Development of mixed inoculum for methane enriched biogas production

Area of Science:

• * Environmental Microbiology
• * Renewable Energy Sources
• * Waste Management

Background:

• * Biogas production relies on microbial consortia present in inocula.
• * Diverse waste streams offer potential for optimizing biogas yields.
• * Characterizing different inoculum sources is crucial for efficient biogas generation.

Purpose of the Study:

• * To evaluate the efficacy of mixed inocula from different waste treatment plants for biogas production.
• * To determine the optimal combination of inocula for maximizing biogas and methane yield.
• * To compare the performance of mixed inocula against control sources.

Main Methods:

• * Inocula were sourced from a tannery waste treatment plant (ITW), municipal waste treatment (IMW), a distillery (IDW), and a batch reactor with cow dung slurry (IBS).
• * Mixed inocula combinations were tested in laboratory-scale reactors (10 L) at 35°C for 41 days.
• * Biogas and methane yields (L/g volatile solid) and methane content (%) were measured.

Main Results:

• * The mixed inoculum IMW(1) (IMW+IBS) demonstrated superior performance, yielding 0.547 L biogas/g VS and 0.323 L methane/g VS.
• * This combination also achieved the highest methane content in biogas at 68% during days 27-30.
• * Other mixed inocula (ITW(1), IDW(1)) and the control (IBS) showed lower biogas and methane yields.

Conclusions:

• * Combining municipal waste treatment (IMW) inoculum with biogas reactor sludge (IBS) significantly enhances biogas and methane production.
• * This optimized inoculum strategy offers a promising approach for efficient biogas generation from waste resources.
• * The findings highlight the importance of inoculum source selection in anaerobic digestion processes.