Document qmOQyE8N42nRnaoNrp6bE5EMj

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 5 77 WEST JACKSON BOULEVARD CHICAGO, IL 60604-3590 REPLY TO ATTENTION OF ECW-15J Andrew Berg, Mayor City of Waubun 1105 Second Ave Waubun, MN 56589 wpublicworks@arvig.net Re: Clean Water Act Compliance Evaluation Inspection Dear Mayor Berg, On August 10, 2022, the U.S. Environmental Protection Agency (EPA) conducted a compliance evaluation inspection at the Waubun Wastewater Treatment Facility (WWTF) ("Waubun" or "you") in Waubun, MN. The purpose of this inspection was to evaluate Waubun's compliance with the Clean Water Act (CWA) and its National Pollution Discharge and Elimination System (NPDES) permit. The enclosed inspection report summarizes the inspection activities and findings. No areas of concern were identified during the inspection. EPA has determined that no further information is needed at this time. If you have any questions or concerns regarding this letter or inspection report, please contact Jason Hewitt of my staff at Hewitt.Jason@epa.gov. Thank you for your cooperation. Sincerely, MOLLY SMITH Digitally signed by MOLLY SMITH Date: 2022.09.28 09:36:11 -05'00' Molly Smith Section 1 Supervisor Water Enforcement and Compliance Assurance Branch Enclosure: Inspection Report UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 5 77 WEST JACKSON BOULEVARD CHICAGO, ILLINOIS 60604 Purpose: Clean Water Act Compliance Inspection Inspection Type: National Pollutant Discharge Elimination System (NPDES) Facility: Waubun Wastewater Treatment Facility (WWTF) City of Waubun, Popple Grove Township, Mahomen County, MN S of the NE Section 25, T143N, R42W NPDES Permit Number: MN0022110 Facility Type: Wastewater Treatment Facility Date of Inspection: August 10, 2022 EPA Inspector(s): 1. Jason Hewitt, Environmental Engineer 2. Jessica Stromsdorfer, Environmental Engineer Other Attendees: 1. Brad Fleischer, City of Waubun Public Works Department Contact Email Address: Brad Fleischer, wpublicworks@arvig.net Digitally signed by JASON JASON HEWITT HEWITT EPA Lead Inspector Signature: _____________D_at_e:_202_2._09._28_09_:44_:28_-0_5'0_0'_______________ Approver Name & Title: Molly Smith, Supervisor, Section 1, Water Enforcement and Compliance Assurance Branch MOLLY Digitally signed by MOLLY SMITH Approver Signature: _S_M__IT__H_______D0_9a_:t3e6_::23_062_-20._50'90_.02_'8_________________________ Facility Notification: Unannounced Inspection Announced Inspection Regulations Relevant to Inspection: NPDES Permit requirements at 40 C.F.R. 122.26 Arrival Time: Departure Time: 10:00 AM CST 11:00 AM CST OPENING CONFERENCE Presented Credentials Stated authority and purpose of inspection Provided Small Business Resource Information Sheet Small Business Resource Information Sheet not provided. Reason: Not a small business Provided CBI warning to facility The following information was obtained through review of the Facility NPDES Permit, and verbally from Representatives of the Waubun WWTF, unless otherwise noted. Process Description: The existing treatment system consists of one lift station, approximately 3,375 feet of six-inch force main, one pump station, two primary cells lined with a synthetic liner, with a surface area of 3.85 acres, and a secondary cell lined with a synthetic liner, with a surface area of 3.86 acres. The treatment system is designed to treat an average wet weather flow of 71,650 gallons per day (gpd) and provide a total detention time of 210 days at design flow. The Facility has a controlled discharge to County Ditch No. 3, which leads to Spring Creek. The Facility is required to sample prior to discharging, if all effluent limits are met, the facility may discharge. Acceptable discharge periods are March 1 through June 30 and September 1 through December 31. However, the permittee may discharge outside the period if they notify the permitting and regulatory authority for approval, and there is an adequate dilution ratio. Pre discharge sampling shall be conducted as a composite sample, taken at each corner of the treatment cell. Staff Interview(s): The following information was obtained during the opening conference, led by EPA. When staff arrived, they were met by Brad Fleischer, who informed them that the WWTF lagoons had raised to the top of their freeboard and the Facility began emergency discharging a few days prior. The Facility notified MPCA via phone on August 8, 2022 that they were close to experiencing cell overflow. MPCA advised an emergency continuous discharge until the freeboard was back to 3 feet. 2 MPCA also advised sampling, as soon as possible, to ensure that the discharge was not exceeding limits. The operator sampled after opening the discharge valve on August 8, 2022. Effluent numbers were exceedingly low. The operator believed heavy flows to the WWTF caused by rain and sump pumps resulted in high dilution. The operator informed EPA that all town sump pumps were plumbed directly to sanitary, and after abnormally high summer rains the system was not able to assimilate the heavy flows. At the time of the inspection, freeboard was approximately 1 foot. Typically, influent flow is about 1 million gallons (MG) per month. In the month prior to the inspection, influent flow was measured at 4.6 MG at the lifts, causing freeboard to reduce from 4' to 0', which has not happened in past years. The previous facility did not experience this since the clay liners usually leaked enough to discharge within the old ponds. Spring of 2022 was the first discharge on the newly constructed system. Prior to discharge, the lagoons sat for almost 8 months, close to detention time, but since the Facility was recently constructed, the operator had hoped to allow the system to sit longer to reach optimal conditions. Due to the new nature of the Facility, no sludge has been removed yet. Construction began in 2019 wherein they removed the old ponds, contracted local farms to haul the solids, and constructed the new cells on adjacent land. Additionally, the force main was rerouted during construction of the new system. The operator noted that during regular flow, the lift stations run on average for 30 minutes a day, however during the heavy summer rains, they have been in operation for 3.5 to 4 hours a day. The lift stations pump approximately 290 gallons per minute and are brand new. The user base for the WWTF is 162 commercial and residential connections, no industrial. The lagoon has had nuisance animals including otters, mink, deer, and pheasants. The operator does remove nuisance animals when able, especially if burrow holes are noticed. There has been no evidence of animal damage to the liners. The operator samples at four sides of the secondary pond and does the testing in situ using a calibrated probe and plastic bottles to capture the sample. If the probe measurement shows in range, the operator then takes the sample to R&B Labs, west of the city, for further testing and verification. If the probe samples out of range, no further actions are taken as the operator notes, in that instance the Facility cannot discharge. Influent samples are taken at the lift station, which is where the calibration of the probe is typically performed. Effluent sampling is taken at the outfall, as opposed to the structure, for safety reasons. Facility Walk-Through Occurred: Yes Data Collected and Observations: The following are observations made by the EPA inspectors and information shared by the Facility during a tour of the Facility: 1. The lagoon ponds were below permitted freeboard due to heavy rains, but operator contacted MPCA to begin recent emergency discharging and sampling after the fact. At the time of 3 inspection, Facility was still discharging to reach 3' of freeboard. Discharge was free of any color, odor, or other visual indicators of pollutants. 2. At the time of the inspection, sampling procedures were being followed. Verification was made that the probe is calibrated by the operator in the morning, as other local facilities (Ogema WWTF) share the probe in the afternoon. 3. At the time of the inspection, inspectors did not see evidence of any damage to liners from equipment or nuisance animals. 4. WWTF had very low/no odor, which is to be expected for new lagoon system in proper operation. Photos and/or Videos: were taken during the inspection. Included as Attachment A. Field Measurements: were not taken during this inspection. RECORDS REVIEW - NOT CONDUCTED ON SITE CLOSING CONFERENCE Provided U.S. EPA point of contact to the facility Confirm CBI status at end of closing conference Requested documents: None Areas of Concern: No Areas of Concern Identified APPENDICES AND ATTACHMENTS ATTACHMENT A: PHOTO LOG 4 Waubun WWTF EPA Inspection August 10, 2022 All photos taken by Jessica Stromsdorfer, Environmental Engineer, U.S. EPA Camera: Optio WG-1 GPS Ver 1.00 1: P8100025 Description: Primary Treatment Cell #1 Location: Waubun WWTF Camera Direction: NE Date/Time: August 10, 2022 Page 1 Waubun WWTF August 10, 2022 2: P8100026 Description: Primary Treatment Cell #1 Location: Waubun WWTF Camera Direction: E Date/Time: August 10, 2022 3: P8100027 Description: Primary Treatment Cell #2 Location: Waubun WWTF Camera Direction: SE Date/Time: August 10, 2022 Page 2 Waubun WWTF August 10, 2022 4: P8100028 Description: Secondary Treatment Cell Location: Waubun WWTF Camera Direction: NE Date/Time: August 10, 2022 5: P8100029 Description: Secondary Treatment Cell Location: Waubun WWTF Camera Direction: N Date/Time: August 10, 2022 Page 3 Waubun WWTF August 10, 2022 6: P8100030 Description: Discharge Valve and Outfall Location: Waubun WWTF Camera Direction: E Date/Time: August 10, 2022 7: P8100031 Description: Discharge Sample Location Location: Waubun WWTF Camera Direction: NE Date/Time: August 10, 2022 Page 4 Waubun WWTF August 10, 2022 8: P8100032 Description: Primary Treatment Cell #2 Location: Waubun WWTF Camera Direction: W Date/Time: August 10, 2022 9: P8100033 Description: Influent Chamber and Weir Location: Waubun WWTF Camera Direction: Down Date/Time: August 10, 2022 Page 5 Waubun WWTF August 10, 2022