RANCHO MURIETA, CA (MPG) - Rancho Murieta Community Services District crews worked around the clock from Nov. 15 to Nov. 17 to prevent a sewage spill at Lift Station 6B, after a series of equipment failures and heavy rain overwhelmed one of the community’s most sensitive wastewater stations.

Because the lift station sits near the wooden bridge, any spill into the Cosumnes River could trigger costly state penalties, similar to the fines the district incurred in 2006 when treated wastewater accidentally entered the river.

District directors unanimously approved the Lift Station 6B repair and cleanup at their Nov. 19 board meeting. Board President John Merchant estimated the total cost could reach $250,000.

The trouble began Friday night, Nov. 14 when a low-level alarm was reported around 10 p.m. and cleared by staff. But the more serious problems surfaced the next afternoon. At about 3 p.m. Saturday, Nov. 15, another low-level alarm was triggered at the station, prompting an operator to respond.

Interim Operations Director Travis Bohannon said the station’s programmable logic controller (PLC) unexpectedly stopped controlling pump levels, and the backup float system – designed to take over when levels rise or fall beyond setpoints – also failed to engage. As a result, the pump continued running until the wet well dropped to roughly half a foot, triggering the alarm. The lower float was later found to have failed and has since been replaced.

When the operator arrived, he manually refilled the wet well to 4 feet and returned the pumps to automatic mode. But the system could only draw the level down to about 2.5 feet and no lower, indicating the pumps were no longer operating at full efficiency. Bohannon responded to the site and suspected that air and grease  had entered the 4-inch main when the wet well was pumped nearly to the bottom. The pumps were not damaged, he said, but they were unable to keep up with incoming flow.

“Once the rain started, I knew we were going to need Vactor trucks due to the amount of rain that was forecasted in a relatively short period of time,” Bohannon said. The Vactor truck began hauling effluent from the lift station to the wastewater plant.

Once the rain became a deluge, Bohannon summoned two more Vactor trucks. During the height of the storm, all three trucks rotated continuously.

“We had to have continuous pumping,” Bohannon said in his email response. “Once the rain kept coming down, one truck couldn’t keep up.”

After the heaviest downpour ended, Bohannon released one truck, but two remained on site for two full days, operating 24 hours a day until early Monday morning. In total, five CSD employees worked rotating shifts throughout the weekend to keep wastewater moving and prevent an overflow, Bohannon said.

Compounding the problem was significant inflow and infiltration (I&I) discovered during the storm. After Bohannon alerted him to earlier issues, Utility Supervisor Corey Carskaddon inspected manholes during the peak rainfall and found an illegal tap on De La Pena and multiple uncapped cleanouts at The Retreats, all allowing stormwater to pour into the sewer system. Staff cut off the tap and capped the cleanouts, though additional storms will be needed to gauge how much these fixes reduce inflow.

District staff are continuing to investigate the cause of the weekend emergency. When asked at the board meeting whether outdated equipment had played a role, Bohannon said the float switches were not old and had been installed only a couple of years ago. 

One long-term effort already underway is to locate and prepare to use a separate 10-inch force main that was believed to exist but had never been mapped. The staff located the downstream end of the line near the yellow bridge, confirming its position. Work is now underway to connect the larger pipe to the lift station in addition to the small pipe. The intent is “make sure this never happens again,” Bohannon told the board.

The emergency formally ended Monday morning when wet-well levels stabilized, and the pumps met normal demand without assistance. The final Vactor truck was released shortly afterward.

Merchant told the board he authorized the initial work and said it may evolve into a $250,000 project.

Merchant was also the board president in 2006 when about 20 million gallons of chlorinated water spilled from Bass Lake into the Cosumnes River, and he ended up appearing before the state Regional Water Quality Control Board. 

Merchant recalled the incident at the Jan. 20, 2023, board meeting. The board was deciding whether to loan $115,816 to the Rancho Murieta Country Club for emergency repairs and upgrades to the Bass Lake pump that was damaged in the New Year’s storm. The pump irrigates the north course using reclaimed water from the district. 

According to the discussion, a failing pump house would have been bad for the country club because it couldn’t irrigate, and for the district because it couldn’t remove reclaimed water.

The worst-case scenario happened to the district in 2006 when the state fined CSD after reclaimed water spilled into the Cosumnes River from Bass Lake.

Merchant said the district was fortunate to receive a $200,000 fine, noting it could easily have reached a million dollars. In addition to the fine, the district incurred substantial permit-related work and significant legal expenses.

“This little miscalculation we had – in the amount of rain we were going to get and the amount of water we could hold in our recycled-water pools – cost us in excess of half a million dollars,” he said. “So what we’re doing here, whether it’s secured or unsecured, we’re betting $100,000 that we are not going to be fined another half a million.”

The board approved the 2023 loan from sewer reserves, which the country club is still paying off.