Rendering courtesy of the U.S. IBWC

The South Bay International Wastewater Treatment Plant near the U.S.-Mexico border is undergoing a major rehabilitation and expansion aimed at increasing treatment capacity to 50 million gallons per day.

The U.S. section of the International Boundary and Water Commission issued a revised contract award Oct. 13 to PCL Construction—the contractor in a design-build team with engineer Stantec—increasing the scope of phase 1 of the South Bay International Wastewater Treatment Plant's expansion to eventually treat 50 million gallons per day of raw sewage from the Mexican border.

The revised contract increases PCL's award to $552 million for expansion of the plant's primary treatment facilities, with substantial completion scheduled for 2031.

Sewage has been flowing from Mexico into the Tijuana River and stateside neighborhoods such as Imperial Beach for at least the last two decades. When the Stantec/PCL team initially won the contract to expand the plant in 2025, U.S.…