The Biden administration’s $55.9-billion supplemental funding request to Congress for disaster response and other issues includes $310 million for a project to repair and expand the ailing South Bay International Wastewater Treatment Plant in San Diego, Calif. The plant is part of a repeatedly overwhelmed wastewater treatment system on the U.S.-Mexico border that has allowed untreated sewage flows to foul area beaches.

The U.S. Environmental Protection Agency already has $300 million for the project from the U.S.-Mexico-Canada Agreement. The new funding request comes after the U.S. Section of the International Boundary and Water Commission (USIBWC) said their cost estimate for the work had risen from about $627 million to $910 million or more. 

The money would go toward design and construction “to prevent and reduce sewage flows and contamination” in southern California, according to the funding request. On Oct. 27, USIBWC, which operates the South Bay plant, issued a preliminary solicitation notice for a rehabilitation and expansion project.

"If appropriated, the funds will significantly reduce the construction timeline, and reduce costs through economies of scale and the elimination of repeated construction ramp-ups that would be required in a phased project," said Frank Fisher, a spokesperson for USIBWC, in a statement.

In August, Rep. Scott Peters (D-Calif.) and the late Sen. Dianne Feinstein (D-Calif.) asked Senate Majority Leader Chuck Schumer (D-N.Y.) to include $310 million in an emergency supplemental bill.

The Biden administration’s request still requires action from both houses of Congress to approve the supplemental request. “Make no mistake, this is not a ‘mission accomplished’ moment,” Peters said in a statement.

USIBWC expects to issue the request for qualifications for the progressive design-build project around Nov. 27. Construction is expected to start within a year of the contract being awarded. Work is estimated to take at least three years. 

The plant treats average flows of 25 million gallons per day (MGD) of raw sewage coming from both Tijuana, Mexico, and the San Diego area, but has struggled with excess flows coming from south of the border since the Punta Bandera plant near Tijuana was shut down due to pipe failures.

When Tropical Storm Hilary hit the area in August, inflows exceeded the plant’s capacity by 100% for six hours and by 320% for another six hours, necessitating even more repairs, according to USIBWC.

Lack of maintenance over the last 15 years also contributes to the need for repairs, say officials. The project would increase the plant’s treatment capacity to an average flow initially of 45 MGD and then, depending on funding availability, to 50 MGD, with a peak hour capacity of 75 MGD. Even if the work is phased due to funding, it would all be done under the same contract, according to USIBWC.