The Finlayson family engaged FBD to build a recirculating aquaculture system to grow on eels captured in the wild. The RAS includes 20 x 9,000 L Polymaster tanks with a filtration system designed around a peak feeding rate of 525 kg/day. Water is pumped into the tanks through 4 x 960 W Pentair UV sterilisers, then through an oxygen cone (FBD Model 1) on each tank to maintain stocking densities up to 150 kg/m3. Water leaving the tanks is gravity-fed via floor channelling to a Faivre 16/120 drum filter fitted with 36 micron screens, then through a moving bed bioreactor (MBBR) and bio block degassing unit into the sump. Additional filtration is provided by an RK600PE freshwater fractionator, to which ozone (RK2, 15 g/hr) is added to enhance water quality control.
Further control over dissolved solids is ensured by an AST (Aquaculture System Technologies) propeller-wash bead filter with an automatic backwash control system. Australian designed and manufactured turbine pumps were chosen for energy efficiency, serviceability and reliability, and their submersed design negates any concerns over nitrogen super-saturation. Feed is delivered automatically via an Arvo-Tec feeding system over 24 hours at 1-3% of biomass per day.
