TCE recovery mechanisms using micellar and alcohol solutions: phase diagrams and sand column experiments

Forty-one phase diagrams and fifteen sand column experiments were conducted to evaluate the efficiency of three types of washing solutions to recover trichloroethylene (TCE) at residual saturation and to identify the recovery mechanisms involved. This study demonstrates that: (1) an alcohol and a surfactant combination is more efficient than an alcohol used alone in water; (2) the prediction of the dominant recovery mechanism from the tie line slopes in phase diagram is accurate and can be reproduced in sand column experiments; and (3) TCE recovery efficiency in sand column experiments is generally well represented by the position of the miscibility curve in phase diagrams in the low concentration range. However, the miscibility curve alone is not sufficient to exactly predict the TCE recovery mechanisms involved. Tie line slopes and the critical tie line have to be taken into consideration to select the active matter as well as its concentration and to predict the dominant recovery mechanism in sand column experiments. The sand column experiments quantified the recovery efficiency of each solution and identified the proportion of the recovery mechanisms (mobilisation vs. solubilisation). Washing solutions with an active matter concentration above the critical tie line caused dominating mobilisation. Mobilisation was also dominant when the active matter of the washing solution partitioned into the organic phase and the active matter concentration was below the critical tie line. Solubilisation and emulsification were dominant for washing solutions containing active matter, which principally partitioned into the aqueous phase and an active matter concentration below the critical tie line.     

Variable-density groundwater flow and solute transport in heterogeneous porous media: approaches, resolutions and future challenges

In certain hydrogeological situations, fluid density variations occur because of changes in the solute or colloidal concentration, temperature, and pressure of the groundwater. These include seawater intrusion, high-level radioactive waste disposal, groundwater contamination, and geothermal energy production. When the density of the invading fluid is greater than that of the ambient one, density-driven free convection can lead to transport of heat and solutes over larger spatial scales and significantly shorter time scales than compared with diffusion alone. Beginning with the work of Lord Rayleigh in 1916, thermal and solute instabilities in homogeneous media have been studied in detail for almost a century. Recently, these theoretical and experimental studies have been applied in the study of groundwater phenomena, where the assumptions of homogeneity and isotropy rarely, if ever, apply. The critical role that heterogeneity plays in the onset as well as the growth and/or decay of convective motion is discussed by way of a review of pertinent literature and numerical simulations performed using a variable-density flow and solute transport numerical code. Different styles of heterogeneity are considered and range from continuously "trending" heterogeneity (sinusoidal and stochastic permeability distributions) to discretely fractured geologic media. Results indicate that both the onset of instabilities and their subsequent growth and decay are intimately related to the structure and variance of the permeability field. While disordered heterogeneity tends to dissipate convection through dispersive mixing, an ordered heterogeneity (e.g., sets of vertical fractures) allows instabilities to propagate at modest combinations of fracture aperture and separation distances. Despite a clearer understanding of the processes that control the onset and propagation of instabilities, resultant plume patterns and their migration rates and pathways do not appear amenable to prediction at present. The classical Rayleigh number used to predict the occurrence of instabilities fails, in most cases, when heterogeneous conditions prevail. The incorporation of key characteristics of the heterogeneous permeability field into relevant stability criteria and numerical models remains a challenge for future research.     

大连港3号排污口对海水的油污染及其扩散分析

本文通过１年的监测数据，初步分析季大连港３号排污口对附近海水的油污染状况，海水的油浓度与油类排放量的关系，以及油污染物迁移扩散的规律。     

作业工人长期接触低浓度氨二氧化硫对健康的影响

目的:探讨作业工人长期接触低浓度氨、二氧化硫对健康的影响.方法:对162名长期接触低浓度氨、二氧化硫作业者的健康监护体检资料及作业环境监测数据进行分析.结果:两种有毒物质对健康的影响主要表现为慢性鼻炎、慢性咽炎、咳嗽.其它还有胸闷和神经衰弱综合征.结论:氨、二氧化硫长期低浓度接触产生联合作用,对上呼吸道粘膜有刺激作用,应采取相应的防护措施.     

过滤—厌氧—好氧工艺处理酒精废水

介绍了酒精废水的高效低耗处理工艺，即首先用转鼓滤机去除60％左右的悬浮物并回收作粗饲料；其次，借助原水高温特点，用完全混合式高温厌氧池使废水充分消化；再次，用沉淀池和气浮池实现废水和厌氧污泥的完全分离，使废水的COD降解了92％－94％；最后为好氧处理工段，整个工艺对COD和SS的去除率分别高达99％和99．8％，不仅处理率高，而且能耗很低，还可以回收粗饲料和沼气能源。     

ArcGIS Engine支持下的排污口管理与水质预测信息系统的实现

从区域水环境管理的要求出发，对利用ArcGIS Engine开发的排污口管理与水质预测信息系统的开发过程进行介绍。简要介绍了该系统的目标、组成和主要功能，并从数据库建立、数据管理子系统、排污口管理子系统、水质预测子系统功能实现等方面对系统实现做了较为详细的阐述。     

炼油厂污水的综合治理

随着炼油厂生产的发展，产生的高污染负荷污水增加了污水场的处理难度。文中就高浓度污水采取预处理措施减少污染负荷，及改进污水处理工艺提高污水处理能力进行探讨，并提出本厂污水综合治理方案。     

Experimental analysis of a nitrogen removal process simulation of wastewater land treatment under three different wheat planting densities

Nitrogen contaminant transport,transformation and uptake simulation experiments were conducted in green house under three different planting density of winter wheat.They were Group A,planting density of 0.0208 plants/cm^2,Group B,0.1042 plants/cm^2,and Group C,0.1415 plants/cm^2.The capacity and ratio of nitrogen removal were different on three kinds of conditions of wastewater land treatment.From analysis of wastewater treatment capacity,wastewater concentration and irrigation intensity for Group C were suitable and nitrogen quantity added was 2 times of that for Group B,2.6 times for Group A while nitrogen residue was only 7.06%.Hence,wastewater irrigation and treatment design with purpose of waste water treatment should select the design with maximum capacity,optimal removal ratio and least residue in soil,which was closely related to crop planting density,crop growth status and also background nitrogen quantity in soil.     

节理化岩体结构面分布密度的确定方法及其应用

目前众多的科研与工程人员都采用岩体结构面统计分析和计算机随机模拟的手段来研究节理化岩体的工程性质,然而许多人忽略了岩体结构面密度具各向异性特征以及野外实际测量条件与理论情况还存在一定的差异,在计算中采用的结构面密度值不尽合理,常常导致分析结论有失偏颇。针对这一情况,充分考虑了结构面“方向校正”和“迹长截尾校正”,并根据野外测线长度进行加权平均,提出了一套较为系统合理的结构面分布密度计算方法,并将其应用于工程实际,取得了较好的结果。     

TSP日平均浓度监测采样时间有效性研究

通过对诸暨市城区空气中总悬浮颗粒物（ＴＳＰ）采用不同的自动连续采样时间获得的日平均浓度对比研究发现，每日采样的时间只有达到１８小时以上，才能体现真实的日平均浓度。