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991.
不同运行模式对同步脱氮除磷CAST工艺快速启动及其稳定维持的影响 总被引:1,自引:0,他引:1
以实际生活污水为处理对象,考察了传统进水/曝气和改良型分段进水的交替缺氧-好氧(A/O)2种运行模式对CAST工艺的快速启动及脱氮除磷性能稳定维持的影响。结果表明,传统进水/曝气运行模式下,系统达到最佳营养物去除性能所需启动时间30 d,稳定运行阶段TN平均去除80.66%,磷的去除率维持在66.30%左右;采用改良型交替运行模式,反应器达到稳定运行状态仅需18 d,系统稳定运行时TN平均去除81.36%,磷去除率稳定维持在90%以上,出水磷浓度在0.3 mg/L以下,出水水质达到国家污水综合排放标准一级A(GB8978-2002)。研究还发现,传统运行模式下,由低温引起的污泥沉降性能变差导致系统污泥严重流失,反应器几乎丧失污染物去除性能;而低温对交替运行模式下的反应器除磷性能几乎没有影响,总氮去除则因氨氮不完全硝化而大大降低。 相似文献
992.
表面活性剂改性4A分子筛对Cr(VI)的吸附行为 总被引:1,自引:0,他引:1
采用浸渍法对4A分子筛进行表面改性,通过引入阳离子表面活性剂,使4A分子筛表面附着季铵型阳离子,并与反离子Br-形成"阴离子交换膜",从而促使更多的Cr(VI)阴离子通过离子交换吸附到改性4A分子筛上,通过X-射线衍射(XRD)和傅里叶变换红外光谱(FTIR)对样品的物相结构和组成进行表征分析。研究表明,表面活性剂的类型和疏水碳氢链结构会影响4A分子筛的吸附能力,十八烷基三甲基溴化铵(OTAB)碳氢链长,在分子筛表面形成的双分子层密,对Cr(VI)的吸附量最大。采用准一级、准二级、Elovich和Bangham动力学模型对六价铬的吸附数据进行拟合,其中准一级动力学方程最符合十八烷基三甲基溴化铵改性分子筛的吸附行为。同时,分别从Langmuir和Redlich-Peterson等温吸附模型获得六价铬的最大吸附量为13.98 mg/g,且改性分子筛以均一表面吸附为主。 相似文献
993.
ZHENMEI LÜ HANG MIN NA LI TIEJUAN SHAO YANGFANG YE 《Journal of environmental science and health. Part. B》2013,48(6):821-832
The denaturing gradient gel electrophoresis (DGGE) method was applied to determine the relative genetic complexity of microbial communities in flooded paddy soil treated with herbicide quinclorac (3,7-dichloro-8-quinoline-carboylic acid). The results obtained showed a significant effect of quinclorac on the development of bacterial populations in soils contaminated with different concentrations of the herbicide at the early time after application. In general, however, the number of populations of the same soil sample treated with the same concentration of the quinclorac differed obviously with increasing incubation time within the early 8 weeks. The scale of differences in banding patterns-showed that the microbial community structures of the quinclorac-treated and non-quinclorac-treated soils were not significantly different after 21 weeks of incubation. Quantification, as demonstrated in this paper, was studied by establishing dose-response relationships. Significant pattern variations were quantified. Prominent DGGE bands were excised, cloned and sequenced to gain insight into the identities of predominant bacterial populations. The majority of DGGE band sequences were related to bacterial genera Clostridium, Sphingobacterium, Xanthomonas and Rhodococcus. 相似文献
994.
Achintya N. Bezbaruah Jay M. Thompson Bret J. Chisholm 《Journal of environmental science and health. Part. B》2013,48(6):518-524
Zero-valent iron nanoparticles (nZVI, diameter < 90 nm, specific surface area = 25 m2 g?1) have been used under anoxic conditions for the remediation of pesticides alachlor and atrazine in water. While alachlor (10, 20, 40 mg L?1) was reduced by 92–96% within 72 h, no degradation of atrazine was observed. The alachlor degradation reaction was found to obey first-order kinetics very closely. The reaction rate (35.5 × 10?3–43.0 × 10?3 h?1) increased with increasing alachlor concentration. The results are in conformity with other researchers who worked on these pesticides but mostly with micro ZVI and iron filings. This is for the first time that alachlor has been degraded under reductive environment using nZVI. The authors contend that nZVI may prove to be a simple method for on-site treatment of high concentration pesticide rinse water (100 mg L?1) and for use in flooring materials in pesticide filling and storage stations. 相似文献
995.
Jianshe Tang Min Zhang Guohua Cheng Ang Li Yitong Lu 《Journal of environmental science and health. Part. B》2013,48(8):707-712
Diethyl (carboxymethyl) phosphonate (DECP) was used as the hapten to develop an indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) for detecting organophosphorus pesticides (OPs). Conjugator of DECP with bovin serum albumin (BSA) was used as the immunogen for producing the polyclonal antibodies (PcAbs). Three antisera were obtained after the immune procedure. Characterization studies of the PcAbs indicated that the titer of antiserum-1 was highest in 3 antisera, and antiserum-1 had high affinity and specificity to the parathion, dichlorvos and pirimiphos. The IC-ELISA showed an IC50 of 0.428 μ g/mL with a detection limit of 0.0125 μ g/mL to parathion. The assay also indicated that the IC50 values of pirimiphos and dichlorvos were 0.331 μ g/mL and 1.25 μ g/mL respectively, and the detection limits of pirimiphos and dichlorvos were 0.0116 μ g/mL and 0.048 μ g/mL respectively. Recoveries of parathion, pirimiphos and dichlorvos spiked into water samples ranged from 90% to 160%. The results indicated that the ELISA could be a convenient and supplemental analytical tool for monitoring OPs residues in environmental water samples. 相似文献
996.
Agata Witczak Agnieszka Tomza-Marciniak 《Journal of environmental science and health. Part. B》2013,48(7):658-665
The aim of this study was to determine the concentration of organochlorine pesticides [HCH and isomers (α, β, γ), aldrin, dieldrin, endrin, heptachlor and heptachlor epoxide and DDT and its metabolites (op’-DDD, pp’-DDD, op’-DDT, pp’-DDE, pp’-DDT] in smoked fish. Analysis was made of 12 typical smoked fish products that are the most popular among customers from the city of Szczecin, Poland. Pesticide residues were found in all samples of smoked fish. The smoked sprat and cold-smoked Baltic salmon were the most contaminated smoked fish products in terms of chlorine pesticides. The sum of DDT metabolites ranged from 1.48 (smoked mackerel) to 35.53 ng/g wet weight (smoked sprat), with the lowest concentrations found for op’-DDT and the highest for pp’-DDE. The level of heptachlor epoxide isomer B was low and ranged from 0.06 ± 0.01 (smoked eel) to 0.27 ± 0.07 ng/g w.w. (smoked sprat). The content of heptachlor was 0.48–1.99 ng/g w.w. Concentration of endrin was higher compared to other pesticides, ranged from 1.50 (cold-smoked salmon fillet) to 16.84 ng/g w.w (hot-smoked warehou). The contamination of smoked products was significantly low and poses no risk to the health of consumers provided that they eat a diverse diet. The concentration of organochlorine pesticides in the analysed products was below the standards accepted in European countries. 相似文献
997.
Sayuri Shimazu Masaya Ohta Hideyuki Inui Yoshihiko Nanasato Hitoshi Ashida Hideo Ohkawa 《Journal of environmental science and health. Part. B》2013,48(8):750-756
The transgenic Arabidopsis plants carrying a recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system were generated for assays of polychlorinated biphenyl (PCB) congeners. The selected transgenic Arabidopsis plant XgD2V11-6 exhibited a correlation between uptake of PCB126 and PCB126-induced GUS activity. Also, the plants showed induced GUS activity towards the supplemental indole 3-acetic acid (IAA). Thus, the GUS assay may reflect induction by both endogenous and exogenous AhR ligands. When biosurfactants, MEL-B, produced in the culture of yeast isolated from plants were used for assays of PCB congeners in the transgenic Arabidopsis plants, they showed marked PCB126 dose-dependent and toxic equivalency factor (TEF) dependent GUS activities. The effects of biosurfactants were clearer when the plants were cultivated on soils containing PCB congeners for 7 days as compared with on soils for 3 days as well as in the medium for 3 days. Threfore, it was estimated that biosurfactants form micellae with PCB congeners, which are easily uptaken by the plants in a mode of passive diffusion, transport into the aerial parts and then induce GUS activity. 相似文献
998.
Dragan R. Milićević Verica B. Jurić Srđan M. Stefanović Slavica M. Vesković-Moračanin Saša D. Janković 《Journal of environmental science and health. Part. B》2013,48(8):781-787
This study was undertaken to compare two different analytical methods for the determination and confirmation of ochratoxin A (OTA) in blood serum, kidney and liver of pigs. Sample clean-up was based on liquid-liquid phase extraction. The detection of OTA was accomplished with high-performance liquid chromatography (HPLC) combined either with fluorescence detection (FL) or electro spray ionization (ESI+) tandem mass spectrometry (MS–MS). Comparative method evaluation was based on the investigation of 90 samples of blood serum, kidney and liver per animal originating from different regions of Serbia. The analytical results are discussed in view of the respective method validation data and the corresponding experimental protocols. In general, analytical data obtained with (LC–MS–MS) liquid chromatography electro spray tandem mass spectro metry detection offered comparable good results at the sub-ppb concentration level. The results indicate that the liquid chromatography electro spray tandem mass spectrometric (LC-MS/MS) method was more specific and sensitive for the analysis and confirmation of ochratoxin A in pig tissues then high pressure liquid chromatography (HPLC) method after methylation of OTA. 相似文献
999.
Bappaditya Kanrar Anjan Bhattacharyya 《Journal of environmental science and health. Part. B》2013,48(8):788-797
The photolysis of a rice herbicide Bispyribac sodium (Sodium 2, 6-bis [(4, 6-dimethoxypyrimidin-2-yl) oxy] benzoate) has been studied in different aqueous medium (distilled water, pond water and Irrigation water) under the influence of UV (λ max ≥ 250 nm) and sunlight in presence or absence of sensitizers (TiO2 and KNO3). The study was conducted under laboratory simulated condition which made it possible to evaluate the contribution of different factors viz. source of irradiation, solvent and sensitizers towards the photolysis of bispyribac sodium. The photodegradation proceeds via first order reaction Kinetics in all the cases. Five photo metabolites (M1-M5) were isolated in pure form by column chromatographic method from the irradiation system under UV influenced and TiO2 as sensitizer. From the different spectral data (IR, NMR, UV-VIS, Mass) the structure of these five metabolites were assigned as M1 (Phenol), M2 [2, 6-Dihydroxy benzoic acid], M3 [2, 6-bis [(4, 6 dimethoxypyrimidin-2yl) oxy] benzoic acid], M4 [2-(3-Hydroxy-phenoxy)-pyrimidine-4, 6-diol] and M5 as [2,4-Dihydroxy-3, 5-dimethoxy-6-(4-methoxy pyrimidine-2-yloxy)-benzoic acid]. Moreover, another six photometabolites (M6-M11) were identified from the different irradiation system on the basis of Micromass analysis. On the basis of MS/MS data analysis, the structure of these six photometabolites were assigned as M6 [2-(4, 6-Dimethoxy-pyrimidin-2-yloxy)-6-hydroxy-benzoic acid], M7 [2-Hydroxy-6-(4-hydroxy-6-methoxy-pyrimidin-2-yloxy)-benzoic acid], M8 [4, 6-Dimethoxy-pyrimidin-2-ol], M9 [6-Methoxy-pyrimidine-2, 4-diol], M10 [2-Hydroxy-6-(pyrimidin-2-yloxy)-benzoic acid] and M11 [2, 4, 6-Trimethoxy-pyrimidine]. The plausible Photodegradation pathways of bispyribac sodium in the present investigation were portrayed which proceeds via hydrolysis, hydrolytic cleavage, O-dealkylation, decarboxylation, dehydroxylation, O-alkylation and hydroxylation. 相似文献
1000.
Minna Wu Xinyu Li Huiwen Zhang Yinghui Cai Chenggang Zhang 《Journal of environmental science and health. Part. B》2013,48(3):222-228
A microcosm incubation study using an aquic brown soil from northeast China (a Cambisol in the UN Food and Agriculture Organization FAO Soil Taxonomy) was conducted to examine the effects of different concentrations (0, 50, 150, and 250 mg kg?1) of methamidophos (O,S-dimethyl phosphoramidothioato) on Pseudomonas, one of the most important gram-negative bacteria in soil. Amplified ribosomal DNA restriction analysis (ARDRA) was performed to study the Pseudomonas community structure, an in vitro assay was made to test the antagonistic activity of isolated Pseudomonas strains against soil-borne Rhizoctonia solani, a major member of the pathogens highly related to soil-borne plant diseases, and special primer amplification and sequencing were performed to investigate the diversity of phlD, an essential gene in the biosynthesis of 2, 4-diacetylphloroglucinol (2, 4-DAPG), which has biocontrol activity in phlD +isolates. With exposure to increasing methamidophos concentrations, the total number of soil Pseudomonas ARDRA patterns decreased significantly, but with less change in the same treatments over 1, 3, and 5 weeks of incubation. The number of isolated Pseudomonas strains with antagonistic activity against R. solani as well as the diversity and appearance frequency of the strains' phlD gene also decreased with increasing concentrations of methamidophos, especially at high methamidophos concentrations. Applying methamidophos could increase the risk of soil-borne plant diseases by decreasing the diversity of the soil Pseudomonas community and the amount of R. solani antagonists, particularly those with the phlD gene. 相似文献