Cambria’s services district had planned to shut down the town’s emergency water-supply (EWS) project at the end of April, having completed a three-month test run.
However, rising nitrate levels in treated water from the water-reclamation plant triggered the quick decision to turn off the facility nearly two weeks earlier, so the district wouldn’t continue to violate terms of a temporary water-quality permit to operate the plant.
Faced with nitrate levels twice as high as that permit allows, but half of the 10 milligrams/Liter (mg/L) that the state allows in drinking water, Cambria Community Services District officials ordered the plant turned off April 17, probably until at least mid-July, according to Bob Gresens, district’s in-house engineer.
He said he immediately notified the state water board of that decision and action.
District General Manager Jerry Gruber told CCSD’s Board of Directors on April 23 that tests showed nitrate levels of 5 mg/L in the groundwater, and that the district’s so-called “Title 22” permit limits that level to 2.3 mg/L.
Gresens explained April 28 that the state’s restriction is based on the customary low nitrate levels in the aquifer’s groundwater and a state water board requirement that the plant not degrade the quality of that groundwater.
The state restricts nitrate levels in water, the district engineer said, because while nitrate is considered harmless in small amounts, excess quantities “can affect the blood to where the hemoglobin won’t transfer oxygen as well into the bloodstream,” he said.
That’s a concern especially for newborns and infants who can develop breathing problems and blue-baby syndrome, according to the U.S. Environmental Protection Agency.
The district’s next step is lowering the nitrate levels in effluent that flows from the district’s wastewater treatment plant to percolation ponds on the same San Simeon Creek Road property on which the emergency water supply project is located. That property includes the aquifer from which the EWS draws its supply water.
Gresens said the district already is implementing some temporary modifications “on a short-term basis.”
Consultants at Carollo Engineers are working on recommendations to correct or reduce the problem in the short and long term, Gresens said. Those potential solutions include “denitrifying” the effluent from the wastewater treatment plant, a series of steps designed to fine-tune the plant’s activated sludge process.
“We’ll still have to do permanent modifications” to the plant, Gresens said, but doing them depends on finding ways to pay for them.
Meanwhile, ratepayers won’t find on their next bills an operational surcharge that was to have been levied for the final 11 days of the plant’s test run. CCSD Finance Manager Patrick O’Reilly told district directors April 23 that while the meter readings had been taken for that billing procedure (designed to test the special software), those fees won’t be charged because the plant wasn’t operating during the final 11 days of April, the period during which the fees were going to be calculated and added to the bills.