生化-物化组合工艺处理城市垃圾渗沥液试验研究

采用厌氧序批式反应器(ASBR) SBR工艺生物处理单元和混凝沉淀 过滤 活性炭吸附深度处理单元对西安江村沟垃圾卫生填埋场渗沥液进行处理研究.结果显示:ASBR投配率14%(HRT=7d),pH=7时,系统运行稳定,COD去除率为45%,而SBR的COD去除率仅为30%.混凝沉淀-过滤-活性炭吸附深度处理后,各单元出水COD、氨氮和色度均呈阶梯式下降,出水COD为177.4mg/L,氨氮为103.5mg/L,色度为40倍.试验表明:AS-BR-脱氨-混凝沉淀、过滤-吸附工艺可实现渗沥液的有效处理.     

膜分离腐殖酸前后晚期渗沥液的活性炭吸附特性研究

对晚期渗沥液及膜分离提取腐殖酸后的透过液进行了活性炭吸附特性研究.结果表明:活性炭对晚期渗沥液和膜透过液中有机物的吸附符合Freundlich吸附等温线,吸附效果良好.活性炭对晚期渗沥液中有机物具有较好的吸附效果,对腐殖酸表现出优先吸附作用,对其中较低分子量的有机物会选择性地吸附;膜透过液中相对较高分子量的富里酸难于被吸附,而分子量较低的富里酸和其他有机物则较易被吸附,TOC和E2去除率分别达到75%和72%,膜透过液的活性炭最佳投加量为8 g/L.     

矿化垃圾处理前后渗沥液组成研究

用不同孔径系列膜对老港填埋场调节池渗沥液进行梯度分离,对分离前后的渗沥液测定了COD、TOC、UV254等参数,并建立了各参数与不同孔径膜的关系。同时运用矿化垃圾反应床进行处理,对处理前后渗沥液的组分变化进行测定。结果表明:渗沥液的绝大部分污染物质集中于可溶性部分,而经矿化垃圾生物反应床处理后渗沥液,分子质量小于1 000 u的溶解性有机物的含量最高,在90%以上,胶体类与不溶性有机物含量较低,在10%左右。     

石灰混凝-纳滤法深度处理垃圾渗沥液

采用石灰混凝法处理垃圾渗沥液生化出水,考察了石灰投加量、混凝剂种类对产水COD、氨氮、pH、色度、硬度的影响,并对石灰混凝前后产水的纳滤通量和出水水质进行对比.结果表明:石灰混凝可以有效降低90％以上的硬度,COD、氨氮、色度去除率为30％～60％.垃圾渗沥液生化出水经混凝后进行纳滤处理可有效提高通量出水中COD、氧氧...     

拉萨市垃圾填埋场渗沥液水质分析与评价

以西藏拉萨市垃圾填埋场渗沥液为研究对象,分别在不同季节对该场垃圾渗沥液原液和经过渗沥液处理站处理后的渗沥液水样的pH、CODCr、BOD5、NH3-N、色度、悬浮物、As、Cr6+、TN、TP、粪大肠杆菌群数等指标进行了分析与评价。结果表明:拉萨市垃圾填埋场渗沥液中CODCr、BOD5、NH3-N、Cr6+、As、TP和TN的平均浓度分别达到2.01×104、4.24×103、726.09、0.28、0.11、16.92、730.33 mg/L,而且季节的变化对拉萨市垃圾填埋场渗沥液水质中CODCr、BOD5、NH3-N、TN的浓度变化影响较大;CODCr、BOD5浓度低于我国初期垃圾填埋场渗沥液水质的平均浓度,高于我国老龄垃圾填埋场渗沥液水质的平均浓度;经过渗沥液处理站处理后排放口水质各污染物浓度能达到GB 16889—2008生活垃圾填埋场污染控制标准中规定的生活垃圾填埋场水污染排放浓度限值,总体出水水质能够满足城市绿化用水水质标准。     

木炭对垃圾渗沥液中COD的吸附性能研究

研究了木炭对垃圾渗沥液中COD的吸附过程,同时应用吸附动力学模型pseudo-first order和pseudosecond order及吸附等温模型Langmuir和Frundlich对吸附数据进行拟合。结果表明,吸附36 h后吸附过程趋于平衡,渗沥液中COD的初始浓度为414、1 164、2 179 mg/L时,COD的去除率分别为89.79%、84.03%、65.91%,单位吸附量分别为9.28、24.45、27.87 mg/g。木炭对COD的吸附符合pseudo-second order动力学模型及Langmuir吸附等温模型,液膜扩散和化学吸附反应是影响吸附速率的主要步骤。生物质炭对渗沥液中COD有较好的去除效果。     

垃圾渗沥液污染水体治理的工艺研究与工程实践

采用混凝沉淀、土工管袋截留、活性炭吸附的工艺对受垃圾渗沥液污染的水体进行处理,现场试验和工程实施中发现:混凝剂的盐基度和加入量对色度脱除率有较大影响;絮凝剂的电性和分子量对色度脱除率、絮体团聚性能有较大影响;活性炭的碘值和类型对COD去除率影响较大;土工管袋在本项目中起到了代替沉淀池的作用。     

电化学氧化老龄垃圾渗沥液研究

通过不同电极电化学氧化垃圾渗沥液处理的对比研究,选择以Ti/Ru-Ir作为电极阳极材料,研究了电流密度、氯离子浓度、初始pH对电化学氧化垃圾渗沥液的影响。结果表明:电流密度为30 mA/cm2,氯离子浓度5 000mg/L,pH在8.09的情况下,电解6 h垃圾渗沥液,氨氮去除率达到100%,COD去除率为50%,UV254去除率为61.09%,垃圾渗沥液BOD/COD从0.14提高到0.22,垃圾渗沥液生化性得到极大提高。经济性分析表明垃圾渗沥液电化学处理6 h后,氨氮去除率达到100%时,单位能耗为0.08 kW.h/g。     

应用UBAF法深度处理垃圾渗沥液的试验研究

北京市某垃圾填埋场渗沥液经二级处理后出水中的CODCr、NH3-N、SS和色度等主要污染物质不能达标排放,在实验室中采用UBAF(升流式曝气生物滤池)小试装置对该出水进行深度处理.结果表明:在进水流速为150cm/s的条件下,出水中CODCr、 NH3-N、SS和色度的去除率可分别达到70%、85%、87%和80%以上,出水水质最终可达标排放.     

基于电化学氧化技术对垃圾渗沥液深度处理的研究

采用了单室电极、平板Ti/PbO2阴极双室电解和气体扩散阴极(GDE)双室电解3种方式对两级矿化垃圾床出水进行了深度处理研究。3种电解方式对垃圾渗沥液都具有很好的脱色效果,而以气体扩散电极为阴极的双室电解,具有最好的TOC去除效果,5 V电解2 h后,阳极液TOC去除率为55%,阴极液TOC去除率为41%,实现了阳极和阴极的双极氧化,显著降低了能耗。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.