Comparison of one-phase and two-phase anaerobic digestion processes in characteristics of substrate degradation and bacterial population levels

T. C. Zhang, T. Noike

Research output: Chapter in Book/Report/Conference proceedingConference contribution

50 Scopus citations

Abstract

The comparison of one-phase and two-phase anaerobic digestion processes in the characteristics of substrate degradation and the bacterial population levels was investigated by using the chemostat-type reactors to which starch was fed as substrate when both processes were operated under the same experimental conditions. By decreasing the SRTs of both systems from 10.2 d to 5 d, 2.5 d and 1.75 d, it was found that the two-phase system was more stable to the change in pH than one-phase system. The CH4 recovery rates and COD removal rates in the two-phase system increased by 4 to 9% and 3 to 10%, respectively, although the CH4 recovery rate and the COD removal rate in the one-phase system were slightly higher than those in the two-phase system at the SRT of 10.2 d. The concentration of propionate in the effluent of the one-phase system was 30 to 50% higher than in the two-phase system: while the concentrations of acetate and butyrate in the one-phase system were slightly lower than those in the two-phase one. The enumeration of the bacteria was performed by the MPN method. The population levels of acidogenic bacteria in both systems were in the same order (108 to 1010 MPN/ml), the population levels of hydrogenotrophs were also in the same order as the acidogenic bacteria in the two-phase system, while the population levels of hydrogenotrophs were 10 to 100 fold less than that of acidogenic bacteria in the one-phase system. The number of HAc-utilizing methanogens in the methanogenesis of the two-phase system were 2 to 10 times higher than that in the one-phase system. Therefore, the one-phase system cannot be regarded simply as the sum of acidogenesis and methanogenesis.

Original languageEnglish (US)
Title of host publicationWater Science and Technology
Pages1157-1166
Number of pages10
Volume23
Edition7-9
DOIs
StatePublished - 1991
Externally publishedYes
EventProceedings of the 15th Biennial Conference of the International Association on Water Pollution Research and Control - Kyoto, Jpn
Duration: Jul 29 1990Aug 3 1990

Other

OtherProceedings of the 15th Biennial Conference of the International Association on Water Pollution Research and Control
CityKyoto, Jpn
Period7/29/908/3/90

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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