Cleaning Up Our Streets
Street sweepers not only pick up trash and wash our roads, but they also pick up dirt, motor oil, car chemicals, spilled gasoline, and other contaminates before they are likely washed down storm drains and into the environment. Street sweepers collect all this so it can be disposed of in an environmentally friendly way, and keep contaminants less likely ending up in rivers and lakes.
History of Street Sweepers
In the old days, cities would employee a group of street sweepers with wide bristle brooms to sweep through the streets. Today the job is done so much more efficiently with those large, slow-moving trucks. But the leap between push brooms to the automated trucks you see prodding along streets is filled with interesting developments.
Mechanical moving street sweepers predate Henry Ford and the first automobiles. The Industrial Revolution was filled with clever innovations for their times. There is debate as to if the first mechanical street sweeper was invented in 1849 by C.S. Brooks or if it was C.B. Brooks in 1896. (C.B. Brooks, incidentally, invented the paper hole punch.) These street sweepers were pulled by horses.
Elgin from Illinois began mass producing mechanical street sweepers and in 1914 the city of Boise, Id. purchased the company’s first street sweeper machine. These were loud, cumbersome machines. Today you see the much quieter, energy efficient street sweepers cleaning paved surfaces from city streets to airport parking lots. In San Francisco street sweepers are quiet, clean machines some even using alternative fuels.
How They Work
Street sweepers clean with air and brushes. In both cases, high-pressure jets spray water to help loosen materials. The water also helps keep dust under control. The street sweepers blow or scrub dirt and debris from the road surface with a large cylinder brush. The brushes spin on average at 4,000 revolutions per minute. Other street sweepers have a large vacuum that sucks dirt and debris into a bin which is emptied after the route.
The trucks move so slow because it takes time to loosen and lift dirt and debris. The most common street sweepers are those we see in neighborhoods or parking lots. But there are also towable street sweeper machines. For smaller jobs, miniature street sweeper run on three-wheels. Some street sweepers are designed for specific jobs such as the Elgin GRV which removes de-icing solution from airport runways to stop it from seeping into groundwater.
For a city such as San Francisco street sweepers cost the city around $100,000. A vacuum model costs around $150,000 and a street sweeper that runs on alternative fuel engines costs around $200,000.