Anaerobic digestion: Method comparisons

Within the field of anaerobic digestion there are a number of different methods for producing biogas. The first part of this page compares the two main methods. The second part of the page compares the 3-step Aikan with other methods that are optimized for handling of solid organic waste.

Main methods: Wet AD and Dry AD

Anaerobic digestion turns organic waste into useful biogas and fertilizer in an environment with little or no oxygen. The two main methods used have become known as dry anaerobic digestion (Dry AD) and wet anaerobic digestion (Wet AD).

The main difference between to two methods relates to the form of the solid waste. Dry AD handles organic waste more or less as it is, using only simple mechanical sorting and with digestion taking place from waste in its solid form. Wet AD requires ¬that the waste be turned into a homogenous pulp that can be pumped while being processed.

Both Wet AD and Dry AD take place in a wet environment, so for new-comers the terminology can be a little confusing.

Both types of anaerobic digestion rely on the same organic processes: hydrolysis, methane generation and composting of the solid fraction. The Wet AD and Dry AD approaches differ with regards to how waste is processed and what qualities of waste can be treated.

Historically, attempts have been made to apply the Wet AD method to Municipal Solid Waste (MSW). Many of these attempts have failed due to problems with high levels of impurities in MSW.

Aikan Technology uses the Dry AD method in a unique 3-step process which allows for the solid waste to remain untouched inside the process module during methanation and composting.


Comparison of Aikan Technology and other Dry AD systems

The following table shows a comparison between Aikan Technology and other Dry AD processing methods currently available on the market.