Single-Minded

Michael Fickes

Small towns looking for ways to control solid waste costs for citizens are turning to single-stream recycling. Penny-pinched big cities are discovering that single-stream recycling can free up labor and equipment to expand other services with no budget increase. Jurisdictions with solid waste departments operating as enterprise funds are experimenting with single-stream material recovery facilities (MRFs) and may soon begin to compete with private recycling processors.

Single-stream recycling addresses a host of problems. However, manufacturers that buy commodities from single-stream recyclers often complain of unacceptably high rates of contamination. Dual-stream customers share some of the blame for contamination problems on the assumption that they sometimes get mixed up or lazy and stuff the wrong material into the wrong bin. MRFs also are sometimes guilty of poor quality sorting.

But despite reservations manufacturers may have about single-stream recycling, haulers and consumers love it. Which means that it will very likely become the rule — if it hasn't already.

Norwood, Mass., Cuts Its Budget With Single Stream

Norwood, Mass., General Manager John Carroll could see it coming. Without a change, Houston-based Waste Management would soon raise his town's residential trash collection rates. Since the town paid Waste Management from tax receipts, a rate hike would likely require a tax increase — certain to be an unpopular undertaking.

Carroll and Assistant General Manager Bernard Cooper discussed options with Waste Management. Carroll wanted to switch from dual-stream to single-stream recycling. Having seen research that showed single stream increased recycling while reducing trash, he reasoned that less trash meant lower costs.

Under Carroll's plan, Waste Management would convert its existing MRF to single stream, pick up recyclables at curbside, sort the material and sell the commodities. The revenue would cover the collection and sorting operations. The plan also called for Waste Management to supply automated side-loading trucks for recycling and trash, 96-gallon barrels for recycling and 64-gallon barrels for trash.

It worked. “We started in October of last year, and our curbside recycling doubled,” says Cooper. “Trash tonnage has fallen.”

By reducing trash tonnage, the program exceeded its goal of holding trash collection costs steady. Norwood's annual trash collection budget fell by $200,000, from $1.9 million to $1.7 billion.

Manual Trucks Don't Bar Single Stream In Baltimore

Jurisdictions that handle their own solid waste collection don't have to buy new trucks to convert to single-stream recycling. “Our trucks are traditional low packers, operated by a driver and two laborers,” says Tonya Simmons, recycling coordinator with the Bureau of Solid Waste in Baltimore City.

Conventional wisdom says that single stream requires automated trucks and carts that work with them. Operational efficiencies will eventually pay for the new equipment. But what if you can't afford new trucks or new containers?

Baltimore couldn't. But officials decided to try single stream anyway, using the city's existing fleet of manual collection trucks. The city used mailers, fairs, festivals and television campaigns to explain and promote the switch to single stream. Residents were instructed to put recyclables into any available container and to mark it as recycling.

The city also revised its collection schedule, going from two trash pickups per week plus two recycling pickups per month to one trash and one recycling pickup per week.

It worked. Recycling tonnage rose from 11,530 in 2007 to 15,057 tons in 2008. Trash tonnage fell from 201,474 tons in 2007 to 194,121 tons in 2008. And since the altered schedule eliminated two collection runs per month, the city found itself with excess labor that could be used to expand the services provided by the Department of Public works. “We assigned the extra crews to street and alley cleaning, a service we haven't been able to provide regularly,” Simmons says.

A Tri-County Single-Stream MRF

Three counties in Wisconsin recently joined forces to build a high throughput, state-of-the-art single-stream MRF to process recycling materials. The new facility opened in July. All three counties manage solid waste collection, disposal and recycling operations as enterprise funds responsible for supporting themselves. Officials hope eventually to accept materials brought in by other public and private collection operations.

Two of the counties, Brown and Winnebago, internalize their recycling collection operations by tipping at the tri-county MRF. The third county, Outagamie, subs out recycling collections but owns and manages the MRF, which stands within the county's borders. Outagamie's contractor has been tipping recycling collections from the county's 32 communities since July.

“We all ran our own MRFs from 1993 to 2001,” says Philip P. Stecker, Outagamie's director of solid waste. “Then we signed tri-county agreements to work together on recycling. We started with dual-stream recycling. By 2007, we realized we would have to switch to single-stream collections, which residents prefer, to prevent private competitors offering single stream from cutting into our market.”

Stecker and his department studied single-stream recycling from collection through MRF design and sorting technologies and planned the changeover. “We did a procurement for a new collection contract,” Stecker says. “Previously, we invited local companies. This time, we invited national companies.”

The county eventually contracted with Inland Service Corp. of Laguna Vista, Texas, to handle trash and single-stream recycling collections. Inland was chosen because of its willingness to provide manual and semi-automated recyclable collection, allowing communities, which were responsible for buying containers, to use manual services until their budgets permitted the purchase of semi-automated carts. Bulk Handling Systems of Eugene, Ore., won the contract to provide single-stream recycling processing and sorting equipment,

So far, two Outagamie communities have come on line with recycling carts that fit Inland's semi-automated trucks. Brown and Winnebago are still delivering dual-stream recyclables, with paper source-separated from containers.

Stecker expects to be fully converted to semi-automated single-stream carts within a year. He also expects that recycling tonnage will increase as it has in virtually all communities that have made the switch to single stream. That will reduce the cost per ton to pick up and process the recyclables and put the system on a firm financial footing.

Other communities and private haulers that have asked about bringing their recyclables to the new MRF further encourage Stecker. “We haven't moved on this yet,” he says. “But we're interested. We're presently running a nine-hour shift. If we attract more tonnage, we'll have to run a longer shift or perhaps add a shift, which would create more jobs.”

In Austin, Single Stream Solves Several Solid Waste Problems

In Texas, the city of Austin's gradual conversion to automated trash collection eliminated the need for two laborers on each truck, while speeding collection and enabling the fleet to pick up trash from the city's 178,000 households in just one day per week, compared to two days a week for manual. Officials also noticed that worker's compensation injuries and costs declined as the manual trash trucks were abandoned.

Based on these observations and similar results around the country, Austin set out to automate its recycling fleet as well. The idea offered additional enticements: First, by moving from dual-stream to single-stream recycling, the city could switch to single compartment trucks. That would enable trash trucks to run recycling routes and vice versa, which would control maintenance costs by standardizing inventories and enabling larger volume discounts.

Vidal Maldonado, division manager for diversion services with Austin's Solid Waste Services Department, was asked to test the idea with a 5,000-home pilot program. The pilot supplied each household with a 60-gallon recycling cart. Residents complained right away about the size of the cart: Not enough room, they said. As the pilot proceeded, however, complaints dwindled.

The size of the carts used during the pilot program — as well as the move from split-compartment manual trucks to single-compartment automated trucks — enabled the city to pick up the recyclables once every two weeks rather than once a week.

After six months, the program ended and management told the drivers to pick up the recycling carts. But residents complained. Single-stream was so easy they didn't want to go back to dual-stream sorting. “We worked out a deal to maintain pickups for those households,” Maldonado says.

The department expanded the single-stream program across Austin, beginning in October of last year. The only change was to move up to 96-gallon carts. “In the pilot, customers often overloaded the 60-gallon carts,” Maldonado says.

The capital cost of new automated trucks didn't phase the city, Maldonado says. The department began preparing for the capital hit several years earlier by beefing up maintenance on the manual trucks and keeping them an extra year or two.

After 12 months of single-stream recycling, Austin had produced a 47.5 percent increase in recycling tonnage. Trash tonnage delivered to the landfill fell by 10,000 tons or 9.8 percent. Disposal fees dropped proportionally. Accident rates and worker's compensation costs declined. Employee turnover was limited to a couple of operators, compared to 20 percent per year under manual collection. Management slashed personnel, through attrition only, by 24 people.

What About Single Stream MRFs

Manufacturers have not taken to single-stream recycling as enthusiastically as customers and solid waste departments. The fiber is contaminated, they say. Recyclable newsprint loads come in with other kinds of paper mixed in. Glass shards often stick to the paper and damage the manufacturing equipment. HDPE containers show up mixed in with PET containers and vice versa. Manufacturers don't want to pay 100 percent of the price for a shipment that includes only 90 percent of what was ordered.

Serious problems, to be sure, but solvable, says Dick White, vice president of technology in Rutland, Vt.-based Casella Waste Systems' recycling unit. Headquartered in Charlotte, N.C., the unit covers 15 states east of the Mississippi River. “When we first started single stream in the late 1990s, the technology was new, and it did provide lower quality (contaminated) material,” he says. “Today's equipment is a great improvement.”

The Connecticut Resources Recovery Association (CRRA), a state agency responsible for providing solid waste disposal and recycling facilities, contracted with Casella to build a single-stream MRF.* White subsequently gutted CRRA’s existing dual-stream MRF in Hartford. “At 17 years old, the equipment was antiquated,” he says. “We rebuilt the plant in phases, replacing the original dual-stream lines first, while allowing for the addition of a new line to separate the single-stream collections into dual stream.”

A single-stream MRF starts processing by breaking the glass and sifting the pieces out with screens. Next, screens or puffs of air remove fiber. The plastic and metal containers from a conventional dual-stream load remain. “The key is getting a clean separation of glass and fiber from the containers,” White says.

Then the containers are sorted. Magnets pull out steel cans, and an eddy current removes aluminum containers. Optical sorters use infrared light to separate PET from HDPE based on the way the light is reflected. This technology has made single stream far more viable.

“The technology sorts plastic very precisely,” White says. “It takes a lot of capital, but it can be done. If you are generating 40,000 tons of recyclables per year, you can convert an existing dual stream plant to single stream for $6 million to $10 million, depending on the level of automation you want.”

That's the cost to redo a plant that handles 25 tons per hour. Larger volumes of, say, 80,000 to 100,000 tons per year require designs capable of 50-ton per hour throughputs at considerably greater cost.

Thus, the technology is there to give manufacturers the sort they want. The trick is paying for it.

“You have to do it right up front,” White says. “If you have a $6 million design, and another supplier suggests a $4 million design, something important is probably going to be different. And once you install a line, you will find it nearly impossible to go back and upgrade to bring up the quality of the product.”

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Michael Fickes is a Westminster, Md.-based contributing writer.

* The original text incorrectly cited the City of Hartford, Conn., as the owner of the MRF renovated by Casella Waste Systems. Normal.dotm0015Penton Media Inc.11612.00false18 pt18 pt00falsefalsefalse— Ed.

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