LAGUNA NIGUEL — A one-mile stretch of Aliso Beach was ordered closed Monday after 16,000 gallons of partially treated sewage spilled into nearby Aliso Creek, an Orange County Environmental Management Agency official said.
"It's undigested sludge and we're just as concerned as if it were untreated sewage," said Larry W. Honeybourne, a spokesman for the agency.
An underground 4-inch, pressurized pipeline operated by the South Coast Water District broke near Alicia Parkway and Aliso Creek Road, spilling the material for 9 1/2 hours, the district said. The break in the main was reported by a cyclist riding along the roadway.
"Once it was discovered, we closed the pipe to eliminate any more sludge from going through the pipe and spilling," said Michael Dunbar, South Coast Water District's general manager.
Dunbar said sludge is sewage that has gone through the district's waste water treatment process and has high concentrations of solid materials. It has the consistency of a "very thin, fine mud," he said.
Although partially treated, Honeybourne said the county ordered the beach closed because of concern for disease-carrying microbes that could come in contact with people swimming at the public beach.
"It's almost summertime, and most of the schools I know are out," Honeybourne said. "And, although it's treated waste, the pathogenic microbes are still there."
The county took samples of ocean and creek water Monday, but results will not be known for at least three days. Until then, the beach will remain closed. Signs warning of the potential health threat were posted Monday, Honeybourne said.
"We will continue to sample on a daily basis," Honeybourne said.
The closure extends a half-mile in either direction from Aliso Creek's mouth, about 100 yards north of Aliso Beach Pier.
"Roughly, the area is from Camel Point on the south to the boundary of Treasure Island Mobile Home Park on the north," Honeybourne said.
Dunbar said the hole in the broken pipe was about the size of a thumb. Water district crews Monday patched the pipe, located three feet underground.
A crew cleaned up the paved roadway. Dirt near the pipeline break will be excavated by a backhoe once it is dry, and it will be taken by truck to BKK Landfill.
The pipe is used to transfer treated waste to a regional treatment facility about six miles from the water district, Dunbar said. At the second facility, sludge is treated again and then trucked to a compost facility. Some of the treated material is also trucked to a general landfill, he said.