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Solid waste managers are looking for constant, consistent savings. By Paul Hull It’s not so much the purchase price of a padfoot compactor or a truck that seems to concern many managers involved in solid waste collection and disposal. It’s the ability to get and maintain control over those everyday expenses that are always there but often neglected. Using the word “neglect” does not mean that managers are failing in their duties; more often it means that they are never made aware of areas where they could save money. One of the most interesting and knowledgeable gentlemen with whom we have talked or corresponded is George Baker, currently the director of fleet management for the County of Volusia, FL. He gained 25 years of solid waste truck experience with the City of Dallas and the City of Tyler, both in Texas. He sent me a list of practical steps to saving money all the time. Thank you, George! Some of the aspects of solid waste management he mentioned are those very concepts that have been neglected, forgotten, or never pursued elsewhere. “Use a hydraulic fluid dialysis machine,” observes Baker. “This machine can be used to clean hydraulic fluid during the annual truck PM [preventative maintenance]. The machine is also used after any hydraulic component failure. The hydraulic system is cycled while the dialysis machine filters the fluid down to 5 microns. This removes contaminants to prevent future component failures. The dialysis machine can reduce costs by saving 25 to 50 gallons of fluid per hydraulic repair. It also reduces the quantity of waste oil generated.” An immediate reaction from some managers is: “Oh no, not another new technology to save us.” To which the reaction of managers who have brought their facilities and fleets to good shape is: “Most of the success we have enjoyed has been due to our learning about new technologies and learning how to use them to our advantage.” The surprise for the first group is that hydraulic fluid dialysis machines are not exactly new. We contacted Len Licursi, who has been with Parker (a world leader in mobile and truck hydraulic components and systems) for 15 years and whose main responsibility at the company is the condition-monitoring product line. “We should ask customers with fleets of waste trucks what they do with the hydraulic oil in their systems when they get contaminated,” he says. “The typical answer would be that they empty the tank and refill it with new oil. That in itself could be a problem because new oil can sometimes be as dirty as the oil coming out of the system. The other issue is the cost of disposal of the old oil. In today’s world of regulation, if the waste fluid is not carefully maintained to what has been put in the waste container, the EPA and other agencies deem the whole contents to be hazardous waste, which allows the hauler of the fluid to charge more for its disposal.” (A small point, but how expensive is that?) “There are two distinct advantages to dialysis of the fluid,” adds Licursi. “One affects the cost; the other affects system performance. Years of experience have shown that hydraulic fluid does not wear out. It gets contaminated by any number of things. If the fluid is kept dry, at the recommended temperature, and the ingression of dirt is prevented, the fluid should last, and there would be no need to replace it. Unfortunately, in the field of waste truck fleets, the trucks are constantly in service and sometimes things do happen, such as hose breaks, breather caps not secure, or rod wiper seals nicked to let dirt in. All of these build up, but a little preventative maintenance of fluid dialysis on a periodic basis can extend the life of the fluid to keep the performance of the system at its peak. That translates into uptime. It has also been shown that the cost of cleaning a gallon of hydraulic oil is less than the cost of replacing the same amount, and that doesn’t count those hidden issues of adding contamination and debris when refilling.”
What we have heard is that, yes, many managers throw away what they consider to be contaminated oil and replace it with what they assume to be perfect oil. (As we in solid waste management know, ours is a throw-away society. An expensive pair of jeans gets a slight snag, get rid of them! These shoes are scuffed? Get some new ones.) If there is another way of handling this all-too-common hydraulic oil problem, we should investigate. “Not only does a hydraulic dialysis machine work, but its payback could be economically beneficial beyond the user’s expectations,” advises Licursi. “Parker offers small machines that range from small filter carts that handle a basic 50-gallon or smaller reservoir to much larger dehydration systems for large volumes.” Tracking Time and Travel Reinforcing the concept that technological advances don’t have to be huge, complicated, or expensive is the DumpMaster (another help indicated to us by Abbott Enterprises). This little fellow mounts on a container and will record and display both the date and time that the container was emptied. Aha! This is a practical answer to those customers (we all have them) who claim their containers are still full or your driver missed them. Among well-known waste collection companies that have used this small device successfully have been United Waste, Allied Waste, National Waste & Disposal, Waste Management, and Rumpke.
Life Cycle Costing “In Texas, on frontloaders and rolloff trucks, I had written tradeback agreements that paid 76% of the purchase price at the end of 30 months,” notes Baker. “This reduced truck life cycle costing by drastically increasing residual value and decreasing maintenance costs. The trucks were under a 36-month power-train warranty, so there was no major component maintenance cost. Truck downtime was greatly reduced.” What else do your workers discover at maintenance time, apart from the obvious evidence of low oil levels or underinflated tires? Repetitive truck problems are often attributable to certain drivers or to specific engine types, but you can correct such errors by making maintenance time a diagnostic time, too. If you use laptop diesel engine diagnostics to determine the cause of failures, you’ll find these software programs will reveal and record engine overspeeding or lugging, as well as overheating. Another part of maintenance that can issue good, practical warnings is the use of diesel engine oil analysis every time you do preventative maintenance. This analysis can warn of coolant or fuel dilution in the oil and, as wear metals show a steady increase at each oil change, engine replacements can be scheduled. You’ll be able to order a new engine in advance and get a replacement date scheduled. That would save downtime. Other components of refuse trucks that seem small but can save a constant, continuous amount of money are brake retarders. Everybody has seen those billboards that ban brake retarders (usually engine brakes) in some cities, but it has been shown that the stentorian noise that caused such a community reaction is more than likely to be the result of poor driving by truck operators. Brake retarders don’t have to be noisy. “On typical refuse trucks, brake life can be extended from five to 10 times,” comments Rich Ludvigsen, for KLAM America, an international maker of brake retarders. “Numerous sizes of retarders are available for different applications and vehicles, with weights of vehicles ranging from 8,000 pounds to more than 100,000 pounds. There are two styles of retarders: those which mount in the driveline area [driveline retarders] and those which mount directly to the differential face [focal retarders]. Transmission-mount retarders are more common in Europe than in the US, but they are available here as well. “The key to long brake-lining life is simply to keep them cool,” adds Ludvigsen. “Heat breaks down the material, and that can leave the driver out of control. Over the years, different companies have brought us devices such as engine brakes, exhaust brakes, hydraulic brakes, and electromagnetic brakes [sometimes called eddy-current brakes]. Engine brakes and exhaust brakes need engine rpm [revolutions per minute] to develop enough backpressure to slow the vehicle. That is typically from 1,500 to 2,200 rpm. Hydraulic brakes work well to control speed and are an integral part of an automatic transmission. Again, controlling the heat and lubrication are keys to efficient operation.”
Electromagnetic brake retarders, such as those made by Telma SA, headquartered at Saint-Ouen L’Aumone near Paris, France, make for a completely independent braking system, meaning they are not dependent on speed, rpm, or gears used in the transmission. This system provides “frictionless braking” to a complete stop. Rotors are attached to the driveshaft, while the stator is connected to the vehicle chassis. When electricity flows through the stator coils, electromagnetic fields with alternate polarities are created. Rotors passing through these fields generate eddy currents, placing a retarding load on the driveshaft. Any heat generated during braking is self-dissipated through the rotor vanes. As the driveshaft turns, electromagnetic forces slow the shaft, in turn slowing the vehicle. Electromagnetic retarders consume electrical energy but can be compensated by proper alternator specification and battery capacity. These retarders are designed to provide at least 85% of the braking power necessary to slow a vehicle, keeping the foundation brakes cool for the final stop. As mentioned above, electromagnetic retarders can extend brake life on refuse vehicles by as much as 10 times.
How do you control them? How do you maintain them? Mechanical control systems are the most common. Typically they include a contact box with mechanical switches, a dash-mounted hand switch with lights indicating that the retarder is on and in use. There are various switches available that allow the use of the brake pedal to activate the retarder and/or throttle switches for “instant on” use. Then there are electronic controls. These are typically programmable systems allowing the user the ability to change or set the amount of power being applied to the retarder (and diagnose any problems that may arise). Today there are many innovative features included in this type of control system, such as temperature and voltage monitoring, as well as cruise control for descents down long grades. The typical hand switch, brake pedal control, or throttle switches in combination are also available on this system. Electromagnetic brake retarders, such as Telma and KLAM, are manufactured for many years of life. Maintenance? It’s rather simple. The chief maintenance is to keep the unit clean and free of dirt buildup. Weighty Problems? Your refuse truck operator can have an idea about much garbage he can pick up because his route may follow a set pattern. For residential collections in some municipalities, the winter weight and summer weight can be significantly different. Winter garbage from a house tends to be lighter (even as much as 50% lighter) than the summer version, when natural, heavier contents are included. And then it starts to rain! A compactor can squeeze out some of the water, but it is not impossible for a rear-loading truck to be overloaded up to 10,000 pounds before it runs out of room. To counteract this, it is common practice to send trucks and trailers out at 5% or 10% below weight rather than risk the penalties of excess weight. More than one method of weighing is used in the solid waste industry at waste transfer stations. The truck may be weighed after loading. A wheel-loader will push or load waste materials onto trucks [or railroad cars], and the trucks or railroad cars are then weighed at a scalehouse or railway scale. If a truck is overloaded, it will probably involve the manual removal of excess material. If the bucket of the loader is used as a compactor, the likelihood of damage to the trailer is great. The same costly ramifications can come from weighing the truck while loading (especially that one about damaging floor scales if the loader is pounding the load). You could, of course, weigh each loader bucket before adding it to the truck if you used a system from a manufacturer like Loadrite. The weight would be known before it goes onto the transfer truck, and overloading would be eliminated. The damage caused by a loading-and-compacting process would be avoided. There are several advantages (practical and profitable) to using a Loadrite scale. Loader operators can know accurately how heavy the waste material is before that material is placed on the truck. Materials can be mixed to produce the maximum payload for each truck; you could mix heavy materials such as construction debris with lighter materials like cardboard. Loader operators can load the truck right the first time, to the legal limit, without any need to reload or reweigh. Is this accurate weighing worth the effort? A transfer station in a southeastern state used a Loadrite scale to maximize its loads by mixing correctly the household waste with the construction-and-demolition waste so it could get the most average weight per truck. It had no idea of the truck load weights and was underloading trucks to prevent overloading them. The best the station managed was an average of 18 tons of truck before installing the Loadrite. Now it averages 23 tons per truck by knowing the weights as they are loaded into the truck. The savings? This transfer station has been saving $8,000 to $9,000 per month. One of the advantages of using such technology to meet the full legal capacity for your trucks is that you may require fewer trucks (and drivers) because the number of truckloads required for efficient operation is lower. Five trucks can do the work of six, and there are fewer trips to the landfill. As the move toward fewer, smaller landfills and more, larger disposal sites at greater distances from cities gains momentum, so more transfer stations are required and built, and the importance of truck weight grows in a parallel manner. Similar to transfer stations are MRFs, with the difference that they recover material to make products. At a MRF, a system like a Loadrite can log the trucks in and out of the facility, send all relevant data to the billing system, track the sources of arriving materials, and keep material inventories. Yes, all that. That’s what “technology” can do for us in solid waste management. It does all the jobs that may have taken several people, and it does them with accuracy and permanence. With any technology of this sort, you must weigh its cost against all the expenses it saves, not simply direct expenses like labor but also those hidden expenses caused by inaccuracy or human error in calculations and reporting. At a MRF, for example, the weighing (or scalehouse) system records deliveries of loose tonnage of plastic, fiber, newspaper, glass, aluminum, and other materials. As those materials are baled or prepared for sale, an operator records estimated weights of processed units. If, say, your average bale of newspaper weighs 1,500 pounds and the MRF makes 10 bales, 15,000 pounds are added to the finished goods inventory and deducted from loose tonnage. Heavy Vehicles “One of the most popular features of trucks with our Haulmaax suspension systems is the quality of the ride,” adds Remus. “Drivers have praised the comfort and stability, whether the truck is loaded or not, whether it’s traveling on city streets or off-highway. The integrated shock absorbers control axle hop, too. From the aspect of life cycle, these Hendrickson suspensions have fewer lubrication parts and fewer moving mechanical parts. That all points to longer life.” The improved ride, of course, means less vibration and road shock, while the equalizing beams distribute the load equally between both axles of the vehicle, beneficial on uneven terrain (like the average approach to a landfill). That, in turn, means fewer repairs in the longer service life. With equipment of the size we are used to in solid waste management, it’s easy to look at the whole vehicle or machine and make decisions according to that main appearance. Many of the components that can help reduce the costs and headaches of operation are hidden in or under the vehicles, so it is too easy to ignore them. Retarders, suspensions, dialysis machines, and scales are not always visible, except in their results. Before purchasing what looks like the best (and it may very well be the best), it pays to investigate some of the products available that can make your well-chosen equipment work better for you. Paul Hull writes on construction topics for several magazines. MSW - September/October 2007
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