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Release Date: 3/19/1999
Contact Information: Leo Kay, U.S. EPA, (415)744-2201, Dion McMicheaux, IBWC, (619)662-7600

    SAN FRANCISCO -- The U.S. Environmental Protection Agency and the U.S. International Boundary and Water Commission released a final study today that identifies the next step in upgrading the South Bay International Wastewater Treatment Plant in south San Diego to better protect San Diego's coastal resources.

    The study, called the "Long Term Treatment Options Supplemental Environmental Impact Statement," recommends the construction of a series of secondary treatment ponds that will treat 25 million gallons per day of sewage from Tijuana, Mexico.  The ponds, which would be located on a 36-acre site adjacent to the current international plant site, would be concrete lined and would be designed to produce treated wastewater that would meet both Clean Water Act and California Ocean Plan standards.

    "The secondary treatment ponds represent the best technology to treat sewage from Tijuana, providing an added layer of protection for San Diego's people and precious ocean environment," said Felicia Marcus, EPA regional administrator.  "In the absence of a fully effective program in Tijuana to control industrial discharges, the ponds can adjust to the varying wastewater quality and flow that the current primary system produces.   Providing additional treatment to the wastewater from Mexico is imperative."

    USIBWC Commissioner John Bernal said, "The USIBWC is anxious to conclude this project, which will not only resolve the long-standing regional environmental problem, but will do so in a manner that is responsive to the desires of the international San Diego/Tijuana community."

    The ponds are also the most cost effective alternative compared to the other secondary treatment technologies that the EPA and USIBWC evaluated.  The ponds will cost approximately $48 million less in terms of capital costs, and $2 million less annually for operation and maintenance than the average cost of the activated sludge alternatives that the agencies also evaluated.  In concert with constructing the ponds, EPA has pledged an additional $9 million to support other needed infrastructure projects in Tijuana.  

    The initial study, originally released in February 1998 in draft, analyzed three major alternatives for providing the required secondary treatment for the international plant.  After considering comments received from the public, the EPA and USIBWC are proposing secondary treatment ponds for the plant.

    During the development of this study, some local residents expressed concerns about potential odors and pests from the secondary treatment ponds.  EPA and USIBWC have identified design features, such as surface aeration, for the secondary treatment pond system that will prevent the presence of mosquitoes or flies.  The agencies also conducted extensive studies that demonstrated no significant odor impacts with the pond system, whereas other alternatives would be more likely to produce odors.

    There were concerns from the public and elected officials about the ability of the ponds to be expanded.  Construction of the ponds in the United States will not prohibit expansion at the international plant site or at other sites in Tijuana.  The plant could be expanded using other treatment technologies, if necessary.  Any limitation on expansion potential is outweighed by the superior reliability and cost effectiveness of the pond alternative.  "Our chief objective is the delivery of a speedy, reliable and cost-effective solution for the South Bay," said Marcus.  "We are eager to take this next step and get on with the job."

    Elected officials and some members of the public have requested that EPA and USIBWC consider an alternative called "Bajagua," which would move the ponds to a site in Mexico.  The status of the Bajagua project is described in the Final SEIS.  Elected officials and some members of the public have also recently suggested that we solicit other potential alternatives not previously identified.  We invite public comment on these ideas.  

    The agencies will be seeking public comments on the Final SEIS until April 19, 1999.  A public workshop on the final study will be held at Southwest High School on April 12 from 5 to 6:45 p.m., followed by a public hearing from 7 to 9 p.m.  After review of public comments, the EPA and the USIBWC will issue a final decision regarding secondary treatment.

    The South Bay International Wastewater Treatment Plant was constructed to address the ongoing problem of dry-weather sewage flows that exceed the capacity of the City of Tijuana's sewage system. These flows have resulted in the contamination of the Tijuana River and the near shore coastal waters of San Diego.

    In 1997, the international plant began treating 13 million gallons per day as an advanced primary facility. Treated wastewater was discharged to the City of San Diego's Point Loma Wastewater Treatment Plant until the South Bay Ocean Outfall was completed in January 1999.  Currently, the plant is treating at its capacity of 25 million gallons per day, with treated wastewater being discharged 3.5 miles off-shore.  

    Testing of the advanced primary effluent from the plant has found a continuous problem with acute toxicity, as well as episodic exceedences of dioxin limits.  Although ongoing ocean monitoring will help to identify any changes to the environment from the discharge of the treated effluent, these exceedences can be fully addressed by providing secondary treatment to the wastewater.  As part of the USIBWC's NPDES permit from the Regional Water Quality Control Board, USIBWC is required to provide secondary treatment by December 31, 2000.

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