旋转流膜生物反应器特性的探索

通过人工配水方式对旋转切向流膜生物反应器与一体式膜生物反应器在CODCr去除率、NH3 N去除率、膜透水性能等方面进行了对比试验 ,研究表明虽然二者在有机物去除方面相差不大 ,但前者膜抗污染能力强、透水量大。     

连续流动分析仪法测定水中总氰化物

采用连续流动分析仪测定水中总氰化物。通过各类实际样品和标准样品的分析 ,该方法的检出限为0 0 0 2mg L ,相对标准偏差为 0 7%～ 3 0 % ,加标回收率为 96 0 %～ 10 6 0 %。实验表明 ,该方法具有灵敏度、准确度高 ,精密度和回收率好 ,节省试样、试剂等特点 ,并提高了操作的安全性、方便性及工作效率。适用于水质中总氰化物的测定。     

移动式卸料机除尘系统设计及应用

通过对移动式卸料机特性的分析及不同控制方案的比较,确定了卸料机除尘系统设计方案,打破了传统吹吸气流控制粉尘的方式,采用空气幕 排风联合的捕集方式对移动式卸料机进行除尘系统设计及应用,取得了较好的控制效果     

花山岩画渗水病害机理及环境治理对策

根据花山岩画区的水文地质与工程地质条件,分析了渗水病害的类型、危害及其形成机理。按水在崖壁上的运移方式将花山岩画的渗水病害分为裂隙渗水和面流水,着重分析了它们各自的危害和机理,提出了防渗堵漏、建立地表排水系统、修建立壁遮挡檐等防治对策。     

铁路客运站综合能源系统关键技术应用研究

随着近年来光伏发电、冷热电三联供、储能技术等在铁路客运站的应用逐渐增多,以分布式能源系统为基础的综合能源系统相关技术正在凭借其灵活高效、节能环保等优势推动传统的铁路能源管控系统改造升级.采用基于能量流的综合能源系统建模方法,对铁路客运站进行综合能源系统建模分析,提出不同情景下的系统运行优化控制策略,并基于某车站开发相应...     

基于陶瓷行业脱硫塔管束除雾器流速调控装置的设计研究

目的 针对陶瓷行业烟气"超净排放"须达到的标准(颗粒物浓度小于5 mg/Nm3)要求,创新设计管束除雾器流速调控装置结构.方法 在脱硫塔管束除雾器流速调控装置的出口末端均匀布置多组调节阀门,根据实际工况烟气量通过调节延伸在塔外的调节杆控制阀门启闭的数量,进而控制通过管束除雾器的总烟气量,实现单筒管束除雾器的筒内流速在设...     

基于有上下界风量约束的矿井风量极值流算法研究

为解决既有方法不能准确求出矿井最大通风量与最小配风量,从而导致矿井通风系统产生能源浪费或难以满足矿井通风需求,出现安全隐患与改造难度大、潜力低等问题,提出1种基于有上下界风量约束的矿井风量极值流算法.该算法首先利用最大流算法求解满足节点流量平衡与分支上下界容量限制条件的可行流问题,若存在可行流,在求得可行流基础上,再利...     

Single- and dual-porosity modelling of flow in reclaimed mine soil cores with embedded lignitic fragments

Lignitic mine soils represent a typical two-scale dual-porosity medium consisting of a technogenic mixture of overburden sediments that include lignitic components as dust and as porous fragments embedded within a mostly coarse-textured matrix. Flow and transport processes in such soils are not sufficiently understood to predict the course of soil reclamation or of mine drainage. The objective of this contribution is to identify the most appropriate conceptual model for describing small-scale heterogeneity effects on flow on the basis of the physical structure of the system. Multistep flow experiments on soil cores are analyzed using either mobile–immobile or mobile–mobile type 1D dual-porosity models, and a 3D numerical model that considers a local-scale distribution of fragments. Simulations are compared with time series' of upward infiltration and matric potential heads measured at two depths using miniature tensiometers. The 3D and the 1D dual-permeability models yielded comparable results as long as pressure heads are in local equilibrium; however, could describe either the upward infiltration or the matric potential curves but not both at the same time. The mobile–immobile type dual-porosity model failed to describe the data. A simultaneous match with pressure heads and upward infiltration data could only be obtained with the 1D dual-permeability model (i.e., mobile–mobile) by assuming an additional restriction of the inter-domain water transfer. These results indicate that for unsaturated flow conditions at higher matric potential heads (i.e., here >− 40 hPa), water in a restricted part of the fragment domain must be more mobile as compared to water in the sandy matrix domain. Closer inspections of the pore system and first neutron radiographic imaging support the hypothesis that a more continuous pore region exists at these pressure heads in the vicinity of the lignitic fragments possibly formed by fragment contacts and a lignitic dust interface-region between the two domains. The results suggest that the small-scale structure is too complex as to be represented by weighted contributions of individual components alone.     

A field experiment with variable-suction multi-compartment samplers to measure the spatio-temporal distribution of solute leaching in an agricultural soil

Solutes spread out in time and space as they move downwards from the soil surface with infiltrating water. Solute monitoring in the field is often limited to observations of resident concentrations, while flux concentrations govern the movement of solutes in soils. A recently developed multi-compartment sampler is capable of measuring fluxes at a high spatial resolution with minimal disturbance of the local pressure head field. The objective of this paper is to use this sampler to quantify the spatial and temporal variation of solute leaching below the root zone in an agricultural field under natural rainfall in winter and spring. We placed two samplers at 31 and 25 cm depth in an agricultural field, leaving the soil above undisturbed. Each sampler contained 100 separate cells of 31 × 31 mm. Water fluxes were measured every 5 min for each cell. We monitored leaching of a chloride pulse under natural rainfall by frequently extracting the collected leachate while leaving the samplers buried in situ. This experiment was followed by a dye tracer experiment. This setting yielded information that widely surpassed the information that can be provided by separate anionic and dye tracer trials, and solute transport monitoring by coring or suction cups. The detailed information provided by the samplers showed that percolation at the sampling depth started much faster (approximately 3 h after the start of rainfall) in initially wet soil (pressure head above − 65 cm) than in drier soil (more than 14 h at pressure heads below − 80 cm). At any time, 25% of the drainage passed through 5–6% of the sampled area, reflecting the effect of heterogeneity on the flow paths. The amount of solute carried by individual cells varied over four orders of magnitude. The lateral concentration differences were limited though. This suggests a convective–dispersive regime despite the short vertical travel distance. On the other hand, the dilution index indicates a slight tendency towards stochastic–convective transport at this depth. There was no evidence in the observed drainage patterns and dye stained profiles of significant disturbance of the flow field by the samplers.     

Variable-density flow in heterogeneous porous media — Laboratory experiments and numerical simulations

Konz, M., Ackerer, P., Younes, A., Huggenberger, P., Zechner, E., 2009a. 2D Stable Layered Laboratory-scale Experiments for Testing Density-coupled Flow Models. Water Resources Research, 45. doi:10.1029/2008WR007118., a series of laboratory-scale 2D tank experiments were conducted and accurately simulated for density driven flow problems on homogeneous porous media. In the present work, we extended the numerical and experimental studies to heterogeneous problems. The heterogeneous porous medium was constructed with a low permeability zone in the centre of the tank and had well-defined parameters and boundary conditions. Concentration distributions were measured in high resolution using a photometric method and an image analysis technique. The numerical model used for the simulations was based on efficient advanced approximations for both spatial and temporal discretizations. The Method Of Lines (MOL) was used to allow higher-order temporal discretization. Three different boundary conditions, corresponding to different localizations of the inflow and the outflow openings at the opposite edges of the tank, were applied to investigate different flow scenarios in the heterogeneous porous medium flow tank. Simulation results of all three density coupled experiments revealed a density-dependent behavior of dispersion. Thus, a reduction of dispersivites was required to obtain a good matching of the experimental data. The high quality of the experiments enabled a detailed testing of numerical variable-density flow codes under heterogeneous conditions. Therefore, the experiments were considered to be reliable benchmark tests.