Influence of the VS-content in digested sludge on the
anaerobic degradation of organic substrates at same loading rates [g/g]
Introduction:
In
this study the influence of the content of volatile solids (= VS-content)
[g/kg] in digested sludge on the anaerobic degradation of organic substrates
was determined by varying the VS-content in the digested sludge for the
batch-experiments by its dilution with tap-water.
As
organic substrates cellulose, casein and olive oil and their mixtures in
different compositions have been anaerobicaly degraded for a period of 21 days
at a temperature of 35°C with digested sludge.
However,
for each anaerobic degradation experiment the loading rate [g/g] (synonymous to
the ratio of organic input-substrate and VS-content in the digested sludge) was
set at 0,55 [g/g].
Result:
The VS-content in the digested
sludge influences the anaerobic degradation: at the same loading rate of 0,55
[g/g] in all batch-experiments the biogas yields while the anaerobic
degradation of mono-substrates and substrate-mixtures are lower with low
VS-content in the digested sludge than the biogas-yields reached with higher
VS-content in the sludge. This statement can be confirmed by the DNA-
determination and the calculated amounts of living microorganism in reliance to
the VS-content in the sludge.
Origin:
R. Mundhenke, J.Müller, J. Schwedes
(2001). Influence
of the VS-content in digested sludge on the anaerobic degradation, Chem. Eng.
Technol., Vol. 24, No.6, pp 635-637