1. Introduction
Recirculating aquaculture systems (RAS) in intensive aquaculture
production are gaining more attention and interest, due to the potential
of reducedwater and energy consumption and to create a stable cultivation
tank environment. During the past ten years research on recirculation
systems and its application in aquaculture has been extensive,with
many studies considering technical aspects of system component design
and their performance. However, there is no single recommended
design for RAS.
One of the key problems in RAS is related to the load and accumulation
of suspended solids and in particular to the fine particles. Solids in
RAS vary greatly in size, fromlarge particles (cmsize) to fine and colloidal
particles (bμmsize), and are generated fromfeces, biofloc (dead and
living bacteria) and uneaten food. A challenge in conventional RAS is the
accumulation of the colloidal particle fraction