Improvement of biohydrogen production from solid wastes by intermittent venting and gas flushing of batch reactors headspace.

Full Abstract

Headspace of batch minireactors was intermittently vented and gas flushed with N2 in order to enhance H2 production (PH) by anaerobic consortia degrading organic solid wastes. Type of inocula (meso and thermophilic), induction treatment (heat-shock pretreatment, HSP, and acetylene, Ac), and incubation temperature (37 and 55 degrees C) were studied by means of a factorial design. On average, it was found that mesophilic incubation had the most significant positive effect on PH followed by treatment with Ac, although the units with the best performance (high values of PH, initial hydrogen production rate, and short lag time) were those HSP-induced units incubated at 37 degrees C (type of inocula was not significant). In this way, after 720 h of incubation PH was inhibited in those units by H2 partial pressure (pH2) of 0.54 atm. Venting and gas flushing with N2 was efficient to eliminate that inhibition achieving additional hydrogen generation in subsequent incubation cycles although smaller than the first one. Thus, four cycles of PH were obtained from the same substrate with neither addition of inocula nor application of induction treatment obtaining an increment of 100% in the generated H2. In those subsequent cycles there was a positive correlation between PH and organic acids/solvent ratio; maximum values were found in the first cycle. Solventogenesis could be clearly distinguished in third and fourth production cycles, probably due to a metabolic shift originated by high organic acid concentrations.

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Author information

Author/s: Valdez-Vazquez, Idania (I); Ríos-Leal, Elvira (E); Carmona-Martínez, Alessandro (A); Muñoz-Páez, Karla M (KM); Poggi-Varaldo, Héctor M (HM);

Affiliation: CINVESTAV-IPN, Department of Biotechnology and Bioengineering, Environmental Biotechnology R&D Group, P.O. Box 14-740, Mexico D. F., 07000, Mexico.

Journal and publication information

Publication Type: Journal Article

Journal: Environmental science & technology (Environ Sci Technol), published in United States. (Language: eng)

Reference: 2006-May; vol 40 (issue 10) : pp 3409-15

Dates: Created 2006/06/05; Completed 2006/10/03;

PMID: 16749714, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Acids - isolation & purification; metabolism
Anaerobiosis
Biomass
Bioreactors
Hydrogen - chemistry; metabolism
Hydrogen-Ion Concentration

Industrial Waste
Nitrogen - chemistry
Organic Chemicals - isolation & purification; metabolism
Refuse Disposal - methods
Temperature
Waste Disposal, Fluid

Associated Chemicals: Acids (0) ; Industrial Waste (0) ; Organic Chemicals (0) ; Hydrogen (1333-74-0) ; Nitrogen (7727-37-9)

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