Xuehua Zhou

Photo-fermentative hydrogen production in a 4 m3 baffled reactor: Effects of hydraulic retention time

A 4m3 pilot-scale baffled continuous-flow photoreactor with four sequential chambers (#1-#4) was established and tested to evaluate its photo-fermentative hydrogen production from wastewater that contains (10g/L glucose using a functional consortium at 30°C, under light with an intensity of 3000±200lux with a hydraulic retention time (HRT) of 24-72h. The hydrogen production rate and the broth characteristics varied significantly in the flow direction. The hydrogen production rate was highest in chamber #1, and lower in chambers #2-#4 at an HRT of 72h, while the peak production rate shifted to the latter chambers as the HRT was shortened. The overall H2 production rate increased as HRT decreased, but was not consistent with the predictions that were based on the complete-mixing assumption.

Effect of substrate concentration on hydrogen production by photo-fermentation in the pilot-scale baffled bioreactor.

Effect of substrate concentration on photo-fermentative hydrogen production was studied with a self-designed 4m3 pilot-scale baffled photo-fermentative hydrogen production reactor (BPHR). The relationships between parameters, such as hydrogen production rate (HPR, mol H2/m3/d), hydrogen concentration, pH value, oxidation-reduction potential, biomass concentration (volatile suspended solids, VSS) and reducing sugar concentration, during the photo-fermentative hydrogen production process were investigated. The highest HPR of 202.64±8.83mol/m3/d was achieved in chamber #3 at a substrate concentration of 20g/L. Hydrogen contents were in the range of 42.19±0.94%-49.71±0.27%. HPR increased when organic loading rate was increased from 3.3 to 20g/L/d, then decreased when organic loading rate was further increased to 25g/L/d. A maximum HPR of 148.65±4.19mol/m3/d was obtained when organic loading rate was maintained at 20g/L/d during continuous bio-hydrogen production.

Sequential dark and photo fermentation hydrogen production from hydrolyzed corn stover: A pilot test using 11 m 3 reactor

Pilot tests of sequential dark and photo fermentation H2 production were for the first time conducted in a 11 m3 reactor (3 m3 for dark and 8 m3 for photo compartments). A combined solar and light-emitting diode illumination system and a thermal controlling system was installed and tested. With dark fermentation unit maintained at pH 4.5 and 35 °C and photo fermentation unit at pH 7.0 and 30 °C, the overall biogas production rate using hydrolyzed corn stover as substrate reached 87.8 ± 3.8 m3/d with 68% H2 content, contributed by dark unit at 7.5 m3-H2/m3-d and by photo unit at 4.7 m3/m3-d. Large variation was noted for H2 production rate in different compartments of the tested units, revealing the adverse effects of poor mixing, washout, and other inhomogeneity associated with large reactor operations.

Comparison of sodium hydroxide and calcium hydroxide pretreatments of giant reed for enhanced enzymatic digestibility and methane production

NaOH pretreatment with leachate reuse and Ca(OH)2 pretreatment were compared for improved enzymatic digestibility and biogas production from giant reed, a promising energy crop. The NaOH pretreatment with leachate reuse increased glucose yields during enzymatic hydrolysis by 2.6-fold, and methane yields during anaerobic digestion by 1.4- to 1.6-fold. However, NaOH pretreatment had a negative net benefit (i.e., revenue from increased energy production minus chemical cost). Pretreatment with 7-20% Ca(OH)2 not only improved glucose yield and methane yield by up to 2.3-fold and 1.4-fold, respectively, but also obtained a net benefit of

Bio-hydrogen production from apple waste by photosynthetic bacteria HAU-M1

1.1-5.8/tonne dry biomass. Thus, Ca(OH)2 pretreatment was shown to be more feasible than NaOH pretreatment for biogas production from giant reed.