Assessment of kinetic and macroenergetic parameters for a mesophilic anaerobic fluidised-bed reactor treating wastewater derived from the production of protein isolates from extracted sunflower flour

A study of the kinetics of the anaerobic digestion process of wastewater de rived from the production of protein isolates from extracted sunflower flou r was carried out in a laboratory-scale fluidised bed reactor with saponite as support for the mediating bacteria at mesophilic temperature (35 degree sC). The reactor operated satisfactorily between hydraulic retention times (HRT) of 1.1 to 20.0 days, removing between 98.3 and 80.0% of the initial c hemical oxygen demand (COD). Macroenergetic parameters, calculated using Gu iot's kinetic model, gave a yield coefficient for the biomass (Y) of 0.075 g VSS/g COD and a specific rate of substrate uptake for cell maintenance (m ) of 0.021 g COD/g VSS day. The experimental results also showed the rate o f substrate uptake, R-s (g COD/g VSS day) correlated with the concentration of biodegradable substrate, S (g COD/1), through an equation of the Michae lis-Menten type. This proposed model predicted the behaviour of the reactor very accurately showing deviations lower than 10% between the experimental and theoretical values of substrate uptake rates. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.