A model was developed to describe the performance of sequencing batch
reactors. The model was structured upon four processes (substrate grow
th depending, product growth depending, hydrolysis, and decay processe
s). The model parameters, two parameters, were evaluated using one set
of experimental data obtained from the literature. The model was then
used without adjusting any parameters to predict five other experimen
tal data sets. The excellent predictive nature of model was validated
for a wide range of fill to react period ratio (1/3:3/1) and also for
a wide range of COD loading (340:3300 mg/l).