Apr 14, 2021
Methane fermentation is a biological process in which anaerobic microorganisms break down organic matter to generate methane gas, enabling energy production from sources such as sewage sludge and food waste. There are several types of methane fermentation, including wet and dry fermentation, as well as mesophilic and thermophilic processes—each with distinct characteristics and operational considerations. Yanmar offers biogas power generation systems and supports the efficient utilization of biomass resources.
Methane fermentation is a process in which methanogens—anaerobic microorganisms—break down organic matter in an oxygen-free environment to produce methane, a combustible gas. This process enables the generation of energy from biomass resources such as sewage sludge, livestock manure, and food waste.
Because these biomass resources are carbon neutral—releasing no additional CO2 into the atmosphere—they are considered effective in mitigating global warming. Methane fermentation is also expected to promote local energy production and consumption, as well as the circulation of resources within local communities.
Wet fermentation involves adjusting the solids concentration in the tank to 10 % or less and continuously stirring the mixture to produce methane. To retain methanogens, techniques such as the floating method, fixed-bed method, fluidized-bed method, and UASB (upflow anaerobic sludge blanket) method are used.
Dry fermentation, on the other hand, operates with a solids concentration of 15–40 % and can process harder-to-handle materials like pruned branches and paper waste. However, it is harder to control, as limited fluidity restricts the movement and dispersion of substrates and microbes. This can cause localized reactions and hinder microbial cooperation, which is essential for breaking down organic matter and producing methane.
Some methanogens thrive at moderate temperatures (30–37 °C), while others prefer higher temperatures (50–55 °C). Fermentation tanks must be kept within one of these ranges. High-temperature methanogens, however, have a narrower tolerance, requiring stricter temperature control.
Chemical reactions generally double in speed with every 10 °C rise, making high-temperature fermentation more efficient. However, it also demands more heat energy.
Yanmar Energy System supplies biogas power systems across Japan using sewage sludge and food waste. We offer tailored solutions for effective biomass utilization. Feel free to contact us for more information.