The Nutrient Separating Baffle Box (NSBB) is an advanced vault treatment system for storm water runoff. Its patented screen system is designed to capture and store debris in a dry state to minimize nutrient leaching and allow for easy servicing. The NSBB’s triple chamber design affords high TSS removal over a wide range of particle sizes, while patented deflectors ensure no sediment scouring occurs during high flows. This allows for on-line installation without the need for separate diversion structures. The NSBB is a widely accepted storm water treatment BMP among developers, civil engineers and municipalities nationwide.




  • Retrofits existing watersheds
  • Patented screens maximize storage and prevent debris loss
  • Easy vacuum truck servicing
  • Dry state storage separates debris and trash from water and sediment
  • Will not go septic between storms
  • Captures thousands of pounds of debris, sediment and nutrients
  • Pretreatment for rainwater harvesting and detention areas
  • Meets requirements for full trash capture TMDL programs

NSBB removal efficiencies up to:*

  • 20% Nitrogen
  • 19% Phosphorous
  • 90% TSS

*Varies based on sizing & site conditions

LEED Credit Eligible:

6.2             Storm Water Design / Quality Control


  • Low pick weights: comprised of multiple sections
  • Fast set: pre-installed internal components (optional)
  • Minimal excavation required


  • Runoff filters through the screen, leaving behind pollutants while hydrocarbons collect in front of the skimmer.
  • Patented turbulence deflectors prevent sediment from becoming resuspended by settling in lower chambers.
  • Nutrient pollutant load is not lost due to static water and will not be flushed out during the next storm event.
  • Separating organic matter from the static water prevents bacterial buildup.


  • Easy maintenance access via top hatches / manholes without need for confined space entry.
  • Hinged screens allow for full vacuum access to inner basket and lower sediment chambers.
  • After cleaning sediment chambers, close and secure bottom screen doors to prevent debris loss.


The Nutrient Separating Baffle Box is a multi-stage, self contained treatment system. Each subsequent component within the system protects prior stages from clogging issues or failures. These stages include filtration, hydrodynamic separation and hydrocarbon absorption.

  • Filtration is provided by a rectangular screen system which is suspended above the static water level. The screen has a storage capacity of several cubic yards depending on the model and a primary function to capture gross solids such as trash and debris.
  • Hydrodynamic separation is facilitated by three settling chambers which work to target smaller sediments and particulate metals.
  • Patented screen system prevents debris loss and nutrient leaching. No need to service after each storm event with dry state storage as compared to competing treatment systems.

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