The CDS is a swirl concentrator hybrid technology that provides patented continuous deflective separation – a combination of swirl concentration and patented indirect screening to screen, separate and trap debris, sediment, and hydrocarbons from stormwater runoff. The indirect screening capability of the system allows for 100% removal of floatables and neutrally buoyant material debris 2.4mm or larger, without binding. CDS retains all captured pollutants, even at high flow rates, and provides easy access for maintenance.
CDS is used to meet trash Total Maximum Daily Load (TMDL) requirements, for stormwater quality control, inlet and outlet pollution control, and as pretreatment for filtration, detention/infiltration, bioretention, rainwater harvesting systems, and Low Impact Development designs.
How CDS Treats Stormwater
- Stormwater enters the CDS through one or multiple inlets and/or a grate inlet.
- The inlet flume guides the treatment flow into the separation chamber where water velocities within the chamber create a swirling vortex.
- Water velocities in the swirl chamber continually shear debris off the patented treatment screen, making it the only non-blocking screening technology available in a hydrodynamic separation system.
- The combination of swirl concentration and indirect screening force floatables and solids to the center of the separation chamber trapping 100% of floatables and neutrally buoyant debris larger than the screen aperture.
- Sediment settles into an isolated sump while floatables and neutrally buoyant pollutants are captured in the separation cylinder. All pollutants remain in these sections of the unit until they are removed during maintenance.
- Stormwater then moves under the hydrocarbon baffle, and the treated water exits the system. The baffle acts as a wall for hydrocarbon containment. It contains previously captured hydrocarbons and prevents the agitation of hydrocarbons when high-flows spill over the diversion weir.
- During high-intensity events, the internal diversion weir directs a portion of flows greater than the design storm around the treatment chamber and over an internal bypass weir.
- Treated stormwater exits the CDS via the outlet pipe.
CDS Features and Benefits
|1. Patented screen technology
||1. Captures and retains 100% of floatables and neutrally buoyant debris 2.4mm or larger
|2. Self-cleaning screen
2. Ease of maintenance
|3. Isolated storage sump eliminates scour potential
||3. Excellent pollutant retention
|4. Internal bypass
||4. Eliminates the need for additional structures
|5. Multiple pipe inlets and 90-180º angles
||5. Design flexibility
|6. Numerous regulatory approvals
||6. Proven performance
- Inline, offline, grate inlet, and drop inlet configurations available
- Internal and external peak bypass options available
CDS has been verified by some of the most stringent stormwater technology evaluation organizations in North America, including:
- Washington State Department of Ecology
- New Jersey Department of Environmental Protection
CDS is commonly used in the following stormwater applications:
- Stormwater quality control – trash, debris, sediment, and hydrocarbon removal
- Urban retrofit and redevelopment
- Inlet and outlet protection
- Pretreatment for filtration, detention/infiltration, bioretention, rainwater harvesting systems, and Low Impact Development designs.
- Maintaining a CDS is a simple process that can be accomplished in less than 30 minutes for most installations using a vacuum truck, with no requirement to enter the unit.
Contech has created a network of Certified Maintenance Providers
to provide maintenance on stormwater BMP’s.