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Dissolved hydrogen concentration as an on‐line control parameter for the automated operation and optimization of anaerobic digesters
Author(s) -
CordRuwisch Ralf,
Mercz Tom I.,
Hoh ChoonYee,
Strong Grahame E.
Publication year - 1997
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19971220)56:6<626::aid-bit5>3.0.co;2-p
Subject(s) - hydrogen , setpoint , anaerobic digestion , anaerobic exercise , chemistry , environmental science , partial pressure , pulp and paper industry , environmental chemistry , oxygen , methane , organic chemistry , computer science , biology , engineering , physiology , artificial intelligence
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 H 2 ‐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 m 3 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. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 626–634, 1997.