Activity, structure, and stratification of membrane-attached methanotrophic biofilms cometabolically degrading trichloroethylene

A membrane-attached methanotrophic biofilm reactor was developed for the cometabolic degradation of trichloroethylene (TCE). In this reactor, CH4 and O2 are supplied to the interior of the biofilm through the membrane, while TCE-contaminated water is supplied to the exterior, creating a “counter-diffusional” effect that minimizes competitive inhibition between TCE and CH4. In addition, this novel design provides 100% CH4 and O2 transfer efficiencies, promotes the development of a thick biofilm, and minimizes the negative effects of TCE byproduct toxicity. The reactor sustained 80-90% TCE removals at TCE loading rates ranging from 100-320 μmol/m2/d. Chloride mass balances demonstrated that 60-80% of the TCE removed was mineralized. The maximum TCE transformation yield was 1.8 mmol of TCE removed per mole of CH4 utilized, although higher transformation yields are expected at higher TCE loading rates. The CH4 utilization rate was 0.20 mol/m2/d. Scanning electron microscopy (SEM) revealed a dense biofilm with a thickness of at least 400 μm. SEM and transmission electron microscopy (TEM) analyses indicated that the “holdfast” material associated with rosette formation in planktonic Methylosinus trichosporium OB3b (M.t. OB3b) cells might also contribute to pure-culture biofilm development. In addition, fimbriae-like structures not commonly associated with methanotrophic bacteria were observed in pure-culture M.t. OB3b biofilms. Finally, fluorescent in situ hybridization (FISH) analyses showed the presence of discrete microcolonies of serine-pathway methanotrophs within mixed-culture biofilms.

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RESEARCH AND EVALUATE TREATMENT EFFICIENCY ON TAPIOCA PROCESSING INDUSTRIAL WASTEWATER BY AEROBIC BIOFILTER TECHNOLOGY WITH VARIOUS MATERIALS

Science and Technology Development Journal ◽

10.32508/stdj.v13i3.2143 ◽

2010 ◽

Vol 13 (3) ◽

pp. 54-66

Author(s):

Phuong Thi Thanh Nguyen ◽

Phuoc Van Nguyen ◽

Anh Cam Thieu

Keyword(s):

Wastewater Treatment ◽

Industrial Wastewater ◽

Utilization Rate ◽

Organic Loading ◽

Treatment Efficiency ◽

Research Results ◽

Loading Rates

This study was performed to evaluate the efficiency of tapioca processing wastewater treatment using aerobic biofilter with variety of biofilter media: coir, coal, PVC plastic and Bio - Ball BB15 plastic. Research results in the lab demonstrated all four aerobic biofilter models processed can treated completely N and COD which COD reached 90-98% and N reached 61-92%, respectively, at the organic loading rates in range of 0.5, 1, 1.5 and 2 kgCOD/m3.day. The results identified coir filter was the best in four researched materials with removal COD and specific substract utilization rate can reach 98%, and 0.6 kg COD/kgVSS.day. Research results open the new prospects for the application of the cheap materials, available for wastewater treatment.

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Anaerobic Thermophilic (55°C) Treatment of TMP Whitewater in Reactors Based on Biomass Attachment and Entrapment

Water Science & Technology ◽

10.2166/wst.1999.0696 ◽

1999 ◽

Vol 40 (11-12) ◽

pp. 67-75 ◽

Cited By ~ 5

Author(s):

Sigrun J. Jahren ◽

Jukka A. Rintala ◽

Hallvard Ødegaard

Keyword(s):

Granular Sludge ◽

Biofilm Reactor ◽

Upflow Anaerobic Sludge Blanket ◽

Hybrid Reactor ◽

Anaerobic Sludge ◽

Loading Rates ◽

Anaerobic Reactors ◽

Multi Stage ◽

Degradation Rates ◽

Thermomechanical Pulping

Thermomechanical pulping (TMP) whitewater was treated in thermophilic (55°C) anaerobic laboratory-scale reactors using three different reactor configurations. In all reactors up to 70% COD removals were achieved. The anaerobic hybrid reactor, composed of an upflow anaerobic sludge blanket (UASB) and a filter, gave degradation rates up to 10 kg COD/m3d at loading rates of 15 kg COD/m3d and hydraulic retention time (HRT) of 3.1 hours. The anaerobic multi-stage reactor, consisting of three compartments, each packed with granular sludge and carrier elements, gave degradation rates up to 9 kg COD/m3d at loading rates of 15-16 kg COD/m3d, and HRT down to 2.6 hours. Clogging and short circuiting eventually became a problem in the multi-stage reactor, probably caused by too high packing of the carriers. The anaerobic moving bed biofilm reactor performed similar to the other reactors at loading rates below 1.4 kg COD/m3d, which was the highest loading rate applied. The use of carriers in the anaerobic reactors allowed short HRT with good treatment efficiencies for TMP whitewater.

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Use of a dynamic gassing-out method for activity and oxygen diffusion coefficient estimation in biofilms

Water Science & Technology ◽

10.2166/wst.1998.0611 ◽

1998 ◽

Vol 37 (4-5) ◽

pp. 171-175

Author(s):

Artem Khlebnikov ◽

Falilou Samb ◽

Paul Péringer

Keyword(s):

Diffusion Coefficient ◽

Oxygen Uptake ◽

Oxygen Diffusion ◽

Fixed Bed ◽

Biofilm Reactor ◽

Strictly Aerobic ◽

Comamonas Testosteroni ◽

Respiration Activity ◽

Oxygen Diffusion Coefficient ◽

Biofilm Development

p-toluenesulphonic acid degradation by Comamonas testosteroni T-2 in multi-species biofilms was studied in a fixed bed biofilm reactor. The polypropylene static mixer elements (Sulzer Chemtech Ltd., Switzerland) were used as a support matrix for biofilm formation. Biofilm respiration was estimated using the dynamic gassing-out oxygen uptake method. A strong relation between oxygen uptake and reactor degradation efficiency was observed, because p-toluenesulphonate degradation is a strictly aerobic process. This technique also allowed us to estimate the thickness of the active layer in the studied system. The mean active thickness was in order of 200 μm, which is close to maximum oxygen penetration depth in biofilms. A transient mathematical model was established to evaluate oxygen diffusitivity in non-steady-state biofilms. Based on the DO concentration profiles, the oxygen diffusion coefficient and the maximum respiration activity were calculated. The oxygen diffusion coefficient obtained (2 10−10-1.2 10−9 m2 s−1) is in good agreement with published values. The DO diffusion coefficient varied with biofilm development. This may be, most likely, due to the biofilm density changes during the experiments. The knowledge of diffusivity changes in biofilms is particularly important for removal capacity estimation and appropriate reactor design.

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Inhibition kinetics for propionate degradation using propionate-enriched mixed cultures

Water Science & Technology ◽

10.2166/wst.1998.0836 ◽

1998 ◽

Vol 38 (8-9) ◽

pp. 443-451 ◽

Cited By ~ 5

Author(s):

S. H. Hyun ◽

J. C. Young ◽

I. S. Kim

Keyword(s):

Phase I ◽

Competitive Inhibition ◽

Gas Production ◽

Phase Iii ◽

Utilization Rate ◽

Inhibition Kinetics ◽

Wide Range ◽

Propionate Degradation ◽

Acetate Utilization ◽

Velocity Coefficient

To study propionate inhibition kinetics, seed cultures for the experiment were obtained from a propionate-enriched steady-state anaerobic Master Culture Reactor (MCR) operated under a semi-continuous mode for over six months. The MCR received a loading of 1.0 g propionate COD/l-day and was maintained at a temperature of 35±1°C. Tests using serum bottle reactors consisted of four phases. Phase I tests were conducted for measurement of anaerobic gas production as a screening step for a wide range of propionate concentrations. Phase II was a repeat of phase I but with more frequent sampling and detailed analysis of components in the liquid sample using gas chromatography. In phase III, different concentrations of acetate were added along with 1.0 g propionate COD/l to observe acetate inhibition of propionate degradation. Finally in phase IV, different concentrations of propionate were added along with 100 and 200 mg acetate/l to confirm the effect of mutual inhibition. Biokinetic and inhibition coefficients were obtained using models of Monod, Haldane, and Han and Levenspiel through the use of non-linear curve fitting technique. Results showed that the values of kp, maximum propionate utilization rate, and Ksp, half-velocity coefficient for propionate conversion, were 0.257 mg HPr/mg VSS-hr and 200 mg HPr/l, respectively. The values of kA, maximum acetate utilization rate, and KsA, half-velocity coefficient for acetate conversion, were 0.216 mg HAc/mg VSS-hr and 58 mg HAc/l, respectively. The results of phase III and IV tests indicated there was non-competitive inhibition when the acetate concentration in the reactor exceeded 200 mg/l.

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Study on the path of Integration use of Land Resource elements under the background of Rural Revitalization

E3S Web of Conferences ◽

10.1051/e3sconf/202123601040 ◽

2021 ◽

Vol 236 ◽

pp. 01040

Author(s):

Hong Tang ◽

Changpin Ji ◽

Yan Zhao

Keyword(s):

Rural Areas ◽

Rapid Development ◽

Economic Benefits ◽

Utilization Rate ◽

Circulation System ◽

Land Resource ◽

Resource Integration ◽

Land Utilization ◽

Negative Effects ◽

Rural Economic Development

At present, with the rapid development of urban-rural integration, the problems of land fragmentation in rural areas, such as low land use rate, poor economic benefits, many production conflicts and disputes, land distribution difficulties and other negative effects, continue to appear, and the rural economic development is very severe. Based on this, this paper mainly studies the path of land resource integration, studies the reform of land system in various aspects, such as land circulation system, homestead reform, land acquisition system and other specific systems, and studies the specific path of land resource integration, so as to promote the land utilization rate, promote the rapid development of population industry and its development The increase of farmers' income.

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Toxicity of anionic and cationic surfactant to Acinetobacter junii in pure culture

Open Life Sciences ◽

10.2478/s11535-007-0029-7 ◽

2007 ◽

Vol 2 (3) ◽

pp. 405-414 ◽

Cited By ~ 22

Author(s):

Jasna Hrenovic ◽

Tomislav Ivankovic

Keyword(s):

Activated Sludge ◽

Pure Culture ◽

Sodium Dodecyl ◽

P Uptake ◽

Hexadecyltrimethylammonium Bromide ◽

Negative Effects ◽

Acinetobacter Junii ◽

Uptake Rates ◽

Eukaryotic Organisms ◽

P Uptake Rates

AbstractThe harmful effects of surfactants to the environment are well known. We were interested in investigating their potential toxicity in a pure culture of Acinetobacter junii, a phosphate (P)-accumulating bacterium. Results showed a high acute toxicity of sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (HDTMA) against A. junii. The estimated EC50 values of the HDTMA for the inhibition of CFUs in the pure culture of A. junii was 3.27 ± 1.12 × 10−7 mol L−1 and for the inhibition of the P-uptake rates 2.47 ± 0.51 × 10−6 mol L−1. For SDS, estimated EC50 values for the inhibition of CFUs in the pure culture of A. junii was 5.00 ± 2.95 × 10−6 mol L−1 and for the inhibition of the P-uptake rates 3.33 ± 0.96 × 10−4 mol L−1. The obtained EC50 values in the standardised yeast toxicity test using Saccharomyces cerevisiae were 3.03 ± 0.38 × 10−4 and 4.33 ± 0.32 × 10−5 mol L−1 for SDS and HDTMA, respectively. These results emphasized the need to control concentrations of surfactants entering the activated sludge system. The negative effects of these toxicants could greatly decrease populations of P-accumulating bacteria, as well as eukaryotic organisms, inhabiting activated sludge systems, which in turn could result in the decrease of the system efficiency.

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Biofilm development in down flow anaerobic fluidised bed reactors under transient conditions

Water Science & Technology ◽

10.2166/wst.2002.0485 ◽

2002 ◽

Vol 46 (1-2) ◽

pp. 253-256

Author(s):

F. Tessele ◽

G. Englert ◽

L.O. Monteggia

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Fluidised Bed ◽

Initial Adhesion ◽

Scale Down ◽

Synthetic Solution ◽

Biofilm Development ◽

Fluidised Bed Reactor ◽

Biofilm Structure ◽

Scanning Electron

Biofilm development onto polypropylene particles (<4 mm) was studied in a laboratory-scale down flow anaerobic fluidised bed reactor. The reactor was fed with a synthetic solution containing sucrose and nutrients, and operated at 35°C during 65 days at 44% bed expansion rate and 36 h HRT. Scanning electron microscopy (SEM) monitored the biofilm development. Initial adhesion occurred within the first 6 hours and after day 44 biofilm structure was complete. The presence of attached cells morphologically similar to Methanotrix bacilli and Methanosarcina sp. was observed by Scanning Electron Microscopy (SEM). The biofilm and the carrier surface roughness were measured by atomic force microscopy (AFM) and yielded 9.1 and 75 nm respectively. Results also showed good correlation between the SEM characterisation and the conventional anaerobic reactor parameters.

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Colonization of Barley Grain by Penicillium verrucosum and Ochratoxin A Formation in the Presence of Competing Fungi

Journal of Food Protection ◽

10.4315/0362-028x-59.12.1311 ◽

1996 ◽

Vol 59 (12) ◽

pp. 1311-1317 ◽

Cited By ~ 25

Author(s):

NANNAPANENI RAMAKRISHNA ◽

JOHN LACEY ◽

JOHN E. SMITH

Keyword(s):

Electron Microscopy ◽

Ochratoxin A ◽

Pure Culture ◽

Barley Grain ◽

Enzyme Linked Immunosorbent Assay ◽

Seed Infection ◽

Fusarium Sporotrichioides ◽

Penicillium Verrucosum ◽

Grain Surface ◽

Scanning Electron

Colonization of barley grain by Penicillium verrucosum and the formation of ochratoxin A were studied, both in pure culture and when paired with Aspergillus flavus, Fusarium sporotrichioides, and Hyphopichia burtonii, at 20° and 30°C and at 0.97, 0.95 and 0.90 aw over a 3-week period. Grain colonization was assessed on the basis of visible molding, seed infection, and numbers of CFU and by observing hyphal extension on the grain surface by scanning electron microscopy. Ochratoxin A concentrations were assayed by enzyme-linked immunosorbent assay using a monoclonal antibody. Germination of P. verrucosum spores was unaffected by the presence of other species. However, seed infection under most conditions was markedly decreased, relative to pure culture, by the presence of A. flavus and H. burtonii, but only slightly by F. sporotrichioides. The number of CFU of P. verrucosum was only slightly decreased in the presence of other species under most conditions. Generally, production of ochratoxin A by P. verrucosum was inhibited, sometimes significantly, in the presence of A. flavus and H. burtonii, but was changed only slightly by the presence of F. sporotrichioides. There was occasionally temporary enhancement in ochratoxin A production with all species during the 3-week incubation period.

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