November 18, 2013 03:38PM
SOUTHINGTON — Town officials are pondering options for repairing equipment at the wastewater treatment plant that could cost between $165,000 to $6.4 million.
Water Pollution Superintendent John DeGioia said the town’s wastewater treatment plant cannot decompose sludge after it is removed from water passing through it due to a breakdown of equipment designed to perform that function. Instead, sludge has been pumped into trucks and taken to the Hartford-based Metropolitan District Commission plant for the past 18 months, since the machinery failed, he said.
The devices, called digesters, extract sludge from water and break it down, DeGioia said. A digester functions as “a very large stomach” within the wastewater treatment system, he said.
DeGioia said the plant has four digesters, all of which are currently unused and sitting in storage.
Each of the four stages of the digestion process removes additional sludge from water passing through the system, making the water progressively cleaner, he said.
DeGioia explained the basic options concerning the broken digesters. They will either be “rehabilitated or eliminated,” he said.
Town Engineer Keith Hayden said officials would consider factors such as equipment condition and repair cost as they determine the best course of action.
DeGioa said the equipment is aging. Two of the digesters were installed in 1959, he said, while a third was put in place in 1970 and the fourth in 1980.
At an October sewer committee meeting, Assistant Town Engineer James Grappone said engineering firm Tighe & Bond, which was hired to perform an analysis of the digesters, has presented three repair plans to officials.
The $165,000 option would provide for only those repairs necessary to make the digesters operational again. The limited fixes would prolong the equipment’s life by two to five years.
Grappone termed the second plan a “refurbishment” of the digesters, saying the moderate repairs would cost $860,000 to extend the digesters’ exteriors by 10 years and their internal components by 20.
The $6.4 million plan would involve replacement of the digesters’ major mechanical systems. The comprehensive overhaul would extend the entire units for more than 20 years.
If the town opts not to fix the digesters, sludge will continue to be sent to Hartford, De Gioia said, the only difference being that it would be concentrated into liquid form before transport, rather than being shipped in its solid state, as it is currently.