Single-Stage And Double-Stage Digesters

[Haya]

What is the difference between the single-stage digester and the two-stage digester?

[exchemist]

What is the difference between the single-stage digester and the two-stage digester?

In what context?

[Haya]

In what context?

In the anaerobic digestion; there are two types of digesters: single-stage digesters and double-stage digesters.

What is the difference between both of them?

[exchemist]

In the anaerobic digestion; there are two types of digesters: single-stage digesters and double-stage digesters.

What is the difference between both of them?

I assume you are talking about biogas generation. Is that correct?

 

If so, then I found this link which is quite helpful: http://www.americanbiogascouncil.org/biogas_what.asp

 

It seems that the initial steps of digestion involve generation of acid species, whereas the final stage, which is generation of methane by methanogenic bacteria, can be limited by the level of acidity (low pH)  that methanogens can tolerate. The 2 stage process allows the generation of methane to take place in a separate unit from the earlier stages, so that the acidity can be controlled to optimise the growth of these methanogens. This apparently permits a more rapid throughput of organic waste. The trade-off is the increased complexity of the arrangement, compared to a single stage digestion process.

 

That, at any rate, would be my summary of what I have read. I do not pretend to be an expert on this topic. 

[Haya]

I assume you are talking about biogas generation. Is that correct?

 

If so, then I found this link which is quite helpful: http://www.americanbiogascouncil.org/biogas_what.asp

 

It seems that the initial steps of digestion involve generation of acid species, whereas the final stage, which is generation of methane by methanogenic bacteria, can be limited by the level of acidity (low pH)  that methanogens can tolerate. The 2 stage process allows the generation of methane to take place in a separate unit from the earlier stages, so that the acidity can be controlled to optimise the growth of these methanogens. This apparently permits a more rapid throughput of organic waste. The trade-off is the increased complexity of the arrangement, compared to a single stage digestion process.

 

That, at any rate, would be my summary of what I have read. I do not pretend to be an expert on this topic.

 

Thank you!