A continuous filtration system prevents very fine particulate matter from leaving the hopper, which prevents the formation of the dust trails typically seen with conventional mechanical sweepers. A specialized rotating brush is used to scratch and loosen dirt and dust from impervious surfaces, allowing the vacuum system to recover practically all particulate matter. The mechanical sweeping component in these sweepers is completely dry. The technology has also been applied to industrial sites where complete removal without leakage of particulate matter is important. These sweepers apply technology originally developed to remove spilled coal and coal dust from railroad tracks.

Vacuum-assisted dry sweepers combine the important elements of tandem sweeping into a single unit. If the accumulated loading is not too great, regenerative air sweepers are generally considered effective for removing fine sediment (Sutherland and Jelen, 1996). Air is regenerated for blowing through a dust separation system. Regenerative air sweepers blow air onto the pavement and immediately vacuum it back to entrain and capture accumulated sediments. Tandem sweeping operations involve two successive cleaning passes, first by a mechanical (broom and conveyor belt) sweeper, followed immediately by a vacuum-assisted sweeper. The overall efficiency of vacuum-assisted cleaners is generally higher than that of mechanical cleaners, especially for particles larger than the dust and dirt range (larger than about 3 mm). The transported dirt is usually saturated with water. However, the refuse is then placed in the path of a vacuum intake that transports the dirt to the hopper. Vacuum-assisted sweepers also use gutter brooms to remove particles from the street. This is the most widely used equipment for street cleaning in the United States. The particles removed are placed in the path of a cylindrical broom that rotates to carry the material onto a conveyor belt and into a storage hopper. Mechanical sweepers employ a rotating gutter broom to remove particles from the street gutter area, with a water spray used to control dust. Streetsweeping is not effective in removing oil and grease, and older conventional mechanical sweepers are limited in their ability to remove fine sediment. The benefits of streetsweeping will be best realized by using the most sophisticated sweepers at a weekly to bimonthly frequency depending on local conditions, with a careful assessment of whether certain rules such as restricted street parking prior to and during sweeping can be enforced. For highway applications, streetsweeping may be considered for road shoulders, where safety permits, rest stop parking areas, or maintenance yards. It should be considered in commercial business districts, industrial sites, and intensely developed areas in close proximity to receiving waters. Streetsweeping is well suited to ultra-urban environments where little land is available for installation of structural controls. Recent studies have found that streetsweeping programs using equipment based on new technologies can significantly reduce pollutant washoff from urban streets, with potential reductions of up to 80 percent in annual total suspended solids and associated pollutants (Sutherland and Jelen, 1996). Streetsweeping is an effective ultra-urban best management practice for reducing total suspended solids and associated pollutant washoff from urban streets. Stormwater Best Management Practices in an Ultra-Urban Setting: Selection and Monitoring Fact Sheet - Street Sweepers

Street sweeper broom hours