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Vernon WPCF Upgrades Receive 2024 ACEC-CT Grand Award

Several of the major upgrades that were completed as part of the Vernon WPCF improvements.

The American Council of Engineering Companies of Connecticut (ACEC-CT) named Tighe & Bond the Grand Award Winner during their 2024 Engineering Excellence Awards ceremony on January 22. Our firm received the award for the design, permitting, and construction of upgrades to the Vernon Water Pollution Control Facility (WPCF) in Vernon, CT.

The facility treats wastewater from the Towns of Vernon, Ellington, Manchester, South Windsor, and Tolland. Following treatment, the water is discharged into the Hockanum River which then feeds into the Connecticut River and the Long Island Sound. In addition to the U.S. Environmental Protection Agency’s national treatment standards for WPCFs, the Connecticut Department of Energy and Environmental Protection (CT DEEP) imposed stringent limitations on nutrients, namely nitrogen and phosphorus. Nitrogen discharges from WPCFs have been shown to adversely affect marine environments, while phosphorus discharges negatively impact rivers, streams, and impoundments. For Vernon, these treatment goals meant having to reduce the amount of phosphorus and nitrogen discharged from the facility by approximately 90% and 50%; respectively.

The Town enlisted our services to prepare a Wastewater Facilities Plan to identify how best to comply with these new requirements in a cost-effective, environmentally sound manner. The challenges were many because land was not available at the site to accommodate the new structures that are typically required to meet these treatment objectives. Employing innovative solutions, our engineers devised an approach that eliminated the need to construct new structures and buildings.

An upgraded aeration system allows for biological removal of nitrogen and other harmful pollutants.

The approach focused on repurposing the WPCF’s existing structures and incorporating a relatively new yet proven treatment process called IFAS (Integrated Fixed Film Activated Sludge) within existing tanks to biologically reduce the nitrogen, phosphorous, and conventional wastewater pollutants. IFAS blends the process flexibility and advanced treatment benefits of activated sludge with the inherent stability and ease of operation of attached growth film systems.

To meet the ultra-low phosphorous levels required, our design repurposed the WPCF’s Sand Filter Building to house a new cloth media filtration system. Overcoming a number of challenges, the engineers were able to design the entire system to fit within the limited floorspace of the building.

Additionally, our engineers designed a solids processing system to maximize the reuse of abandoned tanks, replaced the chlorine disinfection process with a safer and environmentally friendly ultraviolet light disinfection system, and included energy efficiency measures that resulted in an over $300,000 in grant monies to the Town from Eversource.

A new UV disinfection system replaced chlorine disinfection, making the treatment process safer and more cost-effective.

Tighe & Bond assisted the Town through a series of public meetings and presentations to garner community support for a required funding authorization referendum. The design was completed five months ahead of the contractual schedule, enabling the Town to qualify for a $20M Connecticut Clean Water Fund (CWF) grant, in addition to $14.3M in funding from other towns using the regional facility. Due to an emphasis on value engineering, the project was awarded at $17.8M less than the Town’s initial budget of $85.9M.

Tighe & Bond staff receive the 2024 ACEC-CT Grand Award for Engineering Excellence.