Activated Sludge Calculations with Excel

The activated sludge process is very widely used for biological wastewater treatment. This course includes background on biological wastewater treatment, a general description of the activated sludge process, information about several variations of the activated sludge process, discussion of design calculations for an activated sludge aeration tank, and discussion of activated sludge operational calculations. Example calculations and sample Excel spreadsheets for making the calculations are also included.

After completing this course you will be familiar with the common variations of the activated sludge process used for biological wastewater treatment and be able to make typical aeration tank design and operational calculations.

Topics: The equation for biological oxidation and how it fits into the organic carbon cycle The equation for photosynthesis and how it fits into the organic carbon cycle The major components of an activated sludge wastewater treatment system The differences between an extended aeration and conventional activated sludge system The differences between a contact stabilization and conventional activated sludge system Calculation of required aeration tank volume (in U.S. units) for a specified volumetric loading, hydraulic residence time, or aeration tank F:M ratio, if given suitable aeration tank influent and aeration tank parameter information. Calculation of required aeration tank volume (in S.I. units) for a specified volumetric loading, hydraulic residence time, or aeration tank F:M ratio, if given suitable aeration tank influent and aeration tank parameter information Calculation of the required activated sludge recycle flow rate, waste activated sludge flow rate, and aeration tank F:M ratio, if given suitable wastewater stream and aeration tank information along with the desired value for sludge retention time.

Intended Audience: water treatment, hydraulic, civil, environmental, chemical engineers, and other engineers whose job description may require a basic knowledge of utilizing Excel spreadsheets to perform activated sludge calculations.

Publication Source: Harlan H. Bengtson, PhD, PE