Downstream Defender® System

Hydro International Ltd


To assess the requirements for the Downstream Defender® system as manufactured by Hydro International Ltd.

It is applicable to a vortex separator with a maximum diameter of 3.0 m and maximum treatment flow rate of 190 l/s.

It is not applicable to removal of floating debris or hydrocarbons.


The Downstream Defender® system is a vortex separator designed to utilise the principles of swirl-enhanced gravity separation to remove Total Suspended Solids (TSS), litter and hydrocarbons from storm water runoff.

Depending on the unit size and application, there are two different manufacturing methods for the internal components and two different configuration options available. 

Full details can be found in the Assessment Schedule opposite.

Approval period

19th March 2018 - 19th March 2023

Click on certificate to enlarge

View Assessment Schedule