Weathering the Storm

There has never been a better to time to make capital investments in your material recovery facility. There—I’ve said it. Yes, you heard me correctly. Now is the time to acquire as much equipment and plant improvements as you possibly can. How can I possibly justify that statement when prices for scrap metal in particular and recyclable materials in general have nosedived with the recent credit crunch and the market meltdown?

Why? Because equipment prices will never again be this low and financing will never be cheaper than they are today. Demand for scrap materials has not gone away; fearful economic times have depressed demand and economic activity. But as Warren Buffet wisely pointed out, it is just such fearful times as ours that present the best buying opportunities. Those factories in China and India that have been ravenously consuming everything from copper piping to cardboard are still there. They may currently be idle, but they are not going away. When (not if but when) the economy recovers, pent-up demand will soar and those material recovery facilities (MRFs) and recycling operations that are the most efficient and most highly automated will dominate the market during the upswing.

Not only will you be doing yourself a favor by making capital investments to the greatest extent possible, but you will also be hastening the inevitable recovery. This is due to the “paradox of thrift,” the economic concept that if everyone saves more money during times of recession, then aggregate demand will fall. When this happens, it effectively lowers the total savings in the population. The paradox argues that if everyone saves, then there is a decrease in consumption, which leads to a fall in aggregate demand and thus leads to a fall in economic growth. It is only natural to want to conserve cash and limit debt during uncertain times. However, there is no other proven method of escaping a major recession than economic stimulus—by government or by private industry.

The Process
Recycling systems at MRFs that emphasize automated sorting and processing equipment are referred to by the nickname of “dirty MRFs.” They are said to perform single-stream recycling since the waste arrives at the facility in a single, unsorted stream. In contrast, MRFs whose recycling systems rely heavily on manual sorting and processing of incoming materials are usually referred to as “clean MRFs.” Their type of recycling process is referred to as multistream recycling since major types of recyclable materials are source-separated for ease of manual handling into individual wastestreams prior to delivery to the facility.

It is the former type of process, single-stream recycling, which benefits from capital investment in sorting and processing equipment and automated control systems. Yet, even here, some manual sorting is usually required and performed as an initial step to separate paper and similar products from such bulkier items in the wastestream as metals, plastic, and glass. The automated portion of the recycling process utilizes the different physical and material characteristics to perform a separating step that removes a unique material from the wastestream. Further down the line, a different process separates out another type of material, and so on, until every different type of material is extracted and separated from the single wastestream flow.

Typically, the first material to be removed is scrap metal. There are two types of scrap metal: ferrous and nonferrous. To remove ferrous metals, the entire wastestream is carried by a belt through a magnetic separator that pulls out the ferrous metals. Although overhead magnets are often used, a more convenient configuration puts the magnets under the belt. As the belt carrying the entire wastestream passes over the magnets, the ferrous metal clings to the belts while the rest of the waste falls off at a drop off point somewhat farther down the line. As the belt continues back under its rollers, the ferrous metal sticks to the belt until it is pried off by a scraper blade and falls into a collection bin.

Nonferrous metals (mostly aluminum foil and cans) are removed afterward by a similar process called an eddy-current separator. An eddy-current separator utilizes a spinning magnet with alternating polarity to induce an electrical current in the nonferrous metal. The resultant electrical current creates its own magnetic field around the piece of otherwise nonmagnetic scrap metal, which creates a repulsive force against the rotating magnetic field. The induced magnetic field is repelled by the magnetic field utilized by the eddy-current separator, and the nonferrous metal literally leaps off of the processing table or belt into an adjacent collection bin.

Nonferrous metal can be further separated by an air knife, a device that can separate light aluminum foil from heavier metal cans. The “knife” refers to sheet flows of high-velocity air blasts arranged in a parallel sequence. The force of the air blasts lifts the aluminum foil from the heavier cans. Swirling and remixing are prevented by the separation distance between the sheets of airflow. Each type of recovered metal can be compressed in a metal baler for convenient shipping and resale.

The remaining wastestream (primarily cardboard, but also including plastic, glass, paper, or wood) continues on to disc screeners that sort by both shape and size. Waste enters the screeners’ inflow bin by means of a variable-speed conveyor belt that regulates the rate of movement. By altering the speed of the belt, the operator can even out the flows of incoming waste and prevent clumping, clogging, or exceeding the machine’s operating capacity. Disc screens consist of a floor covered with rotating discs of different sizes and shapes (circular, oval, or star,) depending on the type of material being processed. The opening sizes can be adjusted to manage different types of materials. The resultant wave motion carries larger and lighter objects higher, while heavier small objects (such as glass shards) move to the lower portion of the separator and drop through holes in the screen floor.

During these various operational stages, it is inevitable that a significant fraction of the glass portion of the wastestream gets broken into shards. These shards, as well as other objects, pass through a rotating trommel. Trommels are rotating drums equipment with small holes (usually about 2 inches in diameter) in the side and directional vanes that promote gravity separation on their interior walls. Usually, the trommel’s axis of rotation is at some angle to the horizontal to facilitate the discharge of material (a horizontal axis would result in too slow of a flow through, while vertical would be too fast). In addition to sorting vanes, more complicated trommel designs utilize flights that carry the material back up to the high end of the trommel for another pass through. This process sorts large pieces of glass and cullet suitable for recycling from small pieces that become residue.

Glass pieces large enough to be recycled can be further separated by a color sorter. This optical sorting mechanism divides glass pieces by their various colors (brown, amber, green, clear, and mixed.) Glass sorters rely on light spectrophotometry that can distinguish between various colors of glass by measuring the wavelengths of the visible light reflected back at the optical sensors. Ceramic material, on the other hand, is completely removed from the glass waste, after which the glass can be sorted by color. Once finally separated, the individual colored glass shards get sent through a glass pulverizer that reduces their size and consolidates their volume for shipping and resale.

Plastic waste objects (mostly bottles and other types of containers) also go through a subsequent sorting process. Containers and cartons are separated from bottles and flattened by a plastic baler. The bottles are further separated by the various types of plastics (HDPE, PVC, PET, etc.). The various types of plastic are ground down into particles by a granulator, and then compacted by a baler prior to shipping and resale.

Meanwhile, the paper waste that was initially separated from the wastestream undergoes its own recycling process. It also can be passed through a rotating trommel to separate mixed paper products from unusable residue. The residue falls out of the small holes on the sides of the trommel’s drum while the reusable paper passes through and continues with the sorting process. After this point, manual sorting is usually required to separate out the various types of paper (glossy magazines, newsprint, office paper, etc.). Each kind of paper is fed into its own baler for compaction and binding prior to transport to resellers.

A type of separator often used to separate mixed paper streams (as well as other lightweight materials) is the air classifier. This can be used at the start of the process to separate out paper waste from the general wastestream and avoid manual separation. Lighter materials are separated from heavier materials by means of a high-velocity airstream induced in a stack structure by a powerful blower installed at the top that sucks air up the shaft. Waste is fed into the stack at about the mid point. Below the waste feed is an air inlet controlled by a rotating airlock. Heavy objects fall to the bottom of the stack for removal and further sorting or disposal as unusable residue. Lighter materials are sucked up to the top of the stack. Often the air-separator stack is equipped with a cyclone separator that causes the light materials to lose their velocity and settle out based on their relative density and size.

Prior to transport for resale, almost all types of recycled materials are compacted to smaller volumes and higher densities by means of compactors designed to handle each type of material. Often, the compacted mass is further bound up with string or wire to ensure structural integrity during transport. Low-density materials (cardboard, aluminum cans, newsprint) especially need compaction to reduce what would otherwise be extremely high per-ton transport costs. Compactors are electronically controlled hydraulic systems sized for a particular task and anticipated flow through quantities (tons of materials per hour).

In many ways, shredders, which are the operational opposite of compactors, are also useful, especially at the start of the process. Not everything that comes into a MRF is easily sorted cans and cardboard. Large objects and bulk items such as appliances and tires must be recycled as well, and these have to be shredded to segregate the individual materials used in their manufacture. Once the metal and nonmetal fragments have been produced, they can be added to the general wastestream and processed in the same manner as curbside waste.

Major Suppliers
Continental Biomass Industries is a manufacturer and supplier of chippers, grinders, and shredders. Its Grizzly mill is a fixed grinder that is primarily designed as a wood hog. However, it can be reconfigured specifically as a primary, secondary, or tertiary grinder for demolition debris, MSW, yardwaste, or wood debris. The Model 8400 is a mobile (track- or wheel-mounted) unit that can operate with four different rotors, allowing it to grind a wide variety of materials, including contaminated construction debris, railroad ties, and MSW. CBI Shredders can be either portable or stationary with either electric or diesel drives. They can handle for high-volume primary processing of metal-contaminated C&D (rebar stuck in concrete chunks), bulky waste, or MSW. The Annihilator can process more than 100 tons per hour of MSW. Its heart is a 6-inch forged steel, 20,000-pound rotor with reversible tips. It is capable of being operated in auto reverse, and has as automatic purge cycle for easy cleaning. The CBI prescreener is usually used as a prefeeder in conjunction with a Grizzly grinder. It separates out abrasive fines, reducing wear and tear on the Grizzly and increasing its productivity.

Doppstadt US supplies volume-reduction equipment for the recycling industry including low speed shredders, trommel screeners and high-speed grinders. Their DW series slow speed shredders emphasize efficiency. The DW can handle different applications and loads with very low fuel consumption. It can quickly process MSW or more slowly process contaminated construction and demolition debris as well as bulky land clearing waste. The company’s SM series trommels provide operational versatility and screen sizing changes needed for multiple applications including topsoil, multiple C&D streams and MSW. Doppstadt’s AK series grinders utilize precision to control the consistency of the materials being fed into the hammer mill. These materials include wood and wood products such as dimensional lumber, greenwaste, and land-clearing debris.

Weima America produces an extensive range of size reduction equipment that includes single-shaft shredders, four-shaft shredders, horizontal shredders, granulators, two-stage recycling systems, and briquetting presses. The company’s WL(K) series shredders are low-speed, low-rpm machines designed for the recycling industry, capable of shredding all types of wood, paper, plastics, and more. They utilize V-Rotor technology with mounted cutting knives capable of handling abrasive materials and allowing for easy removal and replacement. The system is adjustable, allowing for variable knife projections and optimized cutting geometry producing consistent particle sizes.

Newly introduced by Weima is the “E-Rotor” WLK shredder. The purpose of the new rotor is specifically for the recycling of film and fibrous materials. This includes the historically tough-to-shred woven and nonwoven fibers. The design has also eliminated wrapping issues with thin gauge films and fibers that sometimes occurs with other rotor designs. One of the many benefits to the new E-Rotor design is that it generates a relatively high bulk density when processing film. This helps to maximize the efficiency of the repelletizing process.

The ZM series is the company’s four-shaft shredders, often used in such applications as cardboard boxes, electronic hard-drive media, medical waste, veneer, and bulky plastic materials. These shredders are typically used to handle waste as it is generated in a manufacturing process rather than in a separate shredding/granulating room.

The company’s horizontal line of shredders range from the Beaver, designed for low-volume applications and sized to fit in confined spaces, to systems like the Jaguar and Tiger, which allow for greater-volume operations. Horizontal shredders are ideal for wood strips being produced from ripsaw lines or for plastic deck boards or profiles. Weima’s largest horizontal machine, called the Leopard, has a patented tank-track infeed roll design that gives the shredder the ability to grab stacks of materials from strips to bulky block waste all at once, allowing for more versatility and greater output.

Weima’s line of briquetting equipment has become increasing popular in the wood and paper industries. This equipment takes wood chips, sawdust, shavings, or even paper dust and compresses it to what looks like an oversized hockey puck. The major benefit of this equipment is that it reduces the amount of loose material and waste bins and allows for easy transport and removal. The additional benefit is that it has a great Btu value, allowing the customer to burn the material in existing boilers. It is also a great alternative when security is an issue and complete destruction is needed.

Other equipment, such as the NZ granulator, is capable of regrinding small- to medium-size particles in a two-step process. This is typically put in place after the WLK preshredder for materials that need to be reduced to less than three-eighths of an inch in particle size.

Weima also manufactures equipment for the MSW and refuse-derived fuel (RDF) industries. Its Energy Line consists of four different models. The Weima PreCut is a single-shaft preshredder for unsorted highly contaminated material streams and is ideally utilized as the first step of multistage waste processing. The Weima PowerLine is a high-capacity secondary shredder in a multistage operation or a single-stage shredding solution for clean material streams from post-industrial waste. Equipped with the technology of the PowerLine, the new EcoLine is designed for small to medium throughput requirements, regardless of whether it is used in a single-stage operation or as a secondary shredder. Featuring a high-speed rotor, the FineCut is designed as a secondary grinder in a multistage recycling/RDF plant.

Bulk Handling Systems LLC provides turnkey solutions for material recovery facilities. The company has established a new, patented MSW process that has achieved a recycling rate of over 75%, keeping this waste out of landfills and capturing 90%–99% of high-value commodities like PET plastics with a single operational cycle. Beginning with the BHS Bag Breaker (an important and often neglected first step) which eliminates the need for manual bag opening, waste is carried to the various processing stations in the BHS recycling system by means of heavy-duty chain belt, idler belt, sort belt, and slider bed conveyors. The BHS Debris Roll Screen sorter can process MSW, C&D, greenwaste, compost, plastic, glass, and tires. Its patented design provides efficient material agitation and separation with operation versatility provided by variable speed and disc drive with fine-tuning provided by angle adjustments. Following the bulk sorting, the wastestream passes through BHS’s patented combination of technologies, including BHS Polishing Screens, air systems, and optical units. The Polishing Screens utilize BHS’s no-wrap disc design and remove fibers and containers for separate processing.

CP Manufacturing, a division of the IMS Group of companies, provides turnkey solutions for the separation of recyclable materials. CP designs and builds entire systems meeting its clients’ requirements. These systems process curbside, picked-up, commingled containers (glass, plastics, aluminum, and steel) and fiber (OCC, ONP, mixed paper, and containers) in a single automated system. The key to efficient sorting is the patented disc screen technology. CP’s disc screens are engineered to optimize separation while minimizing downtime and maintenance costs. Though unique to each need and specialized in design, CP’s MSW processing systems follow an optimized work flow: presorting, fine-screening and residue removal, magnetic and eddy-current separator, container and paper screens, container processing, and fiber processing. In addition to the company’s MSW processing systems, CP also offers solutions for single-stream, C&D, and waste-to-energy processors with its heavy-duty, automated separation equipment, having custom-designed, fabricated, and installed over 300 MRFs worldwide to maximize the customer’s processing time while lowering costs.

Allegheny Shredders is a premier manufacturer of high-capacity shredding systems with capacities from 1 to 25 tons of paper per hour. In addition to Allegheny’s complete line of high-capacity shredders, the company also manufactures cross-shredding systems, security grinders, product and e-scrap shredders, conveyors, tippers, horizontal balers, dust collection, and auto-feed systems. So whether you need to destroy documents, wastepaper, plastics, products, or e-scrap, Allegheny has a practical solution to meet your needs—and your budget. To complement Allegheny’s line of equipment, the company also provides expert consulting for collecting to processing to recycling for a profit.

B.E. Equipment sells and services new and used recycling, waste-reduction, and solid waste handling equipment. The company offers a wide variety of new, reconditioned, and used recycling equipment, including balers, conveyors, sorting systems, shredders, commercial/industrial compactors, core strippers, and briquetters. Flexible finance options allow customers to purchase or lease the equipment. The company also provides transport, installation, maintenance, and training services. Its used equipment, often obtained from liquidation operations, includes reconditioned and renovated equipment with upgraded or restored operational performance. Its inventory includes equipment from all the major industry manufacturers and suppliers, along with an extensive supply of spare parts.

Machinex Industries offers complete, custom-engineered sorting and recycling systems for specific applications. This includes a line of specialized conveyors and the company’s Mach Series material separators. Machinex offers a complete package of single-stream Mach separators. It achieves a high level of sorting purity and efficiency made possible by its highly adaptable deck systems. Sorting configuration flexibility gives the possibility to adjust to any material stream. Variation of deck-angle speed and screening configuration are key elements to system flexibility. The Mach sorters are also fully adaptable, allowing for full integration into existing setups. Design modifications can be quickly made to meet specific needs. But Machinex has an added ability to integrate multiple processing applications into whole systems that can be developed as turnkey operations for MSW waste processing. The company’s front-end processing equipment maximizes recycling recovery rates through optimizing the various components combined with detailed MRF design-consulting services. Its peripheral equipment includes conveyors, bag openers, trommels, disc screens, magnetic and eddy-current separators, and electric controls.

Sennebogen of North America offers a green line of bulk material handling equipment. The company’s Model 305c Multi-Hander can be described as a cross between a front-end loader and a cherry picker, which makes it extremely useful for managing recycled materials. In this unique design, both the bucket and the operator’s cab can be raised by lifting arms. The ability to elevate the cab during operations provides superior visibility for the operator. Its articulated bucket is specially designed to allow it to compact in-place materials that it has loaded into dumpsters. With a 124-horsepower power plant, it is capable of lifting up to 11,000 pounds in a single load. Operational versatility is provided by multiple types of buckets and attachments for different jobs (light material bucket, bucket with hydraulic clamp, bucket with teeth, fork lift, lumber forks, snow plow, orange-peel grab, and log grapple). A wide wheel base and tight turning radius provided by its independently turning wheels combines stability with maneuverability. Larger versions include the Models 821M and 821R. Both are powered by a 142-horsepower engine and can lift 54,000 pounds and 51,600 pounds respectively. Designed for managing larger objects, these machines come equipped with grapples or magnet attachments. Their large boom lengths and stabilizing footpads make them suitable for large-scale outdoor use.

SSI Shredding Systems produces a line of shredders for multiple applications capable of efficient product destruction and volume reduction. The company provides four model types: Uni-Shear, Dual-Shear, Quad, and PRI-MAX. The Uni-Shear (a one shaft shredder) can process materials such as plastic, paper, and nonferrous metals into chips measuring three-quarters of an inch to 3 inches in size at a processing rate of 0.5 to 5.0 tons per hour. It is also useful for the secure destruction of documents and computer files. Its single-rotor design incorporates a ram-assisted vertical feed. This PC-controlled “smart ram” improves processing operations, minimizing downtime due to clogging. Depending on the materials being processes%