Density required

Expanded and extruded polystyrene foam has been used in a variety of applications for several decades, and for nearly as long recycling advocates have tried to explore methods to recycle the material.

Extruded polystyrene foam is used in some building product and packaging applications, while expanded polystyrene (EPS) is used as packaging in numerous ways as well as in food service applications.

Polystyrene foam is among the most lightweight materials available, with even large chunks of foam barely measurable on a floor scale. If a scrap generator or a recycler is putting together a weighty enough load of polystyrene to book a truck or shipping container, considerable densification is going to be necessary.
 

Where it's at

At least as much as with other recyclable materials, significant amounts of polystyrene must be gathered in one spot to achieve enough scale to make a truck driver’s time and fuel worthwhile.

Among the places where generous volumes of foam can be found in a single location are large retail locations, distribution centers and warehouses and manufacturing and assembly plants.

Some of these polystyrene foam scrap generators are managed by companies with increasingly aggressive landfill diversion, recycling and sustainability goals, says Susmit Mahalanabis, material marketing specialist with Toronto-based Cascades Recovery Inc.

“There has been a level of awareness at the corporate level, and the ‘big box’ stores do try to improve their recycling scorecard by including polystyrene foam,” he remarks.

Mahalanabis lists large retailers, “especially furniture and electronics retailers,” as among those striving to recycle plastic foam packaging.

Recycling advocates and municipal recycling officials seeking to build bigger programs also have begun to target polystyrene foam as a product to recycle, though operators of municipal material recovery facilities (MRFs) largely say the material is unsuitable for their automated sorting processes. (See the sidebar “Thanks but no thanks”)

The lightweight plastic is difficult to isolate when commingled and may travel along with newspapers atop the initial set of screens. As well, because the material is so light, even if it can be separated, accumulating mass from the residential stream stretches along a lengthy timeline.

The majority of polystyrene recycling taking place is thus tied in to larger-scale generators, with densification occurring at or near the point of generation.

“We have seen interest in foam recycling from a number of sectors, including retail and manufacturing,” says Rich Simon, corporate recycling marketing specialist with Rumpke Consolidated Cos. Inc., Cincinnati. “With the exception of some very specific generators, what we often find is a wide range of actual foam types in a customer’s waste stream, with EPS being just one of many types of foam (along with polyethylene foam, polypropylene foam, polyurethane foam, etc.). But the interest and desire to find landfill alternatives for these materials is nearly universal.”
 

Squeeze hard

Warehouse managers and others willing to prepare polystyrene scrap for shipping and recycling generally understand the need to densify the material quickly to prevent the accumulation of large piles of white polystyrene foam.

Gregory J. Leon, vice president of sales at RiverRoad Waste Solutions Inc., Tinton Falls, N.J., says not every generator of foam scrap bales it on site. “Some manufacturers will park a trailer at a dock to load trailers [loose] for recycling,” he comments.

Simon does not see that scenario panning out very often. “Depending on location, and access to markets, storing and shipping this material in loose form is often not an economically sustainable avenue for recycling. In addition to the inherent light weight of the material, such scenarios require on-site separation and transportation to an accepting facility, where the value of the material in the loose form is marginal at best.”

At sites where foam generation quickly adds up, densification may soon make sense, says Leon. “Other companies will invest in a densifier,” he comments. “The material is compressed to an approximate 50:1 ratio. Not only does this save valuable floor space and Dumpster space, but the resulting cube or cow pie-shaped material may now be commoditized.”

Mahalanabis has witnessed the same trend among Cascades’ corporate customers. “In many instances, retailers have installed densifiers in their distribution centers,” he says. “Polystyrene foams are densified to increase the weight-to-volume ratio [before] the densified polystyrene is purchased by plastics recyclers.”

Phil Plotts of Foam Equipment & Consulting Co., St. Louis, says specialized units such as those distributed by his company may be necessary to produce the desired density. “Generally, balers made for cardboard cannot create enough pressure on the polystyrene foam to compress the material,” he says. “I have heard people state they were able to achieve trailer load weights of 6,000 to 8,000 pounds with baled foam. A compactor (some manufacturers refer to them as a densifier) made specifically for foam compression [can] produce logs or blocks with high enough density to achieve 40,000-pound trailer loads,” says Plotts.

Tiger brand compactors sold by Plotts are manufactured by Heger GmbH & Co. KG of Herrenberg, Germany. Foam Equipment & Consulting markets the units as having small footprints, with the smallest model less than 2 feet wide by less than 9 feet long.

Heger says its larger Tiger 300B model can deliver a volume reduction of up to 90 percent. “The extreme reduction in volume achieved (in the ratio of 40:1) not only produces a considerable saving in transport and disposal costs, but the blocks produced can be also recycled as raw material,” according to the company’s website, www.heger-recycling.de.

Leon says many of RiverRoad’s corporate customers are seeking that very outcome. “It is a diversion win, a trash cost reducer and a revenue opportunity,” he says of baling or compacting polystyrene scrap on site.

Regarding the range of balers and compactors available to accomplish this task, Leon says he is seeing a preference for smaller models among customers. “These same space constraints [that create customer interest in polystyrene baling] can also mean they would prefer a baling or compacting unit with a smaller footprint in order to keep the polystyrene recycling operation off in a relatively small corner of their facility.”

That is not to say the practice will work in the case of every generator, Simon points out. “There are inherent challenges for recycling EPS foam [involving] storage and transportation,” he says. “With the exception of some very specific generators, on-site densification equipment may not be an economically sustainable option. When all equipment, storage and shipping cost factors are considered, the cost basis per ton may significantly outweigh traditional disposal means.”

Thus, a desire by the foam scrap generator to avoid the landfill may be a necessary prerequisite.
 

Shaped up and shipped out

For any polystyrene foam recycling operation to make sense, one or more reliable end markets with a reasonable shipping cost structure will be needed.

Recyclers contacted for this story say such markets have been developing as the available volume of recycled foam increases. In most cases, these buyers want the foam shipped to them in baled or compacted form.

“There are North American consumers in some regions,” says Mahalanabis. “The densified polystyrene is purchased by plastics recyclers in North America or overseas,” he adds.

From his view at Rumpke in the Midwest, Simon is encouraged by some of the end market activity he has been seeing. “There is a readily available market for densified EPS foam in our area,” he comments. Buyers wish to purchase it “in 30,000-pound-plus truckloads,” he adds.

Densifying the material is critical, though, adds Simon. “Facilities accepting loose EPS foam for recycling are less readily available throughout our region and [are] typically found only in larger metropolitan areas,” he notes.

If the right combination of corporate sustainability, landfill diversion and reachable end markets are in place, baling polystyrene foam may continue to gain ground as a recycling practice in North America.

The author is editor of Recycling Today and can be contacted at btaylor@gie.net.