LAWTON – The state Department of Environmental Quality issued another Notice of Violations to the City of Lawton earlier this month because the agency “was not aware of the full extent of the additional problems Lawton was experiencing” with its troubled wastewater treatment plant.
Mayor Stan Booker and Public Utilities Director Rusty Whisenhunt were officially informed of the Notice of Violation in a Nov. 15 letter from Shellie R. Chard, director of the DEQ’s Water Quality Division. Problems cited were “operation and maintenance violations” and “24-hour reporting violations.”
The DEQ issued a Notice of Violation (NOV) to the municipal wastewater treatment plant (WWTP) stemming from a complaint received 11 months ago, in January 2024, “regarding conditions in Nine Mile Creek,” a press release from City Hall related.
Lawton’s sewage treatment plant discharges treated wastewater into Nine Mile Creek, which merges with East Cache Creek, which in turn empties into the Red River. The discharge rate from the WWTP is “anywhere from 14 million to 16 million gallons per day,” the city’s communications manager, Caitlin Gatlin, told Southwest Ledger.
According to the NOV, the City of Lawton was cited for inoperable grit removal basins, aeration system failures, and excessive sludge accumulation in primary clarifiers, which impacted effluent quality from January to July 2024.
City Hall is required to respond within 30 days of receipt of the document.
“These issues have already been addressed” under a consent decree the city signed with DEQ in 2020, Gatlin said.
The City of Lawton “has made significant upgrades to the WWTP since the initial complaint in January and has been in full compliance since July 26” of this year, she wrote.
The four primary clarifiers “are being cleared of excessive sludge routinely and returned to service.” A “comprehensive rehabilitation project” is underway to “replace the influent pump station, coarse and fine screening, solids handling upgrade, and controls” as part of the city’s $175 million renovation project at the sewage treatment plant.
While slated for replacement, the grit removal basins “are currently being cleaned manually to maintain operations,” she said. New grit removal basins are under construction and are scheduled to start up in late March or April 2025, Gatlin said.
David Hastings, manager of the WWTP, informed DEQ District Engineer David Mercer on Jan. 23, 2024, that two of the three blowers for the aeration process had failed, leaving only the smaller blower operational. Parts were cannibalized from the smaller blower to the larger units and they were operating – but at only 60% of their capacity, which was less than needed to supply the activated sludge treatment process.
Consequently, the city rented two blowers – “one operational and one for standby” – that were “capable of sustaining the oxygen needs of the treatment process,” Hastings said. The city is paying approximately $38,000 per month to rent those two units, Gatlin said. “We have expedited a project to replace our three inoperable blowers with four new, permanent blowers with adequate redundancy,” at a cost of $1,565,419, Gatlin added.
The temporary aeration basin blower rental units remain on-site. The new blowers have been ordered and are scheduled to be delivered “and we are aiming for the May/June 2025 time frame to have those operational,” Gatlin said. DEQ NOV cites ‘improper reporting’ The city was cited by the DEQ for improper reporting of those issues to the agency in January.
WWTP performance, including compliance issues, “are reported every month with the plant Discharge Monitoring Report to DEQ,” Gatlin noted. The monthly wastewater discharge monitoring reports are to include effluent monitoring results for ammonia, biochemical oxygen demand, E. coli bacteria concentrations, total residual chlorine, and total suspended solids sampling.
Additionally, the city has shared “daily lab results from plant compliance with both local and state DEQ offices” since July, Gatlin said.
The NOV “acknowledges past difficulties but also highlights the city’s corrective actions,” which have been communicated to DEQ, she said. Ongoing improvements to the WWTP “demonstrate the city’s dedication to sustaining full compliance, protecting public health and the environment,” she said.
The City of Lawton “has been working … over the past three years” to correct “issues” with the 47-year-old wastewater treatment plant, Public Utilities Director Whisenhunt wrote in a May 13 letter to DEQ’s Water Quality Division.
Those measures included an equipment replacement project that was completed in November 2022 and a construction project currently underway, he said.
Phase I renovations that will cost an estimated $85 million started in 2022 and are on track for completion by summer 2025, Whisenhunt reported. The renovations are being financed with a pair of Clean Water State Revolving Fund (CWSRF) loans of $47 million and $72.9 million issued to the Lawton Water Authority, Whisenhunt told the City Council.
Phase II, which is in design, is expected to be ready for construction advertisement by July 2025, he said. The design work is being financed “in large part” from a $6 million Federal Communities Grant received last year, and remaining funds available through a CWSRF loan obtained in 2022, Whisenhunt said.
Phase II of the treatment plant overhaul will cost approximately $90 million and “aims to expand solids handling, UV (ultraviolet light) disinfection, and sludge digestion,” Whisenhunt wrote in his May 13 letter to the DEQ.
Aged WWTP blamed for many infractions Lawton’s wastewater treatment plant went into service in 1977, records reflect. Because of the facility’s age, “Many key processes have exceeded the design life of the equipment,” the city’s former communications director told the Ledger in 2021.
The municipal wastewater collection and treatment system has been on the DEQ’s radar screen for two decades. The sewage treatment plant has received four Notices of Violations (one in 2019 and three this year) and at least two consent decrees (the first in 2003 and another in 2021).
In an NOV issued April 18, the city was cited for 19 infractions that occurred between December 2023 and February 2024.
Those violations involved ammonia concentrations, carbonaceous biochemical oxygen demand (CBOD), total suspended solids, and dissolved oxygen. Ammonia concentrations were three to five times allowable limits; CBOD, as much as five and seven times greater than permissible limits; total suspended solids, almost 10 times higher than acceptable limits.
The Nov. 15 notice “is a culmination of ongoing discussions between DEQ and Lawton since events early in 2024,” Erin Hatfield, director of DEQ’s Office of Communications and Education, told Southwest Ledger on Nov. 20.
The state environmental agency “was not aware of the full extent of the additional problems Lawton was experiencing with the plant until in-depth discussions on the matter during the investigation of numerous citizen complaints about the plant’s effluent and its effect on the receiving stream, earlier in the year,” Hatfield wrote in an email.
“Had DEQ been fully aware of the details at the time the previous NOVs were issued, those violations would have been cited then. This new NOV will complete the record of the events of this year.”
The city’s engineering report dated June 2021 “shows that the WWTP’s two grit removal basins had been inoperable” for five years, since 2016, “and that the four primary clarifiers contained an excessive accumulation of sludge,” the DEQ’s Nov. 15 letter to Booker and Whisenhunt related.
In January 2022 DEQ received “a progress report” from the City of Lawton “which indicated that while the primary clarifiers were being drained, cleaned, and inspected” as part of an Immediate Corrective Action Plan, “it became evident that more extensive replacement of major components, such as the scraper drive units, was necessary,” Shellie Chard, director of DEQ’s Water Quality Division, wrote in that letter.
DEQ received notice in November 2022 that the city completed its Immediate Corrective Action Plan (CAP), which included rehabilitation of the primary clarifiers.
In January 2024 the City of Lawton notified DEQ that several aeration basin blowers at the WWTP “became inoperable,” Chard continued. That “began a period” that lasted until late July 2024 “in which the WWTP was not providing complete wastewater treatment, specifically lacking effective secondary (biological) treatment,” she wrote in her letter.
In addition, the city indicated in ongoing correspondence with DEQ that the primary clarifiers had accumulated excessive amounts of grit and solids” which made the primary clarifiers “inoperable and needing similar improvements that were included as part of the Immediate CAP.”
Consequently, the inoperability of the primary clarifiers “added to the difficulty of re-establishing healthy activated sludge in the secondary wastewater treatment system and producing fully treated effluent,” Chard continued. The process of restoring the primary clarification process “continued into at least June 2024.”
CO ‘does not absolve Lawton of responsibility’ “It is true that the Consent Order addresses permit limit violations and effluent quality from Lawton’s wastewater treatment plant,” Hatfield wrote. “However, it does not absolve Lawton of the responsibility to operate and maintain the plant to the best of its ability, including reporting plant upsets to DEQ, while permanent improvements are being implemented.”
“We have been diligently corresponding with the DEQ to keep them apprised of the operational status of the wastewater treatment plant and will continue to do so,” City Manager John Ratliff told the Ledger on Nov. 22.