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1.
研究了不同质量浓度(1 mg/L和20 mg/h)多壁碳纳米管(Muhiwalled Carbon Nanotubes,MWCNTs)短期(21 d)作用对序批式活性污泥反应器(SBR)废水脱氮除磷效果的影响.结果表明,1mg/L和20mg/L MWCNTs废水的持续作用对反应器出水NH4+-N、NO3--N、NO2--N和TP质量浓度(分别为0.35 mg/L、4.5 mg/L、0.1 mg/L和0.15 mg/L)及1个反应周期内的氮磷转化过程并未产生明显的影响.活性污泥3h呼吸抑制试验表明,低质量浓度(ρ<100 mg/L)MWCNTs短暂作用(3h)对活性污泥活性并没有明显的抑制作用.但当MWC-NTs质量浓度达到g/L级别后,MWCNTs对活性污泥活性存在明显的抑制作用,而且MWCNTs对活性污泥的呼吸抑制作用与质量浓度呈正相关性.研究表明,1 mg/k和20 mg/L MWCNTs对活性污泥系统短期作用并不影响活性污泥系统脱氮除磷的效果.  相似文献   

2.
选择聚合氯化铝(PAC)、聚合硫酸铁(PFS)、聚合氯化铁(PFC)为絮凝剂,对比研究3种絮凝剂去除温室龟鳖养殖(greenhouse turtle aquaculture)废水悬浮物效果。结果表明,絮凝剂PAC的絮凝效果最佳。选择PAC为絮凝剂,阳离子聚丙烯酰胺(PAM)为助凝剂,通过响应面法以浊度去除率为响应值,PAC和PAM的投加量和搅拌时间为影响因素,对工艺关键参数进行优化,最终确定最佳工艺参数。根据响应面分析结果,确定龟鳖养殖废水的最佳絮凝条件为PAC质量浓度85.3 mg/L、PAM质量浓度19.8 mg/L、搅拌时间2 min。在此条件下浊度去除率为97.1%,为温室龟鳖养殖废水的优化絮凝处理提供了参考依据。  相似文献   

3.
以硫酸铝、硫酸铁、硅酸钠和阳离子聚丙烯酰胺(CPAM)为主要原料,采用共聚法制备了PSAF-CPAM高分子无机-有机复合絮凝剂,同时选取PSAF和市面上最常用的聚合氯化铝(PAC)作为对比,探究一种对印染废水具有高效除磷效果的新型复合絮凝剂。结果表明,PSAF-CPAM的最佳制备比例为无机絮凝剂与有机絮凝剂质量比为70 1,PSAF-CPAM对印染废水总磷的去除率随絮凝剂投加量的增加而逐渐增大,在絮凝剂投加量金属离子浓度达到1 mol/L后增长趋势变缓,总磷去除率均在98%以上。同时,通过电镜扫描(SEM)和傅立叶红外分析(IR)对PSAF-CPAM絮凝剂的形态与结构等进行表征分析,发现PSAF和CPAM之间发生了化学反应,并形成了新的聚合物,验证了PSAF-CPAM絮凝剂总磷去除效果较好的微观合理性。  相似文献   

4.
研究碳源和硝酸盐对填加聚氨酯载体的SBBR反硝化除磷的影响。在SBR中填加聚氨酯载体,将生物膜法和活性污泥法相结合,形成序批式生物膜反应器(SBBR),在厌氧/缺氧交替运行条件下利用NO3-作为电子受体,研究NaAc浓度、NaAc与丙酸钠的比例、NO3-浓度及NO3-投加方式等因素对除磷效果的影响。PO43-质量浓度在9~11 mg/L之间,COD质量浓度为200 mg/L时,SBBR有较佳的除磷效果;当进水NaAc与丙酸钠配比为2时,进水COD自身降解速率较慢,且不影响除磷效果;分批次(这里分2次)投加硝酸盐有利于硝酸盐向亚硝酸盐的转化;NO3-质量浓度为65 mg/L左右时,能获得较好的除磷、除氮效果。填加聚氨酯载体的SBR装置除磷效果较理想;碳源和硝酸盐对SBBR反硝化除磷影响显著。  相似文献   

5.
针对目前云南省某煤矿排放废水中Mn~(2+)超标的问题,利用一种新型复合材料进行除锰试验.该复合材料是纳米分子筛与硅藻土经合理复配后,掺入复配絮凝荆形成的.试验中优化了不同材料的复合方式、絮凝剂的复配比例与用量.利用复配的多孔材料,对云南某煤矿含有大量悬浮物、Mn~(2+)质量浓度为5.32 mg/L的黑色废水及Mn~(2+)质量浓度为42.mg/L的红褐色废水进行了Mn~(2+)去除效果研究.结果表明,黑色废水中Mn~(2+)去除率达到70%,出水pH值为7.9;红褐色废水中Mn~(2+)去除率达到91.0%,出水pH值为7.1.与此同时,还研究了废水中Fe~(3+)、固体悬浮物(SS)对Mn~(2+)去除效果的影响,废水中Fe~(3+)的存在使pH降低,并与Mn~(2+)产生竞争吸附,对复合材料除锰有不利影响,而SS的存在对Mn~(2+)的去除效果没有显著的影响.  相似文献   

6.
为了治理饮用水源地锑矿废水泄漏对水体的污染,使其达到饮用水水质标准,研究了聚合硫酸铁、氯化铁等3种混凝类物质及活性炭粉、蒙脱石粉等4种吸附类物质对含锑废水的处理效果.结果表明,聚合硫酸铁、氯化铁、硫酸亚铁对含锑废水具有良好的处理效果,去除率均达到90%以上.同时,进一步研究了聚合硫酸铁混凝结合硫化钠沉淀处理废水中的锑,废水经两级处理,废水中锑离子质量浓度从3.8400 mg/L降至0.002 7mg/L,达到国家《生活饮用水卫生标准》(GB 5749-2006)水质标准(Sb质量浓度<0.005 0 mg/L).  相似文献   

7.
实验研究了投加硅藻土对膜生物反应器处理校园生活废水效果的影响。两组膜生物反应器的对比实验结果表明:投加硅藻土有利于MBR工艺中活性污泥的培养和出水的稳定。投加硅藻土使MBR的出水COD质量浓度稳定在25 mg/L以下,BOD5质量浓度小于5 mg/L,NH3-N质量浓度0.4 mg/L左右,TP质量浓度小于0.5 mg/L,SS未检出,出水水质更加稳定。  相似文献   

8.
改性钢渣除磷试验研究   总被引:2,自引:0,他引:2  
研究了改性钢渣的吸附除磷效果。试验结果表明,钢渣对废水中的磷的去除率较高,当废水中磷质量浓度为10mg/L,pH值为弱酸或弱碱性条件下,钢渣的用量1g/100mL时,在15min内就可使残留液质量浓度降低到0.1mg/L,远远低于国家排放标准,去除率达到99%以上,对水体富营养化处理具有很重要的意义。  相似文献   

9.
生物反应器中投加含硅聚铁混凝剂的协同作用研究   总被引:1,自引:0,他引:1  
比较了将含硅聚铁混凝剂分别投加到反应器和出水中两种工艺对COD和磷的去除效果.结果表明: 混凝剂投加量在40 mg/L以下时,前者出水中的磷低于后者,此时将混凝剂投加到反应器中具有生物协同作用,30 mg/L时协同作用最明显; 当混凝剂的投加量增加到50 mg/L时两种工艺出水中的磷没有明显差别,不再具有生物协同作用; 混凝剂投加量为10~50 mg/L时,两种工艺的出水COD差别不大,没有协同作用.将混凝剂直接投加到反应器中可省去混凝、沉淀所需的设备及构筑物,从而节约投资.因此为提高对TP和COD的去除效果,可直接将混凝剂投加到生物反应器中.  相似文献   

10.
取吸附-生物降解(AB)工艺A段沉淀池出水,利用投加硫酸铝(AS)和聚丙烯酰胺(PAM)化学强化后的沉淀污泥进行除磷实验,考察沉淀污泥除磷效果和化学强化对污泥沉降性能的影响.结果表明:化学强化的沉淀污泥对污水的11P和浊度有较好的去除效果,其去除率随As投药量的增加而提高;当泥水比为66.7%,PAM为0.05mg/L,AS投药量(以Al2O3计,下同)为15.1 mg/L时,对TP和浊度的去除率分别为75.0%和60.9%;AS投药量从0 mg/L增加至15.1mg/L,沉淀污泥对COD去除率维持在23%~40%,对氨氮无去除作用;同一投药量(As为7.5 mg/L,PAM为0.05 mg/L)下,TP去除率随泥水比增大而提高,氨氮质量浓度无明显变化;投加AS和PAM化学强化除磷,污泥沉降比和体积指数随AS投药量增加而降低,污泥沉降性能提高.  相似文献   

11.
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.  相似文献   

12.
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。  相似文献   

13.
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.  相似文献   

14.
森林地表火蔓延模拟方法及其计算机实现   总被引:6,自引:1,他引:5  
杜飞  候遵泽  刘家琦 《火灾科学》2001,10(4):204-208
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。  相似文献   

15.
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。  相似文献   

16.
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).  相似文献   

17.
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。  相似文献   

18.
一起有机过氧化物爆炸事故的调查和分析   总被引:2,自引:0,他引:2  
阐述一起重大爆炸伤亡事故的现场调查和原因分析,介绍如何通过人证物证材料,用鱼刺图法找出可能引起事故的诸原因,逐项加以分析,将与人证或物证材料相矛盾的原因子以排除,最后剩下无法排除亦即能与人证物证相符的那个原因,就是事故的真正原因。笔者是这起事故调查专家组组长,取证和数据可靠。  相似文献   

19.
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.  相似文献   

20.
Occupational Safety and Health in Finland   总被引:1,自引:0,他引:1  
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.  相似文献   

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