ORONO, Maine — You can make all the improvements you want to a wastewater treatment facility, but you’ll never get rid of that distinct sewage odor.
In the case of the town’s new facility, the smell is still there. Also there, however, are new pieces of equipment that have allowed for an increase in capacity, improvements in the quality of the plant’s effluence, and a decrease in the amount of sludge that has to be trucked to a compost facility.
Orono’s Water Pollution Control Facility, which is now up and running, is a state-of-the-art plant that Superintendent Paul Wintle feels will be a model for other Maine communities.
“We’ll be getting visitors, I’m sure, once the word gets around,” said Wintle, who led the Town Council’s operations committee and Town Manager Catherine Conlow on a tour Monday afternoon.
The facility cost about $15.2 million and took about 2½ years to complete. Olver Associates of Winterport was the environmental engineer for the project.
The old facility had the capacity to process about 3.5 million gallons of wastewater a day, Wintle said. The new plant can take on about 5.65 million gallons. About 52 percent of the water handled there is from the University of Maine campus, while the other 48 percent is town waste.
It’s also better positioned for overflow during heavy rain, he added.
One of the landmark improvements has been the addition of a building in which the wastewater is disinfected with ultraviolet light instead of the standard chlorine bleach or other chemicals.
“It’s a safer way of disinfecting,” said Wintle, who is sure Orono’s facility is one of few in the state with the UV system.
“I think we’re heads and shoulders above other communities of our size in the state of Maine,” Councilor Lianne Harris said.
In its new headworks building, the facility has a new system of biological nutrient removal, or BNR, in which bacteria remove nutrients such as nitrogen and phosphorus that can deplete oxygen if left untreated in a body of water. BNR uses microorganisms to take in the nutrients during different points in the treatment process.
Nutrient removal helps reduce sludge, as does a new belt press, which removes large pieces of trash early in the process.
“The less we have to haul, the better off we are,” Conlow said.
The facility also has a new aerated grit chamber that allows grit from the wastewater to settle to the bottom of the chamber from which it is pumped out, washed, collected and removed. Too much grit can clog up the wastewater system, Wintle said.
Although most of the treatment facility’s new equipment has been online for several months, Wintle and his crew will continue to make adjustments as they receive more data.
“Everything does what it’s supposed to do,” Conlow said. “It’s just a matter of tweaking it to get it to perform a little better.”