(The following story by Abby Sewell appeared on the Desert Dispatch website on January 7.)
BARSTOW, Calif. — Water sample test results show that the Barstow wastewater treatment plant is functioning normally after an oil sludge spill on BNSF property overflowed into the city sewer system in early December.
The city and BNSF are still trying to determine how the incident happened and how much it cost to fix.
The Lahontan Regional Water Quality Control Board received water sample test results and signed off on the clean-up at the wastewater plant on Dec. 19, said Lahontan senior engineer Cindi Mitton. The city took samples of treated wastewater on Dec. 12 and sent them to an outside lab to be tested for oil and grease. No detectable levels were found, Mitton said Wednesday.
The spill was reported on Dec. 4, after storage tanks used by BNSF to hold partially treated oil sludge overflowed due to an equipment malfunction, San Bernardino County Fire Department hazardous materials specialist Greg Zeigler said at the time. The railyard treats its own petroleum waste, which then goes to the city’s wastewater plant for further treatment. A large amount of oil sludge pooled inside the BNSF treatment facility and an unknown amount flowed into the city’s sewer system.
The overflow to the wastewater treatment plant did not shut down the entire facility, but it damaged the headworks, which filters solids from the sewage, and killed microbes in the tanks used to purify the treated wastewater.
The oil was immediately skimmed off of the water held in the plant’s clarifying tanks, but Lahontan could not sign off on the clean-up until lab results returned, Mitton said. The city kept its treated wastewater contained in one on-site pond and refrained from using it for irrigation or other outside purposes until Lahontan had approved the clean-up, she said.
Mitton said the water board’s main concern in requiring the sampling was that the oil could harm the treatment plant’s operations, not that the oil would get into the groundwater in any significant quantity.
The city took daily samples after the spill, until the lab results came back showing no detectable level of oil and grease, city spokesman John Rader said.
The costs to the city of the additional sampling, labor and chemicals are still being calculated, he said. Both the city and BNSF are conducting internal reviews of the incident, and the rail company will provide the city with a report identifying what measures it will take to prevent future incidents. Rader said the city expects to complete its own audit of the spill by the end of February.
BNSF spokeswoman Lena Kent said the railway has agreed to pick up the entire cost of remediation at the wastewater plant.
Zeigler said Wednesday that the clean-up at the BNSF yard is still in its final stages. He did not have an exact figure on the volume of oil sludge that had spilled.