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December 2007

Automated dust control useful at Minnesota transfer station

Automated misting systems prove effective in settling airborne dust in waste facilities.

A Minnesota waste transfer station has obtained excellent control of airborne dust particles, while reducing costs for manpower, fuel and replacement air filters on heavy equipment through high-efficiency automated dust control. The new dust suppression system has been so effective that company officials expect the payback period will be less than 12 months.

Like many transfer stations and recycling facilities, the Resource Recovery Technologies staff at the Malcolm Avenue transfer station in Minneapolis had been battling airborne dust by manually spraying with a fire hose. The facility typically receives 250 truckloads of residential refuse, yard debris and wood scraps each day, processing about 450 tons of debris, operating five days a week.

“We found several disadvantages to manual spraying for dust control,” commented site supervisor Ken Tritz. “The technique was only marginally successful in knocking down the airborne particles, leaving us with a visible dust cloud virtually all day. As a result, the air filters on our heavy equipment needed frequent replacement, which drove up operating costs.”

That approach saturated the debris piles, which became a major issue according to Tritz. “The oversaturated material was far heavier as a result of the constant spraying,” he said. “That meant we were using more fuel in trucks hauling to the landfill, essentially paying extra to transport the water weight in each load. When we looked at the increased costs, the added manpower required and the potential for slipping on floors with standing water, we knew we needed a better solution.”

While researching the available alternatives to manual spraying, Tritz came across some information on a fully automatic high-pressure misting system designed specifically for dust control. He learned that the oscillating fan from Dust Control Technology (DCT) located in Peoria, Illinois, is built to atomize droplets to the optimum size for dust suppression, 50-200 microns, and decided to give the unit a try.

“After just a few days, we noticed a dramatic improvement in the air quality,” observed Tritz. “Visibility was greatly improved, and we no longer needed to waste manpower by having a worker spraying a fire hose over the material all day.”

The Dust Boss DB-30 requires only 15 PSI of constant pressure, and water is supplied by a standard 5/8”″ garden hose. “This unit is designed from the ground up for effective dust suppression,” said DCT president Edwin Peterson.

Between the manpower savings, reduced fuel costs and longer air filter life, Tritz estimated that the payback on the unit would be less than a year.

“We were spending four to six man hours each day, trying to control the dust manually,” he continued. “Now we’ve eliminated that wasted effort, and we’ve significantly reduced the time required to constantly inspect and change air filters on our wheel loader and other heavy equipment. It’s also created a better work environment and contributed to improved employee morale.”

Resource Recovery Technologies (RRT) operates 13 facilities across Minnesota, providing sustainable and cost-effective disposal and recycling for a variety of materials, including construction and demolition debris, municipal solid waste, yard waste, wood waste and source-separated organic material. The company is the largest processor of organic materials in the Midwest, and in 2005, RRT facilities processed over 250,000 tons of construction and demolition debris, 500,000 tons of municipal solid waste and over one million cubic yards of yard debris and wood waste into fuel for electricity generation, soil amendments and mulch products.