The Hydrodynamic Separator is like a trusted Ford pickup, reliable and easy to maintain. Like a dependable Ford, the Hydrodynamic Separator (HDS) might seem a bit dull next to the shiny new low impact development (LID) practices, but in reality, this equipment is essential to a well-rounded LID plan.
LID practices have dramatically expanded. They focus on landscape-based and water retention designs that reduce runoff volume and mimic predevelopment hydrology to meet goals of runoff reduction and water quality treatment close to the runoff source. Plus regulations often reward developers for infiltration and/or rainwater harvesting. Regulatory agencies also recognize the added value of HDS for upstream protection of sensitive LID practices. Too often HDS has been relegated to traditional, end-of-pipe solutions. Not so fast! Hydrodynamic separators play an important role in developing a treatment train that is essential to the long-term success of LID practices, including infiltration, harvesting, bioretention and storage.
At first a combined approach using HDS can seem counterintuitive to LID, it’s actually a comprehensive, long-term solution that can address problems before they start. Over time, this treatment train approach can reduce the long-term harmful buildup of particles, dirt and trash within LID facilities. For example, one Chattanooga, Tennessee customer embraced this idea and used an HDS to pretreat runoff for an underground rainwater harvesting structure used for surface infiltration landscaping irrigation, toilet flushing, and even a decorative fountain on top of both structures.
As you can see from this example, the best of both a traditional and progressive approach can improve aesthetics, reduce maintenance time and costs for the facility, increase the entire system lifecycle, all the while enhancing property equity to maximize land use from that of a conventional stormwater management approach.
You might also enjoy Comparing NJDEP and NJCAT: Which Standard to Follow?
We are pleased to announce that AquaShield will be presenting at StormCon 2015 in Austin! If you haven’t signed up yet, it’s not too late. There are also special student rates. You can register at http://www.stormcon.com/registration.html.
The AquaShield presentation will explore the predictive performance scaling method for hydrodynamic separators using the Peclet number. A documented hydrodynamic separator performance curve is used as an example to generate a series of predicted performance curves for the same device for median (d50) particle sizes ranging from 45 to 125 microns. Sizing charts are also generated from the predicted performance curves using this Peclet number approach. This method also allows for reasonable comparisons between different laboratory testing programs when different influent particle size distributions were used.
The critical role of particle size in performance testing becomes even more evident when regulatory design guidelines lack a particle size specification for system sizing criteria. In those cases, the real potential to undersize or oversize facilities can lead to a variety of implementation, performance and long-term functionality concerns.
We won’t give away everything! Attend our presentation to get all the information.
Check out this in-depth article about changes coming to stormwater management in California. Under the new rules, there is no one-size-fits-all. Instead, industries, municipalities, and businesses large and small will have to meet a variety of rules. Regardless, they all need to be thinking about how to plan for stormwater management.
By July 1, 2015, industrial facilities throughout California must come into compliance with a new version of the Clean Water Act general permit governing storm water discharges. The new Industrial General Permit is the first revision of that permit in 18 years. In contrast to the old permit’s comparatively permissive standards, the new permit imposes mandatory best management practices, increased sampling requirements, and significantly increased reporting obligations—all of which must be posted to the state’s online database and therefore be made available to the public.
Read the whole article by Facility Executive here: http://facilityexecutive.com/2015/05/st/
Additional regulation means even more need for products and best practices with a proven record of success, confirmed by third parties. You can reach out to our experienced staff at email@example.com to schedule a California specific stormwater management consultation.
A growing number of local stormwater regulatory agencies and engineers are looking to the New Jersey Department of Environmental Protection (NJDEP) and/or the New Jersey Corporation for Advanced Technology (NJCAT) to provide a basis for the approval of manufactured stormwater treatment devices (MTDs). But there are some very important distinctions to be made since they are not one in the same.
Verification versus Certification
NJCAT is a non-regulatory agency that issues independent MTD performance claim verifications for hydrodynamic separators and filtration devices. Only after gaining NJCAT verification will NJDEP issue MTD certification which provides regulatory authority for the device to be sold in New Jersey according to the conditions listed in the certification letter. It is very important to keep in mind that just because an MTD holds an NJCAT verification, it does not necessarily mean that the device is eligible for NJDEP certification. While NJCAT can verify a performance claim, but if that claim does not strictly meet the NJDEP-administered test protocol then the device is not eligible for NJDEP certification. For example, if an MTD’s lab test verification was based on a coarser test sediment particle size distribution than that of the test protocol specification, then that verification would not qualify for NJDEP certification.
Some stakeholders rely on just the NJCAT verification for MTD approval to allow for its specification. Performance claim verifications are issued based on the MTD’s capabilities following a comprehensive peer review and public comment period. However, NJDEP certification letters include a sizing method that is specific to New Jersey. MTD approvals based on the full adoption of NJDEP certifications creates a level playing field for sizing those devices and provides a straightforward approval approach for agencies having limited resources to evaluate MTD performance claims.
Claims and Limitations
NJCAT verifications are based on the actual tested performance capabilities of an MTD in the lab or in the field. But according to New Jersey Stormwater Rules, NJDEP certifications for hydrodynamic separators are limited to 50% annual total suspended solids (TSS) removal efficiency regardless of whether a device was verified by NJCAT to achieve a higher performance rating. In addition, NJDEP assigns 80% TSS removal efficiency for verified filtration MTDs regardless of demonstrating higher performance capabilities.
New NJDEP Certification Rules
All MTD certifications were set to expire on January 25, 2015 unless an MTD gained NJDEP “Final Certification” following the January 2013 lab test protocol. There is no expiration date for a Final Certification. And, if an MTD held NJDEP “Field Certification” as of the expiration date, a new expiration of December 1, 2016 applies. A lab test verification following NJDEP’s 2013 lab testing protocols will be needed to gain MTD Final Certification by December 2016.
Current NJDEP MTD Laboratory Test Certifications and Field Test Certifications are available at njstormwater.org. The NJCAT verification database is also available.
The following table summarizes the comparison between NJDEP and NJCAT.
The first Aqua-Swirl in Bahrain was installed in the parking lot of the now iconic Four Seasons Hotel. Bahrain Bay is the Kingdom of Bahrain’s first master planned mixed-use waterfront community, situated off the northeast coast of the capital Manama. The $2.5 billion development has a masterplan designed to create a fusion of residential, commercial, retail, tourism, and community facilities and public amenities.
The engineering wonder is built on a reclaimed island in the center of Bahrain Bay.
The project included two Aqua-Swirl AS-6s to return clean water to the bay and reduce flooding. Though rainfall is scarce, large amounts of rain tend to fall at once, creating runoff and often flooding. Having a solution that allows for high water flows was essential. The Aqua-Swirl treats flows up to 178L/s.
“Service is extremely important for this client, so ensuring that runoff doesn’t collect on the car lots was a high priority. No one wants cars flooded at this high-rise,” said Sellam Hmadouch, Aqua-Shield’s Middle-East representative.
Check out the awesome photos of this engineering feat below.
NJ.com recently announced that Jersey City was awarded a $260,000 grant toward post Hurricane Sandy resiliency projects. You can read about the six target projects the money will support, including shoreline protection, flood planning and stormwater management techniques in the full NJ.com article.
The AquaShield team is honored to contribute to the ongoing recovery of New Jersey. In 2013, the Aqua-Swirl was selected to meet stringent new construction and stormwater treatment rules for the Route 35 rebuild. At the completion of the project, several large diameter Aqua-Swirls featuring hydrodynamic separation (vortex) technology will be installed in a variety of sizes. You can read more about how AquaShield worked on the project in our case study, “Helping to Rebuild a Community.”
We are really looking forward to this year’s Environment Show of the South in our neighbor city, Gatlinburg, Tenn., April 22-24.
Our team is especially proud that our very own Mark Miller will be representing AquaShield in not one, but two presentations!
He’ll present on Low Impact Development Technology and how to take an approach that works for specific stormwater projects to achieve the best environmental outcomes. This presentation will discuss surface infiltration, subsurface infiltration, rainwater harvesting, biofiltration and much more.
Secondly, Mark will be speaking about registration of antimicrobial pesticides for the removal of bacteria from stormwater runoff. This presentation is downright dirty – digging into the details of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and U.S. EPA pesticide regulations. Yikes!
View the schedule at the Department of Environment & Conservation.
When selecting an HDS device you might just be checking for 80% TSS removal rates and moving on. But what does that mean? Sure the device says it was tested, but on the red clay of Tennessee or the sands of Florida?
All too often MTD selection does not take into account the nature of the particles present in the runoff. Depending on soil types your next project may need to consider that an HDS should not be expected to perform well in a clay or silt-dominated environment. For best results in those cases, a filtration device is needed. On the other hand, an HDS is a good option for coarser materials such as sand and loam.
Check out this free selection tool to pick the right option for your next design.
Easy to use selection tool helps engineers identify hydrodynamic separation (HDS) and filtration options based on soil types.
The Aqua-Swirl AS-13 weighs 14,000 lbs and is our largest, single unit Polymer Coated Steel swirl. Like our smaller models, the Aqua-Swirl AS-13 offers a stormwater treatment system in a single, flow through water quality device to remove course sediment, debris and free floating oil.
The Aqua-Swirl technology has no moving parts (that means lower upkeep cost!) and operates within a single swirl chamber. Even in the largest size, the device is lighter than competing products and requires no assembly onsite. Our products are always hydrostatically tested, strong, durable and leak proof.
Check out these photos of our recent installation for NJDOT on Rt. 35 reconstruction following Superstorm Sandy and a retrofit in a development of townhomes in Murfreesboro, Tennessee.
AquaShield staff keeping you up to date on the latest in stormwater solutions.
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