PAC/BPAC-UF对二级出水中有机物去除及膜污染情况对比

目前对溶解性污染物去除效能较低和膜污染严重的问题是超滤(Ultrafiltration,UF)技术的瓶颈,为了改善城市污水处理厂二级出水水质和UF技术的运行稳定性,利用粉末活性炭(Powdered Activated Carbon,PAC)-UF和生物粉末活性炭(Biological Powdered Activated Carbon,BPAC)-UF 2种组合工艺对污水处理厂二级出水进行深度处理。通过DOC、三维荧光、膜通量变化、膜阻力分布及微生物群落结构分布的分析方法,对比研究2种组合工艺对有机物的去除效果,考察不同投加量下PAC和BPAC对膜污染的缓解程度。结果表明,在最佳投加量下2种组合工艺对有机物的去除效果均优于直接UF,膜污染得到有效缓解。具体而言,PAC-UF和BPAC-UF对溶解性有机物的去除效果相差不大,PAC-UF略优于BPAC-UF;对于蛋白质类、腐殖酸类和微生物副产物类有机物,BPAC-UF较PAC-UF的处理效果更优; BPAC-UF较PAC-UF对缓解膜比通量下降和膜污染阻力增长有更好的效能。由于BPAC上微生物的吸附和生物降解作用,BPAC-UF工艺经济适用性较好,BPAC-UF可以作为一种有效的再生水深度处理方法。     

制浆废水混凝-生物-混凝组合工艺有机物去除途径研究

以某造纸厂制浆废水处理工程(3万m3/d)为研究对象,利用红外光谱、三维荧光光谱、相对分子质量切割等方法,探究制浆废水混凝-生物-混凝组合处理工艺有机物的去除机理。结果表明:组合处理工艺COD、色度总去除率分别为94.4%、95.5%;一级混凝、生物处理、二级混凝工艺单元对COD去除的分担率分别为44.2%、37.5%、12.7%,对色度去除的分担率分别为21.6%、31.4%、42.5%。一级混凝单元主要去除MW30 k Da的大分子有机物,以类富里酸、部分芳环及芳香族化合物等难降解有机物为主;生物处理单元主要降解MW10 k Da的有机物,主要有芳香酸酯、类蛋白质物,其中部分有机物转化为MW1 k Da的小分子有机物;二级混凝进一步去除MW30 k Da的大分子有机物,主要是类黑精物、木质素及其衍生物、芳香族化合物等。     

组合芬顿工艺处理垃圾渗滤液纳滤浓缩液的试验研究

利用芬顿和光-芬顿工艺降解垃圾渗滤液纳滤浓缩液中的难降解有机物。起始pH值5.0及较低H_2O_2/Fe~(2+)投加量时,芬顿法的氧化-絮凝作用可以去除70%以上的COD。采用芬顿氧化-絮凝和光-芬顿组合工艺处理不同浓度纳滤浓缩液时,H_2O_2/Fe~(2+)投加量为35 m M/8 m M和90 m M/10 m M时均可实现90%的COD和TOC去除率;组合工艺出水COD为112~160 mg/L,BOD/COD为0.35~0.43。纳滤浓缩液中检出的13种多环芳烃经过组合工艺处理后的总去除率均约在90%。     

负载TiO2颗粒活性炭去除微囊藻毒素- LR的动力学

以活性炭为载体,采用溶胶凝胶法制备负载型的催化剂(TiO2/GAC),进行了有无紫外光降解和有无活性炭条件下的微囊藻毒素- LR( MCLR)降解试验.结果显示,在紫外光照射下,MCLR不会自身降解,且紫外光照对活性炭吸附性能无明显影响.此外,通过负载型催化剂对不同初始质量浓度的MCLR溶液的吸附和光催化降解试验,进行了Lagergreen准二级模型和颗粒内部扩散模型拟合催化剂的吸附去除动力学研究,应用Langmuir- Hinshelwood和Freundlich-Hinshelwood模型拟合光催化降解过程.结果表明,Lagergren准二级模型和Langmuir- Hinshdwood模型均能较好地描述TiO2/GAC对MCLR的吸附、光降解过程,Langmuir-H inshelwood模型中吸附平衡常数Kt值基本保持不变,约(0.057 0±0.0008)L/μg,降解速率常数k值随着初始质量浓度的增加有所下降.     

臭氧氧化法深度处理养猪废水研究

采用臭氧氧化法深度处理经生化工艺处理的养猪废水,探讨反应时间、臭氧投加速率和p H值对COD、色度和UV254去除效果的影响,并采用紫外可见光谱和三维荧光光谱(3DEEM)分析了臭氧氧化前后养猪废水中溶解性有机物(DOM)的变化特征。结果表明,当臭氧投加速率为1.13g/h、反应温度为20℃、p H值为7.2时,反应40 min后养猪废水的COD、色度和UV254去除率分别约为50%、95%和75%。生化处理后的养猪废水主要含有可见腐殖质、紫外腐殖质和微生物代谢产物,臭氧氧化后微生物代谢产物的荧光峰基本消失,可见腐殖质和紫外腐殖质特征荧光峰荧光强度与原水相比也显著降低。研究表明,臭氧对养猪废水中难降解有机物的降解作用非常明显。     

新型电滤床预处理焦化废水研究

采用新型电滤床工艺在自制电化学装置中对焦化废水进行了预处理试验。该工艺将传统铁炭床改造为阳极滤床,多层不锈钢网电极作为阴极,外接直流电源。考察了COD的去除效果及电压、曝气量等因素的影响,并分析了原因。结果表明,在常温、p H=6.4、电压6V,反应时间300 min的条件下,COD去除率可达78%,出水COD为1 220 mg/L。对废水进行了紫外-可见光谱和GC/MS分析。结果表明,废水中存在31种有机物,多为酚类和含氮杂环,处理后68%的物质被降解,包括62%的酚类和91%的含氮杂环有机物。6种新物质主要为脂肪酸、酮类,易于生物降解。可以推断,电滤床法提高了废水的生物可降解性,具有处理焦化废水的应用潜力。     

难降解有机物的生物污泥吸附

综述了各种生物污泥包括活性污泥、厌氧污泥、膜污泥、干污泥、不同方法失活的污泥等对50种难降解有机物的吸附结果.并对生物污泥吸附过程中适用的吸附等温线进行了总结.由于不同来源的生物污泥特性不同,研究者得到的吸附容量和平衡时间的结果相差较大,甚至同类污泥对同种难降解有机物的吸附结果也相差较大.对难降解有机物的生物污泥吸附,目前提出的适用的吸附等温方程式主要有6种,综述的70个研究结果中有81%属于Freundlich模型.23%既符合Langmuir模型又符合Freundlich模型.但大多数的研究仅停留在用模型对实验数据进行拟合以判断吸附类型,并未做深入讨论.同时综述了pH值、吸附质初始质量浓度、二价阳离子、离子强度、微生物有无活性等因素对污泥吸附的影响.各研究者实验的pH范围不同,得出了不同的结论.高的初始浓度会在溶液和生物污泥之间形成大的浓度差,加快吸附的发生和增加生物污泥的吸附鼍;Ca2 等二价阳离子的存在使生物污泥的吸附性能增强,离子强度的影响效果与Ca2 等二价阳离子类似;生物污泥灭活后,污泥表面特性也随之改变,其吸附性能和吸附量也发生变化,但由于生物污泥种类和失活方法不同,各研究者得出了不同的结果.     

活性炭对酚醛类化工废水深度处理的动态吸附性能研究

为活性炭应用于酚醛类化工废水深度处理，研究了活性炭对此类废水中有机物的动态吸附性能以及氮的去除。通过动态吸附试验，选出吸附效果最佳的活性炭，研究其对废水中有机物的等温吸附和动力学，并利用比表面积(BET)测试法和傅里叶红外光谱(FTIR)表征技术分析活性炭表面特征，同时探讨不同因素对吸附的影响，再以床厚服务时间(Bed-Depth-Service Time, BDST)模型对动态试验数据进行线性拟合分析。结果表明：椰壳炭吸附效果最好，朗格缪尔(Langmuir)吸附等温线模型和拟二级动力学模型可以较好地描述其动态吸附行为；吸附过程中粒子内扩散并不是唯一的限速步骤，有机物的吸附主要发生在边界层扩散阶段；根据椰壳炭孔状结构的变化说明吸附主要发生在微孔区；—OH、—COOH、■等官能团能与有机物相互反应，主要涉及氢键、π-π相互作用、静电引力；含氮化合物会与有机物产生竞争吸附，影响其吸附量；BDST模型不仅可以有效描述吸附床高度与穿透时间之间的关系，而且能够准确地预测新的操作条件下的有机物穿透时间，误差均小于5%。     

高含沙体系中影响硝基氯苯迁移转化因素的研究

通过静态吸附实验,研究了去除腐殖质的黄河泥沙对硝基氯苯的吸附规律及机理.实验结果表明,灼烧后的泥沙对硝基氯苯的吸附量随着平衡质量浓度的增加而增高,随粒径的减少而降低.含沙量100 g/L条件下,泥沙中的矿物成分的吸附占总吸附量的71%～82%;腐殖质吸附量占总吸附量的18%～29%.灼烧后的泥沙对硝基氯苯的吸附量随pH值变化较大,pH在6.66左右时吸附量最高.金属离子的存在使吸附量增加,不同金属离子的存在引起吸附量变化的程度不同.     

臭氧和高锰酸钾处理微污染水的比较研究

采用静态试验,分别研究了臭氧、高锰酸钾投加量与高锰酸盐指数、浊度、色度去除的关系.试验结果表明,对于低温微污染水源水,臭氧、高锰酸钾预氧化加常规处理能有效地去除有机物.臭氧预投加量为2 mg/L时混凝后高锰酸盐指数、浊度和色度都有较好的去除效果,混凝后去除率分别为24.6%、96.8%和83.3%;高锰酸钾投加量在0.6 mg/L时混凝后高锰酸盐指数去除率为23.6%.但高锰酸钾会引起水中色度升高和锰离子浓度增加.     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.     

HAZOP结合What-if方法在某延迟焦化装置除焦中的应用

为克服传统危险与可操作性（HAZOP）定性分析方法在复杂操作、间歇作业等过程中使用的局限性,提出在传统HAZOP定性分析方法的基础上结合What-if（故障假设）方法,对人的不安全行为和操作规程不完备所导致的风险后果分析作出补充。详细说明其技术原理、工作流程等使用细节,系统阐述该方法与传统HAZOP定性分析方法的区别,并在某延迟焦化装置的除焦操作的风险分析中应用。经分析,识别出在“给水-泡焦”节点,有“操作规程错误”场景2项,“操作规程不具体”场景1项,不存在“操作人员未按操作规程执行”场景。研究结果表明:本文方法有效且具有较好效果,可以广泛应用于操作规程/作业指导书审查、作业过程隐患排查等方面,帮助企业开展操作层面的风险识别与管理,提升企业的生产安全水平。     

潞安矿区煤层渗透率的各向异性特征实验研究

为了研究原位煤体渗透性的各向异性特征,以山西潞安常村矿3号煤层圆柱试样为对象,利用TCQT-Ⅲ型低渗煤层气相驱替增产试验装置,对煤样进行加载,并以氮气注入压力2.0 MPa的条件下,分析垂直层理和平行层理2个方向的煤体变形和渗透率变化特征。实验结果表明:煤样在加载过程中,平行和垂直层理煤样渗透率均随着有效应力的增大而减小,平行层理方向的渗透率始终大于垂直层理方向,应力加载初期渗透率急剧下降,最后逐渐趋于平缓;径向应变的增加量与渗透率呈正相关性,且平行层理相关性大于垂直层理;沿平行层理方向的裂隙度大于沿垂直层理方向,沿垂直层理方向的应变量大于沿平行层理方向;应变增加量均随有效应力的增加而逐渐减小。研究结果可为煤层井网布置及优化提供参考。     

Nighttime pedestrian fatalities: A comprehensive examination of infrastructure,user, vehicle,and situational factors

Introduction: Pedestrian fatalities in the United States increased 45.5% between 2009 and 2017. More than 85% of those additional pedestrian fatalities occurred at night. Method: We examine Fatality Analysis Reporting System (FARS) data for fatal pedestrian crashes that occurred in the dark between 2002 and 2017. Within-variable and before/after examinations of crashes in terms of infrastructure, user, vehicle, and situational characteristics are performed with one-way analysis of variance (ANOVA) and two-sample t-tests. We model changes in crash characteristic proportions between 2002–2009 and 2010–2017 using linear regressions and test for autocorrelation with Breusch-Godfrey tests. Results: The increase in fatal nighttime pedestrian crashes is most strongly correlated with infrastructure factors: non-intersection unmarked locations (saw 80.8% of additional fatalities); 40–45 mph roads (54.6%); five-lane roads (40.7%); urban (99.7%); and arterials (81.1%). In addition, SUVs were involved in 39.7% of additional fatalities, overrepresenting their share of the fleet. Increased pedestrian alcohol and drug involvement warrant further investigation. The age of pedestrians killed increased more (18.1%) than the national average (3.2%). Conclusions: By identifying factors related to the increase in nighttime pedestrian fatalities, this work constitutes a vital first step in making our streets safer for pedestrians. Practical Applications: More research is needed to understand the efficacy of different solutions, but this paper provides guidance for such future research. Engineering solutions such as road diets or traffic calming may be used to improve identified infrastructure issues by reducing vehicle speeds and road widths. Rethinking vehicle design, especially high front profiles, may improve vehicle issues. However, the problems giving rise to these pedestrian fatalities are likely a result of not only engineering issues but also interrelated social and political factors. Solutions may be correspondingly comprehensive, employing non-linear, systems-based approaches such as Safe Systems.     

Footedness and Mounting—Short Review and Two Case Studies

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement at different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and nondominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).     

AHP与GA-SVM耦合模型在滑坡预警中的应用*

为了减少滑坡造成的损失,提高滑坡预测的准确性,通过搭建灾害模拟平台获得滑坡的实验数据,在获得多组模拟实验数据后,分析各变量的特性。首先,通过层次分析(Analytic Hierarchy Process,AHP)算法,对滑坡进行危险度划分;然后,通过支持向量机(Support Vector Machine,SVM)建立模型,遗传算法(Genetic Algorithm,GA)再优化SVM参数,提出1种层次分析法与GA-SVM相耦合的模型。研究结果表明:AHP方法划分后的数据,通过GA与SVM结合建立的模型精度较好,实验预测结果与实际结果较为吻合,与单一SVM相比,精度更高,结果更好,更加适用于多变量的复杂非线性滑坡预警。     

Debunking the false dichotomy of leadership idealism and pragmatism: Critical evaluation and support of newer genre leadership theories

Leadership theories have shifted over the last few decades from a focus on managerial functions and economic leader–follower exchanges toward greater focus on the interpersonal dynamics occurring within the leadership process. Theories such as transformational, ethical, authentic, and other “newer genre” theories were created to address neglected topics such as leader vision and inspirational messages, transparency, emotional effects, morality, individualized attention, and intellectual stimulation. Critiques of these theories, however, have been raised. In this paper, we address five of those critiques and argue for the validity and practical effectiveness of the new genre theories. Further, we describe how newer genre leadership research should be viewed as a performative epistemology, entailing a process of co‐creation involving scholars and practitioners. Finally, from this view, we provide general ideas for leader development. Copyright © 2014 John Wiley & Sons, Ltd.     

Occupational Safety and Health in Finland

In Finland, occupational safety is the responsibility of the employer, while the occupational safety and health laws are enforced by the Labour Inspection Service, an organization of the state. The Labour Inspection is divided in 11 administrative districts, and it employs 360 professionals. They are mandated to carry out site visits without prearranged appointments to inspect safe work situations, working hours, construction safety, or any aspect of accident risks. The inspectors are also mandated to verify the existence of sufficient occupational health services as prescribed by the Occupational Health Services Act for all employees. The occupational health services are typically provided by enterprise-owned medical departments, by mutually owned health care centers, by private practitioners, or by municipal health care centers. The latter are required by law to provide all services as prescribed by the legislation to anyone who comes to the facility. This situation is prevalent in the countryside, where there are very few private caregiving centers. Declaring occupational accidents and disease cases is mandatory, and the Inspection districts examine all accidents to establish causes and consequences, and to initiate prosecution in case of criminal negligence. Labour Inspection Districts are also notified of the new occupational disease cases as they are declared to insurance companies. Insurance for occupational disease, accidents, and death is an obligation of the employer, although they can choose the insurance company. The medical confidentiality between the workers and their occupational health care providers is very strict. Official statistics are maintained by the state Statistics Finland organization, and they may be used, for example, for research purposes by scientific institutes like the Finnish Institute of Occupational Health. Construction industry accounts for 25% of all fatal accidents (120 cases per 1 million working hours), followed by mechanical, wood, metal, machinery, and pulp and paper industry (10% each of fatal accidents) with rates ranging from 100–160 cases per 1 million working hours. There are some 5,000 occupational disease cases per year (rate 22/10,000 employed). The major disease categories include repetitive strain injuries (1,300 cases), respiratory allergies (600 cases), occupational skin diseases (1,000 cases), and 900 cases of noise-caused hearing loss. In 1998, 589 cases of asbestos-related diseases were reported.     

森林地表火蔓延模拟方法及其计算机实现

进行了森林火蔓延的研究,对传统的经验公式和模型进行改进,明显发现改进的模型有更好的结果,用计算机巧妙准确地实现了模拟模型,在风力不是特别大,地形变化不是特别剧烈时,该模型有较高精度;并结合火蔓延的主要因素（气象因子、气候、地形等）,进行系统分析,写出算地,编制实现地表火蔓延的预测预报计算机系统软件。这对于有效的组织扑救、减少火灾损失、计算森林火灾的损失评估有重要意义。     

公路隧道火灾逃生疏散研究

以苍岭隧道为背景,首先采用经验计算理论和计算软件building EXODUS相结合的方式,从被困人员的安全疏散时间、高温烟气的影响、隧道横通道的利用率以及人员的疏散行为特性进行了研究。结果表明:中小规模火灾情况下的安全疏散时间控制在8 min之内,高温烟气影响不大,但横通道的利用率不平均,且人员疏散路线相对集中。然后对存在的逃生疏散问题提出针对性建议以及其他相关建议,旨在为更大程度降低事故的严重性和经济财产损失。