Dynamic effect of total solid content, low substrate/inoculum ratio and particle size on solid-state anaerobic...

Area of Science:

• Biotechnology
• Environmental Engineering
• Renewable Energy

Background:

• Solid-state anaerobic digestion (SS-AD) is a promising technology for biogas production from organic waste.
• Process parameters like total solid content (TS), inoculation ratio (S/X), and particle size significantly influence SS-AD efficiency.
• Optimizing these parameters is crucial for enhancing methane yield and ensuring process stability.

Purpose of the Study:

• To evaluate the individual and interactive effects of TS content, S/X ratio, and particle size on methane production in SS-AD.
• To identify the key parameters governing methane yield during different phases of SS-AD.
• To understand the role of particle size and TS content interactions in water management within the SS-AD process.

Main Methods:

• A three-level Box-Behnken experimental design was employed for SS-AD batch tests.
• Wheat straw was used as the substrate, with TS content varied (15-25%), S/X ratio (28-47), and particle size (0.1-1.4 mm mean diameter).
• Dynamic analysis of methane production was conducted to assess parameter effects over time.

Main Results:

• The S/X ratio significantly affected methane production only during the start-up phase of SS-AD.
• Total solid content (TS) emerged as the primary parameter influencing methane production during the growing phase.
• A strong interaction between TS content and particle size was observed, highlighting the importance of water compartmentation.

Conclusions:

• Particle size optimization is crucial for efficient SS-AD, particularly in conjunction with TS content.
• Managing TS content is vital for maximizing methane yield during the main digestion phase.
• Water compartmentation, influenced by TS and particle size, plays a critical role in SS-AD process stability and performance.