a bugs life

This area of the website is dedicated to the microbiology of the wastewater treatment system and the surrounding environment. It is our goal to provide an educational resource for learning about the sludge bugs and other interesting environmental bacteria that may be impacted by a wastewater treatment

Free Swimming Ciliate: Free swimming ciliates are resident bugs in the activated sludge system. They are single celled protozoa and often round or oval shaped. These microorganisms get their name by the presence of short hairs or cilia that they can use for motility. They proliferate under medium food to microorganism ratio and medium mean cell residence time conditions. These protozoa are indicative of a stable activated sludge


Amoeba: Amoebae are resident bugs in the activated sludge system. They are single celled protozoa. Amoebae can have a flexible membrane and are found in all shapes and sizes. They move by extending a leading foot, called a pseudopod. Once the pseudopod is extended, the amoeba has to move its entire cytoplasm to follow. This slow movement makes them inefficient feeders. These microorganisms proliferate under high food to microorganism ratio and low mean cell residence time conditions in the activated sludge.