You have just finished building that new Ikea bookshelf, and you've crammed the cardboard and plastic packaging into your blue recycling bin. That's probably the last you will ever see of that trash. While your work is finished, Rob Repetto's is just beginning.

As the route manager for Petaluma Refuse and Recycling, it is Repetto's job to make sure the city's garbage and recycling leaves the curb every day. Where it goes after that depends on what is being thrown out.

"Most people have no idea where their garbage ends up," said Repetto, 49, while supervising one of his trucks on F St. in front of McNear Park recently.

A recent privatization agreement for Sonoma County's Mecham Road landfill just north of town is affecting the fate of most of the trash in the county — but not that of Petaluma, which for years has trucked all but its organic waste to a different locale.

Petaluma produces 25,000 tons of garbage and another 25,000 tons of recyclables each year. Garbage is sent to Redwood Landfill between Petaluma and Novato, where it is covered in dirt. Recyclables are dumped in a massive warehouse on Petaluma Boulevard South, loaded onto larger trucks and shipped to a sorting facility in Santa Rosa. From there, the glass, plastic, metal and paper are sold to companies across the state and around the world, according to Steve McCaffrey, government affairs director for The Ratto Group, which owns Petaluma Refuse and Recycling.

Organic waste, the stuff that goes into the green bins, is collected separately and sent to the Central Sonoma County Landfill on Mecham Road.

That landfill, just west of Cotati, is the final resting place for garbage from all other cities in Sonoma County except Petaluma. Last month, the county approved a deal to privatize the Central Landfill operations and awarded Arizona-based Republic Services a 20-year contract worth $547 million.The deal is expected to expand the landfill as more cities commit their garbage to it.

Despite the changes there, Petaluma's non-organic garbage will continue to travel south to Redwood Landfill because the rates to dump garbage there — known as tipping fees — are cheaper, said Dan St. John, the city's public works director.

"If you look at the tipping fees, it's really quite astounding," he said. "It's really a price-sensitive business. If the city were to go to the Central Landfill, garbage rates would go up considerably."

Since 2006, Petaluma has transported its waste to the Redwood Landfill using split-body trucks, which are able to carry recyclables and garbage in separate compartments. The split-body trucks make collecting much more efficient, and each truck can hit about 800 residences per day, Repetto said.

The recyclables, meanwhile, are sent around the state and even abroad for reuse.

Recycled glass is used in California's wine industry. Plastics are shipped to China where they are made into everything from toys to synthetic filling for jackets. Paper gets pulped and turned into newsprint and material for cardboard boxes.

"A very important part of what we do is minimize what we send to the landfill," McCaffrey said.

As the city prepared to sign an extended contract with the company in 2012, there was some concern among councilmembers that the company had not diverted as much waste from the landfill as it had promised when it took over operations from GreenWaste in 2010.

But St. John said recently that the city is happy with its garbage contract, worth $10 million annually. The 15-year extension signed last year provides the city an additional $750,000 annually.

"It seems to be a good partnership with the city," St. John said. "We can't complain about their level of service. They do a darn good job. There's a lot more to it than having someone haul your garbage away and dump some dirt on it."

(Contact Matt Brown at argus@arguscourier.com)