Sewage Spill Closes Large Area of Mission Bay

An estimated 2,000 gallons of sewage sludge has spilled from a holding pond on Fiesta Island, coating more than a mile of shoreline with a black, smelly residue and prompting county health authorities to close a large section of Mission Bay.

County Public Health Engineer John Melbourn said the quarantine, which covers the eastern waters of the bay between the island and the mainland as far north as the visitors’ center, would be in effect for at least a week.

The spill occurred early Wednesday when an earthen berm separating one of the ponds used to dry treated sewage sludge apparently gave way. About 1.3 million gallons of sludge spilled from the pond into a secondary containment area, but city officials estimated that only 2,000 gallons seeped from there through a storm drain into an area of the bay known as Enchanted Cove.

“Luckily, our containment system worked, and we were able to keep most of the sludge from entering the bay,” said Yvonne Rehg, a spokeswoman for the city’s Water Utilities Department. “By noon (Wednesday) our crews had most of the sludge vacuumed out of the bay and the leak in the berm patched up.”

Nonetheless, state water quality officials characterized the spill as serious and declared it a violation of San Diego’s sewage discharge permit. They said that penalties of up to $10 per gallon may be imposed upon the city in connection with the episode.

“When you can see evidence of a spill for a mile along the shore, then you know you’ve got a significant amount of sludge out there,” said Mike McCann, a senior engineer with the Regional Water Quality Control Board. “It’s something we’re very concerned about.”

The regional board’s staff is conducting an investigation into the spill and likely will recommend action against the city to board members at a future meeting, McCann said.

According to water quality officials, this week’s spill differs from the typical contamination of the bay because it involved sludge, a highly concentrated byproduct of sewage that is processed at the city’s Point Loma treatment plant. The sludge is pumped into 31 ponds on Fiesta Island and allowed to dry for 30 to 60 days before being disposed or used as fertilizer.

Normally, quarantines of the bay follow breaks in sewer lines that allow untreated household wastes to seep into its waters.

“With raw sewage, you don’t get as many solids and the material tends to dissipate a lot quicker,” McCann said. “But sludge is much more concentrated, and will settle out on the bottom and the shoreline. Our concern is that the material could be re-suspended (in the water) and present a threat in the future.”

Melbourn said that exposure to sludge could create numerous health problems, ranging from gastrointestinal disorders to infectious hepatitis.

“The sludge has gone through a heat-treatment process (at the plant) but it still contains pathogens that pose a risk,” Melbourn said. “The critical thing is whether you ingest the material. That can cause serious difficulties.”

He said that results of tests of the bay would be available today but noted that the quarantine will remain in effect until a series of additional samples over the next week indicate the water is clean. The area now closed to water sports could be reduced or expanded during that time, depending on what the tests show.

Water utilities officials said the six-foot crack in the sludge bed’s earthen berm appeared about 6 a.m. Wednesday and apparently was caused by the earthquake that rattled San Diego County a day earlier.

“Our crews are out there 24 hours a day, and they felt that earthquake,” Rehg said. “They seem to think that was responsible, but it’s still under investigation.”

Rehg said the sewage flooded through the opening and then pooled in a second containment area surrounding the pond. Apparently, some sludge then leaked through a crack in the containment area’s wall and into a storm drain, which carried it into the bay.

By 8 a.m. Wednesday, the city had deployed trucks with large vacuum hoses and began sucking the solid materials out of the bay. Additional cleanup along the shoreline continued Thursday.

Rehg said Wednesday’s spill was only the second such seepage of sludge into the bay in six years. The last leak, which also prompted a quarantine of the bay, was caused by ground squirrels that burrowed in the berm and caused it to give way.

“Obviously, Fiesta Island wasn’t meant to be a permanent solution for our sludge problem,” Rehg said. Negotiations are currently under way with the Navy to use property at Miramar Naval Air Station as a sludge drying site.

The spill marks the latest in a series of setbacks for San Diego’s beleaguered Water Utilities Department. In July, the city was fined $11,931 and threatened with an additional $646,800 in penalties if it fails to meet a series of deadlines for upgrading the notorious sewage Pump Station 64.

The Sorrento Valley pump station has spilled 58 times in seven years, sending 4 million gallons of untreated sewage into Los Penasquitos Lagoon.

Also this year, the city was censured for dumping sludge at Brown Field over a four-year period.