LAWTON – City officials have spent the last three years coping with myriad problems at the 47-year-old municipal wastewater treatment plant that have led to a series of health and environmental infractions.
Most recently, the state Department of Environmental Quality issued another Notice of Violation to the City of Lawton on July 30.
That was prompted by a citizen complaint about a fish kill discovered July 7 in East Cache Creek at Sultan Park in Walters “roughly 25 stream miles downstream” of the point where treated effluent from the WWTP enters Nine Mile Creek south of Lawton through a discharge pipe.
DEQ Environmental Programs Specialists Greg Ressel and Jeff Lawler said they counted 20 dead fish between Sultan Park and the confluence of Nine Mile Creek with East Cache Creek, which in turn empties into the Red River.
Ressel said he investigated “the complaint site” and measured ammonia and dissolved oxygen concentrations where the dead fish were discovered. Ressel also said he inspected the site two days earlier “and found that the water in [East Cache] Creek was black.” However, subsequent heavy rainfall “washed significant amounts of sediment downstream,” which changed the color of the water to “an opaque brown.”
A DEQ review of the Lawton WWTP’s process control data from June 22 to July 8 showed that the effluent ammonia concentration was in a range “3-5 times the ammonia toxicity concentration for fish.”
However, at the time of the reported fish deaths, ammonia at the sample site tested by the DEQ was “within compliance of the WWTP effluent permit parameters,” wrote David Hastings, Lawton’s wastewater treatment plant superintendent.
Hastings also noted that on Independence Day a storm with “extreme temperatures” passed through the Lawton area and dumped 1.9 inches of rain within 45 minutes, causing “a rapid increase in flow and level of East Cache Creek … and just as quickly a rapid decrease in flow and level” in the creek.
The storm “caused localized flooding but the water receded very rapidly,” he recalled. As the flow receded “there were many pools that were left with shallow water.” Fish swimming from deeper pools when the water level rose “were stranded in the shallow holes” and became trapped as the water receded, he related.
“The excess water temperatures due to the over-100 degrees air temperatures, and the larger fish in the shallow waters, were major contributors to the fish deaths,” Hastings wrote.
Dam gates raised to send water to Walters Sultan Park near Walters requested additional water in East Cache Creek on July 10 “due to extremely low levels.” An event was scheduled at the park July 22-26 and they needed to pump water from East Cache Creek to Sultan Park “to bring it to normal levels due to several feet of evaporation.”
In order to raise the level of East Cache Creek “to aid activities at Sultan Park and allow fish trapped in the shallow pools to move to deeper waters,” the City of Lawton opened two gates at the Lake Ellsworth spillway, by 4 inches each, from July 12 through July 30, according to Lawton Lakes Superintendent Jim Bonnarens.
Enough water was flowing in East Cache Creek for a pump to transfer water from East Cache Creek approximately 120 feet to Sultan Park on July 14-16.
Others contribute to WWTP problems The City of Lawton received reports of bypasses of raw, untreated sewage from the GEO Group prison entering downstream of the Lawton WWTP’s discharge point into Nine Mile Creek. More than 1,000 convicts are incarcerated in the private prison southeast of Lawton. Those overruns were reported Aug. 7 to the DEQ, which was advised the problem had been ongoing for several months.
Similarly, one of Lawton’s “significant industrial users,” Republic Paperboard, has experienced failures at its pre-treatment WWTP, Lawton Public Utilities Director Rusty Whisenhunt wrote to DEQ District Engineer David Mercer in May.
Consequently, the biochemical oxygen demand concentration at Lawton’s WWTP “has been more than four times the permitted concentration typically received” from Republic. The DEQ issued a NOV to Republic Paperboard on Oct. 31, 2023, for exceeding biochemical oxygen demand and total suspended solids “from Oct. 17, 2023, onward.”
The City of Lawton sent a letter to Republic on Dec. 7, 2023, stating that the NOV would “remain open until consistent compliance has been achieved.” BOD results for the last seven months have been elevated.
Republic’s BOD results from mid-October 2023 to April 2024 averaged over 2,675 milligrams per liter, the city reported. The maximum permissible limit is 993 mg/L, city officials said, adding that compliance “is still not achieved” as of Aug. 22.
Another problem, according to a city report, is that sludge from Lawton’s Southeast Water Treatment Plant is causing “overloading” at the wastewater treatment plant, which is at 8104 SE 15th St. between Gooden Road and Tinney Road.
Now in compliance, WWTP supt. reports Mercer called Whisenhunt on July 26 and informed him the city would have 15 days to “eliminate and prevent recurrence of the violations…” Hastings responded in an Aug. 13 letter to Shellie R. Chard, director of DEQ’s Water Quality Division, that the sewage treatment plant “reached full compliance” with its Oklahoma Pollutant Discharge Elimination System permit on July 27 – the day after Mercer called Whisenhunt and three days before the DEQ sent Lawton Mayor Stan Booker the latest Notice of Violation.
Additional improvements are underway at Lawton’s sewage treatment plant, but the facility is “currently discharging effluent that meets all regulatory standards,” Hastings wrote. Also, the City of Lawton “remains committed to maintaining this level of compliance and ensuring the WWTP continues to operate effectively as the construction project continues.”
Reseeding of the aeration basins was completed on July 26. “This also enhanced the ability for the downstream nitrification clarifiers to settle appropriately and improve the effluent total suspended solids, biochemical oxygen demand, and ammonia removal,” Hastings reported.
The clarity of the treated wastewater “has also improved the ease of disinfection for E. coli, which is back in compliance,” he said. Phase 1 improvements will cost about $100M Phase 1 improvements to the WWTP and the design of Phase 2 collectively will total approximately $100 million, city officials told Southwest Ledger.
During Phase 1 primary clarifiers 2 and 4 were drained and cleaned, and their “rake assemblies” were reinforced, Hastings said. A rake assembly on a clarifier conveys settled sludge to a sump, where it can be removed, and a surface skimmer to remove any floating debris called “scum”.
Primary clarifier No. 1 was drained this month for cleaning, debris removal, inspection, and potential reinforcement of the rake assembly. Grit was removed and hauled to the landfill.
“This process ensures downstream primary clarifiers will remain free of grit, which can inhibit rake assembly and pumping capabilities from primary clarifiers,” Hastings said.
Also in Phase 1, trickling filters 2 and 4 were taken offline and overhauled, and trickling filters 1 and 3 are undergoing renovations now, he indicated. A trickling filter is a type of sewage treatment system that uses microorganisms to remove organic matter from wastewater.
Because of their “age and obsolescence of equipment,” the trickling filters “struggled” to perform adequately, Whisenhunt informed Mercer in May. “When operating effectively, these trickling filters reduce biochemical oxygen demand upstream of the aeration basin,” Whisenhunt wrote. But their “reduced performance compounded the issues experienced with the blower failure in the aeration basin.”
Replacement of multiple aeration basin blowers is another project in Phase 1. The existing units are obsolete and no longer are reliably serviced by the manufacturer, Whisenhunt told Mercer.
Consequently, two rental units have been acquired, “each capable of sustaining the oxygen needs of the wastewater treatment process,” Hastings reported. Those blowers cost the city approximately $38,000 per month, he said.
In addition, “We have expedited a project to replace the three inoperable blowers with four permanent blowers” that will provide “adequate redundancy.” That will cost $1.56 million, he said.
The renovations are being financed with a pair of Clean Water State Revolving Fund loans of $47 million and $72.9 million issued to the Lawton Water Authority, Whisenhunt informed the City Council.
City officials asked the state Department of Environmental Quality for an extension to complete the Phase I projects, which would result in a new completion date in August 2025.
Phase 2 in design Phase 2 of the WWTP rehabilitation project is in the design stage, Whisenhunt wrote in his May 13 letter to the DEQ.
Phase 2 of the treatment plant overhaul will cost approximately $80 million, according to Whisenhunt: UV (ultraviolet light) disinfection, $20 million; and solids handling and digester replacement, $60 million.
The Phase 2 design will take Garver engineers approximately 15 months to complete, Whisenhunt informed the Lawton Water Authority on May 14. 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, he said Lawton investing millions in WWTP, sewer lines The City of Lawton is investing approximately $200 million to renovate its malfunctioning wastewater treatment plant and replace dilapidated sanitary sewer lines. Lawton’s sewage collection and treatment system has been a repeat offender of unauthorized releases of wastewater for almost three decades.
The DEQ issued notices of violations or consent orders against the City of Lawton because of its wastewater collection and treatment systems in 2000, 2003, 2011, 2013, 2019 (twice), 2021, and twice in 2024, Ledger inquiries to the DEQ indicated.