In key sites across the country, the items we discard today are either properly disposed of or given new life. The electrical systems and low-­voltage connections built into recycling facilities, sortation sites and collection vehicles are getting more sophisticated to make that possible.

On a basic level, the garbage and recycling process hasn’t changed much over the years. After waste is collected at the curb, it goes to either the landfill or a recycling facility. Glass, aluminum, paper and plastic goods are managed through a series of steps at  recycling sites that are becoming increasingly automated.

These sites categorize and move items toward their next process. Newly arrived material is tipped onto on a conveyor belt, which is where the processing starts, said Brandon Wright, vice president of communications and media relations for the National Waste & Recycling Association, Arlington, Va. Often, about a half-dozen people sort out what can be recycled and what can’t. These individuals put the material through the first filtering process and screen out everything from bikes and toys to Christmas lights and plastic bags from the grocery store.

An automated future

Not all tasks are done manually anymore. Before the pandemic, there were more individuals on the conveyor line sorting. Since then, companies began seeking ways to keep people from working in close proximity, Wright said. Additionally, the labor shortage is affecting many of these sites. Technology, then, is being used to help fill the labor gaps and provide precision that’s hard to accomplish manually. Although many systems run several tons of material through the recycling stream every hour, the throughput has gotten smaller due to fewer people doing the sorting.

One solution is optical sorting systems that help identify and separate paper, plastic, glass and aluminum. The precision of optics ensures that companies can better sell a pure, uncontaminated product, Wright said. 

Because of the high-quality imaging coupled with artificial intelligence (A.I.), “The latest optical systems have contributed to reducing contamination in the final product that is being sold,” he said. That can be anything from flagging a Coke bottle that’s not quite empty to a pizza box with too much grease on it.

Companies nationwide are investing, collectively, millions of dollars in sorting technology in an effort to reduce contamination. Sortation systems are being upgraded, with rubber fingers that remove cardboard and paper from the glass, plastic and aluminum material stream. That material runs through an electrical eddy current that pulls out the aluminum. Further sorting takes place optically to separate glass and plastic.

“That technology just continues to improve,” Wright said, which includes robotics leveraging A.I. to identify where different plastics should be directed.

International innovation

Sortation conveyors enable greater efficiency. Russell Conveyor and Equipment, Elkin, N.C., offers conveyors for a variety of applications including recycling sites. Norwegian technology solutions company Tomra makes sensor-based sorting hardware with optical sorting systems for metal recovery and recycling. It is being built into new and retrofit systems. With lenses inside a box to protect them from the environment, these systems track shapes and detect objects.

German company Sensotec, another global supplier for the recycling industry, offers sorting systems that can even remove small particles from the material flow. Sensotec’s systems are designed to be modular, so they can be more easily installed or reconfigured when sortation requirements change, which is something that happens often in today’s fast-moving recycling market.

Multiple security camera providers offer equipment that detects specific objects and can enable companies to collect and analyze data about the volume of processed material and when something might have gone wrong.

Many recycling companies are in transition as they upgrade their sortation and identification technology in an effort to produce cleaner products and more efficient operations.

Trends and demands

Another challenge is the varying nature of what items are being recycled and how much of that material needs to be processed. Sortation sites need to be able to meet recycling trends and demands. For instance, an increase in demand for paper over the last few years has put added pressure on some sites, while a shift to other materials is expected. Plastics that have not been recyclable before may also join the stream. This means equipment from conveyors to sensors needs to accommodate the latest material in demand.

“You’ve got these facilities that were designed for one thing or one trend, and now you know they need to be retrofitted,” Wright said. Now, companies are investing in ways to meet these changes.

Changes in landfills

Technology use is also changing at landfills. According to the U.S. Environmental Protection Agency (EPA), about 32% of U.S. trash is recycled, 12% is burned and 50% is destined for burial in landfills. Landfill facilities can be highly engineered. Some sites are collecting landfill gas and turning it into compressed natural gas or—in a few instances—even delivering the fuel for use by other customers. The goal is to be good neighbors in the communities where they operate.

In some cases, recycling companies have education centers at their sites where they host school classes and community residents can see what happens to the products they put in the recycling bin.

“What we’re creating is feedstock for another product, so there’s more transparency nowadays,” Wright said.

Emission reduction for heavy equipment

Another component of recycling and waste disposal is the large fleets of heavy equipment for transporting material. Waste disposal provider Republic Services, Phoenix, is piloting a fleet of vehicles powered by compressed natural gas (CNG). In 2019, the company announced its long-term sustainability goals that include reducing absolute Scope 1 and 2 greenhouse gas emissions 35% (from 2017 levels) by 2030. Since the company operates a natural gas fueling station at its Lower Buckeye location, it can provide the fuel needed for 19% of its 178-truck fleet serving the Phoenix metropolitan area, a Republic spokesperson said.

These initiatives have a very real emission-reduction benefit, according to the EPA, which estimates that replacing one standard gasoline-powered waste collection truck with a CNG-powered vehicle is equivalent to planting more than 600 mature trees each year.

Key concerns remain in the recycling and waste management effort to keep sites and the community safe: primarily, the proper disposal of lithium batteries. Whether or not they are detected by optical technology, these batteries can cause severe damage and health risks due to their risk of starting fires in trucks or on conveyors. Optical technology, sensor-based robotics and A.I. are all part of an effort to continue improving detection and avoiding such hazards.

As new facilities are built, the technology in use will be updated to try to anticipate the new recycling mix and make the process more accurate, sustainable and safe, and reduce costs.

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