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Minnesota Moves Forward on Credits for Street Sweeping

by Ranger Kidwell-Ross


Randy Neprash

Randy Neprash, PE, is a water resources consultant who works for the community-focused international engineering services company, Stantec Consulting. He serves as staff with the Minnesota Cities Stormwater Coalition and is Vice-Chair of the National Municipal Stormwater Alliance.

This is a transcription of an interview between Neprash and WorldSweeper's Editor, Ranger Kidwell-Ross.

WorldSweeper has another introductory article to this concept with Neprash in May of 2021 and spoke with Mike Trojan about stormwater crediting in July of 2021.

Randy Neprash: The big news is that we now have two states that are moving forward with providing credits for permitted cities. In addition to Minnesota, New Hampshire is also working on following suit right now, led by a particularly capable researcher, Jamie (James) Houle, who runs the New Hampshire Stormwater Center.

The goal in NH is to be able to measure the nutrients, phosphorus in particular, picked up during street sweeping. Especially, enhanced or frequent street sweeping during periods of time where trees near or immediately adjacent to streets are dropping leaves, flowers – all the things that trees drop into streets and that then can wash into stormwater systems. Those nutrients can be measured and then, based on what the city has removed via street sweeping, the cities can take regulatory credit for removing those nutrients from their system.

That's really important, particularly for cities that have TDML waste load allocations that they need to make demonstrated and quantifiable progress for meeting. We also have research in place here in Minnesota, but I think the folks in New Hampshire have done some work on this as well: NH is looking at only the amount of phosphorus that's removed from the system, which turns out to be quite significant. We have learned that the cost-effectiveness of removing phosphorous through street sweeping is breathtakingly low, on the order of, at some times through the year, less than $100/pound, compared to thousands of dollars a pound for various other stormwater practices.

WorldSweeper: A few years ago we did a story on leaf sweeping, which can really be difficult for sweepers. Plus, when you're sweeping up leaves, it makes a difference whether you're using air-based machines vs. mechanical broom sweepers. However, the point is about half of the people in the the cities I interviewed said "Leaf sweeping is really hard and here's how we handle it" before giving an explanation. The other half said "We quit sweeping before the leaves fall because they're so hard to pick up."

The data you have produced should push a general trend toward sweeping those leaves rather than leaving them on the streets. I never understood the value of leaving them on the streets anyway, because it's not only run-off, but decaying leaves are also slippery, posing an accident danger. Also, the longer the leaves are left in the streets, the more of a problem they become. Cars drive over them, pulverizing them into really small pieces that are even more mobile and degrade more quickly in downstream stormwater systems and can more easily transport into receiving waters.

Randy Neprash: I think there are a few things going on here. I believe we may be headed toward a new generation of equipment designed specifically for removal of large organics – leaves, flowers, seeds, etc. It is a lot more efficient to collect leaves that way, I suspect, though I'm not aware of anybody who's really working hard on this. A dedicated machine for leaf collection would be a lot more efficient than doing it with a street sweeper.

You're right – street sweepers just aren't designed pick up leaves efficiently and easily. With that said, even with the difficulty of picking up leaves with sweepers the beauty of the regulatory credit is doing so becomes encouraged. When the city can take regulatory credit for the nutrients removed by picking up leaves, suddenly the extra effort to do street sweeping during the time when you've got lot of leaves in the curbs and gutters becomes worthwhile. Yes, it's hard to do and it's a nuisance, but if a city can get regulatory credit that's a big pay-off for the city. Leaf removal in the fall suddenly becomes worthwhile.

I live in Roseville, MN, just north of St. Paul. Roseville sweepers came through my neighborhood recently to pick up what were mostly leaves in the street. To accomplish that, they were using sweepers in tandem. They had dump trucks with them for disposal because they're picking up so much material they were constantly having to empty the sweepers. It clearly appeared the public works department had a working system, even though it was more elaborate than a typical street sweeping operation. However, I know any extra trouble and expense was worth it to them because the city is taking regulatory credit under their permits.

Now also new funding streams for purchasing sweepers are available to cities. In Minnesota we have some state level funding that is made available to cities for water quality improvements. Some are grants, some are low interest loans subsidized by the state. Because the state now recognizes street sweeping as a water quality improvement measure, the state is also telling cities that purchasing street sweepers is an eligible expense for these grants and the subsidized loan programs.

EPA logo So with these new funding streams available for multiple cities – we have watershed districts here in Minnesota as well – sometimes these cities and watersheds are going into partnership to purchase sweepers. The state is helping because it recognizes the water quality improvement function. This is also beginning to play out on the national level where I believe the major source of stormwater funding in the United States, at the federal level, is called the Clean Water States Revolving Fund Program (CWSRFP).

Most of the funding consists of low interest loans; however, an increasing portion of CWSRFP funding is going to grants. It is now clear that under federal guidelines CWSRS funding is available for the purchase of street sweepers. Cities can apply through their states; a number of them recognize sweeper purchasing as eligible for CWSRFP funding. Over time, more cities should begin using these programs to obtain financing or grants to support the purchase of street sweepers for water quality improvements. Of course once the street sweeper has been purchased it is available to be used for other purposes as well.

NatlStormwaterAllianceLogo The last piece that's falling into place is a 'Center of Excellence' at the National Municipal Stormwater Alliance (NMSA). This is a program called STEPP, which stands for Stormwater Testing and Evaluation for Products and Practices. Although we have all these stormwater control BMP measures that are being put into place, we've never really had a national program to quantify the effectiveness of how much pollutant retention was actually achieved through proprietary devices. That includes some of the older practices and BMPs like stormwater ponds and rain gardens, but also street sweeping, as examples of practices used by stormwater programs. We don't currently have a research or testing basis that widely recognizes how much pollutant reduction is actually achieved from each one.

One of the focus points for staff is particulate matter (PM) removal – essentially trash removal – in the context of stormwater management. Litter – everything that ends up in stormwater systems and then carries into all our receding water bodies – is a big deal. When staff focuses on trash, one of the things they may be able to do is quantify the relationship between the frequency of street sweeping programs and how much trash is actually being removed and taken out of these stormwater systems. Overall particulate management will no doubt reduce the pollution downstream or in receiving waters. The same principles can then be applied to nutrients. As I've said some of that work has already been done but more needs to be accomplished to find out how much dirt, grit, and various particles currently enter stormwater systems. That's something street sweeping picks up well.

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WorldSweeper: When it comes to street sweeping, total particulate (debris) removal is a factor that doesn't get the level of attention it deserves. In the very exhaustive study done in Florida spanning from 2007 to 2019, which had participation by 14 Florida MS4s, it was determined that street sweeping was by far the most cost-effective way to remove PM, which includes pavement-based debris of all types. Removal via street sweeping was determined to cost $.11/pound. The next best method, catch basin cleaning, came it at $.70/pound, or over six times more expensive.

When it came to total phosphorus (TP) removal, Florida tracked removing a pound of TP at $294, whereas catch basin cleaning came in second at $1,656/pound, or 5.6 times more expensive. Then, for total nitrogen (TN) – another particularly nasty substance we don't want running off into waterways – removal via street sweeping was $189/pound and catch basin cleaning, again the next best, was $1,016/pound or 5.4 times more expensive per pound of removal. Irrefutably conclusive data. Stormwater pros need to see the ridiculously inexpensive cost per pound of PM removal as a collateral advantage because, in addition to being the least cost way to remove nitrogen and phosphorous, it's also by far the least cost way to remove total pavement-based debris.

Randy Neprash: Yes. And then the last piece is how much bacteria is removed by removing debris – particularly fine or damaged materials – from the curb, the gutters and streets. That is also something that street sweepers do really well. When that kind of material stays in place on the street it's a wonderful growth medium for bacteria, which causes real problems. We're moving toward understanding and quantifying how much of that material can be removed through street sweeping. Once we do, then that can go through the chain that I've described earlier and also become a foundation for crediting and funding systems to better support street sweeping.

All these different pieces that we've been working on for years, and talking about for years, are now beginning to fall into place and actually come to fruition. The EPA is really watching this at a national level. I would like, very much, if the street sweeping industry would become engaged with this STEPP program so the information can be coordinated. The industry could no doubt help to inform, guide and also fund work on the STEPP side to lay the foundation for developing the credit system. The industry would also end up with a funding program such that more cities can buy a lot more street sweepers. Plus, we can then use those sweepers to address and improve water quality all across the country. That's the great story that's beginning to fall into place now.

WorldSweeper: Another point is, in terms of the bacteria that can collect on streets – and noted sweeper researcher, Roger Sutherland, agrees on this as well – the real holy grail to us is in two parts: One is the movement of cars. A priority everywhere needs to be vehicle removal prior to sweeping. When vehicle removal is voluntary instead of mandatory what we find are the same cars are there week after week, month after month. The material that gets under those then rots and really contributes disproportionately to the amount of bacteria that will collect on the street. Bacteria invites rodents and other animals to scavenge under those cars to see what's there to eat. There's no way to know what's happening under vehicles that don't ever move out of the way. That's one part, and it's included in the lead article Sutherland and I wrote for the recent annual sweeper issue of PAVEMENT magazine.

Part two is an increasing concern about getting microplastics out of the runoff stream. I recently worked with the U of Santa Barbara on that topic. They have received a small grant to investigate BMPs on that, which spurred a request for an even larger one due to the scope needed. I believe microplastics need to be added to any study that might take place. I recently researched and then wrote an article on the topic and the facts were quite startling and not in a good way.

Please allow me a moment of being on one of my 'soapboxes:' The power sweeping industry needs, in my educated opinion, some sort of X-Prize dangled in front of it, one designed to improve the machines currently in use. Right now the industry is still, – even with water quality getting more and more important – filling sweeper dust suppression systems with perfectly good drinking water; spraying it onto the street to keep dust down; picking it back up contaminated with all manner of nasty stuff; and, then trundling it off to dump into a waste facility someplace. That process has to end!

The industry needs an incentive to move to being able to operate largely dust free without the use of water. The only way I see that happening is if an incentive is put out to the sweeper manufacturers. I don't know if that's by the EPA or via the private sector, but an incentive is needed for manufacturers to come up with a machine that can be more dust-free, yet not using water to accomplish it, than anything that's out there right now.

Randy Neprash: Interesting stuff. All your comments I agree with completely, and I really want to thank you for leading me to the article WorldSweeper did on the Florida study. Those are really impressive documents and materials. John Sansalone, the lead researcher in Florida, does amazing work and it shows in that paper.

With the cars, it's an interesting problem, and I agree that there are some cities where that's really significant. What we see here in Minnesota, although I honestly don't know how typical this is, is that in the core urban areas of places like the Twin Cities Metropolitan area (Minneapolis and St. Paul) the streets are used very heavily for parking cars, particularly overnight, but also during the day as well. Those cars are just a huge problem when it comes to street sweeping – not insoluble, especially now that we all have cell phones with apps available. That allows us to, for the first time, reach specific, targeted people geographically/positionally.

An interesting component is as soon as we get into the residential neighborhoods of the suburbs, where everybody has a driveway and a garage, we have hardly any cars on the streets. As a result, in those areas the street sweeping protocols are much simpler and more efficient because the cars aren't much of an issue. So, although it's a problem in some places I suspect we have a lot of communities where cars are not a real big deal. As for microplastics, they are certainly an example of a type of emerging contaminant. We also have other types of new contaminants that we're beginning to understand and to struggle with.

In my mind, a change that needs to take in place in how stormwater folks think about the landscapes – the urban/suburban landscapes they're working with – is to consider streets as a 'collection opportunity.' We have a wide-ranging amount and type of material that drop onto the street, but then we also have a whole variety of materials that wash onto the street, you know, across lawns, down driveways, across sidewalks, out of parking lots. These materials end up in the street and stay there for a limited amount of time, in a lot of cases, until a pretty good-sized storm event comes along sufficient to dislodge this material off the street and into catch basins and stormwater systems.

I believe there's value in thinking about that collection of materials in the streets as an opportunity. We then design systems, probably largely based on street sweeping, to remove that material when it's been there for relatively short period of time. I suspect there's payoff for a really wide range of different types of pollutants if we think in those terms and design programs and practices to get that material up off the street.

WorldSweeper: I agree with you completely on that. It's interesting that a number of different challenges posed by different chemicals are now emerging as problems. Nobody I know of has addressed the issue of plastic runoff until recently, for example.

Randy Neprash: In the Pacific Northwest, where you're located, it's widely known there are chemicals that are highly toxic to salmon. In that situation, too, if we can pick it up and remove it right away after it hits the street, we might be able to make a significant dent in harm to salmon. There are also a number of substances causing problems in addition to the ones we've already discussed; we're seeing copper from brake lines, zinc pollution from tires, and add to all of these a whole bunch of chemicals that wear off of various parts of motor vehicles.

WorldSweeper: I founded American Sweeper magazine in the early 90's. It was the first magazine for the sweeping industry. I started publishing that after working with Schwarze Industries, Inc., back when the Schwarze family still owned it. I had learned about what sweepers were and what they did. Over time, I recognized that many, if not most, public works managers were acting as though they were still picking up poop behind horse-and-buggy rigs rather than worn clutch plates, brake linings, tire wear particles and so forth.

It seemed obvious to me that an amazing amount of material had to be coming from internal combustion vehicles and that most all of it would be worse for the environment than horse poop. That's something that people don't really think about: To take just one example, we have to replace our tires – why is that? Oh, the tread's down; where'd the tread go?

Randy Neprash: Right, and it's a small amount of material from each tire, but think about how many millions of tires we have out on our roads.

Addendum Note by WorldSweeper: The answer for 2020, the latest date for which data is available, is about 275 million cars were registered in the U.S. VehiclesInUS According to the latest data from Tire Business, in 2019 a total of $48 billion dollars was spent for new tires just in North America.

Randy Neprash: One of the ways I think about all this is it would be very nice to have incentive awards programs, interesting grants. At some point we may be able to get some of the philanthropies that are particularly interested in water quality issues to help support some of this work. However, the biggest decision payoff in my mind comes if we can build a research foundation and then a regulatory crediting system. That would allow linkage to the various funding sources to support water quality work that are already in place at the federal/state levels – in addition to all the money that cities on their own are putting into water quality improvement. That would certainly, as you have said, expand the demand for street sweepers around the country.

Cities will be looking to buy more street sweepers. However, they will also be looking for street sweepers that have improved functionality; picking up additional material, perhaps specialized equipment to pick up just leaves. If we are successful in building the demand and the market for street sweepers, I'm of the opinion that the industry will respond, because that's how capitalism works. When it's structured properly and the market demand is in place, industries tend to be very responsive. I think that's what the goal is here because that's where the biggest set of rewards are to be found.

WorldSweeper: I have to agree with you completely about that. Getting the manufacturers together to recognize that is absolutely huge. One of the things that can move us toward that, in my belief, is to combine the stormwater management and sweeping departments. That's because now, with available funding, many cities have developed funding sources to address stormwater. As a result, they tend to have quite bit of money in their stormwater department budgets. Unfortunately, they're using those dollars in ways that are not as efficient because that's what they know.

If you combine those two departments then the in-fighting between departments that often exists now is eliminated. The stormwater people are the ones who are incentivized to sweep at the right frequency, as well as to become knowledgeable about which machines to use. Example: If you sweep once per year you're going to pick up a lot of material; if you sweep once an hour that's reduced to hardly anything even though your costs will be the same per sweep. It should be the stormwater department's task to figure out where the 'sweet spot for sweeping frequency' is.

How many times you should be sweeping will be determined by doing an educated cost analysis that factors in the data about that relatively more cost-effective method. Figure out much it costs you per pound to pick up what you're after at a given sweeping frequency; then, at the point where you've increased your sweeping frequency to where the cost per pound is equaling or close to your next best method, let's say catch basin filter cleaning, then you quit sweeping and put resources elsewhere.

Randy Neprash: I couldn't agree more. What we've done here in Minnesota is to look at a couple variables both of which focus on nutrients. Essentially, if I'm picking up large organic material mostly coming from trees, one of the variables is "What is the percentage of tree canopy cover is near and adjacent to the streets?" We have satellite data run through GIS systems; the percentage of canopy cover is then associated with each street, each neighborhood. Where you have more trees, we sweep more frequently, because more material is in the streets.

The other piece is to not think in terms of street sweeping frequency as a constant during the entire sweeping season. Here in Minnesota, we stop sweeping when everything freezes. That still leaves seven or eight months where we are sweeping. You increase the sweeping frequency in the spring when you have seeds and flowers drop from trees. You cut back in the summer when there's a lot less organic material and then you ramp the frequency back up again in the fall. Those are examples of how we can make sweeping programs more efficient. But that's just a focus on nutrients.

One final comment is this: The basis of the current STEPP program is largely focused on the companies that do manufactured stormwater treatment devices. These are hydraulic separators; underground filters; there's a whole growing list of industry manufacturers that are producing devices that are being used by cities and other local governments to improve water quality. That is currently the foundation for quantifying the performance of these kinds of devices. Right now, those manufacturers are the largest funding source for the STEPP program. Given the results we're seeing, it's clear that the street sweeping industry should also be a participant, and a funder of STEPP, and I would very much like to see the beginnings of a conversation between the STEPP program and the sweeper manufacturers and I suspect you're one of the people that could help make that happen.

WorldSweeper: I have a long proposed that the industry needs to put together a 'manufacturers council' of some kind in order to promote the knowledge that is now out there in terms of what sweepers can do compared to what other technologies can do. As you have articulated so well, spreading this knowledge means there will be an expansion of sweeping frequency so it could only be in all of the manufacturers' best interests to do that.

Randy Neprash: I think the industry has been somewhat reluctant because it hasn't been entirely convinced that there really is a potentially strong market on the stormwater side to support sweepers. However, with the latest studies that information is falling into place for the stormwater community and its interest is becoming real. That's the story to carry to the sweeper industry, which should convince them that enormous market expansion potential exists here.

WorldSweeper: That's very good. However, we sorely need an actual evaluation of sweeper capabilities, in terms of manufacturer and/or sweeping type for different types of sweeping. We now have mechanical broom, vacuum and regenerative air. For this purpose it would seem ideal to develop and test some combination. I believe most stormwater pros currently do not have the info they need to recognize which sweepers are going to be better for which tasks. Not just different manufacturer machines, but the relative use and value of the differing sweeper types.

One of the problems Minnesota and the rest of the snow belt states have for spring cleanup is a need for heavy-duty broom sweepers. Unfortunately, the tendency is to then continue using those machines for the rest of the year. When it comes to stormwater pollution abatement, broom machines will not be removing small-micron materials with the same efficiencies. Although Dr. Sansalone's work in Florida was groundbreaking, he didn't know to design it so as to keep track of which types of sweepers were in use in the nearly 20 different cities. He apparently didn't realize the value in segregating air and broom results. If he had, we'd now have a real snapshot of which of those types of machines were doing a better job in terms of pollutant removal.

You mentioned tandem sweeping. In the '90s there was a study in Portland, Oregon, that included tandem sweeping and demonstrated "sweeping can significantly decrease contaminated sediment in the runoff stream when sweeping methods are tailored to the problem of pollution rather than to just the collection of litter."

We need data such that stormwater pros can recognize what type of sweeper to use to get best results. Unfortunately, the sweeping industry is driven by California's Air Quality Management District (AQMD) testing process that occurred many years ago. Even though they only put down 10% of paint pigment, which was used as the test's PM-10 surrogate, they called the sweepers that passed 'PM-10 Certified.'

I was onsite for the testing and talked to AQMD management about it. Schwarze Industries, which I was representing at the time, had a machine called the 'EV' that was by far the best pickup machine out there. By employing a series of filters it also didn't use water for dust suppression and was something like 99% efficient. However, it was $250,000 when the rest of the sweepers in the market were @ $100,000. I asked "What happens if the EV performs clearly above the rest?" I was told that AQMD's mandate was to then lower its testing qualifications such that many manufacturers and many models would pass.

As I recall a passing grade was a 70% overall pickup level; that means that since only 10% of the 'street dirt surrogate' used was as small as PM-10, a sweeper passing the test could have left all the PM10's on the ground and still pass. And, to my knowledge, every sweeper – mechanical broom, vacuum, regenerative air; every make and every model ever tested by the manufacturers – found a way to pass that test. It was widely rumored that clandestine modifications were performed to enhance performance on some of the sweepers – especially broom models – that were tested.

For stormwater guidance we definitely need a new round of testing with a different protocol. Plus, by now so many new makes and models have been grandfathered in by the AQMD that we don't really know what a PM-10 Certified sweeper's capabilities actually are. A new testing protocol needs to determine, in addition to total removal rate, how well a given make/model of sweeper can remove nasties like phosphorus, nitrogen, zinc, tire particles, microplastics: whatever is seen as important. For stormwater sweeping we need a new testing process that truly ranks the different machines in terms of their capabilities. Make it replicable without huge expense so re-testing can be done. That would incentify manufacturers to make needed changes to better compete in the marketplace.

Randy Neprash: Definitely some good insights worth thinking more about. If a particular small-micron material can be picked up in significant amounts, right now nobody really knows what the chemical constituency of those materials are. How much is composed of the various toxic chemicals coming off of motor vehicles?

STEPP The folks here in Minnesota who looked at nutrients worked out a pretty good formula and it wasn't all that complicated. Their innovative approach is to take a spectacularly heterogeneous collection of materials, otherwise known as debris collected via street sweeping, and convert it into a heterogeneous set of sample materials that could be analyzed for their nutrient content. Similar work could be done to find out what else is in those street sweepings that we want to remove effectively from our stormwater systems. I agree completely about the need for more testing and that is exactly what the STEPP program is all about. One of the beauties of the STEPP program is that it is now very closely associated with a new stormwater committee that is part of ASTM – The American Society of Testing and Materials. ASTM is probably the most widely recognized international body that works out testing protocols.

The engineering specifications include multiple references to ASTM standards and protocols. All of that now is being included in the STEPP work because of its association with the new ASTM stormwater committee. The last piece of it is the STEPP program also offers an independent – and therefore more certifiable – testing protocol than testing done by manufacturers.

Everybody has a little bit of skepticism, sometimes well founded, about the results of product tests that are organized and run by a particular company. A given company's product tends to do really well when they themselves do the test. If a program offers an opportunity for the testing to be done in an independent, and thus more credible, fashion, results then become more valuable for the regulators. The same can also be said for all the regulated parties who need to know how much progress they're making toward regulatory compliance.

WorldSweeper: I agree completely. Plus, not only is the AQMD testing out of date; it's also completely meaningless. If it's a pass/fail process with no relative results and then every product that tests passes, how can the results have any meaning at all? Still, after all these years manufacturers at trade shows will have some sort of PM-10 Certified sticker in their window. Some place like ASTM needs a new testing protocol that covers air quality as well as pickup capability. Plus, if a testing process is well quantified through some place like ASTM, manufacturers could re-test through independent testing labs when they tweaked their sweepers or came out with new models. Testing is now not really available through AQMD.

Randy Neprash: You have a lot of knowledge in that regard. If we can get the manufacturers engaged in the STEPP program – and then we can get the STEPP program and the ASTM committee to work on protocols for testing street sweepers – it will be important that you and Roger Sutherland are engaged in that process to make sure that it's effective and credible.

WorldSweeper: Yes, some things are very obvious to us, having been working on this for years. Many aspects are just not intuitive to somebody on the outside looking in. With new technology other areas can be improved now, too. For one, we need an app system designed to keep vehicles from having to move for four hours, the now standard practice. With a well-defined app system hooked in to the city's database, people can sign up for a notice that says "the sweeper's coming tomorrow" and then another that says "the sweeper's a mile away." At that point someone can go shopping for awhile – or even just drive around the block – before coming back.

At the same time put front-mounted cameras onto the sweepers. If there's a car in the way take a picture of the license plate and send them a ticket. If it's not in the way when the sweeper goes past then no problem. There are a lot of social media complaints about seeing the sweeper go by, re-parking and still getting a ticket because the parking ticket people were 20 minutes behind the sweeper. Or it was still within the four hour timeframe. With today's technology there's no need to ticket cars that have been moved before the sweeper passes.

Randy Neprash: I'm aware of multiple cities here in Minnesota that already have location devices mounted on all their sweepers and are systematically tracking and mapping all the work that they are doing. Those sort of sweeper location systems can be integrated very effectively with the sorts of app you're talking about.

WorldSweeper: Also – and especially since these cities are going to have higher costs due to sweeping more than they have been – there are some other economies a sweeper can offer. For example, put a touchpad system into the vehicle such that an operator, when a roadway problem is seen, can notify whatever city department is tasked to fix it. If there's a branch hanging too low over the road he pushes number four on his pad. When a sign is down, he pushes number three; perhaps an emerging pothole is a two.

For each, a notice is automatically sent to the department responsible for fixing the problem. A GPS stamp shows the work crew where to go. Right now many cities have guys in pickup trucks that drive around all of the neighborhoods at least twice a year so as to note these types of items. With sweeping, you can have those things discovered earlier and then fixed before it's more expensive to do so or an accident is caused.

Randy Neprash: One last story: The University of Minnesota folks who are doing the nutrient work did most of their work in the city of Prior Lake, a suburb of the Twin Cities. One of the things they reported was that the street sweeper operator was just thrilled to know that one of the results of his work was improved water quality in the city's stormwater systems and lakes. It added a whole new positive dimension to his work to know that he was helping to reduce runoff pollution and so improve water quality. I think that's wonderful.

WorldSweeper: Exactly! You're training sweeper operators to realize that when it comes to pavement based-material they're the first line of defense for maintaining water quality. Also needed are development of some standard education modules. I go back to the idea of a sweeper manufacturers' council that would develop those to educate particular school grades about the value of street sweeping; the importance of water quality; the importance of not throwing litter onto the ground, etc. Stormwater/sweeping departments also need to have good outreach to people on their websites. Around 35 years ago, when I first got into the power sweeping industry and started learning about this topic, there was this talk on the fringes about how water was going to be the new oil, just wait. Well, that time has come.

I've enjoyed this wide-ranging conversation that has covered so many topics centering on street sweeping; however, I don't think that's the real topic. I'd say the real topic is water quality, which is vital to maintaining quality of life here in the United States and around the world. A reported 80% of diseases and 50% of child deaths worldwide are related to poor water quality. Just here in the U.S. around 6,500 miles of new roadways are built each year. The problem of pavement-based pollution runoff can only increase. My hope is that the street sweeping industry – by collaborating with the stormwater industry – can evolve to 'be all it can be' in terms of pollutant removal prior to runoff.

Randy Neprash: I agree completely, Ranger. Let's go forth and change the world!

In the event you have questions or comments for Randy Neprash, he may be reached via email sent to To reach Ranger Kidwell-Ross send to editor@

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