Different kinds of substrates you can produce different amounts of biogas and have different rates of degradation. They know some method to determine these rates?
A common technique to determine the DM content is by oven-drying.
This is a very simple and robust method where water is evaporated and the dry matter of the sample remains. However, a disadvantage of the method is that volatile molecules (in addition to water) are lost during the drying. Volatile substances include among others, volatile fatty acids (VFAs) and alcohols. This may result in an underestimation of the DM content, and subsequently also an underestimation of the VS content. Consequently, this will result in errors in all the parameters that are calculated based on DM and VS.
Consequently,determination quantification of the evaporation of VFA from substrates and digestates during DM-analysis are therefore of greatest importance.
Method for correction of VFA loss in determination of dry matter in biomass:
http://www.sgc.se/ckfinder/userfiles/files/SGC273.pdf
Materials left after evaporation is the dry matter , while loss in weight upon ignition at certain defined temperature is the organic matter content ..In a way ...“Dry matter is determined by drying sample for 15h at 105°C and organic matter by ashing for at least 4h at 500°C.”
Dear Jose,
(1) Dry matter % in the substrate must be determined as quickly as possible to limit the losses through evaporation. The standardised method consists of a levy of a maximum quantity of sample, preferably a mass greater than 100+0.1 g, placing in the oven at 105+2 0C until constant weight, for approximately 24 hours.
(2) For determining dry volatile matter, a mass around 50+0.1 g is placed at 550 0C, for 2 hours in a furnace.
For your reference and use, I attach herewith PDF of a research paper by Laskri N, Hamdaoui O and Nedjah N (2015) Journal of Clean Energy Technologies 3(3):181-184.
I hope you find the input useful.
Dry matter (DM) is that which remains after redrying at 105°C for 15h a previously dried and ground sample. Dry matter is expressed as a percentage of the sample at the time of the analysis.
Organic Matter is the loss in weight of DM after 15h at 550°C expressed as a percentage of DM.
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