Streets, roads, highways and parking lots accumulate significant amounts of
pollutants that contribute to stormwater pollutant runoff to surface waters.
Pollutants, including sediment, debris, trash, road salt, and trace metals
can be minimized by street sweeping. Street sweeping can also improve the
aesthetics of municipal roadways, control dust and decrease the accumulation
of pollutants in catch basins. An effective municipal street sweeping
program can meet regulatory requirements, assess street sweeping
effectiveness, and minimize pollutants in roadways.
Municipalities can choose between the three different types of street
sweepers (mechanical, regenerative air and vacuum filter) keeping in mind
the targeted pollutants, pollutant type (large debris to particles less than
10 microns in diameter (PM10)), types of surfaces, travel distances, noise
ordnances, and costs. Municipals often find it useful to have a compliment
of each type of street sweeper in their fleet (CASQA, 2003).
Each type of street sweeper has it advantages and disadvantages concerning
pollutant removal effectiveness, traveling speed, and noise generated by the
street sweeper. With the different types of modern street sweepers capable
of removing PM10 particles, price and personal preference are the primary
selection criteria for most users (Keating, no date). No definitive
independent studies have yet been staged to determine "the best" sweeping
system. Anecdotal data has also been inconclusive (Keating, no date).
Street sweeping is practiced in most urban areas, often as an aesthetic
practice to remove trash, sediment buildup, and large debris from curb
gutters (RIPDES, no date). Effective street sweeping programs can remove
several tons of debris a year from city streets minimizing pollutants in
stormwater runoff. In colder climates, street sweeping can be used during
the spring snowmelt to reduce pollutants in stormwater runoff from road
salt, sand and grit.
An effective municipal street sweeping program should address at a minimum
the following components:
Street Sweeping Schedule: Designing and maintaining a street
sweeping schedule can increase the efficiency of a program. A successful
program will need to be flexible to accommodate climate conditions and areas
of concern. Areas of concern should be based on traffic volume, land use,
field observations of sediment and trash accumulation and proximity to
surface waters (CASQA, 2003). Street sweeping in these areas may need to be
increased and the schedule amended. It is recommended that schedules
include minimum street sweeping frequencies of at least once a year. In cold
climates prone to snowfall the Connecticut Department of Environmental
Protection recommends that municipalities conduct street sweeping as soon as
possible after the snow melts (McCarthy, 2005). Removal of the accumulated
sand, grit, and debris from roads after the snow melts reduces the amount of
pollutants entering surface waters.
To evaluate the effectiveness of a street sweeping program, municipalities
should maintain accurate logs of the number of curb-miles swept and the
amount of waste collected (CASQA, 2003). Monthly or yearly intakes (per ton)
can be measured per district, road, season, or mile. This information can be
used to develop a written plan, schedule, and periodic re-evaluation for
street sweeping that would target the following:
- those roadways with contributing land uses (high level of
imperviousness, high level of industrial activity) that would be expected to
show high pollutant concentrations and
- those roadways that have consistently accumulated proportionately
greater amounts of materials (pounds per mile swept) between currently
scheduled sweeps (Curtis, 2002).
Gross intake amounts can be presented to regulatory agencies and to finance
directors to measure performance. The City of Dana Point, California
reported that when sweeping was conducted twice a month, the monthly debris
intake was 23 tons. Dana Point then increased street sweeping frequency to a
weekly basis and the monthly total increased to between 45 and 80 tons of debris (City of
Dana Point, 2011).
Street Sweepings Storage and Disposal: Street sweeping material
often includes sand, salt, leaves, and debris removed from roads. Often the
collected sweepings contain pollutants and must be tested prior to disposal
to determine if the material is hazardous. Municipals should adhere to all
federal and state regulations that apply to the disposal and reuse of
Municipalities are encouraged to develop comprehensive management plans
for the handling of sweepings. A critical aspect of a management plan is
selecting a location for storing and processing street sweepings (McCarthy,
2005). Storage locations should be equipped with secondary containment and
possibly overhead coverage to prevent stormwater runoff from contacting the
piles of sweepings. It is also recommended to cover the piles of sweepings
with tarps to prevent the generation of excessive dust. Storage locations
should be sized accordingly to completely contain the volume of the disposed
sweepings. To estimate the size of the storage location, estimate the volume
of sweepings either on a ton-per-street mile or on pounds-per-capita basis
(McCarthy, 2005). An average figure for urban areas is 20.25 tons-per
street-mile (McCarthy, 2005).
Street Sweepings Reuse Practices: Although sweepings may contain
pollutants, federal and state regulations may allow the reuse of sweepings
for general fill, parks, road shoulders and other applications as long as
the material is not a threat to surface waters. Prior to reuse, trash,
leaves, and other debris from sweepings should be removed by screening or
other methods (MPCA, 1997). Trash and debris removed should be disposed of
by recycling or sent to a landfill (MPCA, 1997).
Parking Policy: Established parking policies increases the
effectiveness of a street sweeping program. Parking policies can be
established as city ordinance and incorporate the following:
- Institute a parking policy to restrict parking in problematic areas
during periods of street sweeping.
- Post permanent street sweeping signs in problematic areas; use temporary
signs if installation of permanent signs is not possible.
- Develop and distribute flyers notifying residents of street sweeping
schedules (CASQA, 2003).
Operation and Maintenance Program: A municipality should dedicate
time for daily and weekly equipment maintenance. Regular maintenance and
daily start up inspections insures that street sweepers are kept in good
working condition (City of Greeley, 1998). It is vital for municipals to
inventory and properly stock parts to prevent downtime and decrease
productivity. Old sweepers should be replaced with new technologically-
advanced sweepers, preferably modern sweepers that maximize pollutant
removal (CASQA, 2003).
Limitations and Cost Considerations
Street sweeping programs are limited by costs. The largest expenditures
include staffing and equipment (CASQA, 2003). The capital cost for a
conventional street sweeper is between $60,000 and $120,000 with newer
technologies approaching $180,000 (CASQA, 2003). Street sweepers have an
average life span of 4 years yet more modern street sweepers have been
reported to surpass the 4 year average, therefore programs must budget for
equipment replacement. The following table shows cost estimates compared to
equipment life span and operation and maintenance for two types of sweepers:
mechanical and vacuum.
Table 1. Estimated costs for two types of street sweepers
O&M Cost ($/curb
Cost data for two cities in Michigan provide some guidance on the overall
cost of a street cleaning program. Table 2 contains a review of the labor,
equipment, and material costs for street cleaning for the year 1995
(Ferguson et al., 1997). The average cost for street cleaning was $68/curb
mile and approximately 11 curb miles/day were swept.
Table 2. The cost of street cleaning for two cities in Michigan
Street sweeping can be an effective measure in reducing pollutants in
stormwater runoff. During the year 2000, the Department of Highway Services
and Bethesda Urban Partnership in Montgomery County, Maryland swept
approximately 14,373 miles of roadways and removed 2,464 tons of materials
(Curtis, 2002). Decreasing the amount of pollutants in roads before they are
picked up by stormwater runoff reduces pollutants in surface waters.
Using modern efficient street sweepers may reduce the need for other
structural stormwater controls. Municipal stormwater managers should compare
potential benefits and costs of street sweeping. Street sweeping may prove
to be more cost-effective than certain structural controls, especially in
more urbanized areas with greater areas of pavement (SMRC, Rhode
California Stormwater Quality Association (CASQA). 2003. Best
Management Practices (BMP) Handbook, Municipal.
[http://www.cabmphandbooks.com/Documents/Municipal/SC-70.pdf [PDF - 132 KB - 9 pp] ]. Accessed May
Caraco, D. and R. Claytor. 1997. Stormwater BMP Design Supplement for
Cold Climates. Center for Watershed Protection, Ellicott City, MD.
City of Dana Point, California. Street Sweeping. [http://www.danapoint.org/index.aspx?page=343 ]. Accessed November 28,
City of Greeley, Colorado. 1998. Street Sweeping Plan.
Curtis, M. 2002. Street Sweeping for Pollutant Removal. Department
of Environmental Protection, Montgomery County Maryland.
Ferguson et.al. 1997. Cost Estimating Guidelines: Best Management
Practices and Engineered Controls. Rouge River National Wet Weather
Demonstration Project, Wayne County, MI.
Finley, S. 1996. Sweeping Works. Pavement Maintenance and
Reconstruction. October/November. pp. 16 and 17.
Keating, Janis. No date. Street Sweeper, Picking up Speed and Quieting
w_0207_street.html ]. Accessed May 4,
McCarthy, G. 2005. Connecticut Department of Environmental Protection.
Guidelines for Municipal Management Practices for Street Sweepings and
Catch Basin Cleanings.
Minnesota Pollution Control Agency (MPCA).1997. Managing Street
RIPDES Storm Water Program Guidance Page. No date. Pollution
Prevention: Parking Lot and Street Cleaning.
[http://www.dem.ri.gov/programs/benviron/water/permits/ripdes/stwater/t4guide/fact10a.htm ] Accessed May 3,
Satterfield, C. 1996. Enviro Whirl 1 PM-10 Efficiency Study Removing
Reentrained Road Dust. June Lake, CA.
SWRPC. 1991. Costs of Urban Nonpoint Source Water Pollution Control
Measures. Southeastern Wisconsin Regional Planning Commission. Waukesha,