Overview 

The Hydro DryScreen® is a next-generation baffle box that captures sediment and screens trash and other solids from stormwater, storing organic materials such as leaf litter dry to prevent nutrients from leaching into surface water runoff between storm events.

Improving on the conventional baffle box design with the inclusion of a patented flow diffusing mechanism, the system is resistant to blocking and blinding, and requires significantly less maintenance than other stormwater treatment systems.

Applications

  • Regions with larger pipes and high peak flows
  • Installations requiring low headloss, such as relatively flat drainage profiles
  • Shallow installations where high groundwater or bedrock present excavation challenges
  • Areas where trash and nutrients in stormwater is particularly problematic

Only Hydro DryScreen®

  • Has a patented flow diffuser that evenly spreads debris, improving performance and reducing the risk of blockage so you can go longer between servicings

Designed for

Coarse particles

High flow

Nutrients

Trash & floatables

Benefits

Prevent nutrient pollution

Hydro DryScreen® stores leaves and organic material dry, rather than in a wet sump, preventing nutrients from leaching into stormwater.

Conventional screening baffle box designs send flow directly from inlet to outlet without slowing down the flow, causing debris to collect in piles and quickly blind some areas while not using other areas; in these boxes the velocity of direct flows are more likely to tear apart organic matter, causing it to fall into the wet sump and generate dissolved nitrogen and phosphorus. 

Improve sedimentation performance

When the flow path is redirected by the patented flow diffuser it increases the time during which total suspended solids (TSS) remain in the Hydro DryScreen®, encouraging sedimentation of these suspended particles.

Reduce blinding and ensure optimal effectiveness

The flow diffuser distributes flow and debris evenly across the entire screen, reducing the risk of blinding and ensuring that the system continues to operate at its full design effectiveness.

Cut maintenance

The even flow distribution reduces the risk of ragging and blockage, and a larger screenings storage capacity than conventional baffle boxes means that the Hydro DryScreen® requires significantly less maintenance.

Adapt to a variety of site conditions

The Hydro DryScreen® works well with high peak flows, large pipes, shallow sites or anywhere where low headloss must be accommodated. The elevation can be adjusted to account for tail water or base flows.

How it works

Baffle box sedimentation is a relatively simple pollutant removal process based on the principle of slowing the velocity of flow through a pipe in order to allow solids to settle out of the flow stream. However, the inclusion of the patented flow diffuser means that the Hydro DryScreen® operates more reliably and at optimal effectiveness. 

  1. As stormwater enters the Hydro DryScreen® chamber, the flow is diffused and slowed by the flow diffuser.
  2. Gross solids are conveyed around the diffuser and captured on the horizontal screen, where they are held dry. 
  3. As the flow encounters the first baffle wall, the velocity slows again, allowing suspended particles to settle.
  4. Other solids in the flow stream strike the baffle wall and settle to the sump, where further movement is impeded by the presence of the baffle.
  5. Flow continues through the next two baffle chambers, where smaller particles settle.

 

Technical information

Dimensions

  • 4 x 8 ft / 1.2 x 2.4 m
  • 6 x 12 ft / 1.8 x 3.7 m
  • 8 x 14 ft / 2.4 x 4.3 m
  • 10 x 16 ft / 3.0 x 4.9 m
  • 12 x 20 ft / 3.7 x 6.1 m

Treatment capacity

  • Up to 162 cfs / 4,500 l/s

Typical treatment flow rate

  • 11 - 80 cfs / 303 - 2,200 l/s

Screenings storage capacity

Up to 35 yd3 / 26.8 m3

Sediment storage capacity

Up to 35.4 yd3 / 27.1 m3