First Defense® High Capacity

Versatile Stormwater Separator

Capture and retain stormwater sediment, trash and floatables in a unit that saves site space and adapts to smaller or logistically difficult site locations.

The First Defense® High Capacity (FDHC) is a versatile stormwater separator with the highest approved flow rates in the United States, enabling engineers and contractors to save site space and projects costs by using the smallest possible footprint. It also works with single and multiple inlet pipes and inlet grates.  It is easily maintained from the surface by standard vacuum tanker.

Designed with site flexibility in mind, the FDHC stormwater separator provides versatile capture of sediments, trash and floatables that allows engineers to maximize available site space without compromising stormwater treatment level.

FDHC works easily with single or multiple inlet pipes and inlet grates, and is independently tested, verified and approved.

Targeted Pollutants

  • Coarse particles
  • Fine particles
  • Trash
  • Floatables


FDHC reliably treats runoff from impermeable surfaces across a broad range of catchments.

FDHC also operates successfully as part of a management train alongside other proprietary or natural drainage features, for example as treatment before infiltration.

  • As part of LID or LEED systems and Sustainable Drainage Systems (SuDS).
  • Stormwater treatment at the point of entry into the drainage line.
  • Sites constrained by space, topography or drainage profiles with limited slope and depth of cover.
  • Retrofit installations where stormwater treatment is placed on or tied into an existing storm drain system.
  • Pretreatment for filters, infiltration and storage.


Cuts Footprint Size and Cuts Costs
The FDHC provides space-saving, easy-to-install surface water treatment in standard sized chambers/manholes.


Adapts to Site Limitations
Variable configurations will help you effectively slip FDHC into a tight spot. It also works well with large pipes, multiple inlet pipes and inlet grates.

Prevents Washout
The FDHC retains the pollutants it captures. The low-energy vortex separation of the First Defense® eliminates excessive agitation of captured pollutants ensuring that these pollutants are not washed out during subsequent rainfall events.


Saves Installation Time
Every FDHC unit is delivered to site pre-assembled and ready for installation – so installation is as easy as fitting any chamber/manhole.

$1000 Special Offer

Our products partner, Hydro International, is offering our contractor friends a great offer, automatically save $1000 off your next water quality structure by using a First Defense® High Capacity hydrodynamic separator (FDHC) instead of an alternative separator. If you think the FDHC is a separator that you can use on one of your projects, take advantage now of the $1000 savings by contacting us today.