Saturday, April 3rd, 2021
Pilot study ongoing
Aim is to reduce phosphorus in lake
By William Kincaid
MONTEZUMA - Montezuma Club Island wastewater treatment plant officials are moving onto the next phase of a pilot study of an onsite vegetative biofilter designed to provide an extra safeguard against phosphorous loading into Grand Lake.
The study is the first of its kind in Ohio.
The aim of the biofilter is to reduce the pollutants to a level where the Ohio Environmental Protection Agency would allow plant officials to discharge treated water during summer months. Current permit restraints on discharge times require officials to have ample storage to hold the treated waters between May 30 to Oct. 31, according to county sanitary director Kent Hinton.
Hinton and county community development director Jared Ebbing this week updated county commissioners on the pilot study.
"Right now our plant, we can only discharge in the non-summer months because (OEPA) didn't want us to discharge during the summer months just straight into the creek and then straight to the lake," Ebbing said. "This allows us to continuously have a flow in those summer months - May, June, July, August."
The benefits of the process would be various.
"It just literally opens another window for us to discharge," Ebbing said. "(There would be) less burden in the winter months to have to open up the valve and let a whole bunch of water through at one time. Do you want a major flush or do you want a small trickle throughout the year?"
Officials can only discharge when water is flowing in the creek. This is to prevent a heavy buildup of pollutants in stagnant waters.
"With the EPA, they look at streamflow," Hinton said. "When you need to do a major flush, if the stream flow is not there, they don't want you to discharge anything, even though it's good water."
Also, county officials, if authorized to release limited amounts of treated wastewater in the summer, could hold off on having to build a multimillion dollar fifth lagoon for 20 to 30 years, Hinton said.
OEPA on Jan. 18, 2017, authorized a three-year study of the biofilter, Hinton said. The plant is along Guadalupe Road in Franklin Township and services more than 2,000 residential and commercial customers on the south side of Montezuma from Johnson Road near Coldwater Creek to past Behm Road.
The plant has four lagoons, two for treatment and two for polishing/holding. After initial treatment, the water flows into a polishing lagoon where any remaining substances are eradicated and oxygen levels increase, Hinton said.
Typically the plant discharges water from the polishing lagoon into a tributary that drains into Beaver Creek.
Plant employees created a six-acre vegetative biofilter on a strip of land that is similar in concept to treatment trains installed around Grand Lake since 2012. Treatment trains divert a portion of the creeks' water into a series of wetland cells containing plants that remove some nutrients before the cleaner water is released into the lake.
Plant employees moved and compacted dirt and built an embankment on six ares of county land used as a buffer zone between the lagoons and Cassella-Montezuma Road. They then planted a blend of seeds provided by the Ohio Department of Natural Resources that were leftover from a treatment train, Hinton said.
During the first three years of the pilot study, treated water was pumped from the third lagoon into the biofilter to naturally remove phosphorous. Phosphorous is the favorite food source of toxic blue-green algae that has prompted a recreational no-contact order on Grand Lake since July 30, 2015.
OEPA set a phosphorous discharge limit of 1.5 milligrams per liter at the plant, but the treated water has tested well below that figure, anywhere from 0.2 to 0.85 milligrams per liter, according to Hinton's records.
When run through the extra step of the biofilter, though, the level of phosphorous is undetectable, proving the additional layer of organic treatment works, Hinton has said.
However, OEPA has requested a modification to the process that includes ensuring a a more continuous discharge of treated water through the biofilter and testing the biofilter for two more years until 2022. The pilot test started in 2018.
"Basically, (OEPA's) saying in order for us to meet the next two summer's worth of testing, we've got to have continuous flow out there rather than just periodically pumping it in," Ebbing said.
County officials must install up to 500 feet of pipe from the third lagoon to the biofilter.
"We did intermittent (pumping) the last couple summers - a little bit here, a little bit there," Ebbing said. "Now it's going to be, you open the valve and it's continuous 100,000 gallons every day going through that wetland. We'll determine the test results and see how it does."
Ebbing said the pipe would be installed in the coming weeks. He estimates it will cost up to $50,000.
Hinton hopes OEPA will permit the plant to discharge treated water during the summer, perhaps as much as 125,000 gallons a day. During the winter, the plant discharges an average of 1.42 million gallons a day when the water is flowing in Beaver Creek. If the OEPA allows the plant to discharge the treated water during the summer, it would not be necessary to add a costly fifth lagoon to accommodate future growth at the plant.
County commissioners in 2011 acquired a $1.14 million Water Pollution Control loan to construct a fourth lagoon and install aerators in two lagoons at the plant.
"That's an exciting project out there," commissioner Rick Muhlenkamp said. "It's probably unique to the state even, isn't it?"
It is indeed, Ebbing replied.
"It's something that isn't normally done because not a lot of places have that kind of land availability to build a wetland on the outside of their wastewater plant," he said. "Hopefully it's something that can be looked at and replicated across other parts in the county or across the state."
Also, looking down the road, Hinton said he would like to install another vegetative biofilter on a nearby 12-acre site. Under a best case scenario, the second biofilter would allow for full evaporation of treated water during hot dry times, leading to "zero discharge in Grand Lake," according to Hinton.