It is today acknowledged that Moving Bed Bioreactor technology (MBBR) is the most optimal in biological filtration, not just for aquaculture, but for most types of wastewater.
At IAA, we have been working with MBBR technology since 1998, having used stationary filter types prior to that.
The thinking behind MBBR technology was originally to move the media in the water instead of having to move water up and over/through the bio media. With MBBR, one then has a minimum head loss and it makes it easier to pump water around and one can use more efficient low head propeller pumps. Pumps that not just are more energy efficient than other types of pumps, but also last longer.
The movement of the bio media takes place with an aeration in the bioreactor vessel. The normal aeration configuration for MBBR is by diffusion in a diffusor grid in the bottom and this is often termed Standard MBBR and used by most, being it in aquaculture or other sectors. IAA have however, taken the MBBR concept a step further in the form of the Clearwater MBBR© technology.
In standard MBBR, the aeration is an upward force lifting the bio media. However, as an air bobble starts small from the bottom there is not vigorously enough movement until further up where bubble size increases and gather the necessary momentum.
The aeration configuration in the Clearwater MBBR does not consist of an aeration grid on the bottom covering the entire area, it consists of a peripheral aeration ring with upward force and a number of riser pipes (airlifts) located at certain distance from each other and from the peripheral aeration. All devices have upwards movements of air and bio media, but also a force that draws them back down to the bottom (and up again) by the suction force of the airlifts (just like a pump). This is a very dynamic motion where bio media elements are concentrated in the airlifts and on their way up through them and in principle what facilitates the bio film control. Not just do we achieve full movement and mixing with this configuration, less energy is needed compared to Standard MBBR.