A simple unstructured kinetic model for anaerobic treatment of a class of agro‐industrial waste

Abstract

BACKGROUND Dynamic modeling of the anaerobic treatment of agro‐industrial waste can help determine optimal operating conditions to maximize the process performance. For this, it is necessary to select an appropriate model and adapt it to the specific conditions of the substrate. In this work, a simple unstructured kinetic model for the anaerobic treatment of different agro‐industrial waste is proposed. The proposed model considers the three most relevant stages of anaerobic digestion (AD) and can be adapted for the treatment of different substrates, modes of operation (batch or continuous), and/or generated products (VFA or methane production), thus requiring a minimum of process macroscopic measurements. RESULTS To evaluate the scope of the model, two case studies were analyzed: (i) methane production from tequila vinasse and agave hydrolysates, and (ii) volatile fatty acids (VFA) and biogas production from raw cheese whey. For each case, parameter estimations were performed using the Levenberg – Marquardt algorithm, which yielded a simplified model with high determination coefficients (R2 > 0.95). Moreover, the kinetic parameters estimated were consistent physically and statistically. CONCLUSION Numerical results show that the proposed model can satisfactorily describe the dynamic behavior of the key variables of the three types of agro‐industrial waste evaluated. Therefore, the proposed model might be advantageous to determine the conditions that maximize performance without risking process stability. © 2022 Society of Chemical Industry (SCI).