Methanol conversion in high-rate anaerobic reactors

2001 ◽  
Vol 44 (8) ◽  
pp. 7-14 ◽  
Author(s):  
J. Weijma ◽  
A.J.M. Stams

An overview on methanol conversion in high-rate anaerobic reactors is presented, with the focus on technological as well as microbiological aspects. The simple C1-compound methanol can be degraded anaerobically in a complex way, in which methanogens, sulfate reducing bacteria and homoacetogens interact cooperatively or competitively at substrate level. This interaction has large technological implications as it determines the final product of methanol mineralization, methane or carbon dioxide. The degradation route of methanol may be entirely different when environmental conditions change. Direct methanogenesis from methanol seems the predominant mineralization route under mesophilic conditions both in the absence and the presence of sulfate. Under thermophilic conditions methanol oxidation to carbon dioxide and hydrogen appears to play an important role. The UASB technology for mesophilic digestion of methanolic waste has presently reached full-scale maturity. The potential of methanol as feedstock for anaerobic processes is discussed.

1993 ◽  
Vol 40 (4) ◽  
pp. 575-581 ◽  
Author(s):  
A. Visser ◽  
P. A. Alphenaar ◽  
Y. Gao ◽  
G. van Rossum ◽  
G. Lettinga

1987 ◽  
Vol 19 (12) ◽  
pp. 237-241 ◽  
Author(s):  
H. M. Pinheiro ◽  
M. T. Reis ◽  
J. M. Novais

Colour changes and other marked disturbances were observed at a high-rate photosynthetic pond system at Alcochete, Portugal. Previous chemical and microbiological tests made it possible to attribute these occurrences to the proliferation of purple sulfur bacteria, following the probable production of sulfide inside the ponds by sulfate-reducing bacteria. Results from more recent tests and observations are presented, which confirm the earlier conclusions, in addition to revealing a number of inadequacies in the ponds chosen operating conditions, which are in all probability at the origin of the observed disturbances. Corrective actions planned include a more efficient mixing of pond contents, the strict prevention of contamination with salty estuarine waters and the control of residence times and bottom sludge accumulation.


2010 ◽  
Vol 44 (14) ◽  
pp. 4261-4269 ◽  
Author(s):  
P. Ryan ◽  
C. Forbes ◽  
S. McHugh ◽  
C. O’Reilly ◽  
G.T.A. Fleming ◽  
...  

2021 ◽  
Vol 225 ◽  
pp. 05001
Author(s):  
Vladimir Vigdorovich ◽  
Liudmila Tsygankova ◽  
Natalia Shel ◽  
Nedal Alshikha

The universality of inhibitors is understood as their ability to inhibit several types of corrosion attack: hydrogen sulfide and carbon dioxide corrosion, hydrogen diffusion into metal, development of sulfate-reducing and other types of bacteria, negative impact on the mechanical properties of metals. Indicators of universalism of new inhibitor have been studied. Producer of the inhibiting compositions is Limited Liability Company «INCORGAZ» (S-Petersburg, Russia). The efficacy of the inhibitor in the concentration of 25 - 200 mg/L has been studied with respect to carbon steel in a highly mineralized chloride medium (pH= 6) and NACE medium (5 g/L NaCl, 0.25 g/L CH3COOH, pH =3.5) containing H2S (50-400 mg/L) and CO2 (1at) separately and together. The bactericidal properties of the inhibitor were studied with respect to sulfate-reducing bacteria in the Postgate medium. The investigations were carried out by the methods of linear polarization resistance, electrochemical impedance spectroscopy, gravimetry, potentiodynamic polarization. The protective effectiveness of the inhibitor reaches 80% in the presence of CO2 and 90% in hydrogen sulphide environments. The inhibitor repeatedly reduces the number of sulfate-reducing bacteria and the production of biogenic hydrogen sulfide and inhibits the diffusion of hydrogen into steel.


2000 ◽  
Vol 42 (5-6) ◽  
pp. 251-258 ◽  
Author(s):  
J. Weijma ◽  
J.-P. Haerkens ◽  
A.J.M. Stams ◽  
L.W. Hulshoff Pol ◽  
G. Lettinga

Thermophilic sulfite and sulfate reduction offers good prospects as part of an alternative technology to conventional off-gas desulfurization technologies. Thermophilic sulfate and sulfite reduction with methanol as the sole carbon and energy source for the sulfate reducing bacteria was studied in lab-scale Expanded Granular Sludge Bed (EGSB) reactors operated at 65 °C and pH 7.5. At a hydraulic retention time (HRT) of 4 hr, sulfite and sulfate elimination rates of up to 0.22 mol-S.l-1.day-1 (100% elimination) and 0.15 mol-S.l-1.day-1 (80% elimination), respectively, were achieved. Sulfite and sulfate reduction accounted for 85–90% of the electrons released during degradation of methanol. In addition, 10–13% and 1–2% of the consumed methanol was converted to acetate and methane, respectively. Acetate was not utilized as electron donor for sulfate reduction. Acetate production seemed to be linearly correlated to the amount of sulfite and sulfate reduced. Sulfite disproportionating activity of the sludge was demonstrated by the simultaneous appearance of sulfide and sulfate in batch tests with sulfite. However, sulfite disproportionation rates were 4 times lower than sulfate reduction rates with methanol. The results clearly demonstrate that methanol can be efficiently used as electron and carbon source to obtain high sulfite and sulfate elimination rates in thermophilic bioreactors.


2020 ◽  
Vol 82 (5) ◽  
pp. 11-20
Author(s):  
D.R. Abdulina ◽  
◽  
L.M. Purish ◽  
G.O. Iutynska ◽  
◽  
...  

The studies of the carbohydrate composition of the sulfate-reducing bacteria (SRB) biofilms formed on the steel surface, which are a factor of microbial corrosion, are significant. Since exopolymers synthesized by bacteria could activate corrosive processes. The aim of the study was to investigate the specificity of commercial lectins, labeled with colloidal gold to carbohydrates in the biofilm exopolymeric matrix produced by the corrosive-relevant SRB strains from man-caused ecotopes. Methods. Microbiological methods (obtaining of the SRB biofilms during cultivation in liquid Postgate B media under microaerophilic conditions), biochemical methods (lectin-binding analysis of 10 commercial lectins, labeled with colloidal gold), transmission electron microscopy using JEM-1400 JEOL. Results. It was shown using transmission electron microscopy that the binding of lectins with carbohydrates in the biofilm of the studied SRB strains occurred directly in the exopolymerіс matrix, as well as on the surfaces of bacterial cells, as seen by the presence of colloidal gold particles. For detection of the neutral carbohydrates (D-glucose and D-mannose) in the biofilm of almost all studied bacterial strains PSA lectin was the most specific. This lectin binding in biofilms of Desulfotomaculum sp. К1/3 and Desulfovibrio sp. 10 strains was higher in 90.8% and 94.4%, respectively, then for ConA lectin. The presence of fucose in the SRB biofilms was detected using LABA lectin, that showed specificity to the biofilm EPS of all the studied strains. LBA lectin was the most specific to N-аcetyl-D-galactosamine for determination of amino sugars in the biofilm. The amount of this lectin binding in D. vulgaris DSM644 biofilm was 30.3, 10.1 and 9.3 times higher than SBA, SNA and PNA lectins, respectively. STA, LVA and WGA lectins were used to detect the N-acetyl-Dglucosamine and sialic acid in the biofilm. WGA lectin showed specificity to N-acetyl-D-glucosamine in the biofilm of all the studied SRB; maximum number of bounded colloidal gold particles (175 particles/μm2) was found in the Desulfotomaculum sp. TC3 biofilm. STA lectin was interacted most actively with N-acetyl-D-glucosamine in Desulfotomaculum sp. TC3 and Desulfomicrobium sp. TC4 biofilms. The number of bounded colloidal gold particles was in 9.2 and 7.4 times higher, respectively, than using LVA lectin. The lowest binding of colloidal gold particles was observed for LVA lectin. Conclusions. It was identified the individual specificity of the 10 commercial lectins to the carbohydrates of biofilm matrix on the steel surface, produced by SRB. It was estimated that lectins with identical carbohydrates specificity had variation in binding to the biofilm carbohydrates of different SRB strains. Establishing of the lectin range selected for each culture lead to the reduction of the scope of studies and labor time in the researching of the peculiarities of exopolymeric matrix composition of biofilms formed by corrosiverelevant SRB.


2017 ◽  
Vol 28 (1-2) ◽  
pp. 84-95
Author(s):  
O. M. Moroz ◽  
S. O. Hnatush ◽  
Ch. I. Bohoslavets ◽  
T. M. Hrytsun’ ◽  
B. M. Borsukevych

Sulfate reducing bacteria, capable to reductive transformation of different nature pollutants, used in biotechnologies of purification of sewage, contaminated by carbon, sulfur, nitrogen and metal compounds. H2S formed by them sediment metals to form of insoluble sulfides. Number of metals can be used by these microorganisms as electron acceptors during anaerobic respiration. Because under the influence of metal compounds observed slowing of bacteria metabolism, selection isolated from technologically modified ecotops resistant to pollutions strains is important task to create a new biotechnologies of purification. That’s why the purpose of this work was to study the influence of potassium dichromate, present in medium, on reduction of sulfate and nitrate ions by sulfate reducing bacteria Desulfovibrio desulfuricans IMV K-6, Desulfovibrio sp. Yav-6 and Desulfovibrio sp. Yav-8, isolated from Yavorivske Lake, to estimate the efficiency of possible usage of these bacteria in technologies of complex purification of environment from dangerous pollutants. Bacteria were cultivated in modified Kravtsov-Sorokin medium without SO42- and FeCl2×4H2O for 10 days. To study the influence of K2Cr2O7 on usage by bacteria SO42- or NO3- cells were seeded to media with Na2SO4×10H2O or NaNO3 and K2Cr2O7 at concentrations of 1.74 mM for total content of electron acceptors in medium 3.47 mM (concentration of SO42- in medium of standard composition). Cells were also seeded to media with 3.47 mM Na2SO4×10H2O, NaNO3 or K2Cr2O7 to investigate their growth in media with SO42-, NO3- or Cr2O72- as sole electron acceptor (control). Biomass was determined by turbidymetric method, content of sulfate, nitrate, dichromate, chromium (III) ions, hydrogen sulfide or ammonia ions in cultural liquid – by spectrophotometric method. It was found that K2Cr2O7 inhibits growth (2.2 and 1.3 times) and level of reduction by bacteria sulfate or nitrate ions (4.2 and 3.0 times, respectively) at simultaneous addition into cultivation medium of 1.74 mM SO42- or NO3- and 1.74 mM Cr2O72-, compared with growth and level of reduction of sulfate or nitrate ions in medium only with SO42- or NO3- as sole electron acceptor. Revealed that during cultivation of bacteria in presence of equimolar amount of SO42- or NO3- and Cr2O72-, last used by bacteria faster, content of Cr3+ during whole period of bacteria cultivation exceeded content H2S or NH4+. K2Cr2O7 in medium has most negative influence on dissimilatory reduction by bacteria SO42- than NO3-, since level of nitrate ions reduction by cells in medium with NO3- and Cr2O72- was a half times higher than level of sulfate ions reduction by it in medium with SO42- and Cr2O72-. The ability of bacteria Desulfovibrio sp. to priority reduction of Cr2O72- and after their exhaustion − NO3- and SO42- in the processes of anaerobic respiration can be used in technologies of complex purification of environment from toxic compounds.


2016 ◽  
Vol 14 (3) ◽  
pp. 557-561
Author(s):  
Nguyễn Thị Yên ◽  
Kiều Thị Quỳnh Hoa

Lead contaminated wastewater negatively impacts to living organisms as well as humans. In recent years, a highly promising biological process using the anaerobic production of sulfide ions by sulfate-reducing bacteria has presented itself as an alternative option for the removal of lead. This process is based on microbial utilization of electron donors, such as organic compounds (carbon sources), and sulfate as the terminal electron acceptor for sulfide production. The biogenic hydrogen sulfide reacts with dissolved heavy metals to form insoluble metal sulfide precipitates Removal of lead by an enriched consortium of sulfate-reducing bacteria (DM10) was evaluated sulfate reduction, sulfide production and lead precipitation. Four parallel anaerobic continuous stirred tank reactors (CSTR, V = 2L) (referred as R1 - R4) were fed with synthetic wastewater containing Pb2+ in the concentrations of 0, 100, 150 and 200 mg L-1 of lead and operated with a hydraulic retention time of 5 days for 40 days. The loading rates of each metal in R1- R4 were 0, 20, 30 and 40 mg L-1 d-1, respectively. The results showed that there was no inhibition of SRB growth and that lead removal efficiencies of 99-100% for Pb2+ were achieved in R2 (100 mg L-1) and R3 (150 mg L-1) throughout the experiment. For the highest lead concentration of  200 mg L-1, a decrease in efficiency of removal (from 100 to 96%) was observed at the end of the experiment. The obtained result of this study might help for a better control operation and performance improvements of reactors.


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