By Bonnie Adams, Government Editor
Westborough ?Sewerage is not something that most people think about on a regular basis, unless there is a situation at their home such as a septic system failure. But for municipal officials, who must determine how to operate and pay for their community's wastewater plant, while adhering to strict, unfunded state and federal mandates, it is an issue they think about constantly.
On June 6, members of the Westborough and Shrewsbury Boards of Selectmen and Finance committees were invited to tour the Westborough Wastewater Treatment Plant, which recently had a $54 million upgrade. According to officials, the renovations were necessary to update parts of the plant that had exceeded life spans. But more significantly, the upgrade was necessary in order to comply with more stringent EPA and DEP mandates regarding phosphorous removal.
The plant, which last had a major upgrade in 1999, serves Shrewsbury – 60.8 percent, 4.39 million gallons of daily flow (mgd); Westborough – 35.48 percent, 2.89 mgd; and Hopkinton – 4.7 percent, .4 mgd.
During the tour, Thomas Parece, an associate vice president of AECOM, the firm that oversaw the renovations, and Chris Pratt, a project manager at the plant, explained the basics of how the plant functions.
The plant has 11 employees, most of whom are Massachusetts grade 7 level managers, Parece said. But the plant, he added, is designed so it can “operate by itself.” A state-of-the-art system, SCADA, monitors equipment continuously and makes necessary chemical adjustments.
The plant pumps 1,800 tons of wastewater a year at approximately 6 million gallons a day and 75,000 cubic feet a minute. In the case of a power outage, a diesel system is in place as a backup, Pratt said. Fortunately, he added, the plant rarely ever loses power, which included during the October 2011 storm when much of Westborough lost power for close to a week.
There are three types of treatment done at the plant, Parece said: mechanical, biological and chemical. After going through those processes, the end result is sludge that is trucked to the Upper Blackstone Waste Water Treatment Facility in Millbury and water that is released into the Assabet River. The whole process takes about 24 hours, he added.
New odor-controlling equipment was installed in the Headworks Building, Parece said, an important step considering the plant's proximity to its Route 9 neighbors. A new lime silo ensures process stability for biological phosphorous reduction. Over $3 million in upgrades included energy reduction, conservation measures and incorporating green technologies.
One of the plant's outdoor tanks was destroyed by the heavy snowfalls during the winter of 2010-2011. That tank is currently being rebuilt; other modifications were made throughout the facility to better accommodate future snowfall, Pratt said.
Part of the upgrade included a new treatment building, which will reduce the phosphorous from 2 to less than 0.1 mg/L. Of concern to officials, though, is if that will be enough in the future to satisfy the EPA, DEP and environmental groups.
Phosphorus is found in agricultural fertilizers, manure and organic wastes in sewage and industrial effluent, but the primary source is from laundry and other cleaning detergents, Parece said. Environmental groups and municipal officials agree that excessive amounts can be harmful to fish and plants in bodies of water, but disagree on what is considered an excessive level.
The project was funded using a 20-year loan from the Massachusetts Department of Environmental Protection State Revolving Fund at 2 percent interest and an approximately $7 million grant from the American Recovery and Reinvestment Act of 2009. It was completed $1.8 million under budget, and more than a month ahead of schedule, officials said.