活性碳纤维吸附处理对硝基苯酚生产废水

采用活性碳纤维(ACF)吸附处理对硝基苯酚(PNP)生产废水,考察了动态吸附和脱附过程.实验结果表明,在298 K、pH 4时,最佳进水流量为0.25 L/h,ACF的有效吸附量为439.3 mg/g,PNP去除率大于99.95%,TOC去除率大于99.5%,脱附率大于99.5%,ACF的吸附--脱附性能稳定.ACF吸附和电解相结合的工艺能有效去除废水中的有害物质,回收利用PNP和氯化钠,实现了PNP的清洁生产.     

锅炉鼓引风机的变频节能改造

锅炉鼓风机及引风机靠风机入口的风门挡板来调节风量,效率低,造成能源浪费.通过对离心风机的变频节能原理的分析,提出具体变频改造方案,并对改造后的效果进行对比,说明采用变频调速控制方式将大大提高风机设备的运行效率,改善风机工况,节能降耗,降低生产成本,直接和间接经济效益十分明显.     

桥梁施工的安全管理

施工安全管理工作是工程项目管理必不可少的重要组成部分,贯穿于施工的全过程,是贯彻“以人为本”方针的重要措施。桥梁施工必须认真贯彻“安全第一,预防为主”的方针,严格遵守一切规章制度,严格管理,严守职责,切实抓好安全生产工作,为工程施工项目创造更多的经济效益和社会效益。     

CN-测定中显色剂配制方法的选择与保存时间

对2种氰化物显色剂配制方法进行了对比,发现用无水乙醇配制的显色剂具有方便,经济,实用,无毒且显色剂保存期长等优势。     

塔山水库蓝藻暴发的成因及控制

简述了塔山水库蓝藻暴发的过程及成因。指出 ,由于水库的营养物质增多、水质恶化 ,在不利的水文、气象 (高温、光照充足、微风 )等条件下 ,导致蓝藻暴发。提出了相应的控制对策     

江苏省12大湖泊水环境现状与污染控制建议

江苏面积大于50km^2的12个湖泊的水质恶化、面积减少、富营养化、湖泊生态系统退化与湖泊受TP、TN的污染和围湖造田等有关。经济快速发展,第二产业结构偏重,排放污染的总量超过湖泊承载力,湖泊底泥释放N、P及入糊河流携带污染物为造成湖泊环境问题的根本原因。建议调整产业结构,执行严格的排放标准,围绕重点区域、重点行业、重点企业和重点污染源治理,由控制COD为主转为控制COD和N、P并重,引水调控水质,建立湖泊资源数据库和生态系统信息网络,开展湖泊污染物来源分析和富营养化机理研究,开展跨界区域统筹对湖泊综合治理。     

新疆主要城市集中式饮用水源地水质评价

2007年新疆环保系统的调查和评价结果表明,新疆16个主要城市的31个现役集中式饮用水源地总供水量为4.47×10^8m^3,担负着供应420万常住城市人口的生活饮用水、部分工业用水和城市生态用水的责任;城市饮用水源地总体水质良好,水质达标比例为83.9%,不同地区、不同水源类型间存在差异;由于受原生土壤地质条件和人类活动的影响,目前有5个集中式饮用水源地超过国家规定的水质标准,而且部分饮用水源地中有机污染物有多项检出;受水源保护区划工作滞后、监管力度不够等因素影响,部分城市饮用水源地存在一定的环境安全隐患。     

The ageing effect on the bioaccessibility and fractionation of arsenic in soils from China

Ingestion of contaminated soil has been recognized as an important exposure pathway of arsenic for humans, especially for children through outdoor hand-to-mouth activities. An improved sequential extraction procedure was employed in an attempt to reveal the relationship between bioaccessibility and fractionation of As in five soils from China. Arsenic bioaccessibility in acidic ( approximately pH 4.5) soils reached approximately stable levels after a sharp decline within one week of ageing. In contrast, As bioaccessibility in higher pH (>6.0) soils was found to be significantly higher and took two weeks of ageing to reach stable levels. The artificially added As was more labile than indigenous As. The main proportions of added As were found in the specifically sorbed and amorphous and poorly-crystalline hydrous Fe/Al oxide-bound fractions. Correlation analysis shows that the non-specifically and specifically sorbed As are likely to constitute the main proportion of bioaccessible soil As. The soil content of amorphous and crystalline Fe/Al oxides and soil pH appear to be the key factors controlling, not only the time needed to reach a steady state, but also the magnitude of the bioaccessibility of As added to the soils.     

Mathematical analysis of the whole core injection method accuracy for measuring phenanthrene biodegradation rates in undisturbed marine sediments

Rates of 14C-phenanthrene mineralization in contaminated, undisturbed marine sediments were measured using the whole core injection method to assess microbial natural attenuation activity as a function of sediment depth. Submerged sediments were sampled from Eagle Harbor, a marine superfund site in Puget Sound. Experiments show significant biodegradation activities (0.0012-0.0036 day(-1)) in the sediment horizons from 0 to 10 cm. The purpose and scope of this paper is to evaluate the range of experimental conditions giving valid results; a mathematical simulation described competing contaminant 14C-phenanthrene diffusion and simultaneous biodegradation (Monod kinetics), both retarded by sorption. The effect of aging was examined with two sorption models in presumed pseudo-homogenous sediments having effective properties. The simulation predictions provide quantitative guidelines for the successful use of the whole core injection method. (1) The effective Monod constant KS' in sediment is increased by a large partition coefficient KP between sediment and water and makes the apparent 14C-phenanthrene biodegradation approach first-order kinetics. (2) When KS'>1 mg(-1) l(-1), the measured 14C-phenanthrene biodegradation extent is biased by inadequately distributed injected tracer only when less than 7% of the sediment horizon is initially probed and mixed with injected tracer. (3) A short incubation time (<20 days) is necessary when a mobile indicator, e.g., gaseous 14CO2, is used. For longer incubation times, predictions show that a 14CO2 indicator diffuses to adjacent horizons, thus smearing the depth profile of biodegradation. (4) This method employing a radiolabeled tracer provides accurate biodegradation rates for freshly contaminated sediments, and represents an upper limit to the natural phenanthrene biodegradation extents if the contaminant is aged over 50 days.     

Challenges in quantifying biosphere-atmosphere exchange of nitrogen species

Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols.