BAF对再生水处理的中试研究

BAF用于处理沈阳市北部污水处理厂的出水,当水力停留时间(HRT)为2.0 h,水力负荷为2m3/m2·h时,CODcr、NH3-N、SS等的去除率分别为60%、98%、92%,其水质指标完全满足电厂补给水的水质要求,同时具有较高的处理效率和抗冲击负荷能力.     

内循环上流式厌氧污泥床启动研究

介绍了内循环上流式厌氧污泥床工艺及生产性实验启动的研究情况 ,就启动过程中发现的问题进行讨论 ,总结启动过程中应注意的事项     

页岩气田腐蚀特征、细菌来源及腐蚀对策

分析了国内外的页岩气田腐蚀案例及腐蚀特征,采用平行绝迹稀释法对某页岩气田生产整个流程的一系列水样开展了细菌测量,对细菌来源进行了溯源研究。结果表明:页岩气田的油管及集输系统普遍存在细菌腐蚀问题;从压裂到生产全流程,配置压裂液的水源、压裂液及返排水的水样中均含大量细菌,细菌的来源包括地面和井下。最后根据页岩气田腐蚀特征和细菌的来源,提出了相应的腐蚀控制对策。     

生物膜系统同时硝化和反硝化的实验研究

实验采用人工配水,对生物膜系统中COD和氮的去除进行了研究。实验中pH控制在7.0～7.5左右,温度为20℃～28℃。本实验研究了不同溶解氧、水力停留时间和碳氮比对总氮去除率的影响。实验结果表明,生物膜系统中同时硝化和反硝化具有一定的可行性。在C/N比为8∶1,水力停留时间6h时,溶解氧为0.5～1.0mg/L时,总氮的去除率达53.6%。     

Stability and Mixing of a Vertical Axisymmetric Buoyant Jet in Shallow Water

The stability, mixing and effect of downstream control on axisymmetric turbulent buoyant jets discharging vertically into shallow stagnant water is studied using 3D Reynolds-averaged Navier–Stokes equations (RANS) combined with a buoyancy-extended k –ε model. The steady axisymmetric turbulent flow, temperature (or tracer concentration) and turbulence fields are computed using the finite volume method on a high resolution grid. The numerical predictions demonstrate two generic flow patterns for different turbulent heated jet discharges and environmental parameters (i) a stable buoyant discharge with the mixed fluid leaving the vertical jet region in a surface warm water layer; and (ii) an unstable buoyant discharge with flow recirculation and re-entrainment of heated water. A stratified counterflow region always appears in the far-field for both stable and unstable buoyant discharges. Provided that the domain radius L exceeds about 6H, the near field interaction and hence discharge stability is governed chiefly by the jet momentum length scale to depth ratio l_M/H, regardless of downstream control. The near field jet stability criterion is determined to be l_M/H = 3.5. A radial internal hydraulic jump always exists beyond the surface impingement region, with a 3- to 6-fold increase in dilution across the jump compared with vertical buoyant jet mixing. The predicted stability category, velocity and temperature/concentration fields are well-supported by experiments of all previous investigators.     

污水排海工程的扩散器水力设计与模型试验研究

通过SZ36-1油田二期终端污水排海工程扩散器的水力设计，比较了扩散器的水力设计的两种计算方法，对水力计算中有关参数及局部阻力系数进行了选用，并通过模型试验进行了验证。表明所用计算方法及其结果是可信的，阻力系数的选取是合适的。     

EVALUATION OF STORMSEWER CONTROL ALGORITHMS USING A TRANSIENT MIXED FLOW MODEL1

ABSTRACT: a hydraulic transient model that is capable of simultaneously modeling open channel and pressurized flows is used to study active control of a deep tunnel stormwater collection system. The simultaneous occurrence of open channel flow and pressurized flow is termed mixed flow. This paper demonstrates the application of a mixed flow hydraulic model to the development of an active control scheme. It is shown that dynamic conditions can exist in a storm sewer system even under moderate inflow conditions and that these conditions, particularly at the time of full system pressurization, can influence the operation of the dynamic control, so that accurate hydraulic modeling is essential to proper control formulation.     

ALTERNATIVE APPROACH TO THE FORMULATION OF BASIN HYDRAULIC GEOMETRY EQUATIONS1

ABSTRACT: Along a drainage network, there is a systematic variation of average flow parameters (width, depth, and velocity) at flows having the same flow duration. Hydraulic geometry equations mathematically express this interdependent relationship of stream-flow characteristics for a basin for annual flow durations varying from 10 to 90 percent. However, the equations proposed so far have had rather poor predictive performance for low flows. An independent investigation of the variation of discharge with drainage area and annual flow duration demonstrates a consistent relationship between these parameters. The relationship for the high to median-flow range differs, however, from that for the median— to low-flow range. The proposed equations provide a better predictive performance for low flows than previous formulations and a versatile means of estimating flow parameters for streams throughout a basin. The improved basin hydraulic geometry equations have a wide range of applications in areas such as stream habitat assessment, water quality modeling, channel design, and stream restoration projects.     

MODELING PERCOLATION LOSSES FROM A PONDED FIELD UNDER VARIABLE WATER-TABLE CONDITIONS1

ABSTRACT: A numerical simulation model was developed to predict the vertical and lateral percolation losses from a ponded agricultural field. The two-dimensional steady-state unsaturated/ saturated flow equation was solved using the finite-difference technique. A constant ponding depth was maintained at the soil surface with different water table conditions in an application of the model for rice fields bordered by bunds. Field experiments were conducted for two different water table depths to collect data on the spatial distribution of volumetric soil-moisture content for model verification. The measured soil-moisture content values were found to be in close agreement with those predicted by the model. The sensitivity analysis of the model with selected hydrologic conditions shows that the model is most sensitive to the values of saturated hydraulic conductivity, but relatively less sensitive to water table depth, ponding depth, and evaporation rate from the soil surface. It implies that, in a ponded rice field condition, the lateral and vertical percolation losses are mostly governed by the hydraulic conductivity of the soil. The vertical percolation losses were almost equal to the saturated hydraulic conductivity values and, in most cases, these losses increased with deeper water table depths. The lateral percolation losses also increased with deeper water table depths; however, these losses were relatively small in comparison to the vertical percolation losses. The vertical and lateral percolation losses increased with the increase in ponding depths. The lateral percolation losses through the bund decreased when the evaporation losses increased from the soil surface. The results of this study indicate that the percolation losses from a ponded field may be predicted accurately for a wide range of soil and hydrological conditions when the values of hydraulic conductivity, evaporation rate, depth of ponding, and water table depth are accurately known.