Correction: An earlier version of this story should have said the Los Osos wastewater treatment plant will produce about 700,000 gallons of reclaimed water per day.

The Los Osos sewage pipeline project was completed in May — and now the county is in the midst of building a $48 million treatment plant for the system.

On Tuesday, about 40 workers scurried around the site on Los Osos Valley Road, operating massive cranes used to set concrete around rebar frames and laying the route for a paved road to the site.

The plant, situated just east of town and next to the Los Osos Valley Memorial Park cemetery, will cover 12 acres of a 24.5-acre site when it’s completed in 2016.

County project manager John Waddell said construction is about 20 percent done. Sacramento-based Auburn Constructors was awarded the contract for the job.

“We’re still a couple of years away from connecting people,” Waddell said. “But we’re going to start the public outreach campaign at the beginning of the year on what people need to do to hook up at their homes.”

Mostly tucked away from public view at the northeast corner of the site, workers are busy assembling the 15- to 20-foot walls of two large treatment basins that will process more than 2 million gallons of wastewater per day.

When the project is completed, the effluent will be channeled in a circular motion through the basins while microorganisms break down the sewage.

The wastewater then will be funneled into smaller tanks for further filtration and then disinfected under ultraviolet lights.

The entire process creates water clean enough to irrigate parks, golf courses and schools. However, the reusable water isn’t drinkable.

“We plan to produce about 700,000 gallons of reclaimed water per day with a demand of hopefully more than a million gallons (for irrigation),” Waddell said.

The plant will be able to adjust to handle heavy sewage flow days such as Super Bowl Sunday and Thanksgiving.

The current work is primarily focused on grading, installing underground piping and building the underground treatment basins.

Four buildings are yet to be built: electrical, administrative, maintenance and a dewatering facility that separates water from sludge.

Construction is expected to continue through March 2016, when the facility will be ready for sewer connections with approximately 4,800 properties in Los Osos.

Homeowners will be required to pay between $2,000 and $10,000 to install lateral pipelines from their homes to the street lines.

Waddell estimates the average cost will be about $2,000 to $3,000 per household. Los Osos residents then will start paying a $160 per month assessment once the facility starts its operations.