Method for determination of methane potentials of solid organic waste

Area of Science:

• Biotechnology and Bioengineering
• Environmental Science
• Waste Management

Background:

• Assessing the energy potential of organic solid waste is critical for sustainable waste management.
• Standardized laboratory procedures are needed to accurately determine methane production from various waste streams.
• Understanding methane potential informs the efficiency of anaerobic digestion and biogas production.

Purpose of the Study:

• To describe and evaluate a laboratory procedure for measuring methane potentials of organic solid waste.
• To assess the practicality, reliability, and quality control of the developed methane potential assay.
• To determine methane potentials for source-separated organic household waste and individual waste materials.

Main Methods:

• Incubation of triplicate reactors (10g volatile solids) with thermophilic biogas plant inoculum at 55°C for 50 days.
• Regular methane production measurements using gas chromatography.
• Inclusion of blanks, cellulose controls, and evaluation of parameters like detection limit, repeatability, and reproducibility.

Main Results:

• Source-separated organic household waste exhibited a methane potential of 495 ml CH4/g VS.
• Fat and oil showed a lag phase, while protein samples were inhibited.
• Paper bags, starch, and glucose achieved 63%, 84%, and 94% of their theoretical methane potential, respectively.
• A detection limit of 72.5 ml CH4/g VS was established, suitable for the tested waste materials (200-500 ml CH4/g VS).

Conclusions:

• The described procedure provides a reliable method for determining methane potentials of organic solid waste.
• The method's evaluation confirmed its practicality and established quality control measures.
• Recommendations for addressing variability due to inoculum and waste heterogeneity are suggested to improve repeatability and reproducibility.