SB Treatment Plant Embraces Efficiency

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Wednesday February 08, 2012

Most people in South Burlington probably give little thought to where their drinking water comes from or where the waste goes when they bathe or flush the toilet. A bill comes in the mail every quarter from the South Burlington Water Department yet, like most of us, they usually don’t think twice about water and sewage.

But behind the scenes are a group of professionals committed to providing their customers with first-class service and adhering to the highest standards in potable water supply while ensuring only high quality treated water goes back into Lake Champlain.

The City of South Burlington recently wrapped up construction on the upgrade and expansion at the Airport Parkway Wastewater Treatment Plant, the City’s largest capital expenditure in recent memory. Regardless, the ratepayers will not see their utility bills increase as a direct result of the project.

Justin Rabidoux, Public Works Director, was intimately involved with the project. He highlights the project as an increase in the plant’s treatment capacity from 2.3 to 3.3 million gallons per day with the addition of an ultraviolet disinfection facility replacing the old chlorine disinfection system. Work also included energy-efficiency upgrades and a solids handling facility producing Class A sludge. Previously the plant produced Class B sludge.

Class A Sludge: An advantage for local farmers 

In the wastewater treatment world, the type of sludge (often referred to as biosolids) says a lot about a city’s commitment to its resources. Class B sludge has very limited practical uses, is more highly regulated, and is often trucked offsite to landfills—an expensive proposition. Class A biosolids are used as an organic farm fertilizer. It is economically beneficial and a greener alternative that provides benefits for our environment.

“Prior to this upgrade, we had to pay a subcontractor to dewater our sludge before we paid to have it hauled to landfills where it served no useful purpose,” said Rabidoux. “Now, we are producing clean and green organic fertilizer that is prized by farmers. It just makes sense.”

Recycling byproduct in the form of energy

High efficiency turbo blowers and a microturbine generator were two primary energy efficient components included in the Plant’s upgrades. The turbo blowers produce the air necessary for the treatment process while the microturbine generator, which is powered by methane gas naturally produced by the treatment process, utilizes the exhaust gas to operate boilers for heating the digested sludge as well as the Plant’s buildings. The amount of natural gas required to supplement the methane as a fuel has been greatly diminished, further offsetting the cost of the project over the lifecycle.

“The plant is operating better than our expectations,” said Rabidoux. “Even though we increased capacity by nearly 50 percent, the operating costs are projected to decrease by 10–15 percent. The professionals at Hoyle Tanner and PC Construction did an incredible job in the design and construction of this plant, working very closely with us to get the project completed within budget and schedule.  We are extremely proud of this project and it should serve as a model for others in the area.”

The project was designed by the Burlington office of Hoyle, Tanner & Associates, an engineering firm with headquarters in Manchester, New Hampshire. Construction services were provided by South Burlington-based PC Construction, one of the nation’s largest employee-owned contracting firms.

SOURCE: PC Construction Company