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BACKGROUND Studies have shown that thiamine intake is associated with cervical cancer, but the relationship between thiamine and HPV infection remains unclear. In the present study, we used the National Health and Nutrition Examination Survey (NHANES) database to investigate whether HPV infection was associated with thiamine intake. MATERIAL AND METHODS A total of 13 471 women ages 18-59 years were selected from the NHANES database from 2003 to 2016. Using thiamine intake as the independent variable, HPV infection as the dependent variable, and sociodemographic data and other data as the covariates, we analyzed the relationship between thiamine and HPV infection by conducting a weighted logistic regression model in a cross-sectional research design. RESULTS The two-piecewise linear model indicated the inflection point of thiamine intake was 2.07 mg. On the left side of the inflection point, the difference in the thiamine intake of log2 conversion was related to the difference of 0.82 in HPV infection, which means that the increase of every 1 unit increase in thiamine intake is associated with the decrease of the HPV infection by 18%. On the right side of the inflection point, we did not observe a correlation between HPV infection and thiamine intake. CONCLUSIONS Thiamine intake is negatively correlated with HPV infection. Intake of an appropriate amount of thiamine can prevent HPV infection. The best preventive effect can be achieved when the intake is about 2 mg, and excessive intake will not increase the preventive effect.
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Análise de Dados , Inquéritos Nutricionais , Papillomaviridae/fisiologia , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Tiamina/administração & dosagem , Adulto , Feminino , Humanos , Modelos Lineares , Dinâmica não Linear , Tiamina/farmacologia , Estados Unidos/epidemiologiaRESUMO
Herbicide wastewater is one of tne industrial wastewater, it has high salt content, poor biodegradability, biodegradable characteristics. Nitrogen-containing organic compounds are dominated in dissolved organic matter and dissolved organic matter of wastewater, BOD: COD = 0.045, C:N:P = 692:426:1. Applying static headspace, purg and trap, solid-phase extraction, solid-phase microextraction and liquid-liquid extraction as pretreatment methods combined with gas chromatography/mass spectrometry (GC/MS), which qualitatively analyzed the organic components of the Atrazine, acetochlor herbicide production wastewater and researched the UV spectrum, three-dimensional fluorescence spectroscopy of the wastewater and its major pollutants. The study of GC/MS indicated that Wastewater contained chlorinated hydrocarbons, BTEX and triazines, amides herbicides etc. 38 kinds of volatile and semi-volatile organic compounds, atrazine and acetochlor herbicides accounted for 87. 99%. Affected monocyclic or heterocyclic substances, the ultraviolet absorption spectrum of the wastewater in 210-230 and 250-270 nm in that the amino group lead to the UV absorption red shift 20 nm. Wastewater generated 5 fluorescence peak in λ(ex)/λ(em) = 200-280/300-400 nm, such as a(225/305 nm), b(265/365 nm), c(275/305 nm), d(285/390 nm), e(320/375 nm). Based on three-dimensional fluorescence results of the different functional groups of the characteristics organic, fluorescent area of unsaturated bond is in λ(ex)/λ(em) = 215-230/290-340 nm, the main contribution of the fluorescent substance in the region were olefins, benzene, heterocyclic in the wastewater; fluorescent area of Phenolic hydroxyl and carbonyl is in λ(ex)/λ(em) = 270/300 nm, the main contribution of the fluorescent substance in the region were phenols, ketones.
Assuntos
Herbicidas , Águas Residuárias/análise , Poluentes da Água/análise , Atrazina , Fluorescência , Cromatografia Gasosa-Espectrometria de Massas , Extração Líquido-Líquido , Microextração em Fase Sólida , Espectrometria de Fluorescência , Toluidinas , Compostos Orgânicos VoláteisRESUMO
Petrochemical wastewater is of huge quantity released during the production and complicated contaminants of petrochemical wastewater will have immense negative impact on ecology environment. Three-dimensional excitation-emission matrix fluorescence(3D-EEM) was used to investigate the characteristic fluorescence of influent and effluent from each processing unit of Hydrolysis-acidification +A/O+ Contact-oxidation Process in a typical petrochemical wastewater treatment plant . The results showed that there were 4 fluorescence peaks named Peak A, Peak B, Peak D, Peak E in the spectrum chart of influent, they are around lambda(ex/lambda(em) = 220/300, 225/340, 270/300, 275/340 nm, the primary source of fluorescence organic matter(FOM) is industrial wastewater. The fluorescence intensity of each fluorescence peak was decreased, while location was unchanged in the effluent of Hydrolysis-acidification. Peak C appeared from the effluent of anaerobic tank at lambda(ex)/lambda(em) = 250/425 nm, then the fluorescence intensity of Peak C was enhanced in the effluent of aerobic tank. Peak A disappeared from the effluent of secondary sedimentation tank. The spectrum chart of the wastewater had no obvious variation after secondary sedimentation tank. The removal rate of FOM was expressed with the degradation percentage of the fluorescence intensity, the total FOM was reduced by 92.0% after processing, and the removal rate of the FOM fluoresce around Peak A, Peak B, Peak D, Peak E were 100.0%, 91.2%, 80.3%, 92.0% respectively. A volatile I(Peak B)/I(Peak E) value of influent but a relatively stable value of effluent demonstrated that the wastewater treatment plant operated steadily and the process has higher capacity in resistance to shock loading.
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Compostos Orgânicos , Eliminação de Resíduos Líquidos , Indústrias Extrativas e de Processamento , Petróleo , Espectrometria de Fluorescência , Águas ResiduáriasRESUMO
In view of synchronous fluorescence possessing the character of good selectivity, high sensitivity, less interference, etc. it can be used for simultaneous determination of multi-component mixtures of polycyclic aromatic hydrocarbons (PAHs). A new method of constant-wavelength synchronous fluorescence spectrometry to determine two naphthalene and phenanthrene of PAHs was developed in this study. The effect of different experimental conditions, such as different disolvents for character of fluorescence spectra and the choose of the optimal wavelength difference were studied. Experiment showed that the simultaneous indentification and quantitative determination of the two PAHs when delta lambda = 100 was chosen. The fluorescence intensity was linearly related to naphthalene and phenanthrene concentration in the range of 0.5-25.0 microg x L(-1) with correlation coefficient 0.999 5 and 0.999 7, respectively. The detection limits were all lower than 0.03 microg x L(-1), and the relative standard deviations for naphthalene and phenanthrene were 1.19% and 180% (n=7), respectively. Results show that the compounds can be analyzed qualitatively and quantitatively by synchronous fluorescence spectrometry.
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In the acetophenone degradation process by electro-Fenton, the variation trend of fluorescence characteristics of dissolved organic matter (DOM) in acetophenone synthetic wastewater was detected by excitation-emission matrix (EEM) fluorescence spectra. The fluorescence spectra characteristics of acetophenone were studied, and the fitting line of fluorescence intensity and acetophenone removal efficiency was discussed in detail. The results show that the locations of the two fluorescence centers of acetophenone synthetic wastewater are at lambda(Ex/Em) = 270/305 nm (Peak A) and lambda(Ex/Em) = 215/305 nm (Peak B), respectively, and the ratio of Peak A/Peak B is 1.22. In the electro-Fenton treatment process, firstly, acetophenone was decomposed into unsaturated fatty acid which had stronger fluorescence intensity, further, it was degraded into short-chain small molecular compounds which have weaker fluorescence intensity. Therefore, the fluorescence intensity of synthetic wastewater was increased at first and decreased afterwards in the entire 180 min electro-Fenton treatment process. The two-dimensional fluorescence peak at 285-375 nm of emission wavelength (at lambda(Ex) = 250 nm) had a good linear relationship with the removal efficiency of acetophenone, therefore, it could reflect effectively the removal efficiency of acetophenone in the whole electro-Fenton treatment process.
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The dissolved organic matter (DOM) of acrylonitrile-butadiene-styrene (ABS) resin wastewater was qualitatively analysed by gas chromatography with mass spectrometry(GC-MS), Fourier transform infrared spectrometer(FTIR) and three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy. The detected results shows that the GC-MS qualitatively analysed 21 dissolved organic pollutants, such as acetophenone, styrene, alpha, alpha-dimethyl-benzenemethanol, 3,3'oxybis-propanenitrile, 3, 3'-iminobis-propanenitrile, 3,3'-thiobis-propanenitrile, 3-(dimethylamino)-propanenitrile and 2-propenenitrile. The results of Fourier transform infrared spectrometer (FTIR) and three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy could examine and certify the accuracy and integrity for the qualitative analysis of GC-MS. The results of this study provides an important guiding role for the development of wastewater treatment process.
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In our previous study, we found that Shoutai pills could improve the embryo implantation rate as well as the levels of estrogen, progesterone and estrogen receptor in rats with stimulated ovulation. However, the mechanism is not clear. This study was designed to investigate the effect of Shoutai pills on the levels of Th1 and Th2 cytokines in rats with stimulated ovulation and the mechanism. The rat model of stimulated ovulation was established by combined injection of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG). Then the rats were randomly divided into model group (M), Shoutai pills group (S), progesterone group (P) and normal group (N). All the pregnant rats were treated from the first day. The S and P groups were administrated with gavage of Shoutai pills and injection of progesterone respectively, and N and M groups were given the same volume of normal saline and distilled water respectively. After treatment for 7 days, the animals were executed for serum and uterine tissues. The ELISA method was adopted to detect the contents of Th1 cytokines [interferon-γ (INF-γ), interleukin-2 (IL-2)] and Th2 cytokines (IL-4, IL-6, IL-10). The expression of leukemia inhibitory factor (LIF) and leukemia inhibitory factor receptor (LIFR) was detected by Western blotting and real-time PCR. As compared with N group, the expression levels of IFN-γ and IL-2 in M group were significantly increased, and those of IL-4, IL-6, IL-10, LIF and LIFR were significantly decreased (P<0.05). As compared with M group, the levels of IL-4, IL-6, IL-10, LIF and LIFR in S group were significantly increased (P<0.05), and those of IFN-γ and IL-2 were significantly decreased (P<0.05). It was suggested that Shoutai pills can increase the levels of IL-4, IL-6, IL-10, LIF and LIFR as well as reduce the levels of INF-γ and IL-2 in rats with stimulated ovulation. The Shoutai pills may improve endometrial receptivity and promote embryo implantation by maintaining the balance of Th1/Th2 cytokines.
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Citocinas/sangue , Citocinas/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Endométrio/efeitos dos fármacos , Células Th1/efeitos dos fármacos , Células Th2/efeitos dos fármacos , Animais , Endométrio/metabolismo , Feminino , Fator Inibidor de Leucemia/metabolismo , Masculino , Medicina Tradicional Chinesa/métodos , Ovulação/efeitos dos fármacos , Ovulação/metabolismo , Indução da Ovulação/métodos , Progesterona , Ratos , Ratos Wistar , Células Th1/metabolismo , Células Th2/metabolismoRESUMO
Two parallel biological aerated filters (BAF)-ozonation,named as number 1(feeding with FeSO4·7H2O) and number 2,were used to treat petrochemical secondary effluent.The effect of FeSO4·7H2O on COD and phosphorus removal by BAF-ozonation was studied.Molecular weight distribution,three-dimensional fluorescence scan and gas chromatography-mass spectrometry (GC-MS) were used to analyze water quality before and after BAF-ozonation.The results showed the average COD and TP concentrations were 82.91 mg·L-1 and 1.37 mg·L-1,respectively.When the dosage of FeSO4·7H2O was 9 mg·L-1,the average removal rates of COD and TP were 52.20% and 71.50%,respectively.The average COD removal rate in number 1 combined process was 17.15%,which was higher than that in number 2 combined process.The TP removal rate in number 1 combined process was increased by 51.81%.The percentage of dissolved organic matters with relative molecular weight less than 1×103 was 52% in the raw wastewater.However,the percentage increased to 75% when treated by number 1 combined process and the removal rate of various molecular weight organics was increased.Three-dimensional fluorescence analysis showed that the dosage of FeSO4·7H2O could improve the removal of fluorescent substances.GC-MS results showed that the number and concentration of organics were reduced after number 1 combined process in comparison with number 2 combined process.BAF-ozone could be enhanced by FeSO4·7H2O when treating petrochemical secondary effluent.
Assuntos
Reatores Biológicos , Filtração , Ozônio/química , Águas Residuárias , Análise da Demanda Biológica de Oxigênio , Cromatografia Gasosa-Espectrometria de Massas , Fósforo/isolamento & purificaçãoRESUMO
The dissolved organic matters from 2-buternal manufacture wastewater were fractionated into seven fractions by ultra-filtration membrane separation. The amounts and structural compositions of organic compounds in different molecular weight ranges were characterized by dissolved organic carbon (DOC), ultraviolet spectrum (UV), Fourier transform infrared spectrometer (FT-IR) and gas chromatography with mass spectrometry (GC-MS). The results showed that the fraction of molecular weight less than 1×103 had the largest proportion in the wastewater, and occupied 88.57% of the DOC. There were 27 kinds of compounds qualitatively analyzed by GC-MS, mainly including aldehyde, ketone, ester, alcohol, phenol, organic acid, alkane and other heterocyclic compounds. The proportions of compounds of peak area accounting for total peak area of organic matters were 6.9%, 5.3%, 35.4%, 13.2%, 4.6%, 0.4%, 1.7% and 16.8% respectively, adding up to 84%. The analysis of UV and FT-IR demonstrated that the spectral absorptive characteristics of organic compounds from different fractions were not significantly different. The fractions contained carbonyls, hydroxys and aromatic compounds, which was consistent with the qualitative analysis of GC-MS. The results of this study provide an important guidance for the development and optimization of 2-buternal manufacture wastewater treatment process.
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The anaerobically digested effluent of the dispersed swine wastewater was treated by a three-stage bio-zeolite constructed wetland, and the performance of the wetland, the variation of pollutants concentration in effluent and ORP distribution in the bio-zeolite layer were studied. The results showed that COD, N and P in the digested effluent could be efficiently removed by the wetland, and the wetland also had resistance to ammonia impact load. When the hydraulic loading rate was 0.047 m3·(m2·d)-1, COD, NH4+-N and TN (the average mass concentrations in inflow were 477.7, 155.3 and 176.4 mg·L-1) were mainly removed in the district 1 of the wetland, and the average removal rates were 80.6%, 55.3% and 58.1%, respectively. There was obvious enhancement of nitrification in the bio-zeolite, and the major nitrification product was nitrate. The mass concentrations of NO3--N in the district 1, district 2 and district 3 of the wetland were 85.85, 91.06 and 82.41 mg·L-1, respectively. The nitrate produced in bio-zeolite layer of the district 1 could be denitrified by microorganisms in the slag brick layer using the residual organic substances in water as the substrate. TP was mainly removed by adsorption in the slag brick layer, and the role of microbe assimilation was relatively small. The reaeration of the bio-zeolite layer in the three-stage wetland was good. Most of the ORP values remained over 400 mV in the bio-zeolite layer.
Assuntos
Nitrificação , Eliminação de Resíduos Líquidos , Purificação da Água , Áreas Alagadas , Zeolitas/química , Animais , Nitrogênio , Suínos , Águas ResiduáriasRESUMO
Fenton oxidation was applied to treat the petrochemical treatment plant secondary effluent by the continuous flow configuration. The effect of Fenton agent dosage on the COD and phosphorus removal and the variation of the dissolved organic matter characteristics during the treatment process were investigated. The results showed the average COD and PO(4)3- -P concentrations were 64.8 mg.L-1 and 0. 79 mg.L-1, respectively. When the dosage of H2O (30%), FeSO4.7H2O and PAM were 0. 4 mL.L-1, 0. 8 mg.L-1 and 0. 9 mg.L-1 and the residence time was 30 min, the average removal rate of COD and PO(4)3- -P were 24. 3% and 95. 5% respectively. The effluent COD was lower than 50 mg.L-1. The percentage of dissolved organic matters with molecular weight less than 1 x 10(3) was 80. 4% in the raw wastewater, however, the percentage increased to 95. 6% when treated by Fenton oxidation. Three-dimensional fluorescence analysis showed that the Fenton oxidation can effectively remove protein and phenols. GC-MS results showed that there were about 117 kinds of organic matters detected in the secondary effluent, while the number reduced to 27 after oxidation by Fenton. The organics containing unsaturated bond had a better removal than those of other types of organics. Fenton oxidation can be used in the advanced treatment of petrochemical secondary effluent.
Assuntos
Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/química , Recuperação e Remediação Ambiental , Indústrias Extrativas e de Processamento , Fluorescência , Cromatografia Gasosa-Espectrometria de Massas , Peróxido de Hidrogênio , Resíduos Industriais , Ferro , Peso Molecular , Oxirredução , Fenóis/isolamento & purificação , Fósforo/isolamento & purificaçãoRESUMO
Micro-aerobic hydrolysis acidification technology was applied in the reconstruction of ananaerobic hydrolysis acidification tank in a north petrochemical wastewater treatment plant. After put into operation, the monitoring results showed that the average removal rate of COD was 11.7% when influent COD was 490.3-673.2 mg x L(-1), hydraulic retention time (HRT) was 24 and the dissolved oxygen (DO) was 0.2-0.35 mg x L(-1). In addition, the BOD5/COD value was increased by 12.4%, the UV254 removal rate reached 11.2%, and the VFA concentration was increased by 23.0%. The relative molecular weight distribution (MWD) results showed that the small molecule organic matter (< 1 x 10(3)) percentage was increased from 59.5% to 82.1% and the high molecular organic matter ( > 100 x 10(3)) percentage was decreased from 31.8% to 14.0% after micro-aerobic hydrolysis acidification. The aerobic biodegradation batch test showed that the degradation of petrochemical wastewater was significantly improved by the pretreatment of micro-aerobic hydrolysis acidification. The COD of influent can be degraded to 102.2 mg x L(-1) by 48h aerobic treatment while the micro-aerobic hydrolysis acidification effluent COD can be degraded to 71.5 mg x L(-1) on the same condition. The effluent sulfate concentration of micro-aerobic hydrolysis acidification tank [(930.7 ± 60.1) mg x L(-1)] was higher than that of the influent [(854.3 ± 41.5) mg x L(-1)], indicating that sulfate reducing bacteria (SRB) was inhibited. The toxic and malodorous gases generation was reduced with the improvement of environment.
Assuntos
Bactérias Redutoras de Enxofre , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Biodegradação Ambiental , Hidrólise , Oxigênio/análise , Sulfatos/análise , Instalações de Eliminação de Resíduos , Microbiologia da ÁguaRESUMO
The Mann-Whitney U test method was used to analyze the species sensitivity to ammonia toxicity. And based on the analysis, the relationship between species selection method and WQC deriving method was studied by using toxicology, biological taxonomy and sampling-inference theory. Results showed that vertebrate species, especially the Actinopterygii, accounted for the vast majority in the toxicity test species. And the species composition of toxicity test species was inconsistent with the species composition of the ecosystem. Sensitivity to ammonia toxicity among different taxa varied significantly for most species except some species in individual taxa, especially the less sensitive species. The variable coefficient of interspecies decreased with the reduction of biological classification level. To a certain extent, it showed that the species sensitivities in the same taxa to toxicant were more similar than those in different taxa. According to sampling-inference theory, the WQC for aquatic life deriving method belonged to the design-based inference. And taxonomic groups could be used as auxiliary variables to conduct a stratifactory sampling for species selection in WQC deriving which could improve the sampling efficiency and precision.
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Biota , Monitoramento Ambiental/métodos , Testes de Toxicidade/métodos , Qualidade da Água/normas , Amônia/toxicidade , Animais , Peixes , Poluentes Químicos da Água/toxicidadeRESUMO
Petrochemical wastewaters have toxic impacts on the microorganisms in biotreatment processes, which are prone to cause deterioration of effluent quality of the wastewater treatment plants. In this study, the inhibition effects of activated sludge's oxygen consumption were tested to evaluate the toxicity of production wastewaters in a petrochemical industrial park. The evaluation covered the wastewaters from not only different production units in the park, but also different production nodes in each unit. No direct correlation was observed between the toxicity effects and the organic contents, suggesting that the toxic properties of the effluents could not be predicted by the organic contents. In view of the variation of activated sludge sensitivity among different tests, the toxicity data were standardized according to the concentration-effect relationships of the standard toxic substance 3, 5-dichlorophenol on each day, in order to improve the comparability among the toxicity data. Furthermore, the Quality Emission Load (QEL) of corresponding standard toxic substance was calculated by multiplying the corresponding 3, 5-dichlorophenol concentration and the wastewater flow quantity, to indicate the toxicity emission contribution of each wastewater to the wastewater treatment plant. According to the rank list of the toxicity contribution of wastewater from different units and nodes, the sources of toxic wastewater in the petrochemical industrial park were clearly identified. This study provides effective guidance for source control of wastewater toxicity in the large industrial park.
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Resíduos Industriais/análise , Esgotos/análise , Águas Residuárias/análise , Clorofenóis/análise , Indústrias Extrativas e de ProcessamentoRESUMO
Poly-butylenes succinate (PBS) was used as solid denitrification carbon source and biofilm carrier, to investigate the denitrification performance and the influence of adding inert carrier. The experimental results showed that PBS could serve as solid carbon source for denitrification of low C/N ratio wastewater, but the startup time was longer, about 33 d. There was no accumulation of nitrite nitrogen in the process of denitrification, but it produced less than 0.8 mg x L(-1) ammonia nitrogen. Increasing the amount of biofilm in PBS supported denitrification system by adding the inert carrier could improve the denitrification rate. The denitrification rates of PBS, PBS + 30 g gravel, PBS + 60 g gravel and PBS +90 g gravel systems were 5.33, 7.04, 10.05 and 6.93 mg x (L x h)(-1), respectively, and all reactions were zero order. During the denitrification process (0-9 h), DOC increased before it was reduced. At the end of the denitrification reaction (24 h), DOC of the denitrification system with inert carrier 60 g gravel and 90 g gravel was 16.34 mg x L(-1) and 19.22 mg x L(-1), respectively, higher than that without gravel of 13.48 mg x L(-1). The pH of all denitrification systems were lower than the initial value, which was the result of comprehensive function of acidic substances and alkalinity produced in the process of degradation of solid carbon source and denitrification, respectively.
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Biofilmes , Carbono/química , Desnitrificação , Succinatos/química , Águas Residuárias , Purificação da Água/métodos , Reatores Biológicos , Nitritos/química , Nitrogênio/químicaRESUMO
The advanced treatment of petrochemical secondary wastewater by ozone- aerated biological filter was carried out in this study. The effect of pH on ozonation and the removal of COD and UV254 by the ozone-aerated biological filter combined process were investigated. In addition, the variation of relative molecular mass distribution of organics and the characteristics of three-dimensional fluorescence spectra of the wastewater were also investigated. The results showed that the suitable operating conditions of the ozonation unit were: ozone dosage 10 mg x L(-1), contact time 4 min and slightly alkaline pH. Ozonation can transfer macromolecular organics into small molecular organics, resulting in a 15% increase in the percentage of the organics with small relative molecular mass (less than 1 000). The biodegradability of the petrochemical secondary effluent was significantly improved by ozonation, making it more suitable for the treatment by aerated biological filter. The removal efficiency of COD and UV254 were 40.8% and 45.8% when the hydraulic retention time was 3 hours and the gas to water ratio was 3:1 for BAF. The average COD of the petrochemical wastewater was 86.5 mg x L(-1) while the average COD of the effluent of the combined process was 49.4 mg x L(-1) when it was operated under optimal conditions.
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Filtração/métodos , Ozônio/química , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Indústrias Extrativas e de Processamento , Águas Residuárias/químicaRESUMO
The toxicity sensitivity of different freshwater aquatic organisms was analyzed using the collected toxicity data in this paper. Three methods were used to estimate the criteria of nitrate to protect the freshwater aquatic life. The results showed that the species sensitivity to nitrate followed the order of Arthropoda > Mollusca > Chordata, and Crustacea > Insecta > Gastropoda > Bivalvia > Amphibia > Actinopterygii. Moreover, the output of assessment factor method, species sensitivity distribution method and USEPA's method was significantly different. Finally, criterias of 87.97 mg x L(-1) and 5.17 mg x L(-1) to protect aquatic life from acute and chronic toxicity were proposed using USEPA's method.
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Organismos Aquáticos/efeitos dos fármacos , Monitoramento Ambiental , Nitratos/toxicidade , Poluentes Químicos da Água/toxicidade , Qualidade da Água , Animais , Água Doce/químicaRESUMO
The granulation of activated sludge was investigated using two parallel sequencing batch reactors (SBRs) operated in biological nitrogen and phosphorus removal conditions though the reactor configuration and operating parameters did not favor the granulation. Granules were not observed when the SBR was operated in biological nitrogen removal period for 30d. However, aerobic granules were formed naturally without the increase of aeration intensity when enhanced biological phosphorus removal (EBPR) was achieved. It can be detected that plenty of positive charged particles were formed with the release of phosphorus during the anaerobic period of EBPR. The size of the particles was about 5-20 µm and their highest positive ζ potential was about 73 mV. These positive charged particles can stimulate the granulation. Based on the experimental results, a hypothesis was proposed to interpret the granulation process of activated sludge in the EBPR process in SBR. Dense and compact subgranules were formed stimulated by the positive charged particles. The subgranules grew gradually by collision, adhesion and attached growth of bacteria. Finally, the extrusion and shear of hydrodynamic shear force would help the maturation of granules. Aerobic granular SBR showed excellent biological phosphorus removal ability. The average phosphorus removal efficiency was over 95% and the phosphorus in the effluent was below 0.50 mg L(-1) during the operation.
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Reatores Biológicos/microbiologia , Fósforo/isolamento & purificação , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Fenômenos Fisiológicos Bacterianos , Nitrogênio/isolamento & purificação , Purificação da Água/métodosRESUMO
A multi-stage microaerobic biological fluidized bed reactor was used for the pretreatment of synthetic wastewater containing high concentration of acrylic acid (AA). The effect of influent load was investigated and the intermediate products of acrylic acid degradation were analyzed. It indicated that the removal rate of AA was above 95% with effluent acrylic acid less than 150 mg x L(-1) and COD removal rate of 15%-30%, under the following conditions: hydraulic retention time of 12 h, waste water temperature of 25 degrees C, influent acrylic acid concentration of 3 000-9 000 mg x L(-1), volume load of 6.0-18.0 kg x (m3 x d)(-1). The main intermediate products of acrylic acid degradation were acetic and propionic acids. The multi-stage microaerobic biological fluidized bed reactor can transform each 1.00 mol acrylic acid into 0.22 mol acetic acid and 0.36 mol propionic acid, and achieve the pretreatment of acrylic acid wastewater at high loads.
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Acrilatos/isolamento & purificação , Reatores Biológicos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Acrilatos/metabolismo , Aerobiose , Biodegradação AmbientalRESUMO
To resolve the shortage of carbon source during traditional denitrification used to treat secondary effluent of acrylic fiber wastewater, tri-stage biofilm reactor was used, the influence of pH of influent, HRT, and NH4(+) -N concentration in raw water on NH4(+) -N removal was investigated. Efficiency of TN removal was also investigated. It demonstrated that the optimal HRT and pH were 24 hours and 7.8-8.0 respectively. Under these conditions the removal efficiencies of NH4(+) -N and TN were 94. 6% and 53% respectively. And the removal efficiency of NH4(+) -N had no relationship with the concentration of the inflow water. With absence of organic carbon source in the reactor, efficiency of TN removal was obvious, the average and the highest removal efficiencies of TN were 53% and 66% respectively, efficiency of secondary effluent of acrylic fiber wastewater nitrogen removal was obvious when treated with Tri-stage biofilm reactor.