固定化Acinetobacter sp. XA05和Sphingomonas sp. FG03降解苯酚

从活性污泥和受苯酚污染的土壤中分离出的菌株XA05和FG03均具有很强的苯酚生物降解能力。16srDNA序列分析表明,XA05和FG03菌株分别属于不动杆菌属(Acinetobacter sp.)和鞘氨醇单胞菌属(Sphin-gomonas sp.)。实验结果表明,在苯酚初始质量浓度为800.0mg/L、培养时间为35h的条件下,自由悬浮细胞和固定化细胞的苯酚降解率均高于95.0%。     

Remediation of DDT‐contaminated soil using optimized mixtures of surfactants and a mixing system

Soil contaminated with persistent pesticides, such as DDT, poses a serious risk to humans and to wildlife. A surfactant‐aided soil‐washing technique was studied as an alternative method for remediation of DDT‐contaminated soil. An ex situ soil washing method was investigated using nonionic and anionic surfactants due to the clayey structure of the contaminated soil. A mixture of 1 percent nonionic surfactant (Brij 35) and 1 percent anionic surfactant (SDBS) removed more than 50 percent of DDT from soil in a flow‐through system, whereas individual surfactants or other combinations of the surfactants had a lower removal efficiency. The soil‐washing technique was improved using a mixing system. The mixture of surfactants was optimized in the mixing system, and the combination of 2 percent Brij 35 and 0.1 percent SDBS was found to be optimum, removing 70 to 80 percent of DDT. Prewashing of the soil with tap water decreased the adsorption of surfactants to soil particles by 30 to 40 percent, and postwashing recovered 90 percent of the surfactants. © 2010 Wiley Periodicals, Inc.     

港东联合站外排污水深度处理工艺研究

为解决港东联合站外排污水2010年前达标排放的问题,需在现有氧化塘生化处理工艺的基础上,进行工艺优化和深度处理。通过对港东联合站外排污水的分析,发现现有处理系统的问题,并结合水质特性和现有处理工艺进行试验研究。结果表明:采用曝气生物滤池工艺,以兼性塘进水为水源,流量150L/h,BAF对CODCr的去除率为68.1%;采用活性炭吸附技术,在水力负荷不超过2.1m3/(m2.h)情况下,活性炭出水CODCr平均值为27.3～37.4mg/L,对CODCr的去除率在60%以上;曝气生物滤池与活性炭吸附工艺对CODCr、石油类、悬浮物的处理指标都达到了天津市地方标准DB12/356-2008《污水综合排放标准》的要求。     

Development of a fuzzy-stochastic nonlinear model to incorporate aleatoric and epistemic uncertainty

Site uncertainties significantly influence groundwater flow and contaminant transport predictions. Aleatoric and epistemic uncertainty are both identified in site characterization and represented using proper uncertainty theories. When one theory best represents one parameter whereas a different theory may be more suitable for another parameter, the hybrid propagation of aleatoric (random) and epistemic (nonrandom) uncertainties will occur. The computational challenges of joint propagation of aleatoric and epistemic uncertainty through groundwater flow and contaminant transport models are significant. A fuzzy-stochastic nonlinear model was developed in this paper to incorporate these two types of uncertain site information and reduce the computational cost. The results show that (1) the computational cost using the nonlinear model is reduced compared with that of using the sparse grid algorithm and Monte Carlo methods; (2) the uncertainty of hydraulic conductivity (K) significantly influences the water head and solute distribution at the observation wells compared to other uncertain parameters, such as the storage coefficient and the distribution coefficient (K_d); and (3) the combination of multiple uncertain parameters substantially affects the simulation results. Neglecting site uncertainties may lead to unrealistic predictions.     

溶胶-凝胶法制备复合光催化剂（MWNTs/TiO_2）工艺条件的研究

以多壁碳纳米管（MWNTs）为载体,在煅烧温度200~900℃、煅烧时间1~7 h、溶胶体系pH值为2~10的工艺条件下,采用溶胶-凝胶法制备复合光催化剂（MWNTs/TiO2）。通过其对甲基橙的光催化降解效果对比,评价各种复合光催化剂催化活性之间的差异,结果表明,随着煅烧温度的升高,复合光催化剂中纳米TiO2的晶型由锐钛型逐渐向金红石型转变,500℃时为2种晶型的混合相;pH值为2的强酸性条件有利于形成金红石晶型,pH值为5的中性及弱酸性条件则有利于形成锐钛型,而pH值为3时为2种晶型的混合相;在煅烧温度500℃、煅烧时间3 h、溶胶凝胶体系pH值为3的最佳制备工艺条件下,复合光催化剂催化活性最高,借助扫描电镜发现其TiO2均匀地包覆在多壁碳纳米管管壁上。     

试析安全“顽疾”症状及其治理对策

安全生产是一个永恒的主题,安全是最大的效益、安全是最大的和谐,是每一名职工、每一个家庭的共同期盼。综合分析大多数事故的内在原因,发现大部分是由“三违”引起和造成的。根据“三违”发生的原因、性质、动机、心理等特点,归纳为十种典型临床症状：     

工程技术管理人员安全生产责任的落实

安全生产责任制度,是现代企业工程施工安全生产工作的基本制度,是落实企业安全生产主体责任、规范安全管理流程的基本法则。每一个建筑施工企业都会制定出从企业董事长、总经理到各个管理岗位,直到基层作业人员的安全生产责任制。在施工现场安全生产工作中,工程技术人员的安全责任落实是安全管理链条的重要环节。     

Nitrogen loss through lateral seepage in near-trench paddy fields

A near-trench paddy field experiment with five urea application rates (0-360 kg N ha(-1) in 90-kg increments) was conducted on a paddy soil in the Taihu Lake Region of China to elucidate N losses through lateral seepage during three rice (Oryza sativa L.) growing seasons. The total N (Nt), NH4(+) -N, and NO3(-) -N concentrations in the lateral seepage water increased with increasing N rates. The seasonal Nt fluxes by lateral seepage varied from 6.8 to 25.6 kg N ha(-1) for urea application rates of 90 to 360 kg N ha(-1). Lateral seepage accounted for 4.7 to 6.6% of the Nt applied, implying that lateral seepage was an important pathway of N loss from near-trench paddy fields. The cumulative N loss via lateral seepage was significantly related to N fertilization rate (P = 0.05). Floodwater level was also identified as a main factor affecting N losses via lateral seepage from paddy fields, as indicated by a positive linear relationship (R2 = 0.43) between floodwater level and daily lateral flow during the flooded period (P = 0.05). Under the conditions of these experiments, a shallow floodwater depth of 50 mm, urea application rates of 90 kg N ha(-1) or less, and no rainfall within 1 wk after N application reduced N losses by lateral seepage from paddy fields.     

Adsorption of Pb and Cd on the natural surface coatings (NSCs) in the presence of organochlorine pesticides: a preliminary investigation

Adsorption of Pb and Cd in the presence and absence of organochlorine pesticides (OCPs) on natural surface coatings (NSCs), which were collected in the Nanhu Lake in Changchun, China, was measured in order to investigate the effect of the OCPs on the adsorption of heavy metals on the NSCs. Adsorption of Pb/Cd was carried out under controlled laboratory conditions (mineral salt solution with defined species, ionic strength 0.05 mol/l, 25 degrees C and pH 6.0) with initial Pb and Cd concentrations ranging from 0.2 to 2.5 mol/l. The classical Langmuir adsorption isotherm was applied to estimate the equilibrium coefficients of the adsorption of Pb and Cd on the NSCs. Adsorption interference between Pb/Cd and the OCPs on the NSCs indicated that the adsorption of Pb/Cd on the NSCs was influenced by the OCPs, and competitive adsorption between Pb and the OCPs was observed while adsorption of Cd was enhanced by addition of the OCPs. Adsorption data fit the Langmuir isotherm well for the NSCs treated with the OCPs at different equilibrium concentrations. The results showed that the amount of adsorbed Pb decreased by more than 40% while the amount of adsorbed Cd increased by over 60% with an increase in the initial concentrations of the OCPs ranging from 0 to 5.0 microg/l and that adsorption of Pb/Cd on the NSCs was strongly affected by the OCPs. This preliminary study highlights the importance of the OCPs on the NSCs in controlling the transport, fate, biogeochemistry, bioavailability and toxicity of trace metals in aquatic environments.     

建立环境预警监测体系的探讨

要实现环境保护的"三个转变",环境预警监测处在最前沿.如何建立环境预警监测体系,充分发挥各组成部分的功能,成为目前环境监测的中心工作.本文从环境预警监测工作的作用和重要性入手,分析了体系的组成部分:人才、技术能力和监测质量.