“The greatest economic benefit of recycling is that it provides a base of materials for robust, efficient manufacturing industries. So far this decade, US paper manufacturers have voluntarily built more than 45 recycling-based pulp and paper mills and only a handful that use virgin wood. This is not just because recycling plants are better for the environment, but because they are a less expensive way to increase production, taking advantage of the increasing supplies of used paper collected in business and community recycling programs.” – Richard A. Denison & John F. Ruston
The average American throws away almost 4.4 pounds of waste each day. That is equivalent to over 1,600 pounds (more than three-quarters of a ton) each year. In 2012 (the last year we have reliable figures from the EPA) America as a whole generated about 250.9 million tons of waste. Of this amount, we recycled and composted 86.6 tons, or approximately 34.5%. While recycling more than one-third of our waste may sound impressive, it is a long way to go to the ultimate goal of 100% recycling and zero waste. So what stands in the way of maximizing our waste recycling efforts?
First is the heterogeneous nature of the wastestream itself. This is an internal factor that complicates any waste extraction and sorting process. According to the EPA (2012 data), waste consisted of the following categories: “… newspaper/mechanical papers recovery was about 70% (5.9 million tons), and about 58% of yard trimmings were recovered. Organic materials continue to be the largest component of MSW. Paper and paperboard account for 28% and yard trimmings and foodwaste account for another 28%. Plastics comprise about 13%; metals make up 9%; and rubber, leather, and textiles account for 8%. Wood follows at around 6% and glass at 5%. Other miscellaneous wastes make up approximately 3% of the MSW generated in 2011.”
To achieve high levels of waste recycling, widespread adoption of methods and machinery allowing for the processing of this diverse waste stream at industrial scales are necessary.
“Dirty MRFs” accept single streams of commingled waste that has not been prepared or presorted.
In addition to the variety of the wastestream itself, individual objects can be difficult to recycle due to their composite makeup. This is especially true of “composite packaging,” which consists of more than one material (e.g., drink cartons that use a layer of aluminum sandwiched between layers of plastic and paper as a smell and taste barrier). These laminated containers consist of approximately 5% aluminum foil, 20% plastic and 75% paper by weight. Such hybrid material can be nearly impossible to economically separate out into its basic components. Fortunately, these materials make up a relatively small percentage of the overall wastestream. However, this problem exists in some degree for most recyclable materials (such as metal cans, glass, or plastic jars with glued-on paper labels and plastic or metal lids).
Beyond internal factors, such as the physical characteristics of the wastestream, external obstacles to recycling can prevent a community from achieving zero waste. These external factors include the lack of a viable market for recycled materials, insufficient number and throughput capacity of recycling facilities.
First, there is not much point to recycling, no matter how efficient and complete the process of material recovery, if there is no market for recycled materials. This was apparent after the economic crash of 2008 and the subsequent collapse in prices for recycled materials on the scrap market. During the first and worst part of the economic downturn, recycled materials were often put into stockpiles for extended periods due to lack of buyers. A major market for American recyclables was and remains Chinese industry. However, Chinese demand for American scrap has not fully recovered to its pre-2008 peak. This illustrates the need to develop a more diversified customer base with expanded local and regional markets for recycled materials. Key to developing these markets is overcoming the perception that recycled materials are of higher price and lower quality than those made from virgin materials. This can be achieved by large-scale processing, which provides economics of scale and allows adherence to strict quality specifications.
The second external restriction is the bottleneck that develops from a lack of collection and processing facilities, or insufficient throughput capacity of existing facilities. Recyclers are in business to make money, too. And new or expanding processing plants require investment-and investors require a return on their investment. The question is, then, what sort of facility meets the need for managing a diversified wastestream (allowing for recovery of all but the most complicated waste objects), while ensuring the low price and high quality needed to developed markets?
The answer is the materials recovery facility (MRF). But what kind of MRF? There are two basic types, single-stream and multistream, and they have their own unique advantages and disadvantages.
A multistream MRF performs material recovery, not sorting and separation. That is already performed by the households and businesses that separate recyclable materials at their individual locations. These are separated into individual bins and containers for pick up and shipment to the multistream MRF. Each of these separate sources of recycled waste forms a stream in the multiple streams of materials being sent to the MRF. Since the materials arrive neatly, in unseparated condition, the multistream MRF is often referred to as a “clean” MRF.
Once each presegregated load of waste arrives at a multistream MRF, it is processed into subcategories of individual waste materials. A fairly typical approach to multistream MRF design assumes the initial acceptance of three broad categories of segregated waste: commingled containers, paper products, and unrecyclable waste. This last category is not processed and may by pass the MRF altogether, going directly to a landfill.
The other two categories get sent to separate sorting stations, where individual items are separated largely by hand. This is a task made much easier by the presorting done by the households and businesses participating in the program. The commingled containers are separated into plastics (PET and HDPE), aluminum cans, and ferrous or tin cans. The paper products get separated into corrugated cardboard, newsprint, magazines, and mixed office paper. In both cases, marginal materials and residues are put in disposal bins for shipment to the landfill. And that is the great strength of the multistream approach, the ability of the laborers to use common sense (something no machine has) when making sorting decisions and maximizing the quality of the recycled materials.
However, multistream MRFs won’t work at all without public participation. Public participation in the process is a necessary first step and the participation rate depends on educating the public on the need for recycling and motivating the public to be willing to participate. Households and businesses must be provided information on what components are recovered and marketed. This will increase both the quantity and quality of the recovered material.
So what makes a single-stream MRF different than a multistream MRF? As a multistream MRF is referred to as a “clean” MRF, a single-stream MRF is usually called a “dirty” MRF. This type of MRF accepts a single stream of commingled waste that has not been prepared or presorted. Instead of labor, the multistream MRF relies mostly on machinery to separate waste components based on magnetic properties, size, shape, weight, and color. The machines have been designed to handle the anticipated characteristics of the incoming wastestream.
The first stage of a multistream MRF operation begins with the extraction of ferrous metals. This is accomplished with simple magnetic separation. The next step is to remove nonferrous metals (such as aluminum) by means of eddy-current separators. These mechanisms use rapidly rotating magnets that induce a current (and thus an opposing magnetic field) in the metal, causing it to literally jump into an awaiting bin. The remaining waste is removed according to its size and weight characteristics. The remaining wastestream passes through a disc screener, which creates a wave action in the waste by means of rotating discs of various sizes and shapes set in the screeners floor. This wave action caries large light objects (such as cardboard boxes) to the top of the stream for easy removal. Such large, heavy objects as refrigerators, car parts, or couches are usually removed early in the process by means of bulk handling systems. Rotating trommels (spinning drums with perforations in their sidewalls) are used to remove small, heavy objects. Such small, light objects as mixed paper are removed by means of air pressure applied by clarifiers and air knives. The remaining residue has a high percentage of colored glass and plastics. These can be sorted according to color by means of light spectrophotometry and optical sensors.
A relatively new development in multistream MRF processing design is the “wet” MRF. The wet MRF utilizes new mechanical and biological treatment techniques whose application results in increased density, separating out absorbent portions of the waste and resulting in a cleaned output stream. The high-pressure water streams hydrocrush and dissolve organic and biological materials. The wet residue is then sent to anaerobic digesters while the remaining inorganic waste solids are removed for recycling.
The greatest advantage of the single-stream MRF is its ease of use. By investing in capital instead of labor, operators of these MRFs achieve higher processing rates at a lower cost. The need to educate and motivate the public s minimal since their active participation is not really required. Homeowners need only put their trash out on the curb for pickup, same as always. The MRF separates and recycles the waste when it arrives. Given these factors of cost, productivity, and convenience, the overall market trend is towards large sale, single-stream MRFs managing waste flows from regional waste collection efforts. Multistream MRFs still exist to serve local niche markets.
MRF Equipment Suppliers
Amut Ecotech S.R.L. is a leader in plastic manufacturing that provides machines and services that complete the process of making sustainable packaging via resource recovery. The company’s Model SBS 201 is a single-stage ballistic separator. As a hook-lift ballistic separator, this equipment is designed to maximize production of three extraction streams: flat fraction, rolling fraction, and sieved fraction (fines). The sieved fraction represents material of little or no value that would be returned to the landfill and consists of mixed materials having sizes that allow it the pass through the holes of the blades. The flat fraction consists mainly of polyethylene film, domestic collection bags, soft packages, paper, and cardboard. The rolling fraction is made up of containers for liquids (water bottles, laundry soap, etc.), aluminum, and tin cans. Though not for MRF applications, one truly innovative recycling system is the company’s plastic bottle de-labeler. This machine runs nonstop, performing the difficult task of tearing up bottle labels (including thermo-retractable sleeves) in a high-friction but nondestructive method. The goal of this machine is to minimize the PVC and PETG pollution caused by these labels. Amut’s system limits the amount of wear compared with other de-labelers, resulting in considerable savings and maintenance time with bolted (not welded) cutting elements. Their design allows blades to be used on four sides prior to sharpening. Amut has three sizes of de-labeler systems: Model DLB 10 (1,000 bottles per hour), Model DLB 30 (3,000 bottles per hour) and the Model DLB 60 (6,000 bottle per hour). The larger models are used to treat the whole bottle, while the smaller model handles rejected bottles from the main near infrared sorter.
Bulk Handling Systems (BHS) designs, manufactures and installs processing systems tailored to extract recyclables from the wastestream. BHS developed the first single-stream recycling system in the United States and has led the way with many firsts in MSW processing. Today, BHS builds some of the largest and most advanced single-stream and MSW MRFs in the industry, featuring BHS Tri-Disc, NRT In-Flight Sorting, and Nihot air separation technology. These facilities achieve industry-leading throughput, uptime, and recovery levels. BHS’s MSW recovery philosophy revolves around what it calls “closing-the-loop” on recycling, which is achieved when the MRF or fleet is powered by the waste it handles. This can be achieved through anaerobic digestion (AD), which is the focus of BHS partner company Zero Waste Energy. An excellent example of screen, air, optical, and AD technology coming together can be seen in Montgomery, AL, at the BHS-designed facility known as IREP at Montgomery. The Infinitus Energy-owned 30-tph system processes a “one-bin” material stream using BHS technology to recover organic material and up to 90% of available commodities. In this much-discussed collection model, residents place trash and recyclables in one bin, resulting in collection and participation advantages. Montgomery Mayor Todd Strange stated that, “The Infinitus Energy team has delivered a facility that far exceeds the expectations we had upon originally issuing an RFP to help us revive our recycling efforts. They have delivered the most sophisticated technology available in the world today to process our MSW and reduce our operating costs, savings that we estimate could be as high as $1.8 million annually. In addition, this facility will help us achieve recycling rates that will be amongst the highest nationally and put the city of Montgomery at the leading edge of managing solid waste.”
The CP Group of Companies comprises five brands and provides the waste and recycling industry a single-source solution for MRFs and recycling equipment. The CP Group of Companies has over 155 years of combined company experience and is unique among MRF suppliers in that it owns and operates its own MRF in San Diego, giving the company an operator’s perspective. This 20-tph facility serves as a test bed for new equipment and ideas, allowing CP to perform real-world research and development. It provides a wide range of MRF equipment (balers, conveyors, disc screens, trommels, optical sorters, compactors, air classifiers, etc.). As one of the first manufacturers of single-stream MRF systems, CP continues to innovate with such new products as its proprietary cam-disc-style CPScreen, which delivers excellent separation of 2D and 3D material, or the new Cirrus high-resolution sorting system for near infrared, color, and metal.
The Cirrus uses advanced digital signal processing and software algorithms to sort through a wide variety of mixed materials, including plastic bottles, other plastic, paper, cardboard, beverage cartons, e-waste scrap, metal scrap, municipal solid waste, refuse-derived fuel, commercial waste, industrial waste, and construction-and-demolition debris. It can operate at variable production rates, depending on the type of material it is handling, such as e-waste (.5 to 3.0 tph), paper (2 to 12 tph), and plastics (2 to 8 tons tph) at 98% energy efficiency. Color-sorting operations are performed by the L-VIS high-resolution color camera. Its setup (midair detection over a reflective or illuminated back reference) and mechanical configuration (slide or conveyor) can be tailored to the MRFs operating system. The company’s Aladdin optical sorter can separate plastics by resin type and color, being able to tell the difference between opaque and transparent objects. MetalSort is an optical sorting system for metals, using an induction-based true all-metal sensor that sorts ferrous, nonferrous, and stainless steel.
General Kinematics Corp. supplies recycling, foundry, mining, and process systems, and has adapted this equipment for recycling applications. The company is considered expert in the field of vibratory equipment for any MRF system and has modified its vibratory separation equipment to create such new recycling equipment as the Finger-Screen and De-Stoner Air Classifier-two pieces of equipment the company considers to be “the heart of your sorting system.” The results are efficient recycling systems that separate recyclables using low energy and low labor requirements. The Finger-Screen is a vibratory grizzly that utilizes a simple jamproof movement cycle. The unit creates a vibrating movement that spreads material across its operation deck, allowing for more efficient separation of materials. Staggered finger positions prevent material bypass without trapping, resulting in smooth continuous material flow through the remainder of the recycling process. The company’s De-Stoner Air Classifier comes in single-, double-, or triple-knife models. A dry classification system, it combines both vibratory action and high velocity/low pressure. The result is a fluidized and stratified wastestream that self-sorts according to difference in terminal velocity of particles. This allows for the easy removal of such heavy objects as glass, metal, and stone. General Kinematics’s latest R&D project (to be installed for the first time during the Summer of 2014) is the SXS screen This is a unique dual-stream screener, configured side by side, that can be used for various types of waste (MSW, C&D, industrial, etc.). These screens work together, side by side and in conjunction with a long-stroke design that creates twice the stroke with low horsepower.
Based in Omaha, NE, HDR is an architectural, engineering and consulting firm providing services to clients in all 50 states and 60 countries. A representative example of the company’s work is the Puentes Hill project. The Sanitation Districts of Los Angeles County (LACSD) was faced with the dilemma of landfills at or near full capacity. It simply lacked the available airspace to dispose of waste from more than 5 million customers and 78 cities in suburban Los Angeles. To buy time for the district to develop the long-term solution of hauling waste by rail, the LACSD built the $37 million Puente Hills Material Recovery Facility (PHMRF). This 4,400-tons-per-day facility, designed primarily by HDR, won the 2006 Solid Waste Association of North America Gold Excellence Award. At the facility, materials that can be usefully recycled are separated from the main wastestream, the remainder of which gets sent to a landfill. When all landfills in greater Los Angeles are closed, PHMRF will transition exclusively to waste-by-rail transport, sorting and shipping waste to the Mesquite Landfill, which is located in a desert area 200 miles outside of Los Angeles. The structure itself was designed and built with recycled materials (translucent panels, steel, carpet, and backing. To reduce energy needs, illumination is provided by 500 skylights. Water is reused and reclaimed. For aesthetic reasons, a modern 12,000-square-foot administrative building obscures the view of the production center with its cavernous 210,000-square-foot processing floor. Truck operations and vehicle traffic are designed to minimize noise, dust, odor, and environmental pollution. Misting systems, rapid-roll doors, and buildings clad in colors keep the facility consistent with the neighborhood, further minimizing visual impact. The current was intended to start at only 1,000 tpd, with provisions for future expansion s to 4,400 tpd. However, HDR’s cost benefit analysis (a perfect example of going above and beyond for a client) of its life cycle costs showed that it would be better to forgo the phased expansions and go directly to the planned maximum capacity. The result was overall budget savings and below-budget bids from building contractors.
A similar situation was faced by the city of Phoenix, AZ. The city was faced with the closing of its Skunk Creek Landfill, its last major waste disposal facility. HDR met the challenge with the 450-acre, $40 million North Gateway Campus, which includes the 4,000-ton-per-day North Transfer Station and Material Recovery Facility. In addition to the site’s administrative building, two scale houses, a maintenance facility, a fueling station, and top-loading ports that can accommodate future expansion plans, the facility is protected from the Arizona heat by a durable shell and a long roof protected with reflective and emissive roof paint for shading, as well as electrical and water systems designed for maximum efficiency. Ninety percent of the structure itself is built with recycled steel.
Mini MRF supplies what is essentially a “pre-engineered mixed waste processing system.” The company’s miniMRF is a “snap on” front-end modular recycling system the provides both high productivity and operational flexibility. Primarily designed as a standalone dirty MRF, the miniMRF can also be used by waste-to-energy facilities and biofuel plants that use organic waste as a feedstock, performing the important first step of removing noncombustible materials and materials of value from the wastestream. Each module is trailer mounted, allowing for rapid deployment and easy installation inside such existing facilities as new buildings, warehouses, waste-to-energy plants, or existing transfer stations. A module is usually rated at 35 tons per hour (150,000 tons per year) of unsorted MSW. Additional modules can be set up in parallel to increase overall production rates. The compact design allows for the efficient removal of such high-end recyclable materials as ferrous and nonferrous metals, organics, and glass. Additional specialized modules can be added in series for specialized material extraction. These include fiber modules utilizing near-infrared sorting to separate fiber and recover paper products (mixed paper, newspaper, office paper, flat cardboard, or corrugated cardboard); plastic modules that also use near-infrared sorting techniques to remove most commercial plastic resin by code; and the EcoEngineered fuel module that extracts combustible materials (paper, light film plastics, etc.) that can substitute for coal as a fuel source.
You can’t build anything (even MRFs) without a good, solid foundation. Modulo Beton provides such a foundation with its innovative, modular, precast concrete units specifically designed for the construction of split-level municipal solid waste recycling centers. The company’s unique patented design includes under-platform additional storage area. These modules are precast offsite and assembled onsite without the need for subsurface foundations. So, for a typical MSW MRF, these units can be installed in two to five days in a four-step process: site planning, system design, preparation of the base, assembling of the Modulo blocks, and finishing. Site design can be done by the user. With a load-bearing capacity of 13.5 tons to 63 tons, Modulo offers flexible design options that can be reconfigured or added to at any time. Safety and easy maintenance are built into the design of Modulo block facilities. Safety is provided by optional guard rails to allow for easy installation and removal of storage bins and by galvanized steel splash guards that protect personnel while making for easy maintenance and cleaning. Their concrete surfaces are easy to maintain, durable and resistant to corrosion. The sites are clean and aesthetically attractive.
One question often neglected during the MRF planning process is what to do with the recycled materials to prepare them for shipping, storage, and marketing. Sebright Products Inc., a manufacturer of industrial compactors, has the answer. A major supplier of self-contained precrusher and transfer station compactors, the company provides the equipment that a MRF would need to prepare extracted materials for shipping. Its 8-cubic-yard-capacity Model 9884T is operated by a 50-horsepower motor driving a pair of 6-inch cylinders capable of exerting over 101,000 pounds of force. The larger, with a capacity of 9 cubic yards, can also use 6-inch cylinders to generate over 121,00 pounds, or a single 7-inch cylinder applying over 165,000 pounds.
For over 40 years, Sierra International Machinery has been involved in scrap processing and the recycling business. Sierra provides a full range of processing equipment and technical support for MRFs and recyclers. Sierra’s extensive line of recycling equipment includes Sierra’s REB series two-ram balers, conveyors, high-capacity/high-density horizontal balers, shredders, and material handlers, etc. The company can provide complete system design or just a single component. For example, the Macpresse horizontal baler is designed with an exceptionally heavy frame to ensure long life in the dirty, dusty environments found in transfer stations and recycling operations. These balers are operated by a hydraulic manifold block that provides effective valve controls and eliminates hydraulic shock. Ease of operation and maintenance is enhanced by a structure that includes bolt-in replacement liners on all four sidewalls, as well as the compaction ram. The finished bales are secured with five to 10 wires, as required, depending on the product. A Siemens Simatic Industrial PC capable of providing management reports, production data, and operating costs, as well as self-diagnostic functions, is included. Today’s MRF’s demand equipment that can efficiently process multiple grades of materials desired by mills.
A new product that received high reviews during the recent ISRI and Waste Expo Shows was the Sierra E-9 Zero Emissions electric crane. This crane is ideal for inside applications with no diesel or propane fumes. It is totally electric/hydraulic, saving thousands of dollar a year in maintenance and fuel costs. Battery operated, it can work an entire shift without recharging. With a five-prong grapple, the E-9 can lift 2,700 pounds at maximum reach and 6,800 pounds at minimum reach. Its operating arm has a maximum extension of almost 20 feet and a lift height of 7 feet. This unit is tailor-made for RDF facilities.
Operating in the western United States for over 14 years, Titus Services provides turnkey design, fabrication, and installation services to MRF operators and glass-beneficiating operators. As a service provided, Titus is skilled and experienced in any number of MRF systems, doing everything from installing glass-cleaning and optical-sorting equipment, to the moving, designing, and installing of a single-stream MRF. MRF equipment installation includes conveyors, feed hoppers, bunkers, balers, trommels, compactors, baler liner replacements, and conveyor rebuilds. The company’s mobile staff of craftsmen are experienced in the installation of container line retrofits, balers, glass beneficiation equipment, plastic, fiber and glass sorting systems, balers, and sorting stations for single-stream MRFs. The company’s expertise covers a wide range of manufacturers and suppliers of MRF equipment (BHS, Bollegraaf, CP Manufacturing, TiTech, Pellenc, Machinex, Hustler, and Picvisa, to name a few).
Van Dyk Recycling Solutions offers systems for the recycling and sorting of single-stream, commercial waste, construction-and-demolition debris, plastics, e-waste, municipal solid waste, and specialized wastestreams. The company’s turnkey approach provides design, installation, and training along with lifetime service and support, all aimed at achieving client business goals. To date, Van Dyk has installed over 340 MRFs and 2,400 recycling and sorting systems-and 17 mega-MRFs with throughput capacities of 50 to 60 tph. The company’s single-stream systems include vertically integrated solutions using balers, screens, and sensor-based sorters. This technology comes together in Van Dyk’s complete multiMRF packages. Its multistream systems employ Bollegraaf sorting systems, TiTech sensor-based sorting, Walair density-separation systems, and 3D trommel screens. The multifunctional TiTech autosort 4 sorting system can handle a wide variety of materials. It is designed to maximize consistent in-feed rates and handle large objects by using oversized components. Advanced BollegraafPaper Magnet systems separate 2D paper from 3D boxes and cartons. High-efficiency Bollegraaf balers maintain throughput at the end of the operation.
A prime example of the Van Dyk design/build approach is the Grand Central Recycling and Transfer Station. According to Wilfred Poiesz, western vice president of Van Dyk Recycling Solutions, “This innovative plant can process and sort residential single-stream, dirty and dry commercial waste, and multifamily MSW, all over a single processing line. It is a scalable alternative for the recyclers who do not have the capital, volume, or needs for a multiple line mega-MRF.” The facility has an innovative design with traditional low-maintenance machinery and highly-automated controls capable of handling 600 to 700 tpd. “The fact that Van Dyk Recycling Solutions could think out of the box allowed them to formulate the most competitively priced proposal as well as the best use of space and people,” states Pete Perez, general manager of Grand Central Recycling.
Vecoplan LLC is a supplier of industrial shredders, screeners, and separators. For over 40 years, all of this equipment has found extensive use in the recycling industry, but the company’s leading product is the plastic shredder. Plastics make up a large fraction of any wastestream, and plastic reduction machinery is an essential first step to its recovery and extraction. Vecoplan designs, engineers, manufactures, supplies, installs, and trains personnel for plastic shredding systems. Its shredders can handle ABS, acetals, acrylics, engineered thermoplastics, mixed thermoplastics, HDPE, LDPE, nylon, PC, poloyolefins, PP, PS, and PVC. The company’s double-shaft shredders can process over 100 tons per hour. Their design includes two cutting rotors spaced apart from each other to cut against a fixed counter-knife. The fixed knife is positioned below in the bed of the cutting chamber and in between the two rotors. Shredded material passes through bar screens. The fraction that does not pass is pulled back into the cutting chamber for a second round of shredding. The company also excels at recovery systems that convert waste into clean energy. Utilizing anaerobic digestion and hydromechanical processing, Vecoplan’s energy recovery systems create fuel by fermentation of biological waste, household waste, and organic fractions of MSW.
Stadler America is a joint venture between Stadler Anlagenbau GmbH and Zimmer America Recycling Solutions (a division of ZARS-USA LLC). It provides a wide range of recycling equipment and systems including, single-stream waste sorting plants, ballistic separators, plastic sorters, and screening drums. The company has installed more than 200 complete turnkey recycling plants as well as more than 600 individual ballistic separators. Its systems can handle household waste, industrial waste, lightweight packaging materials, polymers, commingled material, MSW, plastic bottles, paper, OCC, refuse-derived fuel, and specialized wastestreams.
The company’s sorting plant for commingled materials is designed with a feeding hall and a processing hall. The feeding hall comes equipped with four feeding bunkers, a main feed-via-sack opener, and individual feeds (loose commingled materials, compressed bales, and loose plastics). The processing hall has a separating and dispensing unit that separates the wastestream into two separate lines. From there, the waste goes to ballistic separators, overhead magnets for removal of ferrous metal, eddy-current separators for nonferrous metals, manual sorting tables, plastic film extraction units, and near-infrared optical sorting systems. The bulk output from the system includes paper, plastic, and metals with secondary extraction of cardboard, plastic film, aluminum, newsprint, magazines, mixed paper, and several kinds of commercial plastic.
Used in Europe since 1980, the Stadler ballistic separator is a relatively new technology for the American market. With this machine, Stadler America is introducing a proven screening method to the US, having already built over 600 of these units worldwide. This machine consists of a set of six perforated paddles rotating offset against each other and angles that can be manually or hydraulically adjusted to match incoming wastestreams. It produces a three-fraction output: a 3D rolling fraction, a 2D flat fraction, and, very importantly, the fines fraction. Increasing the angle of inclination increases the amount of material that will fall into the rolling fraction, resulting in a cleaner flat fraction (and vice versa). The fines fraction is produced by material leaving the screens through the variable openings in the six paddles (standard openings are 2 inches by 2 inches). The result is the effective sorting of material flow into flat, screened, and rolling factions by size, shape, and weight (rolling and heavy materials like plastic bottles, cans, and metals; light flat materials like films, paper, and cardboard; and glass). Different models are designed for such different applications as the STT2000 for light packaging and mixed paper, the PPK for paper and cardboard, and the STT5000 for industrial waste, bulk waste, household waste, and construction-and-demolition debris.