The Downstream Defender is the most advanced vortex separator available for the removal of sediment, oil and floatables from stormwater runoff. The Downstream Defender is proven to be more efficient than other structural treatment devices in as little as 1/2 the footprint and is the only separator with internal components proven to prevent pollutant washout.

Applications

• Removal of sediment and TSS
• 100% capture of floatable trash
• Removal of oils and grease from stormwater runoff (meets Class II Oil Collector requirements)
• Stormwater treatment for new developments and redevelopment projects
• Stormwater treatment Municipal/ DOT expansions or improvements for streets, roadways and parking lots
• Pretreatment for infiltration, stormwater detention and stormwater filtration

Advantages

• Most efficient separator available
• Smaller footprint
• Lower capital cost than other devices
• Low system headloss
• Proven to prevent pollutant washout
• Verified through nationally recognized programs
• Easy to maintain. Watch a real clean out on YouTube: http://www.youtube.com/watch?v=M2Gr_UFTys4

The Downstream Defender has internal components designed to advance vortex separation by minimizing turbulence and headloss, increasing efficiency, and preventing washout of stored pollutants.

Watch the animation or read below to see how it works.

Stormwater is introduced tangentially into the side of the vessel, generating a rotating flow that spirals around the outside of the dip plate.

Oils, trash and floatable debris rise to the water surface and are trapped in the oil and floatables storage volume.

As flow continues to spiral down around the dip plate cylinder, low energy vortex motion directs sediment inward along the benching skirt and into the protected sediment storage zone (brown zone).

The benching skirt and center cone redirect the rotating flow up and inward between the center shaft and dip plate cylinder away from the stored sediment. The outlet pipe discharges treated effluent from within the dip plate cylinder ensuring the longest possible residence time.

Advanced vortex separation is provided by extending and stabilizing the flow path while protecting trapped pollutants for a wide range of flow rates.

Frequently asked questions

Q. What are the sizes available? What size do I need? What does it weigh?

We produce 4 standard sizes: 4, 6, 8, and 10 feet. Performance details of each model are outlined in the Downstream Defender flyer. Please inquire for pick weights.

Q. Does the Downstream Defender remove oil and hydrocarbons? Is it an oil collector?

The Downstream Defender has been independently tested and has been shown to meet the requirements required for a Class II oil collector.

Q. The Downstream Defender doesn’t have a screen. Is it an effective trash capture device?

The Downstream Defender uses the principles of flotation and sedimentation to capture all floatable and neutrally buoyant trash.

Q. Can it be modified from the specifications shown in the brochure?

Some dimensions of the Downstream Defender cannot be modified as it relies on certain critical dimensions and minimum pipe sizes in order to function correctly. However, extended sump depths and other dimensional modifications may be available. Please inquire or submit a Request For Proposal to our engineering team and we will work with you to determine the best solution for your application.

Q. Why is the inlet pipe submerged?

To minimize turbulence within the treatment chamber, thus increasing the pollutant capture and retention efficiency.

Q. What size inlet/outlet pipe is acceptable?

Acceptable inlet/outlet pipe sizes vary by model size. Please refer to the sizing chart on the Downstream Defender flyer for acceptable pipe sizes.

Q. Can the Downstream Defender accept two inlet pipes?

In some cases, yes. The inlet pipes connect to the manhole on a tangent, so in some cases multiple inlet pipes cannot be accommodated.

Q. What is maintenance procedure for cleanout? Is confined space entry required? How often is maintenance needed?

No man entry is required. Maintenance is safe and easy with a standard vactor truck. Maintenance consists of removing sediments from the sump and floatable oils, grease, trash and other debris from the floatables capture zone. Watch the maintenance process on YouTube: http://www.youtube.com/watch?v=M2Gr_UFTys4

Q. Why is there no internal bypass?

The standard Downstream Defender models are designed to be “online” units that treat the entire flow, therefore there is no internal bypass. However, the Downstream Defender can be designed “offline” with an upstream bypass diversion structure. The Downstream Defender also has an internally bypassing configuration called the Inline Downstream Defender for the 4-ft and 6-ft models.

Q. Where is the Downstream Defender approved for use?

The Downstream Defender is generally accepted for stormwater treatment or pretreatment in most areas of the United States. Please inquire for specific sizing criteria applicable to your area.

Q. What materials are used to manufacture the Downstream Defender? Are the materials made in USA?

The Downstream Defender is 100% made in the USA. The internal components are rotomolded polyethylene supported by a stainless steel frame. The chamber is a standard concrete manhole.

Q. What sizes are available? How do I know what size is appropriate for my application?

The Downstream Defender is available in 4, 6, 8, 10 and 12-ft diameters. The unit size needed for your specific application depends upon many factors including the level of treatment desired, the target pollutant and peak drainage system flow. Please inquire for more site-specific technical assistance.

Q. What does the Downstream Defender cost?

The price varies slightly with location based on local precast concrete pricing, as well as design criteria such as overall height of the concrete manhole. Please request a proposal on the Inquiry page.

Q. Are Downstream Defenders available everywhere in the US? Where can I buy one?

The Downstream Defender is available worldwide. In the United States, Canada and Mexico, contact Hydro International in Portland, ME or find a local sales rep in your area. For availability in the United Kingdom, please visit our UK website. For all other international locations, please visit our international website.

Q. Where do I get general arrangement drawings and specifications for the Downstream Defender?

General Arrangement drawings and Specifications are available from the Downloads tab.

Q. Where is the pump? Doesn’t the Downstream Defender need a pump because of the submerged inlet?

No pump is needed. Based on simple hydraulics, the water level in the Downstream Defender will fill to the invert of the outlet during the first storm without any assistance required from a pump.

Q. What is removal efficiency of the different size units?

Removal efficiency is dependent upon the particle size and specific gravity of the pollutant, in addition to the flow rate of the stormwater runoff. Please submit a request to our technical team for assistance selecting the appropriate model size.

Q. Does installation of the Downstream Defender require any special equipment or experience?

The installation process of a Downstream Defender is similar to installing a standard manhole. The inlet pipe is grouted in to the manhole chamber while the outlet pipe is connected with a Fernco coupling or a pipe boot. Submit a request for an installation manual from our technical team for additional details.