Time Variation Modeling and Trend Analysis of the Biogas Production Using Geostatistic

Biogas production from anaerobic digestion of livestock manure is one of valuable energy resources. The use of stirrer and mixing of substrate can improve biogas production rate in digesters. Present research was carried out in order to model and trend analysis of biogas production and mixing effect in a full scale batch reactor 1200 lit. With liquid volume of 800 lit using geostatistic. Variograms were used for modeling biogas production in three states: (I) without stirring and (II), (III) stirring at 40 and 100 rpm, respectively. Then, the proposed models were evaluated by reproducing observed data using kriging. Cross validation and statistical indices such as determination coefficient and remaining sum of squares were the assessment criterion. Simulation results showed that biogas production trend under uniform flow condition had most data structural continuity with correlation of 0.97 and in state of (III) with correlation of 0.33 had the lowest data structural continuity.