EPA, in partnership with U.S. Section the USIBWC and Mexico, continues to address urgent transboundary pollution issues

The EPA, in partnership with the U.S. Section of the International Boundary and Water Commission (USIBWC) and Mexico, continues to address the urgent transboundary pollution issues in the San Diego/Tijuana region. Below is an interim update on specific progress made since our May 2023 Eligible Public Entities Coordinating Group (EPECG) and public information meetings:

• Mexico has completed the rehabilitation of the Oriente Collector, completed 20% construction of the new International Collector, and will complete by December 2023 installation of the pressurized lines carrying wastewater and river water to the coast. Mexico will also soon begin repairs of Pump Station 1. Combined, these projects in Tijuana will help prevent future spills of up to 58 million gallons per day (mgd) from entering the U.S. Finally, Mexico plans to issue a solicitation for bids on the design and construction of a new 18 mgd wastewater treatment plant at San Antonio De Los Buenos in late 2023. Mexico expects to complete construction in two years.
  
  
• USIBWC recently announced immediate repairs (Junction Box 1 replacement, primary sedimentation tank cleaning and rehabilitation, and influent pumps rehabilitation) to the South Bay International Wastewater Treatment Plant (SBIWTP). Over the next 9-12 months these repairs will substantially improve compliance with the discharge permit. Incremental water quality improvement is expected to be seen much earlier.
  
  
• With respect to the USMCA project to expand the SBIWTP, as discussed previously, the full project costs (for expansion from 25 mgd to 50 mgd with a peaking factor and anaerobic digesters) have substantially increased from the original estimate of $300 million, largely due to a more thorough cost analysis performed during the pre-construction phase, in addition to unanticipated costs associated with rehabilitating the plant prior to expansion, inflation, market conditions, and labor shortages.

Because the updated cost estimates greatly exceed the available funding, EPA and USIBWC will proceed with a phased approach for the expansion of the SBIWTP to a 50 mgd plant with a peak capacity[1] of 75 mgd (allowing the plant to treat peaks in volume of water entering the plant). Anaerobic digestion is not included. Although the estimated cost for this project exceeds available USMCA funding by $310 million +/- 30%, EPA and USIBWC will proceed with a phased construction approach commensurate with available funding. Senators Alex Padilla and Dianne Feinstein called upon Senate leadership to include $310 million in the upcoming emergency supplemental bill to allow complete up-front funding for the expansion of the plant, which would allow for a much faster project completion. However, these additional funds are not secured at this time.

Nevertheless, USIBWC will issue a pre-solicitation notice in mid-October and solicit bids for this phased project in late fall 2023. Once selected, the design and construction contractors will develop an updated project schedule, which we will share with you. It’s important to note that the proposed SBIWTP expansion, in combination with the wastewater improvements in Mexico, will result in the elimination of approximately 90% of untreated flows entering the Pacific Ocean.