis and the limits for those variables that showed RP to exceed or contribute to an exceedance of the water quality standards. The analysis was done for copper (Cu), selenium (Se), mercury (Hg), HCO 3, chloride (Cl - ), hardness, total dissolved salts (TDS) and specific conductance. The percent of sodium (Na + ), compared to the sum of sodium (Na + ), potassium (K + ), calcium (Ca 2+ ) and magnesium (Mg 2+ ), is smaller (54%) than 60% and no RP is indicated. The Facility should have monitored silver using EPA methods or or a revision of these methods, however that was not done and the level of detection of the method that was used is higher than the water quality standards for silver, therefore this parameter could not be evaluated. 17

18 Table 7. Inputs to the Reasonable Potential Analysis Parameter Cu Se Hg HCO3- Cl- Hardness TDS Spec Cond (ug/l) (ug/l) (ng/l) (meq/l) (mg/l) (mg/l) (mg/l) (umhos/cm) Max measured value # data points PEQ Facility ADW Flow (mgd) Rec. water flow, 7Q10(mgd) Background Concentration Continuous Standard (cs) ppm hardness Maximum Std (ms) NA NA NA NA NA 400 ` ppm hardness Final Acute Value (FAV) NA NA NA NA NA 400 ppm hardness Mass Balance -cs Mass Balance -ms NA NA NA NA NA Coeff of Variation (CV) Long Term Avg-cs Long Term Avg-ms NA NA NA NA NA Preliminary Effluent limits: Daily Max Monthly Ave (2x/month) Reasonable Potential PEQ>Daily max NA NA FALSE TRUE TRUE TRUE TRUE TRUE PEQ> FAV FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE PEQ >Mo. Av NA NA FALSE TRUE TRUE TRUE TRUE TRUE Final Reasonable Potential No No No Yes Yes Yes Yes Yes * Mercury background assumed to be at the standard because of Hawk Creek Fish Consumption Advisory. Other metals compared to FAV only for Class 7 waters. The Facility may discontinue the quarterly monitoring of copper and selenium. The Facility needs to monitor silver quarterly using EPA Inorganic Analytical Methods (EPA 600/ ) or (method detection level <0.2 µg/l) or revisions to those methods. Salty Parameters Interim and Final Limits and Monitoring The Facility has indicated its inability to comply with the daily maximum and the average monthly limits at this time and requested interim salty limits. The interim limits included herein are designed to assure that the salty parameters in the discharge do not increase while the interim limits are in effect. The interim daily maximum limits were computed as the largest of the projected effluent quality (PEQ) or the value that corresponds to the 95 th percentile of the lognormal distribution. 18

19 Table 8: Interim limits based on levels currently achievable for data in the years Parameter Interim limit Daily max. interim limit Hardness (CaCO3) (mg/l) Specific Conductance micromhos per centimeter (µmhos/cm) Bicarbonates (HCO 3 ) Chloride (mg/l) TDS (mg/l) 7.95 milliequivalents per liter (meq/l); 485 milligrams per liter (mg/l) Table 9: Final daily maximum and average monthly effluent concentration/parameter limits Parameter Final Limit Daily max Monthly avg. (2x/month) Bicarbonates (HCO 3 ) Chloride (mg/l) Hardness (CaCO3) (mg/l) TDS (mg/l) 6 meq/l; 378 mg/l Specific Conductance (µmhos/cm) 5 meq/l; 331 mg/l Because of the monthly limits, the Facility needs to monitor twice per month. Data taken quarterly, twice in the same month each quarter during the life of the permit is sufficient to do an analysis of the evolution of these parameters over time. The cations Na +, Ca 2+, Mg 2+, and K + are measured to determine the ratio Na + to the sum of cations. In this permit cycle, Na + was 54% of the cations, getting close to the 60%, therefore the Facility needs to monitor these cations twice per year. Sulfate: the data submitted during this permit cycle provide sufficient information at the present time therefore sulfate sampling can be discontinued. Permit Limitations for Mercury Effluent data for the existing Facility indicates that the discharge has no RP to cause or contribute to an exceedance of the mercury water quality standard. No limit is needed. Twice per year monitoring of dissolved and total mercury and TSS (grab) in their effluent and submission of a MMP before the NPDES Permit expires. 19

20 Reasonable Potential for WET No acute toxicity has been indicated in the three acute tests provided for this cycle. No RP to exceed acute toxicity for WET and no limit is needed. Acute WET Testing The Facility will be required to conduct annual acute toxicity test batteries on Discharge SD005 beginning with beginning with the first full calendar year quarter following the issuance date of the Permit and annually thereafter. Phosphorus Background Currently, the Facility has an average wet weather design flow (AWWDF) of 7.51 mgd and a 1.0 mg/l total phosphorus (TP) limit and discharges to a class 7 ditch upstream of Hawk Creek. River eutrophication standards (RES) have recently been approved by EPA. Previous TP effluent limit reviews did not consider RES. This following will summarize pertinent information from memorandums regarding Lake Pepin and the Minnesota River, and it covers some new analysis regarding Hawk Creek. Hawk Creek Hawk Creek is a tributary to the Minnesota River Yellow Medicine Watershed. The TP concentration of Hawk Creek was historically elevated due to the Facility (Appendix A, Table 1). Implementation of TP removal at the Facility has resulted dramatic reduction of TP concentration in Hawk Creek during the 80% exceeds summer flow (Appendix B). Table 10. Annual load of total phosphorus discharged by Willmar WWTP from Year Load (kg/yr) , , , , , , , , , ,270 Suspended algae tend to grow well in rivers larger than Hawk Creek. Chlorophyll-a samples have not been collected from Hawk Creek. Koschak et al. (2013) found no biological impairments or dissolved oxygen issues in Hawk Creek. Despite historically high concentrations of TP, Hawk Creek does not exhibit local eutrophication problems (Appendix C). The TP in Hawk Creek does contribute to downstream eutrophication impairments discussed in the following sections. Minnesota River (RES) Willmar is one of the collective facilities in the Minnesota River Basin that contribute phosphorus to the Minnesota River (Wasley, 2015). Several reaches of the Minnesota River, including reaches of the Minnesota River downstream of Hawk Creek, exceed the recently adopted River eutrophication standards (RES) (Appendix D). Based on HSPF modeling, the WQBEL for Minnesota River is a monthly 20

21 average mass limit of 22.1 kg/day. This limit only applies from June to September. These limits will apply from June-September as a monthly average and are based on meeting RES throughout the mainstem of the Minnesota River downstream of Lac qui Parle Dam. Minnesota River Yellow Medicine Watershed: Minnesota River at Morton (excerpt from Wasley, 2015) The Minnesota River Yellow Medicine Watershed is the next upstream watershed of the Minnesota River - Mankato Watershed. Concentration at a representative site near the outlet of the watershed in Morton indicates that TP is above the RES at the critical 80 % exceeds flow (Figure 3). This Morton station is approximately 9 miles downstream of the farthest upstream reach of the Minnesota River mainstem exceeding both the cause and response variables of RES. There are no readily available HSPF data for the Minnesota River at Morton. A RP equation was constructed to determine if limits based on HSPF model results for the Minnesota River at two downstream watersheds were sufficient to protect Minnesota River at Morton. Figure 3. Monitored daily summer (June-September) total phosphorus load of the Minnesota River at Morton (station S ) from Percent exceeds flow based on summer flows (Minnesota River at Morton). Concentration at critical flow = mg/l (n=7). Blue line represents load at RES (0.150 mg/l). Flow (% exceeds) x100 The following equation was used to calculate the RP of the continuously discharging facilities (at the WLA for the middle and lower Minnesota River) upstream of Morton to cause or contribute to a nutrient impairment in the Minnesota River (Equation 1). Equation 1. TP concentration of Minnesota River at Morton based on permitted flow for upstream facilities. Cr = QsCs + QeCe Qr 21

22 Cr = downstream TP concentration of river at critical flow (80 percent exceeds flow) Qr = downstream river flow (80 percent exceeds flow) Qs = flow of river without WWTFs Cs = concentration of river without WWTFs Qe = design flow of WWTFs Ce = long term effluent concentration, existing concentration limit or concentration target of mass limit Qr = 292 mgd; based on permitted flow values and using Qr = Qs + Qe Qs = 275 mgd; calculated using average daily flow from USGS gauge at the outlet of the watershed during June September at 80 percent exceeds flow and subtracting upstream WWTFs average daily flow during June September, Cs = mg/l; concentration for the Minnesota River at Morton at 80 percent exceeds flow without WWTFs Qe = 17.9 mgd; 70% of permitted AWWDF for municipals and 100% of MDF for industrials Ce = 0.65 mg/l; flow-weighted concentration WLA from downstream HSPF stations Cr = mg/l TP Cr sen = mg/l TP (sensitivity run) Because the calculated Cr of mg/l is less than the RES of mg/l, it was determined that the limits needed for downstream reaches of the Minnesota River are protective of the Minnesota River at Morton. Given that this station is the farthest upstream station in the Minnesota River Basin exceeding RES and has 31% of continuous WWTFs by design flow, it is logical to conclude that this river reach would have the greatest potential increase in projected river concentration if summer mass limits were applied instead of concentration limits. The collective mass from the treatment plants (WLA = 44.0 kg/day) was frozen while the collective WWTF flows were reduced from 17.9 to 11.6 mgd. The maximum increase in the concentration of the river from mass only limits would result in an increase from to mg/l during critical low flow conditions. This slight potential shift would not result in a significant change in algal abundance in the Minnesota River at Morton. Thus, only monthly mass limits will be required during summer for RES in the Minnesota River. The Lower Minnesota River (low dissolved oxygen) A Total Maximum Daily Load (TMDL) study was completed for the Lower Minnesota River. The Minnesota River Basin General Phosphorus Permit (Basin Permit) was subsequently developed to implement wasteload allocations (WLA) during the TMDL-specified May through September window of concern. The City has a seasonal WLA listed in Appendix B of the Basin Permit. Although Phase I of the Basin Permit has expired, the limits remain applicable. Lake Pepin Weiss (2013) determined that Willmar has RP to cause or contribute to the excess nutrient impairment in Lake Pepin and is therefore required to have a WQBEL. The WQBEL for Lake Pepin is 8,300 kg/yr. 22

23 Summary Table 11 summarizes the various TP limits for the Facility. Table 11. Summary of TP effluent limits for Willmar WWTP. Waterbody Limit Season Limit type Basis Minnesota River 22.1 kg/day Jun Sept Calendar month average WQBEL (RES) Hawk Creek 1.0 mg/l Jan - Dec Calendar month average State discharge restriction Minnesota River (low DO)* 7,332 kg/season May Sept Season total TMDL Lake Pepin 8,300 kg/yr Jan-Dec 12 month moving total WQBEL *Limit included in overlay permit: Minnesota River Basin General Phosphorus Permit Phase I Additional Requirements Special Requirements-Land Application of Industrial by-products: This Permit allows the Permittee the option to land apply industrial by-products. Should the Permittee decide to do this, the following submittals will be required: Plan for Sampling, Analysis, and Field Equipment Calibration: Ninety (90) days prior to the initial land application of any Industrial By-Products, the Permittee must submit a sampling, analysis and field equipment calibration plan. Industrial By-Product Annual Report: An Industrial By-Product Land Application Annual Report is due by January 31 st of each year following the first Industrial By-Product land application and annually thereafter. Salty Discharge Compliance Schedule: Chapter 1 of the Permit contains a schedule to attain compliance with the final WQBELs as soon as possible, but no later than April 30, 2035 (20 years after projected permit issuance.) Nitrogen Monitoring: Nitrogen is a pollutant that can negatively impact the quality of Minnesota s water resources, including water used for drinking. Studies have shown that nitrogen in lakes and streams has a toxic effect on aquatic life such as fish. Like phosphorus, nitrogen is a nutrient that promotes algae and aquatic plant growth often resulting in decreased water clarity and oxygen levels. In 2013 the MPCA completed a draft Statewide Nutrient Reduction Strategy ( which identifies goals and milestones for nitrogen reductions for both point and non-point nitrogen sources within Minnesota. To gain a better understanding of the current nitrogen concentrations and loadings received by and discharged from your Facility additional influent and effluent nitrogen monitoring has been added to the Permit. This monitoring has been added in accordance with Minn. Stat. ch The Permit requires additional influent and effluent monitoring for Nitrite plus Nitrate-Nitrogen and Total Kjeldahl at a frequency of once per month for the five-year term of the Permit. 23

24 Biosolids This draft reissued Permit authorizes the City to store and land apply domestic wastewater treatment biosolids in accordance with the provisions of Chapter 9 of this draft Permit and Minn. R. ch Total Facility Requirements (TFR) All NPDES 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 These conditions are listed in the Total Facility Requirements chapter of an NPDES 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 reissuance. Nondegradation and Anti-Backsliding In accordance with the MPCA s rules regarding nondegradation for all waters that are not ORVW, nondegradation review is required for any new or expanded significant discharge (Minn. R ). A significant discharge is: 1. A new discharge (not in existence before January 1, 1988) that is greater than 200,000 gpd to any water other than a Class 7 water; 2. An expanded discharge that expands by greater than 200,000 gpd that discharges to any water other than a Class 7 water; or 3. A new or expanded discharge containing any toxic pollutant at a mass loading rate likely to increase the concentration of the toxicant in the receiving water by greater than 1% over the baseline quality. The flow rate used to determine significance is the AWWDF. The January 1, 1988, AWWDF for this Facility is 5.04 mgd. This Permit also complies with Minn. R , regarding anti-backsliding. Any point source discharger of sewage, industrial, or other wastes for which an NPDES Permit has been issued by the Agency that contains effluent limits more stringent than those that would be established by Minn. R to , 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) (2) (A) of the Clean Water Act, United States Code, title 33, section