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1.
针对城市固废填埋场场地地下水污染的修复难题,提出氧气微纳米气泡(OMNB)曝气异位修复渗滤液污染地下水的方法.为研究该方法的效果,首先对渗滤液污染地下水开展OMNB曝气与氧气常规(OCB)曝气室内试验,通过对比两种曝气的传质效率、曝气前后水样的微生物活性和污染物浓度的变化研究了OMNB曝气的污染物去除效率,之后对OMNB曝气前后的水样进行紫外-可见光光谱(UV-VIS)、同步荧光光谱(SFS)和三维荧光光谱(3D-EEM)分析研究OMNB曝气前后水样中溶解性有机物(DOM)种类及浓度的变化.试验结果表明:OMNB曝气与OCB曝气的体积传质系数分别为0.265 s-1和0.005 s-1.在曝气后第30 d时,OMNB曝气与OCB曝气处理的水样的脱氢酶活性(DHA)分别提高了151%和84%,OMNB曝气处理水样的五日生化需氧量(BOD5)、化学需氧量(COD)和氨氮的去除率分别约为95%、50%和10%.OMNB曝气后,水样中DOM聚合度增加,芳香性、疏水性降低,水样中类蛋白物质和可溶性微生物产物的浓度显著降低.OMNB...  相似文献   

2.
地下水石油污染的原位空气曝气修复技术   总被引:1,自引:0,他引:1  
针对东北某石油污染场地水文地质条件进行模拟,按照试验场地地层现状进行实验室缩放。选取苯和二甲苯作为目标石油污染物,采用电阻层析成像技术测定空气曝气技术的影响半径,研究非均质介质砾砂、粗砂和中砂条件下,空气曝气技术对苯和二甲苯的去除效果。实验结果表明:在非均匀介质中的影响半径不是围绕曝气井呈中心对称分布的,存在气体偏流和绕流现象。空气曝气技术(AS)对中砂层中苯和二甲苯的去除效果要比砾砂层和粗砂层的好;曝气15 d后,AS对苯和二甲苯的去除率分别为75.6%和71.3%。AS在去除污染物的过程中,存在明显的拖尾现象。  相似文献   

3.
在阐明地下水曝气修复机理控制方程的基础上,对某污染场地地下水曝气修复中不同参数对气体流动形态的影响规律进行了数值模拟研究.结果表明:土体固有渗透率对曝气影响半径和分布形态有显著的影响,影响半径随土体固有渗透率的增大而减小;增加空气注入流量,曝气影响半径略有增大.当形成稳定流动形态后,再增加空气注入流量,曝气法影响半径提高有限;曝气影响半径基本不受地下水位线以下曝气井深度影响.实际工程中,曝气井位置应根据污染场地有机污染物分布深度确定;地下水流动对曝气井上游气体运移有抑制作用,对下游气体运动有放大作用,因此曝气法下游区域空气影响半径大于上游.  相似文献   

4.
傍河污染场地地下水修复技术筛选   总被引:2,自引:0,他引:2  
针对目前地下水修复技术方法众多,有着不同适用性和优缺点的情况,对不同的污染场地类型国内外尚未形成一套成熟的筛选机制.本文引入IOC(importance order of the criteria)筛选法,以地下水修复技术的修复成本、修复时长、技术有效性、技术可靠性、工人保护及人群保护为筛选指标,以吉林市某废弃工厂为研究区,在结合地下水污染调查和地下水人体健康风险评价的基础上确定了场地地下水的修复目标污染物,根据场地区域水文地质条件分析和目标污染物特性,结合抽出处理、曝气技术、渗透反应墙等地下水污染修复技术特点,筛选出合理的地下水污染修复方案.结果显示,场地地下水中苯并(a)芘的致癌风险超过单项污染物的可接受致癌风险限值,确定为修复目标污染物.经过IOC排序法分析确定,在有效性优先条件下,抽出-生物反应器法是理想的修复技术;在经济优先的条件下,地下水曝气技术适用于该场地的修复技术;综合有效性和经济优先2种条件,组合技术抽出-生物反应器法结合地下水曝气技术适宜于该场地的修复技术.  相似文献   

5.
气液两相流是好氧曝气过程中产生的一种复杂的气液流动形态,其流型、流态对曝气反应器的运行效率具有重要的影响。本研究使用高速摄影机获得气泡羽流的流场图像,再经图像处理和数值计算来研究气泡羽流的空隙率参数,测得空隙率值在气泡羽流中的分布,并结合羽流摆动频率对不同纵横比下的羽流运动情况进行分析。研究结果表明,当曝气装置纵横比为1.0时,气液两相流的流场分布均匀,频谱稳定,能形成稳定的气液环流,使气泡在液相中的停留时间变长,可以有效地提高氧传质的效率,改善曝气效果。  相似文献   

6.
利用二维模拟槽实验研究Tween80增溶作用对地下水循环井技术(GCW)修复萘的强化效果。分析Tween80在地下水中的迁移特性、强化修复过程中地下水循环井对Tween80的水力控制作用、Tween80对萘的增溶效果及最终强化修复效果。研究结果表明:Tween80注入地下水后,其垂向迁移距离明显大于横向迁移距离;地下水循环井能够对Tween80进行有效的水力控制,将其控制在循环井周围;Tween80注入24 h后,模拟槽内萘的质量浓度普遍上升,平均质量浓度由1.82 mg/L上升至3.62 mg/L;启动循环井修复后,增溶至水中的萘在水流作用下不断迁移流向循环井,并通过曝气吹脱去除,最终在循环井附近形成一个高效修复区域。萘的质量浓度经历快速下降-缓慢下降的修复过程,高效修复时间集中在曝气的前2 h内,地下水中萘的平均质量浓度降至1.98 mg/L,之后进入缓慢下降阶段,萘的拖尾质量浓度为0.69 mg/L。  相似文献   

7.
用生物膜方法修复受污染河道水   总被引:3,自引:0,他引:3       下载免费PDF全文
采用蜂窝陶瓷载体,形成生物膜反应器.分别用原位和异位方法对受污染的城市河道水进行生物修复.实验中比较了不同循环时间对水体中氨氮去除的影响,认为原位修复具有较好的效果,并确定了最佳的循环曝气时间.在循环曝气时间为2h/d条件下,原位修复对NH4-N平均日去除率为42%-53%,3d后可达100%,对COD,TN,TP的去除分别为59.4%,48.2%,31.5%,可使河道水中氨氮和总磷的指标达到Ⅱ类水的标准.  相似文献   

8.
典型污染物对微气泡曝气中氧传质特性的影响   总被引:3,自引:1,他引:2       下载免费PDF全文
微气泡曝气是一种新型的曝气方式,废水中的污染物对微气泡曝气中氧传质过程具有显著影响。采用气-水旋流微气泡发生装置进行空气微气泡曝气,考察了微气泡曝气中表面活性剂、油脂、苯酚、硝基苯、悬浮固体(高岭土)等典型污染物对氧传质的影响。结果表明,微气泡曝气和传统气泡曝气的表观状态具有明显差异,呈现乳浊状态。表面活性剂、豆油、苯酚、硝基苯等污染物均有助于微气泡的产生和稳定性,从而提高微气泡曝气的气含率和气泡平均停留时间。同时,这些污染物存在时,微气泡曝气氧传质系数为7.44~11.56h-1,α因子为0.77~1.20,显著高于传统气泡曝气。污染物对微气泡的形成和稳定性具有积极作用,可以克服其对氧传质过程的负面效应。气含率和污染物种类是影响微气泡曝气氧传质过程的重要因素。  相似文献   

9.
曝气生物滤池中生物膜的活性研究   总被引:15,自引:0,他引:15  
在上流式曝气生物滤池中,使用球形陶粒作填料,对城市生活污水进行处理.研究了在生物滤池中滤料上生物膜及滤料间生物絮体的活性.实验表明,滤料间生物絮体对有机物的去除和生物膜具有类似作用,曝气生物滤池对污水的处理是生物膜和生物絮体共同作用的结果,实验为曝气生物滤池运行机理及反冲洗时间的优化提供了理论依据。  相似文献   

10.
泄漏与旁路对管壳式换热器壳侧气液两相流流型的影响   总被引:3,自引:0,他引:3  
采用逐步放开流路的方法,应用空气-水两相混合物研究了泄漏与旁路对壳侧流型及流型转变特性的影响.研究表明,旁路C及泄漏流A对换热器壳侧的流型及流型转变特性的影响不明显,而泄漏流E对壳侧流型及流型转变特性有显著影响.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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