Power sweeping has been shown to be the most cost-effective initial BMP for reducing pavement-based storm water runoff pollution from the nation’s waterways and also helps keep small particulate pollution from the air. For city managers, the questions should be three-fold: 1) how often should we sweep to maximize pollutant removal before moving to other methods; 2) what type of sweepers should be used in our differing geographical locations; and, 3) should we perform our own sweeping in-house or contract the service to a private sweeping contractor?
In my 30+ years of writing about the power sweeping industry, all of the above have been the subject of articles and research. We now know that in all cases, requiring vehicle removal during sweeping is the way to achieve the best environmental and cosmetic benefits. An optimal sweeping frequency can be determined through testing the pollutants in your area’s street dirt, along with measuring the amount of material removed by sweepers during differing frequencies of sweep.
We also know that regenerative air and vacuum sweepers will, in general usage, pick up more small "fines’"— where pollutants tend to congregate — than will sweepers offering only a mechanical broom pickup system. However, air-based sweepers can’t handle large objects like tire casings, mufflers and boxes, so they are not feasible for roadways where that type of material tends to collect.
Finally, on the topic of privatization vs. in-house: Contractors specializing in street sweeping, many of whom are members of the World Sweeping Association, will likely be able to provide professional input about sweeping frequency as well as the type of sweepers to use in different situations. Most will also have a diverse fleet of sweepers, which allows them to match the right type of sweeper to a city’s particular needs.
Because sweepers are uniquely difficult to keep in good operating condition, specialized sweeping contractors also tend to be more able to maintain their sweepers so they operate at a level close to original specifications.
Finally, whether you’re a contractor or work for a municipality, if you want to get a better handle on what your sweeping program currently costs you send an email to [email protected]. We will provide you with a worksheet we developed to assist in determining your street sweeping cost per hour or per curb mile.