臭氧-BAF组合工艺对石化行业废水深度处理的中试研究

采用臭氧-曝气生物滤池（BAF）组合工艺对中石化九江分公司二级生化出水进行深度处理中试实验。探讨了臭氧投加量、进水水质冲击负荷等因素对该组合工艺出水COD、NH₄⁺-N的影响。中试结果表明,在该水质条件下,臭氧最佳投加量为20~25 mg/L;组合工艺处理后出水COD低于40 mg/L,NH₄⁺-N低于5 mg/L,达到中水回用设计标准;该组合工艺能够经受一定冲击负荷。     

Phthalate exposure in pregnant women and their children in central Taiwan

Phthalate exposure was found to be associated with endocrine disruption, respiratory effects, reproductive and developmental toxicity. The intensive use of plastics may be increasing the exposure to phthalates in Taiwanese population, particularly for young children.We studied phthalate metabolites in pregnant women and their newborns in a prospective cohort from a medical center in Central Taiwan. One hundred maternal urine samples and 30 paired cord blood and milk samples were randomly selected from all of participants (430 pregnant women). Eleven phthalate metabolites (MEHP, 5OH-MEHP, 2cx-MEHP, 5cx-MEPP, 5oxo-MEHP, MiBP, MnBP, MBzP, OH-MiNP, oxo-MiNP, and cx-MiNP) representing the exposure to five commonly used phthalates (DEHP, di-isobutyl phthalate (DiBP), DnBP, BBP, DiNP) were measured in urine of pregnant women, cord serum and breast milk after delivery, and in urine of their children. Exposure was estimated with excretion factors and correlation among metabolites of the same parent compound. Thirty and 59 urinary samples from 2 and 5 years-old children were randomly selected from 185 children successfully followed.Total urinary phthalate metabolite concentration (geometric mean, μg L⁻¹) was found to be higher in 2-years-olds (398.6) and 5-years-olds (333.7) than pregnant women (205.2). Metabolites in urine are mainly from DEHP. The proportion of DiNP metabolites was higher in children urine (4.39 and 8.31%, ages 2 and 5) than in adults (0.83%) (p < 0.01). Compared to urinary levels, phthalate metabolite levels are low in cord blood (37.45) and milk (14.90). DEHP metabolite levels in women’s urine and their corresponding cord blood are significantly correlated. Compared to other populations in the world, DEHP derived metabolites in maternal urine were higher, while phthalate metabolite levels in milk and cord blood were similar. The level of phthalate metabolites in milk and cord blood were comparable to those found in other populations. Further studies of health effects related to DEHP and DiNP exposure are necessary for the children.     

Chlorination of chlortoluron: kinetics, pathways and chloroform formation

Chlortoluron chlorination is studied in the pH range of 3-10 at 25 ± 1 °C. The chlorination kinetics can be well described by a second-order kinetics model, first-order in chlorine and first-order in chlortoluron. The apparent rate constants were determined and found to be minimum at pH 6, maximum at pH 3 and medium at alkaline conditions. The rate constant of each predominant elementary reactions (i.e., the acid-catalyzed reaction of chlortoluron with HOCl, the reaction of chlortoluron with HOCl and the reaction of chlortoluron with OCl⁻) was calculated as 3.12 (± 0.10) × 10⁷ M⁻² h⁻¹, 3.11 (±0.39) × 10² M⁻¹ h⁻¹ and 3.06 (±0.47) × 10³ M⁻¹ h⁻¹, respectively. The main chlortoluron chlorination by-products were identified by gas chromatography-mass spectrometry (GC-MS) with purge-and-trap pretreatment, ultra-performance liquid chromatography-electrospray ionization-MS and GC-electron capture detector. Six volatile disinfection by-products were identified including chloroform (CF), dichloroacetonitrile, 1,1-dichloropropanone, 1,1,1-trichloropropanone, dichloronitromethane and trichloronitromethane. Degradation pathways of chlortoluron chlorination were then proposed. High concentrations of CF were generated during chlortoluron chlorination, with maximum CF yield at circumneutral pH range in solution.     

Biodegradation and bio-sorption of antibiotics and non-steroidal anti-inflammatory drugs using immobilized cell process

In the present study, the removal mechanisms of four antibiotics (sulfamethoxazole, sulfadimethoxine, sulfamethazine, and trimethoprim) and four non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, ketoprofen, and naproxen) in immobilized cell process were investigated using batch reactors. This work principally explores the individual or collective roles of biodegradation and bio-sorption as removal routes of the target pharmaceuticals and the results were validated by various experimental and analytical tools. Biodegradation and bio-sorption were found as dominant mechanisms for the drug removal, while volatilization and hydrolysis were negligible for all target pharmaceuticals. The target pharmaceuticals responded to the two observed removal mechanisms in different ways, typically: (1) strong biodegradability and bio-sorption by acetaminophen, (2) strong biodegradability and weak bio-sorption by sulfamethoxazole, sulfadimethoxine, ibuprofen and naproxen, (3) low biodegradability and weak bio-sorption by sulfamethazine and ketoprofen, and (4) low biodegradability and medium bio-sorption by trimethoprim. In the sorption/desorption experiment, acetaminophen, sulfamethoxazole and sulfadimethoxine were characterized by strong sorption and weak desorption. A phenomenon of moderate sorption and well desorption was observed for sulfamethazine, trimethoprim and naproxen. Both ibuprofen and ketoprofen were weakly sorbed and strongly desorbed.     

Biotoxicity of nickel oxide nanoparticles and bio-remediation by microalgae Chlorella vulgaris

Adverse effects of manufactured nickel oxide nanoparticles on the microalgae Chlorellavulgaris were determined by algal growth-inhibition test and morphological observation via transmission electron microscopy (TEM). Results showed that the NiO nanoparticles had severe impacts on the algae, with 72 h EC(50) values of 32.28 mg NiOL(-1). Under the stress of NiO nanoparticles, C. vulgaris cells showed plasmolysis, cytomembrane breakage and thylakoids disorder. NiO nanoparticles aggregated and deposited in algal culture media. The presence of algal cells accelerated aggregation of nanoparticles. Moreover, about 0.14% ionic Ni was released when NiO NPs were added into seawater. The attachment of aggregates to algal cell surface and the presence of released ionic Ni were likely responsible for the toxic effects. Interestingly, some NiO nanoparticles were reduced to zero valence nickel as determined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The maximum ratios of nickel reduction was achieved at 72 h of exposure, in accordance with the time-course of changes in soluble protein content of treated C. vulgaris, implying that some proteins of algae are involved in the process. Our results indicate that the toxicity and bioavailability of NiO nanoparticles to marine algae are reduced by aggregation and reduction of NiO. Thus, marine algae have the potential for usage in nano-pollution bio-remediation in aquatic system.     

Use of reporter-gene based bacteria to quantify phenanthrene biodegradation and toxicity in soil

A phenanthrene-degrading bacterium, Sphingomonas paucimobilis EPA505 was used to construct two fluorescence-based reporter strains. Strain D harboring gfp gene was constructed to generate green fluorescence when the strain started to biodegrade phenanthrene. Strain S possessing gef gene was designed to die once phenanthrene biodegradation was initiated and thus to lose green fluorescence when visualized by a live/dead cell staining. Confocal laser scanning microscopic observation followed by image analysis demonstrates that the fluorescence intensity generated by strain D increased and the intensity by strain S decreased linearly at the phenanthrene concentration of up to 200 mg/L. Such quantitative increase and decrease of fluorescence intensity in strain D (i.e., from 1 to 11.90 ± 0.72) and strain S (from 1 to 0.40 ± 0.07) were also evident in the presence of Ottawa sand spiked with the phenanthrene up to 1000 mg/kg. The potential use of the reporter strains in quantitatively determining biodegradable or toxic phenanthrene was discussed.     

Transport of copper as affected by titania nanoparticles in soil columns

The effects of TiO₂ nanoparticles on the transport of Cu through four different soil columns were studied. For two soils (HB and DX), TiO₂ nanoparticles acted as a Cu carrier and facilitated the transport of Cu. For a third soil (BJ) TiO₂ nanoparticles also facilitated Cu transport but to a much lesser degree, but for a fourth soil (HLJ) TiO₂ nanoparticles retarded the transport of Cu. Linear correlation analysis indicated that soil properties rather than sorption capacities for Cu primary governed whether TiO₂ nanoparticles-facilitated Cu transport. The TiO₂-associated Cu of outflow in the Cu-contaminated soil columns was significantly positively correlated with soil pH and negatively correlated with CEC and DOC. During passage through the soil columns 46.6-99.9% of Cu initially adsorbed onto TiO₂ could be “stripped” from nanoparticles depending on soil, where Cu desorption from TiO₂ nanoparticles increased with decreasing flow velocity and soil pH.     

Adsorption of CO2 from flue gas streams by a highly efficient and stable aminosilica adsorbent

Three ordered mesoporous silicas (OMSs) with different pore sizes and pore architectures were prepared and modified with amine functional groups by a postgrafting method. The carbon dioxide (CO2) adsorption on these amine-modified OMSs was measured by using microbalances at 348 K, and their adsorption capacities were found to be 0.2-1.4 mmol g(-1) under ambient pressure using dry 15% CO2. It was found experimentally that the CO2 adsorption capacity and adsorption rate were attributed to the density of amine groups and pore volume, respectively. A simple method is described for the production of densely anchored amine groups on a solid adsorbent invoking direct incorporation of tetraethylenepentamine onto the as-synthesized OMSs. Unlike conventional amine-modified OMSs, which typically show CO2 adsorption capacity less than 2 mmol g(-1), such organic template occluded amine-OMS composites possessed remarkably high CO2 uptake of approximately 4.6 mmol g(-1) at 348 K and 1 atm for a dry 15% CO2/nitrogen feed mixture. The enhancement of 8% in CO2 adsorption capacity was also observed in the presence of 10.6% water vapor. Durability tests done by cyclic adsorption-desorption revealed that these adsorbents also possess excellent stability.     

微絮凝-直接过滤工艺用于东江流域典型印染废水回用的实验研究

以东莞地区某典型印染企业尾水为研究对象,针对东江流域饮用水源河流水质污染现状及纳污河流水质改善目标要求与企业对尾水回用的实际需求,进行了印染废水深度处理回用工艺的适用性研究.通过混凝烧杯实验,选用工业PACl、FeSO4、HPAC 3种药剂,对微絮凝-直接过滤集成工艺用于印染废水尾水深度处理后水质回用的可行性,进行了实...     

天津市污水再生利用经验与现状分析

对天津市污水再生利用发展现状进行了分析,总结了以双膜工艺为核心的天津污水再生利用工艺的运行管理经验.在上述基础上分析了天津市污水再生利用中存在的问题,并针对推动再生水产业发展提出总体对策,为我国再生水技术和行业的发展提供参考.