ADM1 based mathematical model of trace element complexation in anaerobic digestion processes

Area of Science:

• Environmental science
• Biotechnology
• Chemical engineering

Background:

• Trace elements (TEs) play a crucial role in anaerobic digestion (AD) processes.
• Understanding TE complexation and precipitation is vital for optimizing methane production.
• Existing models often lack the complexity to fully capture these interactions.

Purpose of the Study:

• To develop an extended anaerobic digestion model (ADM1) that incorporates trace element complexation and precipitation.
• To investigate the influence of trace element interactions with VFAs and EDTA on methane yield.
• To assess the impact of initial calcium and magnesium concentrations on anaerobic digestion performance.

Main Methods:

• An extended ADM1 model was developed, incorporating complexation reactions of trace elements with VFAs and EDTA.
• The model includes precipitation/dissolution reactions and biodegradation processes for trace elements.
• The kinetic model tracks 90 state variables, with modifications to the charge balance to account for new components.

Main Results:

• The enhanced model successfully simulates the effects of TE-EDTA/VFA complexation on methane production.
• The model predicts the influence of initial calcium and magnesium concentrations on the overall process performance.
• The dynamics of 90 state variables were tracked, providing a comprehensive view of the AD system.

Conclusions:

• The proposed extended ADM1 model provides a robust framework for simulating trace element behavior in anaerobic digestion.
• This model can be a valuable tool for predicting and optimizing methane production under varying conditions.
• The findings highlight the importance of considering complexation reactions for accurate AD process modeling.