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Shokri S, Bonakdarpour B, Abdollahzadeh Sharghi E. How high salt shock affects performance and membrane fouling characteristics of a halophilic membrane bioreactor used for treating hypersaline wastewater. CHEMOSPHERE 2024; 354:141716. [PMID: 38490610 DOI: 10.1016/j.chemosphere.2024.141716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 03/04/2024] [Accepted: 03/12/2024] [Indexed: 03/17/2024]
Abstract
In the present study, the effect of short-term salt shocks (13% and 20%) on the performance of a halophilic MBR bioreactor used to treat a hypersaline (5% salt) synthetic wastewater was considered. 13% and 20% salt shocks resulted in a transient and permanent decrease in chemical oxygen demand removal efficiency, respectively which could be correlated with soluble microbial products (SMP) concentration and specific oxygen uptake rate values of the halophilic population. DNA leakage tests suggested that both 13% and 20% short-term salt shocks resulted in some cell structural damage. During both 13% and 20% salt shocks mixed liquor SMP, extracellular polymeric substances (EPS), zeta potential and endogenous respiration increased while relative hydrophobicity, EPSp/EPSc and exogenous respiration decreased; in both cases, however, the pre-shock values for these parameters were restored after the removal of the salt shock. 13% salt shock resulted in a transient increase in the membrane fouling rate and a permanent rise in total membrane resistance (Rt). On the other hand, both membrane fouling rate and Rt increased during 20% salt shock. Membrane fouling rate initially reduced after the 20% salt shock removal but after 5 days a "TMP jump" occurred. The latter was caused by the higher steady state SMPc and SMPp concentrations after removal of 20% salt shock compared to pre-shock values. This might have either resulted in a decrease in critical flux or an increase in local flux above critical flux in some parts of the membrane. The contribution of cake layer resistance to overall membrane resistance increased after the 13% and 20% salt shocks. The findings of the present study reveal the robustness of halophilic MBRs against salt shocks in the treatment of hypersaline wastewater. However, in cases of very high salt shocks, appropriate membrane fouling reduction strategies should be carried out during its operation.
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Affiliation(s)
- Sousan Shokri
- Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Babak Bonakdarpour
- Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran.
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2
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Vanzetto GV, Thomé A. Toxicity of nZVI in the growth of bacteria present in contaminated soil. CHEMOSPHERE 2022; 303:135002. [PMID: 35597456 DOI: 10.1016/j.chemosphere.2022.135002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
The use of nano zero-valent iron (nZVI) for the remediation of degraded areas is a consolidated practice. However, the long-term reactions that occur in the environment remain unknown. This study aimed to evaluate the potential toxic effects on the growth of colony-forming units (CFUs) of Bacillus cereus and Pseudomona aeruginosa present in soil contaminated with hexavalent chromium (Cr6+) and pentachlorophenol (PCP) nanoremediated with nZVI. The treatments were natural soil (control), soil contaminated by Cr6+, soil contaminated by PCP, and soil contaminated by Cr6+ and PCP (Cr6+ and PCP), all in duplicate. The concentration of contaminants used was 100 mg/kg of soil. One of the drums of the duplicate received an injection of nZVI solution with a concentration of 50 g/kg. Analysis was performed 7, 15, 21, 30, 60, and 90 days after the nZVI injection. Temporary oscillations in the abundance of the microbiological community were observed, characterizing the adaptation of bacteria to the contaminants. The bacteria showed similar behavior. Ninety days after the injection of nZVI, the averages of the CFUs were statistically equal, with the lowest coefficient of variation and the highest concentration of CFUs occurring. The strains of B. cereus and P. aeruginosa were resistant to the concentrations of nZVI, Cr6+, and PCP. The nanoremediation of nZVI in soil contaminated by Cr6+ and PCP had no toxic effects on the population of the bacteria evaluated and did not present major disturbances in temperature, electrical conductivity, pH, and humidity over time.
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Affiliation(s)
| | - Antonio Thomé
- Professor Graduate Program in Engineering, University of Passo Fundo, Brazil
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3
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Tributyltin in Wastewater: Influence on the Performance of Suspended Growth Biological Processes. WATER 2022. [DOI: 10.3390/w14091483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The aim of this study was to evaluate the potential effect of tributyltin (TBT) on the performance of suspended-growth biological processes. The influence of TBT was evaluated for (i) the endogenous and exogenous respirations of heterotrophic micro-organisms in laboratory-scale batch reactors, taken from a municipal wastewater treatment plant and (ii) chemical oxygen demand (COD) removal, sludge production and oxygen consumption of a pilot-sale membrane bioreactor (MBR) system inoculated with heterotrophic micro-organisms taken from a MBR system. The batch experiments showed that the presence of TBT was likely to modify the activity of bacterial populations in endogenous conditions. The increase in endogenous oxygen needs suggested an increase in the maintenance requirements, essentially to manage the chemical stress induced by the presence of TBT. If the addition of TBT did not perturb COD removal in an MBR system, it limited sludge production and increased oxygen requirements; it is assumed that these modifications were linked with the necessity for the biomass to adapt in this stressful environment, as reflected by an increase in the maintenance requirements. These results emphasised that the respiratory activity of the bacterial cultures was modified by the presence of TBT, in the sense that an excess of oxygen was required to adapt to this chemical stress.
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Cházaro-Ruiz LF, López-Cázares MI, González I, Toriz Y, Alatriste-Mondragon F, Santana M, Celis LB. Improving Substrate Consumption and Decrease of Growth Yield in Aerobic Cultures of Pseudomonas denitrificans By Applying Low Voltages in Bioelectric Systems. Appl Biochem Biotechnol 2019; 190:1333-1348. [PMID: 31758363 DOI: 10.1007/s12010-019-03168-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 10/23/2019] [Indexed: 12/22/2022]
Abstract
It is well known that activated sludge treatment systems generate a lot of surplus sludge having environmental and economic impacts. Although several approaches have been proposed for the treatment/reuse of the excess of sludge, there are few studies focused on decreasing the biomass yield without affecting the metabolic activity. This work reports the effect of low magnitude electrical fields (0.07 to 0.2 V/cm) on the growth yield of a pure strain of Pseudomonas denitrificans (used as model microorganism). Cell potentials between 0.2 and 0.57 V were measured during 24 h to the aerobic culture; biomass production and substrate consumption were evaluated at regular intervals. Results indicated that the substrate (lactate) consumption efficiency increased with the applied potential, up to 100%, while the yield diminished 31% (0.34 g biomass/g lactate consumed) at 0.7 V vs. NHE. Bioenergetics showed that the fraction of electron equivalents toward biomass synthesis decreased from 0.68 (when no potential was applied) to 0.47 at 0.57 V, pointing out the redirection of the energy flow toward maintenance to cope with the stress caused by the imposed voltage. Therefore, the electrical stimulus could be used as control of biomass growth in aerobic wastewater treatment lines.
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Affiliation(s)
- Luis F Cházaro-Ruiz
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí, S.L.P, C.P.78216, México, Mexico.
| | - María Irene López-Cázares
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí, S.L.P, C.P.78216, México, Mexico
| | - Ignacio González
- Departamento de Química, Universidad Autónoma Metropolitana - Iztapalapa, Apdo. Postal 55-534, 09340, México City, 09340, Mexico
| | - Yanet Toriz
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí, S.L.P, C.P.78216, México, Mexico
| | - Felipe Alatriste-Mondragon
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí, S.L.P, C.P.78216, México, Mexico
| | - Marcela Santana
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí, S.L.P, C.P.78216, México, Mexico
| | - Lourdes B Celis
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí, S.L.P, C.P.78216, México, Mexico.
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Plater MJ, Harrison WTA. The complexation of 2,4-dinitrophenol with basic drugs: Acid + base = salt. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.1177/1747519819861079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Different drugs containing a basic nitrogen atom were crystallised with 2,4-dinitrophenol to study the mode of complexation in search of an antidote to 2,4-dinitrophenol poisoning. The protonated forms of quininium, quinidinium and trazodonium form N–H···O hydrogen bonds to the deprotonated O atom of the 2,4-dinitrophenolate anion, whereas haloperidolium forms a bifurcated N–H···(O,O) hydrogen bond to the deprotonated O atom of 2,4-dinitrophenol and an O atom of the adjacent nitro group. Hydrogen-bonded chains occur in the quininium, quinidinium and haloperidolium crystal structures, whereas the trazodonium structure consists of ion pairs. These results are discussed with a view to lowering the toxicity of 2,4-dinitrophenol in the body in the case of an overdose.
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Affiliation(s)
- M John Plater
- Department of Chemistry, University of Aberdeen, Aberdeen, UK
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Pokój T, Klimiuk E, Ciesielski S. Interactive effect of crude glycerin concentration and C:N ratio on polyhydroxyalkanoates accumulation by mixed microbial cultures modelled with Response Surface Methodology. WATER RESEARCH 2019; 156:434-444. [PMID: 30947043 DOI: 10.1016/j.watres.2019.03.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/04/2019] [Accepted: 03/18/2019] [Indexed: 05/26/2023]
Abstract
Response Surface Methodology (RSM) was used to investigate how the crude glycerin concentration and the carbon to nitrogen (C:N) ratio in the culture medium affect four indicators of polyhydroxyalkanoates (PHAs) accumulation by mixed microbial cultures (MMC): the observed coefficient of active-biomass yield (Yobs,BA), the observed coefficient of PHA yield (Yobs,PHA), the PHA content in biomass (XPHA) and the volumetric productivity (PrV). The C:N ratio had the largest effect on Yobs,BA and Yobs,PHA. When the C:N ratio was increased, Yobs,BA decreased and Yobs,PHA increased, regardless of the concentration of crude glycerin in the culture medium. The C:N ratio also had the largest effect on the PHA content, whereas volumetric productivity was strongly affected by both the C:N ratio and the crude glycerin concentration. The optimal conditions for PHA accumulation were a crude glycerin concentration of 8954 mg COD/L with a C:N ratio of 15.9 mg C/mg N-NH4, which gave a Yobs,BA of 0.29 mg CODBA/mg COD, a Yobs,PHA of 0.28 mg CODPHA/mg COD, a XPHA of 55.6% VSS and a PrV of 757.3 mg CODPHA/L⋅d (550.0 mg PHA/L⋅d). The accumulated PHAs consisted mainly of 3-hydroxybutyrate. By using RSM, it was possible to predict crude glycerin concentrations and C:N ratios not tested here that will allow desirable values of PHA content in biomass or PHA productivity, which can be useful for designing PHA production with MMC.
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Affiliation(s)
- Tomasz Pokój
- Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna Str. 45G, 10-719, Olsztyn, Poland.
| | - Ewa Klimiuk
- Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna Str. 45G, 10-719, Olsztyn, Poland
| | - Sławomir Ciesielski
- Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna Str. 45G, 10-719, Olsztyn, Poland
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Li C, Yang Y, Liu Y, Hou LA. Removal of PhACs and their impacts on membrane fouling in NF/RO membrane filtration of various matrices. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2017.11.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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8
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Bahar T, Golfier F, Oltéan C, Benioug M. An Upscaled Model for Bio-Enhanced NAPL Dissolution in Porous Media. Transp Porous Media 2016. [DOI: 10.1007/s11242-016-0718-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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The Effect of Heavy Metal-Induced Oxidative Stress on the Enzymes in White Rot Fungus Phanerochaete chrysosporium. Appl Biochem Biotechnol 2014; 175:1281-93. [DOI: 10.1007/s12010-014-1298-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 10/14/2014] [Indexed: 12/08/2022]
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10
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Zhang H, Gao Z, Zhang L, Song L. Performance enhancement and fouling mitigation by organic flocculant addition in membrane bioreactor at high salt shock. BIORESOURCE TECHNOLOGY 2014; 164:34-40. [PMID: 24835916 DOI: 10.1016/j.biortech.2014.04.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 06/03/2023]
Abstract
The main objective of this study was to investigate the effect of an organic flocculant (MPE50) addition on reducing membrane fouling and enhancing performance in membrane bioreactor (MBR) at the high salt shock. Results show that MPE50 addition is a reliable and effective approach in terms of both membrane fouling mitigation and pollutants removal improvement in the case of high salt shock. Compared to the control reactor, the MBR with MPE50 addition enhanced the average removal of COD, NH4(+)-N and TP by 4.1%, 13.2% and 21.2%, respectively. Due to the effect of flocculation and adsorption by MPE50, a significant reduction in the soluble microbial products (SMP) proteins amount was observed. As a result, the membrane fouling rate was mitigated successfully. Further, the increasing of mean particles size, Zeta potential and related hydrophobicity of the flocs would also have positive impacts on membrane fouling mitigation.
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Affiliation(s)
- Haifeng Zhang
- School of Chemistry Engineering, Northeast Dianli University, Jilin 132012, Jilin, PR China; Department of Civil and Environmental Engineering, Texas Tech University, 10th and Akron, Lubbock, TX 79409-1023, USA
| | - Zhongyu Gao
- School of Chemistry Engineering, Northeast Dianli University, Jilin 132012, Jilin, PR China
| | - Lanhe Zhang
- School of Chemistry Engineering, Northeast Dianli University, Jilin 132012, Jilin, PR China
| | - Lianfa Song
- Department of Civil and Environmental Engineering, Texas Tech University, 10th and Akron, Lubbock, TX 79409-1023, USA.
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11
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Anaerobic microbial growth near thermodynamic equilibrium as a function of ATP/ADP cycle: The effect of maintenance energy requirements. Biochem Eng J 2013. [DOI: 10.1016/j.bej.2013.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Guo WQ, Yang SS, Xiang WS, Wang XJ, Ren NQ. Minimization of excess sludge production by in-situ activated sludge treatment processes — A comprehensive review. Biotechnol Adv 2013; 31:1386-96. [DOI: 10.1016/j.biotechadv.2013.06.003] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/31/2013] [Accepted: 06/10/2013] [Indexed: 11/24/2022]
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Adaptation of the hydrocarbonoclastic bacterium Alcanivorax borkumensis SK2 to alkanes and toxic organic compounds: a physiological and transcriptomic approach. Appl Environ Microbiol 2013; 79:4282-93. [PMID: 23645199 DOI: 10.1128/aem.00694-13] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The marine hydrocarbonoclastic bacterium Alcanivorax borkumensis is able to degrade mixtures of n-alkanes as they occur in marine oil spills. However, investigations of growth behavior and physiology of these bacteria when cultivated with n-alkanes of different chain lengths (C6 to C30) as the substrates are still lacking. Growth rates increased with increasing alkane chain length up to a maximum between C12 and C19, with no evident difference between even- and odd-numbered chain lengths, before decreasing with chain lengths greater than C19. Surface hydrophobicity of alkane-grown cells, assessed by determination of the water contact angles, showed a similar pattern, with maximum values associated with growth rates on alkanes with chain lengths between C11 and C19 and significantly lower values for cells grown on pyruvate. A. borkumensis was found to incorporate and modify the fatty acid intermediates generated by the corresponding n-alkane degradation pathway. Cells grown on distinct n-alkanes proved that A. borkumensis is able to not only incorporate but also modify fatty acid intermediates derived from the alkane degradation pathway. Comparing cells grown on pyruvate with those cultivated on hexadecane in terms of their tolerance toward two groups of toxic organic compounds, chlorophenols and alkanols, representing intensely studied organic compounds, revealed similar tolerances toward chlorophenols, whereas the toxicities of different n-alkanols were significantly reduced when hexadecane was used as a carbon source. As one adaptive mechanism of A. borkumensis to these toxic organic solvents, the activity of cis-trans isomerization of unsaturated fatty acids was proven. These findings could be verified by a detailed transcriptomic comparison between cultures grown on hexadecane and pyruvate and including solvent stress caused by the addition of 1-octanol as the most toxic intermediate of n-alkane degradation.
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Zeng GM, Chen AW, Chen GQ, Hu XJ, Guan S, Shang C, Lu LH, Zou ZJ. Responses of Phanerochaete chrysosporium to toxic pollutants: physiological flux, oxidative stress, and detoxification. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:7818-7825. [PMID: 22703191 DOI: 10.1021/es301006j] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The white-rot fungus Phanerochaete chrysosporium has been widely used for the treatment of waste streams containing heavy metals and toxic organic pollutants. The development of fungal-based treatment technologies requires detailed knowledge of the relationship between bulk water quality and the physiological responses of fungi. A noninvasive microtest technique was used to quantify real-time changes in proton, oxygen, and cadmium ion fluxes following the exposure of P. chrysosporium to environmental toxic (2,4-dichlorophenol and cadmium). Significant changes in H(+) and O(2) flux occurred after exposure to 10 mg/L 2,4-dichlorophenol and 0.1 mM cadmium. Cd(2+) flux decreased with time. Reactive oxygen species formation and antioxidant levels increased after cadmium treatment. Superoxide dismutase activity correlated well with malondialdehyde levels (r(2) = 0.964) at low cadmium concentrations. However, this correlation diminished and malondialdehyde levels significantly increased at the highest cadmium concentration tested. Real-time microscale signatures of H(+), O(2), and Cd(2+) fluxes coupled with oxidative stress analysis can improve our understanding of the physiological responses of P. chrysosporium to toxic pollutants and provide useful information for the development of fungal-based technologies to improve the treatment of wastes cocontaminated with heavy metals and organic pollutants.
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Affiliation(s)
- Guang-Ming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, P.R. China.
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Singh R, Olson MS. Transverse mixing enhancement due to bacterial random motility in porous microfluidic devices. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:8780-8787. [PMID: 21877703 DOI: 10.1021/es201706w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Bacterial swimming in groundwater may create flow disturbances in the surrounding microenvironment thereby enhancing contaminant mixing. Porous microfluidic devices (MFDs) were fabricated in three different pore geometry designs: uniform grain size with large pore throats (MFD-I), nonuniform grain size with restricted pore space (MFD-II), and uniform grain size with small pore throats (MFD-III). Escherichia coli HCB33 was used to assess the effect of bacterial random motility on transverse mixing of a tracer, fluorescent labeled dextran, under three experimental conditions in which motile bacteria, nonmotile bacteria, and plain buffer suspensions were flown through the MFDs at four different flow rates. Mixing was quantified in terms of the best-fit effective transverse dispersion coefficient ((D(cy))(eff)). A mixing enhancement index (MEI) was defined as the ratio of the (D(cy))(eff) of tracer in experiments with motile bacteria and without bacteria. Motile bacteria caused a maximum 5-6 fold increase in MEI in MFD-II, a nearly 4-fold increase in MFD-I, and very little observed change in MFD-III. The apparent transverse dispersivities (α(app)) of MFD-II and MFD-I increased by 3 and 2.3 times, respectively, with no change in MFD-III. These observations indicate that both pore throat size and pore arrangement are critical factors for contaminant mixing in porous media.
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Affiliation(s)
- Rajveer Singh
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA
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16
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Laera G, Chong MN, Jin B, Lopez A. An integrated MBR-TiO2 photocatalysis process for the removal of Carbamazepine from simulated pharmaceutical industrial effluent. BIORESOURCE TECHNOLOGY 2011; 102:7012-7015. [PMID: 21558053 DOI: 10.1016/j.biortech.2011.04.056] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/17/2011] [Accepted: 04/18/2011] [Indexed: 05/30/2023]
Abstract
This paper aims to demonstrate that integrating biological process and photocatalytic oxidation in a system operated in recycling mode can be a promising technology to treat pharmaceutical wastewater characterized by simultaneous presence of biodegradable and refractory/inhibitory compounds. A lab-scale system integrating a membrane bioreactor (MBR) and a TiO(2) slurry photoreactor was fed on simulated wastewater containing 10mg/L of the refractory drug Carbamazepine (CBZ). Majority of chemical oxygen demand (COD) was removed by the MBR, while the photocatalytic oxidation was capable to degrade CBZ. CBZ degradation kinetics and its impacts on the biological process were studied. The adoption of a recycling ratio of 4:1 resulted in removal of up to 95% of CBZ. Effluent COD reduction, sludge yield increase and respirometric tests suggested that the oxidation products were mostly biodegradable and not inhibiting the microbial activity. These results evidenced the advantages of the proposed approach for treating pharmaceutical wastewater and similar industrial effluents.
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Affiliation(s)
- G Laera
- Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche, Viale De Blasio 5, 70132 Bari, Italy.
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17
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Lu YQ, Jiang JK, Huang WD. Clinical features and treatment in patients with acute 2,4-dinitrophenol poisoning. J Zhejiang Univ Sci B 2011; 12:189-92. [PMID: 21370503 DOI: 10.1631/jzus.b1000265] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To report clinical features and treatment of 16 cases of acute 2,4-dinitrophenol poisoning. METHODS A total of 16 patients suffering from acute poisoning due to non-oral exposure to 2,4-dinitrophenol were sent to our hospital. Two died within 3 h after admission, while the other 14 responded to supportive treatment and hemoperfusion. Clinical features and treatment of the patients were retrospectively analyzed and presented. RESULTS Fourteen patients recovered and were discharged after four to six weeks of treatment. No obvious poisoning sequelae were found in the three-month follow-up. CONCLUSIONS Non-oral exposure to 2,4-dinitrophenol is toxic. Hemoperfusion and glucocorticoid treatments may be efficient measures to prevent mortality, but this requires further study.
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Affiliation(s)
- Yuan-qiang Lu
- Department of Emergency, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
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18
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Ray S, Peters CA. Adaptations in microbiological populations exposed to dinitrophenol and other chemical stressors. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2010; 29:2161-2168. [PMID: 20872677 DOI: 10.1002/etc.280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Microbiological populations in natural and engineered systems may experience multiple exposures to chemical stressors, which may affect system functions. The impact of such exposures on the metabolism of a population of Pseudomonas aeruginosa was studied using respirometry. Two serial exposures to low concentrations of 2,4-dinitrophenol (DNP), pentachlorophenol (PCP), or N-ethyl maleimide (NEM) did not affect metabolism beyond that expected for a single exposure. However, at higher concentrations, three exposures to DNP led to a combination of metabolic stress and resilience in the population. At a low DNP concentration of 400 mg/L, multiple exposures led to increased stress but indicated no development of resilience. At a high DNP concentration of 1,200 mg/L, no biological activity was observed, indicating that the population did not survive the exposure. At intermediate concentrations of 800 and 900 mg/L DNP, stress was observed, but it was found to decrease after multiple exposures. This, combined with the observation that the size of the population decreased, indicated that resilience in the population had developed because of elimination of the weaker organisms in the population. In contrast, the lack of resilience at the lower DNP concentration was attributed to the survival of the strong as well as weak members, lowering the resilience of the population as a whole. The development of resilience within a window of stressor concentrations is an important finding with implications for predicting the performance of biotreatment processes and biosensor technologies and for interpreting ecotoxicity risk assessments.
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Affiliation(s)
- Sujata Ray
- Department of Civil Engineering, Indian Institute of Technology, Guwahati, Guwahati, Assam 781 039, India
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19
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McLamore ES, Zhang W, Porterfield DM, Banks MK. Membrane-aerated biofilm proton and oxygen flux during chemical toxin exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:7050-7057. [PMID: 20735036 DOI: 10.1021/es1012356] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Bioreactors containing sessile bacteria (biofilms) grown on hollow fiber membranes have been used for treatment of many wastestreams. Real time operational control of bioreactor performance requires detailed knowledge of the relationship between bulk liquid water quality and physiological transport at the biofilm-liquid interface. Although large data sets exist describing membrane-aerated bioreactor effluent quality, very little real time data is available characterizing boundary layer transport under physiological conditions. A noninvasive, microsensor technique was used to quantify real time (≈1.5 s) changes in oxygen and proton flux for mature Nitrosomonas europaea and Pseudomonas aeruginosa biofilms in membrane-aerated bioreactors following exposure to environmental toxins. Stress response was characterized during exposure to toxins with known mode of action (chlorocarbonyl cyanide phenyl-hydrazone and potassium cyanide), and four environmental toxins (rotenone, 2,4-dinitrophenol, cadmium chloride, and pentachlorophenol). Exposure to sublethal concentrations of all environmental toxins caused significant increases in O(2) and/or H(+) flux (depending on the mode of action). These real time microscale signatures (i.e., fingerprints) of O(2) and H(+) flux can be coupled with bulk liquid analysis to improve our understanding of physiology in counter-diffusion biofilms found within membrane aerated bioreactors; leading to enhanced monitoring/modeling strategies for bioreactor control.
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Affiliation(s)
- E S McLamore
- Physiological Sensing Facility, Purdue University, 1203 West State Street, West Lafayette, Indiana 47907-2057, USA.
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Singh R, Olson MS. Kinetics of trichloroethylene and toluene toxicity to Pseudomonas putida F1. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2010; 29:56-63. [PMID: 20821419 DOI: 10.1002/etc.14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The goal of the present study was to elucidate the distribution of viable bacteria in chemical gradients and to evaluate the toxic effect of high concentrations of contaminants on contaminant-degrading bacteria under prolonged exposure. Accumulations of viable Pseudomonas putida F1 (P. putida F1) cells were observed surrounding trichloroethylene (TCE)-containing plugs. Results from this work indicate that P. putida F1 immediately adjacent to a TCE source become nonviable, whereas cells accumulating farther away use chemotaxis to migrate toward regions with optimal chemical concentrations in the form of concentrated bacterial bands. A method was developed to test the toxicity of model contaminant stressors, TCE and toluene, to P. putida F1; data obtained from toxicity experiments were fit to linear and exponential bacterial viability-decay models. Toxicity of TCE to P. putida F1 was best described with an exponential viability-decay model, with a viability-decay constant k(TCE) = 0.025 h(-4.95) (r(2) = 0.965). Toluene toxicity showed a marginally better fit to the linear viability-decay model (r(2) = 0.976), with a viability-decay constant k(toluene) = 0.208 h(-1). Best-fit model parameters obtained for both TCE and toluene were used to predict bacterial viability in toxicity experiments with higher contaminant concentrations and matched well with experimental data. Results from the present study can be used to predict bacterial accumulation and viability near nonaqueous-phase liquid (NAPL) sources in groundwater and may be helpful in designing bioremediation strategies for sites contaminated with residual NAPLs.
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Affiliation(s)
- Rajveer Singh
- Department of Civil Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, USA
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