浅议液晶LED行业酸性废气系统氮氧化物减排

液晶(LED)显示面板行业在酸处理氮氧化物的问题上一直缺乏有效的技术手段,现有的处理工艺在应对含有硝酸类物质的污染物时,或多或少存在处理后氮氧化物消减不理想的问题。直观看排放时会有黄烟产生,主要是因为处理后氮氧化物(NO、NO_2)浓度高于80mg/m~3所致。文章以北京京东方显示技术有限公司(Beijing BOE Display Technology Co,Ltd.以下简称BOEDT)酸排改造工程为例,介绍说明实现氮氧化物减排和消减总量降低排放浓度的最新工艺。该工程将现有的一段喷淋吸收处理方式改为三段式串联洗涤处理方式,氮氧化物去除率达到95%以上,氮氧化物排放浓度低于60mg/m~3,从根本上消除了黄烟现象,达到了氮氧化物减排目的。     

中小型锅炉采用简易烟气再循环减少氮氧化物污染气体排放

介绍一种从引风机出口烟道上抽取小股低温烟气通入送风机进口管道输入炉内,抑制氮氧化物的生成,烟气ＮＯｘ浓度由２５０ｍｇ／ｍ＾３￣３５０ｍｇ／ｍ＾３降到５０ｍｇ／ｍ＾３￣７０ｍｇ／ｍ＾３。降低ＮＯｘ排放浓度最大达８０％￣８５％,该项技术不影响锅炉运行经济性,投资省,效果明显。在现有中小型锅炉上采用简易烟气再循环系统,实用有效。     

矿山常用的三种质量浓度

作业场所粉尘浓度、呼吸性岩(煤)尘接触浓度及管道粉尘浓度等矿山常用的三种质量浓度及其现行标准是矿山企业安全生产及防尘技术管理的常用指标。该从基本概念出发，以实用为目的，重点介绍三种质量浓度的计算、测试方法及其现行标准。     

乌鲁木齐2000年大气污染预测分析

乌鲁木齐大气污染总趋势日益严重。本文根据多年的大气监测数据,采用灰色系统理论 GM(1,1)模型预测了1989—2000年乌鲁木齐市大气颗粒物,二氧化硫、氮氧化物浓度的变化趋势。结果表明灰色系统模型对城市大气污染物浓度的预测具有一定的实用价值。     

中草药提取物对致病弧菌抑菌活性的筛选

为了寻找高效植物源杀菌剂,实验采用平板扩散法研究了8种中草药醇提物对致鱼病菌的体外抑菌试验。通过双倍试管稀释法,测定了最小抑菌浓度(MIC)和最低杀菌浓度(MBC)。结果显示,这8种中草药醇提物对致病弧菌均有不同程度的抑制作用,其中以臭椿和盐肤木醇提物对所有供试菌均有较高的抑制活性,臭椿醇提物对病菌的MIC均在7.81mg/mL以下,表明中草药杀菌剂具有较高的开发价值和应用前景。     

烧结(球团)工艺过程氮氧化物产生及控制

对某大型钢铁企业三条烧结生产线与一条球团生产线NOx产生情况进行了对比研究,提出了烧结(球团)烟气NOx控制策略。烧结(球团)烟气中的氮氧化物均以NO为主,占NOx总量的比例不低于94%。在温度降低、混合时间延长的特定环境下,高温烟气中的NO能转化为其他含氮气体组分,NOx总量呈下降趋势。球团生产时,因高炉煤气、焦炉煤气含氮而产生的燃料型NOx占烟气氮氧化物排放总量的16.5%,以温度型NOx产生为主;烧结生产工艺中,固体燃料煤或焦末中氮含量高达0.83%~1.26%,烟气中氮氧化物产生以燃料型NOx为主,占烟气中NOx总量的比例不低于80%。烧结(球团)烟气中NOx浓度随烧结机上料量增加呈明显上升趋势。鉴于我国目前仍缺乏成熟的烧结(球团)烟气脱硝末端治理技术与工程应用案例,加强生产过程控制是实现烧结(球团)烟气氮氧化物达标排放的重要举措。     

臭氧浓度迅速降低的原因

美国科学家指出:飞行于地球上空的飞船探测表明,破坏臭氧浓度的化学物质正在北半球迅速增加。科学家们在1992年2月3日的一次报告中指出:一个新的研究卫星最近探测出一种高浓度的氯化物(clo)等化学物质是导致臭氧的保护层遭受破坏的原因,并且这些物质在欧洲和北纬50°的亚洲地区迅速增加。他们认为氯化物(clo)的浓度类似于在南极洲发现的所谓导致“臭氧洞”的物质。大气层之上的臭氧层挡住了来自太阳的高频率有害的紫外线辐射,科学家们认为臭氧的散失会使遭受紫外线辐射的地区增加,首先导致皮肤癌。美国太空大气层研究计划署(NASA)主任米迦     

《地面水质量标准(GB3838—88)》中非离子氨浓度的计算方法

本文分析了《地面水质量标准》(GB3838—88)中非离子及氨查表换算法可能的缺点,介绍了一种仅用计算式可快速、准确计算5—30℃水温,pH=6.0～10.0范围内任意温度、任意pH值时非离子氨百分比、允许总氨浓度,非离子氨浓度的方法,并具体计算与文献值比较,结果表明此计算式是正确和简便实用的。     

氮氧化物控制技术现状与进展

介绍了几种最新的氮氧化物(NOx)控制技术,对主要的两种脱硝技术-选择性非催化还原(SCNR)和选择性催化还原(SCR)技术进行较为详细的讨论,并介绍了低温SCR、双氧水氧化、臭氧氧化脱硝技术的最新研究进展。     

关于我国大气环境质量标准中的氮氧化物标准问题

大气环境质量标准是搞好大气环境质量管理的重要依据。世界各国往往根据自己的国情制定出各自的标准,在大气环境要素方面,除氮氧化物一项外,各国基本上是一致的。就氮氧化物而言,西德制定了包括氮氧化物(NOx)、二氧化氮(NO_2)和一氧化氮(NO)在内的三项质量标准,这是世界上唯一的。而美、苏、日、加拿大等工业发达国象只制定了NO_2的质量标准。除西德以外的一些欧洲国家,如匈、意、波、东德、西班牙等国,有的制定了氮氧化物(NO_X)和二氧化氮(NO_2)两项质量标准,有的只制     

焚烧法处理油泥（砂）试验研究

在对江苏油田原油成分及油泥(砂)等物料组分分析的基础上,采用燃料煤与一定比例的油泥(砂)混合进行高温焚烧,试验研究、筛选出一种可以保证燃烧效率的燃料混合配比,从而对油田储油罐和三相分离器中的油泥(砂)进行处理。结果表明:在燃煤中添加30%的油泥(砂),焚烧工况稳定,好于单用燃煤的情况,除SO2外,CO、NOX和烟尘得到较好的控制。     

天然气脱硫回收工艺的职业病危害及防护措施

天然气中常含有硫化氢、一氧化碳和有机硫等酸性组分,酸性组分的存在会造成金属腐蚀、环境污染并进而危害人体健康等。文章简单介绍了天然气脱硫净化及硫磺回收工艺,重点对天然气生产过程中所产生的硫化氢、甲烷、硫磺、二氧化硫、一氧化碳、氮氧化物、噪声、高温等职业病危害因素进行了识别,分析并介绍了其影响及防护措施。     

THE POTENTIAL FOR REMOTE SENSING OF LOESS SOILS SUSPENDED IN SURFACE WATERS1

ABSTRACT: The potential for detecting the concentration and type of soils suspended in surface water through remote sensing techniques was investigated by studying the spectral reflectance of two types of soils in suspension. In a large tank filled with 7510 liters of water, 20 levels of suspended sediment (soil) concentration (SSC), ranging from 50 to 1000 mg/l were prepared. A high resolution spectroradiometer was used to measure the reflectance at each SSC level. The reflectance spectra of two contrasting soils were distinct in the visible and near infrared (NIR) portions of the electromagnetic spectrum. The wavelength range between 580–690 nm (visible) was found to be optimal for indicating the type of soil, whereas, the wavelength range between 714–880 (NIR) was found to be appropriate for estimating the concentration of sediment suspended in surface waters.     

Trapping efficiencies of cultivated and natural riparian vegetation of northern Laos

In northern Laos, intensification of cultivation on sloping land leads to accelerated erosion processes. Management of riparian land may counteract the negative impacts of higher sediment delivery rates on water quality. This study assessed water and sediment concentration trapping efficiencies of riparian vegetation in northern Laos and the effect of cultivation of riparian land on water quality. Runoff flowing in and out of selected riparian sites was monitored by means of open troughs. In 2005, two native grass, two bamboo, and two banana sites were monitored. In 2006, adjacent to steep banana, bamboo, and native grass sites, three upland rice sites were established and monitored. Water trapping efficiency (WTE) and sediment concentration trapping efficiency (SCTE) were calculated on an event basis; means and 95% confidence intervals (CIs) were estimated with a bootstrapping approach. Confidence intervals were large and overlapping among sites. Seepage conditions severely limited trapping efficiency. Native grass resulted in the highest WTE (95% CI, -0.10 to 0.23), which was not significantly different from zero. Banana resulted in the highest SCTE (95% CI, 0.06-0.40). Bamboo had negative WTE and SCTE. Median outflow runoff from rice sites was nine times the inflow. Median outflow sediment concentration from rice sites was two to five times that of their adjacent sites and two to five times the inflow sediment concentration. Although low-tillage banana plantation may reduce sediment concentration of runoff, cultivation of annual crops in riparian land leads to delivery of turbid runoff into the stream, thus severely affecting stream water quality.     

石油类对小麦生长的影响研究

为了弄清含油土壤中石油类对小麦生长情况的影响,中原油田进行了两年的盆栽小麦实验。实验中采用不同含油浓度,分别对小麦的出苗率、有效分蘖数、株高、穗长、千粒重及品质进行了观察比较。结果表明:土壤中原油含量对小麦的出苗率影响最明显,其它小麦粒中苯并芘及挥发酚残量均低于国家标准。     

A CARLSON-TYPE TROPHIC STATE INDEX FOR NITROGEN IN FLORIDA LAKES1

: A data base consisting of predominantly nitrogen limited Florida lakes from the National Eutrophication Survey (NES) was used to develop a trophic state index based on total nitrogen concentration. This index was compared with Carlson's (1977) index based on total phosphorus concentration, and the lesser of the two values for each lake was averaged with indices based on Secchi disk transparency and chlorophyll a concentration to assess the trophic state of the 40 Florida NES lakes.     

Lateral movement of soil fumigants 1,3-dichloropropene and chloropicrin from treated agricultural fields

The soil fumigants 1,3-dichloropropene (1,3-D) and chloropicrin (CP) are often used for controlling soil-borne plant pathogens and parasitic nematodes before reestablishing new vineyards and orchards. To evaluate crop safety and environmental risks with the replant fumigation, four field experiments were performed over 2 yr to examine 1,3-D and CP lateral movement away from the treated fields. Shank injection with or without a virtually impermeable film (V1F) was used in two vineyard fumigation experiments, and spot drip application without tarp cover was used in two orchard experiments. Results showed that 1,3-D and CP gases moved laterally to 6 m from the treated fields when the fumigants were applied by shank injection. The maximum 1,3-D or CP soil gas concentration at 6 m was approximately 10 ng cm(-3) when the fumigated plot was not cover with a tarp. With VIF, the measured maximum concentration increased to approximately 100 ng cm(-3). In the spot drip application, maximum 1,3-D and CP gas concentrations reached approximately 100 ng cm(-3) but at 1.5 m radial distance from the point of fumigant injection.     

Phosphorus runoff: effect of tillage and soil phosphorus levels

Continued inputs of fertilizer and manure in excess of crop requirements have led to a build-up of soil phosphorus (P) levels and increased P runoff from agricultural soils. The objectives of this study were to determine the effects of two tillage practices (no-till and chisel plow) and a range of soil P levels on the concentration and loads of dissolved reactive phosphorus (DRP), algal-available phosphorus (AAP), and total phosphorus (TP) losses in runoff, and to evaluate the P loss immediately following tillage in the fall, and after six months, in the spring. Rain simulations were conducted on a Typic Argiudoll under a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Elapsed time after tillage (fall vs. spring) was not related to any form of P in runoff. No-till runoff averaged 0.40 mg L(-1) and 0.05 kg ha(-1) DRP and chisel-plow plots averaged 0.24 mg L(-1) and 0.02 kg ha(-1) DRP concentration and loads, respectively. The relationship between DRP and Bray P1 extraction values was approximated by a logistic function (S-shaped curve) for no-till plots and by a linear function for tilled plots. No significant differences were observed between tillage systems for TP and AAP in runoff. Bray P1 soil extraction values and sediment concentration in runoff were significantly related to the concentrations and amounts of AAP and TP in runoff. These results suggest that soil Bray P1 extraction values and runoff sediment concentration are two easily measured variables for adequate prediction of P runoff from agricultural fields.     

Behavior of cinosulfuron in paddy surface waters, sediments, and ground water

Cinosulfuron (3-(4,6-dimethoxy-1,3,5-triazin-2-yl)-1-[2-(2-methoxyethoxy)-phenylsulfonyl]-urea) is a sulfonylurea herbicide used to control a wide range of broadleaf weeds in rice (Oryza sativa L.). A 2-yr field study was conducted in northwest Italy to determine the effect of cinosulfuron on surface and subsoil waters in rice paddies. Cinosulfuron was applied at 70 g a.i. ha(-1) on 35 ha of flooded rice. After the treatment, the change in herbicide concentration over time was studied by analyzing water and sediment samples in a test paddy field (2.16 ha, located in the treated area), water in a spring and a pond (both located near the test paddy), two wells (up- and downhill to the treated area), and two piezometers (along the test paddy levee). To better understand some of the field study results, cinosulfuron degradation was also evaluated in the laboratory in solutions buffered to different pH values. Two weeks after the treatment, the cinosulfuron concentration in the paddy water decreased by about 60%. No cinosulfuron was detected at about 2.5 mo after the treatment. The concentration in the sediment gradually increased after the treatment, reaching the highest value (13.53 microg kg(-1)) 3 wk later. The maximum cinosulfuron content in the spring and pond were 0.91 and 0.29 microg L(-1), respectively, and these were detected 60 to 90 days after treatment (DAT). The water collected in the piezometers reached the highest concentration (0.99 microg L(-1)) 29 DAT. Cinosulfuron was never detected in the wells. In the degradation study at different pH values, cinosulfuron degraded rapidly at low pH values.     

Direct and indirect hydrological controls on E. coli concentration and loading in midwestern streams

This study investigates hydrological controls on E. coli concentration and loading in two artificially drained agricultural watersheds (58 and 23 km(2)) of the U.S. Midwest. Stream E. coli concentrations are significantly (p < 0.02) lower at base flow than high flow; however, E. coli load is significantly higher at high flow than at low flow (p < 0.001). Although E. coli concentrations are not significantly higher (p = 0.253) in summer/fall (3269 MPN/100 mL) than in the winter/spring (2411 MPN/100 mL), E. coli load is significantly higher (p < 0.05) in winter/spring (346 MPN/day) than in summer/fall season (75 MPN/day). Correlation analysis indicates that discharge and precipitation are the best indicators of E. coli concentration and 7-d antecedent precipitation (7dP), the best indicator of E. coli loading in the watersheds studied regardless of flow conditions and location. However, E. coli concentration and loading best correlate to 7dP and turbidity at base flow. A spatial dependency is also observed at base flow with E. coli concentration and load correlating better to 7dP in the headwaters and to turbidity in the lower reaches of the watersheds studied. For high flow conditions, E. coli concentration and loading are poorly correlated to most variables, except stream water temperature and 7-d antecedent discharge. These results are consistent with those reported in the literature and suggest that, at least during base flow conditions, turbidity and 7dP may be usable in artificially drained landscapes of the Midwest to identify potential hot spots of E. coli contamination.