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LSASD Project ID: 24-0107 Murrells Inlet WWTP NPDES Compliance Evaluation Inspection 1441 Pond Rd. Murrells Inlet, SC Project Date(s): July 23rd, 2024 Report Date: September 23rd, 2024 FSBFORM-1403-R0 073024 Project Leader: Chris McHugh Water Quality Section Field Services Branch Laboratory Services & Applied Science Division USEPA - Region 4 980 College Station Road Athens, Georgia 30605-2720 LSASD Project ID: 24-0107 Page 1 of 8 Final Report FSBFORM-1403-R0 073024 Project Requestor: Jairo Castillo, P.E. Section Chief Wastewater Enforcement Section Enforcement and Compliance Assurance Division U.S. Environmental Protection Agency 61 Forsyth Street, SW Atlanta, GA 30303 404.562.9756 (office) Analytical Support: NA Approvals: CHRISTOPHER MCHUGH Chris McHugh, Inspector Water Quality Section Field Services Branch Digitally signed by CHRISTOPHER MCHUGH Date: 2024.09.23 10:35:29 -04'00' Date Approving Officials: JOEL OWEN Joel Owen, Technical Reviewer Water Quality Section Field Services Branch Digitally signed by JOEL OWEN Date: 2024.09.23 10:57:03 -04'00' Date GREGORY WHITE Greg White, Supervisor Water Quality Section Field Services Branch Digitally signed by GREGORY WHITE Date: 2024.09.23 12:16:04 -04'00' Date JAIRO CASTILLO Jairo Castillo, P.E., Supervisor Wastewater Enforcement Section Water Enforcement Branch Digitally signed by JAIRO CASTILLO Date: 2024.09.23 12:29:07 -04'00' Date LSASD Project ID: 24-0107 Page 2 of 8 Final Report FSBFORM-1403-R0 073024 1. Introduction On July 23rd, 2024, staff of the United States Environmental Protection Agency (EPA) Region 4, Laboratory Services and Applied Science Division (LSASD), conducted a National Pollutant Discharge Elimination System (NPDES) Compliance Evaluation Inspection (CEI) at Murrells Inlet WWTP in Murrells Inlet, South Carolina. The inspection was conducted under the authority of Section 308 of the Clean Water Act (CWA), as amended, and followed the procedures listed in the LSASD Project No. 24 - 0107 Sample and Analysis Plan (SAP). This report presents the results of the inspection. Table 1 lists the sampling participants and facility staff. Table 1 - Inspection Personnel Name Asher Sampong Chris McHugh Organization EPA Region 4 LSASD Inspection EPA Region 4 LSASD Inspection Date on Site 07/23/2024 07/23/2024 Contact Info sampong.asher@epa.gov mchugh.christopher@epa.gov 2. Inspection Procedures The objective of this inspection was to evaluate the condition of the WWTP and the permittee's self-monitoring program and offer compliance assistance as needed. Specific tasks included conducting an opening conference, interviewing facility staff, conducting a facility walkthrough, conducting records review, observing the receiving waters, and conducting a closing conference. 3. Facility Description Murrells Inlet WWTP treatment system includes two identical systems of mechanical bar screens, oxidation ditches, secondary clarifiers, and chlorine contact chambers with four feet wide rectangular weirs to measure effluent flow (see Figure 1). Waste sludge is sent via tanker truck to Pawley's Island WWTP for disposal. LSASD Project ID: 24-0107 Page 3 of 8 Final Report FSBFORM-1403-R0 073024 4. NPDES Permit Figure 1 - Facility Aerial View The facility's National Pollutant Discharge Elimination (NPDES) permit number SC0040959 was issued (renewed) by the State of South Carolina on March 1st, 2024, and expires on November 30, 2026. The NPDES permits Murrell's Inlet WWTP to discharge an average of two million gallons per day (MGD) of treated wastewater through Outfall 001 to the Waccamaw River. The permit includes effluent limits for Total Suspended Solids (TSS), 5-day Biochemical Oxygen Demand (BOD5), Total Phosphorous, pH, Dissolved Oxygen (DO), Total Ammonia Nitrogen, Mercury, Total Residual Chlorine, and E. coli. 5. Records and Reports I. Discharge Monitoring Reports (DMR) Review The facility has failure to report DMR from 04/01/22 - 06/30/23 listed on the EPA Enforcement and Compliance History Online (ECHO) database. The current operator did not have information regarding previous facility operator's potential reporting mistakes. LSASD Project ID: 24-0107 Page 4 of 8 Final Report FSBFORM-1403-R0 073024 II. Records Review The facility maintains all its discharge monitoring reports and analytical records onsite and had at least 3 years of DMR records and 5 years of sludge records available. It is not clear as to why the past years DMRs from 04/01/22 to 06/30/23 were not reported to the EPA's Integrated Compliance Information System (ICIS). III. Flow Measurement The facility uses a 4ft rectangular weir and ultrasonic flow meter to measure and record effluent flow rate for the two effluent discharge channels from the parallel chlorine contact chambers. Both ultrasonic flow meters were last calibrated in May 2024. An instantaneous flow check was conducted on one of the flow meters, and the secondary flow rate reading was 3% different from the primary flow rate, which is within the recommended 10% difference for adequate accuracy, as referenced by the 2017 EPA NPDES Compliance Inspection Manual. IV. Sampling Review The facility collects and analyzes 24-hr time-based composite samples for its permit listed parameters as specified in the NPDES Permit SC0040959 and are analyzed by Murrell's Inlet Drinking Water Treatment Facility. Low level Mercury testing is handled via nearby contract laboratory. Sample Chain of Custodies were filled out completely and contained sufficient sample collection documentation per the 2017 NPDES Compliance Inspectional Manual guidelines: (https://www.epa.gov/sites/default/files/2017-03/documents/npdesinspect-appendix-am.pdf). 6. Operation and Maintenance The facility is operating and working to maintain its treatment units to meet its NPDES permit requirements. At the time of the inspection, the grit chamber was not operational, and the facility stated that it is waiting for a new pump to repair the unit. There was some amount of grit seen in both oxidation ditches (Figure 2) and secondary clarifiers (Figure 3). Additionally, the secondary clarifiers had a lot of algae growth on the weir plates (Figure 3). LSASD Project ID: 24-0107 Page 5 of 8 Final Report FSBFORM-1403-R0 073024 Figure 2 - Grit presence in Oxidation Ditch LSASD Project ID: 24-0107 Page 6 of 8 Final Report FSBFORM-1403-R0 073024 Figure 3 - Presence of Grit in Clarifier and Algae Growth on Weir Plates 7. Effluent and Receiving Waters The effluent discharge was clear and free of any excessive foam in the receiving stream. 8. Discussions and Findings The following are recommendations based on the inspection: Facility should immediately repair the grit system to avoid grit impacts in their treatment processes, including but not limited to, accumulation of grit in tanks that LSASD Project ID: 24-0107 Page 7 of 8 Final Report FSBFORM-1403-R0 073024 reduce treatment capacity, clogs in pipes and channels, and wear and tear on pumps, valves, and other equipment. Facility should upload the missing DMR data to the SC Department of Environmental Services (SCDES) electronic DMR system and/or consult with the SCDES to identify any potential data transfer issues. Facility should perform more routine cleaning to prevent excessive algae growth on secondary clarifier weir plates, which can lead to poor effluent water quality. End of Report LSASD Project ID: 24-0107 Page 8 of 8 Final Report