South County sewage plant repairs have cost millions — with more on the way

With $1.5 million in improvements already underway and a separate $20 million project in the pipeline, the South San Luis Obispo County Sanitation District is spending big as it attempts to update the aging 50-year-old wastewater treatment plant in Oceano.

Most residents won’t notice the changes in their daily lives — toilets will still flush and sinks will keep draining like they always have. But the upgrades are necessary to keep the plant running smoothly and prevent potentially disastrous malfunctions like the sewage spill that occurred at the Oceano plant in 2010, according to District Administrator Gerhardt Hubner.

Walking through the plant, there are several areas in obvious need of improvement.

Cracks zigzag across many of the large, squat cylinders that are key to various aspects of the water treatment process. One of the cylinders leaks into a dumpster below. Then there are hidden problems that workers can’t see because, without a backup, they haven’t been able to shut down parts of the plant for maintenance.

To address these problems, the district board has embarked on an ambitious $1.5 million plan — $500,000 for a new grit-removal structure to remove fine particles from the sewage; $600,000 in improvements to the plant’s headworks, which removes non-organic material like trash from the water; $380,000 to clean one of the plant’s two digesters, where bacteria break down organic material in the sewage; and $36,000 to rent equipment to help with the cleaning.

The grit-removal structure was added late last year, while the headworks improvements project is ongoing. The digester clean-out was an unanticipated but necessary cost for the district, Hubner said. It was approved by the board April 5.

Ratepayers in the district — which covers Arroyo Grande, Grover Beach and Oceano — likely won’t see higher bills for this work beyond the rate increase that took effect about a year ago and tops out in 2019, Hubner said.

The rate change increases the average residential customer’s bill incrementally by about 70 percent through 2019. (The district charges a flat rate based on the type of building or business being billed). The first jump was from $14.86 to $19.60 in July 2016. It is expected to increase to $21.56 this coming July.

The rate increase was approved to help pay for much larger changes at the plant:

▪  A redundancy project that will allow the district to take some of the plant’s major processing units offline for maintenance without damaging the water quality. About $1.5 million has already been set aside for early planning and permitting costs, but Hubner estimates the entire project could cost upwards of $20 million.

The project, which requires approval from the California Coastal Commission, is expected to be discussed at the commission’s next meeting May 10-12. If successful, construction could start in summer 2018 and be completed by 2019.

▪  A regional water project that would recycle treated wastewater from South County cities by running it through a third level of filtration (also known as a tertiary level) so it can be injected into the Santa Maria groundwater basin.

The district’s wastewater treatment plant and a Pismo Beach treatment plant are both being considered for this water treatment process. Both could end up being selected.

It’s still in the early planning phase, but estimates placed the cost of that endeavor at $29.7 million. Once completed, up to 2,400 acre-feet of water per year — or about 782 million gallons — could be recycled, to recharge the basin. An acre-foot of water is enough to serve three average households for a year.

It’s not yet known how the district would pay for the regional water project.

Correction: A previous version of this story gave the incorrect date for when the district’s rate increase went into effect. It increased in July 2016.

Kaytlyn Leslie: 805-781-7928, @kaytyleslie

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