Liquid state bioconversion continuous bioreactor of sewage sludge treatment: Determination and evaluation of mixed fungi growth kinetics

Abstract

Liquid state bioconversion (LSB), a bioremediation and biodewatering process was applied for sewage sludge treatment in this study. The LSB process is a non-hazardous, safer and environmentally friendlier method for ultimate sludge management and disposal compared to the other available technologies. The system presented in this study was developed by using mixed fungi of Aspergillus niger and Penicillium corylophilum to treat sewage sludge in a LSB bioreactor. This research was conducted in order to study the LSB process on continuous system in terms of kinetic coefficients determination. For the continuous LSB process, a mathematical model was developed from the basic principles of material balance based on Monod equation. By investigating the kinetics of substrate utilisation and biomass growth, the kinetic coefficients of growth yield coefficient (Y), specific microorganism decay rate (Kd), half saturation constant (Ks) and maximum specific growth rate (μmax) were found to be 0.79 g VSS g COD−1, 0.012 day−1, 1.78 g COD L−1 and 0.357 day−1, respectively.