Tudor Van Hampton
For Don Ahern, who owns the largest independent rental chain in North America, keeping his fleet of machines looking clean and green is a daily part of the family business. But the grungy process of powerwashing construction equipment, such as dozers that can collect as much as 500 lb of dirt while working in the field, is not always friendly to shop workers and local wastewater treatment systems.
“I’ve been playing with this my entire life,” says the president of Las Vegas-based Ahern Rentals Inc. He is developing his own self-cleaning powerwashing system for Ahern’s rental yards, and he plans to sell the units to other fleet owners later this year. “You wash it like a dish,” explains Ahern, who also is tinkering with a fully-automatic wash bay.
Ahern’s equipment “dishwasher” is scalable, meaning it can be made to handle a small loader or giant motor scraper, and it is semi-portable. He starts with a rectangular box made of I-beams and plate steel. It has two chain-drive axles inside at either end that pull a conveyor of angle irons with bolt-on wear pads. They slowly drag along the bottom of the tub to bring sludge to an auger that pumps it out into a wheelbarrow or 50-lb sacks. The average cost to buy the machine is$100,000.
The “voodoo” of the process, as Ahern calls it, is an electrocoagulation treatment plant that handles about 5 gallons of water per minute. It removes the solids in the waste stream without mechanical filtration. As the dirty water passes over aluminum plates, they electrically charge suspended solids such as dirt and grease, which fall to the bottom. Metals also are oxidized, so the remaining sludge can be tossed out with the garbage. “EPA loves that,” says Mike Davis, an applications engineer with OilTrap Environmental Products Inc., which makes the electrolysis unit. The leftover recycled water is clean enough to go back through a pressure washer without damaging the pump and spray head.
Tudor Van Hampton
Separation tanks are the heart of Ahern’s equipment “dishwasher” (above).
Environmental pressures to reuse water and keep local sewer lines clean is forcing fleet owners like Ahern to be creative with their washing practices. “We’re growing about 50% a year, and it’s hard to keep up,” says Dale Nelson, president of Tumwater, Wash.-based OilTrap. Like Ahern, it also helps people design washers, such as container-sized units that can ship anywhere. Customers include Ritchie Bros. Auctioneers, NES Rentals, Caterpillar Inc. and Halliburton, it claims. Lumber suppliers use it to reuse water in pressure treatment, as do metal manufacturers.
Nelson, a former IBM engineer, says that the secret to the electrocoagulation process is an internal computer program that automatically monitors the treatment, making it easy for shop workers to use.
Cleaning equipment does not have to be a dirty job anymore, adds Ahern. “If you unload it off the truck onto the washer, you don’t have to pay someone to sweep,” he says.