Investigation launched into cause of massive sewage spill into Monterey Bay

Marina >> An investigation will be conducted into the failure of a computer warning system at the Monterey One Water regional treatment plant which allowed millions of gallons of untreated sewage to flow into the Monterey Bay for more than eight hours late Friday night and early Saturday morning.

According to Monterey One Water General Manager Paul Sciuto, the investigation began Monday morning and will be conducted by the consulting firm Pinnacle ART. Sciuto says the firm has expertise in root cause and analysis inquiries and is already under contract with the agency. Sciuto said the goal is to take a hard look at the incident and added he expects at least a preliminary report by the end of the week. A final report will be forwarded to the Central Coast Regional Water Quality Control Board, which provides oversight. Monterey One Water was formerly known as the Monterey Regional Water Pollution Control Agency.

“Our job is to treat and convey wastewater and I think we do a pretty good job of it,” Sciuto said. “So to have something like this happen is untenable and it just makes you sick.”

A call equipment failure on the headworks bar screen allowed the untreated wastewater to start backing up, eventually spilling into the ocean outfall without triggering an alarm. The spill began about 8 p.m. Friday and continued until about 4:30 a.m. Saturday, dumping up to 4.9 million gallons of sewage from area toilets, showers and washing machines into the bay from the end of the agency’s outfall pipe 2 1/2 miles offshore and 130 feet deep.

The spill was only spotted when a graveyard shift worker was making the early morning rounds, and agency staff shut off the flow and notified the authorities, including Marina Fire and the Monterey County Environmental Health Department.

Agency officials estimated the total amount of sewage released at about 4.4 million gallons but acknowledged it could be more. The amount of sewage spilled into the ocean was equal to a football field up to about 15 feet deep.

Monterey One Water Government Affairs Director Mike McCullough said this is the first such spill at the agency’s treatment plant.

“It’s usually fail-safe,” McCullough said. “This is a worst-case scenario.”

County environmental health director John Ramirez said he had never heard of such a large amount of sewage spilling into the ocean in such a short period of time, and called the incident a “huge spill.”

After being closed by county environmental health on Saturday due to the spill before testing started, all beaches from Moss Landing to Stillwater Cove were re-opened after testing of samples taken on Sunday showed the area is safe for recreational contact according to state guidelines. However, Monday’s rain triggered an advisory recommending no contact with ocean water for the next three days.

The agency took its own ocean water and beach samples on Saturday and Sunday, and only one from a beach near Monterey Wharf No. 2 on Saturday showed a contaminant level above state limits.

Contact with contaminated water may cause gastroenteritis and other waterborne illnesses, and higher levels of bacteria have been associated with the increased risk of illness, according to public health officials.

Monterey One Water Government Affairs Director Mike McCullough said there is no chance such an incident could occur involving the Pure Water Monterey recycled water project, which will pump highly treated water into the Seaside basin, because there will be no direct pipeline to the basin that does not go through the advanced water treatment plant.

Jim Johnson can be reached at 831-726-4348.