There are plenty of microorganisms that use the organic matter present in wastewater and reduce the biological oxygen demand (BOD). These microorganisms are included beneficial bacterias, protozoa, metazoa, algae, and fungi, which breaking sewage down.
Hyunjun Song many micro organisms are involv3d when we are talking about the waste water treatment plants particularly the link shared here with might give you some idea about the same
dear Hyunjun song, the aeration tank will contain aerobic microbes (the ones that need oxygen for their survival). How many different types of microorganisms will be present will depend on many factors, including the geographical location, type of waste, type of pre-processing, etc.
Dear Hyunjun Song,There are many kind of microrganisms can be seen in waste water treatment plant basicaly Algae,bacteria ,protozoa ,fungi also.further informatio you can search google ..