Dust—it’s everywhere, and seems to accumulate literally from thin air. It seems harmless but it is anything but that. Dramatic photos that captured the devastation of the central plains Dust Bowl of the Great Depression are compelling evidence of how dry, vulnerable soil, transported by wind, transforms the landscape.
While we have learned much about controlling dust since then, dust is still with us every day. Whether it’s on your furniture, billowing from a construction or industrial site, or making your drive home on a country road hazardous, dust is a pervasive and unwanted fact of life.
But industrial dust is far more troublesome than the stuff on the dining room table. As these particles settle on waterways and vegetation they can harm the environment, and when inhaled by wildlife, livestock, and humans can cause respiratory distress. Numerous chemicals and hazardous materials that become airborne as a byproduct of commercial operations are also downright deadly.
The effect of dust from industry or commercial operations is further intensified by the conveyances taking their commodities to and from railheads or other destinations. The result is that over time, dust takes its toll as road surfaces literally blow away, contributing to erosion and frequent, costly surface repairs.
For decades, mitigating this nonpoint-source dust—”fugitive dust”—has been a daily nuisance. On mining, construction, demolition, and agricultural sites, at scrapyards, and on countless miles of unpaved roads across the country mitigation was routinely performed with water sprayers and hoses, often with added chemicals that in themselves were environmentally undesirable. “Keeping the dust down” was an inexact science. But with the passing of the 1970 Clean Air Act and 1972 Clean Water Act (CWA), fugitive dust was subject to increased regulation. Technology rallied to develop better methods and innovative products that today are key to controlling dust.
Engineering Dust Control
“The year 1975 was in a way the birth of the modern dust control industry,” says Bob Vitale, founder and CEO of Midwest Industrial Supply Inc. in Canton, OH. With the advent of the CWA, “A need arose for products to control dust that were non-dangerous to use, and non-harmful to human health.” But controlling dust requires a complex analysis of each situation, explains Vitale.
“For example, when you are a evaluating a situation such as dust coming off a road, you need to know several factors. How many miles are affected, how well is the road constructed, what are the materials the road is made out of? Then you need to know details of the road traffic. How many vehicles travel each day? How fast are they going? And how much do they typically weigh? These are a few of a number of data points that must be defined to know how the level of dust is generated and then to very deliberately define the type of dust control you want.”
Vitale’s company manufactures a number of products for dust control, such as Soil Sement, EnviroKleen, and EK35, each “with a different chemistry to fit a specific capability.”
“The polymer emulsion and binders of these products have tremendous engineering properties, and are within the field of nanotechnology,” he says. Vitale explains that the products are designed to “coat and bind all of the small particles and hold them together.” In effect this allows the treated surface to withstand wear, and as the products are water and sun resistant, the surfaces are very resilient to climate and weather.
“Our whole approach to solving dust and erosion is to keep the road where it belongs. All of our solutions are designed to work with the customer to find what process will work best to keep it that way.”
From roadways to runways, more than 35 specialized products provide users customized dust control. And controlling dust, in some instances, can literally save lives.
Keeping the Surface Grounded
While the term “staying connected” implies having a strong Internet connection, for some it is more literal. In Alaska and Canada, the climate poses challenges to transportation, and many remote areas depend on air transport using gravel runways for everyday necessities. However, the severe climate and low daylight levels for many months make it challenging to maintain the surface of these gravel runways. Between freeze/thaw conditions and the stress of landing and takeoff of heavy aircraft, frequent breakdown of gravel runway surface is unavoidable. But loose gravel is a hazard, as it can damage aircraft, cause a breakdown of the aggregate, and create dust that impairs visibility for pilots and settles on nearby villages. Drainage problems and subsequent erosion also create a safety hazard to aircraft and surrounding communities.
To preserve these runways, Midwest implemented its Runway Fines Preservation process using EK35 and EnviroKleen. With this process, the runways are first prepared by grading, followed by multiple applications of EK35 and/or EnviroKleen, using a serial sprayer available from Midwest that binds and stabilizes the surface.
“Not only does this reduce gravel runway maintenance costs by 50%, but the surfaces take on a pavement-like strength, and dust is reduced by 80 to 95% for up to four years,” says Vitale. He notes that pilots and runway operators in these remote regions have been satisfied with the results. “There is minimal damage to aircraft from foreign object debris, and since there is practically no dust, this means increased passenger and aircraft safety as well.”
However, prior to the application, says Vitale, an analysis of the surface aggregate is needed, as well as consideration of climate conditions, traffic, and more to create the most appropriate solution and treatment plan.
“All of our family of synthetic fluid products are environmentally sound and safe for humans. It is extremely pure and nontoxic to the environment, as our binders include pitch resin, which is naturally occurring from trees.”
When treated, the runway has an improved surface strength and is virtually maintenance free, and dust is controlled to minimal levels.
According to the Alaska University Transportation Center, Midwest’s EK35 was selected for inclusion in studies to investigate longevity of dust control palliatives because of rural Alaska’s need to find cost-effective methods to reduce road and airfield dust.
The trailer-mounted fusion unit has its own power generator.
Being a Good Neighbor
Holland, MI, located on the eastern shore of Lake Michigan and with a current population of more 33,000, was a very different town in 1905, when Louis Padnos founded his scrapyard there. Today, more than a century later, the Padnos scrap and recycling operation is still in the same place but has grown to serve many locations across Michigan.
“The town of Holland literally grew up around us,” says company spokesperson Tim Driesenga.”Over the years the company invested in large scrap processing equipment, and it’s not something you can just up and move. However, we are sensitive to our neighbors, and we’ve made it our responsibility to manage and control the dust that is created from our operation.”
Driesenga says that the company’s Holland location, while not the biggest in volume, at 29 acres is the largest in size. Dust is generated both from the processing of scrap and from the trucks that transport the final product to steel mills and foundries. Driesenga explains how dust occurs in this industry that handles mostly metals, a product not usually thought of as dust producing.
DustBoss unit
“We have a lot of loose sheet iron from auto bodies and old appliances—washers, dryers, and so forth—all post-consumer scrap. The advantage to our processing is this all has value and it can be recycled, but the intrinsic value is landfill avoidance.”
But dust is a problem. “Scrap itself is dirty; it’s oxidized or rusty. But in the high traffic areas where we’re moving all that, we’ve solved the problem with the DustBoss from Dust Control Technology [DCT],” says Driesenga.
“People’s expectations have changed from what they were willing to accept 20 or 30 years ago, and the company has committed to being a good neighbor in the community. The town grew up around us, and we have to make sure we hold ourselves to high standards in dust control.”
DCT president Laura Stiverson explains the dust control capabilities of the line of DustBoss products. “This unit is designed to mitigate fugitive dust using an atomized mist with a water droplet comparable in size to the dust particles, so they are ‘attracted’ to each other, which then makes the particle heavy so it falls to the ground.
“The key component is a ducted fan that is engineered to create a column of air mixed with water in a fine mist. They have a lot of coverage; the largest one can shoot mist out 300 feet. The fine mist is generated by multiple nozzles. Some units have up to 30 nozzles, but we help customers determine which machine, how many nozzles, and how much mist they will need to generate to match the amount of dust they have.”
The DustBoss looks something like a large portable cement mixer and can be mounted on a truck and moved to different locations. Some can be mounted high up on pedestals with their rotation governed by a remote-control operator, who can direct the mist to where it needs to be.
“We also have a Fusion unit paired with a generator and placed on a trailer, so the power is right there,” says Stiverson.
After 10 years, the first DustBoss machines are still going strong, and Stiverson says they are now used in more than 35 countries. “Customers who have been using conventional water spraying to control dust will see significant benefits in lowered operational costs plus substantial savings in water use when switching to DustBoss. We make every effort to listen to the customer and meet their needs, and sometimes that means reinventing our own product.”
Back to the Drawing Board
This flexibility was key for the Padnos operation. Driesenga describes how the scrapyard purchased its first DustBoss, then increased the number of units. But when they asked for custom remote capabilities, “We really stretched the DustBoss people,” he says.
“We put it up, but it took too long to rotate and move. We couldn’t do everything we wanted it to do with the remote, and it was taking three minutes to do an entire 360-degree rotation. If you have guys on the ground managing and moving materials, they need it to respond quickly and go where they are. Three minutes is like an eternity. So we told the DustBoss people it takes too long and needs to go faster.”
Stiverson says her designers went back to the drawing board and customized the equipment. “We equipped it with a toggle button and a faster oscillator to cut down on the amount of time it took to reposition the barrel. This is important when trucks pull up to be loaded. When the truck is done being loaded, the operator simply hits a ‘home’ button to have the barrel return to where it had been positioned.”
Driesenga says his operations staff are much happier. “If you make it easy for employees, they will use it. It’s like safety: If it takes too long to implement a system, or it’s too cumbersome to use, people won’t use it. It’s the same thing with environmental management. Now, the pedestal-mounted DB-60 rotates a complete 360 degrees within 30 seconds. This is a real testimony to their ability to improve the product to meet our needs.”
Taking a Water-Saving Technology Up a Notch
In the Land Down Under, the annual rainfall is less than 10 inches in most places, making Australians some of the world’s leading innovators in water-efficient technologies. Rick Irwin, president of Ocala, FL-based Ecologel Solutions, says the company’s water conservation and dust control technology, GelTrak, was originally one of those innovations.
“GelTrak was developed by an Australian chemist in the early ’90s to capture surface and subsurface moisture that would otherwise be lost to evaporation. The collection of moisture keeps roadway surfaces nominally damp while coagulating dust fines to larger particles, thereby minimizing roadway dust.”
Irwin explains that although the technology was originally developed to control dust on dirt roads in the mining industry, it became better known in the United States—under the trade name Hydretain—as a product that dramatically reduces the watering requirements for all types of ornamental plants, shrubs, trees, turf, and even agricultural crops.
“First tested at the University of Florida as a method of treating ornamental plants, Hydretain proved to significantly reduce watering requirements and increase the shelf-life of plants from the nursery through the retail sales cycle,” says Irwin.
He adds that the university had never seen another water management product like it, and Ecologel began strengthening it for use within the turf industry so customers with water restrictions could cut water bills but still have a lush green lawn.
Track before treatment
The product, he explains, is composed of “food-grade materials consisting of sugar alcohols, neutral salts of alpha hydroxypropionic acids, and other hygroscopic humectants. People became very interested in this as a ‘green’ product that could get them away from calcium chloride [CaCl]-based products for dust control.”
He notes that some of the perceived negatives of CaCl for dust control include the potential effects of excessive chloride on the environment and surrounding vegetation, as well as the corrosiveness of CaCl on vehicles and equipment. “In Chile, for example, a mining operation in the mountains was using CaCl with water to control dust, but it was eating up their vehicle brake lines. By applying GelTrak, they significantly extended the time between required watering and reduced overall dust control costs. So they were not only saving the road from erosion, and saving their vehicles from corrosive damage, but also saving water and the energy and fuel needed to apply that water.”
After GelTrak application
Less Dust, Better Business
Before surfing the net in search of help to control dust on his racetrack, owner Bubba Clem says, he had been “typically watering the three-eighths-mile clay track no less than six or seven times a night before race time.”
He describes his Bubba Raceway Park of Ocala as a “clay-based surface that has been in operation for more than 62 years, attracting a variety of racing classes and hosting 11 racing series. It’s a popular place, but to keep it attractive for vehicles and competitors, proper maintenance is crucial.
“The clay surface likes water, and it’s a lot more absorbent than the average dirt track. We have to keep it moist to keep it competitive, and this keeps it friendly on tires for our competitors.”
He adds that the cars have high horsepower and the tires experience a lot of friction, which kicks up a lot of dust. That means the track is literally losing ground.
“When I was looking for a product to help keep the surface, I just started searching online and found that GelTrak was from a locally owned company called Ecologel.”
Enthusiastic over the results, Clem says, “This is the most remarkable stuff when it comes to keeping moisture in my track.
“I’ve been using GelTrak for just over a year and it doesn’t take much, only 2.5 gallons of product to 2,500 gallons of water, which is our standard watering tank. I put it on early before the hot laps around 5:30 p.m., and we do several waterings—the GelTrak goes in on the third watering and it works itself into the track. But what I’ve noticed is my surface is building up a memory to it, and it’s conditioning the soil, so now it’s taking less and less water to do the same job.”
Drivers have also noticed it’s a more race-friendly surface. “They’ve said the track has more grip and doesn’t dry out as much, so it’s not so hard on their tires.”
But the best news is that using GelTrak has made a significant dent in the track maintenance. “We used to do six or seven waterings a night, and each one is 2,500 gallons of water. So if we’re open 60 to 65 days a year, and if you do the math, each day is using 15,000 gallons, or almost a million gallons a season! But if we’re down to four or five waterings, it’s an astronomical savings, not just in water, but in diesel fuel, the electricity to pump the water from our well, and the wear and tear on the pump.”
Saving the Road, Saving Water
Analytical chemist Steve Clark brings his expertise in surface science to EnviroTech Services Inc, of Greeley, CO, which, he says, continues to improve methods and technologies that are environmentally responsible to preserve soil, conserve water, and control dust.
The company’s endeavors have been rewarded with EnviroTech dust-abatement products X-Hesion Pro, durablend, and Compact & Cap earning a place in the US Department of Agriculture’s BioPreferred catalog.
According to the USDA, the BioPreferred Program catalog is “designed to assist users in identifying products that qualify for mandatory federal purchasing, are certified through the voluntary labeling initiative, or both.”
Clark says the road maintenance program called Compact & Cap was tested at two wildlife refuge centers where dust, erosion, and road surface loss were problems. “Dust control products only work when a road surface is at least 85% compact,” he says. Compact & Cap uses X-Hesion Pro and/or durablend in a three-step process; the road is first compacted, then sealed, and then protected.
He explains that durablend is an enhanced polymer blend that bonds to aggregate but requires only half the amount of a typical magnesium chloride treatment. X-Hesion Pro is an ultra-low-chloride-based formulation for dust control that uses agriculturally derived complex organic polymers.
Road at Squaw Creek Refuge
“Durablend-C is a CaCl2-based product that is enhanced with organic polymers, and this does two things: It helps bind the road base particles and fines together and helps keep the chloride from migrating so there is less leaching. So in this three-step process we mix the product in with a couple of inches of surface with a grader or blade, then compact it, then seal the surface with the same product.”
Clark describes a dynamic road such as one leading to a landfill. “These roads are constantly changing due to the traffic and the nature of the facility’s business” and are constantly having new dirt deposited on top. When X-Hesion-Pro is applied to control dust, as a humectant it both prevents moisture from evaporating and adds stability to the road.
“One landfill used six to eight water trucks per day, started the water conservation program, and found they used less water. The landfill went from six to eight water trucks down to one, which meant 84,000 fewer gallons of water a week.”
Better Birdwatching Through Science
Bethany K. Kunz of the US Geological Survey in Columbia, MO, participated in a test of durablend-C. Her agency partnered with the US Fish and Wildlife Service to help dust-beleaguered Squaw Creek Refuge near Mound City, MO, find wildlife-friendly products. Envirotech’s durablend-C was selected as a test product.
“Squaw Creek has a 10-mile auto tour gravel loop around the refuge, which receives a lot of use from visitors who come to enjoy nature and photograph birds,” she says.
Kunz says this gravel road, which handles about 100,000 cars a year, is also adjacent to a large wetland complex, which attracts many species of waterfowl. “They have huge numbers of snow geese.”
“Almost everyone drives the loop, and we knew there was a severe dust problem. So we thought it would be a good place to put some of the different soil stabilizer products we had tested in the USGS lab out to work in a real-world situation to see if they were effective and environmentally friendly. We had tested several practically nontoxic products in the lab at USGS but wanted to see what their potential was when applied in an uncontrolled environment.”
Kunz says federal lands in general don’t have the resources or equipment to apply water on a regular basis, and the dust at the Squaw Creek Refuge creates a visibility hazard and erodes the road.
“We used durablend in the Compact & Cap program, applying this to two half-mile sections of road and then monitoring them for a almost year and a half, comparing them to an untreated control section. We used a particulate matter meter to measure dust at six points during the test.
At the end of the program Kunz says, the durablend “showed a 90% reduction in dust for the 15 months after the application” when compared to the untreated control portion of roadway.
“The refuge has been really pleased. But even though they were happy about the dust control, they were more interested in the preservation of gravel. Every dollar saved on gravel can go to better serving visitors.”
Kunz says there was concern whether any chloride would leach into soil and damage vegetation, ultimately affecting the wetlands and wildlife. “We didn’t see any damage to vegetation during the 15-month test. We also did a fairly extensive sample of roadside invertebrates that might have been affected by the product application, and saw no differences between the control and treated areas.”
Kunz notes that one reason for choosing durablend was “its combination of effectiveness of a chloride-based product with a binder designed to reduce leaching of the chlorides from the road.”
Engineering the Future
From saving water to preserving road surfaces to protecting the natural environment, today’s dust control technologies are benefitting from the latest technologies that can develop increasingly green products for dust abatement. As concern over climate change and efficient use of our natural resources increases, keeping water and soil where it should be—harmlessly—is an ever-expanding effort.
Fugitive dust is airborne particulate matter that is not identified as coming from a specific source, such as a smokestack, pipe, or other direct output. The individual particles of house dust can easily be seen swirling as dust motes in a bright sunbeam, but particles of industrial fugitive dust can form opaque white, gray, or brown billows comprising billions of tiny particles.
This particulate matter (PM) is designated a hazardous pollutant by EPA. The size and amount of allowable hazardous PMs are regulated by EPA’s National Ambient Air Quality Standards. To ensure that these standards are being met, state and local air monitoring systems routinely provide air quality information to the agency’s Aerometric Information Retrieval System.
Over time, since the first PM regulation in 1971, the permissible number and size of PMs has been modified, as recently as March 2015. Particles are defined as “coarse particles,” those with a diameter less than 10 microns, and “fine particles,” those with a diameter equal to or less than 2.5 microns.
In the world of dust particles, smaller is not better. According to EPA, it is the smaller particles that are of greatest concern, as they can be inhaled and reach the deeper regions of the lungs where they can cause serious health problems. When these particles carry heavy metals, chemicals, or other contaminants and enter air or waterways, they can be life threatening.
