The most important component of a RAS system is the mechanical filter, the characteristics of which depend on the performance of the entire system.
This must work at resolutions ranging from 20 to 80 microns related to the flow rate, biological loading of the system, and the fish feed algorithm.
To consider an efficient filtration system, the entire volume of water available in growing tanks should be subjected to the timely filtration process (2 times per hour).
The vast majority of these “drum” filters are automated and require only minimal intervention to periodically disinfect this system.
Since the sieves having a resolution of the order of tens of microns are washed under very high pressure (more than 4 bar.), the performance of the water “constant flow” through these very fine holes ensures a constant flow of the entire recirculation system.
The standard internal flushing system of a mechanical filter basically works by closing very fine holes with solids and semi-solids in suspension, which makes the water to not pass as easily and thus increase the water level inside the sieve cylinder.
In this situation this level is sensed by a sensor that gives the command to rotate and simultaneously wash the sieves.
Clogging of the holes leads to a progressively negative flow of water, which makes the performance parameters drop by as much as 60%.
A major improvement achieved by Olooson and its partners is to ensure an almost linear flow with decreases of only 3% and not in leaps (as a form of a sawing tooth).
This mode of operation is positively felt at the biofilter level because a constant flow rate is one of the optimum operating conditions of the entire nitrification process at the biological filter.