The MWRA was building a 4-mile-long combined sewer tunnel to reduce sewer discharges into Massachusetts Bay, and they needed to ventilate the tunnel and provide odor control. P. Gioioso was hired to construct an underground ventilation building above a stormwater storage tunnel. There were major restrictions for the logistics because of the very small size of the site.

 

The construction includes a cast-in-place concrete structure built below grade. It’s supported by 32 steel piles averaging 120 feet long. The ventilation system includes FRP ductwork up to 54” in diameter and two 75 horsepower vent fans with an airflow of 19,500 CFMs each, with two activated carbon vessels.

 

The project minimizes the visual impact to the public and abutters and is visible just with hatches and vent shaft openings in a parking lot. The project is part of a larger MWRA project that won an Operations and Environmental Performance Award.