Modelling of design and process control of secondary clarifier by solid flux analysis with control of bulking using chlorine for treating dairy wastewater

Abstract

Filamentous bulking is one of the common and serious problems that the secondary clarifier encounters in the Activated Sludge Process (ASP). An attempt has been made to model the design of the secondary clarifier addressing the problem of filamentous bulking using chlorine addition and the process control during the fluctuations in the influent characteristics in treating the dairy wastewater. There are innumerable bacteria, present in any wastewater activated sludge and they are of different types. An initial investigation was made in this research work to isolate and identify the predominant bacteria present in the dairy wastewater. Bacillus was found to be present in most of the samples collected, followed by Pseudomonas. The sludge was found to contain two types of filamentous organisms viz Sphaerotilus natans and Nostocoida limicola. The solid flux theory was adopted for the design and operation of the clarifier. The results of neural network model were compared with the results of regression model and experimental results and found to be much closer with experimental results. Mathematical models were developed by generating data relating Cu with the ratios of operational and design values of R, Q and S by solids flux approach using MATLAB programs For any fluctuation in the hydraulic loading within the specified range, the modifications required to be made in either of the parameter Co, Cu or R can be predicted from the diagrams. Thus these diagrams are very handy to evaluate the operational control options and to design secondary clarifier.