[Digestion] Biogas production in batch digester

[Markus Schlattmann]

Hi,
> It is well known that batch digestion does not produce the same amount 
> of biogas every day. Obviously it takes some time for the ecology of 
> the digester to get established (during which time, of course, gas 
> production is low), and it is surely something approaching a law of 
> biology that the more digestible components of the substrate will be 
> used up first, and then some of the more recalcitrant materials will-- 
> eventually-- be digested. The succession of these stages offers a 
> well-known curve, which is either bell-shaped, if it plots daily 
> production, or a long S (ogee) curve if we are plotting cumulative 
> production.
>
> -- 
> David William House
> "The Complete Biogas Handbook" |www.completebiogas.com|
> /Vahid Biogas/, an alternative energy consultancy |www.vahidbiogas.com
>
> |
>

Yes, this is also my experience. And if you have already an active 
microbial population in the beginning (e.g. taking digestate of an 
active digester as an inoculum), the gas production starts quickly.
For having a look at some data, I just added 2 old plots to my webpage, 
one showing the "bell shape" (upper image), the other the "S curve" 
(lower image).:
http://www.schlattmann.de/biogas/3-substrate/biogas3-batch-test.php

Most of the gas in batch operation is produced in the first 2 weeks, 
after that it keeps long at a low level.

-- 
Mit freundlichen Grüßen
Markus Schlattmann

--------------------------------------
schlattmann sustainables
schlattmann.de

Dipl.-Ing. agr. Markus Schlattmann
Grünseiboldsdorfer Weg 5
85416 Langenbach

Tel.: +49 (0)8761 72162-60
Fax.: +49 (0)8761 72162-61

E-Mail: firmen at schlattmann de
Web: www.schlattmann.de
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