Design and performance of hydrocyclone for suspended solids removal from biofloc aquaculture system

Abstract

Solid-liquid separation is a crucial process for controlling suspended solids in recirculating aquaculture systems (RASs). The hydrocyclone is an alternative device that uses centrifugal force to separate solids from liquids. The hydrocyclone offers rapid operation, easy installation, and high energy efficiency. This study focused on optimizing the design and evaluating the efficiency of hydrocyclone, specifically for RASs incorporating biofloc technology (BFT). The critical parameters, including cut-size diameter, particle density, viscosity, and flow inlet, were collected for hydrocyclone design using Bradley's geometric model. The resulting hydrocyclone dimensions were as follows: diameter (Dc) of 3.04 cm, feed inlet diameter (Di) of 0.40 cm, vortex finder diameter (Do) of 0.61 cm, apex diameter (Du) of 0.21 cm, hydrocyclone length (L) of 20.80 cm, vortex finder length (l) of 1.00 cm, and cone angle (θ) of 9°. The hydrocyclone efficiency was tested at varying inlet pressures of 0.2, 0.4, 0.6, and 0.8 bar. Among these levels, an inlet pressure of 0.4 bar yielded the highest performance, with total coarse efficiency (Eu) of 62.99%, total fine efficiency (Eo) of 37.01%, and reduced efficiency (E') of 45.69%. With these efficiencies, the designed hydrocyclone is well-suited for use in BFT, where biofloc is cultivated and excess solids must be removed. By effectively separating solids, the hydrocyclone assists in maintaining the balance of biofloc, supporting both water quality and nitrogen treatment in the RASs. © Published under licence by IOP Publishing Ltd.