October 22, 2021

Freeville looks to reduce phosphorus in water

FREEVILLE — Freeville’s sewage treatment facility would need to change its phosphorus treatment plant to one based on chemicals, rather than a biological system, to meet state water quality goals for Cayuga Lake.

That’s not likely to be cheap, water quality experts said.

But the village is looking into the change, anyway, said Mayor David Fogel. Fogel said Monday he is working with wastewater technicians to learn about options to meet the state standards.

“At this point, it’s premature to talk about potential costs of phosphorus reduction at our wastewater treatment plant,” Fogel said in an email.

The Department of Environmental Conservation completed a draft April 7 calling for a 30% phosphorus reduction in Cayuga Lake. That would require the Freeville facility to reduce its phosphorus output up to 67%.

That would likely require the facility to upgrade its maintenance and operations to meet the chemical requirements, said Bruce Adams, the superintendent of wastewater for the nearby city of Cortland.

The Freeville wastewater treatment facility is an aerated lagoon, meaning it uses oxygen in the wastewater to biologically break down bacteria, Adams said. Reeds are placed to absorb the phosphorus, stripped and placed back into the water where they absorb twice their original amounts of phosphorus.

“I would think that the least expensive option for them might be chemical precipitation,” Adams said. “It would require the addition of something that would bind phosphorus and allow it to settle with the sludge.”

Chemical precipitation is a process the Cortland wastewater treatment facility uses, Adams said. Once the phosphorus has settled into the sludge, it moves through aerobic digesters and goes to the county landfill as sludge, removing the phosphorus from the facility.

“The main problem with biological phosphorus uptake is that if you, later in the process, have a low-oxygen event, the phosphorus will be re-released,” Adams said. “Even though we have installed and will be implementing biological phosphorus removal, the fact that it may release in our anaerobic digesters and be present in our filtrate in the water process could be a problem.”

Still, neither option brings financial relief, Adams said. If the Freeville facility took the chemical route, operations and regular maintenance is costly but the biological route requires investments in more equipment.

The purpose is to reduce phosphorus in Cayuga Lake, which is fed by a 785square-mile watershed that includes 120,000 people and parts of six counties: Tompkins, Cortland, Cayuga, Seneca, Schuyler, and Tioga. The lake is on the state Department of Environmental Conservation’s 303D list of impaired bodies of water that do not support appropriate uses and require phosphorus reduction.

“Cayuga Lake has been on the 303D list for quite some time, with phosphorus listed as a pollutant to the water in the south end of the lake,” said Jonathan Negley, district manager of Tompkins County Soil and Water Conservation district. “Phosphorus travels with sediment.”

The phosphorus creates a nutrient-dense body of water that leads to harmful algae blooms that affect larger plants that root in the lake, releasing cyanotoxins into the water column, creating vegetation issues and concerns for aquatic life, pets and humans, Negley said.

“We threw the question at DEC, what did the facility identified need to do?” said Shawn Murphy, natural resource conservationist with the Cortland County Soil and Water Conservation District. “The other facilities use some chemical treatment, whereas Freeville uses all biological treatments.”

Cayuga Lake is a major water supplier for five Tompkins County municipalities — Dryden, Lansing, the village of Lansing, Ithaca and Cayuga Heights and the levels of phosphorus are a concern to the drinking water source, Negley said.

“The other facilities in the watershed have already made the needed improvements to keep phosphorus output low,” Murphy said.