Kinetics of an anaerobic fluidized bed system used for the purification of fruit processing waste water

A study of the kinetics of the anaerobic digestion of fruit processing waste-water was carried out. A 1.25 1, fluidized bed bioreactor operating at 35 °C and containing a saponite-immobilized biomass at a concentration of 8.95 g volatile suspended solids (VSS) per litre was used. The bioreactor worked satisfactorily in a range of hydraulic retention times from 2.5 to 12.5 days and eliminated more than 97% of the initial chemical oxygen demand (COD) in all instances. Guiot's kinetic model was used to determine the macroenergetic parameters of the system, and showed it to have a yield coefficient for the biomass Y of 0.090 g VSS per g COD and a specific rate of substrate uptake for cell maintenance m of 0.035 (g COD per g VSS) day?1. The experimental results also showed the rate of substrate uptake (Rs, g (COD per g VSS) day?1) correlated with the concentration of biodegradable substrate (Sb, g COD 1?1) through an equation of the Michaelis-Menten type.