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Evaluation of silage-fed biogas process performance using microbiological and kinetic methods

Abstract

In this study, different kinetic and microbiological methods were used to evaluate the growth and activity of key groups of bacteria degrading ley silage in one-phase and two-phase biogas processes. Emphasis was placed on studying the dynamic behaviour of different trophic groups resulting from the initiation of liquid recirculation in the processes. The microbiological methods included microscopy and most probable number (MPN) counts with different substrates. The kinetic methods included measurements of specific methanogenic activity (SMA) with acetate and H{sub 2}/CO{sub 2} as substrates, batch assays with trace element additions and measurement of conversion rates of mannitol and lactate in the digesters. In general, the initiation of liquid recirculation at first promoted the growth and/or activity of several trophic groups of bacteria, such as butyrate and propionate degraders and acetotrophic and hydrogenotrophic methanogens in the liquefaction/acidogenesis reactors of the two-phase processes. This was probably mainly due to the increased pH. However, after some time of liquid recirculation, an inhibition of some bacterial groups occurred, such as propionate degraders and methanogens in the methanogenic reactors of two-phase processes. This was probably due to increased concentrations of salts and free ammonia. The batch assays proved to be valuable tools in process optimization  More>>
Authors:
Publication Date:
Oct 01, 1996
Product Type:
Thesis/Dissertation
Report Number:
SLU-MIKRO-R-63
Reference Number:
SCA: 090900; PA: SWD-96:007485; EDB-96:141614; NTS-97:002139; SN: 96001663841
Resource Relation:
Other Information: TH: Diss (AgrD); PBD: 1996
Subject:
09 BIOMASS FUELS; METHANE; DECOMPOSITION; METHANOGENIC BACTERIA; GROWTH; COBALT; BIOMASS; BIOGAS PROCESS; CLOVER; GRAMINEAE
OSTI ID:
371275
Research Organizations:
Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Microbiology
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0348-4041; Other: ON: DE97700144; TRN: SE9607485
Availability:
OSTI as DE97700144
Submitting Site:
SWD
Size:
59 p.
Announcement Date:

Citation Formats

Jarvis, Aa. Evaluation of silage-fed biogas process performance using microbiological and kinetic methods. Sweden: N. p., 1996. Web.
Jarvis, Aa. Evaluation of silage-fed biogas process performance using microbiological and kinetic methods. Sweden.
Jarvis, Aa. 1996. "Evaluation of silage-fed biogas process performance using microbiological and kinetic methods." Sweden.
@misc{etde_371275,
title = {Evaluation of silage-fed biogas process performance using microbiological and kinetic methods}
author = {Jarvis, Aa}
abstractNote = {In this study, different kinetic and microbiological methods were used to evaluate the growth and activity of key groups of bacteria degrading ley silage in one-phase and two-phase biogas processes. Emphasis was placed on studying the dynamic behaviour of different trophic groups resulting from the initiation of liquid recirculation in the processes. The microbiological methods included microscopy and most probable number (MPN) counts with different substrates. The kinetic methods included measurements of specific methanogenic activity (SMA) with acetate and H{sub 2}/CO{sub 2} as substrates, batch assays with trace element additions and measurement of conversion rates of mannitol and lactate in the digesters. In general, the initiation of liquid recirculation at first promoted the growth and/or activity of several trophic groups of bacteria, such as butyrate and propionate degraders and acetotrophic and hydrogenotrophic methanogens in the liquefaction/acidogenesis reactors of the two-phase processes. This was probably mainly due to the increased pH. However, after some time of liquid recirculation, an inhibition of some bacterial groups occurred, such as propionate degraders and methanogens in the methanogenic reactors of two-phase processes. This was probably due to increased concentrations of salts and free ammonia. The batch assays proved to be valuable tools in process optimization by the addition of trace elements. Here, the addition of cobalt significantly increased methane production from acetate. In this study, a more comprehensive understanding of the process behaviour in response to the initiation of liquid recirculation was achieved which could not have been obtained by only monitoring routine parameters such as pH, methane production and concentrations of organic acids and salts. 120 refs, 4 figs, 1 tab}
place = {Sweden}
year = {1996}
month = {Oct}
}