Aerobic granulation of pure bacterial strain Bacillus thuringiensis

The objective of this study is to cultivate aerobic granules by pure bacterial strain, Bacillus thuringiensis, in a sequencing batch reactor. Stable granules sized 2.0–2.2 mm were formed in the reactor after a five-week cultivation. These granules exhibited excellent settling attributes, and degraded phenol at rates of 1.49 and 1.19 g phenol/(g VSS?d) at 250 and 1500 mg/L of phenol concentration, respectively. Confocal laser scanning microscopic test results show that Bacillus thuringiensis was distributed over the initial small aggregates, and the outer edge of the granule was away from the core regime in the following stage.     

Development and initial validation of an Aviation Safety Climate Scale

PROBLEM: A need was identified for a consistent set of safety climate factors to provide a basis for aviation industry benchmarking. METHOD: Six broad safety climate themes were identified from the literature and consultations with industry safety experts. Items representing each of the themes were prepared and administered to 940 Australian commercial pilots. RESULTS: Data from half of the sample (N=468) were used in an exploratory factor analysis that produced a 3-factor model of Management commitment and communication, Safety training and equipment, and Maintenance. A confirmatory factor analysis on the remaining half of the sample showed the 3-factor model to be an adequate fit to the data. DISCUSSION: The results of this study have produced a scale of safety climate for aviation that is both reliable and valid. IMPACT ON INDUSTRY: This study developed a tool to assess the level of perceived safety climate, specifically of pilots, but may also, with minor modifications, be used to assess other groups' perceptions of safety climate.     

Microbial safety control of compost material with cow dung by heat treatment

Various kinds of pathogenic bacteria derived from the intestinal tract of animals exist in compost material like cow dung.In order to sterilize the pathogenic bacteria completely in compost material,the cow dung was put into a heat treatment machine in pilot plan, and harmless condition in short time was examined.The results indicated,pathogenic indicator bacteria such as coliform bacteria, fecal coliform,Escherichia coli and salmonella were all 10~6 cfu/g dw at the beginning,died rapidly when cow dung temperature rose to above 50℃,and not detected at 54-68℃for 6-24 h heat treatment.Coliform bacteria and salmonella in heated cow dung were not detected by re-growth culture and enrichment culture examination.Moreover,it was hardly influenced on the fermentation ability of composting microbe,organic decomposition bacteria.During heat treatment,the mesophile decreased rapidly and the thermophile stabilized or increased,and the most of composting microbe were bacillus in cow dung by fluorescence microscope,this indicated that bacillus was dominator and composting microbe in composting process.     

Biodegradation of beet molasses vinasse by a mixed culture of micro organisms: Effect of aeration conditions and pH control

Upon aeration, the mixed microbial SCD ProBio OriginalTM culture may be used as the first stage in a two- or multi-stage system for the biodegradation of beet molasses vinasse.     

水盐环境对黄河口淡水湿地土壤碳、氮、磷生态化学计量特征的影响

碳(C)、氮(N)、磷(P)是土壤重要的营养元素,其生态化学计量特征可以反映土壤供肥能力和质量状况,在揭示生态系统稳态机制中具有重要作用.水盐环境对河口湿地生态化学计量特征具有重要影响,但土壤C、 N、 P生态化学计量特征对水盐环境变化的响应仍不清楚.以黄河口湿地为研究对象,采用土柱移位培养法,将淡水湿地土壤分别移位至不同潮滩部位(高潮滩、中潮滩和低潮滩)的盐沼湿地,研究水盐环境对C、 N、 P生态化学计量特征的影响.结果表明,移位23个月后,淡水湿地土壤含水量(SWC)和电导率(EC)与C、 N、 P生态化学计量特征均发生了不同程度的变化.土壤SWC在高潮滩和中潮滩降低(P<0.05),在低潮滩升高(P<0.05); EC在3种潮滩上均有不同程度的升高(P<0.05).土壤有机碳(TOC)和全氮(TN)在高潮滩显著降低(P<0.05),全磷(TP)则在中潮滩和高潮滩显著降低(P<0.05); C∶N在高潮滩和中潮滩及C∶P和N∶P在高潮滩显著降低(P<0.05); C、 N、 P生态化学计量比在低潮滩变化均不显著(P>0.05).水盐环境主要...     

Innovative method of culturing bdelloid rotifers for the application of wastewater biological treatment

• An innovative method of culturing bdelloid rotifer fed on flour was proposed. • Rotifer fed on flour grew faster than that fed on bacteria or Chlorella vulgaris. • The optimum mass culture conditions for rotifer fed on flour were investigated. • The cultured rotifer could improve sludge settleability in the SBR. This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers, which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biological treatment performance. A common bdelloid rotifer, Habrotrocha sp., in a wastewater biological treatment system was selected as the culture target. Rotifers fed on flour could reproduce faster than those fed traditional food such as Chlorella vulgaris or mixed bacteria. As a rotifer food, flour has the advantages of simple preparation, effortless preservation, and low cost compared to live Chlorella vulgaris or mixed bacteria, so it is more suitable for the mass culture of rotifers. The optimal rotifer culture conditions using flour as food were also studied. According to the experimental results, the recommended rotifer culture conditions are a flour particle size of 1 μm, a flour concentration of 6 × 10⁶ cell/mL, a temperature of 28℃, a pH level of 6.5 and salinity of 100–500 mg/L. In addition, the sludge volume index in the sequencing batch reactor (SBR) with the addition of cultured rotifers was 59.9 mL/g at the end of operation and decreased by 18.2% compared to SBR without rotifer, which indicates that the cultured rotifers still retained the function of helping to improve sludge settling. This function may be related to the rotifer’s role in inhibiting bacteria from producing loosely bound extracellular polymeric substances in the SBR.     

混合菌种在发酵法生物产氢中的协同作用

为探讨产氢发酵细菌混合培养时菌种间的协同作用,本研究在间歇试验条件下,分别考察以葡萄糖和复杂有机物(淀粉、牛肉膏、聚乙二醇乙二酸酯和胰蛋白胨)为底物时,5株HPB(B49、H1、LM12、LM11和B51)混合培养,高效HPB(B49)与3株非产氢发酵细菌(L10、拟3-2和芽孢1)分别混合培养,以及B49与活性污泥混合培养对产氢能力的影响.试验结果表明,混合菌种间协同作用发挥是有条件的.当利用葡萄糖发酵产氢时,菌种间对共同底物的竞争使其协同作用无法发挥,从而制约了高效产氢细菌(HPB)的产氢能力;而利用复杂有机物发酵产氯时,菌种间的协同作用得以发挥,并促进了高效HPB产氢能力的提高.同时提出,针对不同底物可以采用不同的培养方式.     

我国潜在顾客对城市美食的偏好与影响因素研究--基于网络关注度视角

通过收集网络关注度等数据,利用赫芬达尔—赫希曼指数、皮尔逊相关系数、多元回归分析等方法分析了我国31个省份潜在顾客对10个典型城市美食的偏好与影响因素。结果发现:①同一性别、年龄和地区的潜在顾客对不同城市美食偏好程度均不同,男性潜在顾客对美食的偏好程度略高于女性潜在顾客,美食的潜在顾客以中青年为主。②不同性别、年龄和地区的潜在顾客对同一城市美食的偏好也存在明显差异。③人们对美食的偏好程度与可支配收入之间存在正相关关系,与空间距离之间存在负相关关系。④地域文化、宗教信仰、气候等因素也会对潜在顾客的美食偏好产生影响。     

洪泽湖围栏养殖对表层沉积物重金属含量影响与生态风险评价

为探讨洪泽湖全湖沉积物重金属分布特征及围栏养殖对其影响,于2018年洪泽湖部分围栏拆除后,对洪泽湖不同区域（河口、湖心、围栏区、拆除区和外围区）表层沉积物中重金属含量、来源和空间分布特征进行分析,评估其生态风险.结果表明,洪泽湖表层沉积物中Cr、Ni、Cu、Zn、As、Cd和Pb含量均值分别为66.78、33.89、25.35、74.77、16.55、0.23和27.20mg ·kg^-1.采用地累积指数和Hakanson潜在生态风险指数对沉积物重金属污染现状和潜在生态风险程度的评价表明,除了As和Cd元素处于较轻污染程度,其余元素Cr、Ni、Cu、Zn和Pb均处于无污染;除Cd存在严重的潜在生态风险,其余元素均只有低水平潜在生态风险.结果表明围栏区、拆除区和外围区之间的重金属含量呈现递增趋势,并向湖心蓄积,拆除围栏并未在短时间内明显降低重金属含量.洪泽湖整体呈现低生态风险的状态,今后治理重点应是北部及东北部的表层沉积物堆积区和养殖区.     

基于文献计量与共词分析法的企业安全文化研究述评

为了揭示国内企业安全文化的研究现状,并为后续研究指明方向,采用文献计量分析法、共词分析法对选取的2 474篇文献进行分析并利用NetDraw软件输出关键词知识图谱。结果表明:企业安全文化的文献量与研究内容呈阶段性特征,以2002,2011年为界划分为3个阶段;研究机构众多且主要研究者的研究方向存在差异;研究重点集中在企业安全文化内涵与层次结构、建设与评价实证研究以及与其他变量的关系3个方面;存在研究行业过于集中,安全文化评价方法与现实存在“脱节”等问题。