Recycling in rural America is a huge challenge. Because of low material densities, hauling costs for recyclables are generally much more than hauling costs for municipal solid waste. Low population densities also mean that hauling distances to markets are longer, so the cost penalty for low material densities (tons per haul) is compounded by longer hauling distances.
But nine counties in South Carolina that cover 5,000 sq. mi., with a population of about 400,000 are about to be served by a new Material Recovery Facility (MRF) that the Three Rivers Solid Waste Authority (TRSWA) is opening on the grounds of the U.S. Department of Energy’s Savannah River Site. The rural counties that are served by TRSWA will be able to compact their commingled recyclables into one container so that hauling costs are reasonable, and the commingled recyclables will be separated at the MRF.
TRSWA’s unique solid waste facility has just about everything: a landfill that is making methane gas, a tire processing operation, a wood processing operation, a wood shredder which prepares wood to become wood fuel, and finally, a MRF that will not only be sorting refuse for recycling, but also will be taking a good portion of what’s left and making it into a process-engineered fuel (PEF) for gasifying.
Colin Covington, general manager of TRSWA, said there are two components to the system that will make it more profitable than the typical rural recycling system. First, the recyclables are commingled and compacted for hauling efficiencies; and, second, the MRF will produce PEF from recycling residuals rather than have these residuals go to a landfill.
All of this has been a long time coming. The construction has been drawn out over several years, according to Covington. One major challenge was how it was funded. This was done by a one dollar per ton fee that they set aside for every ton that was land-filled, consistent with the agreement with the Department of Energy. The funding has been at a level of approximately $15,000 to $18,000 per month for 12 years.
Work started on the 15,000 sq. ft. main building that now houses the MRF back in 2003. They finished it in 2004. But it was built much like a spec building because they really hadn’t laid out the rest of the process at that time, according to Covington.
“The test was building this site and structure without really knowing where we were going in the final analysis.”
But now the massive machinery contained inside the building each contributes in its own way to goals TRSWA is trying to accomplish.
Shortly after construction of the building TRSWA placed the fuel processing plant within the structure. The fuel processing plant was designed by FreeEnergy LLC of Florida, and is comprised of several modules. The first is a pre-processing vertical feed shredder, which also includes an Eidal slow speed-high torque. The next module contains a series of magnetic separators, the third module is an air classifier, followed by an eddy current separator, a high speed shredder, then another air classifier and bag-house.
The site has a metal separations module consisting of over four magnetic head pulleys that remove heavy ferrous materials.
An air classifier in the plant enables residual heavy materials to drop out and an eddy current separator is present for non-ferrous metals.
On site as well are a Powermaster high speed vertical feed shredder, a tramp materials separator with rotary lobe valve and a dust collector/baghouse for fines removal and environmental controls.
The first processing module that refuse will go to is the MRF, designed and built by Davco Steel Inc., though many components are reconditioned from equipment that TRSWA owned prior to contracting with Davco. To a large extent, the MRF is itself a recycled plant, as it’s made out of shipping containers and other previously used equipment.
The MRF consists of a 4 ft. wide by 40 ft. (1.2 by 12 m) long in-feed conveyor that drops recyclables onto a seventy foot long sort line.
Four sorters will remove non-recyclables and non-recoverables, sending them in one of two directions — either to the fuel processing line or to the landfill.
There also will be some pre-sorting on the tip floor by the skid steer operator.
After the non-recyclables are removed, there will be sorters along the remaining section to remove plastics, paper, metal and cardboard.
These sorters will drop their respective commodities into storage bins located beneath the sort line. The commodities will be conveyed to the large in-feed conveyor for the baler once volumes dictate. After recyclables have been removed, one more sorter looks to remove any remaining contaminants. Any non-compatibles will go to the landfills, and all residuals will go to the fuel processing line.
There is a third module that consists of a Cooper Equipment (manufactured in Idaho) cuber/pelletizer with associated conveyors and storage container/ metering box.
“We hope that we can sell the process-engineered fuel without densifying it with the Cooper equipment,” added Covington. “But many industrial boilers require a densified material.”
The last processing module is the baler that was purchased from Davco Steel.
The fuel processing line was bought and installed in 2003. The cuber was acquired and installed in the fall of 2006. Davco was hired in the spring of 2010 and began construction in May, finishing in September. Early in 2011 TRSWA will open its facility, which contains a collection of stations that will enhance recycling by making it more extensive and even create marketable fuel from items once thought of as waste for the landfill.
Though cranes weren’t used in the construction of the building, they were used in the setting up of the equipment. TRSWA didn’t actually run the cranes with any sort of rigging; it used private contractors to do that.
“We did have all the earthmoving equipment, though,” said Covington. “We run a large landfill and do all of our excavation and grading for the landfill. We always have. We have over 10 million dollars worth of rolling stock.”
The Three Rivers Solid Waste Authority has three Volvo articulating dump trucks that they haul in any kind of weather. They also have two large 50-ton (45 t) Euclid trucks, which they bought from a rock quarry. And as long as the weather is good, that’s the most efficient way to haul dirt, according to Covington. A Sheeps-Foot compactor is used onsite for road maintenance and compaction.
When they originally laid it out, the building was going to accommodate a sorting line set up going east-west. Now it’s going north-south. (This refers not to geographical direction but to the traditional description of how a building is referred to.) The way they’d built the building, they were going to wind up with a sorting line about 50 ft. (15 m) long; but with it now going north and south they’ll wind up with a sorting line of some 80 ft. (24 m) in length.
That extra space will be well used. TRSWA’s goal is to divert 50 percent of what is entering the landfill. Right now roughly 30 percent of the region’s materials are already being recycled and do not come to the landfill.
“We’re not going to mess with that,” said Covington. “But after doing that we’re still getting 230,000 to 250,000 tons of waste into the landfill and we think 50 percent of that is recyclable. We’re hoping to divert that 50 percent, some 125,000 tons per year, through this new system we have built through recycling as well as recovery of some as a fuel source.
“It’s been a challenge for us,” added Covington. “When you’ve only got a dollar at a time and you’re required to spend a lot more than that during construction, it can be rather complicated; it’s so much easier to plan everything and then just do it. That’s the way it came down and as it turned out, timing is everything in life and we wanted to be ready to hit the ground running. We were waiting for all the different agencies to come around to the concept of making a commodity from the residual that comes off the recycling process. “
I think that’s the whole key, the idea that it’s still part of the recycling process and it’s not a waste discard process. We didn’t know when the world was going to come around to us on that. It appears that EPA has recently documented their approval protocol through the CISWI rules just published in December 2010. It looks like that is going to give us what we have been looking for.”
They have all their permits in hand now and they are probably less than two months away from being completely finished.
“We think it will take us at least until July 1, 2011 before the plant will be in full operation because we’ve got work to do on both the front end and the back end of the whole process,” said Covington. “We’ve got to make sure material is coming into the front end in a condition that makes it compatible with the equipment — and then we’ve got to make sure we have markets on the back end. We’ve got to find people who will want to purchase what we make; our specs have got to meet their specs.”
The Aiken, South Carolina area’s Three Rivers Solid Waste Authority, is poised to become a leader in showing the country the great potential for a variety of innovative uses for waste that a landfill may have, and how connecting with the world outside the facility can make a whole lot more recycled trash. CEG
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