Influence of C/N and C/P ratio in hydrogen production in anaerobic fluidized bed reactor

Author(s)

Mariana Fronja Carosia

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
• Defense date: 2014-08-14

Examining board members

Edson Luiz Silva; Marcelo Loureiro Garcia; Simone Damasceno Gomes; Sandra Imaculada Maintinguer; Marcelo Zaiat

• Advisor: Edson Luiz Silva

Abstract

The aim of this study was to evaluate the influence of the carbon/nitrogen (C/N) and carbon/phosphorus (C/P) ratio in hydrogen (H2) production in anaerobic fluidized bed reactor (AFBR) containing grounded tire as support material for microbial adhesion. Synthetic substrate containing glucose (5,000 mg L-1) was used as the carbon source, and the effluent pH remained ±3.7. Four reactors were operated with C/N=100 (R1), C/N=150 (R2), C/N=200 (R3) and C/N=250 (R4), under mesophilic conditions. The reactors were operated for 18 months and the experiment was divided into three phases: in the 1st Phase, the C/P ratio was maintained at the value of 300 and hydraulic retention time (HRT) was varied in 8, 6, 4, 2 and 1 h; in the 2nd phase, the HRT was kept at 2 h and the C/P ratio was varied in 300, 500, 700, 900 and 1100; and in the 3rd Phase, the HRT was kept at 8 h and C/P ratio varied in the values of 300, 500, 700, 900 and 1100. The highest values of hydrogen production (HPR) were obtained in R3 (C/N=200), HRT of 2 h and C/P=700 (0.70 L.h-1.L-1) and they were related to fermentative pathways of ethanol and acetic acid production. The highest values of hydrogen yield (HY) were obtained in HRT of 8 h, R3 (C/N=200) and C/P=300 (1.758 mol H2.mol glucose-1) and they were related to fermentative pathways of ethanol, butyric and acetic acid production. The highest value of ethanol yield (EtOHY) (1.8 mol EtOH. mol glucose-1) was obtained in the 2nd Phase. By means of DGGE analyses was found highest similarity between C/P=700 and C/P=900 for R1 (87%), R2 (97%) and R3 (92%) in the 2nd Phase. Through phylogenetic affiliation of the 16S rRNA gene taken from samples of stages of highest H2 production it were obtained clones of hydrogen and ethanol producing specie related to Ethanoligenens sp., followed by the lactic acid bacteria Lactobacillus sp. and of the acetic and butyric acid producing Clostridium sp.. (AU)

• FAPESP's process: 11/02347-2 - INFLUENCE OF THE RATIO C/N AND C/R ON THE PRODUCTION OF HYDROGEN IN ANAEROBIC FLUDIZED BED REACTOR
• Grantee: Mariana Fronja Carosia
• Support Opportunities: Scholarships in Brazil - Doctorate