Learn which non-deicing pollutants show up in airfield stormwater, what the permit requires, and how to match treatment media to oil, dissolved metals and dissolved organics at fueling areas and aprons.
Beyond deicing fluid, airfield stormwater carries fuel, oil and grease, particulate and dissolved metals, and organics from fueling, maintenance, equipment-washing and apron areas. Sediment controls are built for particulates, so the dissolved fraction can pass through them. Where your sampling shows dissolved pollutants, match media to the pollutant: hydrophobic media for oil and hydrocarbons, Smart Sponge® HM for dissolved metals, and Smart Sponge® AC for dissolved organics.
Non-deicing pollutants and where they come from
Start the inventory with the activities EPA lists for air transportation facilities in its Sector S fact sheet: servicing, repairing and maintaining aircraft and ground vehicles, and equipment cleaning and maintenance, including mechanical repairs, painting, fueling and lubrication. Runoff from areas where these happen can discharge pollutants directly to a waterbody or through the storm sewer.
Common pollutant sources by area:
- Fueling areas and aprons: fuel, oil and grease, and the sheen they produce.
- Maintenance areas: oil, grease and hydrocarbons from repair and lubrication work, and metals from repair and painting.
- Equipment cleaning areas: oil and grease, metals, and organics that raise total organic carbon.
- Runway and taxiway edges: sediment, with any metals and hydrocarbons that travel with it.
Always note whether a pollutant is particulate or dissolved. Particulate metals and oil can settle or separate. Dissolved metals such as zinc and copper, and dissolved hydrocarbons and organics, do not.
What the permit requires for these pollutants
The Sector S activities above all require coverage under an industrial stormwater permit. Common requirements are a written SWPPP, implemented control measures and a Notice of Intent. The control measures include site-specific BMPs, maintenance plans, inspections, employee training and reporting. The SWPPP is the document where you assess each pollutant source and say how you will control it.
Before you compare a sample to a benchmark, confirm the flow is covered by the permit. EPA states that aircraft, ground vehicle and equipment washwaters, dry-weather discharges from deicing/anti-icing operations, and dry-weather discharges from runway maintenance are not required to obtain coverage under an industrial stormwater permit. Those flows may need separate authorization, so decide which authorization applies to each before you treat a result from a mixed outfall as a stormwater result.
Benchmark values and monitoring frequencies sit in the pollutant table of the permit you hold, whether the EPA MSGP or a state general permit. The rule is simple: take each pollutant on your Sector S inventory, find its row in that table, and sample the outfalls that carry only covered stormwater. A pollutant with no benchmark row can still be a SWPPP source you have to control.
Treating fueling areas and aprons for oil and grease
Standard Smart Sponge® is hydrophobic media that attracts oil and binds oil, grease and hydrocarbons into a stable solid. Choose the format by where the water moves:
- Apron and fueling-area inlets: Ultra Urban® Filter inserts are the default. They are custom-fabricated to each catch basin and retrofit existing basins without excavation, pumps or power. Airfield drainage needs high flow rates, which is a point to raise in your site assessment.
- Vaults, channels and trench drains: switch to Smart Pak® or Smart Bags where an insert will not fit.
- Outfalls and sumps: use skimmers or booms where floating oil, fuel and sheen reach the discharge point.
- Larger flows: load bulk media into existing pressure vessels, tanks or vaults. Smart Skid systems add pumps, so they are the one pumped option here.
Where one apron drains to a few basins, treat at those inlets first. Where flows from several areas merge before discharge, start at the outfall. If deicing-season runoff shares the same drainage, include those flows in the site assessment, since they change the flow and the water the media sees.
What sediment controls and oil separators leave behind
As a general matter, sediment and TSS controls are designed for particulates, and oil separators are designed for free oil. Dissolved zinc, copper and lead, and dissolved hydrocarbons and organics, are not what those devices are built to capture. Smart Sponge® HM targets dissolved lead, zinc, copper, arsenic and selenium along with phosphorus, and Smart Sponge® AC targets dissolved hydrocarbons and organic compounds that raise total organic carbon.
Your lab report's dissolved and total split tells you which case you are in. Dissolved vs total metals explains what each result means for treatment. The working rule: if dissolved metals or organics exceed the benchmark while TSS and oil and grease pass, add a dissolved-targeting media downstream of the existing controls. For the broader selection logic, see choosing a stormwater BMP that cuts dissolved pollutant load.
Then test on your own water. Larger applications can add laboratory column testing on a sample from the site, followed by a pilot, before full-scale deployment. Testing indicates how the media performs on that water. Results vary by site, and no test guarantees compliance. When water carries more than one class of pollutant, several media can share one system. A site assessment reviews your contaminants, flows, space and maintenance access. Once inserts are in, insert cleaning schedules explains what sets how often they need service.