垃圾焚烧烟气脱硝工艺选择及案例分析

针对垃圾焚烧厂烟气的脱硝技术,分别介绍了各种脱硝技术及其组合脱硝工艺的工艺流程、经济性以及工艺特点。对SNCR+SCR与SNCR+PNCR的NOx超低排放组合工艺分别在浙江省某生活垃圾焚烧项目与广东省某垃圾焚烧项目的运行情况进行分析,总结SNCR+SCR与SNCR+PNCR这2种工艺在工程应用中的系统稳定性、经济性、运行过程存在的问题、工艺需改进的地方及方法。     

SCR系统催化剂研究现状及其在生活垃圾焚烧中的应用

总结分析国内外选择性催化还原反应(selective catalytic reduction,SCR)催化剂的研究现状,从载体、活性成分、制作方法、煅烧温度等方面,对其催化剂的特点及优缺点进行概括性描述,并结合工程实例对垃圾焚烧厂脱硝系统进一步描述,同时针对生活垃圾焚烧电厂的烟气工艺特性分析催化剂的应用难点,提出相应的低温催化剂制备方案,以期能对国内垃圾焚烧厂催化剂的选择有一定的参考意义。     

烟气再循环脱硝技术在生活垃圾焚烧发电厂的应用

根据垃圾焚烧的特点,概述了生活垃圾焚烧发电厂烟气再循环技术的脱硝原理、工艺特点及主要影响因素,并结合生活垃圾焚烧厂烟气再循环技术的应用案例,通过烟气再循环的实际应用性能评价,探讨了烟气再循环比例与氮氧化物浓度的相关性。同时,通过设计方案及过程控制的对比分析,解析了烟气再循环技术的设计原则,为垃圾焚烧烟气再循环技术的设计及应用优化提供依据。     

生活垃圾焚烧厂SNCR脱硝系统的自动控制

为满足垃圾焚烧后烟气中氮氧化物的排放要求,使生活垃圾焚烧厂SNCR脱硝系统安全稳定地运行,提出了该系统的控制原则和自动控制措施:通过喷枪控制回路控制还原剂溶液尽可能在最佳反应温度窗口与烟气充分混合,提高脱硝效率,降低氨的逃逸量;通过烟气中氮氧化物和氨含量控制回路使氮氧化物排放和氨逃逸达到设计要求。     

城市生活垃圾焚烧电厂烟气净化工艺选择

以深圳市南山垃圾焚烧电厂为实例，介绍了深圳市能源环保有限公司引进的比利时西格斯垃圾焚烧烟气净化技术，并对烟气净化设备进行了比较。     

光大环保能源（苏州）有限公司烟气净化系统的提标改造

介绍了光大环保能源（苏州）有限公司的概况,对比该公司烟气净化系统改造前后烟气各项指标的排放浓度,结果表明：采用SNCR脱硝＋（半干法＋干法）脱酸＋活性炭＋袋式除尘器的组合工艺,净化后的生活垃圾焚烧烟气各项指标达到欧盟2000标准。     

垃圾焚烧炉NOx生成特性和SNCR脱硝性能分析

以某城市生活垃圾焚烧厂为研究对象,对该生活垃圾焚烧炉烟气中NO_x生成规律和SNCR脱硝性能进行了分析研究。结果表明:在炉膛温度943～1 174℃,氧浓度5%～7%条件下,NO_x原始浓度在180～350 mg/m~3范围内波动,与炉内氧浓度和温度变化呈现正相关;温度对SNCR脱硝效率有重要影响,SNCR反应区域温度过高是其脱硝效率较低的主要原因。根据研究结果,对焚烧炉内SNCR还原剂喷枪位置进行了改进,使SNCR脱硝反应位于850～1 000℃的合适温度区间内,从而显著提升其脱硝效率。     

城市生活垃圾焚烧处理工艺选择的经济性评价

通过对城市生活垃圾焚烧处理各工艺环节进行具体分析,结果表明:垃圾焚烧系统宜采用机械分选预处理技术、热电联产的能源利用方式、半干法+烟气催化+布袋除尘的烟气处理技术及飞灰固化处理技术相结合。在补贴为140元/t的条件下,从项目投产年算起,流化床、炉排炉和气化熔融技术投资回收期分别为4、5、9 a,等离子体气化焚烧技术在运行年限中不能收回投资。若要推行气化熔融焚烧技术和等离子体气化焚烧技术,一方面可提高这2种技术的垃圾处理补贴,另一方面也可将其环境效益考虑进技术的综合效益。     

生活垃圾焚烧发电厂二恶英控制研究与实践

分析了现代垃圾焚烧厂二恶英的产生原理,从全厂角度提出控制烟气中二恶英含量的方法,即通过采取入炉前预处理、3T+E分解(燃烧温度不低于850℃、气体的停留时间不小于2 s、湍流强化燃烧、控制氧量)、炉外低温合成控制(控制二恶英的再生区间、防止受热面积灰)和末端排放控制(活性炭吸附、SCR)等方式,减少二恶英的产生,实现焚烧的二恶英控制。     

反硝化法垃圾生物干化及烟气脱硝的试验分析

对生活垃圾添加反硝化菌并通入降温后的垃圾焚烧烟气,利用垃圾中的有机质作为电子供体进行反硝化试验。工程试验结果表明,垃圾干化后含水率由原来的60%降低至25%;NOx最高排放浓度是222 mg/m3,优于GB 13271—2014。利用生活垃圾的生物反硝化过程进行垃圾干化及烟气脱硝是一种"以废治废"的环保处理方式。     

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.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

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.