A study on the hydraulics of waste stabilization pond

In this study, tracer tests and organic removal tests were conducted on three different ponds in the purpose of evaluating the influence of the flow velocity and dispersion on the hydraulic efficiency of the pond. The authors have compared the hydraulic flow patterns among ponds with different configurations. Experimental and theoretical analyses were performed. This study indicated that the flow characteristics of square ponds are different from that of baffled ponds; the flow velocity and dispersion are equally important factors which affect the pond hydraulics; the number of inserting baffles can be optimized; and the hydraulic efficiency of multistage ponds is superior to that of baffled ponds.     

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     

Morphology and electrical conductivity of PACS

Polyaluminium chlorides with sulfate ion(PACS) were prepared by using AlCl3· 6H2O, Al(SO4 )3· 18H2O and Na2CO3 as raw materials. The effects of basicity (r), Al3 +/SO42- molar ratio and aging time on the morphology of PACS were observed by transmission electrical microscope. The influence of aging time on charge neutralization and coagulation effect of PACS was studied.The effects of basicity (r), Al3+/SO42- molar ratio and aging time on the electrical conductivity of PACS solution were also investigated. The experimental results show that the degree of polymerization of polyaluminium chloride(PAC) increases when SO42-ion is added. The higher the basicity(r) and the longer the aging time, the larger the size of polymer PACS. The ability of PACS neutralizing the charge on Kaolinite decreases with the increase of aging time. The electrical conductivity of PACS solution (the concentration of Al3+ ion is 0.18 mol/L) with different aging time is the function of the basicity and Al3 +/SO42- molar ratios and has its maximum at r = 0.5 and Al3+/SO42- = 12.     

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%。     

广东大中型水库电导率分布特征及其受N、P营养盐的影响

广东省20座大中型水库的电导率在丰水期为22～246us／cm，在枯水期为23～254us/cm；除大境山水库外，其它水库丰水期、枯水期差别不大。在采样的6个流域中，受工业和生活污水污染比较严重的珠江三角洲水库电导率明显高于其它流域水库；东江流域电导率最低。N、P营养盐离子对水库电导率有不同的贡献，总的来说，营养盐质量浓度较高的水库，N、P营养盐离子对水库电导率的贡献率较大，水库电导率也较高。除粤西沿海的鹤地水库以NH4^ 对水库电导率的贡献为主外，其它流域以NO3^ 水库电导率的贡献最大。丰水期、枯水期营养盐离子对水库电导率贡献的结构有变化，PO4^3-对水库电导率贡献的结构变化最大，即PO4^3-在丰水期对电导率的贡献比枯水期明显增高。分析结果表明，广东省大中型水库的电导率反映了水库受污染的程度，富营养化是导致水库电导率上升的重要因素，水库电导率在一定程度上反映了水库的营养水平。     

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。     

用TDR确定沙壤土非饱和淹灌条件下NH_4~+的硝化反应及NO_3~-的入渗迁移

对于沙壤土柱实验，用ＴＤＲ（时间域反射计）结合土壤抽提液的溶质分析，研究了在非饱和灌溉条件下的硝化和ＮＯ－３的迁移．测得的土壤体电导率与土壤抽提液的电导率之比和土壤含水量成线性关系，籍此用ＴＤＲ可以确定非饱和灌溉条件下土壤中溶质浓度的变化规律；硝化过程是在土壤表层的不连通的小孔隙中进行的，几乎不受水分运动的影响；由示踪剂Ｂｒ－的入渗及土壤表层的ＮＯ－３（相当于ＴＤＲ测得的电导率值）入渗分布得出，入渗是按活塞推移作用进行的，借此方法可以研究非饱和入渗的机理．     

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.