Removing the toughest pollutants
In the past five years, designs that are much better at picking up 250-micron-and-smaller particles have entered the market. The latest testing indicates that the pickup efficiency of regenerative air and vacuum sweepers is 80% to 90%.
A 2011 article by internationally recognized expert Roger Sutherland of Amec Foster Wheeler explains how technology changes since NURP have improved small-particle pick-up ability. “Real-World Street Cleaner Pickup Performance Testing” includes a chart with the historical NURP baseline results and 2011-to-current data.
Other studies by Sutherland indicate that today’s mechanical broom sweepers reduce TSS for $7 to $13 per pound.
In addition to maximizing small-micron pickup, minimizing fugitive dust output is the best way to lower runoff pollution. Because they rely on air technology to entrain small particles and can be outfitted with a better system to entrain fugitive dust, regenerative air and vacuum sweepers reduce TSS for $3 to $7 per pound.
Similarly outfitted mechanical broom sweepers are generally the most expensive in terms of initial purchase price, followed by vacuum models and then regenerative air models, although chassis and the degree to which the sweeper is equipped with options and accessories all significantly impact final cost. Recent increasing overall costs for sweepers have been largely driven by the EPA-mandated move to Tier 4 engines.
Next page: Test driving a sweeper