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July 16, 2020

This post contains two sections with Section 1 covering Wastewater Solids production and Section 2 describing Influent Wastewater Characteristics.

Section 1: Wastewater Solids

It can be helpful to quickly estimate solids production in wastewater. Certainly, each wastewater treatment plant and its collection system, with variable ratios...

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 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...

September 5, 2016

Activated Sludge Design Parameters

This is a handy chart from the well-known Metcalf & Eddy handbook (Metcalf & Eddy. Wastewater Engineering: Treatment and Reuse. 4th ed. Boston: McGraw-Hill, 2003).

Clicking on the image will open up a PDF version of the chart for printing or to give you a larger view.

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