Mathematical modelling of prefermenters—I. Model development and verification

A dynamic mathematical model of prefermentation is presented. Prefermentation is becoming an increasingly popular unit operation in biological nutrient removal wastewater treatment plants. The aim of the prefermenter model is to provide a tool for optimisation of prefermenter design and operation. Model assumptions, equations and parameters are detailed. The major specification for the prefermenter model is that it is relatively simple, but can still describe the effects of the main design and operating parameters on volatile fatty acid (VFA) production in prefermenters. The model is verified by comparing its prediction with experimental data presented in the literature. Predicted and measured steady-state effluent VFA, soluble COD and ammonia-N concentrations are compared for varying hydraulic and solids residence times. The correspondence between experimental data and model prediction is good.