PR Aqua Supplies Ltd.

Aquaculture and Water Treatment Specialists

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Swirl Separators

Swirl Separator

The more quickly solids are removed from your system, the less time they have to break down and release nutrients and toxins into your culture water. Attaching a swirl separator to your culture tank bottom drain, or to a series of them, provides a good first step in solids removal and reduces the solids-loading to downstream treatment equipment. Ideally the culture tanks are fitted with dual drains (a side outlet in addition to the bottom drain) so the swirl separator is only receiving a fraction of the tank effluent where settleable solids have been pre-concentrated by the tank.

The PR Aqua Swirl Separator is a proven technology that is effective at removing aquaculture waste solids (e.g. uneaten feed and fish feces) over a range of hydraulic loading rates. Where lower hydraulic loading rates are acceptable, PR Aqua Radial Flow Separators may also be considered for improved solids removal efficiency.

Solids Removal Tech Info »

How It Works

Swirl separators concentrate solids based on the “Tea Cup Effect.” Culture tank effluent is introduced into the unit tangentially, creating rotational flow. As the swirling flow rises towards the outlet located near the top of the vessel, solids separate towards the center where velocities are lower, and eventually accumulate in the conical bottom. The clear water leaves the vessel by the overflow weir and the accumulated solids are periodically flushed from the bottom of the cone.


  • Effectively separates waste solids from culture water
  • Induced swirling action minimizes short-circuiting through the vessel
  • Non-turbulent flow minimizes degradation of particles
  • Minimal water use during flushing operation
  • Ability to time flushes based on high solids-loading periods (i.e. just after feeding) minimizing the contact time of solids in the process water
  • Allows for visual monitoring of waste prior to flushing, providing valuable feedback on feeding practices.


  • No moving parts
  • Durable FRP construction
  • Sized for a variety of flow rates
  • May be dedicated to an individual tank bottom drain or may collect wastes from a series of tanks
  • Solids can be purged using a standpipe (standard), manual valve, or timer-controlled valve
  • White gel coat interior allows solid wastes to be easily seen by operators

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