A Downstream Defender® Select removing pollutants before a pond
Stormwater treatment

Downstream Defender Select

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Customise the capture and retention of sediment, oils and floatables from stormwater runoff over a wide range of flows in a small footprint.

The Downstream Defender® Select is the new generation of hydrodynamic vortex separator for treatment of stormwater runoff to protect the environment and meet water quality requirements.  Engineers can customise the performance of the unit to meet specific stormwater quality objectives through model selection and other additional options.  An extended range of chamber sizes allows engineers to tailor their drainage designs to meet specific pollutant removal standards.

The Downstream Defender® Select also offers easier installation with much more flexibility of pipe sizes and connections and can accept up to three inlets.

Design and customise your own Downstream Defender® Select. Log in or register for the free tool: hydro-int.design

Mitigation indices for The SuDS Manual (CIRIA C753) Simple Index Approach (SIA) are listed in the Technical Information section below.

The Downstream Defender® Select separator is the new generation of hydrodynamic vortex separator for treatment of stormwater runoff to protect the environment and meet water quality requirements. Its customisable performance and an extended range of chamber sizes allows engineers to tailor their drainage designs to meet specific pollutant removal standards.

The Downstream Defender® Select can accept a range of inlet pipe sizes and up to three inlets, removing the need for difficult pipe connections, couplings or additional chambers.

Maintenance can be optimised and inspection visits reduced by adding Hydro-Logic® Smart Monitoring, which will generate automated alerts when the units requires emptying.

Watch the video overview of the new Downstream Defender® Select.

Targeted Pollutants

  • Fine particles
  • Floatable debris
  • Liquid and sediment bound hydrocarbons
  • Sediment bound heavy metals
  • Sediment bound nutrients

Applications

The Downstream Defender® Select reliably treats runoff from any impermeable surfaces

  • Highways
  • Car parks
  • Industrial areas
  • Pre-treatment for natural features such as swales, ponds and detention basins.
  • For use with other natural Sustainable Drainage Systems (SuDS) treatment to meet required performance standards.
  • Retrofit
  • As part of SuDS, Water Sensitive Urban Design (WSUD), LID or LEED systems.
  • Areas where high solids and trash/litter capture are a must.
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Customise performance to suit site stormwater quality objectives 

Engineers can meet stormwater quality objectives with customisable performance and the ability to work alongside other treatment solutions such as ponds, swales and constructed wetlands.


Save costs with more specific sizing for performance 

The Downstream Defender® Select is offered in an extended range of chamber sizes helping engineers match flow rates and removal rates more cost-effectively.


Save costs with improved connectivity

The Downstream Defender® Select can accept up to three inlets and a wider range of connecting pipe sizes, helping to make design and installation on site easier and cheaper.

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Reduce maintenance costs by adding automated maintenance alerts

The addition of Hydro-Logic® Smart Maintenance will deliver automated maintenance alerts, helping to ensure that maintenance is carried out and is cost-effective.  This can help with SuDS maintenance plans and also lessen risk and costs by reducing the need for inspection visits for units installed alongside roads or rail tracks.


Ensure retention of hydrocarbons, even at very high flow rates

The option of storing oils/hydrocarbons as solids can be added as an option, providing increased retention, even at very high flow rates.  

Note: This option is available for the Advanced Vortex and Vortex Plus models only.


Reduce the need for heavy plant

The Downstream Defender® Select is available in a plastic chamber, ideal for sites where access for heavy plant may be restricted or where fast installation is required.

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  1. Stormwater is introduced into the side of the chamber via the inlet chute, generating a rotating flow.
  2. Oils litter and floatable debris rise to the water surface and are retained in the floatables storage volume. If the enhanced oil retention option is used, specialist media absorbs and retains oils/hydrocarbons, preventing washout. 
  3. As the flow continues to spiral down the chamber, low energy vortex motion directs sediment inward along the benching skirt and into the protected sediment storage zone.
  4. The flow then rotates back up the chamber and is discharged via the outlet hood.

 

Downstream Defender Select flow path image

Downstream Defender® Select and the Simple Index Approach (SIA)

The Simple Index Approach outlined in CIRIA C753 The SuDS Manual is a water quality design method for sites with a low to medium risk pollution hazard level.  Sites with a high risk pollution hazard level should consider a more precautionary approach.

The approach assigns pollution hazard indices to the given land use for three pollutant groups, total suspended solids (TSS), metals and hydrocarbons.  SuDS components are then selected until their combined pollution mitigation index score is greater than the pollution hazard index for each pollutant group.

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Downstream Defender Select Mitigation Indices for the Simple Index Approach

Customisation of the Downstream Defender® Select

The patented internals of the Downstream Defender® Select provide drainage design engineers with the ability to customise the performance to meet specific water quality objectives, such as the Simple Index Approach (SIA).  Engineers can select from three models, depending on the level of treatment required.

Advanced Vortex

Our recommended model which provides sediments, litter and oil removal with enhanced sediment retention up to four times the treatment flow rate.

Key performance

  • Coarse and fine sediments, retained up to 4 times the treatment flow rate.
  • Litter, debris
  • Liquid hydrocarbons (oils), plus option for enhanced retention.
  • Sediment bound metals
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Vortex Plus

Provides sediments, litter and hydrocarbon removal, with sediments retained at up to two times the treatment flow rate.

Key performance

  • Coarse and fine sediments, retained up to 2 times the treatment flow rate.
  • Litter, debris
  • Liquid hydrocarbons (oils), plus option for enhanced retention.
  • Sediment bound metals
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Vortex 

A simpler model providing removal of sediments, with retention up to two times the treatment flow rate.

Key performance

  • Coarse and fine sediments, retained up to 2 times the treatment flow rate.
  • Sediment bound metals
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Chamber sizes

•    1.0 m
•    1.2 m
•    1.5 m
•    1.8 m
•    2.1 m
•    2.4 m
•    3.0 m
 

> Request a UK 3D model of the Downstream Defender® Select for use with UK Building Information Modelling (BIM)

  • Downstream Defender® Select with collected sediments and floating pollutants
  • Downstream Defender® Select UK installation
  • Downstream Defender® Select three inlet option
  • Downstream Defender® Select UK installation
  • Downstream Defender® Select working with Stormbloc® Optimum, Hydro-Brake® Optimum and Up-Flo™ Filter
  • Downstream Defender® Select UK installation
  • Downstream Defender® Select pollutant removal by vacuum tanker hose
Q

How do I find out which Downstream Defender® Select I need?

A

The easiest way is to use our online design tool (at hydro-int.design) which will take you through a two-step process to size and then refine your Downstream Defender® Select to best meet your site requirements. 

Our expert technical team is also on hand to help you find the perfect fit for your site.  If you would like assistance from the team, please call 01275 337937 or email stormwater@hydro-int.com

Q

What pipe sizes can the Downstream Defender® Select connect to?

A

Each chamber size can be connected to a range of pipe sizes. Log in to our free design tool (hydro-int.design) and you can create your own Downstream Defender® Select design and select available pipe sizes for each chamber size.

If a pipe size isn’t available on the tool, please contact us as we may be able to design a bespoke unit for you – stormwater@hydro-int.com

Q

How many outlets can the Downstream Defender® Select have?

A

The Downstream Defender® Select can only have one outlet, but it can accommodate up to three inlets. The outlet angle is adjustable from 90o-270o.

Q

How will I know when my Downstream Defender® Select needs emptying?

A

The easiest and most cost-effective way is to include or add Hydro-Logic® Smart Maintenance. The ATEX certified data logger and sensors will monitor the sediment and water level in the chamber and will automatically generate an alert via SMS or email when the unit requires emptying.

If you don’t have Hydro-Logic® Smart Maintenance in the unit, undertaking inspections over the first year of installation enable a maintenance plan to be made.

Q

Where in the network should I position a Downstream Defender® Select?

A

Ideally, the Downstream Defender® Select should be positioned as close to the source as possible.  Locating it upstream of any storage structure will also provide protection against reduced storage capacity caused by fine silts and grits settling out in the structure.

Q

What maintenance is required for a Downstream Defender Select?

A

Maintenance is straight-forward and done from the surface; no confined space entry is required.  A standard vacuum tanker will be able to remove hydrocarbons (oils), floatables and litter from the surface of the water, and sediments from the sump.

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