Understanding the biological players in wastewater treatment is essential for sustainable team/facility management and individual professional growth.  Ultimately, for a facility this knowledge translates into permit compliance, cost efficiency, and proper emergency response. There are four groups of organisms involved in biochemical oxygen demand (BOD) removal which are illustrated in the figure above and summarized as follows:

1. Floc Formers - Bacteria and Protozoa that enable flocculation and settling of the beneficial biomass in the clarifier. We need these for the clarifier to work.
2. Ordinary Heterotrophic Bacteria (OHOs) - Bacteria and Protozoa that are responsible for removal of organic matter (BOD). The work-horses.
3. Predators – Protozoa organisms that prey on beneficial bacteria. The circle of life happens at the microbial level too.
4. Nuisance Organisms - Filamentous bacteria / organisms that interfere with the treatment process. Not all bad, but not all good either.

All of these organisms are simultaneously active and interacting with one another the reactor.  A solid understanding of treatment Basics like this keeps operations teams grounded.  For those new to the industry, this information is the foundation of future knowledge and skills in a very rewarding career.  For more senior professionals, it can be a welcomed refresher in an industry that is constantly changing/ evolving.  I have numerous courses that cover the basics of wastewater treatment, and am pleased to offer 20% off for a limited time. Download it here.