Figure 1. AquaShield
TM
Bio-Filter
TM
System and its five design elements
Step 2: Pretreatment
The water quality treatment flow enters the Pretreatment Chamber where coarse
sediment and oil are captured and retained by principles associated with
hydrodynamic vortex separation, such as that incorporated into the design of the
field proven Aqua-Swirl
®
Stormwater Treatment System. Water enters the
Pretreatment Chamber by a tangential inlet between the Trash Shelf and
Pretreatment Chamber. This inlet sets up the swirling flow motion forcing coarse
sediment to fall out of suspension and accumulate at the base of the chamber.
Any floatables and oil will be retained by the arched baffle positioned on the
outlet side of the chamber. Water exits the Pretreatment Chamber underneath
the arched baffle and through a horizontal opening that extends along the width
of the chamber wall. Water then enters the Biofiltration Chamber.
Step 3. Biofiltration
The water quality treatment flow is distributed across the entire top of the
Biofiltration Chamber via a flow distribution channel that extends entirely along
the outer edge of the chamber. The distribution channel also dissipates the water
flow’s energy to avoid disturbing the engineered soil biomedia and tree. Water
then flows downward driven by gravity flow through the biomedia and plant root
ball to remove fine sediment, heavy metals, residual oil and phosphorus. Next,
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