Npdes Permit No
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NPDES PERMIT NO. NM0030848 FACT SHEET FOR THE DRAFT NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT TO DISCHARGE TO WATERS OF THE UNITED STATES APPLICANT City of Santa Fe Buckman Direct Diversion 341 Caja del Rio Road Santa Fe, NM 87506 ISSUING OFFICE U.S. Environmental Protection Agency Region 6 1201 Elm Street, Suite 500 Dallas, TX 75270 PREPARED BY Ruben Alayon-Gonzalez Environmental Engineer Permitting Section (WDPE) Water Division VOICE: 214-665-2718 EMAIL: alayon.gonzalez.ruben@epa.gov DATE PREPARED May 29, 2019 PERMIT ACTION Proposed reissuance of the current NPDES permit issued July 29, 2014, with an effective date of September 1, 2014, and an expiration date of August 31, 2019. RECEIVING WATER – BASIN Rio Grande Permit No. NM0030848 Fact Sheet Page 2 of 16 DOCUMENT ABBREVIATIONS In the document that follows, various abbreviations are used. They are as follows: 4Q3 Lowest four-day average flow rate expected to occur once every three years BAT Best available technology economically achievable BCT Best conventional pollutant control technology BPT Best practicable control technology currently available BMP Best management plan BOD Biochemical oxygen demand (five-day unless noted otherwise) BPJ Best professional judgment CBOD Carbonaceous biochemical oxygen demand (five-day unless noted otherwise) CD Critical dilution CFR Code of Federal Regulations Cfs Cubic feet per second COD Chemical oxygen demand COE United States Corp of Engineers CWA Clean Water Act DMR Discharge monitoring report ELG Effluent limitations guidelines EPA United States Environmental Protection Agency ESA Endangered Species Act FCB Fecal coliform bacteria F&WS United States Fish and Wildlife Service mg/L Milligrams per liter µg/L Micrograms per liter MGD million gallons per day NMAC New Mexico Administrative Code NMED New Mexico Environment Department NMIP New Mexico NPDES Permit Implementation Procedures NMWQS New Mexico State Standards for Interstate and Intrastate Surface Waters NPDES National Pollutant Discharge Elimination System MQL Minimum quantification level O&G Oil and grease PCB Polychlorinated Biphenyl POTW Publically owned treatment works RP Reasonable potential SIC Standard industrial classification s.u. Standard units (for parameter pH) SWQB Surface Water Quality Bureau TDS Total dissolved solids TMDL Total maximum daily load TRC Total residual chlorine TSS Total suspended solids UAA Use attainability analysis USGS United States Geological Service WLA Wasteload allocation WET Whole effluent toxicity WQCC New Mexico Water Quality Control Commission WQMP Water Quality Management Plan WWTP Wastewater treatment plant In this document, references to State WQS and/or rules shall collectively mean the State of New Mexico. Permit No. NM0030848 Fact Sheet Page 3 of 16 I. CHANGES FROM THE PREVIOUS PERMIT Changes from the permit previously issued July 29, 2014, with an effective date of September 1, 2014, and an expiration date of August 31, 2019, are: 1. No changes have been made to the previous permit. II. APPLICATION LOCATION and ACTIVITY As described in the application, the plant is located at 341 Caja del Rio Road, Santa Fe County, New Mexico. Under the SIC Code 4941, the applicant operates a Water Treatment Plant. This permitting action is specifically restricted to the discharge of materials back to the Rio Grande River by the Buckman Direct Diversion (BDD). The BDD project diverts water from the Rio Grande through a large intake structure to provide up to 15 MGD of drinking water to the City and County of Santa Fe. Diverted water is pumped from the river approximately 11 miles to the Buckman Regional Water Treatment Plant. Water intake operations occur at varying dates and times depending on variables such as river flow and upstream turbidity. The grit/sand removal at BDD is accomplished with the single pass liquid- solid separation system “LAKOS”. The LAKOS system is a patented design that uses centrifugal forces to separate sand and grit from the raw water pumped into the units. No chemicals are added prior or during the pre-treatment of the influent. The efficiency of this separator depends on the specific gravity of the suspended solids and their particle size, being less efficient for lighter and finer particles, and more efficient for heavier and larger particles. The sand (about Permit No. NM0030848 Fact Sheet Page 4 of 16 40% of total sediment) is returned to the Rio Grande, which is expected to increase the sediment concentrations (TSS) by less than 2%. The near-river diversion facilities consist of a raw water pump station and a co-located booster station and sediment removal facility. The concentrated sediment effluent generated from the gravity centrifuge process is collected in a sump which is then batch discharged utilizing additional dilution water from the river. The discharge occuring at Outfall 001 consists of sand-sized sediment removed from the diverted river water, return flow from the continuous samplers in the mechanical building, and water from the sumps in the raw water lift station. The BDD effluent returns residuals to the Rio Grande at an average of 0.2 MGD. III. RECEIVING STREAM STANDARDS The discharge is located at Latitude 35o 50’ 10” North, Longitude 106o 9’ 43” West. The discharge from the facility is to receiving waters named Rio Grande, in Waterbody Segment Code No. 20.6.4.114 of the Rio Grande Basin. The general and specific stream standards are provided in “New Mexico State Standards for Interstate and Intrastate Surface Waters”, (20.6.4 NMAC, effective August 11, 2017). The known uses of the receiving water(s) are irrigation, livestock watering, wildlife habitat, marginal coldwater aquatic life, primary contact, and warmwater aquatic life; and public water supply on the main stem of the Rio Grande. IV. EFFLUENT CHARACTERISTICS A quantitative description of the discharge(s) described in the EPA Permit Application Form 2C received February 12 and April 15, 2019 are presented below in Table 1: POLLUTANT TABLE – 1 Parameter Effluent Intake Max Daily Value Max 30 Day Long Term Avg Long Term Avg Value Value Value Conc. Mass Conc. Mass Conc. Mass Conc. Mass Flow, million 0.929 0.235 0.151 605 *** gallons/day (MGD) pH, minimum, 8.0 8.6 8.15 8.43 N/A N/A N/A N/A standard units (SU) min max min max Biochemical 13 0.007 T N/A N/A N/A N/A 13 mg/L 46 T Oxygen Demand mg/L (BOD5) * Chemical Oxygen 32 0.016 T N/A N/A N/A N/A 30 mg/L 106 T Demand (COD) * mg/L Total Organic 3.4 0.0017 T N/A N/A N/A N/A 3.6 mg/L 12.8 T Carbon * mg/L Total Suspended 320 0.161 T * N/A N/A 1,069 0.6 T 130 mg/L 461 T Solids (TSS) mg/L * mg/L ** ** *** *** Permit No. NM0030848 Fact Sheet Page 5 of 16 Parameter Effluent Intake Max Daily Value Max 30 Day Long Term Avg Long Term Avg Value Value Value Conc. Mass Conc. Mass Conc. Mass Conc. Mass Ammonia (as N) * <1 N/A N/A N/A N/A N/A <1 (ND) N/A (ND) Temperature, 12.5 12.5 7.5 7.8 winter (oC) Temperature, 25.4 22.8 19.3 19.6 summer (oC) * Samples were collected on Mar 25th, 2019 when effluent discharge was 0.133 MGD and Rio Grande daily flow was 937 MGD. ** Based on BDD NPDES Permit weekly TSS measurements from Jan 2011-Aug 2014. ***Based on measurement on Mar 25th, 2019. In comparison Otowi Gage data (7/1/17-6/30/18 when SSSC <900mg/l) showed Rio Grande intake had the following average values: SSC 360 mg/L, Flow 936 cfs, Mass 824 T. A summary of the last 36 months of available pollutant data from May 2016 through May 2019, taken from DMRs, shows no exceedances of permit limits. V. REGULATORY AUTHORITY/PERMIT ACTION In November 1972, Congress passed the Federal Water Pollution Control Act establishing the NPDES permit program to control water pollution. These amendments established technology- based or end-of-pipe control mechanisms and an interim goal to achieve “water quality which provides for the protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water” more commonly known as the “swimmable, fishable” goal. Further amendments in 1977 of the CWA gave EPA the authority to implement pollution control programs such as setting wastewater standards for industry and established the basic structure for regulating pollutants discharges into the waters of the United States. In addition, it made it unlawful for any person to discharge any pollutant from a point source into navigable waters, unless a permit was obtained under its provisions. Regulations governing the EPA administered NPDES permit program are generally found at 40 CFR §122 (program requirements & permit conditions), §124 (procedures for decision making), §125 (technology-based standards) and §136 (analytical procedures). Other parts of 40 CFR provide guidance for specific activities and may be used in this document as required. The applicant submitted a complete permit application on April 15, 2019. It is proposed that the permit be reissued for a 5-year term following regulations promulgated at 40 CFR §122.46(a). The existing NPDES permit initially issued July 29, 2014, with an effective date of September 1, 2014, and an expiration date of August 31, 2019. VI. DRAFT PERMIT RATIONALE AND PROPOSED PERMIT CONDITIONS A. OVERVIEW OF TECHNOLOGY-BASED VERSUS WATER QUALITY STANDARDS-BASED EFFLUENT LIMITATIONS AND CONDITIONS Permit No. NM0030848 Fact Sheet Page 6 of 16 Regulations contained in 40 CFR §122.44 require that NPDES permit limits are developed that meet the more stringent of either technology-based effluent limitation guidelines (ELGs), numerical and/or narrative water quality standard-based effluent limits, or the previous permit.