BANGOR, Maine — Due to an Environmental Protection Agency rule, the Bangor Water District will add ultraviolet reactors, worth $3.8 million, to the city’s water supply system to kill an organism that is not currently present in it.
The Water District will purchase two Calgon 24-by-36-inch Sentinel medium pressure UV reactor units at a total present worth of $3.8 million to kill cryptosporidium organisms that apparently don’t exist in the Floods Pond watershed. The projected cost includes the price of equipment, a building, and upkeep of the units during their 20-year lifespans.
“The regulation came out in 2006,” said Kathy Moriarty, Bangor Water District’s general manager. “We’ve been testing for two years and we don’t have it, so we requested a variance with the EPA.”
After consulting with the EPA, it became apparent to Moriarty and fellow district officials that it would be cheaper in the long run to install the reactors to kill the nonpresent organisms than the cost of continuous testing and documenting of results.
“It would have required a lot of sampling, an inventory of the wildlife in our watershed area, and then we had to do modeling to show how fecal material enters source water, and then do more sampling in hot spot areas where wildlife would be present,” Moriarty explained. “And all that was just to see if numbers were low enough to get a variance.
“And if you found just one, you’d still have to have a reactor.”
Moriarty said to her knowledge, there is only one town or city in the country that is still pursuing a variance from the EPA.
“That’s Portland, Oregon. They’ve already spent millions on studies and they’re still preparing plans for a reactor if they need one after all is said and done,” she said.
The Water District will construct a building, roughly 42 feet by 56 feet, to house the reactors and the piping leading in and out of the structure alongside the Butler Ozone Water Treatment Facility at Floods Pond.
The district’s board of trustees was presented with 10 options from three different companies.
“We met with our engineers over three days, looking at the bids along with state drinking water program representatives,” Moriarty said. “On our third day the staff made a unanimous recommendation and we had unanimous approval.”
District engineers recommended the Calgon Sentinels over low-pressure reactors that were bigger in size — 4 by 10 feet — and more expensive at $5.1 million.
“They both have the ability to treat 13 million gallons per day,” said Moriarty. “Low pressure often is looked to be a better unit because there is less energy required, but the present worth cost still outweighs the energy savings overall.”
The reactor building and system should be complete and active by Oct. 1, 2013. Construction will begin July 1, 2012.
“We’re still in the design phase, but we’ll be sending out requests for bids to construction companies in the near future,” Moriarty explained.
Cryptosporidium is a parasitic coccidian protozoan found in the intestinal tract of many vertebrates, where it can sometimes cause disease. Ultraviolet light inactivates them so they cannot replicate.