Wastewater Microbiology Articles

RAS Chlorination for Filamentous Bacteria Control (Essentials)

May 29, 2023

Ryan Hennessy

Wastewater Microbiologist

There are no general 1 size fits all solutions for troubleshooting biological wastewater treatment systemissues and while it is always preferred to address the root source of a problem, there are simply times inwhich this may not be feasible, or logistically practical. A common instance of these scenarios includestroubleshooting challenges with filamentous bacteria bulking. Filamentous […]

Read More

Low DO vs. Septicity: Separate Scenarios/ Growth Causes for (often) Undesirable Microbe Types.

May 4, 2023

Ryan Hennessy

Wastewater Microbiologist

There is an interesting and very important correlation with notable differences between the common terms “Low DO” (dissolved oxygen) and septicity. Due to this relatively complex relationship, there is often confusion regarding these terms. The goal of this blog is to briefly explain these differences and how each term should be thought of. What is […]

Read More

Why the MLSS Concentration is Not Always Representative

April 6, 2023

Ryan Hennessy

Wastewater Microbiologist

It is highly common and often successful to operate activated sludge treatment systems based on maintaining a targeted MLSS (mixed liquor suspended solids) concentration, however as with just about everything in wastewater, there are notable exceptions to the rule.  What makes up the MLSS? As can be seen from the chart above there are several […]

Read More

Should I Waste based on Higher Life Form Organisms?

April 6, 2023

Ryan Hennessy

Wastewater Microbiologist

Higher life form organisms such as stalked ciliates and rotifers may be easily viewed under brightfield microscopes. They are fascinating, motile, and easy to recognize however process control changes should not be based strictly upon higher life form organisms and their abundance. The best analogy to use is that “you are what you eat” and […]

Read More

Sludge Bulking: Microthrix

March 28, 2023

Ryan Hennessy

Wastewater Microbiologist

One of the most challenging problems commonly encountered in biological wastewater treatment processes is sludge bulking due to overabundance of Microthrix filament types. What is Microthrix? Microthrix filament types are recognized due to their Gram-positive staining characteristics and are generally 0.8 µm diameter with no visible septa (cell walls). Microthrix are recognized to grow on […]

Read More