Jan. 16, 2012 04:27

Death...Taxes...& Dust

When the phone rings in Chris Carroll's office at PM10 Inc., in Palm Desert, California, someone typically has a dust control problem and needs help, fast.

"We get called in for sand that's swirling off slopes and ridges. We get called for dust clouds rising at construction projects. And we get calls for haul roads where every passing vehicle sends up a cloud of dust," Carroll reports. "Every job is different, and every job requires both the right dust control product and the right operator to apply it."  Founding Father and inventor Benjamin Franklin said, "Nothing in life is certain but death and taxes."

Franklin was a genius, but he was not in the construction, mining, or transportation business. If he had been, he might have said that nothing is certain but death, taxes, and dust. He might even have added "dust enforcement" to his famous list. Not only does the Environmental Protection Agency regulate airborne dust, counties and cities are getting into the act. In several Arizona counties, you must file an abatement plan even if you're a do-it-yourselfer putting in a garage.

As a practical matter, enforcement focuses on industries that create visible dust. Jay Morris, who runs the minor source compliance section of the Utah Department of Air Quality, says the aggregate and construction industries are frequent targets.

"We get a lot of calls from the construction industry," Carroll reports. "Recently, we were engaged by John Laing Homes. The company was developing a 40-acre parcel in La Quinta, California. There was a huge high ridge abutting the development area that needed to be stabilized. The soil composition was a mix of silt and sand."

Carroll stabilized that ridge by spraying it with a polymer-based dust abatement product.

Polymers are just one of the many products from which you can choose if your business spells D-U-S-T. Environmental consultant Richard Countess, of Countess Environmental in Westlake Village, California, sets out the pros and cons of the various options in a book-length report he prepared for the Western Governors Association. (If you're feeling particularly hardcore, go to Google, search "WRAP Dust Control Handbook," and download the PDF).

Countess starts with the simplest solution: plain water. He says that water is good for knocking dust down, but not so great for keeping it down. Once the water evaporates, the dust is still there. If you run a quarry or a gravel pit, though, spraying water continuously as dust-raising is underway may be an inexpensive and functional option.

Then there are dust abatement products based on some kind of salty brine, like magnesium chloride or calcium chloride. They're typically spread atop unpaved roads. Chat Cowherd, principal advisor at MRIGlobal, based in Kansas City, Missouri, and a member of the public/private partnership Dustbusters Research Group, says such roads are the biggest class of dust generators.

"People think that smokestacks are a big source of particulates," Cowherd explains. "But smokestacks actually produce fewer airborne particles than do unpaved roads. They dry out, they rut, and every passing vehicle makes the dust fly. If there's truck traffic on these roads, watch out. Heavy trucksWhen the phone rings in Chris Carroll's office at PM10 Inc., in Palm Desert, California, someone typically has a dust control problem and needs help, fast.

"We get called in for sand that's swirling off slopes and ridges. We get called for dust clouds rising at construction projects. And we get calls for haul roads where every passing vehicle sends up a cloud of dust," Carroll reports. "Every job is different, and every job requires both the right dust control product and the right operator to apply it."  Founding Father and inventor Benjamin Franklin said, "Nothing in life is certain but death and taxes."

Franklin was a genius, but he was not in the construction, mining, or transportation business. If he had been, he might have said that nothing is certain but death, taxes, and dust. He might even have added "dust enforcement" to his famous list. Not only does the Environmental Protection Agency regulate airborne dust, counties and cities are getting into the act. In several Arizona counties, you must file an abatement plan even if you're a do-it-yourselfer putting in a garage.

As a practical matter, enforcement focuses on industries that create visible dust. Jay Morris, who runs the minor source compliance section of the Utah Department of Air Quality, says the aggregate and construction industries are frequent targets.

"We get a lot of calls from the construction industry," Carroll reports. "Recently, we were engaged by John Laing Homes. The company was developing a 40-acre parcel in La Quinta, California. There was a huge high ridge abutting the development area that needed to be stabilized. The soil composition was a mix of silt and sand."

Carroll stabilized that ridge by spraying it with a polymer-based dust abatement product.

Polymers are just one of the many products from which you can choose if your business spells D-U-S-T. Environmental consultant Richard Countess, of Countess Environmental in Westlake Village, California, sets out the pros and cons of the various options in a book-length report he prepared for the Western Governors Association. (If you're feeling particularly hardcore, go to Google, search "WRAP Dust Control Handbook," and download the PDF).

Countess starts with the simplest solution: plain water. He says that water is good for knocking dust down, but not so great for keeping it down. Once the water evaporates, the dust is still there. If you run a quarry or a gravel pit, though, spraying water continuously as dust-raising is underway may be an inexpensive and functional option.

Then there are dust abatement products based on some kind of salty brine, like magnesium chloride or calcium chloride. They're typically spread atop unpaved roads. Chat Cowherd, principal advisor at MRIGlobal, based in Kansas City, Missouri, and a member of the public/private partnership Dustbusters Research Group, says such roads are the biggest class of dust generators.

"People think that smokestacks are a big source of particulates," Cowherd explains. "But smokestacks actually produce fewer airborne particles than do unpaved roads. They dry out, they rut, and every passing vehicle makes the dust fly. If there's truck traffic on these roads, watch out. Heavy trucks make it even worse.”

Brine dust control products function by drawing moisture both from the atmosphere and from the road surface, which keeps the road surface damp. Dampness tamps down dust. Brines work well, especially on relatively flat roads that have a gravel-and-fine-material mix, but they must be reapplied in cases of significant road traffic. Rain, too, can force a reapplication. Briny runoff can be a problem, particularly with long-term use. In addition, brine is corrosive. We all know what roadway rock salt can do to a truck’s undercarriage, which is why many modern brine-based dust stabilizers contain anti-corrosives. On hilly roads, brine products may hold less effectively.

Even with these drawbacks, products utilizing brine are a time-honored and effective choice. Caution: state and local regulations may bar use in areas of low humidity. If there’s no moisture in the atmosphere, there won’t be moisture that the brine can draw to keep the road surface damp, so always check.

Next are the organic petroleum products, based on oil. In the olden days, oiling a dusty road was an accepted solution. Now, it’s a less popular choice. The problem is runoff. Petroleum is a serious pollutant, so much so that petroleum-based dust suppressants are illegal in some locations. Wisconsin doesn’t permit their use at construction sites. Minnesota bars them from gravel roads. Again, always check.

There are other organic solutions available, both plant-based and biodegradable. The lingonsulfonates, widely called lignin, are natural polymers found in wood. When applied in a mix with water, it suppresses dust by binding small particles together. Under the heat of the sun, lignin cures to impressive hardness. Organic lignin-based dust stabilizers, sugar beet extracts, and other products like them are effective on feedlots and in construction areas. Water, however, is its enemy.

The most interesting new products are manufactured polymer acrylics and acetates, which—depending on the concentration when they’re applied—form anything from a thin crust to a rock-hard, unbreakable surface. Polymers have been battlefield-tested in dusty Iraq, where soldiers using an Environmental Products & Applications, Inc. polymer gave it the loving nickname “Rhino-Snot,” after using it to fashion a helipad in the Iraqi desert. Applied in several layers on a graded site of mixed sand and gravel, it hardened practically to concrete.

All polymers, however, are not created equal. Carroll warns that the level of active polymer ingredient can vary from manufacturer to manufacturer, the same way that the amount of active ingredient in medications can vary, even though the pill size is the same. “Many manufacturers won’t put the polymer-to-stabilizer ratio on the container label,” Carroll warns. “You need to ask. Our own products have a very high percentage of active polymers.”

When the FedEx building was being constructed in Devore, California, Carroll used a polymer stabilizer on a 1,000-foot long, 20-foot high slope. “The idea was to stabilize the slope—the soil was a mix of sand and clay—so that dust wouldn’t blow during the project, without making the crust so thick that landscaping afterward would be affected.”

Don Taylor, longtime owner of Houston, Texas-based Poulenger, Inc., fashions different polymerbased dust stabilizers for different industries. “The needs of someone in the cement industry are a little different from someone in the agricultural business,” he declares. “We have five different formulations of our core product, which was originally developed to stabilize fine dust at old nuclear facilities.”

Taylor has focused attention on agriculture of late, particularly because widespread drought conditions have made between-the-crop-rows-dust more of an issue. He now has a polymer-based product specifically for farming. “You might think it’s just dirt there,” he says. “But there’s fertilizer and insecticides that settle atop the dirt, and you don’t want those things blowing around and being inhaled.”

Most recently, manufacturers have been mixing dust stabilization technologies. Jeff Collins, dust control product manager for Envirotech Services, Inc., in Greeley, Colorado, now offers a stabilizer that’s a combination polymer and brine. Suitable for unpaved roads, Collins reports that the addition of the polymer keeps the product in the road longer, while reducing briny runoff. The polymer-to-brine ratio can be specifically tailored in the Envirotech lab for a particular roadbed or roadbeds; Envirotech asks customers to provide a soil sample.

It’s not just the product you’re putting down, though. It’s how that product is being applied. Carroll talks about a dust control project he did on a set of mountainous haul roads leading to a water pumping station. “These roads were extremely steep, and it was too dry for brine. You couldn’t just flood the road with a water/polymer mix, because the liquid would just slide down and pool up in the flats.”

Carroll ended up scarifying the road, adding polymer, compacting the roadway surface, and then coating the surface again. “The wrong product applied perfectly or the right product applied poorly,” he says, “both mean the same thing. That is, the job needs to be done over again, which is costly to the customer.”

Even with all the technical advances, dust control is—like death and taxes—subject to forces beyond our control.

Don Gabrielson, director of the Pinal County Air Quality Control

District in Florence, Arizona, relates a story that he heard at a conference in the midst of the real estate boom.

“There was this local real estate guy doing a major residential development, 640 acres out in the desert. He sprayed a polymer-based stabilizer on all 640 forty acres. It worked like a charm; a thin crust settled the powdery desert sand. The guy was ecstatic.”

Then Gabrielson laughs ruefully.

“The problem was, a huge wind came through the area a few days later. It blew and blew. When the windstorm was over, the developer had an inch of silt sitting atop of his crust. It was like he’d never done the job at all.”

That’s a heartbreaking situation.

You take reasonable steps to control the dust, and you’re whipped by the elements. It seems like your only option is to grit your teeth and reapply the stabilizer.

Or is it? Is there a way to do an end-run around the problem? Or set some kind of a pick?

Cowherd and Countess brainstormed a different kind of solution to the problem of blowing dust—a solution that’s cheap, green, and innovative.

Wood chip berms

Under the auspices of the Dustbusters Research Group, Cowherd and Countess experimented with barriers that could both settle incoming dust and prevent it from being blown onto a neighbor’s property.

“We tried various kinds of fencing, but there was always dust pass-through. Then we hit on the idea of six-foot-high berms. We get free wood chips from tree trimmers, utility companies, and the government. Most of the time, they’d be headed for the landfill.”

Once wood chips are at your site, you use a tractor to build a berm at a right angle to expected strong winds. You might well want two berms. One knocks down oncoming dust, the other stops the dust from blowing onto neighboring property.

In both cases, sand and dust accumulate at the berm base. When it reaches half the height of the berm, you use the tractor to rearrange the chips for better blockage.

“They’re not right for roadways, where I still like the magnesium chloride products,” Cowherd concedes. “But we looked at the stabilizers—let’s face it, even with the polymers, when your crust gets any kind of crack, you’re heading for reapplication—and knew we had to find an alternative. Properly maintained, a wood chip berm can do the job for years. It’s green as can be, it’s biodegradable, and—best of all, maybe—it’s very cheap.”

With creative solutions like the wood chip berm, and the right dust control products applied in the right way, you can do enough to keep blowing sand, silt, and dust under control, and inspectors at bay . . . even if dust is as certain as death and taxes.

Also in Soil Erosion News


In many ways, we are fortunate that, in our chosen profession, we are able to help people when certain disasters occur: the tornadoes in Missouri, Oklahoma, Louisiana and Georgia, the flooding in Louisiana, the snows in the northeastern part of the country, the rain in California, and the snow in Colorado....

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