Validation of ADM1 by using TPAD operation

Abstract

The aim of the study presented was to implement a process model to simulate the dynamic behavior of lad-scale process for TPAD (temperature phased anaerobic digestion) process of composite substrate mixed dog food with flour. The model concept implemented in the simulation software MATLAB 6.1 is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modeling of anaerobic process. In the present study the original model concept has been adapted and applied to replicate TPAD process. In this experimental work, HRT is controlled 4.2 d and 11.5 d of each reactor. By contrast, SRT is decreased stepwise from 230d to 23d. The organic loading rate is 15.4 g COD/d, 25.2 g COD/d and 35.7 g COD/d. The COD removal efficiency is consistently about 46.3%, 50.0% and 51.3% at the thermophilic reactor, and that is about 95.3%, 95.9% and 96.2% throughout the whole process completely. The methane conversion rate is 56.3%, 60.9%, and 64.4% in each organic loading rate. In additions, the values of yield in the whole system are 0.59, 0.61 and $0.64 g CH_4 /g COD_{removed}$ with each organic loading rate. In the model work, ultimately, 17 parameters were identified based on the sensitivity analysis. Among them, methane, VFAs, ammonia, and soluble COD are estimated to these parameters. Soluble COD has the most sensitive to these parameters. Of all parameters sensitive to TPAD process, there are maximum specific uptake rate $(k_{m.pro}, k_{m.ac}, k_{m.c4})$, disintegration constant $(k_{dis 35/55})$, and decay rate $(k_{dec})$. In the model output of methane production, at the beginning step, model output is not accord with experimental data, because model is not sensitive to varying points. That is, it means that ADM1 have to modify of the problems of these parts. In the batch test, ADM1 can be estimated throughout using the simulation with variable of Total ammonia nitrogen (TAN) concentration and pH. Model si...