Plan for cover

Features - Equipment Focus | Landfill Cover

With proper planning, interim and daily covers can be designed to improve operations and save money.

June 4, 2019

Final covers play a vital role in the closing chapter of a landfill’s life. Daily and interim covers, on the other hand, are minor characters in the plot, and their importance can go overlooked. However, both serve essential functions in landfill management as they work to keep waste under wraps and quell emissions.

With the proper planning and a little foresight, daily and interim covers can be optimized to improve landfill operations and save money in the process.

Tarek Abichou, who teaches a course on geosynthetics in landfill applications at the Florida Agricultural and Mechanical University-Florida State University College of Engineering, recently spoke during a webinar presented by the Environmental Research & Education Foundation (EREF) about the importance of these covers and how to rethink their traditional composition to further benefit landfill owners and the environment.

“Landfills are built over years and years, cell by cell,” Abichou says. “All of them will eventually get a final cover, but before getting there, we cover landfills with many other covers. … The system has a function to physically separate the waste from the environment, the waste from [the surrounding community] and the waste from air.”

Cover basics

Typically, each landfill cell experiences three different cover types in its life: a daily cover, an interim cover and a final cover. Daily covers are used to isolate waste overnight; temporary covers are used during intermediate filling; and a permanent cover is placed once the landfill reaches capacity.

Abichou says regulations surrounding landfill covers are limited. For daily covers, municipal solid waste (MSW) landfill operators must cover all disposed waste at the end of each day to control odors, vectors, fires, litter and scavenging. Federal regulations require landfill operators to use a minimum of six inches of earthen materials as daily cover.

While the scope of regulations pertaining to daily covers is insubstantial, “there are even fewer texts related to the interim cover,” Abichou says.

Interim covers are to be composed of at least a foot of compacted earthen material, such as soil, over surfaces where no additional solid waste will be deposited within 180 days. Some of these covers remain in place for years.

With such limited regulations in place, Abichou believes there is room to improve upon both the design and functionality of these covers to have more efficiency and a greater purpose.

Waste-derived daily covers

Abichou says daily covers can come with several drawbacks. They consume valuable airspace and impede the movement of landfill gas and leachate. Daily covers also require extra costs to excavate, load and haul to the site.

However, some of those costs can be alleviated with alternative daily covers (ADCs) made of waste-derived materials.

ADCs can be made either with waste-derived materials or synthetic products, such as reusable geosynthetic tarps, non-reusable geosynthetic fabric, spray-on foams and slurries. While all can be effective, landfills can use resources that are accessible and readily available to do the same thing at a fraction of the cost.

ADCs made with waste-derived materials can generate revenue, Abichou says, as landfill operators are paid to accept the waste and charge a tipping fee for materials they can turn around and use to their benefit. “It’s additional revenue instead of [having to] spend money on digging soil from elsewhere,” Abichou says.

Depending on state regulations, these materials can be used as a cover either on their own or after being blended with soil—the latter of which Abichou says is typically made up of a 1-1 ratio. In some states, like California, using ADCs can even help landfills meet diversion goals.

Some jurisdictions already have a list of waste-derived materials approved for ADC use. The California Department of Resources Recycling and Recovery (CalRecycle), for example, has 11 approved ADC materials, including ash and cement kiln dust, treated auto shredder waste, construction and demolition waste, compost, green material, contaminated sediment, sludge, and shredded tires.

These materials must be processed and applied so that no gaps exist in the exposed landfill face. Jurisdictions may also approve additional materials that aren’t listed on a case-by-case basis if landfill operators can prove their efficiency to the enforcement agency during a site visit or through a written report, depending on the state.

Some materials prove more beneficial than others when used as ADCs. Sludge, for example, is attractive as an ADC both because it can divert a dense material from being sent to landfill as waste and because it can be used to augment soil nutrients to grow vegetation and minimize erosion on the cover. Auto shredder fluff, on the other hand, needs to be blended with soil and may contain contamination that has the potential to seep into the ground, at times making it more harmful than helpful.

“One has to be careful when looking at the material to use as daily cover. [You need to consider materials’] long-term effects on leachate, stability, heat, landfill gas quality, odors, etc.,” Abichou says.

Abichou says it is ideal to have several types of covers approved for use at a given facility when pursuing approval for waste-derived ADCs, as no single type of cover, whether waste-derived or not, is ideal for all sites.

Biocovers for the interim

While daily covers can be composed of a variety of materials, landfill operators don’t have nearly as many choices when it comes to interim covers.

Some landfills use tarps and membranes as interim covers, though most use soil, which Abichou says is the preferable material.

“Rethinking interim covers … as biocovers is the way to go,” Abichou says.

Abichou says the most “action” takes place in a landfill cell when it’s covered by the interim cover, so operators should be mindful of choosing a solution that works best for their site.

“I believe that interim covers are the most important cover one should talk about,” Abichou says. “Landfills stay under interim covers for a long time. … Models show that 90 percent of percolation occurs before a final cover is placed. Most greenhouse gas emissions occur pre-final cover placement. Interim covers, in my opinion, should have more respect.”

Abichou has spent years studying how interim covers made of a variety of earthen materials reduce different types of emissions.

In one of his studies, Abichou experimented with soil, mulch and compost to determine which was most effective in minimizing hydrogen sulfide. The study found soil would attenuate 100 percent of incoming hydrogen sulfide for 75,000 days—more than 205 years.

On the other hand, mulch would do so for 4,400 days, while compost alone would attenuate that volume of hydrogen sulfide for just 462 days.

Another one of Abichou’s studies focused on the effect of different types of soils on methane reduction. The study showed that efficiency ultimately depends not just on a soil’s physical and biological properties, but also on environmental conditions, such as air and waste temperature, precipitation and barometric pressure.

The study concluded that the higher the porosity, vegetation and microbial levels of soil, the better.

By making a choice to use porous, healthy soil as an interim cover, operators can effectively minimize the level of gasses released at their landfill during the most critical period of emissions.

Whether it’s investing in higher quality resources or repurposing those already in a landfill’s possession, rethinking the covers that impact landfill performance on a day-to-day basis can help increase a site’s lifespan while preserving time, money and the environment.

The author is the assistant editor for Waste Today magazine and can be contacted at tcottom@gie.net.

Green waste revolution: Why cannabis legalization means big business for haulers

Features - Cover Story

With many states legalizing cannabis for medical or recreational use, haulers are being called upon to manage a new kind of waste stream.

June 4, 2019

Adam Redling

Since Washington and Colorado became the first two states to legalize recreational cannabis use in 2012, the floodgates have opened, paving the way for legalization in the U.S. Currently, the District of Columbia and 10 states—Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont and Washington—have voted to legalize cannabis for recreational use. Including medical use, 33 states and the District of Columbia have passed laws legalizing cannabis to some capacity.

With more states expected to follow in 2019 and beyond, cannabis is already becoming a major economic driver throughout the country.

According to a December 2018 article in Fortune, “The Legal Marijuana Industry Is Soaring—And 2019 Could Be Its Best Year Yet,” the legal marijuana industry grew to $10.4 billion in the U.S. in 2018 and employed 250,000 people. In North America overall, backed by Canada’s decision to legalize marijuana nationwide, the legal marijuana industry garnered $10 billion in investments in 2018, up from $5 billion in 2015. These numbers are only expected to multiply in the coming years, with projections estimating the industry could garner $16 billion in investments this year as it continues to expand.

Expanding legalization means greater need for disposal

From seed to sale, cannabis production is a multilayered process. Cannabis plants are typically raised in growing facilities, cultivated, sent to labs for testing and then either shipped to dispensaries for final sale or processed to make products such as oils, edibles or other cannabis derivates that are then tested and sold.

With each of these stages, operation-specific wastes are produced.

Rich Thompson is a managing partner at TEC LLC, a Scottsdale, Arizona-based consultancy group. He formerly served as director of environmental compliance at Phoenix-based Republic Services and as director of environmental protection at Houston-based Waste Management. According to Thompson, while the cannabis waste stream may be unique, its organics can be handled much the same as other special wastes.

Thompson says almost all of the cannabis flower that contains tetrahydrocannabinol (THC)—the principal component of cannabis that gives the plant psychoactive properties—is cultivated and sold before the rest of the plant’s stalk, stem and roots enter the waste stream for disposal.

According to Thompson, this mitigates a lot of the environmental or contamination concerns that waste companies need to have when it comes to disposing of these organic materials.

The District of Columbia and 10 states—Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont and Washington—have voted to legalize cannabis for recreational use. Including medical use, 33 states and the District of Columbia have passed laws legalizing cannabis to some capacity.

Thompson says organic matter stemming from cannabis production can be disposed of in four ways: landfill, composting, incineration or through digestors, with landfill and composting being the most common methods.

“I would say cannabis actually disposes the same as green waste—with one exception. I know people have used green waste for a lot of different applications, including as a cover material in some landfills. Now, since cannabis is a special waste, you wouldn’t use it as cover material in a landfill, but it can be easily put in a landfill nonetheless,” Thompson says. “You’d want to place dirt on it and you’d want it disposed of as soon as possible. But when it comes to compost operations, it composts just like any green waste. It can be chopped up and mixed into the compost to make a pretty good mulch or soil. So, there really is nothing spectacular about how it’s managed [when it comes to landfill or composting].”

Beyond organic waste, cannabis waste can be composed of manufactured products such as edibles and oils and their derivatives, as well as industry-specific packaging that requires disposal.

Understanding regulations

The discrepancy between federal law, which views cannabis as an illegal substance, and individual state laws can be confusing for producers and waste companies alike. When variations between different state laws are factored in, handling cannabis waste can become even more complex. Thompson says careful consideration is needed from both generators and waste operators to ensure they are adhering to the bylaws governing their operations.

“On the generator side, most of those companies need to have some sort of a record-keeping system,” Thompson says. “What the states are saying is that they want to know the volume of materials a generator has in the facility by weight or by volume, and then they’re going to ask them the question: ‘How much of this got shipped out as product in order to be sold as cannabis, marijuana or whatever product they’re producing, and then how much of it got shipped out of the facility as waste for either disposal or recycling?’”

Before the waste can be collected from a generator, it needs to be stored on-site. Thompson says grow operations typically have regulations that stipulate the site be secure from the public by means of fencing and other security measures. In cases where the perimeter is secure from the public, waste containers and dumpsters don’t necessarily need to contain a lock, Thompson says. However, for other producers and dispensaries where waste containers may be located outside a secure area, it is necessary to keep containers locked to prevent scavenging.

Before cannabis waste is placed in containers, however, producers are called upon to render material destined for landfill “unusable and unrecognizable.” This can be accomplished by grinding the organic material and mixing it with at least 50 percent of another solid waste source, such as plastic, paper or food waste.

“It's important for all waste companies to tell their drivers that they're never allowed to scavenge loads for any purpose. If you're telling the customer their waste is slated to go to a landfill or to a compost facility, that's where it should end up.” –Rich Thompson, managing partner, TEC LLC

Thompson says that in an effort to render this waste unusable and unrecognizable as mandated by law, some operators have been found to misguidedly mix their cannabis byproducts with bleach, ammonia or other toxic substances. However, this is both unnecessary and potentially harmful to the environment.

From a hauler perspective, regulatory compliance in managing these waste sources ultimately resides with the drivers and collection personnel directly handling the refuse materials. Thompson says waste management companies need to be vigilant during hiring and training to instruct all collection staff and drivers about properly handling cannabis byproducts.

“It’s important for all waste companies to tell their drivers that they’re never allowed to scavenge loads for any purpose. If you’re telling the customer their waste is slated to go to a landfill or to a compost facility, that’s where it should end up,” Thompson says

Haulers also need to be mindful of transporting cannabis waste, especially over state lines. Thompson cites a recent example where three truckers were taking hemp, which is similar to cannabis but devoid of the psychoactive ingredients, from Oregon to Colorado. The truckers were stopped at a weigh station in Idaho and subsequently held in jail. The case is still being reviewed, but the men face five years in prison if convicted, as marijuana is illegal in Idaho and the state does not currently distinguish between marijuana and hemp.

“The Department of Transportation still regulates the haulers in terms of cannabis,” Thompson says. “The federal law says that cannabis operations are illegal, but it’s the states that have the rights to determine their own regulations in this case. So, for haulers, it is important that they know that they cannot haul cannabis from a legal state across the lines to a state where it’s illegal.”

Finding opportunities

Thompson says that cannabis-related businesses can be good customers for waste management companies. The key for haulers is being able to show these potential customers that they can handle their waste generation volumes and schedules just like they would for any other business.

“These customers are going to generate a lot of waste and they’re going to generate waste on a very regular basis,” Thompson says. “For instance, growing plants takes about 105 days from the time they put a seed in the ground to the time they can actually harvest the plant. But the way most of these grow operations work is they have a rotating cycle of plants always working through their facility. They’re trying to be in a position where they’re harvesting something nearly every week. They’re going to have a regular amount of waste that they’re going to generate and they need a very reliable service provider to provide those hauling services to them. That’s where companies need to step up and show these potential customers what they can do in terms of providing the right size bins for their operations and then what they can do to service them on their correct intervals to get that material off the site.”

Looking to the future, Thompson says that cannabis-related opportunities are rich for the waste industry. With more than half the country having some level of legalization in place currently, and more on the way, the cannabis industry is poised for an explosion that is sure to benefit haulers able to handle the demand.

“I think [the growth of the cannabis market] is an opportunity for the waste industry to provide services to a new and growing industry. From what I understand in terms of the number of people being hired, cannabis is one of the fastest growing industries in the U.S. right now,” Thompson says. “So, clearly, they have a need for people to manage their waste. Handling waste is not their business, but it’s a necessary byproduct of their operations. They need experts to come in and tell them what they need to do in terms of managing their waste and controlling the cost at the same time.”

Check out our Executive Q&A to see how Gaiaca Waste Revitalization has found its footing handling California’s cannabis waste.

The author is the editor of Waste Today and can be contacted at aredling@gie.net.

Preparing for PFAS

Departments - WASTE WATCH

June 4, 2019

Chris Lund

The impact of per- and polyfluoroalkyl substances (PFAS) on my compliance monitoring program became apparent about a year ago. PFAS—a group of approximately 3,500 manmade chemical compounds that can be found in landfill leachate, wastewater, sludge disposed in landfills and wastewater treatment plant biosolids, among other applications—have recently caught the attention of regulators intent on improving landfill monitoring.

As someone responsible for environmental compliance and monitoring of both an operational municipal solid waste (MSW) landfill and a newly closed landfill, I felt uneasy over new sampling requirements, as I didn’t know the impact these substances would have on my annual monitoring costs. Due to the contaminants’ ubiquitous presence (which presents a cross-contamination issue), PFAS are impacting post-closure budgets by increasing the costs for revised Sampling and Analysis Plans (SAP), as well as increasing costs for shipping containers, handling and reporting.

The waste management industry is uncertain about how to appropriately establish risk-based criteria for evaluating these contaminants. I contend that the first step is understanding where these substances are found in the products we throw away and how they are processed in our solid waste management systems. In addition, we need to ask ourselves how we will limit the level of these substances found in products that were made in other countries and find their way into domestic landfills.

Part of the struggle to appropriately legislate the issue is how new the subject of PFAS is to most in the industry. I recently attended a conference where PFAS were the topic of several sessions. Because much of the research on these substances is so recent, there was not a study referenced older than 2017. The relative lack of knowledge on this subject is limiting the industry’s ability to develop a consistent approach in tackling the problem.

In states such as North Carolina, where GenX (a short-chain version of PFAS) is manufactured, these compounds have been shown to impact air, surface water and groundwater alike. For this reason, a proactive multiagency response has been required to identify these sources of contamination and safeguard the public. In response to this (and other PFAS concerns in the state), North Carolina has decided to start sampling leachate at MSW landfills for these substances. They will be analyzing for perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and GenX (where warranted) and conducting a full scan of PFAS compounds on a site-specific basis.

The federal government currently has no requirement for sampling PFAS, nor an acceptable exposure level. Some states, however, are preemptively moving forward with PFAS standards and monitoring practices. About two dozen states currently have, or are considering, limits for these substances. This has resulted in varying levels of monitoring and enforcement oversight.

One simply needs to search “PFAS lawsuits” online to see how this has quickly become a hot-button issue, not unlike when the far-reaching use of asbestos caught the industry’s attention in years past. In October 2018, for example, an Ohio firefighter filed a class-action lawsuit against PFAS manufacturers in U.S. District Court. In mid-May of this year, the state of New Jersey filed a similar lawsuit.

While much is still unknown regarding PFAS’ impact on the environment, the big questions around this contamination currently are, “How bad is it, and how bad will it get?” Without a crystal ball, all we can do now is anticipate monitoring requirements, stay tuned for new legislation, research new monitoring and analytical methods and make good judgement calls in the interim. Although no one can predict the future, landfill and other waste management facility operators might consider bolstering their monitoring and compliance budgets for the long term now to be ready for what comes next.

Seeing green

Departments - EDITOR’S LETTER

June 4, 2019

They say you can’t predict the future. But when it comes to corporate America, you can follow the money trail to see where it’s heading.

In this issue’s cover story, “Green waste revolution: Why cannabis legalization means big business for haulers,” we explore how shifting legislation in favor of cannabis legalization has paved the way for new opportunities for those in the waste sector.

When Gallup first polled Americans in 1969 on whether or not marijuana should be legalized, only 12 percent of the population supported it. That number stagnated in the 25-percent range for several decades until the new millennium, when the percentage of those favoring legalization began to steadily climb. Last year, a whopping 66 percent of Americans said they supported legalizing marijuana.

As cannabis has grown more socially acceptable and politically popular in recent years, so too has the industry supporting it.

A report that the marijuana industry site Leafly and Whitney Economics jointly released in March says cannabis accounts for the fastest growing job sector in the U.S. In 2018, the legal cannabis manufacturing and distributing sector accounted for the creation of 64,389 new jobs—a 44 percent increase from the year before. This was in addition to a 21 percent year-over-year increase seen in 2017.

“Amid the roiling debate over American jobs, the legal cannabis industry remains a substantial and unrecognized engine of grassroots job creation. … In 2019, America’s cannabis industry is one of the nation’s greatest economic success stories,” the report’s authors wrote.

In December 2018, Forbes reported that cannabis-related companies raised nearly 13.8 billion last year, which was up from $3.5 billion in 2017.

One of the most significant investment trends in 2018 was a number of big alcohol and tobacco companies making inroads into the cannabis sector in North America. Constellation Brands, the Victor, New York-based company behind Corona and Modelo, invested $4 billion in the Canadian medical marijuana company Canopy Growth; Denver-based Molson Coors announced a joint venture with Canadian-based cannabis producer The Hydropothecary Corporation; and Altria, the Richmond, Virginia-based company behind Marlboro and Skoal, announced it was investing $1.8 billion in the Toronto-based cannabis company Cronos Group.

With 33 states and the District of Columbia already having laws supporting either the medical or recreational use of cannabis, in addition to Canada’s nationwide legalization in 2018, indicators point to continued momentum for all things cannabis in 2019 and beyond.

A new kind of customer requires new waste management solutions. It’s up to the waste industry to take the lead to figure out how to best meet the challenges that are on the horizon.

Check out “Green waste revolution: Why cannabis legalization means big business for haulers,” to see what waste management companies need to know about handling the influx of cannabis byproducts entering the waste stream.

Upgrading For Efficiency

Custom Content - Custom Content | Keith Manufacturing

April 16, 2019

Oregon’s Deschutes County Department of Solid Waste is tasked with managing the municipal solid waste (MSW) of approximately 181,000 residents. In 2016, this equated to 240,800 tons of garbage, all of which was sent to the Knott Landfill Recycling and Transfer Facility in Bend, Oregon. To help transport this incoming waste, operators rely on WALKING FLOOR® technology from Keith Manufacturing Co. to increase efficiency and promote safety.

According to Deschutes County Solid Waste Operations Manager Chad Centola, the county contracts for the hauling of MSW from its network of rural transfer stations to Knott Landfill with a private company that utilizes a fleet of 21 WALKING FLOOR® trailers.

In addition, Deschutes County operates an on-site transfer station at Knott Landfill and has its own fleet of four WALKING FLOOR® trailers that are used to transfer public self-haul MSW from the transfer station to the landfill roughly one mile away.

When plans for constructing the on-site transfer station were being formulated around 2004, Centola says the private transfer contractor and the county made the joint decision to use WALKING FLOOR® unloaders instead of a tipper system for easier and safer unloading.

“The other option if we didn’t implement the WALKING FLOOR® trailers was to use a tipper system, which meant accommodating two different unloading systems at the site as well as having to worry about purchasing, owning and maintaining the tippers,” Centola says. “The WALKING FLOOR® system appears to be a safer method for unloading. Another safety—and efficiency—factor we considered is there is no need to have a near vertical wall for unloading with the WALKING FLOOR® technology, whereas a tipper requires a grade separation for the unloading process.”

Centola says that the durability of the WALKING FLOOR® system is paramount thanks to the volume its trailers are tasked with transporting each day.

The county’s self-haul customers first unload their waste on a concrete floor in an enclosed building and operators use a loader and excavator to top-load the MSW into the county’s fleet of Steco- and Wilkens Industries-manufactured trailers, which are parked below the building.

“Where the rural site transfer trailers might be loaded once a day at the most, we reload our on-site trailers six to eight times per day,” Centola says. “The wear and tear the floors need to be able to absorb is substantial.”

"We like the WALKING FLOOR® trailers. When the working face is busy, they can position closer to each other without compromising safety, which also helps with operating efficiency at the landfill.” – Chad Centola, Operations Manager, Deschutes County Solid Waste

Centola says that the county is currently in the process of replacing its existing aluminum floor trailers that were purchased in 2006 with Keith’s V-9 Series steel floors for added durability.

“We are currently in a replacement cycle for the 2006 trailers,” he says. “We replaced one trailer in 2018 with a steel V-9 floor and are currently out to bid for a second trailer with a steel V-9 floor. The last two trailers will be replaced in our 2019-’20 fiscal year. I believe the V-9 floors will better suit our conditions.”

Centola says that he is confident the renewed investment in WALKING FLOOR® technology will continue to allow the county to meet its waste management needs in the years to come by giving operators the versatility they need to effectively manage the waste of area residents.

“We like the WALKING FLOOR® trailers,” he says. “When the working face is busy, they can position closer to each other without compromising safety, which also helps with operating efficiency at the landfill.”

More information on made-in-the-U.S.A. Keith WALKING FLOOR® systems, including the many applications in which Keith’s 60,000 units can be found globally, can be obtained by visiting keithwalkingfloor.com or by calling (800) 547-6161.

Plan for cover