극초단파 전처리를 적용한 하수슬러지 혐기성소화에서 메탄수율 최적화

초록

The objective of this study was to find an optimum methane yield condition in anaerobic digestion of sewage sludge with microwave pretreatment. The pretreatment process was carried out using a lab scale industrial microwave unit (2,450 MHz frequency). The digestion efficiency of pretreatedsludge was evaluated by biochemical methane potential (BMP) test. Box-Behnken design and Response Surface Analysis (RSA) were applied todetermine the optimal combination of sludge mixing ratio (0 to 100%), power (400 to 1600 W), holding time (0 to 10 min) and pretreatmenttemperature (60 to 100℃). BMP test results showed that Volatile Solid (VS) removal efficiency was up to 48% at a condition of 0% for mixingratio, 1600 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. Methane production was up to 832.3 mL/g VSremoved ata condition of 50% for mixing ratio, 1000 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. The results of the varianceanalysis (ANOVA) showed that the p-value of the power and pretreatment temperature among the independent variables were significant (p<0.05),and in particular, the pretreatment temperature significantly affected on the solubilization and methane production. The optimum condition for themaximum methane yield (847 mL/g VSremoved) was consist of 38.4% of mixing ratio, 909.1 W of power, 4.1 min of holding time, and 80℃ oftemperature within the design boundaries.

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