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151.
通过介绍厌氧处理技术在城市污水处理中的现状及研究焦点,论述了以微生物固定化和提高污泥与污水混合效率为基础的一系列高速厌氧反应器的特点,分别阐述了升流式厌氧污泥床、折流式厌氧反应器、内循环厌氧反应器及颗粒污泥膨胀床反应器的研究进展,提出高效率的厌氧处理系统应满足的条件,并与好氧处理技术作了对比,综述了新型反应器的研制及其组合工艺的应用在废水处理领域所发挥的重要作用.  相似文献   
152.
福建古生界至中生界部分地层古地磁研究认为,华南地块的主体部分首先于中奥陶世时期即已拼合,作为一个整体由南纬23.8°向北移动,二叠纪之后越过赤道,继续北移,直至侏罗纪末到达北纬19.6°的位置.而华南地块同扬子地块的拼合是在加里东末期开始的,至少可以认为是在早石炭纪之前两地块就靠近了。这一时期,华南地块和扬子地块的地质构造运动十分活跃.  相似文献   
153.
Method development for determination of fluroxypyr in water   总被引:2,自引:0,他引:2  
Improved methods for extraction and clean up of fluroxypyr residue in water have been established. Two methods of fluroxypyr extraction were used, namely, Direct Measurement of fluroxypyr and Concentration of fluroxypyr onto A Solid Phase Extraction (SPE) Adsorbent, followed by elution with solvent before determination of fluroxypyr. The recovery for Direct Measurement of fluroxypyr in water containing 8-100 microg L(-1), ranged from 86 to 110% with relative standard deviation of 0.7 to 2.15%. For the second method, three types of SPE were used, viz. C18, C18 end-capped and polyvinyl dibenzene (ISOLUTE ENV+). The procedure involved concentrating the analyte from fluroxypyr-spiked water at pH 3, followed by elution of the analyte with 4 mL of acentonitrile. The recovery of fluroxypyr from the spiked sample at 1 to 50 microg L(-1) after eluting through either C18 or C18 end-capped ranged from 40-64% (with relative standard deviation of 0.7 to 2.15) and 41-65% (with standard deviation of 1.52 to 11.9). The use of ISOLUTE ENV+, gave better results than the C18, C18 end-capped or the Direct Measurement Methods. The recovery and standard deviation of fluroxypyr from spiked water using ISOLUTE ENV+ ranged from 91-102% and 2.5 to 5.3, respectively.  相似文献   
154.
This paper reviews the effects and control methods for particulate matter (PM) in animal indoor environments. PM in animal indoor environments represents a particular threat to the health of countless animals and millions of workers around the world. Because air in animal facilities has a higher portion of biological content than does air in other environments, the adverse health impact is much greater than it is for the same amount of PM in other environments. Source control, ventilation, and internal air cleaning can reduce PM concentration in animal indoor environments. Source control is typically the most economical method for PM control. Ventilation is the most widely applied technology, although uncertainties remain as to its effectiveness for PM control. Most internal air cleaners require frequent maintenance because of the high concentration and stickiness of PM in animal environments. Filtration is the most well-studied and widely used technology for internal air cleaning because of its low capital cost and high efficiency. Several trials using electrostatic precipitators have shown efficiencies of approximately 50% in removing PM concentration, but improvements are needed before they can be used widely. No report using wet collectors or centrifugals as internal air cleaners has been found.  相似文献   
155.
Progress in developing an ANN model for air pollution index forecast   总被引:3,自引:0,他引:3  
An air pollution index (API) reporting system is introduced to selected cities of China for public communication on air quality data. Shanghai is the first city in China providing daily average API reports and forecasts. This paper describes the development of an artificial neural network (ANN) model for the API forecasting in Shanghai. It is a multiple layer perceptron (MLP) network, with meteorological forecasting data as the main input, to output the next day average API values. However, the initial version of the MLP model did not work well. To improve the model, a series of tests were conducted with respect to the training method and structure optimization. Based on the test results, the training algorithm was modified and a new model was built. The new model is now being used in Shanghai for API forecasting. Its performance is shown reasonably well in comparison with observation. The application of the old model was only weakly correlated with observation. In 1-year application, the correlation coefficients were 0.2314, 0.1022 and 0.1710 for TSP, SO2 and NOx, respectively. But for the new model, for over 8 months application, the correlation coefficients are raised to 0.6056, 0.6993 and 0.6300 for PM10, SO2, and NO2. Further, the new algorithm does not rely on manpower intervention so that it is now being applied in several other Chinese cities with quite different meteorological conditions. The structure of the model and the application results are presented in this paper and also the problems to be further studied.  相似文献   
156.
Chapter three: methodology of exposure modeling   总被引:1,自引:0,他引:1  
In this chapter, the concept of exposure assessment and its evolution is introduced, and evaluated by critically appraising the pertinent literature as it applies to exposures to Particulate Matter (PM). Exposure measurement or estimation methodologies and models are reviewed. Three exposure/measurement methodologies are assessed. Estimation methods focus on source evaluation and attribution, sources include those outdoors and indoors as well as in occupational and in-transit environments. Fate and transport models and their inputs are addressed to estimate concentrations outdoors and indoors; source attribution techniques help focus on the contributing sources. Activity pattern techniques are also reviewed and their use in exposure models to estimate inhalation exposure to PM is presented. Deterministic, regression and other stochastic models of exposure to PM are reviewed and evaluated. Strengths, limitations, assumptions and affirmations of the use of exposure assessment as an integral component of risk assessment and risk management are discussed in the conclusions and discussions section of this work.  相似文献   
157.
利用GCMS定性分析漂白废水主要发色物质的种类,对黄孢原毛平革菌在抑制条件下的生长与脱色作用进行试验研究,结果表明,废水中各类高分子量有机污染物是形成色度的主要来源,此类物质在菌对数生长阶段被大量降解。  相似文献   
158.
分析了焦作某电厂堆灰场附近浅层地下水中Cr6+ 的形成原因。根据该区水文地质背景 ,提出在地下污染水羽的下游建可渗透反应墙的漏斗 -通道系统 ,用对Cr6+ 有很高去除效率的风化煤作为反应材料 ,使污染水羽流经此系统时有效去除地下水中的Cr6+ ,达到净化的目的  相似文献   
159.
宋波  杨丙杰  李毅  刘欣  于东兴 《火灾科学》2017,26(4):232-238
为研究戊类仓库的火灾危险性,在对比分析国内外仓库火灾危险性划分方式的基础上,通过构建典型戊类仓库的火灾试验模型,开展了不同情况下的火灾燃烧特性对比试验。研究发现,戊类仓库的外包装材料质量及是否采用木托盘承托等显著影响其火灾危险性,在有木托盘存在的情况下,其火灾规模、火灾增长速率以及对相邻货架的影响均较大,尤其当储存物品自身外包装材料的比重较轻时,其影响更为明显,建议对于采用木托盘承托的戊类仓库均应设置自动喷水灭火系统进行保护。另外,建议仓库在火灾危险性分类时,将木托盘的质量与物品自身的外包装质量之和记为物品的外包装质量。  相似文献   
160.
探讨了化学氧化法、微生物抑制法和pH值调节法对广州某景观水体恶臭的去除效果。结果表明:采用pH调节法可以有效抑制水体发臭,使水体臭强度大幅降低,除臭效果最佳的pH值为8.6~9.5。运用该除臭方法进行工程应用,结果表明该方法能够在短期内迅速降低水体臭强度,除臭效果显著。  相似文献   
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