Fluid Separation Technology by Trucent

An Overview of the Centrifugal Dewatering Process

Trucent Brewery Wastewater Treatment Systems

There are many approaches to dewatering: belt presses, screw decanters, two- and three-phase centrifuges, even membrane-based ultrafiltration. Each has its strengths—as well as notable weaknesses.  

For many applications, centrifuge dewatering is the most suitable approach. A high-speed centrifuge gives you a great deal of control over the centrifugal dewatering process. This makes it possible to cope with variable flow and solid content while performing several separations in a single step (i.e., separating water from oil while also removing particulate—so-called “three-phase separation.”)  

The right centrifuge transforms dewatering from a simple cost-reduction strategy (as it is in wastewater treatment plants) to a source of new revenue. Efficient dewatering can increase the volume of an existing coproduct to the point where it can be reliably profitable. Or it uncovers a totally new revenue stream.

Dewatering Yields New Coproducts

Consider the food and beverage industry. Producing any food/beverage concentrate is, fundamentally, a dewatering exercise. Take for example cold-brewed coffee concentrates. Coffee producers benefit enormously from a good programmable three-phase dewatering centrifuge. With such a solution in place, they can take their brewed coffee—grounds and all—and feed it into the centrifuge. In a single pass that centrifuge will separate the water from the grounds and coffee concentrate. That water can then be fed back into the coffee production process, decreasing not just utility costs, but also the environmental footprint of the operation.

“You do something similar with algae production and processing,” explains Chris Clausen, engineering manager at Trucent. Algae is an important source of materials for dietary supplements, pharmaceuticals, and animal feed. “You take your algae production pond and feed it into a dewatering centrifuge. There you separate out the solid algae matter, an algae-rich heavy liquid phase, and clean water. The algae solids and slurry get mixed back together, and sent to the next step in the process. The water is sent back to your production ponds.”

But in order to do this, Clausen notes, you need a good three-phase dewatering centrifuge and a team to help you get that solution in place and running smoothly. “After each ‘shoot’ or solids discharge,” Clausen explains, “you’re disrupting the fluid dynamics in the bowl. Those need to be reestablished before the liquid phase starts separating again.” With a high-quality three-phase disc stack centrifuge, you can fine tune flowrate, back pressures, bowl rotational speed, and other variables to keep your separation running smoothly, despite variability in the feed.