物联网技术在城市生活垃圾收运系统中的应用

我国的城市生活垃圾收运系统因其回收率低,监管难等问题,一直受到社会的广泛关注,而物联网技术因其可追溯性、动态性等特点,在解决该问题上表现出其显著优势。简要介绍了物联网技术的作用及其应用领域,总结了国内外基于物联网技术的城市生活垃圾收运情况,以我国上海市餐厨垃圾收运情况为案例,对其现状和目前存在的问题进行了总结,并结合物联网技术对餐厨垃圾信息化收运的管理方法进行了展望。     

电熨斗过热故障火灾痕迹特性的研究

通过火灾模拟实验,研究电熨斗发生过热故障后底板的火灾痕迹特性。根据底板的温度分布,应用DTA、TG、SEM、EDS、硬度分析和金相分析等方法,系统分析、归纳、总结电熨斗底板火灾痕迹的材料性能变化规律。研究表明,过热故障电熨斗的火灾痕迹,在宏观形貌、硬度分布和显微组织特征等方面,均显著区别于火烧电熨斗的火灾痕迹。结果为火灾原因调查提供新的技术依据,可应用在火灾现场勘验,物证提取与鉴定工作中。     

光合细菌两段流化床处理鸡粪粪水的研究

光合细菌对高浓度有机废水具有较好的适应性和处理能力,特别是作为一个预处理工艺对后续污水处理可以产生重要的影响。鉴于光合细菌生长时间相对较长,为提高光合细菌对高浓度有机污水的处理效率,本研究利用光合细菌两段流化床反应器对鸡粪粪水进行降解。试验结果表明:经过60 d的启动运行后,反应器进入稳定状态,在进水pH值6.0,COD小于10000mg/L范围内,流化床水力停留时间(HRT)为48 h时,对废水COD去除率为88.10%,TN去除率为68.29%,NH3-N去除率为94.42%,NO3-N去除率为65.43%。     

Sedimentary organic matter and bacterial community in microtidal mixed beaches of the Ligurian Sea (NW Mediterranean)

The quantity and quality of organic matter, and bacterial density and frequency of dividing cells were investigated in six microtidal mixed beaches of the Ligurian Sea (NW Mediterranean) to evaluate their main trophodynamic features. Concentrations of biopolymeric carbon (average 88.5?±?89.0 µgC/g) and the protein:carbohydrate ratio (on average lower than 1) were very low and classified these beaches as highly oligotrophic. The study of biochemical composition highlighted the nature of organic matter as being mainly refractory; furthermore, the quantitative differences observed along the across-beach gradient together with the unchanged pattern in qualitative features suggest that the organic matter in Ligurian beaches is prevalently of marine origin. This implies a negligible contribution of allochtonous and anthropogenic terrestrial input or in situ autochthonous production. Bacterial density displayed values ranging from 0.1–9.0 cell?×?10⁸/g DW in the top 2?cm layer and showed a significant correlation with the quantity of organic matter. In addition, the frequency of dividing cells showed a positive correlation with the protein:carbohydrate ratio, suggesting that the biochemical composition of organic matter also has an influence on the active bacterial fraction. Because of the exposed nature, a strong coupling was found between the beach and the marine systems, and this seems to be of fundamental importance in terms of material and energy supply for the beach ecosystem. A shortage within this linkage was observed in summer owing to the strong environmental constrains leading to a sort of “beach desertification” and to a marked oligotrophy. Summer also has an effect of smoothing for spatial variability occurring within the biochemical and microbiological variables among the different beaches. The linkage observed between the sea and the land is the main factor controlling the origin and nature of sediment organic matter in these beaches also regulating bacterial abundances and the frequency of dividing cells.     

Using T-RFLP technology to analyze bacterial diversity in the rhizospheric soils of tea tree at different ages北大核心CSCD

The rhizospheric soils of Tieguanyin at different ages were used as the study materials, and terminal-restriction fragment length polymorphism (T-RFLP) was used to analyze the changes in bacterial diversity. The results showed that the number of T-RFs, Simpson index, and Shannon index decreased significantly with the age of the tea tree. Results of correlation analysis showed that 9 T-RFs from the bacterial community were significantly and positively correlated with the age of the tea tree, and included 34 species of microbes belonging to 10 classes. The 34 microbes were divided into 6 types according to their functional attributes, and included pathogenic bacteria, bacteria that improved soil texture or inhibited pathogenic bacteria, and bacteria associated with the carbon, nitrogen, or sulfur cycles, in which the percentage of pathogenic bacteria was 58.82%. Seventeen T-RFs were significantly and negatively correlated with the age of the tea tree, and included 38 species of bacteria belonging to 12 classes. The 38 bacterial species were divided into 5 types according to their functional attributes, and included pathogenic bacteria, bacteria that improved soil quality or inhibited pathogenic bacteria, and bacteria associated with the carbon cycle or nitrogen cycle, in which all the others, barring the pathogenic bacteria, accounted for 78.95% of the bacterial population. In brief, the diversity and function of bacteria in the rhizospheric soil of tea tree changed significantly with the age of the tea tree, which provides a theoretical basis for studying the interactions of bacterial communities. © 2018 Science Press. All rights reserved.     

Isolation,identification, and the degradation characteristics of a BDE-47 degrading strain北大核心CSCD

In an effort to remove BDE-47 residues from the environment, a bacterial strain that is capable of utilizing BDE-47 as the sole carbon source was isolated and screened from soil collected from an e-waste recycling area in Tianjin to analyze the degradation properties. The strain was preliminarily identified as Enterobacter sp. according to a 16S rDNA gene sequence analysis. The strain degraded 35.8% of 525 μg/L of BDE-47 in 35 d when the initial concentration of bacteria was 7.1 × 105 cells/ mL. The product of the biodegradation of BDE-47 was BDE-28. The biodegradation of BDE-47 fit well with first-order kinetics, and its degradation kinetics was ln Ct = - 0.104t + 6.22. With the addition of an electron acceptor, such as Fe3+, SO4 2- and NO3 -, the BDE-47 degradation rate was significantly increased to 49.8%, 59.1%, and 67.3%, respectively. The above results revealed that the strain could degrade BDE-47, which is of importance in the application of environmental bioremediation of BDE-47. © 2018 Science Press. All rights reserved.     

Isolation,identification, and the degradation characteristics of a thiobencarb-degrading bacterium Bacillus sp. T2北大核心CSCD

Thiobencarb, a thiocarbamate herbicide, is widely used to control weeds in rice paddies. Screening for highly efficient thiobencarb-degrading bacteria is important for the bioremediation of thiobencarb-contaminated environments. The aim of this study was to isolate and identify highly efficient thiobencarb-degrading bacteria and to identify the degradation pathway and the degrading properties. The thiobencarb-degrading strain was isolated using methods of microbiological acclimation and enrichment and was then identified using a 16S rRNA phylogenetic analysis. The degrading properties of the isolated bacterium were determined by single-factor experiments, and the degradation products were identified using gas chromatography-mass spectrometry (GC-MS). A thiobencarb-degrading strain T2, which can utilize thiobencarb as the sole source of carbon for energy and growth, was isolated from paddy soil. Strain T2 degraded more than 98.3% of 0.4 mmol/L of thiobencarb within 36 h. It was preliminarily identified as Bacillus sp. T2 according to the 16S rRNA gene analysis and from its morphological, physiological, and biochemical characteristics. The metabolic products of the thiobencarb degradation for strain T2 were identified as 4-chlorobenzyl mercaptan, 4-chlorobenzaldehyde, and 4-chlorobenzoic acid by the GC-MS. Based on metabolite identification, it was speculated that thiobencarb degradation in strain T2 was initiated by the hydrolysis of the thioester bond to produce 4-chlorobenzyl mercaptan, which was further oxidized to 4-chlorobenzaldehyde and 4-chlorobenzoic acid. The thiobencarb degradation that was initiated by the hydrolysis of the thioester bond by strain T2 is a new metabolic pathway, which provides valuable research material and reliable experimental data for revealing the metabolic process and mechanism of thiobencarb microbial degradation in soil. The strain Bacillus sp. T2 has a very high degradation efficiency, suggesting it is a good prospect for microbial remediation in thiobencarb-polluted environments. © 2018 Science Press. All rights reserved.     

伊犁地区部分河流的水质标识指数

通过2004 - 2006年对伊犁地区的特克斯河、伊犁河的水质调查及水质标识指数和综合指数(WQI)的计算发现,DO、COD、TN、NH3-N、TP 5项指标在10个断面的空间分布上伊宁市区的2个断面水质最差,在时间上属8月最差,水质主要污染指标的排序依次为TP、TN、COD和NH3-N.     

Identifying factors that influence soil heavy metals by using categorical regression analysis: A case study in Beijing,China

A method was proposed to identify the main influence factors of soil heavy metals. The influence degree of different environmental factors was ranked. Parent material, soil type, land use and industrial activity were main factors. Interactions between some factors obviously affected soil heavy metal distribution. Identifying the factors that influence the heavy metal contents of soil could reveal the sources of soil heavy metal pollution. In this study, a categorical regression was used to identify the factors that influence soil heavy metals. First, environmental factors were associated with soil heavy metal data, and then, the degree of influence of different factors on the soil heavy metal contents in Beijing was analyzed using a categorical regression. The results showed that the soil parent material, soil type, land use type, and industrial activity were the main influencing factors, which suggested that these four factors were important sources of soil heavy metals in Beijing. In addition, population density had a certain influence on the soil Pb and Zn contents. The distribution of soil As, Cd, Pb, and Zn was markedly influenced by interactions, such as traffic activity and land use type, industrial activity and population density. The spatial distribution of soil heavy metal hotspots corresponded well with the influencing factors, such as industrial activity, population density, and soil parent material. In this study, the main factors affecting soil heavy metals were identified, and the degree of their influence was ranked. A categorical regression represents a suitable method for identifying the factors that influence soil heavy metal contents and could be used to study the genetic process of regional soil heavy metal pollution.     

Toxicity of various anions associated with methoxyethyl methyl imidazolium-based ionic liquids on Clostridium sp

We investigated the effects on the growth of the anaerobic bacterium, Clostridium sp., of the ionic liquid, 1-methoxyethyl-3-methyl imidazolium [MOEMIM]⁺, derived from imidazolium cation and paired with one of a variety of counter-ions, viz., tetrafluoroborate [BF₄]^-, hexafluorophosphate [PF₆]^-_, trifluoroacetate [CF₃COO]^-, bis(trifluoromethane)sulfonamide [Tf₂N]^-, methane sulfonate [OMS], and 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF₄]. These anions, in association with [MOEMIM]⁺ lowered the growth rate of the bacterium, showing the following trend: [Tf₂N]^- ≧ [PF₆]^- > [BF₄]^- > [CF₃COO]^- > [OMS]⁻. Anions incorporating fluorine were more toxic than those without it, and their toxicity rose with an increase in the number of fluorine atoms. Also, [MOEMIM]⁺[BF₄]^- was less toxic than [BMIM]⁺[BF₄]^-, probably due to the presence of a methoxyethyl functional group integrated in the cation side chain.