# Diagram of Activated-Sludge Process

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## Schematic Diagram of Activated-Sludge Process

An important part of the municipal wastewater treatment is the BOD-removal. The removal of BOD is done by a biological process, such as the suspended growth treatment process. This biological process is an aerobic process and takes place in the aeration tank, in where the wastewater is aerated with oxygen. By creating good conditions, bacteria will grow fast. The grow of bacteria creates flocks and gases. These flocks will removed by a secondary clarifier.
On the following picture you see a schematic diagram of an Activated-Sludge System. This system is usually placed between the primary clarifier and the disinfection of a municipal wastewater treatment plant. A Flow Diagram of a Municipal Wastewater Treatment Plant with a suspended-growth process, gives you a better picture of the whole process of wastewater treatment.
The parameters of which the symbols are shown in the schematic diagram, are used to model a suspended growth process. In a Summary of all the Related Calculations you can calculate all the necessary design characteristics of a Complete-Mix Suspended Growth Process. By choosing in the navigator besides, you can calculate the design characteristics separately and find some extra information about the calculation and the theory about the characteristic design parameter.

Where:
 Q = flowrate of influent [m3/d] QW = waste sludge flowrate [m3/d] Qr = flowrate in return line from clarifier [m3/d] V = volume of aeration tank [m3] S0 = influent soluble substrate concentration (bsCOD) [BOD g/m3] or [bsCOD g/m3] S = effluent soluble substrate concentration (bsCOD) [BOD g/m3] or [bsCOD g/m3] X0 = concentration of biomass in influent [g VSS/m3] XR = concentration of biomass in return line from clarifier [g VSS/m3] Xr = concentration of biomass in sludge drain [g VSS/m3] Xe = concentration of biomass in effluent [g VSS/m3]