Spreading Thin Is A Good Thing

For landfill managers, keeping a region’s trash and waste contained takes expertise under unforgiving conditions. A job like that requires durable geosynthetics to keep waste in its place.

Geosynthetics in landfill management and construction have made it possible to construct landfills with specific grades and heights, all the while maintaining control of its stormwater and leachate runoff. Advancements in geosynthetics have given landfill operators greater flexibility when choosing products to purchase and have provided stronger, longer-lasting products that make landfill managers’ lives easier.

“Now you’re able to put proven long-lasting geosynthetics over the top of landfills, and it’s just commonplace now, where 20, 25 years ago, you hardly ever saw it,” says Marlon Yarborough, sales and marketing manager for Tarpomatic Inc., based in Kenton, OH. Tarpomatic manufactures an alternate daily cover system that attaches to a blade of construction equipment such as a dozer, an excavator, or other similar heavy machinery.

Within the harsh environment of landfills, geosynthetics are used for grading control, daily cover, stormwater runoff management, and keeping waste in place during large storm and wind events, among other uses. Over the past decade, innovations have caused geosynthetics to become tougher, more finely woven, and manufactured in a way that ensures a more consistent quality, according to Todd Harman, president of Hallaton, a Sparks, MD, company that installs geosynthetics.

“The materials have gotten better. The materials are reaching the numbers they need,” he says, noting that today’s geosynthetics are able to reach better compressive strength and water flow statistics than the geosynthetics of the 1990s or 2000s.

“Our qualities that we need are strength, high UV, durability, and we like to have it water resistant and flame resistant,” he says.

Even among modern companies, the specifics of geosynthetics and their auxiliary products vary. Yarborough says his company provides a 20-mil, 9.5-ounce woven coated polyethylene for daily cover using 2-mil coating on each side.

Harmon says his company uses a tie-down product called Anchor Down, a ballasting material. He said many landfill managers will use sandbags and ropes to hold down tarps during storms. But ahead of Hurricane Florence, a client in North Carolina needed to secure part of the client’s geosynthetics, and Harmon recommended Anchor Down as an option. After the storm, the client found that the areas secured with sandbags had been whisked away by the strong storm and material had been scattered to the winds, but the areas that used Anchor Down were still in place.

Krista Willey, vice president of marketing for Watershed Geo, a geosynthetics company based in Alpharetta, GA, says in an email interview that a “vast majority” of the landfill industry still prefers soil cover, even though it is more expensive and harder to maintain than modern geosynthetics. “Surprisingly, the vast majority of the industry continues to use the same method originally defined in 1984, despite wide recognition of the limitations and high rate of problems associated with it,” she says.

She says her company invented a new type of geosynthetic called ClosureTurf, which is a geosynthetic turf system that has an impermeable base layer with engineered turf on top. This makes it possible for a landfill to still look like it’s covered in grass, but the waste is contained underneath and water is directed as needed on top of the base layer.

The geosynthetics of yesterday weren’t strong enough and were delivered with inconsistent results, Yarborough says.

It’s important for a product to have a “tight uniform weave of the tapes, and having a reputable company that is able to give us a consistent product. I’ve seen products come through [my] last job at a warehouse, and they’d look great. And you’ll roll them off 20, 30, 50 feet and you’d have delamination,” he says.

Delamination requires operators to cut out the unusable parts of the tarp and to heat seal it back together with other usable pieces. While this may sound fine on the surface, the weakest part of a product is those seals, so while they may be a workable option, they can significantly lower the lifetime of a tarp in the long run.

“That’s the biggest thing is having a consistent product so you aren’t having to cut out big chunks of fabric,” says Yarborough. “We don’t want to have to go put seams in. It degrades the fabric. [….] It’s always better to have one continuous piece rather than having to piece tarps together.”

Willey says modern geosynthetics outperform soil cover in nearly every criteria.

“Given that it has been over 30 years since the prescriptive cover was originally defined, should we not expect that technological improvements would develop that would allow us to accomplish the primary objective of a long-lasting environmentally-sound encapsulation and cover method?” she says.

Harmon agrees that today’s geosynthetics are better than the products from a decade or more before. He says more suppliers and installers have entered the industry, but there is still a growing shortage of suppliers and installers. The wait time to obtain a geosynthetic product could be 6 to 12 weeks due to this shortage. He says this is partially caused due to the fact that it takes a team of experts to create today’s geosynthetics and “it’s hard to just jump into this because of the experience levels you need,” he says.

Even the techniques and access to quality data about product performance has improved over the past few years, Harmon says. He says landfill managers today can download data on the specs of the tarps they want to buy, and they can monitor the performance of their geosynthetics over time.

Harmon cautioned that additional monitoring can be quite helpful, but over-monitoring to an unhealthy point can cause unnecessary repairs and prescriptive measures that do little to improve geosynthetic quality but cost a good bit of money. However, a healthy level of monitoring can help detect leaks before they happen, can help with tarp replacement schedules, and can help a landfill manager predict his or her budget for the coming year.

Yarborough says these innovations largely came about because of client demand. Sometimes the demand was simply due to economics. Other times it was to meet a new regulation or to solve an existing problem that had long frustrated their industry.

“Customers wanted better products. So in turn you take the customers’ suggestions, meet with the suppliers, and come to a happy medium,” he says. “You work on it until you get something that works well and isn’t cost-inhibitive.”

Harmon agrees, saying customers wanted better products, and companies wanted to be able to sell better products.

“It’s just a lot of work, a lot of jobs, a lot of failures,” he says.

“You have a slope that fails—everything falls to the bottom,” he says. The next step is to access “Ok, what happened?”

Harmon says better geosynthetics have made his company more competitive and given them a better bird’s-eye view about where their specialty lies. He says he knows how much his geosynthetics can withstand, so he knows which contracts to go after and which ones to leave alone.

“We know what sites we can go after,” he says.

He says “problem sites” like slopes with 1:1 ratios at 45 degree angles aren’t his forte, so having a better sense of his geosynthetics gives him the ability not to overreach.

He says better geosynthetics have also permeated the industry, so quality is fairly consistent across the landfill management industry. He knows when he goes to another coast, he’ll find similar specs to other jobs sites he’s worked. This makes it so that there is a robust cadre of general contractors who are ready to install and utilize geosynthetics, rather than a smattering of inconsistent products across the industry that makes it difficult to train quality installers.

“It should make for an easier job, a more consistent job,” he says.

Yarborough says better geosynthetics makes it simpler for his company to get their jobs done at a higher standard. If they develop an even better geosynthetic, that also gives them a leg up against their competition since landfill managers are always looking for better geosynthetics.

“It helps us because we’re able to advertise, and we advertise a stronger product, a longer-lasting product, and we’re able to give references […] of people that are using our product,” he says.

Some of the most complex and difficult parts of being a landfill manager are containing, treating, and controlling leachate. Newer geosynthetics make that process simpler compared to decades past, Yarborough says.

Some of these innovations came about due to environmental regulations. As leachate became more of an issue and laws protecting drinking water quality, such as the Clean Water Act, became law, landfill managers have had to be even more diligent in protecting their community’s resources.

He says the water resistance that today’s product provides can redirect water to specific locations. The water resistance ensures that water won’t leak through the tarps, and better quality materials ensure that seams won’t give out and cause regular leaks on the working face of the landfill, which can be difficult to manage and can cause smelly odors to waft into local communities.

“Just using geosynthetics, you’re able to maneuver the water wherever you want it,” he says. “You can direct it where you want it to go, so you are able to direct it toward areas where you won’t have to treat it as leachate.”

Harmon says about a decade ago, it became possible with geosynthetics to be able to recirculate leachate and to keep biocells churning. This was a significant advantage over the old method, where leachate would drain to the bottom of the system, drain to a sump or other storage area, and get pumped out or recirculated back into the system.

Willey says one of the big problems her company wanted to focus on is managing leachate. Their ClosureTurf product addresses this issue by giving landfill managers the chance to close off specific areas into smaller cell phases, incrementally isolating areas for leachate collection to better control gas and odor.

“The quicker a cell is closed, the less infiltration resulting in less leachate generation and disposal,” she says.

She says Watershed Geo has tested this product on 1,500 acres and enacted university-level and ASTM (formerly known as the American Society for Testing and Materials) lab evaluations to test the quality of this leachate ­management system. She says their system had a leakage rate of 40 times less than soil prescriptive cover and an erosion rate of 1,000 times less than soil prescriptive cover.

Harmon says there are real-world impacts to messing up a job when leachate and water leaks are concerned with the landfill management industry.

“If you’re lining a goldfish pond and you leak, who cares?” he says. But if you have a leak at a landfill, you’re introducing hazardous materials into the soil underground, which may be connected to a local aquifer that the community relies upon for drinking water. If that is contaminated, there is no going back—contaminated aquifers cannot be cleaned at the source, and treating contaminated water for decades or more can be disastrously costly to municipalities.

“If you leak, it’s a major problem,” he says.

He says cases of energy companies not properly lining their effluent containment areas, which caused the water to leak into the surrounding soil, prompted fines of millions of dollars against individual companies.

“One: you’ve contaminated drinking water. Two: You’re getting hit with very large fines,” describes Harmon. In addition, you can’t use the system you’ve already installed for leak protection since it doesn’t work, so you have to tear it up and pay to start again. It’s a nightmare situation for any landfill operator and one every manager works daily to avoid.

The lesson is clear: Mistakes or lackadaisical attitudes around leaks can lead to irreparable harm and bankruptcy.

Managing landfills is no easy job. Perhaps no one would say it stinks—pun definitely intended—but it is a dirty job with little room for mistakes. Modern geosynthetic materials make this job a little simpler by providing cheaper, stronger daily cover versus soil cover and can help manage the complex task of leachate control.

New products are being invented every year, thanks to customer demand and market needs. Slowly but surely, the older, less-effective methods of daily cover and leachate management are giving way to a new era of landfill operation that is cleaner, greener, and less expensive than yesteryear’s sandbags and soil.