City of San Diego Secondary Treatment Waiver

The City of San Diego submitted a consistency certification for the reissuance of its secondary treatment waiver for the municipal discharges from its Point Loma Wastewater Treatment Plant (WWTP). The waiver reissuance would be needed to allow San Diego to continue to discharge effluent receiving less than full secondary treatment in terms of total suspended solids (TSS) and biochemical oxygen demand (BOD). If no waiver were granted, the City would be required under the Clean Water Act to implement upgrades meeting secondary treatment requirements, which would mean removal of 85% of both TSS and BOD. With a waiver, CWA Section 301(h) and (j) require, among other things, removal of 80% of TSS and 58% of BOD.

Other coastal municipalities that had sought past waivers have now upgraded to secondary treatment. San Diego is pursuing a different approach: as an alternative to upgrading to secondary treatment, they propose to reduce wastewater flows to the plant, through water recycling, which then reduces flows (and pollutant loads) into the ocean.

On December 9, 2014, the City of San Diego expanded and updated its commitments to water reuse, in a Cooperative Agreement with San Diego Coastkeeper, the San Diego Chapter of Surfrider Foundation, the Coastal Environmental Rights Foundation, and the San Diego Audubon Society. This agreement commits San Diego to a compliance schedule for initially implementing at least 15 million gallons per day (MGD)of potable water reuse by end of 2023, at least 30 MGD by the end of 2027, and ultimately achieving at least 83 MGD of wastewater reuse by the end of 2035. The Regional Water Quality Control Board’s Order incorporates the City’s commitments to continue to pursue and implement its recycled water program, converting wastewater into potable water, under a program called “Pure Water San Diego.” The US EPA, San Diego Chamber of Commerce, Surfrider Foundation, San Diego Coastkeeper and Coast Law Group all testified in favor of the waiver.

A representative from the US EPA testified pointing out that the associated discharge empties into federal waters – thus prompting this agenda item. The EPA has the sole responsibility of acting on the waiver. They pointed out that the City has already met very stringent requirements that do not adversely effect the ocean environment. The performance of the facility has improved over the past 20 year and meets permitting authority requirements by a wide margin.

The opposition, Steve Ray, claimed that the same amount of wastewater would be discharged in 2050 than there is today, even with Pure Water, due to rapid population growth that will result in more wastewater discharges and therefore the waiver should not be granted.

During deliberation, Commissioner Shallenberger highlighted that Pure Water San Diego proves that “there is affordable technology that can truly answer water supply problems. We don’t need anything fancy or detrimental if we don’t want to” – apparently in reference to the benefits associated with wastewater recycling when compared to costly desalination and other similar infrastructure projects.

The waiver concurrence was approved unanimously.

‍

By approving the Secondary Treatment Waiver, San Diego will be able to pursue the Pure Water San Diego wastewater recycling project in the near future .Wastewater recycling is a cost effective solution with multiple benefits to water quality and water supply needs for the region. The waiver requires at least 83MGD of wastewater recycling by 2035.