One can or two?

Trash day in Placer County is a singular event.

When it’s time for collection, residents of Roseville and the surrounding cities toss all of their household waste—that’s your usual garbage as well as soda cans, cardboard and plastic containers—into just one curbside can instead of two.

Haulers take that garbage-recycling soup to the county’s materials recovery facility, where a massive series of interconnected conveyor belts, chutes and discs do the dirty work of sorting the recyclable from the wrecked. Trained workers then pluck the resalable materials from 2,000 tons of garbage dumped at the facility each day.

In most cities, the amount of recycling diverted from landfills depends on the voluntary compliance of its residents.

“By having it all in a single bin, we have 100 percent participation,” said civil engineer Eric Oddo, who is in charge of operations at the MRF.

The MRF has been the cornerstone of Placer County’s waste-management programs since 1995. Legislation enacted in 1989 called for all counties in California to reach a 50 percent solid-waste diversion rate by 2000. The city of Roseville recently reached a 66 percent diversion rate with the help of the single-bin system.

“The MRF system allows us to capture both the residential and commercial waste streams,” said Roseville administrative analyst Sean Bigley. “Many multibin systems capture recyclables from the residential stream only.”

Oddo likened sorting garbage to mining for gold.

“Granted, it’s just trash, but there’s some good stuff in there,” he said, toeing a deflated basketball planted in a heap of trash that included an aerosol can and a three-legged patio chair.

A 1-ton bale of aluminum, for example, currently sells for $4,000 to $5,000; several rows of tightly packed bales line the warehouse floor. Besides glass, aluminum, paper, and cardboard, workers routinely pull out marketable scrap steel, copper and large mixed plastics. That seemingly worthless plastic patio chair can be sold to manufacturers and used to construct railroad ties.

A single-bin approach eliminates the need to educate the public whenever a certain type of material becomes valuable, Oddo explained. Instead, workers are trained to rescue recyclable items rushing by on conveyor belts.

The eagle-eyed sorters frequently remove hazardous items such as batteries, paint cans, and fluorescent-light tubes, preventing these items from ending up in the nearby landfill. The facility pays to have the hazardous materials removed.

The downside of the mining aspect is, as marketability of certain items decreases, more of it may end up in the landfill, provided overall diversion goals are still being met. To those who strive for “zero waste,” single-stream waste management represents another trade-off.

“The single-stream approach gets more participation, and source separation gets a higher-quality resource,” said Northern California recycling advocate and director of operations at Berkeley’s Urban Ore, Mary Lou Van Deventer. The organization’s mission is to end the age of waste by advocating and developing total recycling, and Van Deventer is definitely skeptical when it comes to the single-waste stream.

“Any time you mix resources together that are unlike, you are downgrading them for usability and salability,” said Van Deventer.

Paper fiber spiked with glass shards, for example, damages machines used to make new paper and is therefore less desirable to buyers. Glass shards removed at paper plants can also end up back in the landfill.

From a city-management standpoint, the single-bin system provides financial benefits that help keep utility costs low.

“First, the volume of routes we have to maintain is much less than what a multibin system would require,” said Bigley. “That means lower staff costs, less capital expenditures on vehicles and less vehicle maintenance.”

Plastic bags and Styrofoam continue to end up in the landfill, but that may soon change as technologies for converting waste into energy are developed and become more efficient. Grocery bags, for example, can be used to produce diesel fuel, and scrap wood can be burned for electricity.

“We’re on the cusp of a huge shift in how we handle solid waste,” Oddo said. “That’s the future.”