Scale-up by mathematical modeling of anaerobic reactors for yeast wastewater treatment

Abstract

Wastewater treatment by anaerobic digestion is a viable solution for the discharge of industrial liquid wastes with different levels of contamination. The kinetics of the anaerobic digestion reaction, in laboratory tubular reactors, by a consortium of microorganisms to treat liquid waste from a feed yeast industry does not adjust to a Monod equation, but to a numerical adjustment carried out with the Table Curve 2D program. Where 0.65 d-1 was determined as the maximum cell growth rate and other parameters of the microbial kinetics. The error with which the selected model describes the experimental results is ± 24 mg/L. The mathematical analysis of the models used was carried out in MATLAB® software, which allowed the determination of a novel dimensionless number, named Gai, which facilitated the analysis, scaling by mathematical modeling and dimensioning of the anaerobic reactors at industrial scale for the treatment of 430 m3/d of waste. Tubular bioreactors with a total height of 18,93 m and 2,4 m in diameter were dimensioned. The required flow rate of 2,91 m/h was also determined. The Gai number is a relationship between the governing phenomena of the studied process, the conversion and residence time constants, with two main mechanisms involved in the process: convective flow and conversion. Once it has been demonstrated that there are no diffusional restrictions in the anaerobic leaf.