Manufacturer: Environment 21

Product: V2B1

NOTE: The above models have a HLR ranging from 9.11 to 9.18.

The V2B1 Stormwater Treatment system provides primary treatment of stormwater using locally available precast manholes and pipe. The tangential inlet pipe provides optimum swirl distribution for sedimentation separation. 3-5 foot sump provides ample sediment storage. Treated surface water enters a floatables chamber where floating oil and organic debris are trapped by a baffle wall. An underflow opening in the bottom of the baffle wall directs flow to the system outlet pipe.

Untreated surface water travels through the center pipe to the second chamber where the floatable debris and hydrocarbons are trapped via a precast baffle wall with site specific flow openings located below the water surface elevation.

In addition to a standard online system the V2B1 can also be configured with an internal high flow bypass that either can completely bypass the swirl and floatables chamber or bypass the swirl chamber also. Allowing the design engineer to decrease the size of the system required for the project, thereby decreasing construction cost.

All V2B1 Stormwater Treatment Systems are manufactured locally to the project site by approved manufacturers with a proven record of quality in the precast concrete market.

V2B1 Working Principle

/ Phase 1: Dry weather level.
The V2B1 utilizes two round structures of varying diameters (depths for both structures are typically equal). The two structures are connected by a series of three pipes.
/ Phase 2: First flush, two month storm.
The first chamber (1) is designed to separate the contaminated particulate (brown) from the drain water. The inlet pipe is offset to introduce the influent tangentially into the first structure. Floating pollutants (red) such as petroleum, litter and organics are pushed through the center pipe into the floatable containment chamber (2).
/ Phase 3: Rising storm flow intensity.
As the volume of flow through the inlet pipe increases, a swirl begins to develop in the first chamber (1). Liquid levels in the structures correspond with the intensity of the storm event.
/ Phase 4: Residual floatable transport.
Residual floatables, which were not transferred to the floatable containment chamber (2) during the initial storm flow, rise to the point of overcoming the vertical portion of the bottom pipe called the "Coriolus Intake". The residuals are then drawn into the middle of swirl-chamber (1) and delivered to the floatable containment chamber (2) in a low-flow circumstance.
/ Phase 5: Peak flow, floatable chamber bypass.
The corner stone of the V2B1 hydraulic design is the top pipe connecting the vortex separator to the outlet chamber (3). This "shunt", under peak storm design, carries the majority of flow directly to the outlet chamber (3). By discouraging peak flows from passing under the baffle wall, any Venturi effect on or discharge of captured pollutants from the V2B1 system are minimized.
/ Phase 6: Dry weather pump-out.
The frequency of pump-out is based on the site loading, periodic monitoring and measurements of captured pollutant levels in the swirl-chamber (1). If the V2B1 is maintained on a regular schedule, the only chamber that requires pumping is the swirl-chamber (1). This will remove both solid and floating pollutants from the system.

The following chart was taken from a precaster’s website. As you can see, the flows are quite different from those shown on the NJCAT testing chart above. The HLR is quite different as well.

V2B1
Model / approx. flowrate
[cfs] / D1
[ft.] / D2
[ft.] / Pipe
P1 / Pipe
P2 / Pipe
P3 / approx.
height
[ft.]
3 / 2,8 / 4 / 4 / * / * / * / 8
4 / 4,3 / 5 / 4 / * / * / * / 8
6 / 6,2 / 6 / 5 / * / * / * / 8
9 / 8,5 / 7 / 6 / * / * / * / 8
11 / 11,1 / 8 / 6 / * / * / * / 10
17 / 17,4 / 10 / 8 / * / * / * / 10
25 / 25,2 / 12 / 10 / * / * / * / 10
V2B1 Model / Approx Flowrate (cfs) / HLR
3 / 2.8 / 39.03
4 / 4.3 / 49.15
6 / 6.2 / 58.08
9 / 8.5 / 47.88
11 / 11.1 / 63.43
17 / 17.4 / 60.63
25 / 25.2 / 69.24

In Addition, on their drawings for the Online System they show a sizing table with minimum/maximum treatment flows.

V2B1 Model / Treatment Flow / Minimum Treatment HLR / Maximum Treatment HLR
3 / 0-1 / 0 / 13.94
4 / 1-2 / 11.43 / 22.86
6 / 2-3 / 18.74 / 22.86
9 / 3-5 / 23.17 / 28.11
11 / 5-7 / 28.57 / 40
17 / 7-10 / 24.39 / 34.85
25 / 10-13 / 27.47 / 35.72