Water & Wastewater Asia March/April 2019

40 | INSIGHT
It’s in the Mix: Rotamix ® Mixing Systems
Improve Process Performance
What sets Rotamix apart from the rest is an absence of moving parts in its unique mixing system,
which creates an even distribution of mixing energy. How does it work?
As biogas production capacity
continues to increase, Vaughan
Rotamix ® stands ready to provide
reliable, efficient hydraulic mixing to
maximize biogas production from anaerobic
digestion. In addition to digesters, Rotamix is
the solution for mixing all tanks in the solids
handling process. Unlike most other means
of tank mixing, which have mechanical
components in the process, Rotamix has no
moving parts in the tank, ensuring maximum
performance and minimal maintenance
requirements.
THE SYSTEM
Vaughan Rotamix is an engineered system
of floor and wall mounted nozzles with flow
supplied by a Vaughan Chopper Pump ® .
The nozzles provide evenly distributed
flow throughout the tank volume, ensuring
complete mixing of the tank contents, while
the Vaughan Chopper Pump continually
conditions the digester contents, while
providing industry-leading efficiency. This
combination results in lower operating costs
A Rotamix 20-metre cone, with arrows to show
how it moves
than conventional draft tubes or mixers,
with a more efficient breakdown of organic
solids and increased biogas production. For
smaller applications, like Fats, Oils, & Grease
(FOG) tanks, Rotamix also offers externallymounted
nozzles which minimise piping and
maximise mixing volume.
THE PROCESS
Rotamix incorporates several basic
principles of physics and hydraulics,
including uniform field of flow, vortical
field of flow, induced flow and surface
contact. Combined together, this unique
mixing system optimises solids and bacteria
contact while creating an even distribution
of mixing energy. Dual-Zone Mixing ensures
even mixing velocity across the entire crosssection
of the tank, which produces an
even flow field that creates a homogenous
volume, ensuring an even distribution of
solids and constant temperature. This
improves digester performance and prevents
settled solids from reducing process
volume.
Each Rotamix design is
unique, varying based on
many factors including sludge
rheology, tank geometry,
and process considerations.
Vaughan uses state-of-theart
Computational Fluid
Dynamics (CFD) modeling to
design each system and can
accurately model not just
the tank geometry, but also
piping and other obstructions
to ensure proper mixing.
A Rotamix nozzle
FOAMBUSTER
In many digesters, foaming can be a major
operational challenge. This is why Vaughan
has developed the Foambuster mixing
assembly, which can be added to any Rotamix
system or provided as a standalone system.
The Foambuster mixing assembly works by
using an integrally mounted splash-plate to
produce a field of droplets which suppress
foaming at the surface before it can interfere
with process operation.
ROTAMIX REDUCED ENERGY
ADVANTAGE
Vaughan Rotamix can be paired with a
Water & Wastewater Asia • March / April 2019