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

Transcription

1 National Pollutant Discharge Elimination System / State Disposal System (NPDES/SDS) Permit Program Fact Sheet Permittee: City of Zumbrota Facility Name: Zumbrota WWTF Permit Number: MN West Avenue 309 East Street Zumbrota, MN Zumbrota, MN Current Permit Expiration: September 30, 2013 Public Comment Period Begins: February 14, 2014 Period Ends: March 17, 2014 Receiving Water: North Fork Zumbro River (Class 2B, 3C, 4A, 4B, 5,6 Waters) Proposed Action: Permit Reissuance Permitting Contact Melanie Miland Minnesota Pollution Control Agency Municipal Division 18 Wood Lake Drive Southeast Rochester, MN Office: Fax:

2 Table of Contents Purpose and Participation... 3 Fact Sheet Purpose... 3 Applicable Statutes... 3 Public Participation... 3 Facility Description... 4 Background Information... 4 Facility Location... 4 Outfall Location... 4 Map of Permitted Facility... 5 Components and Treatment Technology... 6 Current Information... 6 Flow Schematic... 6 Changes to Facility or Operation... 7 Significant Industrial Users... 7 Recent Compliance History... 7 Recent Monitoring History... 7 Receiving Water... 8 Use Classification... 8 Impairments, Listings, and Total Maximum Daily Load Studies... 8 Existing Permit Effluent Limits... 9 Technology Based Effluent Limits... 9 Water Quality Based Effluent Limits... 9 Proposed Permit Effluent Limits State Discharge Restriction Limits Technology Based Effluent Limits Water Quality Based Effluent Limits Additional Requirements Pollutant Minimization Plans Additional Nitrogen Monitoring Biosolids Compliance Schedules Variances Total Facility Requirements Nondegredation and Anti backsliding

3 Purpose and Participation Applicable Statutes This fact sheet has been prepared according to the Title 40 CFR and and Minn R , 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 and Minn. R , 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 s 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: Melanie Miland Minnesota Pollution Control Agency 18 Wood Lake Drive Southeast Rochester, MN The permit will be issued/reissued/modified 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 Facility Location The Zumbrota Wastewater Treatment Facility (Facility) is located in the SE ¼ of the SW ¼ of Section 30, Township 110 North, Range 15 West, one half mile north of Zumbrota on East Street and north of the Zumbro River off of Highway 58. Outfall Location The Facility has a continuous discharge with one outfall (SD002). The outfall is located next to the Facility, as described above. The location of the Facility and SD002 are shown in Figure 1. 4

5 Map of Permitted Facility Figure 1. Location of Permitted Facility and Discharge Station MN : Zumbrota Wastewater Treatment Facility T 110 N, R 15W, Section 30 City of Zumbrota, Goodhue County, Minnesota 5

6 Components and Treatment Technology Current Information Major components of the Facility include: 1 Bar Screen mechanical 1 Bar Screen manual 1 Grit Removal 2 Primary Clarifier 1 Trickling Filter 1 Intermediate Clarifier 2 Rotating Biological Surfaces 2 Secondary Clarifier 1 Chlorination 1 Dechlorination 2 Anaerobic Digester complete mixed, heated mesophilic 4 Aerated Polishing Ponds less than 180 days detention time (5.5 acres total) 1 Storage Tank The Facility has a continuous discharge to the north fork of the Zumbro River and is designed to treat an average wet weather (AWW) flow of 1.11 million gallons per day (mgd) and an average annual flow of mgd with a five day biochemical oxygen demand (CBOD 5 ) strength of 565 milligrams per liter (mg/l) and a total suspended solids (TSS) strength of 279 mg/l based on average annual flow. This is a Class B facility. The Facility is further described in a facilities plan by the firm of Howard A. Kuusisto, St. Paul, Minnesota; in plans and specifications by the firm of Bonestroo, Rosene, Anderlik and Associates Incorporated, St. Paul, Minnesota, approved by the MPCA on June 30, 1983; and on file with the MPCA. Flow Schematic 6

7 Changes to Facility or Operation According to the permit application submitted on May 15, 2013, proposed repair and replacement of a new boiler heat exchanger and digester cover shall occur during the upcoming permit cycle. Significant Industrial Users (SIUs) The Facility is currently accepting wastewater from one SIU, Dairy Farmers of America (DFA) in Zumbrota, Minnesota. Principal product is dairy with milk being the raw material. Dairy Farmers of America sends an average of 338,000 gallons per day (gpd) of processed wastewater continuously to the Facility for treatment and is subject to local limits. Recent Compliance History Violations were discovered during a Compliance Evaluation Inspection (CEI) of the Facility on June 28, 2012, by the MPCA staff, as described in the Letter of Warning dated October 10, The CEI consisted of a visual inspection of the facility and a discussion with Facility staff. In addition, there was a review of the monthly Discharge Monitoring Reports (DMRs) for the time period from July 1, 2010 to June 27, A Biosolids Compliance Inspection was also conducted as part of the inspection. Based on the results of the CEI, 16 violations of effluent limits set forth in the NPDES/SDS Permit were noted and investigated. No additional corrective actions were associated with these violations and the case was closed. Recent Monitoring History Table 1. Discharge Monitoring Report Results November 2012 Through October

8 Receiving Water(s) Use Classification The receiving water is a Class 2B, 3C, 4A, 4B, 5, 6 water. This classification indicates that the body of water is capable of sustaining the propagation and maintenance of a healthy community of indigenous fish and associated aquatic life, and their habitats. The classification also indicates that these waters shall be suitable for boating and other forms of aquatic recreation for which the waters may be usable. 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 North Fork Zumbro River (Headwaters to Trout Brook) Zumbro River (North Fork Zumbro River to Cold Creek) Assessment Category & Subcategory 5C 5B Pollutants or Impairment Turbidity Mercury, PCBs Fecal Coliform: These impairments are addressed in the Lower Mississippi River Basin Regional Fecal Coliform Total Maximum Daily Load (TMDL). This TMDL was approved by U.S. Environmental Protection Agency (EPA) on April 5, A Waste Load Allocation (WLA) is assigned to the Facility s discharge. Mercury: This water is on the 303(d) list as impaired for mercury. There is a completed TMDL for mercury, referred to as the Statewide Mercury TMDL Pollutant Reduction Plan, The statewide mercury TMDL was approved by EPA on March 27, Additional information on the requirements for controlling mercury for major municipal permits is provided in the Additional Requirements section below. The Statewide Mercury TMDL is applicable to this impairment. Permit limits and monitoring requirements should be in accordance with the Mercury Permitting Strategy. Polychlorinated Biphenyl (PCB): There are a number of PCB impairments that were not specifically outlined in this review. The TMDLs are not underway for PCB impairments at this time. Turbidity: This impairment is addressed in the Zumbro River Watershed Turbidity TMDL. This TMDL was approved by EPA on May 25, A WLA was assigned to the Facility s discharge. 8

9 Existing Permit Effluent Limits The limits and monitoring requirements in the current permit are presented in Table 3. This table lists both water quality and technology based limits. Table 3. Existing Discharge Limits for Station SD006 Technology Based Effluent Limits (TBELs) The CBOD 5, fecal coliform bacteria, potential of Hydrogen (ph), TSS, and percent removal limits 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 Total Residual Chlorine (TRC) limit is the final acute value for chlorine found in Minn. R This limit is determined to be necessary to protect the use classification of the receiving water. 9

10 Proposed Permit Effluent Limits The limits and monitoring requirements for the draft reissued Permit are presented in Table 4. This table lists state discharge restrictions, water quality and technology based effluent limits. Table 4. Proposed Effluent Limits for Station SD006 10

11 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 The CBOD 5, 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 Limits The TRC limit is the final acute value for chlorine found in Minn. R This limit is determined to be necessary to protect the use classification of the receiving water. Background The discharge is located on the North Fork of the Zumbro River. The discharger has submitted six Whole Effluent Toxicity tests and two priority pollutant scans since December The discharger has a.807 mgd Average Annual design flow and AWW of 1.11 mgd. The AWW was used to calculate water qualitybased effluent limits under critical low flow stream conditions. The low flow condition is defined by the once in 10 year weekly average flow (7Q 10 ), which is determined to be 12.9 mgd at the discharge location. The AWW design flow is used for nondegradation evaluations applicable in Minnesota R The dilution ratio is 7.5:1, river low flow to effluent flow at the AWW. The analysis below is based on data submitted to date. Reasonable Potential for Chemical Specific Pollutants (40CFR122.44(d)(1)) Federal regulations require the MPCA to evaluate the discharge to determine whether the discharge has the reasonable potential to cause or contribute to a violation of water quality standards. The MPCA 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 evaluated using reasonable potential procedures. All of the organic priority pollutants were below the level of detection. Since these pollutants were at low enough levels not to be detected, reasonable potential to cause or contribute to a water quality standards excursion is not indicated. Therefore no limit is needed in either case. From the table below Selenium, Zinc and Arsenic indicated no reasonable potential to cause or contribute to an excursion above the applicable water quality standard. No effluent limits are needed. Mercury monitoring results of the effluent included 12 data points at a calculated CV of During this time there was high variability in the sample results. However, starting in 2011 and progressing into early 2012, work was done at the Facility to replace internal components of the treatment works. This work has reduced the variability that the Facility has been reporting. For this reason, only the last five data points were used as was the default CV of.6. PEQ was derived as an upper bound value from the highest value measured (3.6 nanograms per liter (ng/l)), and the determined variability (CV =.6) and number of data points (5). The PEL calculation assumes that the background mercury concentration is at the water quality standard (6.9 ng/l) when the listed stream impairment is for fish consumption advice, 11

12 and no local river water column analytical data exist. To assure that the discharge does not cause or contribute to a water quality standards excursion for mercury impaired waters, the numeric water quality standard (6.9) is applied at the point of discharge for the mass balance equation for the subsequent preliminary effluent limit calculations. Where PEQ exceeds the PEL, there is reasonable potential to cause or contribute to a water quality standards excursion. Since PEQ does not exceed the PEL in this case, reasonable potential to cause or contribute to an excursion above water quality standards is not indicated. A WQBEL is not needed. Continued monitoring is required as listed in 2013 Permitting Strategy for Addressing Mercury in Municipal and Industrial Wastewater Permits. Table 5 contains the inputs to the reasonable potential analysis for copper (Cu), selenium (Se), zinc (Zn), arsenic (As), and mercury (Hg). The analysis is made with effluent data that are expressed as total metal. These pollutants were evaluated on the basis of analytical measurements that made evident the need for a full determination. Where PEQs exceed PELs, a WQBEL is needed. Table 5. Proposed Water Quality Based Effluent Limit Calculations PARAMETER CU (ug/l) SE (ug/l) ZN (ug/l) AS (ug/l) HG (ng/l) Maximum measured effluent value Projected effluent quality n data points 30 (2) 4.03 (2) 190 (2) (2) 8 (5) Plant design flow (mgd) Receiving water design flow (mgd) Background concentration * Continuous standard Hd Maximum standard Hd Final acute value Hd Mass Balance cs Mass Balance ms Coefficient Of Variation (CV) Long Term Average: LTA cs LTAms Preliminary Effluent Limit (PEL): Daily Maximum Monthly Average Reasonable Potential PEQ>PEL (Dmax/FAV) Yes No No No No *Mercury background assumed to be at the standard because of the statewide mercury TMDL. 12

13 Reasonable Potential Conclusions for Copper Reasonable potential to cause or contribute to the excursion above a water quality standard has been indicated for copper, based conservatively on the use of two total metal monitoring data points. In lieu of copper limits, it is recommended that the discharger monitor total and dissolved copper in the effluent two times per year for life of the permit to build a larger database and provide information on the ratio of total to dissolved copper. This will reduce the conservatism in the calculation and provide a clearer basis for evaluating any exceedence of the copper water quality standard based on total and dissolved metal monitoring. The following EPA Inorganic Analytical Methods (EPA 600/ ) and EPA Organic Analytical Methods (40 CFR 136; October 26, 1984) apply: Pollutant Monitoring Frequency EPA Method Method Detection Level Copper, Two times per year; Total life of permit Copper, Dissolved Two times per year; life of permit Additional Requirements Mercury Minimization Plan (MMP): The Limits and Monitoring section of this draft Permit contains requirements for effluent mercury monitoring and an updated MMP submitted on March 27, These requirements were added in response to the EPA s approval of the Minnesota statewide mercury TMDL plan. In addition to the sampling required in the Limits and Monitoring section of this draft Permit, the City is required to sample effluent two times per year for dissolved mercury with a concurrent TSS grab sample. The data will be recorded on a custom supplemental form provided by the MPCA and must be submitted with the DMR. The specific language regarding this additional sampling is located in Chapter 4, Surface Discharge Stations, of this draft reissued Permit. Phosphorus Management Plan (PMP): The city submitted a PMP on March 27, The proposed permit requires the city to update the PMP and submit the updated plan to the MPCA 180 days prior to permit expiration. The PMP requirements include identifying possible sources of influent phosphorus and investigating possible changes in the treatment process that would result in reduced effluent phosphorus. Additional Nitrogen Monitoring The draft permit requires additional monitoring for Nitrite plus Nitrate Nitrogen, Total Dissolved Solids, and Total Kjeldahl at a frequency of two times per year for the five year term of the permit. This monitoring is being added to all reissued NPDES/SDS permitted municipal facilities that have an AWW design flow of 100,000 gpd or greater. Biosolids This draft reissued permit authorizes the city to store and land apply domestic wastewater treatment biosolids in accordance with the provisions of chapter 8 of this draft permit and Minn. R. ch

14 Compliance Schedules The Facility is currently in compliance with its current NPDES/SDS Permit. This draft reissued permit does not contain any compliance schedules since none are needed at this time. Variances Not applicable. Total Facility Requirements 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 Title 40 CFR These conditions are listed in the Total Facility Requirements chapter of an 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 reissuance. Nondegradation and Anti Backsliding In accordance with the MPCA rules regarding nondegradation for all waters (that are not Outstanding Resource Value Waters (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 or 2) an expanded discharge that expands by greater than 200,000 gpd that discharges to any non ORVW 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 one percent over the baseline quality. The flow rate used to determine significance is the design wet AWW flow. The January 1, 1988, design AWW flow for this Facility is 1.1 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/SDS Permit has been issued by the MPCA that contains effluent limits more stringent than those that would be established by parts 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) of the Clean Water Act, United States Code, title 33, section