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 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 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 First Defense stormwater separator provides versatile capture of sediments, trash and floatables that allows engineers to maximize available site space without compromising stormwater treatment level.
First Defense is available in different configurations to comply with stormwater regulations defined by various jurisdictions.
The First Defense reliably treats runoff from impermeable surfaces across a broad range of catchments.
First Defense also operates successfully as part of a management train alongside other proprietary or natural drainage features, for example as treatment before infiltration.
The First Defense® provides space-saving, easy-to-install surface water treatment in standard sized chambers/manholes.
Variable configurations will help you effectively slip First Defense® into a tight spot. It also works well with large pipes, multiple inlet pipes and inlet grates.
The First Defense® 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.
Every First Defense® unit is delivered to site pre-assembled and ready for installation, so installation is as easy as fitting any chamber/manhole.
1. Contaminated stormwater runoff enters the inlet chute from a surface grate and/or inlet pipe. The inlet chute introduces flow into the chamber tangentially to create a low energy vortex flow regime that directs sediment into the sump.
2. Treated stormwater exits through a submerged outlet chute located opposite to the direction of the rotating flow. Enhanced vortex separation is provided by forcing the rotating flow within the vessel to follow the longest path possible rather than directly from inlet to outlet.
3. Higher flows bypass the treatment chamber to prevent turbulence and washout of captured pollutants. An integral bypass chute conveys infrequent peak flows directly to the outlet chute, eliminating the expense of external bypass control structures.
4. Floatables are diverted away from the bypass chute into the treatment chamber through the floatables draw-off port.