Long Island Sound Reaps Benefit of Upgrade

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Comprehensive $100 Million Facility Upgrade Achieves TN Goals

Due to water quality concerns in Long Island Sound, treatment facilities throughout Connecticut have to adhere to stringent total nitrogen (TN) standards. This is no small challenge for many of the larger plants like the Mattabassett District’s 35 million gallons per day (MGD) Water Pollution Control Facility.

This regional facility, which serves several central Connecticut communities, was originally constructed in the 1960’s as a secondary plant on a relatively constrained site.

To provide additional capacity needed by member communities, upgrade aging infrastructure, and achieve stringent TN standards, Wright-Pierce worked with the District to design a comprehensive $100 million facility upgrade.

In order to provide enhanced nitrogen removal on a very tight site, Wright-Pierce developed a unique configuration of the well-proven four-stage Bardenpho process.This included conversion of the existing four complete mix aeration tanks to the four-stage process, along with two new aeration tanks and a unique side-stream reactor to handle high nitrogen recycle stream from the merchant sludge processing and incineration operations.

The facility upgrade also included a new sludge incinerator with state-of-the-art air pollution control systems.

Improving water quality in Long Island Sound The upgraded facility was completed in 2015 and is currently achieving a seasonal TN limit of 3.4 mg/L.

For more information about this project and our Wastewater Engineering services please contact:

Chris Pierce, PE
Senior Project Manager
Associate, Vice President

Christine Kurtz, PE
Project Manager