Biological treatment of wastewater through biological filters has been in practice for a long time.
It offers many advantages.
Here in this article I mention the two basic groups of biological filters and present a few details about the design of relatively new form of one of these filters.
The biological treatment of wastewater in biological filters is achieved by alternately exposing the filters to wastewater and air.
This allows the microorganisms to grow and they form a layer on the biological filter surface.
The microorganisms that exist in this layer breakdown the constituents in the wastewater.
The organic particles present in the wastewater are adsorbed by these microorganisms and are degraded through an aerobic reaction.
These biological filters can be grouped together under two categories.
These two groups are - rotating biological reactor and the fixed media filters.
The formation of a film of microorganisms is common to both these groups.
One type of fixed media filter that is rather new is the Biotower.
This has plastic waffles arranged in the shape of a honeycomb structure.
This is where the film of microorganisms is formed and serves the purpose of biological treatment of wastewater.
This contains a growth medium that helps in the growth of a culture of commercially available bacteria.
A nutrient solution is also provided for bacterial growth containing a mixture of ammonia and phosphorous.
The bacterial culture, the influent wastewater and the nutrient solution are all introduced and mixed at the bottom of the Biotower.
This mixture in then forced upwards with the help of a powerful draft of air.
The treated wastewater emerges out of the top portion of the Biotower.