Modeling the solids system of an Activated Sludge process starts with determining the Solids Yield Coefficient and the Endogenous Decay Coefficient.  This is accomplished by performing a statistical correlation between SRT and F/M ratio.

Using site operating data over a specified time period, we will compute the coefficients needed to determine the relationship between sludge production and organic load vs. mixed liquor concentration/SRT.  In the example above the solids yield coefficient is .635 pounds of solids produced per pound of organic (BOD) removed in the aeration system.  The decay or endogenous respiration coefficient, .00276 pounds of solids per pound of MLSS under aeration per day, defines the daily conversion ratio of solids to carbon dioxide and water.  The correlation coefficient of .7264 defines a good "fit" by regression analysis. 

BUTTONS:

	Selects highlighted Basin.
	Selects all basins.
	Un-selects highlighted basin.
	Un-selects all basins.
	Calculates the Solids Yield Coefficient, the Endogenous Decay Coefficient (mass of cells lost during endogenous respiration) , and Correlation Coefficient.  A dialog box will display the coefficients.  Click OK and the plot will be shown.
	Returns to the main menu.

NOTE:  Coefficients of biological processes are site specific and change from time to time and, at least, seasonally.

Field Descriptions

Solids Yield Coefficient: Pounds of solids produced per pound of organic (BOD) removed in the aeration system.

Endogenous Decay Coefficient: Mass of cells (solids) lost during endogenous respiration.

 

EXAMPLES: