As noted above, discharges from the San Antonio de los Buenos Treatment Plant are the primary source of ocean pollution in Imperial Beach and Coronado during the summer months. The plant accepts untreated sewage from neighborhoods in western Tijuana as well as up to 28 million gallons per day of water from the Tijuana River.
EPA’s plan would reroute the Tijuana River water that currently goes to the San Antonio de las Buenos Plant to the expanded International Treatment Plant and to the new primary treatment plant that will be built on the U.S. side of the border. Instead of being discharged untreated into coastal waters, this water will be treated and either used as recycled water in Mexico or discharged 3 miles offshore from the South Bay Ocean Outfall.
The sewage from neighborhoods in western Tijuana that currently goes to the San Antonio de las Buenos Treatment Plant will continue to go to the plant, however, the plant will be reconstructed so that it can reliably treat up to 5 million gallons per day of raw sewage.
In combination, these projects will mean that raw sewage is no longer discharged directly into coastal waters from the San Antonio de las Buenos Plant. EPA estimates that these projects will reduce beach closures in Imperial Beach and Coronado by up to 95%.