One-compartment trucks zoom through neighborhoods, emptying big blue bins full of recyclables. No sorting required—residents stuff all their paper, glass, and cans into the same bin. Northern California counties that switched to collecting combined recyclables, called single-stream, have seen their tonnage increase by an average of 30 percent—some cities, like Sonoma County’s Windsor, recorded a jump of 70 percent.
The method, pioneered in Southern California in the late ’80s, comes with another plus: it costs less. According to sorting equipment manufacturer Erik H. Eenkema van Dijk, during Sacramento’s trial program, collection man-hours were reduced by nearly half and total annual costs dropped 10 percent. Los Angeles cut its collection costs by a quarter while diversion rates went up 140 percent. To cash-strapped cities trying to meet the state-mandated waste reduction rate of 50 percent, single-streaming is a boon. And since the mid-’90s, the stream has become a flood: in California, most large cities have switched to single-stream or are in the process of switching.
Downstream, the picture is not so rosy.
Paper represents from 70 to 80 percent of recycling tonnage—and unlike plastics, it can be reused eight to ten times over as office paper, tissue, or packaging. But in a single-stream system, broken glass often becomes mixed in with the paper. Shards can injure workers at sorting stations or at paper mills that handle recycled paper; pieces of glass as fine as sand can lodge in sensitive gears in mill machines. Some mills have stopped accepting recycled paper from municipalities that use single-stream collection, while others buy only from cities whose sorting systems produce the cleanest bales.
In a March 2003 study of single-streaming conducted by San Francisco-based paper recycling advocacy group Conservatree, executive director Susan Kinsella writes, “Single-stream collection requires us to rethink why we’re recycling at all.” She was surprised at the extent collectors and cities, faced with growing pressure to divert more residential waste away from landfills, dismiss problems at paper mills: “Over and over, local government people told us, ‘Diversion is the only thing that matters to us.’” Kinsella contends that collectors made a unilateral decision. “Many seem to no longer be concerned about the fact that it’s not working for many of the manufacturers nor for producing a significant segment of high quality recycled products that purchasers would trust.” Kinsella says, “I understand diversion to be a strategy. But what’s happened is that it’s become the only goal.”
Diversion rates can play tricks. Kinsella’s report says that Canadian and US mill representatives complain that up to 20 percent of single-streamed paper is so contaminated it ends up in a dump. When Eureka Recycling in St. Paul, Minnesota, conducted a study in 2001, the company found that 1 to 5 percent of source-separated material had to be dumped, versus 15 to 27 percent of single-stream material.
Much of the West Coast’s paper is sold to mills in China. Newer Chinese mills don’t have sorting lines where glass is removed by hand, and manufacturers there are disturbed enough by the increase in glass-contaminated paper from the US that they’ve increased purchases of lower-grade fiber from Japan.
Yet switching to single-stream often permits collection of other classes of materials. “We’re co-collecting garbage and recyclables in a split truck,” says San Francisco recycling program manager Bob Besso. “In the second truck, we collect food waste and yard waste. So we’ve put two trucks back on, but we’re collecting three streams instead of two.” Besso says the primary motivation for switching was to raise the diversion rate, which has gone up 20 percent. “We’ve exceeded 50 percent, but San Francisco has a 75 percent goal for 2010 and 100 percent by 2020.” Most of the increase was in organics, of which Besso’s food-waste collection is the first in the nation—some 300 tons of food scraps daily are turned into finished compost sold to golf courses, farms, and vineyards.
Kinsella, who attended a September paper industry convention in Washington, DC, says mill operators are grudgingly accepting that they must change their own process to deal with single-streamed bales. But Kinsella advocates adding two more streams to single-stream: glass and office paper, which loses much of its recyclability when mixed with other paper. She notes that there is equipment that can sort out grades of paper, but it’s costly: “Why would you mix it up and pay more to separate it when it should have started out separated to begin with?”
