Landfill Compaction Gets a Tech Upgrade

Best practices for landfill compaction using long-established techniques combined with new technology

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Landfill operations require expert management of many variables, but one of the most essential aspects that can make or break a successful landfill operation is how well a team can manage compaction. Getting the most airspace out of your landfill maximizes the lifespan of your site, so essentially, compaction efficiency can speed up or slow down that ticking timer that determines when your landfill can no longer be in use.

In order to get the most density out of your landfill, operators must know the best practices for daily compaction and must be constantly learning the next best technique for compaction. But what are these best practices? And how have they changed as equipment enters the digital age?

Tom Griffith, a market professional in waste applications for Caterpillar, which is headquartered in Deerfield, IL, says standard procedures involve teamwork between a compactor operator and a dozer operator.

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“Best practices rely on operators working as teams and understanding the basics of achieving density,” he says. “A proper pattern must be a logical sequence. Those that have higher density ratings normally start at one side of the working face and logically work their way across the face in a set sequence. They communicate and they work together.”

Griffith says this type of teamwork should look something like the following: Operators must use thin layers because they “compress, shred, and blend” into underlying layers. If layers are too thick, a compactor will only be able to compress the top of the layer and the rest will remain spongy, loose, and uncompacted.

“Layer height of the material will either aid density or rob density; there is no in-between,” he says.

He says the best way to increase the density of the layers initially is to make layers thin from the start—not relying on secondary compaction via vehicle traffic or degradation—and to avoid cliffing or double layering. When the layer height is at the right size, operators can focus on running at least four to six passes in pattern format, with the compactor operator and dozer operator constantly talking about where they are in the pattern and what comes next.

“Most sites when asked, ‘How many passes are you making over the waste?’” says Griffith, “answer ‘three to four.’ That’s what they’ve been taught. That’s what the operators think. In actuality, the average number of passes we see from all the site studies and training we’ve done in the past years, the average is one to two. It should be from four to five.”

He says low pass numbers only lead to less density, taller layers, and more problems for landfill operators.

“The reason passes are low is due to the fact that operators don’t team up and work in an effective pattern,” he says. “I’m not saying it’s easy. It’s one of the hardest things to do when working together and operating a compactor and dozer.”

He added that if only one operator is available to run the compactor or dozer, he or she should work in a logical pattern sequence with an appropriate number of passes to maximize compaction or else the rate of compaction really won’t be very efficient.

“If they are operating just one machine on the working face,” he says, “then it is up to the operator to keep working in a logical sequence so as to gain higher density.”

Neal Bolton, president of Blue Ridge Services, a consulting firm based in Mariposa, CA, that focuses on waste management, facility management, and environmental monitoring, says best practices also include long-standing norms, as well as new ways of doing the job due to technological updates.

“The best practices are still the same,” he says. “The new technology just helps us do that job much more efficiently.”

He says standard procedures still include tried-and-true methods like placing waste in thin lifts, working the machine horizontally, and mixing wet trash with dry trash. The last step of this method helps ensure that the paper and cardboard will absorb the moisture and will soften the wood fiber for better compaction.

“Think about crushing a piece of dry paper into a wad (compaction dry) versus crushing a piece of paper that you have wetted (compaction wet),” says Bolton.

Two technologies that have changed best practices and are helping operators to increase waste compaction at job sites today are real-time machine monitoring and drones, he says, among other technologies.

He says real-time machine monitoring gives constant updates on the machine’s condition—including engine RPM, temperature, fuel consumption, idle time, work time, and other metrics—to its operator or mechanic so they can keep an eye on the vital signs of the machine in use. These metrics would otherwise have to be manually measured or measured after the machine was done being run. Bolton says machine monitoring has become standard in the industry and each major machine manufacturer has a type of monitoring software that they prefer—he adds that Caterpillar uses VisionLink and John Deere uses JDLink.

Drones are used to observe compactors and other machines as they are working in order to gather other types of metrics that are trend-oriented, he says. Drones can measure productivity rates and travel patterns of compactors as they make their required passes to see if the passes are oriented in an efficient way—or if another pattern could speed up the job with the same number of passes.

Bolton says drones can also be used to create topographic maps that are used to regularly monitor landfill waste density. They can also create base maps for Operational Planning and Sequencing drawings during the preparation of a project, and maps to compare compaction density if different types of compactor teeth are used—this helps operators pick the most efficient teeth for the waste at a particular site.

Griffith says new technologies in these machines are useful for site surveying to cut engineering and surveying costs. Some of his clients use data from machines like dozers and rovers to do their site surveying.

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Other best practices for landfill compaction—as covered in previous articles from Municipal Solid Waste Management magazine—include pre-shredding waste and mining the waste. While pre-shredding may seem like it would actually hinder compaction because it creates more volume, it actually helps decrease density during the compaction process.

Since most landfills compact their waste in place, it’s become standard procedure to bring compactors and dozers onto landfills for daily compaction, sometimes due to environmental regulations that require this, according to a previous MSW piece by Daniel P. Duffy.

“In this method, waste is deposited at the toe of the current waste disposal slope (known as the working face) and spread over previously compacted waste,” the article explains. “Some landfills utilize the trench method, where waste is disposed of in discrete trenches. However, this is rarely done nowadays and is only suitable for landfills receiving small daily waste tonnages and whose groundwater is very deep. For most landfills, a small fleet of vehicles is required to manage the working face and ensure that compaction is performed properly. Tractor-type vehicles are useful for spreading waste in thin layers over the working face and for providing secondary compaction prior to direct compaction.”

Bolton says compactors and dozers for landfill maintenance often come with these efficiency-improving and upgraded technological features, so operators have to be trained to use these new types of machines. He says learning the basics of VisionLink or JDLink isn’t as intimidating as it might sound and is actually “relatively simple.”

“However, like anything else, learning to use it fully and effectively does take a bit more time,” he says. “And it’s also important that the user understands what he or she is trying to get out of the system—and then know how to interpret the data. For example, it’s one thing for a manager to learn that the compactor’s average idle time was 63%. But then knowing if that was good or bad, and what to do about it, is another thing.”

Bolton adds that these machines provide substantial benefits because machine monitoring can tell you a lot more about the performance of a machine. For example, if a manager notices that a landfill compactor is frequently overheating when a specific operator runs the machine, this may prompt the manager to investigate the condition of the machine when various operators are running it. If that manager then observes that machine under a different operator—or several other operators—then he or she can deduce whether the machine itself needs repairs or if the issue is human error and that operator just needs more training. This can save time and effort by eliminating the cost behind unnecessary repairs or unnecessary training, depending on which variable is actually causing the overheating problem.

Griffith agrees, saying proper training with these machine enhancements can make a big difference on a job site. He says he recalled one landfill he worked with that had a CCS900 system and the site’s operators were trained on best practices with layer height, patterns, passes, and other specifics.

“Once the site operators started utilizing the system correctly and operated in best practices, the site density improved over 40%,” he says. “Cover soil lowered more than 10%. The site manager, who was working with the office off-board part of the system, was able to not only track density and cover soil use, but [he or she] started planning with engineers [for] future cell development and groundwater runoff.”

Griffith says compactor operator training, and other machine training, is typically completed at Caterpillar’s dealerships by operators who have already completed Trimble/Caterpillar classes. He says the length of machine training, in general, depends on the type of machine an operator is learning about, but in general, training lasts from one day to two- to three-day-long classes onsite or at a dealership.

Off-board training, which is data analytics training, lasts from one day to one week, depending on the type of machines the operators are working with and how much data is being downloaded.

All in all, training never really stops because new improvements and developments require more training, so occasional education is part of the job, Griffith says.

“Learning curves for operators are basically understanding how to utilize the system and then understanding all of the capabilities of the system as they start to use it,” he says. “Operators that accept the system and its ability to aid them in their job have lower learning curves, of course. Off-board learning curves are a little longer as data starts coming in and the people working with off-board understand all of the possibilities.”

He says the learning curve for flying a drone is similar and is “relatively easy” straight away if an operator is just flying up to take a quick picture or video and then sending the drone back to its base. More complex operations require more training to gain the knowledge and experience necessary to operate the drone safely and properly. In addition, commercial uses for drones require a drone operator to be trained and certified through the Federal Aviation Administration and that operator must have a Part 107 certification, as well as follow all FAA regulations regarding where drones can be flown, both for commercial and personal uses.

The allure of working with new types of technologies in a steady industry like solid waste sometimes makes it easier to attract young workers, Bolton says. On the flip side, these types of improvements sometimes isolate older generations who are seeking work and are nervous at the prospect of learning about technological subjects.

“They may make it easier to find new operators because new technology is fun and intriguing,” he says. “However, many people shy away from change—especially when it is associated with technology. It’s sort of an old dog/new trick issue.”

Some longtime operators in the solid waste industry embrace the new types of technologies because it helps them do their jobs faster and more efficiently, he adds. However, others get “intimidated” by the technological changes and the pace of the change.

Griffith says new technologies often do attract younger workers, and these workers tend to learn the ins and outs of the technology faster than their more senior counterparts. However, mindset matters—particularly if an older operator is unwilling to learn a new skill.

“Those sites I’ve been on that utilize these systems on a machine or multiple machines who have younger operators, the younger operators tend to pick up faster and use the technology quicker than the older operators who are set in their ways,” he says. “In fact, the younger operator that is utilizing the compactor system to its fullest advantage is outperforming the more experienced operator in not only better density but less fuel [and] less time in getting the job done.”

Griffith says it’s becoming more difficult to find younger people who are interested in joining the solid waste industry, but machine operations applications do provide an alluring option for that demographic.

“Technology and the ability to ‘work smart’ does lure younger operators,” he says. “Most of them want to ‘work smarter, not harder.’ They also want to be challenged not only in learning operations but how to do the job right the first time and achieve goals. There is a difference in work attitude from the sites that utilize technology to those that don’t.”

The effectiveness of these technological improvements does depend on the mindset of the operator, Griffith says, regardless of age or experience level.

Technology can make a traditional machine more effective “depending on the attitude of the veteran operator,” says Griffith. “I would say 50% [of older operators] embrace it because it does make their job easier, and 50% believe they have the capabilities to perform the same task and get the same results.”

However, most of the time, the latter category of operators overestimate their abilities and are not able to come close to the same results without the added technology, he says.

This isn’t because these operators are not good at their job. It’s just that the added technology is like an extra hand or a sixth sense—it gives the operator an advantage that a non-equipped operator cannot hope to replicate in the same amount of time. Similar to how hydraulics revolutionized mechanics, technological monitoring and machine analytics are moving machine operations forward by providing information in an instant that would otherwise take days, months, or years to collect and review for trends. Technology also holds great potential for closing training gaps for operators by giving them at-home and on-the-job access to both general and hyper-specific training.

“I was on a site where a younger and older operator were working together and discussing a YouTube training they had seen online,” says Griffith. “Both were learning and applying what they had learned from onsite training and online training. That’s the direction current and future training is taking.”

Griffith says that members of onsite and off-board staff are using various forms of technology both for training and for workflow, and these enhancements have cut out or simplified some tasks that would otherwise be mundane, like paperwork. Onsite operators are seeing how the machine improvements allow for less downtime and less repetition due to human error.

“Most veteran operators understand they need to keep learning or they will be left behind and/or not utilized as much,” he says.

Some of the innovations that help maximize density and cut down on airspace are new ways to monitor compactors for efficiency, Bolton says. The goal is to improve this efficiency, thus reducing actual costs and secondary costs like machine maintenance and lost time and revenue from machine downtime during that necessary maintenance.

He says that Blue Ridge Services does regular assessments for landfills across North America called CORE Assessments—Comprehensive Operations Review. At first, his company would take photographs of compactors while they ran at landfills and would use stopwatches to record their productivity rates.

When video cameras became more commercially available, his company opted to set up a video camera on a tripod to record the machine’s activity, and efficiency rates for the compactor would be determined based on a careful review of that video, he says.

Then, GoPros came on the market, and Blue Ridge Services decided to mount a GoPro camera on the compactors they were evaluating. This footage was more precise and gave a better look at efficiency rates. While GoPros are still a popular video camera device today, Bolton says they didn’t stop there.

“Now we can park a drone 300 feet above the active work area and observe not only the compactor’s productivity but also see how it interacts with the machines onsite,” he says.

Griffith says technological improvements like machine monitoring, in-machine analytics, and drones often help improve density rates and can reduce the amount of cover soil needed.

Often, he says, the question at job sites today is, “How do we use this technology?” rather than, “Should we use it?”

“In many of the sites I’ve been on, technology has to have a ‘buy-in’ period by all of the team,” he says. “Then a discussion of ‘Where do we start?’ and ‘What are the next steps?’”

Among users who are implementing technologies, the questions often shift to thinking about how to tweak their usage for better implementation based on emerging best practices or new use cases.

“Those sites again that embrace best practices and new technologies are seeing results not only with increased density and decreased soil use, but also in less fuel, less maintenance, better groundwater runoff, less surveying times, less extensive planning, better teamwork, and improved safety.” 

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