젖소분뇨의 혐기성 소화 효율 향상을 위한 마이크로파-알칼리 전처리 효과: 메탄 생성 및 생분해도

Effect of Microwave-Alkali Pretreatment on the Anaerobic Digestion Efficiency of Dairy Manure: Methane Production and Biodegradability

Fufa Abera Jabessa1, 이승훈2, Wardhani Riuh1, 송용우3, 신진호2, 박성준3, 김동여3, 안희권1,3,4*

Abera Jabessa Fufa1, Seunghoon Lee2, Riuh Wardhani1, Yongwoo Song2, Jinho Shin1, Seongjun Park2, Dongyeo Kim2, Heekwon Ahn1,3,4*

1충남대학교 낙농학과, 2충남대학교 농업과학연구소, 3충남대학교 축산환경학과, 4충남대학교 동물바이오시스템과학과

1 Dept. of Dairy Science, Chungnam National University, Daejeon, Korea

2Institute of Agricultural Science, Chungnam National University, Daejeon, Korea

3Dept. of Livestock Environment Science and Technology, Chungnam National University, Daejeon, Korea

4Dept. of Animal Biosystems Science, Chungnam National University, Daejeon, Korea

*교신저자: 안희권*(hkahn@cnu.ac.kr)

Enhancing the anaerobic digestibility of dairy manure remains a significant challenge as a result of the recalcitrant structure of lignocellulosic content, which limits the solubilization and subsequent methane production. This study aimed to evaluate the effect of microwave-alkali pretreatment on the methane yield potential and biodegradability of raw dairy manure under anaerobic digestion conditions. Six treatment groups were evaluated over a 26-day hydraulic retention time (HRT) at mesophilic temperature 37+1oC, including: C01 (control), T01 (microwave only), T02 (3% NaOH), T03 (6% NaOH), T04 (3% NaOH + microwave), and T05 (6% NaOH+ microwave). An inoculum-only group was included to estimate background methane production. Dairy manure and inoculum were mixed at a 1:1 ratio based on volatile solids (VS), and the NaOH was added based on total solids (TS). The sample was heated from an initial temperature of 20 °C to a target of 90 °C using a standard household microwave oven operating at 2.45 GHz and 700 W. The heating duration was 5 minutes, corresponding to an average temperature increase rate of 14oC/min. Among the treatments, T05 achieved the highest statistically significant improvements over the control in cumulative methane yield and biogas production, reaching 222.1 mL CH4/g VS and 363.0 mL biogas/g VS, respectively (p<0.05). In the control group, the cumulative methane yield was 185.5 CH₄ mL/g VS, and biogas production was 316.00 mL/g VS. Volatile solids reduction efficiency (36.69%), volatile dissolved solid removal efficiency (48.5 %), COD removal efficiency (37.6%), ultimate biodegradability (42.45%) and methane efficiency (65.68%) observed in T05 further support the enhanced biodegradation of volatile organic matter into soluble and bioavailable forms. The improved performance in T05 suggests that the synergetic effect of microwave-alkali pretreatment effectively disrupted lignocellulosic structures, enhancing the solubilization and bioavailability of organic matter. Overall, the combined microwave-alkali pretreatment, particularly with 6% NaOH, represents a promising strategy for improving the anaerobic biodegradability of dairy manure and maximizing methane yield.

*키워드(Keywords): Anaerobic digestion, Dairy manure, Microwave-alkali pretreatment, Methane yield, Biodegradability

*사사(Acknowledgment): Livestock Environmental laboratory, Chungnam National University; and Global Korea Scholarship (GKS) Program