What manufacturers recommend for their products and how cities inspect and maintain BMPs
Buy a new car from a manufacturer with a reputation for dependability, maintain it properly, and you should get over 100,000 miles of use from the vehicle. However, fail to engage in recommended preventive maintenance, and you can expect headaches—frequent breakdowns and expensive repairs.
The same is true with stormwater best management practices (BMPs). If you purchase products and equipment from manufacturers with a reputation for quality, and if you maintain the products and equipment to manufacturer specifications, they should perform well for years.
Here are some thoughts on proper maintenance programs for various BMPs.
Contech Stormwater Solutions
One of the products offered by Contech Stormwater Solutions is StormFilter. StormFilter targets a full range of pollutants in urban runoff, including total suspended solids (TSS), soluble heavy metals, oil and grease, and total nutrients. Its surface cleaning system prevents surface blinding, which extends the cartridge lifecycle.
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Photo: Minotaur Guardian Service Ltd.
Minotaur inspects units to see if pumping is needed. |
According to the company, maintenance requirements and frequency are dependent on the pollutant load characteristics at each site. Maintenance activities may be required in the event of a chemical spill or if excessive sediment loading occurs from site erosion or strong storms. In fact, it is a good practice to inspect the system after each major storm event.
The company recommends a two-step maintenance procedure:
- Inspection of the vault interior to determine the need for maintenance. Inspection is recommended at least once a year, as well as after major storms.
- Maintenance, which includes cartridge replacement and sediment removal. In terms of frequency, maintenance should occur as needed, based on the results of the inspections. (The average maintenance lifecycle is about one to three years.) Other frequency criteria may include as per regulatory requirement (if applicable), and in the event of a chemical spill.
Tom Gorrivan, a product manager with Contech, offers some additional recommendations for inspection and maintenance. The company offers a variety of maintenance service programs itself, including full-service, where it conducts inspection, compliance reporting, and the actual maintenance. “We can also train a municipality’s staff on how to do their own maintenance,” he states. For StormFilter specifically, the company also offers an exchange program; the customers can do their own inspection, reporting, and maintenance, and Contech will arrange to exchange cartridges for them.
According to Gorrivan, the key to effective maintenance is a good inspection program. “Often, municipalities end up maintaining and cleaning systems when they don’t need to be cleaned,” he says. “We recommend annual inspection, or more frequent as local jurisdictions may require.”
Understanding what to look for during inspection is important. The three main things to look for:
- Make sure the water has drained from the unit within 24 hours after a storm event. If there is standing water in the unit longer than 24 hours, it means that the filter media is occluded.
- If there is more than 4 inches of sediment built up on the vault floor, this will soon begin to clog the filters.
- If there is an appreciable amount (1 to 2 inches) of sediment on the tops of the cartridges, it means the cartridges have been submerged for a prolonged period of time, allowing the sediment to be deposited there. This indicates that the water is not draining down quickly enough.
“If any of these three situations occurs, it is time for cleaning and maintenance,” states Gorrivan.
Frequency of maintenance requirements depends on the part of the country where the system is located and the amount of rainfall the area receives. On average, according to Gorrivan, most units need to be cleaned and maintained once every two to three years. “However, I have seen systems in the ground five or six years that don’t need maintenance,” he says. “In addition, I have seen systems that have been in the ground six or eight months and need to be cleaned.”
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Photo: Minotaur Guardian Service Ltd.
“It’s fine to put these units in the ground, and they are great for the environment, but it you don’t inspect and maintain them, you’re fighting a losing battle.” |
One municipal utility committed to proper maintenance of its StormFilter system is Stockton, CA, which installed the StormFilter storm vault about five years ago. “It is a fairly large unit,” says Christina Walters, the program manager for the city’s Municipal Utilities Department. “In fact, it is the single largest unit we have in Stockton. It has 156 cartridges in it.”
When the unit was first installed, it needed some modifications because of the amount of sediment that was coming in. As a result, about a year and a half after installation, when the modifications were made, Contech also performed some servicing and cleaning. “However, it wasn’t routine maintenance,” she explains.
Last year, Stockton arranged for the first full maintenance of the unit, including servicing and cleaning. “Our maintenance crew did not have any experience with it at the time, so we arranged for Contech to come out to conduct the maintenance, as well as provide training to our crews as they were performing the maintenance,” states Walters. “Since our crews were with them at the time, they now know how to do it on their own.”
Since that time, Stockton’s maintenance crew has taken over the routine maintenance on the unit. The unit is now on a routine maintenance schedule. “Our crews now plan maintenance on an annual basis,” continues Walters. “However, they are out at the site frequently during the year to monitor it.” This includes inspections following large rain events. “You never know what is going through the stormwater system, so it is important to routinely inspect it,” she notes. “They are taking a ‘watch and see’ approach, to determine if the unit needs to be maintained more often or not.”
Stormceptor
Stormceptor units provide stormwater treatment designed to remove sand, oil, and other pollutants. According to company, maintenance involves a number of steps:
- Units should be inspected post-construction, prior to being put into service.
- Units should be inspected every six months for the first year, to determine oil and sediment accumulation rates.
- In subsequent years, inspections can be based on first-year observations or on local requirements.
- Cleaning is required once the sediment depth reaches 15% of storage capacity. However, local regulations for maintenance frequency may vary.
- Units should be inspected immediately after oil, fuel, or chemical spills.
- A licensed waste management company should remove oil and sediment and dispose of them responsibly.
Stormceptor works with a company called Minotaur Guardian Service Ltd. of Brantford, ON, which performs contract maintenance on the units for owners. According to Minotaur, if a unit is not maintained, it will eventually cease to operate, and owners risk a discharge, in addition to the potential for subsequent liabilities. Currently, Minotaur has more than 6,000 oil/grit separators in its monitoring program. “We service some other brands, but we are pretty exclusive to Stormceptor in Ontario and Quebec,” explains Marilyn Shaver, owner-manager of Minotaur. “We incorporated in 2000, and this is our specialty—oil/grit interceptors.”
One key to success in ensuring proper maintenance of the units is educating the general public, she says. In 90% of the cases, she has found, people confuse stormwater with wastewater, so they dump paint, cooking oil, and pool water in storm sewers, thinking all of it will be treated rather than ending up in local lake or river.
Another key is educating property owners (such as condo owners), who don’t even realize they have an oil/grit separator on their property, because it is buried. “A lot of what we do is education, explaining that they do have them on their property and that they need to be compliant with the Ministry of the Environment legislation and municipal bylaws,” continues Shaver.
Once they do become aware of the units, some owners then think they need to pump these out every certain number of months. Minotaur’s message is that pumping is expensive, so why not inspect it first to see if it even needs to be pumped out? “Each site-specific application is different,” she notes. “If an oil/grit separator is in a seniors condo building, which is landscaped, it can only collect what is presented to it, so it will have a slow rate of filling up with sediment.” However, if it is located at a gas station or trucking facility, it will be presented with a lot more contaminants and will likely need cleaning more often.
Garnet Shaver, owner-president of Minotaur, explains the inspection and cleaning process. “We are a monitoring company,” he states. “We inspect units first to see if they need to be pumped. If so, we will then arrange for service as required, but we don’t own our own pump-out equipment.”
Minotaur emphasizes that a monitoring program is a huge cost savings compared to an arbitrary pumping. The cost of an inspection is about one-fourth the cost of a removal, so if an owner can extend the frequency of service from one year to two years, or even three years, there are considerable savings.
Garnet Shaver emphasizes that frequency of inspection and resulting cleaning is site-specific. “A brickyard is different than a condo or a church,” he says. “An oil/grit interceptor can only attempt to capture whatever is presented to it. If it is in a condo parking lot that is paved and landscaped, the sources of sediment are limited. In a residential subdivision, though, sources of sediment are unlimited.”
Minotaur has contracts with some petroleum companies, which have the units at their gas stations. Some of their permits from the Ministry of Environment require monthly inspections. “They don’t necessarily require more cleaning, but they do require more monitoring because of the possibility of a spill,” he says.
Minotaur recommends inspection a minimum of once a year for all sites. However, if a unit has been in the ground for only a year or two, the company recommends inspection twice a year, because it is necessary to get some kind of indication what the accumulation rate is for that unit on that site.
Minotaur works with two companies in Ontario and one in Quebec to do the actual cleaning. There are two classes of sediment in Ontario. The Ministry of Environment allows sediment in the bottom of an oil/grit separator to be treated the same as the sediment in the bottom of a catch basin. However, if there is discoloration or oily film, the sediment must be treated as an oily waste—manifested and sent to a licensed receiver.
Minotaur also works closely with Hanson Building Products in Burlington, ON, which manufactures and installs Stormceptor units. “Stormceptor is a licensed product,” explains Leo Steffler, vice president and general manager, north region, for Hanson. “We formed a relationship with them in the mid-1990s. We manufacture and install the units.”
Hanson realized that, to be effective, the units needed to be maintained. “It’s fine to put these units in the ground, and they are great for the environment, but it you don’t inspect and maintain them, you’re fighting a losing battle,” explains Steffler. “Minotaur approached us with the idea of inspecting Stormceptor units in 2000. At the time, we were looking for someone to inspect and service these units. We wanted to see the units being maintained after our obligation was completed, to make sure the owner would continue to take care of the environment.”
When first installing the units, Hanson performs its own inspections, to make sure the units are installed correctly. “We then hand it over to Minotaur,” states Steffler.
Hanson also works jointly with Minotaur to provide educational seminars to customers across the province.
UltraTech
UltraTech International manufactures a number of products, including several designed to keep debris and pollutants out of storm drains. These include HydroKleen, which is designed to remove concentrated contaminants from stormwater at “hot spot” drains, and Drain Guard, which is designed to keep sediments and other pollutants from entering the water system. Both of these are under-the-grate products. The company also manufactures above-the-grate products, such as Curb Guard and Grate Guard, from which owners can shovel off sediment. “Our under-the-grate catch basins collect sediment, oil, heavy metals, and floating debris,” explains Mark Shaw, co-president of the Jacksonville, FL-based company.
In terms of maintenance, the first step involves visual inspection to determine if the units are full from sediment. This should be done after heavy storm events, or on a timed basis, such as every quarter. “With sediment, you can either actually see it or stick a rod down to measure the depth,” he says.
It can be more difficult to determine when maintenance is needed when dealing with oil. As a result, the company recommends that maintenance should be done on a timetable, based on experience at the site itself. “For example, a Wal-Mart parking lot may not need to change out the catch basins more than once a year,” states Shaw. “However, if you’re a construction site, you may find that a single strong rain event will fill the unit up.”
In the past, with the catch basin inserts and filters, there hasn’t been a way to take a sample of the inflow into the catch basin as well as a sample of the outflow during a real-time storm event. However, UltraTech has recently developed some products and techniques that allow owners to do so. “You can now compare a sample from the inflow with sample from the outflow,” says Shaw. “The comparison will allow you to determine how effective the catch basin filter is, as well as when it needs to be replaced.” For example, if a sampling shows that the unit is typically collecting 75% of oil, but it suddenly drops to 60%, then the unit likely needs to be changed out.
Cleaning Equipment for Sewers and Catch Basins
A number of companies manufacture equipment specifically designed for cleaning stormwater infrastructure. Super Products manufactures sewer and catch basin cleaning equipment, including the Camel Series trucks. Vactor, a subsidiary of Federal Signal, also manufactures a number of sewer cleaning trucks, including combination sewer cleaners, jetters, and vacuum excavation trucks.
Some cities purchase the equipment and perform sewer cleaning themselves, while others contract out such services. “The frequency of stormwater system maintenance really depends on the size of the city and the size of the system,” says Dan Koziczkowski of Super Products. “As a general rule, though, cities should try to perform a general maintenance cleaning of the system at least once a year.”
Again, though, this depends on the system itself. For example, one thing that can determine how often the system needs to be cleaned is the age and status of the lines themselves. “If you have an older system, with cracks or offset joints, you will have more material coming into the pipes,” he notes. These lines will obviously require more frequent maintenance than lines without such problems. And for catch basins, those that are near gravel roads are going to fill up a lot more quickly than those near paved roads.
Good stormwater system maintenance involves flushing the lines and removing the debris, as well as cleaning out the catch basins. “A lot of cities clean the catch basins, but they don’t get around to cleaning the lines themselves,” says Koziczkowski. The problem is that, during the next heavy rain, all of the material that is in the lines will flow back down to the catch basins, and fill the catch basins up again. “As such, it is important to clean the lines and the catch basins at the same time,” he emphasizes.
In fact, good maintenance practices can save time for cities, because they help to avoid backup situations that lead to emergency calls. “Some of the larger cities may be fighting fires all year long with problem areas related to emergency calls, and, as a result, may not get around the maintenance,” he explains. “However, if you have a good maintenance schedule and program, which involves maintaining the lines once every year or so, it really minimizes the number of emergency calls that will end up occurring.”
In sum, if a city finds a way to devote enough time to a regular maintenance program, it will cut down on the amount of time that will be required later to respond to emergency problems, and the result will be less time in total for line and catch basin cleaning. “A lot of our customers work with their local dealers to get information on best inspection and maintenance practices,” says Jared Dippel, product manager for Vactor. “However, we are also available to provide information.”
According to Dippel, Vactor and its dealers suggest to customers that, after every heavy rainfall, it is important to check all known problem spots. “We also recommend that, on average, a system be completely cleaned at least once a year.”
However, this can depend on the individual applications, as well as the size of the system. “For example, smaller systems may only need cleaning once every two or three years,” he says. “Overall, though, we recommend being proactive. Performing routine cleaning is better than having to deal with problems after the fact.”