It never made any sense.

While Napa households obsessively corralled every plastic bottle can and newspaper for their recycling bins, vast amounts of heavy demolition debris were being shipped to an out-of-county landfill.

As a result, the city's recycling rate recently dropped below the 50 percent mark required by the state.

It wasn't that most households weren't doing their darnedest to recycle, said Kevin Miller, the city's materials diversion administrator. It's just that so much heavy stuff was bypassing the recycling system, he said.

That big loophole that has been hurting the city's recycling rate in recent years is now closing. Napa's recycling rate is likely to increase by 10 to 20 percent, Miller said.

The Napa Valley Waste Management Authority has chosen a new operator for the Devlin Road Transfer Station, which collects waste from Napa, American Canyon, Vallejo and unincorporated areas in the south county for truck shipment to a landfill near Pittsburg.

The new operator, Northern Recycling Operations and Waste Services, will begin screening demolition and construction debris, as well as pickup loads from individuals, for recyclables.

The current transfer station operator, Allied Waste Inc., was recycling about 10 percent of drop-offs. Northern is guaranteeing 25 percent recycling.

When it takes over on July 1, Northern expects to hire an additional 20 employees and install outdoor screening equipment to siphon off wood, concrete, metals and plastics -- anything of bulk with recycling value, said Greg Kelley, Northern's general manager.

One of the reasons the transfer station never did much recycling is that Allied also owns the Pittsburg landfill, said Trent Cave, station manager.

"They made their money on disposal," Cave said. "There really wasn't a lot of incentive for our operator to do a lot of diversion."

It will be a different story when Northern takes over the transfer station. Northern doesn't own a landfill. It will make money from recycling, Kelley said.

It costs about $50 a ton to ship Napa throwaways to Contra Costa County, Kelley said. Every ton diverted from the landfill will help pay for the new recycling operation, he said.

In time, expanded recycling at the landfill should help to stabilize transfer station costs and thus the garbage rates paid by residents of Napa, American Canyon and Vallejo, Kelley said.

Kelley is also the general manager of Napa Recycling and Waste Services and Napa County Recycling and Waste Services, the franchise garbage companies for the city of Napa and unincorporated Napa County.

Kelley will oversee both the transfer station and the nearby Napa Recycling and Composting Facility, the city-owned facility on Levitin Way where most of Napa's recycling currently occurs.

Napa and the partnership that runs the transfer station have worked with Northern/Napa Recycling to make sure that the transfer station and the recycling/composting center "work collaboratively, not competitively," Miller said.

Residents with pure loads of dirt, yard waste, concrete, metals and tires should continue to drop materials at the facility on Levitin Way. Napa Recycling and Composting Facility charges lower rates than the transfer station for loads that have been presorted.

Northern Recycling Operations and Waste Services is owned by the same four Bay Area families that came together two years ago to bid for garbage franchises in Napa and unincorporated Napa held by Waste Management, the world's largest garbage company.

These four families have vast experience with recycling heavy materials at transfer stations in Contra Costa and Marin counties as well as at Napa Valley Disposal Services in St. Helena, Kelley said.

Napa's Bacigalupi family, formerly the owners of Napa Garbage Service, is also a partner in Napa Recycling and Northern Recycling.

Napa-Valley Waste Management Authority would like to double the size of the transfer station in the next few years, bringing the expanding recycling operation indoors, Cave said.

The authority owns 47 acres in American Canyon -- the former Oat Hill quarry for the now-closed American Canyon landfill -- that it intends to sell to finance the expansion, Cave said.