Single-stream recycling gains momentum

Single-stream recycling has become a common service offered by regional waste collection companies such as Casella Waste Systems and Interstate Waste Services (IWS).

The system allows residents to place recyclable materials into a single bin, leaving the sorting to specialized facilities where items are separated and prepared for reuse by manufacturers.

There were two reasons behind the efforts for single-stream recycling, says the Container Recycling Group, a nonprofit organization that serves as a leading authority on beverage container recycling and packaging waste reduction in North America.

The first was “a belief that the added convenience of not needing to sort would entice more residents to participate in their curbside programs.”

The second was and “the desire to save money by reduced collection costs. While collections costs are lower with a single-stream system, processing costs are much higher.”

While widely viewed as a convenient and environmentally friendly alternative to landfills, local industry officials say public misunderstandings about what belongs in these bins continue to create challenges.

Although guidelines vary by location and provider, materials like paper, cardboard, plastic and aluminum are generally accepted in single-stream recycling. However, not every item made from those materials can be placed in curbside bins.

“In many cases, these items are technically recyclable — such as scrap metal, film plastics, and food waste — but they are not acceptable in single-stream recycling programs,” said Jeff Weld, vice president of communications at Casella, a hauler serving the Hudson Valley and Pike County, Pa. “We do our best to separate those materials out and send them to the proper outlets for recycling, but our equipment is not designed to operate in that manner and it is important for everyone to do their part in getting the right materials to the right places.”

Scale

The scale of the issue is significant. Of the more than one million tons of material processed annually at Casella’s recycling facilities, about 12 percent is considered residual waste — items that should not have been placed in single-stream bins. While sorting systems are designed to remove these materials, some mistakes cannot be easily corrected and can undermine the recycling process altogether.

Contamination

Contamination is one of the most persistent problems. Food waste, liquids and greasy packaging can damage otherwise recyclable materials.

According to Interstate Waste Services, which serves various towns in Orange County, N.Y., excessive moisture or contamination can lead manufacturers to reject entire batches of recyclables that would otherwise have been reused.

This includes not only leftover food, but also items like unemptied bottles or grease-soaked boxes, prompting companies to urge residents to dispose of such waste through other means and reduce contamination at the source.

Safety

Safety is another major concern. Although facilities rely on advanced equipment such as optical sorters, magnets and glass breakers, human workers remain an essential part of the process.

Improperly discarded items — such as batteries, electronics, scrap metal or medical waste — can expose workers to hazardous conditions.

“Lithium-ion batteries, which have become increasingly common in everyday products, present a serious fire risk when they enter recycling facilities,” Weld said. “When this happens, workers must shut down machinery and physically remove the material, creating safety risks and operational delays.”

Other problematic items include plastic bags and “tanglers” like ropes, cables, and hoses, which can become entangled in sorting machinery and halt operations. These disruptions not only slow down processing but also increase risks for workers tasked with clearing the equipment.

Alternatives and access

To address these challenges, waste companies emphasize the importance of proper recycling practices and encourage residents to use alternative disposal options when appropriate. Local food waste programs, retail take-back initiatives and specialized recycling centers for materials like electronics or scrap metal can help ensure items are handled safely and sustainably.

Access to recycling services also varies. While some municipalities contract with companies like Casella or IWS for curbside pickup, others do not, requiring residents to arrange services independently. In addition, self-drop-off facilities — such as those operated by the Sussex County Municipal Utilities Authority in New Jersey—offer another avenue for responsibly disposing of recyclables, hazardous materials, and bulk waste, often at little to no cost.

As single-stream recycling continues to play a key role in waste management, industry leaders stress that its effectiveness depends not only on advanced sorting systems, but also on informed participation from the public.