Evaluating Feeding of Organic Waste and Stirring Interval to Optimize Anaerobic Digestion

초록

Purpose: In the process of anaerobic digestion, stirring of the digester and feeding of organic waste into the digester havebeen considered important factors for digestive efficiency. The objective of this study was to determine the mostappropriate conditions for both stirring interval of the digester and organic feeding frequency in order to improve anaerobicdigestion performance. Methods: A 5-L anaerobic digester was used to conduct continuous batch tests to process swinemanure and food waste. Four different stirring intervals of the digester were used: 5 min/h, 10 min/2 h, 15 min/3 h, and 20min/4 h. Results: The application of swine manure to the digester every 5 min/h resulted in the highest production of biogasas well as the highest removal rates of volatile solids (VS) and total chemical oxygen demand. Stirring the digester with amixture of swine manure and food waste at intervals of 5min/h and 10min/2 h produced the highest biogas yields of 515.3mL/gVS and 521.1 mL/gVS, respectively. To test different supply frequencies, organic waste was added to the digester ineither a 12-hor 24-h cycle. The 24-h cycle produced 1.5-fold greater biogas production than that during the 12-h cycle. Conclusions: Thus, from the above results, to optimize anaerobic digestion performance, the ideal stirring condition must be5min/h for swine manure feeding and 10min/2h for co-digestion of food waste and swine manure in a 24-h cycle.

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