Now it's easier than ever to find the right portable equipment to handle onsite debris.

By Daniel P. Duffy

Tub-Grinder Basics
Wood-Chipper Characteristics
Tub-Grinder Models and Capacities
Screener Basics
Screener Models and Performance

Clearing and grubbing is only the first step in site preparation. Once the trees have been knocked down, stumps removed, and brush cleared away, the resultant debris must be managed in the most cost-effective manner possible. Given the large volume and relatively small density of this debris, simply hauling it off can be very expensive. If you process this greenwaste on-site by tub grinders, wood chippers, and portable screening units, however, a much denser and cheaper-to-haul product can be produced. The resultant mulch can also be reutilized on-site in an environmentally friendly manner that avoids all hauling and disposal costs. This article will familiarize you with the basics of operating and evaluating these processing units while providing information on some of the more common models.

Tub-Grinder Basics

Tub grinders are the primary means for processing large quantities of woodwaste and construction debris in the field. Nine characteristics define and categorize tub grinders and chippers:

Power. Measured in horsepower, power defines how much debris can be processed by the tub grinder as well as the maximum size of the debris objects the machine can safely handle. Power should not be measured only in terms of overall power. Perhaps more important is the amount of horsepower delivered to each of the grinder's knives or hammers.

Production. Measured in tons or cubic yards per hour, this characteristic describes maximum feed rates into the tub grinder. Production rates vary with the type of material being fed. A typical tub grinder can process approximately twice as much yard and brush waste than stumps and logs and three times as many pallets and construction waste.

Transport. A description of the basic mobility of the unit out to the site. Nearly all industrial tub grinders are transportable to some degree. Naturally, larger units are more difficult to transport, especially in rough terrain or along roadways with steep grades. This should not preclude large-scale tub grinders from consideration even on difficult sites. It might make economic sense, given the much higher production rates and efficiencies of the larger tub grinders, to site the unit as close to the work area as practical and utilize haul trucks to transport the debris to this central location for processing.

Weight. Measured in tons, weight provides an overall machine classification as it directly relates to power and production. Tub grinders range from small units (15-20 tons) to very heavy units (50-60 tons). Smaller machines tend to be specialized wood chipping units because of limits on power plant. Larger units tend to be fixed facilities because of difficulty in transport.

Feed Opening. Measured in feet or inches squared, this determines the largest object that can be fed into the tub grinder for processing. Large-scale wood processing will require minimum feed openings in the 3- to 5-ft. range. For smaller jobs, openings in the 2- to 3-ft. range are acceptable.

Discharge. A description of the mechanism for ejecting and collecting processed materials, dual auger feeds to a conveyor belt are fairly typical. Conveyor belts vary in width from 2 to 5 ft.

Tub Diameter. Measured in feet, the tub diameter determines how much material can be processed simultaneously and also the number of hammers available for grinding since the size of the tub relates to the diameter of the hammer mill. For example, a tub with a diameter of 8.5 ft. would feed a hammer mill of 4-ft. diameter operating 20 hammers, whereas a tub with a diameter of 14 ft. would feed a hammer mill of 5-ft. diameter operating 26 hammers.

Drive Train and Protection. This provides a description of the drive train used to operate the hammer mill, feeding unit, and conveyor belt as well as the limiters, breakaway, and coolant systems designed to protect the drive train. Direct drive is standard for tub grinder units with full breakaway and torque limiter protection.

Extras. In addition to the basic features, tub grinders come with many useful options. These vary from the relatively simples items (such as vandalism lock packages, toolboxes, custom paint jobs, and air compressors) to more advanced features (such radial stacking conveyors, fuel transfer pumps, and auxiliary hydraulic power units).

Wood-Chipper Characteristics

Now it's easier than ever to find the right portable equipment to handle onsite debris.

Wood chippers are in a different category than tub grinders. Smaller and more portable, they are used to render brush, branches, and small trees into useable mulch. They are not as powerful as tub grinders, nor are they able to process as wide a variety of materials. Yet wood chippers can be used exclusively in small jobs or as auxiliary units to the larger tub grinders. Higher overall productivity rates can be achieved with a tub grinder managing large trees, stumps, and logs with a wood chipper processing smaller objects.

Chippers use "knives" instead of "hammers" to grind incoming wood debris. These are attached to rotors machined from a one-piece, heat-treated alloy steel billet. Knife seats in the better models are ground to finish dimensions with a 1/1000-in. tolerance.

V-belt drives are preferred, as they provide optimum rotor speed selection and eliminate the risk of damage from misalignment or sudden stoppage. Bearing housings should also be protected against the entrance of dust by an annular space, located between the bearing housing and antiwear plate. Recirculating lubrication systems with oil coolers help ensure maximum bearing life. Some engines are water- or air-cooled.

Knives should be manufactured to the highest-quality standards from heat-treated proprietary alloy steel. Rotor knife blades are held within tolerance limits of 0.002-in. total radial runout per set. Stationary knives, with gap-adjusting screws, are accessible from outside the cutting chamber and are securely held in the set position under hardened alloy-steel clamp bars.

In addition to the knives, discharge ports are also subject to wear and tear from normal operations. Granulator discharge grates, subject to heavy impact and abrasion, should be made from wear-resistant, heat-treated alloy (similar to the knives) plate with drilled holes. All grates need to be replaceable and interchangeable with hole sizes varied, depending on the type of material processed.

Ease of maintenance is a primary concern as these units face rough usage and continuous wear and tear. Hydraulically opened side doors ensure quick and easy access to the cutting chamber for routine knife inspection and maintenance. Hydraulic cylinders swing open the upper part of the cutting chamber for complete access to rotor and bed knives. Access to the cutting chamber comes by means of a manually operated, built-in hydraulic jack that raises the upper part of the cutting chamber, swiveling it to swing clear for fast access.

Because the knives are subject to extremes of heat stress, they require cooling. One effective configuration involves dissipating heat by cooling water recirculating through the hollow doors of the cutting chamber and internal passages in the sidewalls under the knife seats.

Feed and discharge hoppers should be appropriately sized for the jobs. Optional crossflow aspirators, integral to the granulator discharge hopper, improve cleanliness in systems chopping high-fiber material.

Tub-Grinder Models and Capacities

The following are specifications for commercially available tub grinders (from product literature provided by the manufacturer or supplier).

Morbark Model 1500. Designed for extremely large-volume woodwaste grinding, it's recommended for the largest municipal and private solid waste facilities, landfills, contractors, and wood yards. It can process virtually any size and shape of woodwaste material, including stumps, logs, brush, ties, pallets, bark, greenwaste, and construction and demolition (C&D) debris at rates of 180-500 yd.³/hr., depending on the material being processed. Effective as a primary or secondary grinder, it is the only 15-ft.-diameter tub grinder on the market. Completely portable, it can be set up in five minutes. A complete breakaway torque limiter provides drive protection, which eliminates the need for belt drives, belts, sheaves, and jackshafts. Standard features include full hydraulic tub tilt, a hydraulic folding conveyor, dual auger discharge, a pressure-compensated hydraulic system, and a hydraulic rod puller. It is powered by a 1,000- to 1,050-hp Cat or Cummins engine and weighs in at 40.5 tons. The feed opening measures 39 x 62 in.

Morbark Model 1200XL. The target for this unit is large, industrial-volume woodwaste disposal, reduction, and recycling. Its use is applicable for municipalities, counties, solid waste facilities, land clearing, recycling and demolition contractors, landfills, composting facilities, and wood yards. It can process stumps, brush, pallets, C&D debris, railroad ties, bark, and greenwaste up to 48 in. in diameter at rates of up to 300 yd.³/hr., depending on the material. It can be used as either a primary or a secondary grinder. The unit is completely portable and self-contained. It comes equipped with a knuckleboom loader, which reduces the need for support equipment. The complete breakaway torque limiter eliminates the need for belt drives, sheaves, and jackshafts. Dual auger discharge with pressure sensor is superior to belt under the hammer mill. The unit includes full hydraulic tub tilt, a hydraulic folding conveyor, and a pressure-compensated hydraulic system. It is powered by a 650- to 750-hp Cat or Cummins engine and weighs 31 tons. The feed opening measures 30 x 52 in.

Bandit Chipper Model 65. This compact, 6-in.-capacity chipper works well within the rental industry, with lawncare and landscape contractors, and as a first-time chipper with some commercial tree services. The Model 65 is also useful to homeowners who want a commercial-grade chipper to convert unwanted tree waste into dimensional chips for mulch, compost, and pathways. It also performs well at campgrounds, parks, and recreation departments. This model has a 12-in.-wide chipper opening, which is double that of most other 6-in.-capacity chippers on the market. The wider opening allows limbed and forked material to pass through the chipper with little hang-up; therefore, limiting the amount of trimming. A variety of gas and diesel engine options from 20 to 35 hp are available. The Model 65 weighs approximately 2,000 lb. - easily towed by car or pickup.

Bandit Chipper Models 150XP, 200XP, and 250XP. Three models of 12-in.-diameter-capacity Bandit chippers are available. The Model 150XP is a basic, economical 12-in. chipper. The Model 200XP has a faster feed rate and a few features that are optional on the 150XP. The Model 250XP has a much wider chipper opening and a bigger infeed chute. These models emphasize rugged construction, powerful feed systems, and large infeed openings that are key to chipping trees and brush with limited trimming. Bandit also offers a wide range of gas and diesel engine options from 56 to 130 hp.

Bandit Chipper Model 280XP. This model has an 18-in. chipping capacity, making it a highly productive hand-fed chipper. The unit has a large 18- x 20-in. chipper opening that, along with the powerful feed system, allows the 280XP to chip limbed, forked trees and multiple stems. It is useful for both big tree takedowns and light land clearing. This machine is a hydraulic-feed, disc-style chipper with the 45° angled feed. Engine options include Cummins, John Deere, Perkins, and Ford from 100 to 200 hp.

Bandit PTO Chippers. Bandit's Models 65, 90XP, 95, 150XP, 200+XP, and 250XP are offered with a PTO drive. The PTO chippers come trailerized with up to three axles or with a three-point hitch. A self-contained hydraulic system incorporated into the drive provides the power to the feed system on all of the Bandit PTO chippers. There is no need to tap into the hydraulic system of the tractor. The PTO Model 65 and 95 chippers, with their straight-on rear feed, are very popular for those who want to use a PTO chipper in an orchard. The 90XP, 150XP, 200XP, and 250XP PTO chippers feed at approximately 45° to the tractor.

Bandit Models 1290 and 1690. The conventional drum chippers, which utilize a solid cylinder with rotating knives without a hydraulic feed system, have been a mainstay of the utility-line maintenance contractor for more than 30 years. These simple, efficient brush chippers are easy to maintain. They come with a fixed-end discharge, and a side chute with a defer is available to discharge material at a right angle through the rear discharge. Bandit offers two models: the 1290, which features a 12-in.-wide roller, and the 1690, which features a 16-in.-wide roller. The drum chippers have gas and diesel engine options from 65 to 120 hp.

Bandit Chippers Model 1850. This 18-in.-diameter-capacity whole-tree chipper, with a 250-hp diesel engine, works well for land-clearing contractors and logging operations that wish to utilize logging slash waste. The Model 1850 comes with or without a loader. Without a loader, the chipper commonly works in conjunction with a knuckleboom loader on the logging site. The unit performs well in mechanized logging operations where logs and pulpwood are extracted. The chipper can chip tops, limbs, and unmerchantable material to provide total utilization.

Bandit Chippers Model 3680. A machine for reducing piled brush, stumps, pallets, construction waste, housing demolition, greenwaste (including palm waste), newspapers (wet or dry), railroad ties, and logging slash sawmills waste. The machine's cutter-mill design, shaped like saw bits, limits power requirements and energy consumption. While minimizing damage for such foreign materials as rock and steel, the Model 3680 produces compost material, animal bedding, or uniformly sized material for wood-fired boilers. The 4-ft.-high, 5-ft.-wide infeed conveyor is easy to feed. An auto-feed speed governor automatically controls the feed of materials into the machine. Radio remotes control the functions of the machine from the cab of the loader filling the machine. The machine is road legal without permits and comes with a 30-ft. conveyor that discharges to a height of 17 ft., 6 in. This unit comes with Deere, Cummins, or Cat diesel engine options in horsepower ranges of 350-500. The Model 3680 commonly works at landfills to convert waste into recyclable products or reduce the size of the material going to the landfill. The unit is also converts logging and sawmill waste into useful products. It will process up to 75 tph, depending on the material.

Diamond Z Model 1136B. This model applies up to 30 hp to each of 14 40-lb. hammers operating in a 36-in.-diameter hammer mill. It weighs 19 tons with a tub diameter of 11 ft. A 300- to 425-hp Cat engine powers its direct drive. Production rates vary with type of material. Stumps and logs can be processed at 30 tph, yard and brush waste at 40 tph; and pallets and construction waste up to 45 tph. The primary application for this model is small-scale wood and construction debris grinding operations.

Diamond Z Model 1248B. This model represents the midrange, portable tub grinders. Useful in a wide variety of woodwaste operations, it can process stumps, logs, construction materials, greenwaste, and pallets. Its direct-drive 550- to 650-hp Cat engine operates 20 hammers in a 48-in.-diameter hammer mill. It weighs 24 tons and has a tub diameter of 12 ft. Stumps and logs can be processed at a rate of 45 tph, yard and brush waste at 55 tph, and pallets and construction waste at 60 tph.

Diamond Z Model 1463B. This high-end tub grinder has the capacity to process a wide range of waste products. At 1,340 hp, its direct-drive Cat engine delivers power to 26 heavy (120 lb. each) hammers operating in a 63-in.-diameter hammer mill. It weighs 49 tons and has a tub diameter of 14 ft. The types of materials it processes include stumps and logs (100 tph), yard and brush waste (85 tph), pallets and construction waste (120 tph), railroad ties (90 tph), solid waste (60 tph), and tires (1,500 each per hour).

Totally Enclosed Tub Grinders. Diamond Z and other manufacturers make totally enclosed tub grinders, which serve to eliminate airborne debris, minimize dust, and suppress noise. These grinders feed material in through entrances in the sides of the tubs covered with enclosing lids. These basic modifications to other tub grinder models greatly increase safety. These models work well at locations close to pedestrians and traffic.

Vermeer TG525. Designed for heavy-duty operations, the TG 525 employs an extra-large cooling system, automotive-style fuses, and a sealed electrical box to meet challenging work conditions. Tub-support rollers reduce friction and lower hydraulic operating pressure. It weighs 60,500 lb. with a triple-axle and loader and is 45.6 ft. long, 12 ft. wide, and 13.5 ft. high.

Vermeer TG400A. The TG400A features a 3,000-lb. rotor and hammer assembly. The grinder weighs 57,400 lb. with a tandem axle and loader and is 45.6 ft. long, 12 ft. wide, and 13.5 ft. high.

Fecon Hogzilla MZA 3250. Designed for heavy-duty operations, the MZA 3250 is trailer-mounted with tandem axles, a 325-hp Caterpillar engine, a rotor speed of 1,100 rpm, a hammer-mill width of 58 in., a loading height of 6 ft., a length of 25 ft., a width of 8 ft., a height of 10.6 ft., and a weight of 23,000 lb.

Fecon Hogzilla MZA 2500. Trailer-mounted with tandem axles, the MZA 2500 can be towed at 50 mph. It has a 250 Caterpillar engine, a rotor speed of 1,100-rpm, a hammer-mill width of 58 in., a length of 25 ft., a width of 8 ft., a height of 10.6 ft., and a weight of 20,000 lb.

Peterson Pacific HC 7400 Portable Heavy-Duty Recycler. The HC 7400 is the company's largest horizontal recycler with an 800-hp engine and an approximately 88,000-lb. weight. It's 43 ft. long; 10 ft. wide; and 13 ft., 6 in. high. The production volume is 540 yd.³/hr.

Peterson Pacific HC 5400 Portable Heavy-Duty Recycler. The HC 5400 is powered by a 575- or 800-hp engine. It's 41 ft. long, 10 ft. wide, and 13 ft. high. The production volume is 325 yd.³/hr. (570 hp) or 500 yd.³/hr. (800 hp).

Peterson Pacific HC 2410 Track-Mounted Heavy-Duty Recycler. The HC 2410 horizontal recycler features a 460-hp engine and weighs approximately 61,000 lb. It is 36 ft. long; 9 ft., 10 in. wide; and 11 ft. high. The production volume reaches up to 250 yd.³/hr.

Peterson Pacific HC 2400-A Portable Heavy-Duty Recycler. The HC 2400-A features a 350- or 460-hp engine and weighs up to 45,500 lb. It's 43 ft. long; 8 ft., 6 in. wide; and 13 ft., 4 in. high. Its production volume reaches up to 262 ft.³/hr.

Duratech Industries HD-8. The HD-8 industrial tub grinder can be towed by a ć-ton pickup. With an 8-ft. tub, it offers a heavy-duty, 26-in.-long grinding hammer mill. Its grinding cylinder is constructed of 0.75-in. hammers with 0.5-in. cylinder plates. Weighing 10,600 lb., the unit is powered by a 4BTA 3.9 Cummins 130-hp diesel engine.

Duratech Industries HD-9. The model HD-9's 9-ft. tub tilts hydraulically to 90° for easy, unobstructed access to the hammer mill. The unit is available with a 275-hp electronically governed John Deere engine, which is protected by both a friction clutch and a torque limiter.

Duratech Industries HD-10. The HD10 Tornado features a 10-ft. tub with optional grapple loader. Weighing 32,300 lb. with the Hood 7000 Series grapple loader, the diesel-powered Tornado has a 22-ft. hydraulic discharge conveyor to stack material to a height of 18 ft.

Duratech Industries Tromax 6012. The Tromax 6012 is a partner to many HD-series tub grinders.

Duratech Industries Grindmaster 410. The Grindmaster 410 weighs 39,950 lb. with a 20-in.-long x 48-in.-wide x 38-in.-deep hopper. The rotor drum is 48 x 38 in. and powered by a 300-hp Caterpillar Model 3306.

Duratech Industries Grindmaster 512. The Grindmaster 512 weighs 52,000 lb. with a 181-in.-long x 60-in.-wide x 38-in.-deep hopper. The rotor drum is 60 x 38 in. and powered by a 425-hp Caterpillar Model 3406.

Precision Husky ProGrind H-3854. ProGrind H-3854's large-diameter infeed roller is sensitive enough to permit grass clippings, brush, limbs, pallets, slabs, logs, and stumps to be fed at variable speeds for continuous, rather than batch, feeding. It is powered by a 500-hp Caterpillar 3406 DITA engine or a 750-hp Caterpillar 3412 engine.

Precision Husky ProGrind 900. Powered by a Cummins 100-hp turbocharged diesel engine with an 11-in. Wichita clutch, the 10,200-lb. ProGrind 900's specifications include a transport length of 18 ft., 6 in.; a height of 7 ft., 7 in.; and a width of 7 ft., 5 in.

Precision Husky ProGrind 1000. Powered by a 240-hp Cummins with twin-disc SP214 clutch, the ProGrind 1000 features a transport length, with conveyor, of 30 ft.; a height of 12 ft., 10 in.; and a width of 8 ft., 5 in.

Precision Husky ProGrind 2000. Powered by a Cummins 450-hp NTA855 diesel engine with a 15.5-in. Wichita metallic self-adjusting clutch, the 38,000-lb. ProGrind 2000's length is 45 ft. with conveyor. It is 13 ft., 4 in. high and 10 ft., 2 in. high.

Precision Husky ProGrind 4000. Powered by a Caterpillar 650-hp 3412 DITA diesel engine, the 68,000-lb. ProGrind 4000's transport length is 42 ft., 9 in. with a height of 13 ft., 5.5 in.

Precision Husky ProGrind 5100. Powered by a Caterpillar 750-hp 3412E electronically controlled diesel engine with Twin Disk 3 plate 18-in. clutch, the 68,000-lb. ProGrind 5100's transport length is 42 ft., 9 in. at a height of 13 ft., 5.5 in.

W.H.O. Manufacturing S12-56. With engine options of up to 500 hp and weighing 12,000 lb. without engine, the S12-56 features a tub measuring 12 ft., 2.5 in. at top; 10 ft. at bottom; and 63 in. deep.

W.H.O. Manufacturing S8-43/S8-43S. With engine options of 100-150 hp, the S8-43/S8-43S features a tub width of 9 ft., 6 in.

W.H.O. Manufacturing Model P12-56. Powered by a 500-hp Caterpillar 3408 engine, the 20,000-lb. (without engine) P12-56 features a tub width of 12 ft., 2.5 in. at the lip and 10 ft., 4 in. at the base and a hammer swing diameter of 27 in.

W.H.O. Manufacturing Model P12-63-XSHD. Powered by a 650-hp Caterpillar 3412 engine, the 20,000-lb. (without engine) P12-63-XSHD features a tub width of 12 ft., 2.5 in. at the lip and 10 ft., 4 in. at the base; a depth of 60 in.; and a rotor diameter of 16 in.

Screener Basics

As described above, screeners usually work in conjunction with tub grinders. Waste recycling, mining, and forestry operations use a variety of screens. Those used in conjunction with clearing and grubbing operations are portable in configuration and specialized to the task. Portable screening units work for the separation of excavation spoils, clearing and grubbing debris, and C&D debris. The object is to remove dirt, sand, rock, and other small abrasive contaminants prior to further processing downstream. This removal significantly reduces subsequent wear and tear on this machinery. In this type of operation, screening occurs after clearing and grubbing and prior to grinding in order to remove objects that could damage the tub grinder. Screening units combine vibratory action with screen separation. The material enters onto the screen with the vibratory action causing the smaller particles to fall through and separate from the larger, recoverable materials. Debris containing larger objects, such as whole tree trunks, would not normally be fed through a screening unit.

Portable screening units can also perform postgrinding separation. Typically they are rotating-drum trommel screens that use a combination of rotation and screening to clarify construction debris, turnings, demolition lumber, and greenwaste. Diameters can range from 2 to 16 ft., while lengths run from 8 to 80 ft. A trunnion wheel or a double-stand roller chain usually drives the trommels. The tumbling motion created by the rotating drum shakes loose smaller particles that exit through the screen, leaving behind materials ready for recycling.

Screener Models and Performance

The following are specifications for commercially available portable screeners (sources are product literature provided by the manufacturer or supplier).

The MultiScreen will reduce waste and rejected material in a one-pass screening. All models have a heavy-duty design and rely upon a short trommel technology that includes a flail hammer system. This system breaks up material and blends and mixes by keeping it in suspension longer, with internal/external brushes that resist blinding to increase production. It is designed to operate in the same manner as a long trommel.

Model 470DM MultiScreen. This is a less expensive machine designed for small start-up compost operations, small landscape and topsoil contractors, and municipalities with skid-steer­class equipment or larger. It features a 54-hp John Deere diesel engine, a 2-yd.³ holding bin, a 24-in.-wide infeed belt, a 48- x 68-in. trommel screen, a pintle hitch, multiple axles, and electric brakes.

Model 605B MultiScreen. A midrange trommel, this unit features an 80-hp John Deere diesel engine, a 4-yd.³ holding bin, a 36-in.-wide infeed belt, a 60- x 78-in. trommel screen, a standard rejects/overs conveyor and 30-ft. folding belted conveyor, a fifth wheel, multiple axles, and air brakes.

Model 725DM MultiScreen. A heavy-duty machine, this model is engineered for the high-production, high-volume screening operation. It features a 115-hp turbo John Deere liquid-cooled diesel engine, a 4-yd.³ holding bin, a 36-in.-wide infeed belt, a 72- x 111-in. trommel screen, a 48-in. hopper metering belt, a standard rejects/overs conveyor and 36-in.-wide x 30-ft.-long folding belted conveyor, a fifth wheel, multiple axles, and air brakes.

Rotascreen Trommel. The tumbling action of this machine promotes the passage of undersize particles through the screen. Continuously rolling over the material bed, the Rotascreen opens up the mass to constantly expose the undersize materials to the screen surface. Designed without internal impediments, the clean design of the drum interior resists accumulations of sticks, wire, rags, sheet, damp fines, and other materials that accumulate in screening equipment. Laser alignment of the drum during assembly ensures good balance and concentricity. Engineers designed rigid support structures, access platforms, and access doors to best adapt the Rotascreen to the installation. The interior of the trommel-screen drum may be fitted with spikes for opening plastic bags of refuse prior to screening the contents. This unit is useful for granulating heavy scrap plastic sections or purgings, insulated copper or aluminum wire and cable, and a variety of other nonferrous materials.

Peterson Pacific TS 725 Trommel Screen. The TS 725 is powered by a 174-hp engine and weighs 50,000-57,000 lb. depending on conveyor configuration screen. Its dimensions are 7 ft. inside diameter x 25 ft. long with an overall length of 53 ft. with a three-conveyor option.

Daniel P. Duffy, P.E., is a professional environmental engineer with the Engineering and Environmental Affairs Dept. at Rumpke Waste Inc. in Cincinnati, OH.

MSW
March/April 2001