Carbon Monoxide Production during Bio-Waste Composting under Different Temperature and Aeration Regimes

Area of Science:

• Biochemical Engineering
• Environmental Microbiology
• Waste Management

Background:

• Biorefinery development often overlooks integrating biochemical production with conventional composting.
• Net carbon monoxide (CO) production is a known phenomenon during bio-waste composting.
• Oxygen (O2) concentration and temperature are key factors influencing CO formation.

Purpose of the Study:

• To investigate net CO production during bio-waste composting under controlled laboratory conditions.
• To analyze the impact of varying aeration rates and temperatures on CO generation.
• To explore potential improvements for CO production in composting processes.

Main Methods:

• Composting experiments were conducted under controlled laboratory conditions.
• Temperatures were varied across mesophilic and thermophilic ranges (35°C to 65°C).
• Aeration rates were systematically adjusted (2.7 to 7.8 L·h⁻¹).

Main Results:

• Highest CO concentrations were observed under oxygen-deficient conditions (2.7 L·h⁻¹).
• CO levels increased with temperature, reaching approximately 300 ppm at 65°C.
• CO production was noted in both mesophilic and thermophilic composting stages.

Conclusions:

• The study highlights the potential for biological CO formation by microorganisms possessing the CO dehydrogenase (CODH) enzyme.
• Findings suggest that composting can be optimized for enhanced CO production.
• Further research is recommended to characterize microbial communities and their CODH enzyme activity for efficient CO2 conversion.