Seaweeds are received high attending as one of new and renewable energy sources. In this study, the effects of organic loading rate (OLR) and hydraulic retention time (HRT) on anaerobic digestion with Laminaria japonica were investigated using labrotory-scale semi-continuous stirred type reactors. The results demonstrated that anaerobic digestion of Laminaria japonica performed stably with OLRs in the range of 1.00 ~ 1.50 g-VS/L⋅d and HRTs in the range of 27 ~ 40 days. The maximum methane production obtained was 251.33 mL-CH4/L⋅d, which was achieved for an OLR of 1.50 g-VS/L⋅d and a HRT of 27 days. However, an OLR of 1.75 g-VS/L⋅d and a HRT of 23 days brought about a decrease in the pH and volatile fatty acids (VFAs) accumulation, causing the destabilization of the reactor and process failure. The reactors operated at a constant influent substrate concentration, i.e., 40 g-VS/L, thus OLR and HRT could not be treated separately and independently. According to the limited results of this study, it seems that the suitable OLR of anaerobic digestion of Laminaria japonica was lower than 1.50 g-VS/L⋅d and suitable HRT was higher than 27 days.

Abstract
 I. 서 론
 II. 실험 재료 및 방법
  1. 반응조 운전
  2. 분석 방법
 III. 결과 및 고찰
  1. 메탄발생량
  2. VFAs 농도
  3. COD 제거율
 IV. 결 론
 사 사
 References

• Zheng Hua Piao(서울대학교 공과대학 건설환경공학부)
• Xin Zhao(서울대학교 공과대학 건설환경공학부)
• 이종근(서울대학교 공과대학 건설환경공학부) | Jong-Keun Lee
• 김재영(서울대학교 공과대학 건설환경공학부) | Jae Young Kim Corresponding author