CDS – Continuous Deflective Separator

The CDS hydrodynamic separator is a unique hybrid technology that employs swirl concentration and inertial based screening to effectively separate suspended solids, hydrocarbons and trash from stormwater runoff. In a process called, “Continuous Deflective Separation” the power of the incoming flow is harnessed to shear stormwater pollutants off the screen and deflect them to the centre of the separation chamber where they fall to the storage sump or are trapped at the water surface for later removal.

There are over 40,000 CDS installations worldwide with units treating flows from 10 l/s to 5,000 l/s. With this range of capability, the CDS is a premier technology for underground storage and low impact development (LID) pre-treatment as well as treatment of large municipal draining systems.

How The CDS Stormwater Treatment System Works

How it Works

The stormwater enters the CDS through one or more inlet pipes, or through an inlet grate inlet. The stormwater is then directed into the treatment chamber by the inlet flume built onto the inlet bay of the fiberglass internals. Stormwater energy is used to create a swirling vortex inside the swirl chamber. The flow velocities in the swirl chamber continuously shear and deflect all debris off and away from the treatment screen.

The hybrid action of the swirl concentration and indirect screening forces all naturally buoyant and floatables materials to the centre of the screen. The floatables rise to the top of the water surface and are trapped inside the separation cylinder. All, 100% of floatables and naturally buoyant materials larger than the 2.4 mm screen aperture are trapped.

Solids settle out into the separate sediment sump specially designed to capture and retain sediment during high-intensity storm events, eliminating re-suspension of solids. Hydrocarbons are captured underneath the hydrocarbon baffle which shrouds the treatment chamber. An internal diversion weir allows flows greater than the treatment capacity of the unit to by-pass the treatment chamber. Treated stormwater exits the CDS unit via the outlet pipe.

Key Features and Advantages

DESIGN FLEXIBILITY – Can be designed to treat from 10 L/s to 5,000 L/s
SELF-CLEANING SCREEN TECHENOLGY – Indirect screening capability keeps screen from clogging
SITE SPECIFC DESIGN – Completely customizable to operate under various site conditions. Optimized design using hydraulic and grit loading calculations.
INTERNAL BY-PASS – No need for extra structures for most cases.
SUPERIOR FLOATABLE TRAP – Captures 100% of the floatables and neutrally buoyant materials larger than 2.4mm
SEDIMENT ENTRAPMENT – Captured sediment will not re-suspend during high flows.
STRUCUTRE FLEXIBILITY – Can accommodate multiple inlets.
CATCH BASIN – Catch basin configuration available with or without inlet pipe.
MAINTENANCE – Surface access for inspection and cleanout, no confined space entry required.

Approvals

CDS has been verified by some of the most stringent stormwater technology evaluation organizations in North America, including:

Canadian Environmental Technology Verification (ETV)
Ontario Ministry of Environmental and Climate Change (MOECC) – New Environmental Technology Evaluation (NETE) program
Ontario Provincial Standards (OPS) – Approved for roadway applications.
Washington State Department of Ecology
New Jersey Department of Environmental Protection – Recertified as of January 2015

Configuration

The CDS is a versatile oil grit separator which can be designed to treat variety of flows and meet any site-specific constraints. It is available in the following options:

Internal and external peak bypass options
Inline, offline, grate inlet, and drop inlet configurations
Customizable sump and weir height
Non-buoyancy structure

Applications

CDS is commonly used to provide stormwater quality control (trash, debris, sediment and hydrocarbon removal) in numerous applications including:

PARKING LOTS – Commercial, Industrial, and Institutions
RESIDENTIAL – Medium and High-density
INDUSTRIAL YARDS – Maintenance facilities and corporation yards
MUNICIPAL – Roadways, bridges, transit facilities
PRE-TREATMENT – for filtration, detention/infiltration, bioretention, rainwater harvesting systems, and Low Impact Development designs.