Contech Engineered Solutions -The Cascade Separator® Hydrodynamic Stormwater Treatment


The Cascade Separator® is the latest innovation in hydrodynamic separation from Contech. The Cascade uses advanced sediment capture technology to provide the highest sediment removal efficiency of any Contech HDS product.

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The Cascade Separator® Hydrodynamic Stormwater Treatment

The Cascade Separator® is the latest innovation in hydrodynamic separation from Contech. The Cascade uses advanced sediment capture technology to provide the highest sediment removal efficiency of any Contech HDS product.

The Cascade Separator® - Advanced Sediment Capture Technology

The Cascade Separator is the newest innovation in stormwater treatment from Contech. The Cascade Separator was developed by Contech’s stormwater experts using advanced modeling tools and Contech’s industry leading stormwater laboratory.

This innovative hydrodynamic separator excels at sediment capture and retention while also removing hydrocarbons, trash, and debris from stormwater runoff. What makes the Cascade Separator unique is the use of opposing vortices that enhance particle settling and a unique skirt design that allows for sediment transport into the sump while reducing turbulence and resuspension of previously captured material. These two factors allow the Cascade Separator to treat high flow rates in a small footprint, resulting in an efficient and economical solution for any site.

How the Cascade Separator Works
  • Stormwater enters the Cascade Separator through one or multiple inlets and/or a grate inlet.
  • As water enters the unit, it impacts the center cylinder and is directed to two separate flumes.
  • Water traveling through the opposing flumes enters the center chamber where vortices rotate in opposite directions and facilitate enhanced particle settling.
  • As water swirls downward sediment settles into the sump and treated water exits through the outlet window and exits the system.
  • When flows exceed the capacity of the flumes, the excess water flows over the flumes and exits the system without re-suspending or washing out previously captured pollutants.
  • The system incorporates a partially perforated slanted skirt that equalizes the pressure between the storage and treatment zone while reducing the potential for scour. The skirt also allows transport of sediment and debris into the sump zone which improves ease of maintenance since all captured material can be removed through the center cylinder.
Cascade Separator Features and Benefits


Unique skirt design & opposing vortices

Inlet area accepts wide range of inlet pipe angles

Accepts multiple inlet pipes

Grate inlet option

Internal bypass

Clear access to sump and stored pollutants


Superior TSS removal; reduced system size and costs

Design and installation flexibility

Eliminates the need for separate junction structure

Eliminates the need for a separate grate inlet structure

Eliminates the need for a separate bypass structure

Fast, easy maintenance

Select Cascade Separator Approvals
  • New Jersey Department of Environmental Protection (NJDEP)
Cascade Separator Configurations
  • Inline, offline, grate inlet, and drop inlet configurations available
Cascade Separator Maintenance
  • Cascade provides unobstructed access to stored pollutants, making it easy to maintain using a vacuum truck, with no requirement to enter the unit.
  • Contech has a network of Certified Maintenance Providers to provide maintenance on Cascade and other stormwater BMP’s.

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Pretreatment to Storage

Our hydrodynamic separators are frequently installed upstream of detention and infiltration systems as pretreatment devices. By capturing the majority of sediment, hydrocarbons and trash and debris upstream of the storage system, maintenance becomes much easier as material is congregated into a smaller device with clear access for cleanout. Additionally, by utilizing pretreatment upstream of infiltration systems, sediment that would have clogged the stone voids in the storage envelope surrounding the storage chamber can be captured before entering the storage system thus extending the longevity of the entire system.

Hydrodynamic Separation for Water Quality

Our hydrodynamic separation products (including the CDS, Cascade Separator, SciCloneX, Vortechs, and Stormceptor Systems) are reliable, easy to install, and offer high-performance, proven, stormwater pollutant removal. The systems are widely accepted for effective solids removal and can be designed to achieve your site treatment goals - including TMDL requirements for TSS and trash.

High Volume Applications

Designing, manufacturing and installing high-volume stormwater detention and treatment systems requires expert engineering, planning, and logistical support to manage costs and keep the project on schedule and under budget. When you need a proven, large scale stormwater management system, “Go Big” with Contech.

Pretreatment for Rainwater Harvesting

Our hydrodynamic separation products are ideal solutions for preatreatment to rainwater harvesting. Not only do they improve the overall water quality, they also provide protect the pumps and controls from being overburdened with material that could clog and damage the mechanical system.