Tailoring biochar properties for anaerobic digestion: Enhancing performance under high organic loading

Area of Science:

• Biotechnology
• Environmental Science
• Materials Science

Background:

• Anaerobic digestion (AD) is crucial for food waste management and biogas production.
• Optimizing AD efficiency is vital for sustainable energy generation.
• Biochar, a carbon-rich material, shows potential for improving AD processes.

Purpose of the Study:

• To investigate how biochar's physicochemical properties, dosage, and particle size impact food waste anaerobic digestion.
• To determine the optimal conditions for biochar application in AD.
• To evaluate the effect of biochar on digestion time and methane yield.

Main Methods:

• Food waste anaerobic digestion was conducted at a feedstock-to-inoculum ratio of 2.4.
• Biochar was produced from spruce softwood via microwave-assisted pyrolysis at varying power levels (750, 1250, 1750 W).
• Biochars were tested at dosages of 10, 20, and 30 g/L, with variations in particle size.

Main Results:

• Biochar performance in AD was significantly influenced by its properties and dosage.
• The biochar produced at 1750 W and applied at 30 g/L maximally reduced the lag phase by 59.4% and accelerated methane yield.
• Finer biochar particle size improved early digestion, but dosage and pyrolysis conditions had a greater impact.

Conclusions:

• Biochar characteristics, dosage, and particle size synergistically enhance anaerobic digestion of food waste.
• Optimized biochar application can significantly reduce digestion time and improve methane production efficiency.
• This study provides insights for utilizing biochar as an effective AD additive under high organic loading conditions.