Know your Biota (bugs)!

The primary reduction of organic material within a wastewater treatment plant is performed by a number of different types of microorganisms. Most of the organisms can be categorized as either bacteria, protozoans or metazoans. These organisms are present in the air, the soil and most, if not all, warm-blooded animals, including man.


Identifying and understanding the various types of organisms, thier functions and properties provides insight into the treatment process and process control decisions. The bacteria, single-celled and multi-celled animals that consitute the majority of these organisms, are generally identified by the term "sludge." The absence or presence of free oxygen will determine if the sludge is anaerobic or aerobic.


The lowest life form identified within treatment-plant sludge is bacteria. One of the properties of bacteria is that they usually live in a colonial structure called "floc." The structural nature and characteristics of a significant portion of the floc particles directly affect physical properties that contribute to treatment- plant efficiency. The floc particles may be identified for shape, size, strength, surface area, density and the presence of higher life forms.