Single-Bin Scenarios

The practice of processing municipal solid waste (MSW) to “mine” or extract recyclables is an area of focus for a number of facilities both new and old in North America.

Sometimes referred to as “dirty MRFs,” these facilities set up to recover recyclables from garbage were first built some 20 to 30 years ago, particularly in Southern California. A few examples include Athens Services in City of Industry, Calif.; CR&R Waste & Recycling Services in Stanton, Calif., and the Medina County Central Processing Facility in Seville, Ohio.

Since then, the growth and development of curbside or source-separated recycling programs may have overshadowed the concept of solid waste processing, but this practice certainly has not been abandoned. In fact, advocates say it may be increasingly feasible, at least on some level, for many waste streams in the years to come. As they explain, the newest incarnations of the concept have evolved from their predecessors.

Today’s MSW processing operations are not without their challenges. But they have apparently overcome some obstacles by exploiting nearby single-stream and wet-line setups, targeting specific waste streams or relying on the presence of downstream conversion technologies to maximize their cost-benefit ratio.

30,000-Foot View
Joe Sloan, founder of Sloan Vazquez LLC, Irvine, Calif., a waste and recycling industry consulting firm, says processing solid waste can make sense depending on the infrastructure already in place within a municipality. He also argues that the dirty-MRF philosophy makes economic sense from a combined collection-processing vantage point, requiring fewer trucks to pick up the same amount of material.

“The resistance to dirty MRFing always had to do with the fact that it wasn’t politically correct,” says Sloan. “It didn’t make the generator have to live with their trash and think about their disposal habits.”

Sloan says that while a one-collection concept may result in a bit more contamination of recyclables, it also results in equal or greater recovery than source-separated materials.

“The more and more people start to focus on carbon emissions and air quality and fossil fuel use and even economics,” he adds, “I think the more and more you’re going to see these programs move toward the single-source dirty-MRF type of process.”

Sloan refers to Republic Services Inc.’s Newby Island Resource Recovery Park in San Jose, Calif., as perhaps the most recent example. The facility, opened in 2012, is processing all of the city of San Jose’s commercial waste through some combination of source-separated processing and municipal solid waste (MSW) processing.

That California should be home to pioneers in this area isn’t surprising: The state has called for a diversion rate in excess of 50 percent, says Emily Hanson, director of business development and communications for another San Jose facility, Greenwaste Recovery Inc. That diversion target, she says, is moving to 75 percent by 2020.

Fortunately for Greenwaste Recovery, it is well on its way to meeting that goal. The company now is achieving diversion rates of between 72 and 75 percent on its MSW, or wet, line at the company’s MRF, which began operations in 2008. The facility has a single-stream processing line alongside its MSW line, Hanson says.

One reason the company is able to achieve such high rates, Hanson explains, is because organic materials recovered on the MSW line are sent to Greenwaste’s sister company, Zanker Road Resource Management Ltd., which operates the Z-Best Composting Facility, located about 35 miles to the south.

Hanson says each municipality’s materials stream is unique; however, the lion’s share of garbage Greenwaste processes comes from multifamily dwellings in San Jose. Having the single-stream and MSW lines in proximity is a key benefit for the process. She explains that when MSW enters the facility, it goes through a presort process to remove large recyclables. Bags are broken open and sent through four manual sorting stations. Those recyclables are then moved to the single-stream line for further processing, Hanson says. “Rather than needing to have a whole other way to process those recyclables, we already have the line right next door.”

For a few other communities, Hanson says, the company has set up a three-stream curbside collection system that is collected with one split-loaded truck: one side for compostables plus garbage, the other for recyclables.

“The reality is, we are using a wet-dry system,” Hanson explains. Sorted recyclables are processed on the recycling line, while the mixed garbage and compostables go to the MSW line.

The system is apparently working. The community of Los Altos Hills recently achieved an overall recovery rate of better than 98 percent, Hanson says.

However, she says, Greenwaste does not advocate a one-container system, which would erode the value and cleanliness of the recyclables. “By keeping the dry material separate from the wet material, we preserve the integrity of all the commodities,” Hanson says.

She says MSW processing can work in every community, as long as there’s political commitment, conscientious residents, capable haulers and processors and tolerance for its higher cost. “It’s so much cheaper to landfill.”

A Dry Waste Approach
With the wide adoption of residential source-separation programs throughout the country, Sloan says, processing MSW may not be necessary in all areas. However, in many cases, he says, it can provide an add-on opportunity.

“What people are now doing is looking to see how they can go further,” Sloan says, in some cases adding a MSW processing component to what is already in place.

That’s similar to the tack taken by Canada Fibers Ltd., Toronto. One of the company’s six plants (a seventh is soon to open) is processing industrial, commercial and institutional waste (IC&I). The lines, installed in 2010, can handle about 110 tons per year.

Jake Westerhof, vice president of operations for Canada Fibers, says the company has worked with its haulers and certain accounts, such as manufacturing facilities, retail locations or warehouse operations, to target appropriate dry IC&I streams. The dry waste ideally does not contain food or compostables, Westerhof says, as the facility is neither set up nor licensed to take organic material. The company is also processing residual materials from other MRFs.

Westerhof says in the 18 months Canada Fibers has offered ICI processing, there have been challenges, such as receiving organics mixed in with the dry waste. However, the primary challenge, Westerhof says, is economic.

“We have to compete with a very inexpensive disposal option,” he says, particularly in the absence of regulations mandating recovery.

Still, Westerhof says he believes the dry waste approach is the way to go, particularly for ICI streams. “Before anything goes to a landfill, it should run through a system like this to recover those secondary resources and materials that are in there.”

Westerhof says that while the residential diversion rates in the region are already reasonably high—around 60 percent or better in many municipalities—the ICI side needs to catch up. He says the majority of this waste stream—as much as 80 percent—is generated by small to medium-sized operations that may not be recycling in light of the cost.

On a Small Scale
Steve Viny, CEO of Envision Holdings, has witnessed the benefits of MSW processing for years. His company built the Medina County Central Processing Facility in Seville, Ohio, some 20 years ago, and it continues to operate today.

More recently, Envision was involved in the joint venture between its sister company, PRFection Engineering, and Novelis, based in Atlanta, creating MiniMRF LLC in 2008. The company manufactures the MiniMRF technology, a compact recovery plant comprising three modules that processes garbage and turns out recyclables and compostables. The system was offered to the market after a two-year internal operation phase, and Viny says a number of projects are now underway.

“You can think of it as the MRF of last resort,” he says. “There’s still a lot of gold left in the waste stream, and that’s what we seek to recover with the MiniMRF.”

Viny says the MiniMRF can handle up to 25 tons per hour. Each of the three modules measures 8 feet wide and 53 feet long and can be arranged in various configurations.

The base model produces three fractions: organic, ferrous and nonferrous. Users can opt for an engineered fuel module to produce boiler or kiln fuel or they can add near infrared modules to separate paper and plastics. “It’s just a matter of what your goals are and how much cap-ex you want to devote to the project,” Viny says.

He adds that the MiniMRF is ideal as a front-end sorting system for facilities with some type of energy conversion technology downstream. “We have been contacted by a number of people who have gasification and pyrolysis technology and what they typically don’t have is front-end sorting. So, when they look at the MiniMRF and see what it does and the price point, they’re pretty awed.”

While it’s clear the newest MSW processing models aren’t warranted for all areas, many communities have shown that synergies can be achieved with existing systems. From a practical point of view, the cost-comparisons can be compelling, Sloan says. When measuring the resources consumed by source separation and single-stream processing against those required for MSW processing, he says, “you get a good result from that, and you accomplish it with less resource consumption.”

The author is a managing editor with the Recycling Today Media Group and can be contacted at lmckenna@gie.net.