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First Defense

First Defense

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

First Defense is a compact, versatile stormwater separator designed to capture and retain sediment, trash, and floatables. Its small footprint makes it ideal for space-constrained or challenging site conditions. Available in multiple configurations, including a High Capacity model with independently verified flow rates, it meets a range of stormwater regulations. First Defense offers maximum site flexibility and can be integrated into treatment trains, making it effective for managing runoff from various impermeable surfaces without compromising treatment performance.

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Additional Information

How It Works

  1. Contaminated stormwater enters the inlet chute tangentially, creating a low-energy vortex flow that directs sediment into the sump while oils/floatables rise to the surface.
  2. Treated water exits through a submerged outlet chute on the opposite side of the vortex flow path.
  3. At higher flows, an integral bypass chute conveys peak flows directly to the outlet, preventing turbulence and washout of captured pollutants.
  4. Floatables are diverted away from the bypass into the treatment chamber through a draw-off port.

Benefits

  • Space-Saving: Fits into standard manholes/chambers for a small footprint.
  • Site Adaptability: Variable configurations accommodate tight spaces, large/multiple pipes, and inlet grates.
  • Pollutant Retention: Low-energy vortex prevents washout of captured pollutants.
  • Easy Installation: Pre-assembled units install like any manhole/chamber.

Applications

  • LID/LEED/SuDS systems
  • Point-of-entry stormwater treatment
  • Space/topography constrained sites
  • Retrofit onto existing storm drains
  • Pretreatment before filters/infiltration/storage

Key Performance Attributes

  • Targets: Coarse/fine particles, trash, floatables
  • Approved flow rates among highest in U.S.
  • Multiple verifications/certifications (NJCAT, NJDEP, ISO, City of Indianapolis, etc.)