title: Calcium effect on fermentative hydrogen production in an anaerobic up-flow sludge blanket system.
abstract: The effects of calcium ions on a granular fermentative hydrogen production system were investigated in four lab-scale UASB reactors that fed on sucrose (20 g COD/L). The reactors were seeded with anaerobic sewage sludge microflora and operated at a temperature of 35 +/- 1 degrees, pH of 6.7 with hydraulic retention times (HRTs) of 24-6h. The experimental results indicated that calcium ion addition (75 - 150 mg/L) could enhance the granulation and elevate hydrogen production efficiency. However, an overly-high calcium concentration (300 mg-Ca(+2)/L) deteriorated the hydrogen productivity. A calcium concentration of 150 mg-Ca(+2)/L resulted in a peak HP of 3.6 mol H2/mol-sucrose and HPR of 807 mmol-H2/L-d at HRTs of 8 and 6 h, respectively. The EPS concentration of biohydrogenic biomass was higher than that of the aerobic or methanogenic biomass. The protein/carbon-ratio ranged from 0.17 to 0.26%. The multinomial regression analysis shows that the 75 - 150 mg-Ca(+2)/L calcium concentrations and HRT of 6 h were the optimal operating conditions to efficiently produce hydrogen.
authors.affiliation: BioHydrogen Laboratory, Department of Hydraulic Engineering, Feng Chia University, P.O. Box 25-123, Taichung 40724, Chinese, Taiwan.
authors.forename: F Y
authors.initials: FY
authors.lastname: Chang
authors.forename: C Y
authors.initials: CY
authors.lastname: Lin
mesh_terms: D000693:Anaerobiosis; D018533:Biomass; D019149:Bioreactors; D002118:Calcium / Q000494:pharmacology*; D002244:Carbon / Q000378:metabolism; D005285:Fermentation / Q000187:drug effects*; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D012044:Regression Analysis; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D011506:Proteins; D012722:Sewage; D013395:Sucrose; D002244:Carbon; D006859:Hydrogen; D008697:Methane; D002118:Calcium