Klebsiella pneumoniae metabolites enhance Microcystis aeruginosa biomass flocculation

Microcystis aeruginosa is a common aquatic toxin-producing cyanobacterium. This study explores M. aeruginosa biomass recovery using bioflocculation. Bioflocculants produced by Klebsiella pneumoniae significantly enhanced aquatic M. aeruginosa flocculation efficiency. Under neutral and acidic conditions, flocculation efficiency reached 90%, whereas flocculation efficiency was 75% under alkaline conditions. M. aeruginosa flocculation was ion dependent, and Ca²⁺ was determined to be the most effective cationic inducer. Negatively charged proteoglycans were identified as the being the functional components in the flocculants. Optimal conditions for M. aeruginosa flocculation were determined using response surface methodology and are as follows: (1) K. pneumoniae bioflocculant dose, 13.3?mg/L; (2) flocculation time, 1.6 hours; and (3) pH?=?5 for flocculation of 10⁹ cells per litre. Bioflocculation using K. pneumoniae represents a promising method to control development of M. aeruginosa blooms. Further in-field investigations are necessary to fully assess its potential.     

Online single particle analysis of chemical composition and mixing state of crop straw burning particles: from laboratory study to field measurement

Fresh straw burning (SB) particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS). Based on the mass spectral patterns, the SB particles were clustered into four major types: Salt, Organic Carbon (OC), Elemental Carbon (EC), and internally mixed particles of EC and OC (EC-OC). In addition, particles containing ash, polycyclic aromatic hydrocarbons, heavy metals or nicotine were also observed. Physical and chemical changes of the SB particles immediately after the emission were analyzed with highly time-resolved data. During the aging processes, the average particle size increased steadily. Freshly emitted organic compounds were gradually oxidized to more oxygenated compounds in the OC-containing particles. Meanwhile, an important displacement reaction (2KCl+ SO42−→ K₂SO₄ + 2Cl⁻) was observed. The marker ions for SB particles were optimized and applied to identify the SB particles in the ambient atmosphere. The fluctuation of the number fraction of ambient SB particles sorted by ATOFMS agrees well with that of water soluble K⁺ measured by an online ion chromatography, demonstrating that the optimized marker ions could be good tracers for SB particles in field measurements.     

晶硅切割废砂浆回收企业废水处理工程实例

晶硅切割砂浆中含有聚乙二醇(PEG)和碳化硅,可回收资源。回收过程中产生的废水中仍然含有PEG和碳化硅,以致废水中悬浮物浓度较高、可生化性差。工程设计采用"预沉淀+混凝沉淀+气浮+催化氧化+A/O生化"处理工艺,经过5个月的调试运行,出水COD、SS可达GB 8978—1996《污水综合排放标准》三级标准。     

鲍鱼对2种多环芳烃的富集动力学研究

为探究多环芳烃(PAHs)在海洋生物体内富集过程,选择皱纹盘鲍(Haliotis discus hannai)作为受试生物,应用半静态双箱动力学模型,分别考察了3-甲基菲和9,10-甲基蒽2种多环芳烃在皱纹盘鲍体内的富集动力学过程,通过非线性拟合获得鲍鱼对2种多环芳烃的吸收速率常数(K_1)、释放速率常数(K_2)、生物富集因子(BCF),以及平衡状态下鲍鱼体内2种多环芳烃的含量(Cmax)、生物学半衰期(t_(1/2))等动力学参数。结果表明,鲍鱼对9,10-甲基蒽富集动力学参数K_1、K_2、BCF、Cmax、t_(1/2)的平均值分别为4.9437、0.406、13.59、790.03μg·L~(-1)、3.78 d。鲍鱼对3-甲基菲富集动力学参数K_1、K_2、BCF、Cmax、t_(1/2)的平均值分别为2.3023、0.367、5.97、354.37μg·L~(-1)、3.13 d。鲍鱼在不同浓度下对3-甲基菲和9,10-甲基蒽的生物富集过程均符合双箱动力学模型。     

微电解技术在工业废水处理中的应用进展

概述了近年来传统铁碳微电解法在难降解工业废水预处理、污泥处理和重金属去除、低浓度废水处理等领域的研究进展,介绍了通过在铁碳微电解体系中投加其他金属以催化反应的改性微电解法的废水处理效果,以及微电解与电场强化、微波强化、Fenton氧化、生物处理、物化法等其他工艺联合技术在废水处理中的应用现状,探讨了相关微电解技术存在的问题及未来的发展方向。     

Total versus urban: Well-to-wheels assessment of criteria pollutant emissions from various vehicle/fuel systems

The potential impact on the environment of alternative vehicle/fuel systems needs to be evaluated, especially with respect to human health effects resulting from air pollution. We used the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model to examine the well-to-wheels (WTW) emissions of five criteria pollutants (VOCs, NO_x, PM₁₀, PM_2.5, and CO) for nine vehicle/fuel systems: (1) conventional gasoline vehicles; (2) conventional diesel vehicles; (3) ethanol (E85) flexible-fuel vehicles (FFVs) fueled with corn-based ethanol; (4) E85 FFVs fueled with switchgrass-based ethanol; (5) gasoline hybrid vehicles (HEVs); (6) diesel HEVs; (7) electric vehicles (EVs) charged using the average U.S. generation mix; (8) EVs charged using the California generation mix; and (9) hydrogen fuel cell vehicles (FCVs). Pollutant emissions were separated into total and urban emissions to differentiate the locations of emissions, and emissions were presented by sources. The results show that WTW emissions of the vehicle/fuel systems differ significantly, in terms of not only the amounts but also with respect to locations and sources, both of which are important in evaluating alternative vehicle/fuel systems. E85 FFVs increase total emissions but reduce urban emissions by up to 30% because the majority of emissions are released from farming equipment, fertilizer manufacture, and ethanol plants, all of which are located in rural areas. HEVs reduce both total and urban emissions because of the improved fuel economy and lower emissions. While EVs significantly reduce total emissions of VOCs and CO by more than 90%, they increase total emissions of PM₁₀ and PM_2.5 by 35–325%. However, EVs can reduce urban PM emissions by more than 40%. FCVs reduce VOCs, CO, and NO_x emissions, but they increase both total and urban PM emissions because of the high process emissions that occur during hydrogen production. This study emphasizes the importance of specifying a thorough life-cycle emissions inventory that can account for both the locations and sources of the emissions to assist in achieving a fair comparison of alternative vehicle/fuel options in terms of their environmental impacts.     

Anogenital distance and its application in environmental health research

Anogenital distance (AGD), a useful anthropometric measurement for genital development in both animals and humans, was originally found by reproductive toxicologists in rodent experiments. As an easy-to-measure and sensitive marker, AGD has become a bioassay of fetal androgen action and a well-established reproductive toxicity endpoint in animals. It is generally accepted that AGD is sexually dimorphic in many mammals, with males having longer AGD than females. Exposure to proposed endocrine disruptors may result in reduced AGD; thus, it has been used to measure health effects of compounds with endocrine-altering properties or endocrine-disrupting chemicals (EDCs) in environmental toxicology. Moreover, AGD is an important clinical measure to address endocrine-sensitive endpoints in the first year of life and to assess the adverse impact of in utero exposure to environmental EDCs. Recently, AGD has been identified as one of the endpoints in the US Environmental Protection Agency guidelines for reproductive toxicity studies in humans, but use of AGD in human studies is still rare, and the results remain mixed and inconclusive due to many reasons. In order to achieve a breakthrough, researchers are endeavoring to standardize the measurement of AGD, normalize age-specific population data in different ethnic groups, and conduct more in-depth human researches in this field.     

城市的发展与火灾防治

随着经济的快速增长，火灾将会成为一个突出的灾害问题。作为经济发展中心的城市，火灾危险因素大大增加，因此，在城市的发展和改造过程中，应当同时抓好防火安全保障体系的建设，大力发展消防科技，并应加强防火安全教育，以便把火灾危害减少到最低限度     

光纤传输在地震台信号传输中的应用

深圳地震台处于强雷电干扰地区,雷电干扰的破坏给深圳地震台的各类设备带来严重的损害,造成较大的经济损失,后来在信号传输线路上改用了光纤传输,起到了明显的效果。作者将深圳台在应用光纤传输地震信号的实践工作进行简要总结,供一线台站的同行参考。     

南岭及其邻区多金属成矿条件与开发方向

本文在前人工作的基础之上,对南岭及其邻区的地层、岩浆岩、变质岩和构造综合研究与对比分析后认为,该区成矿条件优越,成矿条件复杂,表现出多金属矿产的共生性与伴生性。开发方向应该充分利用这两个特性,依靠科技,实行投资倾斜,减少资金沉淀,加强综合找矿、综合开采、综合冶炼、综合加工。在提高资源增值率,扩大经济效益的同时保护生态环境,完善产业结构与生产力布局,尽快地把该地区建成有色、稀有、黑色金属工业基地。