Operational Tips for Sweeping Professionals
10 Tips for Ensuring a More Environmental and Cost-Effective Street Sweeping Program
by Roger Sutherland, President of Cascade Water Resources and Principal Engineer in the worldwide engineering firm, Wood. PLC.; and, Ranger Kidwell-Ross, Editor, WorldSweeper.com and Director of the World Sweeping Association.
Our editor asked Roger Sutherland, arguably the world's top expert on street sweeper testing, to provide five ideas for what a sweeping program might do to increase its effectiveness.
Sutherland took it one step further: He offered five ideas that could be immediately implemented into a sweeping program, then added another five that should be strongly considered.
Kidwell-Ross then expanded upon Sutherland's 10 items and they went back and forth from there. The result is a "must read" article for everyone involved in sweeping streets. Whether you are a street sweeping contractor, or a municipal manager or similar, you'll want to take a look at all 10. Then, consider implementing the offered suggestions as soon as possible.
Roger Sutherland's top five positive changes a sweeping program can immediately implement:
1. Make sure your sweepers are well maintained and the brooms are changed regularly based on manufacturer recommendations.
Your streets will only be as clean as the machines doing the job are capable. It doesn't matter what make and model sweeper you use if it isn't sweeping at its manufacturer's specifications.
2. Only sweep curbed streets or streets with barriers and focus on high traffic volume streets, even though you might have to sweep the latter only at night.
From a water quality standpoint, there's little sense in sweeping streets without curb and gutter. And, it's important to sweep where the dirt is likely to pile up the worst; i.e., where there's the most traffic. Or, as another example, the streets where traffic might tend to be transporting materials that have been targeted for elimination from the runoff stream.
3. Commit to sweeping in the range of 3-to-7 mph, depending upon specific conditions.
Sweeping too fast for roadway conditions means not doing as good a job at pollutant removal. Keep in mind that sweeping, done at the right speed with the best type of sweeper for the job, is the most cost-effective method of removing roadway pollutants.
A study of structural BMPs by Caltrans indicates the cost per pound of pollutant removed (as Total Suspended Solids, or TSS) runs $10 to $60, not including land costs. In contrast, our sweeping industry studies indicate that newer mechanical broom sweepers reduce TSS in stormwater at a cost of $5 to $10 per pound. Regenerative air and vacuum-assisted sweepers offer an even higher level of efficiency, removing TSS at a cost of $2 to $5 per pound of pollutant that would typically be transported in runoff.
4. Implement and enforce parking restrictions where parked cars are making it difficult to reach the curb.
Vehicle removal is perhaps the most critical component in doing a good job of sweeping. Remember, for every car left in place you essentially lose sweeper pollutant removal for a total of three vehicle lengths, the space needed by a sweeper to swing around the car and then get back to the curbline.
Whatever political and other roadblocks there may be to implementing a vehicle removal program, remove them. Educate your public and your legislators. With education and buy-in by all concerned, the effects will be minimized. Do not make vehicle removal optional!
5. Based on available resources and considering items three and four, above, establish a sweeping schedule and let the community know when and where you will sweep.
The best way to make vehicle removal requirements as painless as possible is to get 'buy-in' by your local community. Make sure your citizens know why you want them to remove their vehicles so the sweeper can be more efficient. Use handouts, your website and community meetings to educate your citizenry of the importance of thorough sweeping. After all, it's for their safety, health and security!
Here are the next five things a sweeping program should consider implementing:
6. Put GPS monitoring devices on each sweeper and monitor each sweeper's day-to-day operation (especially important if contracting out your sweeping).
With the low expense of GPS units, especially as contrasted with the enormous potential benefit, there's no reason not to require that GPS units are in all sweepers. GPS provides security and accountability, two important terms to any municipal administration. When a citizen calls to complain about what occurred with a sweeper or, conversely, that it did not sweep as scheduled, the facts can be presented in a 'proof positive manner.'
7. Link the GPS device to report when the gutter broom is engaged and the machine is actually sweeping, as well as other factors deemed important.
Linking GPS to the sweeping mechanism (e.g., sweeping head down, auxiliary engine operating, gutter broom operating) allows tracking of the actual time it takes to sweep & you may, for example, find particular operators are sweeping in excess of the specified speeds, thus reducing the pickup ability of the sweeper. Or not sweeping at all...
If you have not used GPS in your operations, you may be surprised by the broad range of data solutions the technology can offer. GPS can even be configured to allow operators to notify management about areas of roadway where work is needed. For inspiration, check out a previous WorldSweeper.com article on how the director of Los Angeles County's street sweeping program is utilizing GPS. They've saved a ton of money and are doing a better job for their constituents.
8. Implement or contract out the monitoring of street dirt accumulation throughout your various established sweeping routes.
Because of the significant savings current sweeping technology offers for pollutant removal, when compared to end-of-the-pipe solutions like grassy swales and catch basins and catch basin filter dispersal/changeout, you owe it to your organization to keep track of what you're picking up.
Develop an action plan and then implement it. If you could use some help doing so, contact the authors of this article. Between them, they offer over five decades of sweeping industry experience. Divide your municipality into sensible components when you do; for example, by drainage watershed, by general roadway usage type (industrial, residential, retail) and/or by volume of traffic.
9. Implement or contract out the pick-up performance testing of your existing sweeper models.
Data collection is a key to effective planning so as to maximize funding usage. The only way to know what to expect out of your particular sweeper fleet is to have the machines tested in real world conditions. Do use 'real' street loads, not 'put down mounds of dirt and see how much is left after the sweeper does its best.' Use of simulant, which is repeatable and verifiable, is recommended.
Make sure you account for the small 'fines' that are inevitably left in the street cracks. Although PM-25 and smaller material typically make up less than 15% of the total material on an average street, that smaller debris may be expected to account for up to 60% of the total pollutants you're trying to get rid of via environmental sweeping.
10. Hire a consultant to make the best use possible of the data in 6 through 9, above.
Make sure they have the credentials and verifiable experience required to identify and obtain any additional information needed to establish for you an optimal sweeping program from a stormwater pollutant load reduction standpoint.
Any analysis you conduct should include sweeper type(s) and specific model(s), sweeping routes, frequency of sweeping each route, specific characteristics of the operation, and an annual program budget. Use the resulting information to establish sweeping frequencies and type of sweeper usage such that the marginal cost of the last sweep approaches the higher costs of utilizing other, more costly, end-of-the-pipe solutions.
Street sweeping can be the best investment you make in meeting your pollution reduction goals and permit requirements. However, that can only become true if you sweep with the optimal frequency using the best sweeper for the job. Consider the day of sweeping for solely 'cosmetic' reasons to be officially over. And, with shrinking budgets, you cannot afford to just throw money at storm water pollution runoff solutions without having a realistic expectation of the return you will receive on your investment.
When the authors conducted a series of seminars on this and similar topics several years ago, presented primarily to storm water pollution managers throughout California, the results of an end-of-seminar were particularly enlightening. The majority said they were "doing everything they could" to address increasing storm water pollution problems at the end-of-the-pipe, typically using money collected from increased homeowner and business fees. At the same time, they reported they were only sweeping as often as their limited budgets would allow.
After attending the seminar and learning the facts, the average attendee left determined to gather data and, in all likelihood, at least double their organization's sweeping frequency. Many planned to combine their sweeping and pollution control budgets to better allow this to happen. If your organization is still sweeping your streets only for cosmetic reasons – and you don't know what your sweepers' effiencies are, the amount of material being collected, and the composition of the material in your various watersheds – you are not doing all you can do to meet your EPA and other permit requirements.Roger Sutherland is president of Cascade Water Resources and a principal engineer of the worldwide engineering firm, Wood. PLC. He may be reached by calling (503) 704-0522, or via email sent to: firstname.lastname@example.org.
Roger Sutherland has conducted the only independent testing of current sweeping technology in real world conditions, which he designed and performed for Elgin Sweeper Company. His company also has developed software designed to model sweeper pickup effectiveness, thus allowing organizations to model expected pickup efficiencies without having to do extensive sweeper/runoff basin testing.
Ranger Kidwell-Ross, editor of WorldSweeper.com, is a Masters-level economist with over 20 years of reporting on the power sweeping industry. He is the world's most prolific investigative reporter on the topic of power sweeping.
If you have questions or comments about this interview, or know of other links or information we should add, please, let us know and we can add them in as an addendum to this article.
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