Document jNkya6QpkEZy1nxQzBkyXJd1R

REGION 6 DALLAS, TX 75270 April 8, 2025 TRANSMITTED VIA E-MAIL Honorable David Romero Mayor, City of Las Vegas 1700 North Grand Avenue Las Vegas, New Mexico 87701 mayor@lasvegasnm.gov RE: Administrative Order; Docket Number: CWA-06-2025-1736 NPDES Permit Number: NM0028827 Dear Mayor Romero: Enclosed is an Administrative Order (AO) issued to the City of Las Vegas for violations of the Clean Water Act (CWA) (33 U.S.C. 1251 et seq.). Violations were identified during a review of the permit file, noncompliance reports, and discharge monitoring reports submitted for the Las Vegas Wastewater Treatment Facility. The violations alleged are for failure to meet permit effluent limitations and unauthorized discharges. The Environmental Protection Agency (EPA) requests that you immediately confirm receipt of this e-mail and the attached order by a response e-mail to mcelroy.damon@epa.gov. This AO does not assess a monetary penalty; however, it does require compliance with applicable federal regulations. The first compliance deadline is within thirty (30) days of the effective date of the AO. The EPA is committed to ensuring compliance with the requirements of the National Pollutant Discharge Elimination System (NPDES) program and my staff will assist you in any way possible. Please reference AO Docket Number CWA-06-2025-1736 and NPDES Permit Number NM0028827 on your response. If you have any questions, please contact Mr. Damon McElroy, P.E. of my staff, at (214) 665-7159 or mcelroy.damon@epa.gov. Sincerely, Digitally signed by MARGARET OSBOURNE Date: 2025.04.08 16:02:54 -05'00' Cheryl T. Seager, Director Enforcement and Compliance Assurance Division Enclosure ec: shelly.lemon@env.nm.gov susan.lucaskamat@env.nm.gov UNITED STATES ENVIRONMENTAL PROTECTION AGENCY Region 6 FINDINGS OF VIOLATION AND COMPLIANCE ORDER Docket Number: CWA-06-2025-1736; NPDES Permit Number: NM0028827 STATUTORY AUTHORITY The following findings are made, and Order issued, under the authority vested in the Administrator of the United States Environmental Protection Agency (EPA), Section 309(a) of the Clean Water Act (the Act), 33 U.S.C. 1319(a). The Administrator of EPA delegated the authority to issue this Order to the Regional Administrator of EPA Region 6, who delegated this authority to the Director of the Enforcement and Compliance Assurance Division. waters of the United States. Any such discharge is subject to the specific terms and conditions prescribed in the permit. 7. Respondent applied for and was issued NPDES Permit No. NM0028827 (permit) under Section 402 of the Act, 33 U.S.C. 1342, with an effective date of December 1, 2022. At all relevant times, Respondent was authorized to discharge pollutants from the facility to waters of the United States only in compliance with the specific terms and conditions of the permit. FINDINGS 1. The City of Las Vegas (Respondent) is a "person," as that term is defined at Section 502(5) of the Act, 33 U.S.C. 1362(5), and 40 C.F.R. 122.2. 2. At all times relevant to this Order (all relevant times), Respondent owned or operated the Las Vegas Wastewater Treatment Facility (facility) located at 905 12th Street, Las Vegas, NM 87701, and was therefore, an "owner or operator" within the meaning of 40 C.F.R. 122.2. 3. At all relevant times, the facility acted as a "point source" of a "discharge" of "pollutants" with its final wastewater discharge directly to the Gallinas River, Segment No. 20.6.4.220, of the Pecos River Basin which is a "water of the United States," within the meaning of Section 502 of the Act, 33 U.S.C. 1362, and 40 C.F.R. 122.2. 4. Because Respondent owned or operated a facility that acted as a point source of discharges of pollutants to waters of the United States, Respondent and the facility were subject to the Act and the National Pollutant Discharge Elimination System (NPDES) program. 5. Under Section 301 of the Act, 33 U.S.C. 1311, it is unlawful for any person to discharge any pollutant from a point source to waters of the United States, except with the authorization of, and in compliance with, an NPDES permit issued pursuant to Section 402 of the Act, 33 U.S.C. 1342. 6. Section 402(a) of the Act, 33 U.S.C. 1342(a), provides that the Administrator of EPA may issue permits under the NPDES program for the discharge of pollutants from point sources to 8. Part I.A of the permit (Monitoring and Reporting Requirements) requires Respondent to sample and test its effluent and monitor its compliance with permit conditions according to specific procedures, in order to determine the facility's compliance or noncompliance with the permit and applicable regulations. The permit also requires Respondent to file with EPA, certified Discharge Monitoring Reports (DMRs) of the results of monitoring, and Noncompliance Reports when appropriate. 9. The permit contains "Effluent Limitations and Monitoring Requirements" that place certain limitations on the quality and quantity of effluent discharged by Respondent. The relevant discharge limitations are specified in Attachment A, which is incorporated herein by reference. 10. NetDMRs reported in compliance with the permit, show discharges of pollutants from the facility that exceed the permitted effluent limitations established in the permit, as specified in Attachment B, which is incorporated herein by reference. 11. CWA non-compliance reports filed by the Respondent with EPA in compliance with the permit show unauthorized discharges. These discharges are specified in Attachment C. 12. Pursuant to Part III.B of the permit, Respondent is required to at all times properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) which are installed or used by permittee as efficiently as possible and in a manner which will achieve compliance with the permit conditions. Docket No. CWA-06-2025-1736 Page 2 13. Pursuant to Part III.B of the permit, Respondent is prohibited from allowing a bypass except under specific circumstances. 14. Pursuant to Part III.C of the permit, Respondent is required to conduct monitoring according to test procedures approved under 40 CFR Part 136, unless other test procedures have been specified or approved. 15. On January 13, 2025, the New Mexico Environment Department on behalf of the EPA conducted a Compliance Evaluation Inspection of the facility's wastewater treatment plant, as documented in Attachment D, which is incorporated herein by reference. 16. As a result of the inspection, it was found that Parts III B and C of the permit were violated in that: a. Respondent failed to properly operate and maintain the wastewater treatment plant (and related appurtenances), b. Respondent failed to conduct sampling as required, c. Respondent allowed prohibited bypasses, d. Respondent failed to conduct monitoring and reporting according to approved test procedures. 17. On March 18, 2025, Respondent agreed to contact and coordinate with the Southwest Environmental Finance Center (SWEFC) for assistance with compliance with all permit conditions, including Effluent Limitations and Monitoring and Reporting Requirements, and for assistance with applying for available funding. Assistance is available through the SWEFC. Information on the SWEFC is available on the web-address https://swefc.unm.edu/home/, or by email at swefc@unm.edu, or by phone at 505-277-0644. 18. Each unauthorized discharge and each instance in which Respondent had a violation of the permit was a violation of Section 301 of the Act, 33 U.S.C. 1311. SECTION 309(a)(3) COMPLIANCE ORDER Based on the foregoing Findings and pursuant to the authority of Section 309(a)(3) of the Act, 33 U.S.C. 1319(a)(3), EPA hereby orders Respondent to take the following action: A. Take such measures as are necessary to comply with all permit conditions, including Effluent Limitations and Monitoring and Reporting Requirements, no later than thirty (30) days from the effective date of the Order. B. Within thirty (30) days of the effective date of this Order, Respondent shall submit a list of the specific actions taken to correct the effluent exceedances and unauthorized discharges. C. Within thirty (30) days of the effective date of this Order, Respondent shall provide written certification to EPA Region 6 that the violations cited herein have been corrected and the facility is compliant with the requirements of the permit. D. In the event the Respondent believes complete correction of the violations cited herein is not possible within thirty (30) days of the effective date of this Order, Respondent shall, within thirty (30) days of the effective date of this Order, submit a comprehensive written plan for the elimination of the cited violations within the shortest possible time. Such plan shall describe in detail the specific corrective actions to be taken and why such actions are sufficient to correct the violations. The plan shall include a detailed schedule for the elimination of the violations within the shortest possible time, as well as measures to prevent these or similar violations from recurring. E. Any information or correspondence submitted by Respondent to EPA under this Order shall be submitted, via email, to the following: Mr. Damon McElroy, P.E. mcelroy.damon@epa.gov GENERAL PROVISIONS Respondent may seek federal judicial review of the Order pursuant to Chapter 7 of the Administrative Procedure Act, 5 U.S.C. 701-706. Issuance of this Section 309(a)(3) Compliance Order shall not be deemed an election by EPA to waive any administrative, judicial, civil, or criminal action to seek penalties, fines, or other relief under the Act for the violations cited herein, or other violations that become known to EPA. EPA reserves the right to seek any remedy available under the law that it deems appropriate. Failure to comply with this Section 309(a)(3) Compliance Order or the Act may result in further administrative action, or a civil judicial action initiated by the United States Department of Justice. Docket No. CWA-06-2025-1736 Page 3 This Order does not constitute a waiver or modification of the terms or conditions of Respondents NPDES permit, which remain in full force and effect. Compliance with the terms and conditions of this Order does not relieve Respondent of its obligation to comply with any applicable federal, state, or local law or regulation. The effective date of this Order is the date it is received by Respondent. Date Digitally signed by MARGARET OSBOURNE Date: 2025.04.08 16:04:12 -05'00' Cheryl T. Seager, Director Enforcement and Compliance Assurance Division Attachment A City of Las Vegas WWTP NPDES Permit ID No. NM0028827 Effluent Characteristic Discharge Limitations Outfall: 001 Daily Avg. (30-day avg. unless noted) Daily Max. Aluminum 66.37 ug/l and 1.38 lbs/d 99.55 ug/l and 2.076 lbs/d Chlorine, total residual NA 11 ug/l Ammonia, total 4 mg/L and 83 lbs/d 6 mg/L and 125 lbs/d Total Suspended Solids 45 mg/L and 939 lbs/day (7-day) NA Disolved Oxygen 6 mg/L E. Coli 126 cfu/100 ml 410 cfu/100 ml pH shall be a minimum of 6.6 and a maximum of 9.0 standard units. Attachment B City of Las Vegas WWTP NPDES Permit ID No. NM0028827 Monitoring Period Parameters Monitoring 07/31/2023 07/31/2023 07/31/2023 07/31/2023 08/31/2023 08/31/2023 08/31/2023 08/31/2023 08/31/2023 09/30/2023 10/31/2023 10/31/2023 10/31/2023 10/31/2023 10/31/2023 10/31/2023 11/30/2023 11/30/2023 11/30/2023 12/31/2023 12/31/2023 12/31/2023 12/31/2023 12/31/2023 12/31/2023 12/31/2023 01/31/2024 01/31/2024 01/31/2024 01/31/2024 02/29/2024 Aluminum Aluminum Aluminum Chlorine, total residual Aluminum Aluminum Chlorine, total residual Nitrogen, ammonia total [as N] Oxygen, dissolved [DO] Chlorine, total residual Aluminum Aluminum Aluminum Chlorine, total residual Oxygen, dissolved [DO] pH Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Chlorine, total residual Oxygen, dissolved [DO] pH Aluminum Aluminum Aluminum Chlorine, total residual Aluminum 30DA AVG DAILY MX DAILY MX INST MAX 30DA AVG DAILY MX INST MAX DAILY MX MO MIN INST MAX 30DA AVG DAILY MX DAILY MX INST MAX MO MIN MINIMUM 30DA AVG DAILY MX INST MAX 30DA AVG 30DA AVG DAILY MX DAILY MX INST MAX MO MIN MINIMUM 30DA AVG DAILY MX DAILY MX INST MAX 30DA AVG Units ug/L lb/d ug/L ug/L ug/L ug/L ug/L mg/L mg/L ug/L ug/L lb/d ug/L ug/L mg/L SU ug/L ug/L ug/L lb/d ug/L lb/d ug/L ug/L mg/L SU ug/L lb/d ug/L ug/L ug/L Permit Limit DMR Value 66.37 2.076 99.55 11 66.37 99.55 11 6 6 11 66.37 2.076 99.55 11 6 6.6 66.37 99.55 11 1.38 66.37 2.076 99.55 11 6 6.6 66.37 2.076 99.55 11 66.37 96 2.37 150. 50 82.077 130. 40 7.8 4.83 40 135.33 3.19 260 30 3.42 6.58 95 140 50 2.136 308.667 14.598 2300. 50 2.16 6.45 91.533 2.208 310 50 70.583 Monitoring Period Parameters 02/29/2024 03/31/2024 03/31/2024 03/31/2024 03/31/2024 03/31/2024 03/31/2024 04/30/2024 04/30/2024 05/31/2024 05/31/2024 05/31/2024 05/31/2024 05/31/2024 06/30/2024 06/30/2024 06/30/2024 06/30/2024 06/30/2024 06/30/2024 06/30/2024 06/30/2024 06/30/2024 10/31/2024 11/30/2024 12/31/2024 12/31/2024 01/31/2025 01/31/2025 Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum pH Aluminum pH Aluminum Aluminum Aluminum Oxygen, dissolved [DO] Solids, total suspended Aluminum Aluminum Aluminum Aluminum Chlorine, total residual Oxygen, dissolved [DO] pH Solids, total suspended Solids, total suspended Chlorine, total residual Chlorine, total residual Chlorine, total residual Oxygen, dissolved [DO] E. coli Solids, total suspended Monitoring DAILY MX 30DA AVG 30DA AVG DAILY MX DAILY MX MO MIN MINIMUM DAILY MX MINIMUM 30DA AVG DAILY MX DAILY MX MO MIN 7 DA AVG 30DA AVG 30DA AVG DAILY MX DAILY MX INST MAX MO MIN MINIMUM 7 DA AVG 7 DA AVG INST MAX INST MAX INST MAX MO MIN DAILY MX 7 DA AVG Units Permit Limit DMR Value ug/L lb/d ug/L lb/d ug/L mg/L SU ug/L SU ug/L lb/d ug/L mg/L mg/L lb/d ug/L lb/d ug/L ug/L mg/L SU lb/d mg/L ug/L ug/L ug/L mg/L CFU/100mL mg/L 99.55 1.38 66.37 2.076 99.55 6 6.6 99.55 6.6 66.37 2.076 99.55 6 45 1.38 66.37 2.076 99.55 11 6 6.6 939. 45 11 11 11 6 410 45 150 12.292 1456.75 118.511 14000. 5.9 6.3 120 6.37 88.69 2.491 290 5.86 59.2 3.95 335.5 33.643 2900. 30 1.66 6.51 1672.4 73 60 20 280 3.5 2400 53.3 Attachment C City of Las Vegas WWTP NPDES Permit ID No. NM0028827 Date Volume (Gallons) SSO Impact Cause 12/3/2024 416,666 Gallinas River 1/3/2025 to 1/6/2025 4,700,000 Gallinas River 1/13/2025 1/17/2025 520,000 800,000 Gallinas River Gallinas River Hydraulic overflow caused solids in the WWTP clarifier(s) to flow over the weirs and into the effluent discharge. 3/10/2025 500,000 Gallinas River 3/29/2025 500,000 Gallinas River Attachment D City of Las Vegas WWTP NPDES Permit ID No. NM0028827 MICHELLE LUJAN GRISHAM GOVERNOR JAMES C. KENNEY CABINET SECRETARY March 14, 2025 Travis Martinez Utilities Director (Water) City of Las Vegas 905 12th Street Las Vegas, NM 87701 tmartintez@lasvegasnm.gov Original via Electronic Mail Re: City of Las Vegas - Wastewater Treatment Plant, Major, Individual Permit; SIC 4952; NPDES Compliance Evaluation Inspection; NPDES permit no. NM0028827; 01/13/2025 Dear Travis Martinez: Enclosed please find a copy of the report for the referenced inspection that the New Mexico Environment Department ("NMED") conducted at your facility on behalf of the U.S. Environmental Protection Agency ("USEPA"). This inspection report will be sent to the USEPA Region 6 Office in Dallas for their review. These inspections are used by USEPA to determine compliance with the National Pollutant Discharge Elimination System ("NPDES") permitting program in accordance with requirements of the federal Clean Water Act. The inspection report includes an introduction, observations, records review, sampling activities and analytical results, areas of concern, and closing conference and follow-up. Further explanations and problems noted during this inspection are discussed in this inspection report. You are encouraged to review the inspection report, required to correct any problems noted during the inspection, and advised to modify your operational and/or administrative procedures, as appropriate. If you have comments on or concerns with the basis for the findings in the NMED inspection report, please contact us (see the address below) in writing within 30 days from the date of this letter. Further, you are encouraged to notify both the USEPA and NMED in writing regarding modifications and compliance schedules at the addresses below: Rachel Matthews New Mexico NPDES Enforcement Coordinator U.S. Environmental Protection Agency Region 6 Water Enforcement Branch (6ECDWM) 1201 Elm Street, Suite 500 Dallas, Texas 75202 Matthews.Rachel@epa.gov 214-665-8589 Susan LucasKamat Program Manager New Mexico Environment Department Surface Water Quality Bureau (N2050) Point Source Regulation Section P.O. Box 5469 Santa Fe, New Mexico 87502 Susan.LucasKamat@env.nm.gov 505-946-8924 SCIENCE | INNOVATION | COLLABORATION | COMPLIANCE 1190 Saint Francis Drive, PO Box 5469, Santa Fe, New Mexico 87502-5469 | (505) 827-2855 | www.env.nm.gov City of Las Vegas - Wastewater Treatment Plant, NPDES # NM0028827 03/14/2025 Page 2 of 2 If you have any questions about this inspection report, please contact Nafis Fuad at 505-531-7956 or at nafis.fuad@env.nm.gov. Sincerely, Digitally signed by Susan Susan LucasKamat LucasKamat Date: 2025.03.14 07:36:47 -06'00' Susan A. LucasKamat Program Manager Point Source Regulation Section Surface Water Quality Bureau cc: Roberto Bernier, USEPA (6ECDWM) via email Bernier.Roberto@epa.gov Nancy Williams, USEPA (6ECDWA) via email Williams.Nancy@epa.gov Rachel Mathews, USEPA (6ECDWM) via email Matthews.Rachel@epa.gov Amy Andrews, P.E., USEPA (6ECDWM) via email Andrews.Amy@epa.gov David Esparza, P.E., USEPA (6ECDWM) via email Esparza.David@epa.gov McElroy, Damon, USEPA via email Mcelroy.Damon@epa.gov Brent Larsen, USEPA (6WDPE) via email Larsen.Brent@epa.gov Tung Nguyen, USEPA (6WDPE) via email Nguyen.Tung@epa.gov Susan A. Lucas Kamat, NMED SWQB Point Source Manager, via email Susan.LucasKamat@env.nm.gov Nafis Fuad, NMED SWQB Compliance and Enforcement Lead, via email Nafis.Fuad@env.nm.gov Shawnee Suazo, NMED SWQB Compliance and Enforcement Complex Facility Specialist, via email Shawnee.Suazo@env.nm.gov Luke Zhong, NMED SWQB Compliance and Enforcement Municipal and Industrial Specialist, via email Luke.Zhong@env.nm.gov Jason Martinez, NMED SWQB Permit and Certification Lead, via email Jason.Martinez2@env.nm.gov Avery Young, NMED GWQB PPS Domestic Lead, via email avery.young@env.nm.gov Andrew Romero, NMED GWQB PPS via email andrewc.romero@env.nm.gov Thomas Vigil, NMED EHB District II Manager, via email ThomasX.Vigil@env.nm.gov Joshalyn Slumberg, City of Las Vegas via email Jslumberg@lasvegasnm.gov James Lopez, City of Las Vegas via email Jlopez@lasvegasnm.gov Joshua McClenahan, City of Las Vegas via email JMcClenahan@lasvegasnm.gov Robert Espinoza, City of Las Vegas via email REspinoza@lasvegasnm.gov David G. Romero, City of Las Vegas Mayor via email mayor@lasvegasnm.gov Casandra Fresquez, City of Las Vegas Clerk via email cfresquez@lasvegasnm.gov 2 New Mexico Environment Department - Surface Water Quality Bureau INSPECTION REPORT Inspection Date(s): Media Program: Regulatory Program(s) 01/13/2025 Water CWA Company Name: Facility Name: Facility Physical Location: (city, state, zip code) Mailing address: (city, state, zip code) County/Parish: Facility Phone Number Facility Contact: City of Las Vegas City of Las Vegas Wastewater Treatment Plant East Frontage Road of I-25 Las Vegas, NM 87701 905 12th Street Las Vegas, NM 87701 San Miguel County 505-426-4729 Travis Martinez Utilities Director (Water) tmartintez@lasvegasnm.gov FRS Number: Identification/Permit Number: Media Identifier Number: NAICS: SIC: 110011026941 NM0028827 N/A 221320 4952 Personnel participating in inspection: Joshalyn Slumberg City of Las Vegas James Lopez City of Las Vegas Joshua McClenahan, City of Las Vegas Robert Espinoza City of Las Vegas Travis Martinez City of Las Vegas Nafis Fuad New Mexico Environment Department Shawnee Suazo New Mexico Environment Department Mauricio Tarazona New Mexico Environment Department Operator Associate Operator in Training Collections Supervisor Wastewater Manager Utilities Director (Water) Compliance and Enforcement Team Lead Complex Facility Specialist Permitting and Certification Team NMED Lead Inspector Signature/Date Nafis Fuad Nafis Fuad Digitally signed by Nafis Fuad Date: 2025.03.13 21:26:36 -06'00' Date: Supervisor Signature/Date Susan LucasKamat Date: 2025.03.14 07:35:43 -06'00' Digitally signed by Susan LucasKamat Susan LucasKamat Date: 6ENFORM-019-R8.2 (02/12/2020) 1 This page is intentionally left blank! City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 2 Section I - INTRODUCTION City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 PURPOSE OF THE INSPECTION New Mexico Environment Department (NMED) inspectors Nafis Fuad (lead inspector), Shawnee Suazo and Mauricio Tarazona arrived at the City of Las Vegas Wastewater Treatment Plant (the "Site" or "Facility") at 10:45 am on 01/13/2025 for an unannounced inspection. We met with Robert Espinoza, Utility Superintendent (Wastewater Division) to conduct the opening conference. I presented my credentials to Robert Espinoza and informed him that this was an NMED led inspection to determine compliance with the facility's National Pollutant Discharge Elimination System (NPDES) permit and the Clean Water Act (CWA). The scope of the inspection is a Compliance Evaluation Inspection (CEI) and includes an evaluation of the compliance of the facility with its NPDES permit and the CWA. FACILITY DESCRIPTION The City of Las Vegas has a total population of 12,000 - 13,000. The Facility serves a population of approximately 8,000-9,000. The rest of the population use septic systems and the facility has no immediate plans to connect them to the collection system. The facility has State of New Mexico ground water discharge permit 1118 (DP-1118). Ground water discharge permits are issued by the New Mexico Environment Department (NMED) Groundwater Quality Bureau (GWQB). The facility is accessible from I-25 north. Take exit 343 toward NM-283/I-25 BUS/NM-329/Las Vegas. Take a right onto S Grand Ave and then immediately turn right onto Frontage Rd/Frontage Rd 2137/Romeroville Frontage Rd. Drive 0.3 miles south on Frontage Rd/Frontage Rd 2137/Romeroville Frontage Rd and then take a left. The facility is on the left 0.7 miles down the unnamed road right across the rail tracks. See the aerial photo below. The design flow of this facility is 2.5 million gallons per day (MGD). The facility is defined as a major publicly owned treatment works (POTW) discharger. The facility has a total of four (4) lift stations within its sewer collection system. Raw wastewater enters the plant via a 12-inch Parshall flume with a pulsar electro sonic totalizer flow meter, then passes through an automated bar screen and a grit removal system. From the bar screen, the influent flows by gravity through a channel that directs the flow to the aerated grit chamber where inorganic material such as sand and gravel are removed. The grit pumps pull a slurry of grit from the bottom of the grit chamber and pumps it to the grit classifier and cyclone. The cyclone separates much of the water from the slurry and returns it to the waste flow stream. The solid material is sent to the classifier, where almost all the remaining water and lighter organic material are removed and returned to the waste stream. The remaining grit is washed as it is moved up the classifier by a screw auger and is disposed to a waste bin for disposal. The effluent from the grit chamber flows through the grease well and on to the treatment train. Grease and other floating material collected in the grease well is 3 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 skimmed from the surface with a telescoping valve that discharges to the grease pump station, which transfers the grease to the digesters. Solids are finally disposed of at a landfill owned by the city. The facility was upgraded in 2018 when the two (2) primary clarifiers and old racetrack aeration basin were repurposed for emergency overflow capacity of approximately 2 million gallons. From the headworks, wastewater travels to the east and west aeration basins for treatment. The 22 feet deep aeration (AB) basins have an aerobic zone, an intermediate zone, and an anoxic zone. The facility has three (3) blowers to provide air for the system. Decant flows by gravity to the two secondary clarifiers. Following the clarifiers is an inline micro disc filtration system. Effluent then passes through the ultraviolet (UV) disinfection system and flows through the 2' Cipolletti weir and secondary totalizer flow meter to the outfall. The effluent from the treatment plant is discharged into the Gallinas River in Segment No. 20.6.4.220 of the Pecos River Basin. The facility collects its effluent samples just above the weir. Reuse water is diverted before the weir and chlorinated before storage on-site. Waste Activated Sludge (WAS) is pulled from the aeration basins and sent to the aerobic digesters. Final disposal is at surface application sites owned by the city. Onsite In-house analysis is completed for the following: Dissolved Oxygen, effluent, daily pH, effluent, daily Total Residual Chlorine, effluent, Weekly E. coli, effluent, weekly Total Suspended Solids, effluent, Weekly Eurofins Albuquerque, Albuquerque, NM completes the following analysis three samples per week: Total Recoverable Aluminum, Effluent Eurofins Albuquerque, Albuquerque, NM completes the following weekly analysis: 5-day Biological Oxygen Demand, Effluent Total Cadmium, Effluent Total Ammonia, Effluent Total Mercuty, Effluent Bis(2-ethylhexyl) Phthalate Eurofins Albuquerque, Albuquerque, NM completes the following monthly analysis: Total Nitrogen (TN), Effluent Total Phosphorous (TP), Effluent Bio-Aquatic Testing, Inc., Carrollton, TX completes the following quarterly analysis: 4  Whole Effluent Toxicity (WET) tests City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 The staffing level for the facility is currently at four (4) staff with one (1) level 4 wastewater operator, One (1) level 1 wastewater operator, one (1) operator in-training, and one (1) contracted level 2 wastewater laboratory technician. There is one (1) uncertified staff who helps in the laboratory. The level 4 wastewater operator is the wastewater manager, Robert Espinoza, who also has a level 2 wastewater laboratory technician certification. The collections side of the city has one (1) employee currently. Working hours are from Monday through Friday, 7:00 am to 3:30 pm. Two (2) staff are on call during off hours and weekends. At full staffing the facility operations employ one (1) supervisor, one (1) manager, and four (4) operators, and the collections employ one (1) collection systems supervisor, one (1) collection system operator, and four (4) collections labors. Aerial photo City of Las Vegas Wastewater Treatment Plant Latitude 3533'59.68" N Longitude 10512'42.37" W East Clarifier Outfall 001 Section II - OBSERVATIONS After entry, we held an interview with the facility staff and inquired about recent non-compliances reported by the facility. The facility reported two overflows of solids from clarifiers though the outfall 001 into the Gallinas River, one on 12/03/2024 and the second from 01/03/2025 - 01/06/2025, with approximate volumes of 416,666 gallons and 4.7 million gallons respectively. The facility attributed these overflows to hydraulic overloading and other technical issues identified in a follow-up on -site training and technical assistance report (Appendix #6) prepared by Robert George from Oso del Agua LLC (OdA) on behalf of NMED GWQB. 5 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 During the interview Robert Espinoza informed us that although the permit design flow for the facility is 2.5 MGD, the facility operates without any issues up to 1.8 MGD. The average daily flow is 1.3-1.4 MGD. Seasonally, there is approximately 10-20% Inflow and Infiltration through the old lines. There have been some recent unexpected spikes in flow due to the unusual discharge from the City of Las Vegas Water Treatment Plant (WTP), which is also under the city utilities water division director. The utility director, Travis Martinez, informed us that the WTP regularly discharged supernatant from settled backwash water to the WWTP. The WTP recently installed a Veolia Actiflo pretreatment system which was run for 3 or 4 weeks and is suspected to have caused upsets in the filter beds of the WTP. Due to these upsets the WTP has started backwashing the filters at a frequency that is more than usual. Although the Actiflo was not operational during the inspection due to a diesel spill from the system, Travis Martinez informed us that it might go into operation once the spill is cleaned up by Clean Harbors. He also informed us that the contract with Veolia is for 3 years. There has also been unexpected spike in flow that the facility and the city utilities suspect to be originating from recent groundwater table rise. The facility has no plans for renovation or additional equipment to allow for increased wastewater flow. The wastewater superintendent, Robert Espinoza, explained to us that the WWTP can handle the supernatant from the WTP at a controlled way in a lower flow rate. He also informed us that the WWTP has requested to be informed of the unexpected discharge from the WTP prior to the discharge happening, during working hours when they can prepare for the events. The follow-up on-site training and technical assistance report (Appendix 6) also suggested similar measures. Robert Espinoza expects the WWTP to be able to handle 150-200 gallons per minute (GPM) discharge from the WTP during the day and 100 GPM during the night in order for the WWTP to recover from the shock hydraulic loading. He informed us that discharge from the WTP at times at times have incurred a total flow to the WWTP of 2.3 MGD for about three days continuously which, in his opinion, is beyond the capacity of the WWTP to handle. Travis Martinez explained that WTP has managed to bring down the flow of the discharge from the WTP to the WWTP to 200 GMP from 450 GPM initially. He also explained that the WTP is looking into installing a smaller sized pump to support a continuous low flow as opposed to a shock hydraulic loading to the WWTP. We confirmed that the facility has approximately 100 miles of collection system with four (4) lift stations. Three (3) of the lift stations are on Supervisory Control and Data Acquisition (SCADA) system. Two (2) on call operators and the superintendent Robert Espinoza receives a call from the SCADA system in case of any emergency. The facility informed us that there were three (3) overflows from the plant in 2024 - one (1) in the collection system during a 4-inch rainfall, one (1) in the plant around the same time, and one (1) in the 6 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 plant in fall that was contained in the facility grounds. We informed the facility that NMED Surface Water Quality Bureau (SWQB) did not have records of all the overflows and requested the facility's Standard Operating Procedures (SOP) for overflow reporting. The facility informed us that in case of an overflow the superintendent writes down the information and sends it to the laboratory manager who reports the information to the contacts on the written SOP. However, the email address for SWQB was incorrect. We provided the facility with the correct email addresses for SWQB and for the USEPA enforcement officer assigned to the facility. The facility also mentioned that potential sanitary sewer overflow (SSO) locations are at one or two manholes near the river. During the inspection the facility had no written SSO remediation policies and emergency SOPs. The utility director, Travis Martinez, informed us that the utility department is working on such an SOP. The utility director also informed us that the goals of the facilities program for managing, operating and maintaining the sanitary sewer conveyance system was to update manholes, install SCADA for the fourth lift station, and build up inventory. The facility informed us that there were no identified structural deficiencies in the collection system. The facility also informed us that it has an Operation and Maintenance (O&M) schedule for upgrading and replacing or repairing parts and equipment. The city utility department has recently hired an inventory specialist in order to develop an inventory. The facility has received a request for proposal (RFP) for upgrading the UV system from Kingdom Technology Services. The facility is also trying to procure a fan press. The facility has a diesel generator that can provide backup power to the plant for an estimated 24 hours. The fuel capacity of the generator is 250 gallons, and the facility has a 75-gallon transfer tank. However, the generator does not provide backup power to the blower currently. The facility has also acquired funding for two (2) more generators. Each lift station has its own generator, which are tested automatically and are contracted for maintenance work. We observed the decommissioned primary clarifiers had wastewater in them. Rober Espinoza explained that due to the pump being taken offline when those clarifiers were decommissioned, when the facility is hydraulically overloaded, the primary clarifiers receive wastewater which are then pumped to the digestor directly, bypassing the treatment system. Robert Espinoza informed us that the pumps are still housed and can be brought into operation. During the inspection we observed another overflow of solids from the overflowing clarifier being discharged into the Gallinas River through the outfall 001 at around 2:45 pm. We observed the east clarifier to overflow solids. Robert Espinoza explained the difficulty the facility is facing to adequately distribute flow to the east and west clarifier. Per the follow-up on-site training and technical assistance report (Appendix 6), approximately 2/3 of the flow is diverted to the east clarifier. That report also identified that the sludge blanket in the east clarifier is only a few feet below the surface by midmorning, suggesting the hydraulic overload is affecting this clarifier more adversely. The report identified replacing the secondary clarifier splitter box to be a possible solution to remediate this issue. 7 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 We observed one of the recommendations from the technical assistance report, blocking an opening in the flow box just upstream of the splitter box with wooden plank to restrict overflow to the decommissioned racetrack aeration basin (Photo #3), was addressed by the facility. However, we observed even with this effort to block, some portion of the flow was entering into the decommissioned racetrack aeration basin. We also observed the content of the flow box was abruptly moving vertically, showing the effect of the hydraulic overloading at the plant. The flow box has two inlets, one from the influent and the other from the decommissioned racetrack, and one outlet which goes to a flow splitter box for secondary clarifiers. We also observed overflowing solids into the UV housing during the overflow event. The facility informed us that after the overflow events the facility cleans the UV housing. We observed the proper placement of flow measurement device. We confirmed that the secondary flow measuring device is not compared to confirming the reading to be 10% of the primary weir. We observed solids in the effluent at the primary effluent flow measurement device, the weir. We observed the laboratory technician, Alyssa Chavez, and the laboratory uncertified staff taking sample of the effluent during the discharge event. We observed the autosampler (Global Water WS700) used to collect composite samples, stationed next to the sampling location did not have any thermometer to monitor the sample temperature. We visited the outfall 001 and observed discolored effluent containing solids being discharged into the Gallinas River. RECORDS REVIEW I reviewed facility records. We reviewed the laboratory calibration and maintenance records and found them to be adequate. We observed that personnel handling samples and performing analyses have proper training or certification. We observed records are maintained as required by permit. I reviewed the laboratory benchsheets, external laboratory reports, and discharge monitoring report (DMR) calculation spreadsheet for December 2024, and observed calculations are not performed per permit requirements (Appendix #5). Analytical results were not consistent with data reported on DMRs. These errors are described below. The facility used influent flow recorded on benchsheets as flow, in conduit or through the treatment plant, on their DMRs. The facility calculated the loading values for BOD and TSS correctly in their spreadsheet, however, they used the wrong flow value for BOD. Analysis result for BOD provided by external laboratory Eurofins Albuquerque and the chain of custody form indicates that a sample was collected for BOD on 12/03/2024, the DMR calculation spreadsheet provided by the facility shows the results for the BOD analysis sample collected on 12/03/2024 was used with flow value from 12/04/2024. 8 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Also, the facility calculated the 30-day average for BOD and TSS incorrectly (BOD - 62.1 lb/day and TSS - 19.96 lb/day) and reported the incorrect data on the DMR. The correct values for those two pollutant loads should be 120.96 lb/day for BOD and 24.67 lb/day for TSS, respectively. Furthermore, the facility measures only one sample per month for total nitrogen (TN) and total phosphorus (TP). However, in December 2024 the facility reported an incorrect value for the averages for TN and TP. Analysis result for BOD provided by external laboratory Eurofins Albuquerque indicates that sample collected for BOD on 12/03/2024 was prepped or analyzed beyond the specified holding time. This does not meet regulatory requirements. In December 2024, the facility monitored only 3 weeks of effluent sample for E. coli bacteria. I reviewed the facilities Discharge Monitoring Reports (DMRs) and observed the facility had numerous exceedances from the permit limits for Dissolved Oxygen (Concentration), pH (minimum), Total Suspended Solids (7-day average concentration and loading), Total Recoverable Aluminum (30-day average and daily maximum, concentration and loading), Total Residual Chlorine (Concentration). Section III - AREAS OF CONCERN The following areas of concern were identified in this inspection: 1. The facility is discharging effluent containing solids that is not permitted by the NPDES permit through the outfall. (Photo #12 & #13; Appendix #4) 2. The autosampler for collecting composite samples had no method of meeting the sample storage requirements per 40 CFR Part 136. (Photo #11) 3. The facility did not have any hydraulic overload mitigation plan or any other SSO remediation plan. (Appendix #6) 4. The facility did not take measure to inform the public and downstream users while discharging effluent that does not meet permit requirements and has the potential to harm human health and the environment. 5. The facility has no written SOP for the WWTP operation or communication between the WTP and the WWTP. (Appendix #6) 6. Wastewater going into the decommissioned primary clarifiers are pumped directly to the digestor bypassing the treatment system. (Photo #1) 7. Flow distribution between the secondary clarifiers needs to be adequately addressed. (Appendix #6) 8. The facility had numerous exceedances from the permit limits between September 13, 2023, and January 13, 2025. (Appendix #3) 9. The facility has exceeded its design flow of 2.5 MGD numerous times. (Appendix #3) 10. Facility has reported value in DMR that does not meet regulatory requirements. (Appendix #5) 9 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 11. The facility has used pollutant concentrations analyzed and flow values recorded on different days in order to calculate pollutant loading. (Appendix #5) 12. The facility needs to monitor its effluent at the required frequency per the NPDES permit. (Appendix #5) 13. The facility needs to report effluent flow recorded as flow, in conduit or through treatment plant. (Appendix #3 & #5) CLOSING CONFERENCE: NMED inspectors Nafis Fuad (lead inspector), Shawnee Suazo and Mauricio Tarazona conducted a closing conference at the City of Las Vegas Wastewater Treatment Plant at 3:15 pm on 01/13/2025 for the inspection. During the closing conference, I reviewed the #1 - #6 Areas of Concern noted during the inspection. Additionally, I noted the additional AOCs #7 - #9, after the onsite inspection which were not included in the closing conference. Section IV - FOLLOW UP I received the following information on 01/27/2025, after exiting the Facility on 01/13/2025: 1. Schematic of treatment process and a map of facility 2. Physical description of the units and process (description extracted from permit application is acceptable) 3. Copies of Operator Certifications or other training documentation evidence for all personnel who make operational changes at the WWTP. 4. Copies of Laboratory Technician Certifications or other training documentation evidence for all personnel who collect samples or run laboratory analyses (including personnel who only run some parameters like pH). 5. Evidence of the facility's stormwater permits. 6. Documents related to RFP for UV system. 7. Submitted and signed DMRs from October 2024 to December 2024 along with all documentation directly related to the creation of these specific DMRs, including: o Laboratory Bench Sheets (handwritten &/or typed) used to construct DMRs from above. - including related copies of the Laboratory Blue Book o Laboratory Sampling Reports used to construct DMRs (i.e., lab reports from external labs). o Excel (or other database) spreadsheets used to construct DMRs listed above. o Chain of Custody records (usually included as last page of Laboratory Report) o Calculation sheets used to calculate volumes for composite samples, or other records used to verify composite times/volumes used in autosamplers. 8. WET Testing Laboratory reports from January 2024 to December 2024. 9. Submitted and signed Sludge DMR with metals, pathogens and vector report from the last 1_year. o Sludge sampling Laboratory Sampling Reports 10. Flow meter logs showing daily flow rates from October 2024 to December 2024_. 11. Calibration sheets for effluent primary and secondary flow meters within the last 1_year. 12. Calibration sheets for laboratory equipment within the last 1 year. 10 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 13. Excursion, Overflow or Bypass Summary Reports from October 2024 to December 2024. I received an SOP for reporting noncompliance and a template for Public Service Announcement (PSA) to be used during future discharges of such kind into the Gallinas River (AOC #4) on 02/06/2025. I have received weekly reports from the facility on this noncompliance related to discharge of effluent with overflowing solids into the Gallinas River, detailing the facility's efforts to mitigate them and prevent any further noncompliance, until 02/07/2025. The facility reported another noncompliance related to the solid overflow for 8 hours on 03/10/2025 with an approximate volume of 500,000 gallons. I have requested additional information on the event, inquiring the precise reasons for the noncompliance and the efforts on 03/11/2025. The facility has attributed this noncompliance to hydraulic overloading as well. The facility has not used the PSA template to notify any downstream users. Section V - LIST OF APPENDICES Appendix 1 - Photo Log Appendix 2 - Opening and closing conference sign-in sheets Appendix 3 - Effluent Violations from September 13, 2023, to January 13, 2025 Appendix 4 - Permit No. NM0028827 effective 12/01/2022, pages 1 - 2 Appendix 5 - Example of received reports and bench sheets and facility schematic diagram Appendix 6 - Follow-up on-site training and technical assistance report prepared by Robert George from Oso del Agua LLC. (OdA) on behalf of NMED - GWQB. 11 This page is intentionally left blank! City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 12 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Appendix 1 Photograph Log 13 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 1 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0676 State: New Mexico Date: 01/13/2025 Decommissioned primary clarifier accumulating wastewater during hydraulic overloading. Refer to AOC #5. 6ENFORM-019-R8.2 (02/12/2020) 14 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 2 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0678 State: New Mexico Date: 01/13/2025 Overflow Measure to block the overflow Overflow of wastewater from the flow box into the decommissioned racetrack aeration basin despite the effort to block the opening from on the flow box with a wooden plank. 6ENFORM-019-R8.2 (02/12/2020) 15 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 3 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0679 State: New Mexico Date: 01/13/2025 Flow box with device to block overflow into the decommissioned racetrack aeration basin. 6ENFORM-019-R8.2 (02/12/2020) 16 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 4 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0680 State: New Mexico Date: 01/13/2025 Aeration Basin Aeration basin. 6ENFORM-019-R8.2 (02/12/2020) 17 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 5 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0682 State: New Mexico Date: 01/13/2025 Treatment in the aeration basin. 6ENFORM-019-R8.2 (02/12/2020) 18 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 6 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0690 State: New Mexico Date: 01/13/2025 Unsettled solids in the east clarifier. 6ENFORM-019-R8.2 (02/12/2020) 19 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 7 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0687 State: New Mexico Date: 01/13/2025 Unsettled solids overflowing with the effluent from the east secondary clarifier. 6ENFORM-019-R8.2 (02/12/2020) 20 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 8 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0692 State: New Mexico Date: 01/13/2025 Solids in the UV channel and disc filter housing during the overflow event. 6ENFORM-019-R8.2 (02/12/2020) 21 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 9 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0694 State: New Mexico Date: 01/13/2025 UV train Disc Filter Solids Solids in the UV channel and disk filter housing during the overflow event. 6ENFORM-019-R8.2 (02/12/2020) 22 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 10 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0695 State: New Mexico Date: 01/13/2025 Flow measuring weir Effluent containing solids going to the outfall Solids in the flow measuring device, which is also the sampling location for monitoring requirements. 6ENFORM-019-R8.2 (02/12/2020) 23 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 11 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0696 State: New Mexico Date: 01/13/2025 Autosampler (Global Water WS700) used to collect composite samples, stationed next to the sampling location with no thermometer to monitor the sample temperature. 6ENFORM-019-R8.2 (02/12/2020) 24 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 12 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0697 State: New Mexico Date: 01/13/2025 Discolored effluent containing solids being discharged into the Gallinas River though outfall 001. 6ENFORM-019-R8.2 (02/12/2020) 25 New Mexico Environment Department - Surface Water Quality Bureau Photograph Log Photo No. 13 Location City of Las Vegas Wastewater Treatment Plant City: Las Vegas County/Parish: San Miguel County Photographer: Nafis Fuad File Name: IMG_0700 State: New Mexico Date: 01/13/2025 Discolored effluent containing solids discharged into the Gallinas River though outfall 001, directly downstream of outfall 001. 6ENFORM-019-R8.2 (02/12/2020) 26 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Appendix 2 Opening and closing conference sign-in sheets 27 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 New Mexico Environment Department Surface Water Quality Bureau - Point Source Regulation Section 1190 S St Francis Dr., Santa Fe, NM - 87505 NPDES Inspection attendance sheet FACILITY: Lo..,; ~ \,() W~ ASSOCIATED PERMIT#: NM OQ~38~f LEAD INSPECTOR: Ne...~!> F ~ Date(s) of Inspection : _D_l_/,_1_3~/~:_?.t->-~- - - -- - -- - - - ATTENDEES Affiliation Title , Phone# email Opening Closing conf. Conf. ------ ,/"" - --- .....--- -- --.,,-..-- ....-- ...--- ..,,-- .,,,....-- 28 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Appendix 3 Effluent Violations from September 13, 2023, through January 13, 2025 29 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 . Permit Name Versie Curr. Major n . Nmbr Minor Status Issue Date Effective D ate . . Expiration Date ~IIIE~~lfmmDIII~ Version #0 Outfall 001A 00300 Oxygen, dissolved [DO) / Location 1 / Season O/ Base r@ifflHI Ml#ffllffll 2/1/2022 111/30/2027 ili+i1H1iUiHffl91 ! Dai ly Limit Unit Desc Statistical Base Limit Value 9/30/23 10/31/23 11/30/23 12/31/23 1/31/24 2/29/24 3/31/24 4/30/24 5/31/24 6/30/24 7/31/24 8/31/24 9/30/24 10/31/24 11/30/24 12/31/24 Milligrams per Liter MO MIN 6. 6.82 3.42 . 6 6 04 5.9 6 02 5. 86 1.66 NODl=3 3.5 00400 pH / Location 1 / Season 0 / Base rMEltMI-M 12/1/2022 I1M1/3i=0/2tf0f2i7F IDmall-1Mii111Mm!4 Unit Standard Units 9. 7. 19 7. 6 7.31 7.03 7.35 7.38 7.56 6.98 7.51 7.63 7.8 7 7.2 7.65 7. 63 7. 30 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 00530 Solids, total suspended / Location 1 / Season 0 I Base ., . Weekly Pounds per D Pounds per Day 0 V 7 DA AVG 939. Milligrams per Milligrams per Liter 30DA AVG 7 DA AVG 30. 45. 34.68 77.67 59.33 14 .4 63.517 140.218 70.23 38.4 520.8 1672.4 110.8 79.1 46.3 2.9 7.48 5.76 8.21 4.79 9.57 4.49 3.9 14.7 21 .83 4.8 3.8 2.8 3.7 3.8 1.7 .6 10.2 7.1 14. 6.4 24.58 7.96 4.4 59.2 73 7 5.7 5.1 3.6 4 2.5 01104 Aluminum, total recoverable I Location 1 / Season 0 I Base Limit Start Date 12/1/2022 Limit Limit Unit Desc Statistical Base Limit Value DMRValues 9/30/23 10/31/23 11/30/23 12/31/23 1/31/24 2/29/24 3/31/24 4/30/24 5/31/24 6/30/24 7/31/24 8/31/24 9/30/24 10/31/24 11/30/24 12/31/24 Limit End Date 11/30/2027 Sample Type Grab Frequency of Analysis Three per Week Pounds per D Pounds per Day 30DAAVG DAILY MX 2.076 I 9 .. .782 3.19 1.389 14.598 2.208 1.502 118.511 1.06 2.491 33.643 1.24 .4 .5 2 .52 .74 1.52 icrograms p icrograms per Li er 30DAAVG DAILY MX 66.37 99.55 46.667 135.33 5 308.667 91.533 70.583 1456.75 59.07 88.69 335.5 65.23 15.5 37.33 29.21 25 .71 10.73 87 260 2300 310 150 14000 120 290 2900 92 47 60 61 45 62 31 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 50060 Chlorine, total residual / Location A/ Season 0 I Base 50050 Flow, in conduit or thru treatment plant/ Location 1 / Season 0 I Base Limit Limit Unit Desc Statistical Base Limit Value DMRValues 9/30/23 10/31/23 11/30/23 12/31/23 1/31/24 2/29/24 3/31/24 4/30/24 5/31/24 6/30/24 7/31/24 8/31/24 9/30/24 10/31/24 11/30/24 12/31/24 Million Gallon Million Gallons per Day Million Gallons 30DAAVG 7 DAAVG DAILY MX .001 .959 . 87 1.0 .938 .912 .68 .03 1.32 1.49 1.26 .11 1.5 1.3 1. 16 1.1 .997 1.053 1.25 1. 1. 69 1. 78 1. 1. 1. 32 1.17 1. 7 1. 1. 0 32 6 .698 1.281 2. 88 2.024 2.155 1.116 1.319 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Appendix 4 Permit No. NM0028827 effective 12/01/2022, pages 1 - 2 33 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 ~N=P=D=E=S~P~E=R=M=IT~N~o-~N~M=0=02=8=8=2~7_ _ _ _ _ _ _ _ _ _ _ _~P~a=g~elof PARTI PART I-REQUIREMENTS FOR NPDES PERMITS SECTION A. LIMITATIONS AND MONITORING REQ UIREMENTS 1. FINAL Effluent Limits - 2.5 MOD Des ign Flow During the period beginning the effective date ofthe pem1it and lasting through the expiration date of the pennit (unless otherwise noted), the pem1ittee is authorized to discharge treated municipal wastewater to the Gallinas River, in Segment Number 20.6.4.220, from Outfall 001. Such discharges shall be limited and monitored by the pennittee as specified below: I EFFLUENT CHARACTERISTICS STORET POLLUTANT CODE pH I 00400 DISCHARGE LIMITATIONS Standard Units MINIMUM 6.6 I MAXIMUM I 9 I MONITORING REQUIREMENTS MEASUREMENT FREQUENCY SAMPLE TYPE Daily I Grab ~N~P~D~E~S~P~E~RM~I~T~N_o~-~N~M~0~0~2~8~82_7_ _ _ _ _ _ _ _ _ _ _ _ _P~a~g~e2of PARTI EFFLUENT CHARACTERISTICS POLLUTANT Flow Biochemical Oxygen Demand, 5-dav Biochemical Oxygen Demand, 5-day, % removal, minimum Total Suspended Solids Total Suspended Solids,% removal, minimum E Coli Bacteria (*2) Total Recoverable Aluminum Total Cadmium Total Residual Chlorine Total Ammonia Total Mercurv Bis(2-ethvlhexvl)Phthalate Dissolved Oxygen (minimum) Total N itrogen (*9, *10) Total Phosphorous (*9) STORET CODE 50050 003 10 DISCHARGE LIMITATIONS lbs/day, unless noted mg/I, unless noted (*l) 30-DAY DAILY 7-DAY AVG 30-DAY AVG DAILY MAX AVG MAX Report Report Report NIA NIA MGD MGD MGD 417 NIA 542 20 NIA 7-DAY AVG NIA 26 50076 2: 85% (*5) NIA NIA NIA NIA NIA 00530 81011 51040 01105 01027 50060 006 10 71900 39100 00300 00600 00665 626 2: 85% (*5) NIA 138 0.0 102 NIA 83 0.0160 0.484 NIA 145 23.9 NIA NIA NIA 2.076 0.0153 NIA 125 0.0186 0.726 NIA Report Report 939 30 NIA 45 NIA NIA NIA NIA NIA 126 (*2) 410 (*2) NIA cfu/l00m l cfu/100 ml NIA 66.37 ug/1 99.55 ug/1 NIA NIA 0.491 ug/1 0.736 ug/1 NIA NIA NIA 11 ug/1 (*3) NIA NIA 4 6 NIA NIA 0.770 ug/1 0.891 ue/1 NIA NIA 23.22 ug/1 34.83 ug/1 NIA NIA 6.0 NIA NIA NIA 130 Report NIA NIA 2.14 Report NIA MONITORING REQUIREMENTS MEASUREMENT SAMPLE FREQUENCY TYPE Continuous Totalizing Meter One/Week 24-Hour Comnosite One/Week Calculation (*5) One/Week One/Week One/Week 24-Hour Composite Calculation (*5) Grab Three/Week Grab One/Week Daily (*3) One/Week One/Week One/Week Daily Grab Instantaneous Grab (*3) Grab Grab Grab Grab One/Month One/Month 24-Hour Composite 24-Hour Comoosite WHOLE EFFLUENT TOXIOTY TESTING !1-Dav Chronic Static Renewal/NOEC) (*4) Ceriodaphnia dubia Pimephales promelas VALUE Report Report MEASUREMENT FREQUENCY Once/Quarter Once/Quarter SAMPLE TYPE 24-Hr Composite 24-Hr Composite 34 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Appendix 5 Example of received reports and bench sheets and facility schematic diagram 35 Vegas Wastewater Treatm ent Plant ~oo ~ (Last M onth) ... v ...~ 8699654180 Influent ,- - 11 value is calculated AsN NH3 red number means daily sheetmissing, _couldnot..::::tify --- -- ---~- ~--- ~- - ---- -- - - Effl enl Blue Numbers n City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 "NETDMR-DataSheet 2024.xlsx - Dec" - Page 1 36 Date Day 1 Sun 2 Mon 3~ e 4 Wed 1....,. 5 Thu 6 Fri 7 Sat 8 Sun 9 Mon 10 Tue 11 Wed 12 Thu 13 Fri 14 Sat 15 Sun 16 M on 17 Tue 18 W ed 19 Thu 20 Fri 21 Sat 22 Sun 23 M on 24 Tue 25 W ed 26 Thur 27 Fri 28 Sat 29 Sun 30 Mon 31 Tue 30-day:M:in 30-day Avg 30-day Max 7-day Avg T ot ali z e r F low M GD ,ff fl = 8701112320 1.458 8702974980 1.863 8703675840 0.701 8706625540 2.950 8708204540 1.579 8709647360 1.443 8710991870 1.345 8712240130 1.248 8713451520 1.211 87 15042820 1.591 8716338180 1.295 8717576190 1.238 87 19353860 1.778 8720693250 1.339 8721909760 1.217 8723090430 1.18 1 8724296700 1.206 8725478400 1.182 8727078910 1.601 872836 1980 1.283 8729908220 1.546 8731 159550 1.251 8732249090 1.090 8733446 140 1.197 8735412220 1.966 8736487420 1.075 8737452000 0.965 8739039230 1.587 8740289540 1.250 874 1464060 8742634 500 1. 175 1.170 0701 1.386 2.950 7D avg MGD BOD mg/L TSS mg/L TDS mg/L TP mg/L Chlori de mg/L TKN mg/L Nitr ate / Nitr ite mg/L Ammonia mg/L pH DO Temp units m IL del1-C TRC moll. NTU units BOD mo/L 7D avg m"/L BOD lbs 7Davg lbs TSS m IL 7D avg TSS m IL lbs 53.00 27.00 750.00 6.70 130.00 53 .00 0.00 1.604 490.00 236.33 1.448 68 00 45 83 1364 120.00 194 67 1358 18275 125 96 1.604 31.00 7.21 12.80 7.37 6.90 7.39 740 7.21 12.80 7.38 5.60 7.21 6.90 7.22 6.80 7.41 6.70 7.35 6.00 744 7.00 7.40 6.10 7.36 7.40 7.30 840 7.33 8.00 720 890 7.40 5.70 7.25 6 00 720 890 7.26 7.40 7.22 640 7.21 6.90 7.36 6.10 7.31 720 7.39 6.30 7.32 6.00 7.05 4.90 7.30 350 7.33 4.30 7.24 7.90 7.32 8.10 7 05 3.50 7.32 8.10 7.44 12.80 14.40 16.20 12.70 14.40 16.30 16.00 16.00 17.40 14 .60 14.70 17.70 14.00 13.10 12.90 10.90 14.40 17.30 10.90 14 .30 11.92 12.55 17.50 13.30 1620 15.00 15.60 16 . 10 13.40 13.60 14.20 0.00 0.19 0.00 0.45 0.00 1.18 16.00 16.00 393.65 0.00 0.19 0.00 0.05 0.00 0.22 0.00 0.51 0.00 0.45 0.00 0.16 0.00 0.52 0.00 0.00 0.00 0.00 0.51 0.00 0.7 1 0.00 0.72 0.00 049 0.00 0.73 0.00 0.51 000 1.12 0.00 000 0 00 0.00 0.73 0.00 0.89 000 032 0.00 0.41 0.00 0.66 0.01 0.75 0.01 032 5.50 5.50 90 18 0.00 0.64 0.0 1 0.54 0.00 069 0.00 0.52 0.28 0.81 0.00 1.24 393 .65 1-20 1.20 0.00 1.4 7 147 0.00 2.4 7 247 90.18 1.77 1.77 - 5.38 62.15 . 1.73 280.00 16.00 393.65 2. 47 29.52 15.84 24.35 28.96 ( 1996 , - BOD Removal 0.97 TSSRemoval 0.99 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Chain of custody for 12/03/2024 samples 37 Chain-of-Custody Record Client: City of Las Vegas Turn-Around Time: C Standard Project Name: LfRush Mailing Address: 905 12th sl Las Ve as, NM 87701 Phone#: 505)410-6531 email or Fax# al'i'SSa .chavez@smao12eralions .com QA/QC Package: D Standard Accreditation: cJ NELAC EDD (Type) D Level 4 (Full Validation) u /l,Z, Compliance Other __ Date Time Matrix Sam le Name Effluent Effluent Effluent Effluent Effluent Effluent n uen DMR Project# Project Manager: Alyssa Chavez <! Sampler: ---Al,11 on Ice: Eil'Yes 0 0 . # of Coolers: 1 Cooler Tern p(;,dud ng c,i:f. lf -,:;.I ~ J., 0 ~ Container Preservative Type and# Type HEAL No. 1Lamber NIA -z 1 Liter H2S04 'Z 250 ml HNOJ I 250 ml HN03 7.. 03 :, 1 Liter NIA L 1 Liter N/A ~ HALL ENVIRONM,. -~ ... ANALYSIS LABOF 11 www.hallenvironmental.com 4901 Hawkins NE - Albuquerque , NM f ~~-,s-.:6coc Tel. SOS-345-3975 Fax 505-345-4107 Analysis R~ques.t :<:!,:" ]<'> ~ 4> ::c ~ z 'lii E E e " ;;, ::, a._ 0) <: ...J .E I :, Cl w -:ii 0 Cl <i: (.) ca X X X X X X X X Date : ~ I,) t0 D ~ D t0 JS. Time: 9:30 Time: Remarks: S"" "" -''c i~ /, J:J:J, ,,,,Jd . :x....r ,..,;,...,-::;;;.I :1-13 ...,.,. ,.,,!I ~<o u: ~ UJ/ c, <. -">lh'f I f ~. umpl@s. SIJbtn~tteCI to Hall Env11rcinm~I m~ be ~boontracted ~a other accredimd tabor.atories.. This ,'ie:-ve:s al!i nat.ce of ttiio poil!iib~ity. An)' sub-contracted data will be, clea:ty no1.a\ed on the: analytical repor-. m City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Eurofins Albuquerque analysis report for 12/03/2024 samples - Page 7 Client: City of Las Vegas, NM ProjecUSite DMR Client Sample ID: Effluent Date Collected ~ Date Received: 12/06/24 08 :43 Sample Results Method: EPA 625.1 - Semivolatile Organ ic Compounds (GC/MS) Analyte Result Qualifier Rl Bis(2-ethylhexyl) phthalate ND H 0.0050 Nill Unit 0.00028 mg/L SUffogate 2,4,6-Tribromophenol (Surr) 2-F/uorobiphenyl (Surr) 2-F/uorophenol (Surr) Nlrobenzene-<15 (S urr) p-Terphenyl-d14 (Surr) Phenol-<15 (Surr) Recovery 68 69 34 57 88 18 Qualifier Limit.s 31-132 29-112 28 -114 15-314 20- 141 8-424 Method: EPA 200.7 Rev 4.4 - Metals l[ Analyte Alum inum General Chemistry Analyte Biochemical Oxygen Demand (SM 5210B) Ammonia (SM4500 NH3 C LL) (ICP) - Total Result 0.018 Result Q ND Recoverable Qualifier J Qualifier H H3 5 Rl 0.020 Rl 2.0 0.27 Nill Unit 0.017 mg/L Nill Unit 2.0 mg/L 0.12 mg/L Job ID: 885--16446-1 Lab Sample ID: 885-16446-2 Matrix: Water D Prepared 12/11/24 07:29 Analyzed 12/11/2415:52 Prepared 12111/24 07:29 12111/24 07:29 12111/24 07:29 12111/24 07.29 12111/24 07.29 12111/24 07:29 Analyzed 12111/24 15:52 12111/24 15:52 12111/24 15:52 12111/24 15:52 12111/24 15:52 12111/24 15:52 011 Fae 11 Di/Fae D Prepared 12/10124 06:46 Analyzed 12112/24 13:07 Oil Fae D Prepared Analyzed 12/11 /2414:18 12/10124 14:19 12/11/2410:35 Oil Fae Page 7 of 22 38 Eurofins Albuquerque 12/20/2024 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Eurofins Albuquerque analysis report for 12/03/2024 samples - Page 4 Client: City of Las Vegas, NM Project/Site: DMR Qualifiers GC/MS Semi VOA Qualifier Qualifier Descr1ptlon Continuing Calibration Verification (CCV) is outside acceptance limits, low biased. Result is less than the RL but greater than or equal to the MDL and the concentration is an approximate value. General Chemistry Qualifier Qualifier Description H Sample was prepped or analyzed beyond the specified holding time. This does not meet regulatory requirements. H3 Sample was received and analyzed past holding time. This does not meet regulatory requirements. Glossary Abbreviation ;~ %R CFL CFU CNF DER Dil Fae DL DL, RA, RE, IN DLC EDL LOO LOQ MCL MDA MDC MDL ML MPN MQL NC ND NEG POS PQL PRES QC RER RL RPO TEF TEQ TNTC These commonly used abbreviations may or may not be present in this report. Listed under the o column to designate that the result is reported on a dry weight basis Percent Recovery Contains Free Liquid Colony Forming Unit Contains No Free Liquid Duplicate Error Ratio (normalized absolute difference) Dilution Factor Detection Limit (DoD/DOE) Indicates a Dilution, Re-analysis, Re-extr action , or additional Initial metals/anion analysis of the sample Decision Level Concentration (Radiochemistry) Estimated Detection Limit (Dioxin) Limit of Detection (DoD/DOE) Limit of Quantitation (DoD/DOE) EPA recommended Maximum Contaminant Level" Minimum Detectable Activity (Radiochemistry) Minimum Detectable Concentration (Radiochemistry) Method Detection Limit Minimum Level (Dioxin) Most Probable Number Method Quantitation Limit Not Calculated Not Detected at the reporting limit (or MDL or EDL if shown) Negative / Absent Positive / Present Practical Quantitation Limit Presumptive Quality Control Relative Error Ratio (Radiochemistry) Reporting Limit or Requested Limit (Radiochemistry) Relative Percent Difference, a measure of the relative difference between two points Toxicity ECJ,1ivalent Factor (Dioxin) Toxicity ECJ,1ivalent Quotient (Dioxi n) Too Numerous To Count Job ID: 885-16446-1 11 Page 4 of 22 39 Eurofins Albuquerque 12/20/2024 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 "NETDMR-DataSheet 2024.xlsx - Dec" - Page 2 Las Vegas Wastewater Tm~ed to be ve nficd Dec 2024 (LastMonth) convcrtstoua/Lbclow A,N T K N+ Nitratc/ Date Day I S"n 2 Mon 3 T" ' 4 W,d ' Th" 6 Fri 7 Sa< 8 s"" 9 Mon IO T"' II W,d 12 Th" 13 Fri 14 Sa< 15 S"n 16 Mon 17 T"' 18 W,d 19 Th" 20 Fri 21 Sa< 22 S"n 23 Mon 24 T"' 25 Wed 26 Thur 27 Fri 28 Sa< 29 S"n JO Mon 31 T"' 30-dayMin 30-dayAvg 30-dayMax 7-dayAvg 7D av2 lbs E.Coli col Fecal Colifo r m col Alu min u m lb, Nitrate/ Cadmium l\Ier curv Amm onia, NH3 TKN TDS TP Chl orid e Nitrite asN TN m IL lbs m IL lbs m IL lbs m,IL m,IL m,IL lbs m,IL m,IL m,IL lbs 29.52 I -,-.o-o I \ I ' 15.84 4.44 0.0 18 0.018 0.062 -0.000 0.000 0.2797 0.1052 1.5254 0.00 0.00 0.00 0.00 0.00 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 -\ I \ I 24.35 \ ,.io 0.000 0.000 0.000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 Missing 4th weekly sample 0.000 0.000 0.0000 0.0000 28 .96 0.020 0.3279 0.00 0.00 0.00 0.00 0.00 - - 0.00 000 61000 0.68 16.73 76.00 13.00 ( nooo l 319.84 0.00 -30-day average needs to be the same value since there is only one sample for the month 0.00 0.00 5.21 10727 0. 187 0.00 0.00 000 0.00 0.00 0.00 6.00 62 .000 1.525 0.00 0.00 0.00 000 000 0.00 2952 "'IL lbs/dav geomean gcomcan 0.94 10.90 068 16.73 l !802 IJ - - 13.00 208.4 2 319.84 40 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 December 2024 daily flows recorded Month_).),_L_e_c._e.._1_!:i_e_--_ Daily Flows Date* Influent Flow Cont. Influent Flow Discharge Cont. Effluent Flow Cont. 2 Year 2o:2. Y UV Channel Flow Cont. 6 7 10 f 7 I ~t,~ Z.f-ib 11 'j?tt 'J}jJj'b 12 ff71 75J C,lt:,o 13 fj?J'fJJJr/,b 14 '/72.o ,ir1-z..1S"c.> 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 * Space By Word (Date) for last reading last month. Flow, in conduit or through treatment plant needs to be reported from this 41 City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Plant schematic provided 42 I,;Flv-e.,JT B~d 7S$ 13od 5eecl - \I'-'(?&-'IP I P.-ocess 7 Miss U,~esTc..,,. /1/ovTH Sou//--/ /r(C,/t-, :S-0..r>Jfle. oneea v..:<:cv, f l,, r~ ;---- ~ ~. ~ ~ !, - ; J 'VAA,Ce_ .-.?SSO I C J ia . lt i S J T- ~10LZEN-CO_@IN& A_ ._.._=_ :' -- -- -- ---- l)vy I'-") - - - - fleJ-<j i SI uJJc Z Soli'cfs : 'f 5ePr"-je 'K.ec1ev1"'j ~T..T1otJ II I y ,_ -- ,# I I - --'Cl ' I ?vocesS ;v11s s I Jf!:r1---=-=- -- 3 A6nO.T1e1N i3As1JJ AsT-;C We5/ , ~ ---1+:,b--~-----~~- L/ KAS CAST~ '\N.sT ') - --- -- - -- --- ,:i_: --- ~ EFFlueT u;~ ,,~,,~~.,f~.~:. S TR. P c. H . / STuvf>.-:,(' "- , '- ' \, East Clarifierr / , Tu.-b,d,Ty , ' D, s solv e.J ,r5e.J\J _,_ ~ ,,, K ,',<, s . ~ . ,. .~ ,,.: ... - _L', - _ I ~ T55 . -- . .. , ! / 730 !) ~ ,' scf,J f<- 5 .-~ - ~ / ,,' Ad uv c U"''" E;,ce ,-,T Ti, uR,- ,0" - PLANT SA MPUF!NGGL. RPOEI4N.3T-SJ PLAN VIEW City of Las Vegas Wastewater Treatment Plant NPDES # NM0028827 Inspection Date: 01/13/2025 Appendix 6 Follow-up on-site training and technical assistance report prepared by Robert George from Oso del Agua LLC. (OdA) on behalf of NMED GWQB. 43 Oso Del Agua LLC City of Las Vegas WWTF (DP-1118) Follow-up On-site Training and Technical Assistance Report Site Visit Date: December 4, 2024 Report Date: December 16, 2024 OVERVIEW View of the City of Las Vegas WWTF Oso del Agua LLC (OdA) has been contracted by the New Mexico Environment Department (NMED) Ground Water Quality Bureau (GWQB) to provide on-site training and technical assistance to wastewater treatment facilities throughout New Mexico to help facilities achieve and maintain compliance with their Ground Water/Liquid Waste Discharge Permits. Services are delivered at no-cost to facility owners/operators and are not related to any enforcement actions. Note that the suggestions made within this report are only recommendations, not enforceable requirements. Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) ON-SITE VISIT SUMMARY Robert George, Field Training Specialist for Oso del Agua LLC performed a follow-up on-site visit to the wastewater treatment facility (WWTF) that serves the City of Las Vegas on December 4, 2024. OdA previously visited this facility on July 27, 2022 and July 11, 2024. Reports for those visits were issued on August 5, 2022 and July 18, 2024 (respectively). Both reports should be considered as companions to this report and the July 18, 2024 report is referenced directly herein. During the recent visit, Mr. George met with the City's Wastewater Utility Superintendent Robert Espinoza, and other staff at the WWTF. Andrew Romero with the NMED GWQB also participated in the site visit. OdA spoke with Paul Kennedy from Souder Miller and Associates Operations Services and the city's Interim Utilities Director, Travis Martinez, a few days after the visit. This facility discharges reclaimed effluent pursuant to ground water Discharge Permit DP-1118, which was last renewed on January 19, 2018, and expired on January 18, 2023 (the permit continues administratively and is in the process of being renewed). DP-1118 authorizes the City to discharge up to 520,000 gallons per day (gpd) of Class 1A reclaimed domestic wastewater for sprinkler irrigation at 15 city-owned re-use locations, dispense reclaimed wastewater for temporary uses from a standpipe, and transfer reclaimed wastewater to other entities for reuse under separate Discharge Permits. Effluent is limited to 10 mg/L total nitrogen (TN). The facility also discharges to an outfall on the Gallinas River pursuant to a National Pollutant Discharge Elimination System (NPDES) permit NM0028827. The WWTF continues to suffer from the effects of the Hermits Peak/Calf Canyon Fire and from long-standing solids handling problems. The City's water treatment facility is struggling to manage the water quality that has resulted following the fire. As a result, the water treatment facility is discharging large amounts of water to the WWTF. Meanwhile, the solids handling and disposal processes at the wastewater plant continue to operate in only a limited capacity and upgrades are badly needed. Other issues related to the DP-1118 point of compliance and mechanical problems at the plant remain unresolved. OdA evaluated the treatment system and provided training/recommendations in the following areas: 1. Hydraulic Issues 2. Solids Handling 3. Point of Compliance for DP-1118 Note that while efforts have been made to make this report accessible to the general reader, the technical sections are intended primarily for knowledgeable operators, lab analysts, and engineering professionals. Not all industry acronyms are defined, and the author assumes that some of the scientific/technical concepts employed are already understood by the reader. Page 2 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) TABLE OF CONTENTS OVERVIEW.................................................................................................................................................1 ON-SITE VISIT SUMMARY.....................................................................................................................2 TABLE OF CONTENTS ............................................................................................................................3 HYDRAULIC ISSUES................................................................................................................................4 SECONDARY CLARIFIER FLOW SPLIT - .....................................................................................................4 Unwanted Overflow: .............................................................................................................................4 Blocking the Overflow: .........................................................................................................................4 Balancing the Loading to the Clarifiers: ..............................................................................................5 MANAGING THE DISCHARGES AT THE WATER PLANT - ...........................................................................5 Manage the Discharges: .......................................................................................................................5 Communicate and Coordinate:.............................................................................................................5 SOLIDS HANDLING..................................................................................................................................6 FAN-PRESS PROJECT - ...............................................................................................................................6 SOLID WASTE DISPOSAL PLAN -...............................................................................................................7 SLUDGE TRANSPORT/DISPOSAL PROBLEMS -...........................................................................................7 Sludge Loading Problem: .....................................................................................................................8 Disposal Site Sludge Spreading and Incorporation: ............................................................................9 POINT OF COMPLIANCE FOR DP-1118 ..............................................................................................9 POINT OF COMPLIANCE -...........................................................................................................................9 New Conduit/Injection Point: ...............................................................................................................9 FORMALLY REQUESTING A CHANGE TO THE POINT OF COMPLIANCE - .................................................10 CONCLUSION ..........................................................................................................................................11 SITE VISIT CONTACT INFORMATION -.......................................................................................................11 NEED FOR ADDITIONAL TRAINING - ........................................................................................................11 ACKNOWLEDGEMENT - ............................................................................................................................11 DISCLAIMER -...........................................................................................................................................11 SITE VISIT PHOTOS...............................................................................................................................12 Page 3 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) HYDRAULIC ISSUES The City's water treatment plant has been discharging larger volumes of water to the sewer system recently, causing increased turbidity in the wastewater effluent and threaten to cause a washout of the sludge blankets in the secondary clarifiers. The water plant has historically discharged filter backwash water to the sewer through a stabilizing lagoon at rates that did not pose a problem for the wastewater treatment plant. But the city installed a Veolia ballasted clarification pre-treatment unit to deal with the raw water quality following the Hermits Peak/Calf Canyon fire, and the pretreatment unit has dramatically increased the flow to the sewer. The city's WWTF typically treats around 1.0 MGD of sewage but is receiving around 120,000 gpd from the Veolia unit and has experienced additional hydraulic loads of around 0.5 - 1.0 MGD when the water plant has been forced to drain clarifiers to deal with water quality problems. While it is not possible to stop the flows altogether, there may be a few things that can be done to help mitigate the impact upon the wastewater treatment system. SECONDARY CLARIFIER FLOW SPLIT - The hydraulic loading to the secondary clarifiers is controlled at the secondary clarifier splitter box. As discussed in OdA's last report, this splitter box offers less than ideal flow control and should (ultimately) be replaced with a unit that provides more head (through higher walls), better valves, and visual feedback to the operators. But until long-term actions can be taken, the operation of the splitter box may be able to be improved. Unwanted Overflow: Currently, when the operators try to balance the flow between the east and west clarifiers, they choke down the valve feeding the east clarifier (forcing more flow to the west unit). Unfortunately, under the current high hydraulic load conditions, choking down this valve results in overflow into the abandoned rack-track aeration basin through an opening in the flow box just upstream of the splitter box. This has two negative impacts: (1) the splitter box cannot be used to evenly distribute flow to both clarifiers and (2) unwanted flow enters the abandon aeration basin, from where it must eventually be removed and returned to the treatment system (harming the treatment process). The overflow point is shown in this picture: Blocking the Overflow: This problem may be able to be addressed by installing a temporary block at this overflow point. OdA recommends constructing blocking from a piece of plywood that fits the opening mounted with a long board (2 x 4) that is cut to the proper size to allow it to be "jammed" against the opposing wall to hold the plywood blocking in place. Blocking the overflow point will increase the head in the clarifier splitter box. The additional head may be sufficient to allow the east valve to be choked down and improve the flow split. The hazard in this approach is that under very high flow conditions, the clarifier splitter box could overflow, spilling mixed liquor onto the ground. Page 4 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) To avoid this, the temporary blocking should only extend around 3 - 4 inches higher than the current water level. This way, if the water level reaches the top of the blocking, it will overflow into the abandoned aeration basin (as before) but should not overflow the splitter box. Experimentation may be necessary to arrive at the correct balance on how high the blocking can extend without creating an overflow threat at the splitter box. But getting the best hydraulic performance out of the clarifiers by balancing their loading is critical, so the effort to block the overflow should be a high priority. Balancing the Loading to the Clarifiers: Once the proper blocking is in place, a concerted effort to balance the flow to the secondary clarifiers should be undertaken. The current flow split is estimated to be around 1/3 to the west clarifier and 2/3's to the east. The east clarifier sludge blanket is only a few feet below the surface by mid-morning (and visible), confirming that the higher hydraulic load is being applied to this clarifier. If solids washout occurs, it will happen to the east clarifier first (as has historically been the case in OdA's experience). By balancing the loading closer to 50/50 between the clarifiers, they can be used to their best effect. The effluent quality should improve, and catastrophic solids washouts may be avoided. While this approach may improve the situation somewhat, a long-term effort to create a project to replace the secondary clarifier splitter box should remain a priority. MANAGING THE DISCHARGES AT THE WATER PLANT - The other area that should be addressed to mitigate the impact of the hydraulic loading problem is to ensure that everything that can be done at the City's water treatment plant is being done. Manage the Discharges: High discharge flows to the sewer have much less impact at night when other flows are low. If possible, the city should coordinate releases from the water plant to either: 1. Send the discharges to the WWTF during low flow periods (i.e., at night), or; 2. Spread the discharges over the longest period possible at the lowest flow rate possible to minimize the impact upon the WWTF. Equipment Changes at Water Plant: Doing either of these may require that new pumps or new controls be installed at the water plant, but this issue is important enough to warrant significant equipment changes/expenditure. Communicate and Coordinate: Another important area that can be improved is communication between the water and wastewater facilities. The operators of the water treatment plant should be cognizant of the potential impact of the discharges upon the WWTF and should be communicating and coordinating with the wastewater operators to minimize the impacts. OdA recommends that the city create a regular meeting once a month for the next three months where the wastewater superintendent, water treatment superintendent, and utilities director meet to discuss managing the flows and seek workable strategies. Page 5 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) SOLIDS HANDLING Continuing to reduce the solids inventory remains a primary goal for this WWTF. A description of the solids handling issues and recommendations was included in OdA's July 18, 2024 report (please refer to that report for more information). The operators have made efforts to clean out some of the sludge drying beds to create space for sludge drying, which will help somewhat, especially during the winter months. But the overall progress on addressing the solids handling problems has stalled, including on the following issues: 1. The catch-up transport of sludge to the disposal site by a contractor over the summer did not occur. This was intended to reduce the solids in the treatment system and digesters and allow the operators to take over afterward. 2. A sludge dewatering unit (fan-press) was successfully demonstrated at the facility, but only limited progress toward funding, designing, and installing the fan-press has occurred since. Installing a permanent unit is very important to meeting the long-term solids handling needs of this facility. 3. Only limited effort toward applying for a Solid Waste Disposal Plan has been made. The landfill has been contacted, but the NMED Solid Waste Bureau has not. A Disposal Plan will take at least 6 months to secure and will be needed to dispose of solids at the landfill, which is the best long-term strategy for solids disposal. It is unfortunate that the catch-up effort using a contractor to haul and apply sludge to the city's disposal site did not occur, but that is past. The fan-press was successfully demonstrated, and the city now needs to move forward on designing and funding the installation of a permanent fanpress dewatering unit. A Solid Waste Disposal Plan is also needed so that the dewatered sludge produced from the new fan-press can be disposed in the most efficient manner. Securing a disposal plan quickly will also allow the city to dispose of dried sludge that is stockpiled at the WWTF. These issues are discussed in more detail below. FAN-PRESS PROJECT - The fan-press sludge dewatering equipment project starts with the creation of an engineering scope of work (SOW) that describes the project that the city is seeking to have designed. The job of creating the SOW falls to the WWTF Superintendent and will be carried out by one of the city's on-call engineering firms. The design SOW should include the following: x Design of a sludge dewatering unit to be retro-fitted into the existing Parkson unit building. This will require the removal of the Parkson equipment, installation of a fan-press that meets the (exact) specifications of the unit that the city is seeking, plumbing, electrical, heating, lighting, and mechanical changes to accommodate the unit and its elements. The design will need to provide a method for feeding sludge to the fan-press from the digesters at a consistent rate and for transporting the dewatered sludge from the fan-press to a rolloff dumpster. The transfer method should evenly fill the dumpster while the fan-press is operational with minimal operator intervention. Page 6 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) x Suitable draft design reviews at 50%, 65% and 95% should be included to allow the facility operators to comment on the operability, maintainability, and practicality aspects of the design so that the city gets the best product possible. x Preparation of an engineer's Estimate of Probable Cost (EPC) for the equipment, installation, and construction of the project. x Preparation of construction and bid documents for the equipment, installation, and construction of the project. x Submission of the construction documents to NMED-GWQB for review and approval prior to bid. x Construction oversite of the project (unless the city seeks to hire an independent construction observer, but this person should not be associated with the contractor). x Management of the bid process (if desired by the city). x Preparation of as-built drawings at the conclusion of the project and submission of the as- builts to the city and NMED-GWQB. x Support during start-up of the equipment, including ensuring that all elements work as designed and support for any warranty claims with manufacturers. Mr. Espinoza should begin drafting the SOW for the engineering services for this project as soon as possible. In a conversation with the city's Interim Utilities Director (Travis Martinez), Mr. Martinez indicated that the funding originally intended for the replacement of the Terragator equipment can be repurposed to the fan-press project. It is unclear what this project will cost, but the EPC should help clarify this prior to bidding so the city can be prepared to fund the project. SOLID WASTE DISPOSAL PLAN - To perform landfill disposal, the City will first need to secure a Solid Waste Disposal Plan (permit) from the NMED Solid Waste Bureau. This process typically takes 6 months to a year, so it is important that the City begin the application now. To help the process, OdA provided estimates of some of the basic information for the application in its last report (see the Solids Handling section of the report dated July 18, 2024). It has been unclear who the city would seek to prepare and submit this application, but at this point, OdA recommends that this task be delegated to Josh McClenahan at the WWTF. Mr. McClenahan has done some of the preliminary work by contacting the landfill about receiving the city's sludge. Mr. McClenahan should start by contacting the NMED Solid Waste Bureau Permitting and Registration Program at 505-827-0197 or https://www.env.nm.gov/solid-waste/permittingand-registration-program/ . A complete application should be submitted as quickly as possible. SLUDGE TRANSPORT/DISPOSAL PROBLEMS - Several problems exist with the current system of transporting liquid sludge in a tanker truck to the city's sludge disposal site. The first is a recent problem with loading sludge into the truck and sludge leaking into the plant sump system. The second problem is the lack of a way to spread sludge at the disposal site and incorporate it into the soil, which are requirements of both DP-494 and the federal sludge regulations (40 CFR Part 503). These problems, and recommendation to help resolve them, are discussed below: Page 7 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) Sludge Loading Problem: A new problem has come up with loading liquid sludge from the digesters into the transport truck: insufficient head exists to move sludge into the tanker truck and sludge is being discharged back to the plant sump (where it is eventually pumped back into the treatment process). Sludge even spilled from the sump wetwell to the UV enclosure at one point, but work currently being done on the sump pumps should prevent this in the future. The issue appears to be related to the work that was done on the gravity thickener to return it to service. OdA worked with the operators to review the record drawings of the valving on the sludge lines. From that effort, an image from Molzen-Corbin's "Lime Building Modification Plan" was found: 'f ,./"J ,n,~ '<&.r<s=o=~=--i-== = = n , '1 I o/ .. 1 ~ J~t'. ,_ Uti !ii.u..t. .._....,..,.,.._,. ;:::::=~_,.,.,..,_ =.:-.:~~: - _,,. - ,... <-W ~~.==-- .. ,,_. _,. ,111~11:o--:- ... .._.............. - 1,19..Jw ..... llD!UaU< _..,...,,_.. Valves should remain closed when sludge pump is running. <W Valve should always remain closed (if found). N -.-....- This image is an overlay over an older image of the original piping (much of which is very faint). Please use the actual image (located at the treatment plant) to interpret the recommendations of this section. This image shows the valving associated with the Parkson sludge dewatering unit (now abandoned) and the "loading station pump enclosure". By tracing the piping from the digesters, it is evident that a series of valves must remain closed to avoid discharging sludge to the plant sump and generate sufficient head to load the truck. The three valves identified in the top of the image should remain closed (basically, all the time). The valve identified in the loading station pump enclosure should remain closed except when it is used to briefly drain the sludge from the loading line (to avoid spillage) after filling a tanker truck. The last valve identified (to the south of the Parkson unit building) was not found. If this valve is located, it should be kept closed. If the drawing is reflective of true conditions, keeping these valves closed should allow sludge to be transferred into the tanker truck at the normal rate and should avoid discharging sludge into the plant sump. It is possible that some of the valves were inordinately opened during the recent work performed on the sludge thickener. The valve positions should be verified and maintained in the positions suggested. Page 8 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) Disposal Site Sludge Spreading and Incorporation: Sludge transported to the city's disposal site is regulated under DP-494 and the federal sludge regulations (40 CFR Part 503). DP-494 requires that sludge be spread over the disposal site and the Part 503 requires (among other things) that sludge spread at the site be injected into the soil, incorporated into the soil, or covered with soil within a short period after being spready (typically within 6 hours or by the end of the day...See the Solids Handling section of OdA's last report for additional information). The city previously injected liquid sludge as this site using a Terragator unit, but that unit is inoperable, and repair/replacement is impractical due to cost and other factors. Sludge can still be discharged to this site, but a way must be found to spread and incorporate the sludge shortly after it is placed on the disposal site. In OdA's last report, it was recommended that the city purchase a suitable tractor and disc attachment for this task. In a conversation with Mr. Martinez after the most recent visit, he indicated that around $80,000 of funding is available now to purchase this equipment. Purchase Tractor and Discing Equipment: Recommending the purchase of this equipment is somewhat difficult, because if the city can complete the other solids handling effort (to install a fan-press and dispose of sludge to a landfill), the disposal site may not receive much use in the long-term. But without the spreading/discing equipment, the disposal site cannot be used in compliance with DP-494 and Part 503, and having the disposal site option will ensure the city has multiple sludge disposal options over the long run. Therefore, OdA recommends that the WWTF staff prepare a purchase order request for a suitable tractor and disc attachment that can spread and incorporate sludge at the disposal site. A purchase such as this will require three comparable quotes, but this type of agricultural equipment is widely available. Until this equipment is available and functional at the disposal site, sludge disposal at the site should be avoided unless another way to comply with the permit/regulations can be implemented. POINT OF COMPLIANCE FOR DP-1118 A few issues surrounding the renewal of DP-1118 should be considered by the City before NMED moves forward with drafting the renewal permit. OdA discussed these in its last report but wishes to revisit the Point of Compliance issue due to the discovery of new information. POINT OF COMPLIANCE - OdA has contended that the advantages of moving the point of compliance for DP-1118 to the discharge of the reuse tank outweigh the disadvantages. However, during the most recent visit, it became clear (to OdA for the first time) that the chlorine is being added to the effluent when it exits the effluent storage tank, not when it enters. This changes the merits of moving the point of compliance to the outlet of this tank, but OdA believes that changing the system to add chlorine as effluent enters the tank would be relatively easy to change. New Conduit/Injection Point: By installing a below ground conduit from the existing chlorine pumps to the inlet line to the tank (a distance of around 50 ft) and routing tubing Page 9 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) through the conduit, chlorine could be injected at the inlet of the tank. These photos show the locations involved: Chlorine Pumps Effluent Tank Inlet (manhole) A saddle will need to be installed in the effluent tank inlet piping (located in a manhole). The conduit will need to be routed from inside the building housing the chlorine pumps and buried deep enough to winterize the tubing conveying the chlorine solution to the injection point. The conduit should be properly sized and use only long sweep elbows to ensure that tubing can be pulled through it and replaced when necessary. FORMALLY REQUESTING A CHANGE TO THE POINT OF COMPLIANCE - Once the city determines to change the point of compliance, an amendment to the renewal application for DP-1118 should be submitted to NMED. The amendment should propose moving the point of compliance for DP-1118 and should propose an updated effluent sampling plan. Because the effluent tank greatly homogenizes the effluent water quality, NMED may be willing to accept a reduced sampling frequency. OdA recommends proposing a sampling plan as follows: Parameter Turbidity BOD E. coli Total Residual Chlorine (TRC) TKN, NO3, TDS, Cl Organic and Inorganic Compounds Monitoring Frequency Constant (process turbidimeter) 1/week, 3-hour composite sample 3/week, grab sample Grab sample collected when E. coli samples are collected 1/Quarter, grab sample(s) 1/permit term, 24-hour composite (non-flow-weighted) Notes Continuous data logging to determine monthly average and max values. Composite aliquots collected when transfers are occurring. Samples collected when transfers are occurring Samples collected when transfers are occurring Samples collected when transfers are occurring Samples collected when transfers are occurring NMED will consider the city's proposal on moving the point of compliance and altering the sampling plan. If NMED agrees, the new elements will be included in its proposed draft renewal permit. Page 10 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) CONCLUSION The City of Las Vegas WWTF continues to struggle with solids handling problems and now is dealing with high hydraulic loading issues that resulted from the Hermits Peak/Calf Canyon Fire. The city needs to do everything possible to start a project for the design of a new sludge dewatering unit and should make efforts to manage the hydraulic loads from the water treatment plant effectively. SITE VISIT CONTACT INFORMATION - Contact Name Contact Info Travis Martinez Phone: 505-617-1015 Email: tmartinez@lasvegasnm.gov Robert Espinoza Cell: 505-718-5298 Office: 505-454-3832 Email: respinoza@lasvegasnm.gov Paul Kennedy Phone: 505-231-2262 Email: paul.kennedy@soudermiller.com Alyssa Chavez Phone: 505-410-6531 Email: alyssa.chavez@smaoperations.com Josh McClenahan Phone: 505-429-7070 Email: jmcclenahan@lasvegasnm.gov Joshalyn Stromburg Phone: 505-259-7574 Email: jstromburg@lasvegasnm.gov James Lopez Phone: 505-426-6533 Email: jlopez@lasvegasnm.gov Andrew Romero Phone: 505-660-8624 Email: andrewc.romero@state.nm.us Role Utilities Director (Interim), City of Las Vegas Wastewater Superintendent, City of Las Vegas Project Manager, SMA Operations Laboratory Analyst, SMA Operations Collections Tech-1 City of Las Vegas Operator Associate City of Las Vegas Operator in Training City of Las Vegas NMED-GWQB Technical Reviewer, DP-1118 NEED FOR ADDITIONAL TRAINING - An additional visit to this site is warranted to assess progress and reevaluate the situation. Until then, OdA will remain available to the operators and City for consultation via videoconference, email, and telephone. A follow up visit will be scheduled to this facility in the 6 - 12 month timeframe. ACKNOWLEDGEMENT - Robert George wishes to sincerely thank Travis Martinez, Paul Kennedy, Robert Espinoza, and all the facility's personnel for their assistance and engagement during and after the on-site follow-up visit. DISCLAIMER - The views expressed in this report and recommendations set forth are solely the views and recommendations of Mr. George/OdA. While every effort has been made to ensure that the information contained within this report is accurate, errors and omissions can occur. If you identify an error or omission that significantly impacts the accuracy/validity of this report, please contact OdA to discuss it. If a clear error or omission has occurred, OdA will issue a revised report. Mr. George can be contacted at 1-505-901-7952 or osodelagua@icloud.com. Page 11 of 12 Oso del Agua LLC, DP-1118 City of Las Vegas WWTF Follow-up Site Visit Report (Report Date: 12/16/24) SITE VISIT PHOTOS Photo 1: East 2 Clarifier (note sludge blanket level) Photo 2: Discharge from west (left) and east (right) clarifiers Photo 3: Sludge spilled from plant sump to UV enclosure Photo 4: Drying bed nearly ready for cleaning Page 12 of 12