measured. They can represent an important fraction of wastewaters. The total solid
content is used to understand if the feedstock contains sufficient moisture. If the
moisture content (which is complementary to 100% to the solids content) is low,
dilution has to be performed using the following:
– Fresh water
– Adding other more liquid feedstocks
– Recycling part of the digestate or its liquid fraction, once the solid–liquid
separation has been performed
If the liquid content is too high, this will mean that too few nutrients are fed to the
biogas reactor which will not work in an efficient way.
For calculating the amount of organic matter in the raw material, the volatile
solids (expressed in %) or organic dry matter (expressed in g/l) should be determined. This determination is usually carried out using a thermogravimetric balance
(see Fig. 10.3) (The related standards are EN 12879 (2000) and APHA 2540 E (2540
SOLIDS 2017)). Obviously, in this measurement are not counted the low molecular
weight organic compounds which evaporate during drying.
Fig. 10.3 TGA diagram which highlighted the main biomass components (El-Sayed and Mostafa
2014)
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content is used to understand if the feedstock contains sufficient moisture. If the
moisture content (which is complementary to 100% to the solids content) is low,
dilution has to be performed using the following:
– Fresh water
– Adding other more liquid feedstocks
– Recycling part of the digestate or its liquid fraction, once the solid–liquid
separation has been performed
If the liquid content is too high, this will mean that too few nutrients are fed to the
biogas reactor which will not work in an efficient way.
For calculating the amount of organic matter in the raw material, the volatile
solids (expressed in %) or organic dry matter (expressed in g/l) should be determined. This determination is usually carried out using a thermogravimetric balance
(see Fig. 10.3) (The related standards are EN 12879 (2000) and APHA 2540 E (2540
SOLIDS 2017)). Obviously, in this measurement are not counted the low molecular
weight organic compounds which evaporate during drying.
Fig. 10.3 TGA diagram which highlighted the main biomass components (El-Sayed and Mostafa
2014)
314
PietroBartocci et al.