Model-based scale-up and performance of the Biogas Tower Reactor for anaerobic waste-water treatment

The Biogas Tower Reactor (BTR), a new type of reactor for anaerobic waste-water treatment, is presented. The characteristic features of the BTR are the tower shape, its modular structure and the internal installations. Gas loading, mixing and sludge distribution can be controlled. A settler is installed on top of the reactor. Performance data of a pilot-scale BTR are presented for the treatment of a yeast production effluent. Although these effluents are known to be difficult to treat anaerobically (inhibiting products (H2S), pellets with poor settling properties), excellent results are obtained with this reactor type. The main emphasis in scale-up was placed on the height of the reactor and its effects on the hydraulic loading and the sludge distribution. The crucial points in scale-up are the connecting mechanisms between adjoining modules with regard to sludge distribution and liquid mixing. The mechanisms have been mathematically quantified and checked on both laboratory-scale and pilot-scale. Finally, the mathematical model has been extrapolated to predict the performance of a full-scale BTR.