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Dissolved hydrogen concentration as an on-line control parameter for the automated operation and optimization of anaerobic digesters

Cord-Ruwisch, R., Mercz, T.I., Hoh, C-Y and Strong, G.E. (1997) Dissolved hydrogen concentration as an on-line control parameter for the automated operation and optimization of anaerobic digesters. Biotechnology and Bioengineering, 56 (6). pp. 626-634.

Link to Published Version: http://dx.doi.org/10.1002/(SICI)1097-0290(19971220...
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Abstract

The use of dissolved hydrogen as an early warning signal of digester failure and a control parameter to operate anaerobic digesters was investigated. A sensitive, on-line method was developed for measuring trace levels of dissolved hydrogen in a semi-permeable membrane, situated within the biomass of a 1 L laboratory anaerobic digester, using trace reduction gas analysis. At normal operating conditions, the dissolved hydrogen partial pressure (2 to 8 Pa) was found to be linearly correlated with the loading rate of the digester, and was a sensitive indicator of the effect of shockloads as well as gradual overloading. An increase in hydrogen partial pressure above a critical concentration of 6.5-7 Pa indicated the initial stage of digester overloading (i.e., volatile fatty acids accumulation). A H2-based computer control system, using a critical hydrogen partial pressure of 6.5 Pa as the setpoint, was found to be effective for the safe operation of a laboratory digester close to its maximum sustainable loading rate. The existence of a relationship between hydrogen level and organic loading rate was also confirmed on a 600 m3 industrial digester, with digester overloading occurring at hydrogen concentrations above 7 Pa. The results suggest that the dissolved hydrogen concentration is capable of being a sensitive on-line parameter for the automated management of anaerobic digesters near their maximum sustainable loading capacity.

The use of dissolved hydrogen as an early warning signal of digester failure and a control parameter to operate anaerobic digesters was investigated. A sensitive, on-line method was developed for measuring trace levels of dissolved hydrogen in a semi-permeable membrane, situated within the biomass of a 1 L laboratory anaerobic digester, using trace reduction gas analysis. At normal operating conditions, the dissolved hydrogen partial pressure (2 to 8 Pa) was found to be linearly correlated with the loading rate of the digester, and was a sensitive indicator of the effect of shockloads as well as gradual overloading. An increase in hydrogen partial pressure above a critical concentration of 6.5-7 Pa indicated the initial stage of digester overloading (i.e., volatile fatty acids accumulation). A H2-based computer control system, using a critical hydrogen partial pressure of 6.5 Pa as the setpoint, was found to be effective for the safe operation of a laboratory digester close to its maximum sustainable loading rate. The existence of a relationship between hydrogen level and organic loading rate was also confirmed on a 600 m3 industrial digester, with digester overloading occurring at hydrogen concentrations above 7 Pa. The results suggest that the dissolved hydrogen concentration is capable of being a sensitive on-line parameter for the automated management of anaerobic digesters near their maximum sustainable loading capacity.

Item Type: Journal Article
Publisher: Wiley - V C H Verlag GmbbH & Co
Copyright: © 1997 John Wiley & Sons, Inc.
Publishers Website: http://onlinelibrary.wiley.com/journal/10.1002/%28...
URI: http://researchrepository.murdoch.edu.au/id/eprint/8665
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