Future Treatment Options at Point Loma (FAQ 3)
Why was the modified permit granted to the City?
The City demonstrated that the amount of Total Suspended Solids (TSS) and Biological Oxygen Demand (BOD) in the discharged treated wastewater was not harming the ocean environment. This is due, in part, to the City's aggressive Industrial Pre-treatment Program, advanced primary treatment at Pt. Loma, and the length and depth of the Point Loma Ocean Outfall, and a comprehensive ocean monitoring program. At one point in the 1990s, when a plan to upgrade the Point Loma plant to a Secondary Treatment level was developed, Federal court intervention stopped the planned upgrade because it was not in the public interest since no harm to the environment could be found.
Does the treated wastewater discharged from the Point Loma Wastewater Treatment Plant cause beach closures?
No. The wastewater outfall, four and a half miles off shore and 320 feet below the ocean surface, does not cause beach pollution. Beach closures are caused by urban runoff, sewage spills, Tijuana River discharge and pollution from animals and birds.
What is the measured impact of the discharge to the ocean?
The City's Ocean Monitoring Program has shown and continues to show that the discharge of effluent from the Point Loma Wastewater Treatment Plant has no negative impact on the ocean waters, its environs, the Point Loma kelp beds, or commercial and game fish taken in the area. There is no indication of any elevated levels of TSS or BOD (the regulated components) in the surface waters at any point; elevated levels in sea floor sediments have only been detected within a very short distance from the ocean outfall.
Is the City trying to avoid proper treatment of wastewater if it defers Secondary Treatment?
Application for the modified permit is a provision of the Clean Water Act. The Mayor, City Council and the Metropolitan Wastewater Department are committed to protecting our ocean environment.
Previous waiver approvals have been granted based on evidence of no environmental impact. Data during this last waiver period still indicates no detectible impact. This information contributes to the discussion as to whether it is necessary for the City to upgrade the Point Loma Wastewater Treatment Plant to a Secondary Treatment Level.
How is Point Loma's outfall different from other treatment plant outfalls?
Point Loma's Outfall is unique; it is the deepest and one of the longest outfalls in the United States. Also, the ocean environment makes the Point Loma outfall very effective; a thermocline (temperature gradient) means that the released sediment stays deep and cross currents and bottom slope features mean that there is no build up of sediment.
What options are available to the City as far as Secondary Treatment are concerned?
There are two options available to the City:
- The City could commit to construct Secondary Treatment at Point Loma. This would require the City of San Diego to implement future rate increases to fund the improvements. The financial costs to upgrade to a Secondary Treatment level would be paid primarily by the ratepayers in San Diego and the residents of the 15 other participating agencies that make up the Metropolitan Wastewater System.
- The City could continue the existing process of renewing its modified permit every five years.