SINGLE STREAM IS PROBABLY the hottest topic in recycling. It's also one of the oldest. Back in the mid '70s, curbside recycling programs were single stream because they only collected newspapers. Just like today, some end-markets complained that curbside recycling produced a nasty contaminant. Back then, “rotogravure” papers were the bad guy. If you forgot, those are the Sunday supplements. Deinking mills insisted that the slicker paper created serious problems with recycling systems. In response, processing plants learned how to pull out the slickies and produce a pack that met specifications.

Today, single stream means one collection container for all paper, glass, metal and plastic recyclables. The materials are then separated and processed at a MRF and sold to end-markets.

Single stream's popularity is fueled by the need to meet high diversion goals and cost considerations. Most people find putting everything in one container easier than using different bins for two or more materials.

Making recycling less expensive is always important. Because collecting recyclables is curbside's biggest expense, gathering materials in one container, instead of several, leads to lower collection costs. Even though processing costs are higher, the collection savings mean lower overall costs. But when quantity and quality butt heads, does something have to give?

The fuss comes from paper mills that complain that mixing glass and plastic with paper creates problems they must pay to fix. Glass embedded in paper abrades plant equipment. A recent study claims that paper mills receiving single stream materials have excessive disposal costs for plastic bags and newspaper sleeves mixed in with the paper.

At this year's National Recycling Congress, a paper company representative at the single stream session presented data showing higher levels of contamination in paper when his mills bought from single stream MRFs. He has a right to be concerned. End-markets make products from raw materials that meet quality specifications.

Some people say a paper mill should just reject off-spec material. But when a mill is scrambling for raw material, it will take what it doesn't want just to keep its paper-making machines running. And it will pray the “bads” don't cause serious problems.

But maybe the problem isn't single stream collection. More likely, it's processors who fail to deliver a quality pack. At a recent meeting in Washington, a representative of a newspaper deinking company said his company buys deink-quality old newspaper from a single stream MRF. He added that some single stream processors can meet his company's rigorous specs and some cannot. His company buys from those that can.

That's the key to single stream. Technological advances in processing allow MRFs to meet quality specs. These advanced MRFs may mean fewer “10-fingered pickers” but are part of recycling's industrial revolution. Once again, machines replace humans.

Processors are making tremendous technological strides to meet specs. If they can produce the raw materials end-markets want, then we will have quality and quantity. If not, recycling is in for a rough ride.

Opinions in this column do not necessarily reflect the National Solid Wastes Management Association or the Environmental Industry Associations. E-mail the author at: cmiller@envasns.org

The columnist is state programs director for the Environmental Industry Associations, Washington, D.C.