Activated Sludge
Control and Simulation


Check out these three downloadable programs:


Activated Sludge Simulator Program

The ESIM Activated Sludge Simulator Program is a powerful, flexible, enjoyable way to learn how the activated sludge process works. ESIM lets you design and operate a plant, getting results in seconds instead of days. You can try different strategies on the same operating conditions. You can display the results in a variety of ways, and even create DOS files containing results that you can analyze separately.

Shift-click to download:

"User's Manual" - "List of Commands" - "Download Demo ESIM"

The Dynamic Sludge Age (DSA) program computes the "true" mean cell residence time for an activated sludge plant which is not at steady-state. Shift-Click to download documentation and programs to perform this calculation:

DSA.EXE - This is an executable program to compute the DSA.

DSA.WK1 - This is a spreadsheet to compute DSA. It runs under either LOTUS or EXCEL.

DSA.TXT - This has documentation and references for the DSA calculation.

The SOLDIST program predicts the mixed liquor and return sludge suspended solids concentrations in a step-feed activated sludge process, and computes hydraulic detention times, contact times, and either steady-state MCRT at a given waste flow rate, or the waste flow rate required for a given MCRT.

This program allows decoupling of waste flow rate and return flow rate. That is, it enables the operator to determine how to change the waste flow rate in order to keep the same MCRT, if the return flow or step-feed distribution are changed.

To download this program, Shift-Click on 'SOLDIST'.

The EXCEL spreadsheet program THICKEN.XLS (shift-click to download) computes and plots the steady-state concentration distribution in a thickener, and the corresponding flux curve. This is mainly an educational tool to learn the influence of several variables on sludge blanket height and concentration distribution. The variables include influent flow and concentration, underflow velocity, and sludge volume index.

The program uses a compressive thickening model. This model has several advantages over conventional flux theory, including the ability to predict concentration distributions and blanket heights in underloaded thickeners. Documentation and references a re in the spreadsheet.

For more information, contact:

David A. Vaccari