HOW TO IMPROVE WATER MANAGMENT IN FISH REARING
Essential Functions of Effective RAS Water Management are:
These elements provide a clean environment conducive to the health and growth of the fish. Typically these functions are performed by one or more discrete components per function. This leads to systems that are complex, unreliable and costly to install and operate.
The multi-functional VAL™ consolidates many of these components and functions providing a streamlined system that simplifies RAS water management yielding a process that is more effective, efficient, reliable, sustainable, and profitable than traditional approaches.
Effectiveness in Treating Fish Rearing Water
Below are the results of a VAL™ installation after the drum filter in Barramundi RAS. The system had a biomass of 12,000 lbs and a recirculation rate of 350gpm. Total Suspended Solids (TSS), UltraViolet Transmittance (UVT) and Input Power were measured at the start of the demonstration and after stabilization.
The test results indicate that the VAL™ reduced the TSS by 45%. As a result of the reduction in TSS the VAL™ increased the UVT by 22%. UV performance will be three times as effective in the VAL™ treated water due to reduced particle shielding.
Before VAL™ Treatment
After VAL™ Treatment
Using a VAL™
Foam Fractionation Capacity
The microbubble airlift of the VAL™ provides foam fractionation capture of the fine particulates from the rearing water. This particulate laden foam is then removed by vacuum extraction. The VAL™ removes up to 99% of suspended particles less than 40 μm in size. As a result it provides a drastic increase in water clarity and UV transmittance while reducing the BOD load and clogging of the bio-filter. The VAL™ performs this particulate removal at low energy input. Depending on the application, energy input for particulate removal can range from 30 to 115 Wh per m water treated.
Biosecurity Effects: Virus & Bacteria Reduction
The VAL™ can provide a 3 log reduction in virus concentration by foam fractionation and vacuum
extraction. The VAL™ reduces the need for or
enhances the effectiveness of ozone or UV treatment.
Virus Density Reduction After VAL™ treatment
CO2 Stripping Capacity
The VAL™ has a Standard CO2 Transfer Rate (SCTR) of around 11.2x10-5 KgCo, m s providing a stripping efficiency around 15-20 g CO2/m /h of air injected. The combined effect of the vacuum and airlift microbubble injection results in low stripping energy, around 5-10 Wh per m of water treated.
N2 Stripping Capacity
The VAL™ is also effective at stripping other problematic dissolved gases such as N2, thereby preventing hyper saturation and its consequence, gas bubbling disease.
The VAL™ is an effective device for O2 dissolution. Pure oxygen can be injected "counterflow" of the water cascading down the outer tube. As a result O2 dissolution efficiency of up to 98% is obtainable. This results in an O2 dissolution as high 160% of saturation at the VAL™ outlet.
O2 Dissolution Capacity
The airlift makes the VAL™ an effective water circulation device. Standard airlift water transport is around 3 times the water volume per volume of air injected. With low air injection it is possible to lift 3 to 10 times the volume of water per volume of air. Water circulation is accomplished with low pumping energy, around 3 Wh per m of water circulated.