A drop-in stormwater drain filter is chosen by matching the media to your site's contaminants first, then fitting the format to the catch basin itself. Here's how that selection process works, from site assessment through install.
Choosing the right stormwater drain filter starts with identifying what's actually in your runoff and which permit is driving the requirement, not with picking a product off a shelf. A catch basin insert that only screens trash and sediment won't touch dissolved metals, phosphorus or bacteria, so the selection process has to start with the pollutant profile and work outward to the hardware. Abtech Industries builds that process around a simple rule: the media follows the contaminant, and the format follows the site.
Step 1: Identify the contaminant and its fraction
Most stormwater pollutants fall into one of two physical states — particulate (suspended solids, trash, debris) or dissolved (metals, phosphorus, hydrocarbons in solution, bacteria). Sediment control alone addresses the particulate fraction. It does nothing for the dissolved fraction, which is often what triggers a benchmark exceedance under an NPDES Multi-Sector General Permit (MSGP) or a municipal separate storm sewer system (MS4) permit.
- Metal recycling, metal fabrication and junkyard facilities typically see iron, copper, zinc and arsenic in runoff from exposed scrap, cutting operations or equipment yards.
- Municipal wastewater operators working toward discharge or reuse limits often need phosphorus removal to address nutrient-driven permit conditions.
- Marinas, boatyards and fueling docks generate hydrocarbon sheen and fuel residue that standard sediment screens pass straight through.
- Facilities under bacteria-related TMDLs or MS4 bacteria targets need media that addresses E. coli, fecal coliform or enterococcus, not just solids.
Abtech's Smart Sponge® media family is organized around this same logic rather than a single all-purpose formula. Standard Smart Sponge® is a hydrophobic, oil-attracting media for hydrocarbons. Smart Sponge® HM targets dissolved metals — lead, zinc, copper, arsenic and selenium — along with phosphorus, which makes it the media most relevant to metal recycling yards, fabrication shops and nutrient-limited wastewater discharges. Smart Sponge® Plus is an antimicrobial media aimed at bacteria such as E. coli and coliform. Smart Sponge® AC handles dissolved hydrocarbons and organic compounds that raise total organic carbon, and Smart Sponge® Quanta™ is built to capture PFAS. Because more than one contaminant class often shows up at the same outfall, several of these media can be combined inside a single format.
Step 2: Match the format to the structure, not the other way around
Once the media is identified, the next question is what holds it. This is where the site assessment matters: catch basin geometry, typical and peak flow rates, available space and maintenance access all determine which format fits. Abtech's media deployment options and installation formats cover a wide range of existing infrastructure:
- Ultra Urban® Filter catch basin inserts — custom-fabricated to fit the specific shape, size and design of a given basin, for both retrofits and new construction.
- Bulk Smart Sponge® media for loading into a customer's existing pressure vessels, skids, tanks or vaults.
- Smart Pak®, Smart Bags and EOP (end-of-pipe) units for vaults, channels, outfalls and discharge points.
- Skid-mounted Smart Skid systems, which are installed with pumps, pressure and flow controls rather than operating passively.
- Smart Sponge® skimmers, booms and Smart Drum units for capturing floating oil, fuel and sheen in open water or at fueling docks.
The Ultra Urban® Filter is the format most directly relevant to a drop-in drain filter question. Because it's custom-fabricated rather than one-size-fits-all, it can retrofit into existing catch basins without excavation, pumps or external power. Stainless steel inserts carry a 20-year warranty on the hardware itself — that warranty applies to the stainless steel component, not to media performance or permit outcomes. Smart Skid systems, by contrast, are active installations with pumps and controls, so they're suited to higher-volume polishing applications rather than a passive catch basin swap.
Step 3: Confirm trash and sediment capture status where it's required
Some jurisdictions set a separate bar for solids capture before dissolved-pollutant treatment is even considered. California's Full Trash Capture requirements, for example, specify that a device screen out trash and debris down to a defined particle size at the design flow rate. A drop-in insert intended to satisfy that kind of requirement needs to be evaluated for its screening performance and its total suspended solids (TSS) handling, separately from whatever dissolved-pollutant media it may also carry. Regulatory frameworks continue to evolve in this space — for instance, states have been revisiting their stormwater rules to address new pollutant categories and construction-site requirements — which is one more reason to confirm current permit language with your regulator or environmental consultant rather than relying on a product spec sheet alone.
Step 4: Verify performance on your own water before committing to scale
Site assessments review contaminant concentrations, flows, available space, effluent targets and maintenance access before any system is specified. For wastewater polishing, PFAS treatment or other higher-stakes applications, Abtech also offers laboratory column testing on the customer's own water sample, followed by pilot testing before full-scale deployment. This step exists because runoff composition varies by site — a catch basin downstream of a fueling area behaves differently than one collecting roof runoff — and testing the actual water, rather than relying on generic contaminant assumptions, reduces the chance of specifying the wrong media.
Step 5: Install and plan for access
Because the Ultra Urban® Filter is fabricated to match a specific basin's dimensions, installation typically involves setting the insert in place without excavation or structural modification to the basin itself. Maintenance access is part of the format decision made during the site assessment — a basin in a high-traffic parking area will need a different access plan than one along an airfield catchment or a marina dock. Facilities should expect to schedule periodic inspection of trash, sediment and media condition, with the frequency driven by site traffic, rainfall patterns and the pollutant load rather than a fixed calendar.
Frequently Asked Questions
Can one catch basin insert handle metals, bacteria and hydrocarbons at the same time?
Several Smart Sponge® media types can be combined within a single Ultra Urban® Filter or other format when a site's water carries more than one contaminant class — for example, Smart Sponge® HM for dissolved metals alongside standard Smart Sponge® for hydrocarbons. The right combination depends on what the site assessment and, where applicable, column testing show in the water itself.
Does a drop-in filter replace sediment and trash capture, or work alongside it?
Trash and sediment capture addresses the particulate fraction of stormwater, while dissolved-pollutant media such as Smart Sponge® HM or Smart Sponge® Plus addresses what sediment control leaves behind. Where a full trash capture standard applies, the insert's screening performance for solids should be confirmed separately from its dissolved-pollutant media.
Is bacteria removal media different from metals or hydrocarbon media?
Yes. Smart Sponge® Plus is an antimicrobial media formulated for bacteria such as E. coli and coliform, which is a different treatment mechanism than the metals-binding chemistry in Smart Sponge® HM or the oil-attracting chemistry in standard Smart Sponge®. A site with a bacteria-driven permit condition needs the antimicrobial media specified, not substituted with a metals or hydrocarbon product.
Do all of Abtech's formats work without power?
No. Catch basin inserts like the Ultra Urban® Filter and formats such as Smart Pak®, Smart Bags and booms are passive. Smart Skid systems, however, are installed with pumps, pressure and flow controls, so they're an active format suited to different flow and space conditions than a drop-in basin insert.
How do I find out which media and format fit my site?
The starting point is a review of your contaminants, flows, available space, effluent targets and maintenance access. You can schedule a site assessment with Abtech to work through that review before any media or format is specified.