Investigating the effect of changing the decay coefficient in an activated sludge model

Abstract

The activated sludge process (ASP) is widely used to treat both domestic and industrial wastewaters. The main disadvantage of the ASP is the expense of disposing of excess sludge, which can account for between fifty to sixty percent of the operating costs of a treatment plant. We examine a model for the ASP in which the biochemical processes are represented by a simplified version of the well known activated sludge model No. 1. A promising method to decrease sludge production is to increase sludge biodegradability. A variety of experimental methods exist to do this, such as enzyme treatment, ozonation, heat treatment, and ultrasound. We investigate the effect of increasing the decay coefficient upon two important process variables: the chemical oxygen demand and the total suspended solids.

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