Feasibility studies on continuous hydrogen production using photo-fermentative sequencing batch reactor

Xie, Guo-Jun; Liu, Bingfeng; Guo, Wei; Ding, Jie; Xing, Defeng; Nan, Jun; Ren, Hongyan; Ren, Nan-Qi

doi:10.1016/j.ijhydene.2012.02.107

Cited by 30 publications

(12 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The COD conversion coefficients are 1.5 g COD/g protein and 1.06 g COD/g carbohydrate . The measurement of SCFA was the same as described in the literature (Yuan et al, 2006), and the composition in biogas was analyzed by gas chromatograph equipped with a thermal conductivity detector according to the method documented in the literature (Xie et al, 2012;Wang et al, 2015). L-alanine was determined according to the method documented in the literature (Bergmeyer and Horder, 1980).…”

Section: 8mentioning

confidence: 99%

Free nitrous acid serving as a pretreatment method for alkaline fermentation to enhance short-chain fatty acid production from waste activated sludge

et al. 2015

View full text Add to dashboard Cite

Alkaline condition (especially pH 10) has been demonstrated to be a promising method for short-chain fatty acid (SCFA) production from waste activated sludge anaerobic fermentation, because it can effectively inhibit the activities of methanogens. However, due to the limit of sludge solubilization rate, long fermentation time is required but SCFA yield is still limited. This paper reports a new pretreatment method for alkaline fermentation, i.e., using free nitrous acid (FNA) to pretreat sludge for 2 d, by which the fermentation time is remarkably shortened and meanwhile the SCFA production is significantly enhanced. Experimental results showed the highest SCFA production of 370.1 mg COD/g VSS (volatile suspended solids) was achieved at 1.54 mg FNA/L pretreatment integration with 2 d of pH 10 fermentation, which was 4.7- and 1.5-fold of that in the blank (uncontrolled) and sole pH 10 systems, respectively. The total time of this integration system was only 4 d, whereas the corresponding time was 15 d in the blank and 8 d in the sole pH 10 systems. The mechanism study showed that compared with pH 10, FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. After FNA pretreatment, pH 10 treatment (1 d) caused 38.0% higher substrate solubilization than the sole FNA, which indicated that FNA integration with pH 10 could cause positive synergy on sludge solubilization. It was also observed that this integration method benefited hydrolysis and acidification processes. Therefore, more SCFA was produced, but less fermentation time was required in the integrated system.

show abstract

Section: 8mentioning

confidence: 99%

Free nitrous acid serving as a pretreatment method for alkaline fermentation to enhance short-chain fatty acid production from waste activated sludge

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Recently, biological hydrogen production processes, especially photo-fermentative hydrogen production by PFB has been attracting more and more attention, as it utilizes various renewable sources like biomass and sunlight to produce an ideal, renewable and carbon-free energy for the future [3]. However, it should be realized that most of photo-fermentative processes are based on suspended culture [4-6] in which it is difficult to achieve high biomass concentration, effective retention and separation of PFB biomass, resulting from poor flocculation of PFB [7]. For steady-state operation of photobioreactor, due to the poor flocculability, PFB cells cannot be efficiently separated from supernatant and rush out with effluent from reactor continuously.…”

Section: Introductionmentioning

confidence: 99%

Photo-fermentative bacteria aggregation triggered by L-cysteine during hydrogen production

Xie

Liu

Xing

et al. 2013

Biotechnol Biofuels

Self Cite

View full text Add to dashboard Cite

BackgroundHydrogen recovered from organic wastes and solar energy by photo-fermentative bacteria (PFB) has been suggested as a promising bioenergy strategy. However, the use of PFB for hydrogen production generally suffers from a serious biomass washout from photobioreactor, due to poor flocculation of PFB. In the continuous operation, PFB cells cannot be efficiently separated from supernatant and rush out with effluent from reactor continuously, which increased the effluent turbidity, meanwhile led to increases in pollutants. Moreover, to replenish the biomass washout, substrate was continuously utilized for cell growth rather than hydrogen production. Consequently, the poor flocculability not only deteriorated the effluent quality, but also decreased the potential yield of hydrogen from substrate. Therefore, enhancing the flocculability of PFB is urgent necessary to further develop photo-fermentative process.ResultsHere, we demonstrated that L-cysteine could improve hydrogen production of Rhodopseudomonas faecalis RLD-53, and more importantly, simultaneously trigger remarkable aggregation of PFB. Experiments showed that L-cysteine greatly promoted the production of extracellular polymeric substances, especially secretion of protein containing more disulfide bonds, and help for enhancement stability of floc of PFB. Through formation of disulfide bonds, L-cysteine not only promoted production of EPS, in particular the secretion of protein, but also stabilized the final confirmation of protein in EPS. In addition, the cell surface elements and functional groups, especially surface charged groups, have also been changed by L-cysteine. Consequently, absolute zeta potential reached a minimum value at 1.0 g/l of L-cysteine, which obviously decreased electrostatic repulsion interaction energy based on DLVO theory. Total interaction energy barrier decreased from 389.77 KT at 0.0 g/l of L-cysteine to 127.21 kT at 1.0 g/l.ConclusionsThus, the strain RLD-53 overcame the total energy barrier and flocculated effectively. After a short settlement, the biomass rush out will be significantly reduced and the effluent quality will be greatly improved in the continuous operation. Furthermore, aggregation of PFB could enable high biomass hold-up of photobioreactor, which allows the photobioreactor to operate at low hydraulic retention time and high organic loading rate. Therefore, the described flocculation behaviour during photo-hydrogen production is potentially suitable for practicable application.

show abstract

“…And aerobic fluidized bed photo‐reactor compatible with the fluidization characteristics was designed for continuous hydrogen yielding (Ren et al ., ), which showed fairly stable and efficient hydrogen production. Moreover, sequencing batch (Xie et al ., ) and fed‐batch (Ren et al ., ) culture have been suggested as optimum operation modes due to high biomass retaining capacity, but have not been used widely in hydrogen production by photofermentation (Argun & Kargi, ). Therefore, enhancing the flocculation of PFB and using high biomass retaining operation modes are the promising strategies for maximum conversion of the feedstock into hydrogen.…”

Section: Resultsmentioning

confidence: 99%

Material flow analysis of feedstock for enhancing its conversion efficiency during continuous photo‐hydrogen production

et al. 2013

Self Cite

View full text Add to dashboard Cite

The practical application of photofermentative hydrogen production process has been generally limited by the low feedstock conversion efficiency. In this work, material flow analysis (MFA) was applied into continuous photohydrogen to investigate the material flow of feedstock. Maximum feedstock utilization for hydrogen production (31.87%) was obtained at an hydraulic retention time of 60 h and influent acetate concentration of 40 mmol l À1 , corresponding to maximum hydrogen yield of 1.89 mol H 2 mol À1 acetate. MFA showed that due to the poor flocculation, photofermentative bacteria (PFB) cannot be efficiently separated from supernatant and rushed out with effluent continuously. To replenish the biomass washout, most of feedstock was continuously utilized for cell growth rather than hydrogen production, which caused low feedstock conversion efficiency. The results showed that poor flocculation of PFB resulting in low biomass retention capacity of photobioreactor was the origin of low feedstock conversion efficiency. Therefore, enhancing flocculation of PFB and using high biomass retaining operation modes are essential to further develop photofermentative hydrogen production process.

show abstract

Feasibility studies on continuous hydrogen production using photo-fermentative sequencing batch reactor

Cited by 30 publications

References 35 publications

Free nitrous acid serving as a pretreatment method for alkaline fermentation to enhance short-chain fatty acid production from waste activated sludge

Free nitrous acid serving as a pretreatment method for alkaline fermentation to enhance short-chain fatty acid production from waste activated sludge

Photo-fermentative bacteria aggregation triggered by L-cysteine during hydrogen production

Material flow analysis of feedstock for enhancing its conversion efficiency during continuous photo‐hydrogen production

Contact Info

Product

Resources

About