The Storm King® is an advanced hydrodynamic vortex separator and screen that delivers exceptional removal of total suspended solids (TSS), biological oxygen demand (BOD), gross solids and floatables at combined sewer overflow (CSO) sites, helping engineers and operators to improve wastewater management systems and prevent damaging pollutants from reaching the environment.

The Storm King® screens and removes 100% of solids, floatables and neutrally buoyant material larger than 6 mm, meets primary treatment equivalency for sediment and BOD and can also be used as a contact vessel for disinfection. A small-footprint, low-headloss solution, it is non-powered, self-activating and self-cleaning, making it ideal for low-maintenance remote and satellite CSO sites.

Storm King® has been shown to reduce project costs by up to 50% when compared to conventional technologies.


  • Floatables control, sedimentation and disinfection of CSOs
  • New satellite CSO facilities and upgrades to existing CSO facilities
  • Treatment of excess wet-weather flows at WWTPs
  • Stormwater treatment at centralized stormwater treatment plants
  • Combined sedimentation, screening and disinfection

You can watch a brief video demonstrating the Storm King® here. Download the Storm King®  brochure here.

Aerial View of Storm King System

Designed for

Coarse particles

High flow

Trash & floatables


Get superior CSO treatment

The Storm King® delivers 100% removal in two directions of gross solids, floatables and neutrally buoyant material larger than 6 mm, and achieves 95% removal of TSS and BOD - equivalent to primary treatment.

Combine screening, sedimentation and disinfection

The Storm King® incorporates both a screen and a hydrodynamic separator to ensure exceptional removal of CSO pollutants, and trials conducted in the USA at Columbus, GA and Saco, ME show that the unit can also be used to provide disinfection in 30% of the area normally required for conventional disinfection technologies - enabling the system to provide three treatment functions in a single unit. 

Reduce project costs

The Storm King® is a small-footprint, non-powered, low-maintenance unit with low capital and O&M costs, and offers up to 50% project cost savings when compared with conventional technologies such as micro-strainers.

Cut maintenance

With no moving parts, no power requirements and self-cleansing components, the Storm King® is a low-maintenance CSO treatment and wastewater management solution.

How it works
  1. Storm-King-How-It-WorksFlow is introduced tangentially into the side of the Storm King®, causing the contents to rotate slowly about the vertical axis (blue arrow).

  2. The flow spirals down the perimeter, allowing the solids to settle out. This process is aided by rotary forces, shear forces and drag forces at the boundary layer on the wall and base of the vessel.

  3. The internal components direct the main flow away from the perimeter and back up the middle of the vessel as a broad spiraling column, rotating at a slower velocity than the outer downward flow (red arrow). By the time the flow reaches the top of the vessel, it is virtually free of settleable solids and is discharged to the outlet channel. Prior to discharge, the overflow passes through the swirl cleanse screen.

  4. The swirl cleanse screen captures all floatables and neutrally buoyant material greater than 6 mm. The air-regulated siphon provides an effective backwash mechanism to prevent the screen from blinding.

  5. The collected solids and floatables are then discharged by gravity or pumped out from the base of the unit to the sanitary sewer.



Technical information

Pollutant removal rates

  • Floatables, gross solids, neutrally buoyant material: 100% of 6 mm in two directions

  • High rate disinfection in less than 8 minutes

  • Grit and sediment: 95% removal of grit 106 micron and larger can be provided; different size systems can be provided for different levels of grit removal performance.