Underestimation of Dry Matter of Anaerobic Media with High Bicarbonate Concentration

In the anaerobic digestion world, dry matter (DM) and organic (OM) contents of samples are major data for design, handling, maintenance processing biogas plants. Volatile compounds, such as volatile fatty acids ammonia, likely to volatilize during drying at 105 °C and, thus, distort DM values; they have been described length in literature. On other hand, partial decomposition bicarbonate, present media, has little scientific this work, it appears that, accordance with stoichiometry bicarbonate into CO2 H2O, about 37% is volatilized early 70 a fortiori °C, whether aqueous solutions pure or different real digester media. With freeze-drying, no degradation was observed, confirming thermo-dependence reaction. This leads an underestimation measurements some erroneous mass balances. It also led indirect overestimation OM, when expressed percentage DM.