污水处理厂沉淀池中的异重流

周边进水周边出水沉淀池具有表面负荷大、容积利用率高的特点。如何设计沉淀池的直径、配水槽孔口的大小与布置，使之达到配水均匀、提高容积利用率，是当前设计者所关心的问题。本文通过模型试验，探讨了沉淀池中异重流形成的主要原因及其运动规律，并总结出沉淀池中异重流环流半径的经验公式，可供设计者参考。     

双侧堰辐流式二沉池出水存在的问题及其机制分析

针对合肥市望塘污水处理厂辐流式二沉池集水渠附近有大量小絮凝体出现的情况,对集水渠附近的流速及沿池径方向SS指标进行了监测,分析了沉淀池的运行状况。结果表明,在辐流式二沉池的水面上,SS浓度最低的位置在距离池壁3.0～4.0 m之间;辐流式沉淀池进水流速较大,湍动能较大,不利于污泥沉降;沉淀池内存在明显的异重流,导致池壁处的上升流速较大,易将小絮凝体夹带至出水渠附近,导致出水效果不理想。     

周进周出二沉池设计之探讨

在分析周边进水周边出水幅流式沉淀池工艺特点的基础上,论述了该池型适用于由于进出水悬浮物浓度差所引起的异重流,容积利用率高,池子表面负荷可适当提高。通过对配水系统几种不同计算方法的比较,介绍了在保证配水均匀稳定性上的一些做法。     

渤海湾海水ACTIFLO(R)工艺预处理中试试验

天津是一个水质性缺水的沿海城市,处于渤海湾地区,海水自净能力差,污染状况较严重.为了解天津渤海湾海水水质情况,在天津塘沽海边进行了海水预处理中试试验,研究了ACTIFLO(R)高效斜板沉淀池对海水的预处理效果以及药剂投加量情况.结果表明ACTIFLO(R) SS的去除率为97.1％～99.2％;在原海水浊度变化较大情况下,可以将浊度控制在10 NTU以下;同时对藻类的平均去除率也达到91.6％.     

基于数值模拟的给水厂平流式沉淀池优化设计

应用FLUENT软件中的Mixture模型对某给水厂平流式沉淀池运行状况进行模拟。在沉淀池容积一定时改变沉淀池构造尺寸,得到不同工况沉淀去除效率并分析沉淀池尺寸变化对沉淀去除率影响,模拟结果表明池容积一定时沉淀池长宽变化对沉淀去除率影响较小,有效水深变化对沉淀去除率影响显著。应用MATLAB软件拟合出沉淀去除效率曲线、沉淀池费用曲线,构建较为合理的沉淀池优化设计模型,得出沉淀池最经济尺寸,在保证沉淀效率前提下实现年费用最小。     

渤海湾海水ACTIFLO~工艺预处理中试试验

天津是一个水质性缺水的沿海城市,处于渤海湾地区,海水自净能力差,污染状况较严重。为了解天津渤海湾海水水质情况,在天津塘沽海边进行了海水预处理中试试验,研究了ACTIFLO○R高效斜板沉淀池对海水的预处理效果以及药剂投加量情况。结果表明ACTIFLO○R对SS的去除率为97.1%~99.2%;在原海水浊度变化较大情况下,可以将浊度控制在10 NTU以下;同时对藻类的平均去除率也达到91.6%。     

海水组成的变化对海水直接电解的影响

主要讨论了海水组成的变化对海水直接电解过程的影响。海水的组成随季节、地点的变化而变化。当海水中氯离子浓度下降时，阳极的电极电位上升，同时电解过程的电流效率下降。当海水中钙镁离子浓度增加时，电流效率上升。     

油田注入水源与储层的化学配伍性研究

采取离子浓度变化分析及浊度法进行了天然海水与地层水的静态配伍性研究;应用岩心流动实验进行了动态配伍性研究.结果表明,涠12-1油田注入水源与地层水不配伍,且温度越高不配伍性越严重,对岩心损害程度越大;天然海水驱替过程中,随着驱替体积增加,累积结垢程度变大;天然海水与地层水交替驱对岩心损害严重,渗透率降低达32.3%.因此不能用天然海水直接作注入水源.     

海底管道试压过程管内海水温降影响因素分析

海底管道系统压力试验采用介质通常为温度较高的表层海水,表层海水和海底管道及周围环境的温差是延长试压时间、增加试压费用的根源。本文从理论计算和数值计量两个方面分析了管道类型、海水温度和海泥温度这三个因素对管内温度变化规律的影响,并在此基础上估算试压时间。结果表明:三种不同类型的海底管道在分析其温降规律后可将试压时间缩短20%左右;海水温度变化对试压过程的影响远大于海泥的影响,为降低工程费用,需减小试压海水温度。     

斜管(板)沉淀用于钢铁企业的问题分析及对策

斜管及斜板沉淀设施在钢铁企业水处理过程中得到了广泛的应用。总结了斜管及斜板沉淀池在多个钢厂水处理应用过程中存在的一些共同问题,并对问题的成因进行了分析。针对问题的成因,结合实际经验从沉淀池设计改进及管理措施强化两方面提出问题的解决对策。     

Lipids in sea water

Acidified and filtered sea water samples which were extracted with petroleum ether and ethyl acetate have been shown to contain a variety of lipid compounds in trace amounts. Concentrations of these solvent-soluble substances ranged from 0.5 to 6.0 mg/liter, the lower concentrations being found in offshore waters. The solvent extracts of the sea water were separated into eight lipid classes by column chromatography on silicic acid. The fractions eluted with solvents of increasing polarity were characterized by thin-layer chromatography, infrared and ultraviolet absorption and gas chromatography. These techniques revealed a complex mixture of alkanes, alkenes, fatty acids, steroids, phospholipids and many as yet unidentified components. Twenty to thirty alkanes were present as indicated by gas chromatography. No aromatic hydrocarbons were detected. Chromatography of the methyl esters of the fatty acids indicated the presence of acids with chain lengths varying from 14 to 22 carbons, both saturated and unsaturated. In many samples the unsaturated fatty acids containing 18 to 22 carbons predominated. The lipid components varied somewhat in composition as well as concentration from location to location and with season and depth.     

Investigation on sea water desalination plants in Spain

The main desalination research and development programs and the demand for fresh water on the Spanish coasts are outlined. The experimental plants of the Moncloa (Madrid) (MSF, vapor compression, reverse osmosis and others) and their computer programs are described as are also the pilot plants of Lanzarote (Canary Islands). The close collaboration between private enterprise and the Spanish Government is discussed.     

Drinking water from sea water by forward osmosis

Potable water may be extracted from a saline source, such as the ocean, using a concentrated solution of nutrients and a semipermeable membrane. This paper applies the previously presented theory (1) of the forward osmosis extractor to this case and compares that theory with experiment. Theory and experiment are found to match well. Calculated and observed magnitudes of water extraction rate and nutrient utilization indicate that practical devices may be constructed. It is found that the volume of water obtained per mass of nutrient meets the human requirement for fluids and nutrient. Optimization of the system is discussed.     

Viscosity of sea water solutions

The kinematic viscosity of sea water solutions and concentrates up to 11% salt by weight and from 0 to 200°C have been measured in a pressurized glass capillary viscometer. All precipitation was prevented during testing; carbonates and hydroxides by slight acidification (to pH 4.5) with concentrated (36N) sulfuric acid, and calcium sulfate by preheating and filtration under pressure. The precision of the results is ± 0.001 centistokes. Existing data on density of sea water solutions were correlated and used to calculate the dynamic viscosity in centipoises. Smoothed values presented should be accurate to ± 0.003 centipoises above 20°C and ± 0.005 below 20°. The results compare well with other authors' values for synthetic sea water.     

海水冷却塔设计

选择带冷却塔的循环冷却系统,采用海水作为循环冷却水的补充水,是我国沿海火力发电厂以及其它工业企业冷却用水的一次革命。它改变了从海洋取水使用后又将废水排回海洋的传统做法,避免了近海的热污染;极大的减少了从海洋取水的数量,节约了大量的基建投资。我国渤海湾地区拟建的超大型机组发电工程取水均在浅滩海岸,采用直流供水系统,取水头部将深入海中十几千米甚至更远,耗资将达到十几亿甚至几十亿元人民币。根据某科研设计单位十多年“海水冷却塔试验研究”的成果以及国际上成功的工程实践并结合国情,这些工程选择带冷却塔的海水闭式循环系统从方案和技术支持上是可行的,合理的。     

Energy-saving electro dialyzer for sea water desalination

Tokuyama Soda Co. ltd. has developed an energy-saving skid mounted electrodialyzer for sea water desalination. This equipment is suitable for making fresh water for drinking and industrial use. To desalinate 25°C sea water and turn out one ton of product water. This equipment consumes only 8.5 KWH of electricity and 0.09 Kg of concentrated sulfuric acid. Low energy consumption is achieved by adoption of low electric resistance membranes, new spacer and new designed one pass type system. Low running cost, easy maintenance and low initial installment cost place the equipment good position in the desalination field. And also we applied high temperature electrodialysis up to 50°C of sea water and get figure 6.0 KWH for one ton of product water.     

Vegetable composts for sea water uranium extraction

Composting wood or crop residues by the addition of tanneries sludge as nitrogen supplement yields products having lower polysaccharides and protein content, but higher relative concentration of lignin material than the starting mixture. When used as sea water uranium adsorbents, the compost products exhibit higher uranium uptake (3.0–100 μg g^?1) than parent ligno-cellulosic materials (0.3–9 μg g^?1), thus achieving over 10⁴-fold uranium concentration relative to sea water. An additional distinguishing feature is the strong pH effect observed on uptake by products. The results are consistent with the expected change of parent lignin to lignin-humus in the compost product.     

Desalination of sea water by direct osmosis

Sea water can be desalinated by direct osmosis across a cellulose acetate membrane by using the osmotic pressure of a hypertonic glucose solution as the energy source. The resulting glucose solution is potable. This may prove useful for an emergency water supply in lifeboats.     

Reverse osmosis in the desalination of brackish water and sea water

To make RO an economical process, plant and operating costs have been reduced by developing compact modules, led by polyamide hollow fibre modules which recover energy from the reject when desalinating highly saline brackish water and seawater. Such plants only start to pay their way at product rates of around 400m³ /d +. Energy costs for desalination systems with lower capacities can also be reduced considerably by operating the RO plants at conversion rates of more than 30%. To what extent the required higher conversion rates can be obtained for a particular application depends on concentration of scales-forming content matter (calcium sulphate, strontium sulphate, barium sulphate and calcium carbonate), salt content of the raw water, concentration of fouling substances such as iron, manganese, anorganic and organic matter, risk of biological growth due to algae, shells and bacteria. The scope and type of conditioning and pre-treatment are based on these factors.