CHARACTERISTICS OF TEMPERATURE CHANGE ON THE SUBSTRATE DEGRADATION AND BACTERIAL POPULATION IN ONE-PHASE AND TWO-PHASE ANAEROBIC DIGESTION

Cha, Gi-Cheol; Chung, Hyung-Keun; Kim, Dong-Jin

Environmental Engineering Research 2001;6(2): 99-108.

Gi-Cheol Cha¹^†, Hyung-Keun Chung¹, and Dong-Jin Kim²

¹Department of Environmental Engineering, Yonsei University, Wonju 220-710, Korea
²Department of Environmental Science, Hallym University, Chunchon 200-702, Korea

Corresponding Author: Gi-Cheol Cha ,Tel: +82-33-760-2450, Fax: +82-33-763-5224, Email: gccha@dragon.yonsei.ac.kr

Received: February 23, 2001; Accepted: May 22, 2001.

ABSTRACT

The effects of rapid temperature change on the characteristics of substrate degradation and bacterial population in one-phase and two-phase anaerobic digestion processes were investigated using anaerobic chemostat-type reactors fed with soluble starch as a substrate. The digesters had been maintained more than 6 months at 30 °C prior to changing to 20 °C, and the temperature was decreased to 20 °C over 8 hours after a steady state conditions and thereafter maintained at 20 °C. The degradation efficiencies of the substrate decreased by approximately 4% after 5 days in one-phase anaerobic digester and approximately 20% after 7 days in the acidogenic phase of two-phase anaerobic digester, but no significant impact was observed in the methanogenic phase. The change in temperature did not have a significant impact on the bacterial population levels in one-phase anaerobic digester. In two-phase anaerobic digester, however, the number of acetate-utilizing methanogenic bacteria significantly decreased, but no impact was observed on acidogenic bacteria and H₂-utilizing methanogenic bacteria.

Keywords: acidogenesis | anaerobic reactor | bacterial population | methanogenesis | rapid temperature change