Modeling and simulation of anaerobic startfied biofilm for mathane production and prediction of multiple steady states

Abstract

The present work deal with the modeling and anaerobic metabolism in a startified biofilm consisting of two distinct layers of microorganisms in a fixed film reactor.The model is applied to steady state conditions and its based on substrate utilization kinetic and mass transport.The model assumes that the substrate is first metabolized by the outer acidogenic layer and the subsequent product are metabolized by the inner layer of methanogens to produce finally mathene and carban dioxcide.The model considers slab geometry of the boiofilm,monod kinetics for growth rate of acidogence and the inhibition effect of volatile fatty acid on growth rate of mathenogence.The defusion equations are solved simultaneously using a modified form of the technique of orthogonal collocation of finite elements to obtain concentration of profile and the rate of mathene production per unit volume of the biofilm is determined cimputer simulation are carried out of study the effect of various parameters on the of mathene production and to investigate the existences of multiple steady states.The simulations showes that fir a range of parameters value three steady states exit.It is showen the upper steady states with highest rate of mathene production may lead to unsatisfactory reactor performance.