Wastewater plant disputes new toxin limits 

Officials with south county’s major wastewater treatment plant are protesting new limits on toxic chemicals released into the Bay, but California regulators say the plant’s release levels could pose health risks.

The South Bayside System Authority, which treats wastewater from Redwood City, San Carlos, Belmont and Menlo Park, has filed an appeal of new limits on dioxins, a class of toxins that are the byproducts of industries such as diesel combustion. Those limits, imposed on the authority in January with the renewal of a five-year permit by the California Regional Water Quality Control Board and the Environmental Protection Agency, are designed to keep the carcinogen out of the Bay.

However, SBSA officials, along with wastewater agencies in Marin and Contra Costa County, say the new limits are impossible to meet.

"We don’t want to pollute the Bay, and we’re doing all we can, but the constraints are completely unreasonable," SBSA board chairman Jeff Ira said. He said regulatory agencies should instead go after polluters such as the freight transportation industry.

The new limits ask wastewater plants to reduce dioxin discharges to almost undetectable levels: a monthly average of 1.4x10-8 parts per billion, or a daily maximum of 2.8 x10-8 parts per billion, according to Lila Tang, chief of wastewater permitting for the California Regional Water Quality Control Board. At the SBSA, daily dioxin discharges were measured at 72.9x10-8 parts per billion, a level that science suggests is unsafe, Tang said. To provide perspective, these amounts would roughly equal barely a fraction of a single drop spread across seven Olympic-size swimming pools.

Although SBSA is considering $250 million in upgrades to its 25-year-old facility, there is no technology that would reliably remove dioxins to meet state and federal limits, according to Director Daniel Child. Other wastewater plants, such as ones in South San Francisco and San Mateo, have not been asked to meet the new limits yet, but expect that will happen when their permits are renewed.

Whether the appeals will be effective remains to be seen, since the state sets limits to comply with EPA regulations. It’s possible that state agencies could begin to institute limits on unregulated dioxin producers as Ira suggests, Tang said.

There is no reason to let wastewater agencies off the hook for dioxin cleanup, according to Deb Self, director of Baykeeper, a San Francisco-based environmental watchdog group. "These plants are purveyors of industrial waste, and they are accountable under federal law like any other polluter," Self said. "Under the Clean Water Act, no one is allowed to violate these standards."

bwinegarner@examiner.com

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