Operation | Hydrodynamic Separator
There are 3 distinct models of the Aqua-Swirl® Hydrodynamic Separator (HDS). Each HDS is designed to provide a high level of water quality treatment through the use of a single swirl chamber. Operation begins when stormwater enters the Aqua-Swirl® by means of its tangential inlet pipe thereby inducing a circular (swirl or vortex) flow pattern. The internal area of each swirl chamber represents the effective treatment area of the device where both the capture and retention of sediment, debris and free floating oil can occur. A combination of gravitational and hydrodynamic drag forces results in solids dropping out of the flow. Particles settle and migrate to the center of the swirl chamber floor where velocities are the lowest. The captured (settled) particles are retained in a cone shaped sediment pile at the base of the swirl chamber. We have outlined specific differences between the models below:
The offline Aqua-Swirl® Concentrator configuration uses a separate diversion structure, or weir device located upstream of the unit. The diversion structure is designed to direct only the designed water quality treatment flow through the swirl chamber. Twin or multiple Aqua-Swirl® system configurations can be implemented to allow for higher treatment flow capabilities beyond that of a single unit.
The inline (online) configuration uses an internal bypass (BYP) design to provide full treatment for the most contaminated first flush, while the cleaner peak storm flow is diverted and channeled through the main conveyance pipe.
The BYP design can be compatible with retrofit applications. Local stormwater guidelines should be reviewed to determine whether a BYP system can be used in lieu of an offline water quality treatment unit.
The Aqua-Swirl® XCelerator is a rapid or high velocity stormwater device that has no moving parts and operates on gravity flow or movement of the stormwater runoff entering the structure.
Operation begins when stormwater enters the swirl chamber by means of its tangential inlet pipe thereby inducing a circular (swirl or vortex) flow pattern. The swirl chamber diameter represents the effective treatment area of the device. Both sediment capture and sediment storage is accomplished within the single swirl chamber. A combination of gravitational and hydrodynamic drag forces results in solids dropping out of the flow and migrating to the base of the swirl chamber where velocities are the lowest.
The treated flow exits the Aqua-Swirl® XCelerator behind the arched inner baffle and through an outlet structure positioned at the effluent outlet pipe opening. The outlet structure controls the flow of treated water out of the treatment chamber and is sized to the maximum treatment flow rate (MTFR) of the system. The baffle has a high flow bypass weir which allows flows in excess of the MTFR to spill over it and continue to the outlet structure without passing through the vortex area. Thus, internal bypass flow volumes that exceed the MTFR never co-mingle with the flow volume representative of the effective treatment area.
Aqua-Swirl Trash Capture
The Aqua-Swirl® Trash Capture models is based on the same vortex-type hydrodynamic separation technology which provides for the removal of suspended sediment, trash and free-floating oil using a single cylindrical chamber for both treatment and storage of captured material. The decreasing flow rate in the swirl chamber causes suspended non-buoyant material to fall out of suspension and settle to the bottom of the chamber. The Aqua-Swirl® trash control device incorporates a 4,700 micron (μm, or 4.7 mm) perforated screen. The trash retention screen is affixed to the base of the arched baffle and extends vertically below the baffle. The base of the screen is capped horizontally and attaches to the wall of the swirl chamber to prevent trash material from escaping behind the baffle. Floatables and trash are captured and retained on the inlet (and upstream) side of the arched baffle.
A unique quality of the Aqua-Swirl® trash capture device is its modular design which allows for faster and simpler installation on new construction or retrofit projects for existing storm drainage structures. No external driving head is needed for operation other than that needed to convey stormwater flow according to the site drainage design. The invert of the inlet and outlet pipe of the Aqua-Swirl® is positioned at the same elevation so that the unit can easily be connected directly to the existing storm conveyance drainage system.
Aqua-Swirl Concentrator (BYP) Operation
2733 Kanasita Drive. Suite 111, Chattanooga, TN 37343
Toll Free: 888.344.9044 | Phone: 423.870.8888 | Fax: 423.826.2112
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