March/April 2007

Stricter enforcement prompts new control measures

A clause in the Arizona Pollution Discharge Elimination System stormwater permit requires the developer or the contractor filing a permit to stabilize any lot or stockpile that will not be used for 14 days, says Tracy Castell, a Tucson, AZ, branch manager for WindSwept Organix.

WindSwept Organix uses TERRALOC as temporary soil stabilization. The soil-penetrant dust palliative is a solution of polyvinyl alcohol and additives used for loose and dry or slightly damp surfaces. 

"We like using the TERRALOC because it is much easier to clean up our equipment, and it is easier to use and more installer friendly," Castell says. 

Castell has applied the substance on the surface with both a water truck and a hydroseeding machine, depending on the terrain and the job, and sometimes will switch between the two on one job.  He uses an application of 132 gallons of TERRALOC per acre, which he says is a light application, used particularly for the 14-day rule. 

"Typically, we do it to meet the intent of the permit and won’t do a reapplication unless the inspector requires the developer to do so,"   Castell says.

As for dust control, Castell notes that just as in Maricopa County, the county in which he operates—Pima County—is starting to crack down just as strictly on violations.

Techniques for desert campsites, country roads, vineyards

Saddling Up, Keeping Dust Down

For the past 51 years, a group of people have met once a year in Wilcox, AZ to take part in an old historic trail ride called Los Charros del Desierto, or "Horsemen of the Desert." The group camps out, rides during the day, and returns in the evening, explains Martin Bowen, vice president and chief financial officer of Fine Line, based in Fort Worth, TX, who takes part in the event.

"We have had a problem [with dust] in the past. We have a campsite of 4 or 5 acres. The road was just dirt. On the road you have 150 riders. In and out, you probably had on the road maybe 75 to 100 trucks and SUVs pulling trailers," says Bowen, noting visitors may spend three or four days at the site. This year, TERRALOC was applied to the area.

In the arid climate, heavy dust can irritate the corners of a rider’s eyes or his or her nose during the event.

"We did it because we thought it would help with the people riding on the roadways," says Bowen. "Apparently, the most important thing was keeping the pollen down and keeping the dirt out of the food. It worked very well. You don’t even know it’s there."

The dilution rate of the biodegradable dust control product was altered to suit the treatment site. "Normally a typical dilution rate is one part TERRALOC to three parts water.  "In this application, it was one part TERRALOC and nine parts water. We had no product on the vegetation. This produced an effect that percolated inside the soil without residues on the substrate.”

The product was mixed in a water truck, explains Bowen, and applied a few days prior to Los Charros del Desierto. The effect the product had on pollen was noticeable, according to Bowen.

"A doctor came up to me after a couple of days," notes Bowen. "He said this really held the pollen count down."

People who cooked the riders’ food were also pleased with the dust control that was applied in the high desert, where the terrain consists of grasses, cactus, and rocky, rough ground, says Bowen. "It kept the dust out of the food," he notes, commenting on the wind in the area. "They were cooking on open flames out in the desert."