MODELING THE GROWTH OF AN OLIGOCHAETE ON ACTIVATED-SLUDGE

A dynamic energy-budget model (DEB model) was extended to describe the growth of Nais elinguis, a common oligochaete species frequently occurring in sewage treatment plants. Nais elinguis reproduces asexually by dividing into an anterior and a posterior naidid. The daughter naidids initially have different growth rates due to differences in energy reserves. The fit of the model showed a good description of the length measurements. The parameters of the model, such as maintenance rate coefficient and energy conductance, which represent physiological features of the organisms, facilitate insight into the processes underlying naidid growth. A numerical method was developed to predict asexual reproduction. The presented model is a first step towards a more comprehensive knowledge and modelling of organisms in an activated sludge plant and is therefore interesting from a wastewater management point of view.