Catch basins for drainage collect and channel stormwater runoff, but without a filter insert, they pass hydrocarbons, metals, and other priority contaminants directly into receiving waters. This walkthrough explains how Ultra-Urban® Filter inserts and Smart Sponge® media work inside catch basins —
Catch basins for drainage intercept stormwater at the point of entry, but a basin alone does not remove dissolved hydrocarbons, heavy metals, PFAS, or nutrients — it only slows and redirects flow. Abtech Industries' Ultra-Urban® Filter inserts drop directly into existing catch basins, adding passive Smart Sponge® filtration without pumps, power, or civil construction. The process from first contact to in-service insert follows a clear sequence, and understanding each stage helps facility managers and permit holders plan realistically.
What a Catch Basin Does — and Where It Falls Short
A catch basin is a below-grade inlet box, typically set at a curb or low point in a paved surface, that intercepts sheet flow and routes it into a storm drain network. The sump at the bottom of the basin traps coarse sediment and floating debris, which is why routine cleaning extends the life of any downstream treatment. What a standard basin cannot do is capture dissolved or emulsified contaminants: oil, fuel residue, dissolved metals, nutrients, and PFAS pass through with the water column and reach outfalls, channels, or receiving waters unimpeded. For municipalities, departments of transportation, airports, and marinas operating under MS4 or NPDES permits, that gap is a compliance liability. A filter insert addresses it at the source — inside the basin itself — before contaminated runoff travels any further.
Step 1 — Site Assessment and Contaminant Profiling
Every solution starts with site conditions, not a catalog selection. When an operator contacts Abtech, the team asks for details about the catchment: paved surface type, estimated drainage area, known or suspected contaminants, discharge permit requirements, and any existing maintenance constraints. Airports dealing with deicing-season runoff have different contaminant profiles than municipal street drains or marina deck drains. Sharing that context up front — contaminant targets, flow conditions, and permit language — allows the team to evaluate the application accurately. Abtech responds within one business day. No site visit is required to begin the evaluation, though a pilot program may be recommended for complex or high-variability sites before full-scale deployment.
Step 2 — Media Selection and Insert Sizing
Smart Sponge® is a proprietary filtration media engineered to target specific contaminant classes. Because different sites carry different pollutant loads, the media can be selected and combined within a single insert to address multiple treatment objectives simultaneously. A paved municipal catchment may prioritize hydrocarbon and metal capture; an airfield may need to address deicing-season runoff chemistry; a marina deck drain may focus on fuel sheen and bilge-related hydrocarbons. The Ultra-Urban® Filter insert is sized to fit the basin's existing opening — no basin modification, no new infrastructure. The insert frame suspends the Smart Sponge® media basket inside the basin so that all incoming flow passes through the media before reaching the sump outlet. High-flow performance is a design requirement: the system handles up to 40 GPM per square foot with under 1 PSI of back pressure, so even heavy storm events move through without surcharging the basin.
Step 3 — Pilot Testing (When Applicable)
For sites with complex contaminant mixtures, variable flow regimes, or stringent permit thresholds, Abtech may recommend a pilot evaluation before committing to a full network deployment. A pilot installs inserts in a representative subset of basins, collects influent and effluent data over several storm events, and confirms that the selected media configuration meets discharge targets under real-world conditions. This stage reduces uncertainty for permit holders who need documented performance data before presenting results to regulators. Not every project requires a pilot — straightforward applications with well-characterized contaminants often move directly from media selection to full deployment — but the option is available and the team will flag when it is advisable.
Step 4 — Drop-In Deployment
Installation is the least disruptive stage of the process. The Ultra-Urban® Filter insert drops into the existing basin opening — the same opening used for routine cleaning — without excavation, electrical hookups, or mechanical connections. Crews lift the grate, lower the insert frame into position, and replace the grate. No pumps. No power supply. No bypass plumbing. For a network of municipal storm drains or a row of airfield catchment basins, a maintenance crew can work through multiple units in a single shift. The insert sits below the grate and above the sump, intercepting all incoming flow. Because Smart Sponge® media is hydrophobic and oil-loving, it begins capturing hydrocarbons on contact and binds them permanently into a stable solid — the media does not release captured contaminants back into the water column.
Step 5 — Ongoing Inspection and Media Management
After deployment, inspection intervals depend on site-specific factors: catchment size, storm frequency, sediment load, and contaminant concentration. Good practice is to inspect inserts during or after significant storm events and as part of any scheduled basin cleaning. During inspection, crews check that the insert frame is properly seated, that the media basket is not compacted by accumulated sediment, and that the basin sump below the insert is cleared of debris. Because Smart Sponge® permanently binds hydrocarbons rather than releasing them, spent media is managed as a solid — there is no liquid phase to handle or dispose of separately. When media reaches capacity, the basket is removed and replaced; the insert frame stays in place. This low-maintenance cycle is what allows municipal crews to manage large networks without significant added labor.
Frequently Asked Questions
Do Ultra-Urban® Filter inserts require any power or mechanical equipment to operate?
No. Ultra-Urban® Filter inserts are entirely passive. They require no electrical connections, no pumps, and no mechanical components. Stormwater flows through the Smart Sponge® media under gravity, and the system operates through every storm event without operator intervention.
Will the insert restrict flow and cause the basin to back up during heavy rain?
The system is engineered for high-flow conditions. Smart Sponge® media handles up to 40 GPM per square foot with under 1 PSI of back pressure, which means the insert does not create meaningful flow restriction under typical storm loading. For sites with unusually high peak flows, the site assessment stage evaluates whether the selected configuration is appropriately sized.
Can one insert address multiple contaminants at the same time?
Yes. Smart Sponge® media can be selected and combined within a single insert to target multiple contaminant classes — hydrocarbons, heavy metals, nutrients, PFAS, bacteria — within the same treatment pass. The specific media combination is determined during the site assessment and media selection stage based on the site's contaminant profile and permit requirements.
How do I know when the media needs to be replaced?
Inspection intervals are site-specific and depend on catchment size, storm frequency, and contaminant loading. During routine basin cleaning, crews check the media basket for sediment compaction and assess whether the media has reached capacity. Because Smart Sponge® permanently binds hydrocarbons into a stable solid, spent media is handled as a solid waste — there is no liquid phase. When replacement is needed, the basket is swapped out and the insert frame remains in place.
Does Abtech work with marinas and ports, or only municipal stormwater programs?
Abtech serves both. For marinas, ports, and harbor operators, Smart Sponge® floating booms deploy around fueling docks and slips to capture fuel sheen and bilge-related hydrocarbons, while deck drain inserts treat shore-side runoff. For municipalities, DOTs, and airports, Ultra-Urban® Filter inserts address paved catchment runoff across storm drain networks. The site assessment process is the same regardless of application type — share your site conditions and the team will evaluate the appropriate product and media configuration.