The Landfill Next Door

Landfills that were once considered on the outskirts of the communities they served may in time find themselves surrounded by newly developed commercial or residential communities seeking the same proximity to transport and spacious accommodations that once made the area an ideal site for hauling trash.

As communities edge ever closer to landfill locations, being a good neighbor requires ever more attentive and careful management. It doesn't matter who was there first, maintaining good relations with their host communities is a major goal of landfill operations. Added to that, growing public awareness of environmental concerns such as litter, pollution, greenhouse gases, and regulations on one side, and increasingly versatile technologies and new insights on the other, presents a fertile atmosphere for forward thinking management strategies.

Against the wind

Whenever trash is exposed to the open air there is the potential for the unhappiness of windblown litter. It is a big deal because it is the first negative thing people see and could easily become the basis for their overall perception of the landfill.

However, Neal Bolton, a consulting engineer with 36 years of experience in the landfill industry says, “Litter problems can be easy to solve.”  He said while neighbors have an obvious interest in the issue, “Most states and localities also want to see some form of litter control, although they don't always specify what type.” 

Nonetheless, he says most attentive and progressive managers put up litter fencing using a two-stage strategy. The first stage is to have good screens where the trucks unload. The second tier of the strategy is to have litter screens on the perimeter of the facility. “These would be big, up to 20-foot high, fences to capture any litter before it gets off site,” he advises.

Ruben Rosales Jr., Vice President of Coastal Netting Systems said, “Landfill managers are typically aware and savvy. They know when they need one of these fences. And when they do, we'll be there.” He says he gets requests from customers who were once a considerable distance from housing or freeways, who now find commercial and residential development edging ever closer to their sites. He's seen cases where a landfill is being established in an area in tandem with plans for residential or commercial land uses. In these scenarios good fencing makes good neighbors.

Typically, Coastal Netting Systems provides a layout with poles 50 foot on center. “We have an outside engineer with a basic litter fence calculator who provides our pole design layout. We would ask about conditions at the site and what we're trying to contain. At the top of the poles there's an option for outrigger arm with attached fencing that can catch the litter if it blows straight up, so it hits that and bounces back down. Or they can install just a straight vertical pole.” If the area is on a slope, that can make a difference in the pole design. “We look at an overview of their site to see if there are any exposures that we need to take into consideration. For transfer station areas, we design it so that it's accessible, so they can move in whatever vehicles they need to bring in.”

The netting is one-inch mesh of either golf netting or polypropylene. The frame members are steel posts stuck in the ground, with hardware typically attached by carabiner or hog rings, he explains. “We can make the poles in two pieces, so if the wind direction shifts, they can have the bottom portions strategically anchored in advance, and they can rearrange the configuration by just stabbing in the top portions into the bottom in the alternate location.”

The company also provides portable litter fence units that can be towed with a galvanized shackle or by lifting them individually with dozers. “They are easy to move around based on the customer's needs.

“We design for 50% litter load. I've never seen an issue with that because well-run landfill operations typically go out and remove any trash building up on the fence as part of routine maintenance long before it gets that high.”

Cool and compact

In addition to fencing for litter control, “It's imperative that you have good compaction,” says Alex Papp, Manager, Landfill Products for BOMAG.” Compaction, he says, plays a role in litter control by forcefully compressing the trash as it's being spread on the working face.

But compaction plays a wider role in the landfill. Papp says many landfills are plagued by issues due to a legacy of past practices. “What you're seeing are issues from poor compaction over long-term periods. You're getting slough, water intrusion, internal fires. That's because most landfills, before compactors, were using dozers. Dozers don't have the pressure to provide the weight to remove the air voids from the working face. When you're building the mountain of trash and the material is decomposing, these voids are allowing air spaces. Oxygen gets in there, you get a lot of heat in there from the decomposition and the weight and you create a fire.” Good compaction helps prevent these kinds of issues, he said.

Papp explains, “Our machines are designed with an articulating oscillating joint that allows all four wheels to stay on the ground at all times. We lead the industry in the number of teeth on the machine. That gets more ground penetration and more ground contact on the trash surface to get the compaction you need.” Even with these advantages he says neatness is a virtue. “If the wheels are gunked up with mud and trash, that will make it hard to roll out the trash on the surface. It's like a with a rolling pin if it's covered with dough sticking to it how are you going to be able to roll out that dough? So, we have scraper bars on our machines to keep the wheels clean.”

“If you have good contact surface and good compaction, you're not going to get the paper and debris flying around because you'll be compacting the trash to a point where it's sticking to the next item,” Papp said. “If you can place the material down and go over it with more material, and it’s getting kneaded in correctly by the compactor, you're keeping that material in place and it's not going to be picked up and blown away.”

A tarp-down process

Although Neal Bolton says most of the litter problems generated at a landfill occur during the busy dumping phase, rules from above, such as EPA rule subtitle D require all landfills to cover the working face when no one is at work. It's called daily cover and it's applied to contain the working face overnight. This cover material can be comprised of 6 inches depth of compacted soil, or some alternative material specified to perform at least as well in containing trash.

Marlon Yarborough, Sales and Marketing Manager for Tarpomatic, says compared to soil cover, the tarp system his company provides saves labor and air space as the landfill rises, along with helping the landfill meet federal requirements and litter control goals. Tarpomatic Automatic Tarping Machine rolls the tarp out to cover the trash overnight and spools it back in when work resumes on the face. The tarps are chain and cable weighted throughout their perimeter and in the middle to keep them in place under strong winds.

“Our tarps are coated to trap the odor underneath and they are flame resistant as well.” Tarpomatic also offers an option of a system with a deodorizing spray, so in the morning when the landfill removes the tarp, the deodorizing system sprays the working face to counteract the smell that has been compressed under the tarp overnight. “It's really to catch the initial burp of gasses when you take the tarp off.” Yarborough said.

Funky breakdown

“Odor complaints are very immediate—the wind shifts and people are like ‘dang, that smell,’”  said Parker Dale, President of Bio-Organic Catalyst. In his view, “Odor complaints are actually an indication that the management needs to be improved of that facility.”

“There's a lot of pressure if your neighborhood has that rotten egg smell,” Dale said. “The really bad smells are made by hydrogen sulfide and generated in anaerobic environments. In leachate you often have a lot of sulfides because things are being broken down and there's no oxygen in the covered material. We work at that by reducing the sulfide to a more bio-available form through oxygen transfer.”

“Our technology is tied to the production and our compositions of highly reactive nano-bubbles that transfer oxygen. We use oxygen transfer through the nano-bubbles to neutralize odorous compounds in the air column. It has the capability to neutralize hydrogen sulfide and ammonia. It's all tied to enhancing the oxygen transfer and it augments the system you're deploying. That same mechanism is incredibly effective in odor control if you're creating a misting system on airborne odors.”

In leachate treatment, he said, Bio-Organic Catalyst technology helps augment and accelerate the wastewater treatment to get oxygen transfer to combine with the sulfide component in the water. “That will produce more of a sulfur compound that is more bio-available to microbial processing. It's taking a toxic compound that would kill the biology and turning it into more of a nutrient for those same bio-organisms,” Dale said. “It's a chemistry when it goes into liquid. It forms in turbulence or aeration, nano-bubbles that attach themselves to organics and start to break molecular bonds, but the underlying mechanism is oxygen transfer. When dealing in waste you want to break the material down into more elemental states because it's then more available to the organism biological processes.”

“The old model was to make money off the dumping fees. And then as you had renewables, the value of the gas was recognized and better management began to seep in and you had the evolution of the industry and more sophistication in management to support the mechanism of action that was really biological. Now it's about optimizing the carbon cycle to essentially turn the whole thing into useable converted waste, producing useable resources such as compost and methane.”

There has been an evolution in the sophistication in the industry which was once more equipment-driven. Now you're trying to drive the conversion through biology. Dale says with Bio-Organic Catalyst's, Eccomate and Eco-Cat, “biology is what does the work.”

Dale says Bio-Organic Catalyst has had considerable success helping to convert New York City's massive Fresh Kills landfill into a park and restoring natural habitat at the site.

Taking charge of odors

Nevzat Turan, has been involved in the landfill industry for the past two and a half decades. He is President of Weaver Consultants Group. With the acquisition of GOC Technologies now the company offers a custom-engineered odor-control service that directly targets and neutralizes the chemical makeup of the noxious compounds responsible for foul smells. It's an application of the principles of chemistry. The goal is the deactivation of the compounds that create the bad smells by transforming them into harmless salts of their former selves.

According to Turan, most of the chemicals that are perceived as unpleasant by the human sense of smell are composed of molecules with a molecular charge. These charged molecules entering our nostrils have the ability to leave on our olfactory senses, a quite negative impression. If that chemical charge can be neutralized, the odor is neutralized right along with it.

But the challenge is that landfills are open spaces on the move, covering vast expanses, not just horizontally, but also vertically from bottom to top of the working face, Turan says. That makes it a bit more challenging than something like a chicken processing facility or wastewater treatment plant that generally lack the vertical dimension. Additionally, waste can be comprised of any combination of materials, any of which might contribute to odors.

To solve the first challenge, Turan said his company has highly skilled chemists on staff and has had a collaboration with University of Texas Arlington to analyze the causes of odors. “We can collect samples and figure which are the odor causing chemicals. We can speciate any kind of smell, and we can customize odor control to match using a proprietary amino acid analogue blend. It converts the odor-causing chemicals through a complete chemical reaction to an odorless salt.”

To deal with the second challenge, Turan said Weaver Consultants Group's odor control systems can be built to any scale. Along with a portable system for controlling odor on the working face, he explains that Weaver Consulting's stationary dry vapor systems are supplied by pipe between 1,000 feet and 5,000 feet in length, perforated at intervals with calibrated simple openings so the pipe has sufficient dry discharge saturated with chemical vapor, to address the odor problem over the entire length of its transit. These systems use blowers to generate air flow with flow rates up to 3,500 cfm.

Because of the two-micron particle size achieved through the vaporizing process, there is no ceiling to the vertical elevation of the treatment area.

The application can be configured to surround the landfill at its perimeter like an invisible wall. In portable configuration, its formulations, either water-based or dry vapor-based, impelled by 50k cfm fans, can be sent aloft to intercept and neutralize any odor-causing constituents in the air column before they impact the neighbors. Turan says the company has scored a number of notable successes.

He says their odor control systems have been deployed to projects such as a site operating next to a billion-dollar commercial and residential development and another next to a park with soccer fields and public games.

In addition to deploying an effective technology, Turan says, “The keys to controlling landfill odor are to identify the topographical condition and climate conditions and be prepared for changing conditions. It's very different dealing with odors at 5AM than at 2PM.” Most importantly, he said, “It takes a team that includes everybody with the recognition that odor control is just for incidental odors, but it cannot replace a well-managed gas-collection system and a good leachate-control system.”

Under pressure

Austin Phares, Regional Sales Manager for Humdinger equipment the North American distributor for Tana Oy said, “The more efficient and quick you are as a team spreading the material on the working face and packing it down, the less likely the wind will pick it up. Keeping litter on the face of the landfill is the best thing you can do for litter control. All of it is part of proper maintenance of the facility.”

Compaction can also play a role in methane production. “If you're talking about methane, the biggest thing is to get better compaction and more consistent compaction. That is going to help produce the methane. You have more and more landfills where methane is not a problem because they've turned it into a gas to energy plant,” Phares said.

Humdinger provides five different models of compactors. Tana H555, which is the heaviest in its line, and the Tana H380, which is in the middle in terms of weight, make up 80 - 85% of their market, Phares said. “Our landfill compactor is designed with two full-width drums with 110 teeth in the front and 110 teeth in the back designed to compact the trash and get a nice, neat pattern.”

When building out a methane collection system he said engineers need to calculate how much is going to be produced as the trash is going in. “You have to predict how much methane is going to be produced on an ongoing basis and then run your pipes accordingly. The more consistency you can get, and the better compaction you can get, enables you to be more efficient running your pipes and to produce more methane over a longer period.”

“As you cover with the daily material that you can pull that back off, if you do that properly, the leachate will go through the full landfill properly. It will create that methane gas and you'll be able to harness it. For that you need a piece of equipment that will create a uniform finish which our compactor does very well to limit the amount of cover soil that you're using and that will allow you to remove it the next day.”

To enhance the reuse aspect of waste, he said Humdinger’s shredders can shred mattresses and tires and wood. Phares said, with a permit, landfills can use that as alternative cover. “So instead of covering with dirt you can spread this material and get better density results and that still allows for the leachate and the methane to go through. Other companies make tarps or foam materials that dissolve, so finding some of these alternative covers can help with methane production as well.”

Holding back the rain

The treatment of leachate is one of the major long-term tasks for a landfill. The more leachate generated the higher the burden of the task. In some instances, leachate volume and quality become so extreme that local municipal treatment plants decline to accept the landfill’s output for treatment, leaving landfill operators in a tough spot. To meet regulations, they may be compelled to haul leachate for miles, perhaps encountering opposition from neighboring jurisdictions through which their haulers must transit to a distant treatment site, not to mention the expense incurred in the transport.

Leachate has two main sources: the liquid component of waste collected and delivered to the landfill, and moisture in the form of precipitation that falls on the working face. Little can be done to control the liquids the public decides to dispose of in the garbage, but effective application of landfill tarps as alternative daily cover can keep the contribution by rainfall to a minimum.

TarpArmor produces a self-contained tarp deployment system for placing and removing landfill tarps from the safe confines of the host equipment. The tarp is made from a proprietary blend including fire retardant materials and UV inhibitors to extend its life. This is particularly important to some landfills that are allowed to use tarps as cover over a period of 60 days. “It's very long wearing and durable with a lifespan of three years. And to help control leachate volume, it sheds 90% of the water from rain,” said Shannon Harrop, Divisional Vice President of TarpARMOR.

Harrop said the company's Tarp Deployment Systems contribute significantly to providing a safe and efficient daily cover operation. The tarpARMOR TDS XS-series of deployers are fully operational from the host equipment cab. The dozer or compactor operator can control the engine, exchange spools, and roll or unroll tarps all from the safety and comfort of the cab by one operator without additional ground support,” he said.

Using the TarpARMOR system, Harrop said an average landfill handling 3,000 tons per day can cover a working face of 150 by 100 feet in 30 minutes or less.

The smell of dollars

The biggest complaint about leachate arises not from the public annoyance at odor coming through the window, but from the landfill operators and the municipalities, themselves watching money fly out the door. “Managing leachate in compliance with regulations is an ongoing operational concern,” said Casey Cammann, Chief Marketing Officer at Heartland Water Technology.

He explains, “These arrangements for treatment are usually worked out between the landfill and the treatment facility.” But there is a cost for disposal and treatment of leachate, and there is a rising concern over the potential of being cut off by the local treatment facility due to excessive leachate volume or waste material incompatible with local treatment protocols. All of these factors introduce uncertainty for landfill management in operational procedures and finances.

Cammann says Heartland has a solution. He says, “The Heartland Concentrator is an onsite treatment service using evaporative technology to reduce the volume of leachate which can allow a site to better control its own destiny.”

The driver for the technology is thermal energy, whether waste heat from machinery onsite, or methane captured from the site or some other heat source accessible to the facility. The system takes whatever thermal source is available and “is uniquely designed to put leachate in direct contact with thermal output in a continuous process, feeding leachate into the hot gas path in a turbulent fashion.” It can achieve a 97% to 98% reduction in leachate volume, he said.

“The idea is to reduce the amount of leachate and be sure to have a long-term solution so landfill operators are not caught by surprise with a constraint on their disposal options. So finding ways to avoid that is an important thing to think about,” Cammann said.

David Richardson writes on science and public policy and is a frequent contributor to Endeavor Business Media publications. He is based in Baltimore, Maryland.