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Actual vs. Wahlberg-Predicted RAS TSS

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May 25, 2020


Hydrogen peroxide can be used to increase the dissolved oxygen (DO) concentration in an aerobic bioreactor, often referred to as “DO supplementation.” Using peroxide is rarely a first choice because chemically increasing DO is more expensive than using a mechanical method (diffused aeration, mechanical mixing, etc.). But i...

September 10, 2019


In this post I'm going to discuss how you can estimate the solids concentration in the return activated sludge (RAS) using the treatment plant influent flow rate, the RAS flow rate, and the mixed liquor suspended solids (MLSS) concentration. This approach is new for me, having read about it in a great, new textbook from Er...

January 2, 2019

Detailed Review of Bioaugmentation

Bioaugmentation is the addition of a specially prepared bacterial culture to a bioreactor (aeration tank, oxidation ditch, etc.). The goal of bioaugmentation includes objectives such as: 1) increasing the density of more desirable bacteria, 2) achieving a specific operational goal such as degrading co...

May 2, 2017

The nitrogen cycle and other graphics are shown here. These graphics are intended to inform those who operate (or need to know about) nitrifying wastewater treatment systems. The first graphic below is one of the most common and you will come across this in several different textbooks.

September 26, 2016

Wastewater Temperature in the Bioreactor

Operators know that when the temperature of the wastewater entering the bioreactor is too high, it can have an adverse impact on the microorganisms in the activated sludge system. How high a temperature is too high? There are many opinions on this subject so I thought I would combine my own expe...

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