초음파 전처리를 이용한 하수슬러지의 혐기성 소화성능 비교 평가

In this study, pilot scale anaerobic digester was performed with and without ultrasonic pretreatment to evaluate treatment of sewage sludge. The substrate was used via mixing raw and excess sludge by ratio 3 : 7. The operating conditions were ultrasonic irradiation intensity 64 W/L, irradiation time 1 hour, HRT 20 days. Two parallel anaerobic digesters of 3 m3 working volume each were operated for 200 days. The biogas and methane yield were estimated as 0.27 m3/kg COD and 0.19 m3/kg COD, respectively, for the ultrasonicated sludge, which were improved compared to 0.22 m3/kg COD and 0.13 ㎥/kg COD, respectively, for the control. In addition, the average methane content of the biogas was 69.2 % for the ultrasonicated, which was 10.4 % higher than that of the control. The long-term, continuous operation was considered very stable by evaluating parameters such as TS, VS, pH, Alkalinity, organic acids, etc.