给水排水专业英语

1、. .Filtration is used to separate nonsettleable solids from water and wastewater by passing it through a porous medium. The most mon system is filtration through a layered bed of granular media, usually a coarse anthracite coal underlain by finer sand.过滤是通过多孔介质被用来从水和废水中别离非沉降性固体的。最常见的系统是通过颗粒介质的分层床过滤，

2、通常是位于精细砂子之下的粗糙的无烟煤。Gravity granular-media filtration Gravity filtration through beds of granular media is the most mon method of removing colloidal impurities in water processing and tertiary treatment of wastewater.1The mechanisms involved in removing suspended solids in a granular-media filter are

3、 plex, consisting of interception, straining, flocculation, and sedimentation.重力粒状介质过滤法通过粒状滤料床的重力过滤方法，是水处理和废水的三级处理中去除胶体杂质最常见的方法。涉及在粒状介质过滤除去悬浮固体的机制是复杂的，包括截取，伸展，絮凝和沉淀。Initially, surface straining and interstitial removal result in accumulation of deposits in the upper portion of the filter media.Becau

4、se of the reduction in ore are, the velocity of water through the remaining voids increases, shearing off pieces of captured floc and carrying impurities deeper into the filter bed. The effective zone of removal passes deeper and deeper into the filter. 刚开场，外表应变和间质的去除会导致沉积物在过滤介质的上面积累。由于矿砂的减少，通过剩余空隙的

5、水流速增加，进而剪断捕获的絮体片层，并且携带杂质进入更深的滤床。去除的有效区域越来越深进入到过滤器。Turbulence and resulting increased particle contact within the pores promotes flocculation, resulting in trapping of the larger floc particles. Eventually, clean bed depth is no longer available and breakthrough occurs, carrying solids out in the und

6、erflow and causing termination of the filter run. 2湍流和由此导致颗粒与毛孔接触的增加，促进了絮凝的形成，从而导致较大的絮凝物颗粒的捕集。最终，清洁的滤层厚度缺乏，杂质发生穿透，底部出水携带固体颗粒，过滤周期完毕。Direct filtration The process of direct filtration does not include sedimentation prior to filtration. The impurities removed from the water are collected and stored in

7、 the filter. Although rapid mixing of chemicals is necessary, the flocculation stage is either eliminated or reduced to a mixing time less than 30min.直接过滤直接过滤的过程不包括过滤之前的沉降。从水中去除的杂质被收集和储存在滤器中。虽然化学品的快速混合是必要的，但是絮凝阶段被消除或被降低到一个少于30分钟的混合时间。Contact flocculation of the chemically coagulated particles in the

8、 water takes places in the granular media. Successful advances in direct filtration are attributed to the development of coarse-to-fine multimedia filters with greater capacity for “in-depth filtration, improved backwashing systems using mechanical or air agitation to aid cleaning of the media, and

9、the availability of better polymer coagulants.在水中化学凝结物的接触性絮凝发生在颗粒介质中。直接过滤的成功进步归功于具有深层过滤的大容量的粗-细多介质的过滤器的改进，使用机械的或空气的搅动来辅助清洗介质的反洗系统的改善，以及更好的高分子混凝剂的可用性。Surface waters with low turbidity and color are most suitable for processing by direct filtration. Based on experiences cited in the literature, waters

10、 with less than 40 units of color, turbidity consistently below 5 units, iron and manganese concentrations of less than 0.3 and 0.05 mg/L, respectively, and algal counts below 2,000/mL can be successfully processed. 带有低色度和浊度的地表水是最适合直接过滤处理基于文献中所引用的经历，色度小于40单位，浊度始终低于5个单位，铁和锰的浓度分别小于0.3和0.05毫克/升，以及藻类计数低

11、于2000/mL的水可被成功地处理掉。Operational problems in direct filtration are expected when color exceeds 40 units or turbidity is greater than 15 units on a continuous basis.Potential problems can be alleviated during a short period of time by application of additional polymer. Tertiary filtration of wastewater

12、s containing 20-30mg/L suspended solids following biological treatment can be reduced to less than 5 mg/L by direct filtration.3 For inactivation of viruses and a high degree of bacterial disinfection, filtration of chemically conditioned wastewater precedes disinfection by chlorine.当色度超过40单位或者浊度大于1

13、5个单位时，在连续的根底上，直接过滤的操作问题可以被预测到。短时间内，通过应用添加的聚合物，潜在的问题可以得到缓解。对浓度为20-30mg/L悬浮物的生化处理出水进展三级过滤处理，经过直接过滤后，悬浮物能减少至5mg/L。对于病毒的灭活和细菌的高程度消毒，废水化学条件的过滤优于氯消毒。The feasibility of filtration without prior flocculation and sedimentation relies on a prehensive review of water quality data. The incident of high turbidit

14、ies caused by runoff from storms and blooms of algae must be evaluated. Often, pilot testing is valuable in determining efficiency of direct filtration pared to conventional treatment, design of filter media, and selection of chemical conditioning.还没有絮凝和沉淀的过滤可行性取决于水质数据的全面调查。由于来自风暴的径流和藻类大量繁殖引起的高浊度事件必

15、须进展评估。通常，试验性的测试在确定与传统处理相比的直接过滤效率，过滤介质的设计，化学条件的选择上是有价值的。Filter Backwashing During the service cycle of filter operation, particulate matter removed from the applied water accumulates on the surface of the grains of fine media and in the pore spaces between grains. 4 With continued operation of a filt

16、er, the materials removed from the water and stored within the bed reduce the porosity of the bed. 过滤器反洗在滤池的工作周期内，被去除的进水中的悬浮物，聚集在细颗粒滤料的外表以及颗粒间的空隙中。过滤器的连续工作，材料从水中被去除并存储过滤床中，由此降低了该床的孔隙率。This has two effects on filter operation: it increases the headloss through the filter, and it increases the shearin

17、g stresses on the accumulated floc.Eventually the total hydraulic headloss may approach or equal the head necessary to provide the desired flow rate through the filter, or there may be a leakage or breakthrough of floc particles into the filter effluent. 这对滤床运行工作有两个影响：它增加了通过过滤器的水头损失，并且增加了累积在絮凝物上的剪切应

18、力。最终总液压水头损失可能接近或等于通过过滤器必须提供所需流速的扬程,或可能有泄漏的或突破的絮状物粒子进入过滤器污水中。Just before either if these outes can occur, the filter should be removed from service for cleaning. In the old slow-sand filters the arrangement of sand particles is fine to coarse in the direction of filtration (down)；如果恰在此之前，这些结果中任何一种可能发

19、生,过滤器应该被移走送去清洗。在旧的慢速砂过滤器中，砂颗粒的排列在过滤向下的方向由细到粗。most of the impurities removed from the water collect on the top surface of the bed, which can be cleaned by mechanical scraping and removal of about 12.7 mm of sand and floc. In rapid sand filters, there is somewhat deeper penetration of particles into t

20、he bed because of the coarser media used and the higher flow rates employed.大局部从水中除去的杂质收集在过滤床的上外表，可以通过机械刮擦来清洗，并除掉大约12.7毫米的砂和絮体。在快速砂过滤器中，由于所用的介质较粗和采用的流速较高，所以有少量颗粒深层穿透进入过滤床。However, most of the materials are stored in the top few inches of a rapid sand filter bed. In dual-media and mixed-media beds, f

21、loc is stored throughout the bed depth to within a few inches of the bottom of the fine media.然而，大局部的杂质被存储在顶部几英寸的快速砂滤床中。在双介质和混合介质过滤床中床，絮状物被储存在整个床中优良介质底部深度在数英寸以内。Rapid sand, dual-media, and mixed-media filters are cleaned by hydraulic backwashing (up flow) with potable water. Thorough cleaning of the

22、 bed makes it advisable in the case of dual-or mixed-media filters to use auxiliary scour or so-called surface wash devices before or during the backwash cycle. 快速砂、双介质和混合介质的过滤器用饮用水由水力反洗向上流动清洗。就双或混合介质过滤器而言，在反冲洗周期期间或之前，使用辅助冲刷或所谓的外表清洗装置对过滤床的彻底清洗是合理的。Backwash flow rates of 36.6 to 48.8 m/h should be pr

23、ovided. A 20 to 50 percent expansion of the filter bed is usually adequate to suspend the bottom grains. The optimum rate of washwater application is a direct function of water temperature, as expansion of the bed varies inversely with viscosity of the washwater. For example, a backwash rate of 43.9

24、 m/h at 20 equates to 38.3 m/h at 5 and 48.8 m/h at 35 . The time required for plete washing varies from 3 to 15 minutes.36.6 to 48.8 m/h反洗水流速应该被提供。滤床20%到50%的扩展对于悬浮在底部的颗粒通常是足够的。反洗水应用的最优流速是一个水温的直接功能,如过滤床的扩展与冲洗水的粘度成反向变化。例如，在2043.9米/小时的反洗速率等于5时38.3米/小时的速率，以及35时48.8米/小时。完全清洗所需的时间从3到15分钟不等。Following the

25、washing process, water should be filtered to waste until the turbidity drops to an acceptable value.5Filter-to-waste outlets should be through an air-gap-to-waste drain, which may require from 2 to 20 minutes, depending on pretreatment and type of filter. 随着反冲洗的进展，冲洗水应当排入废水中，直到浊度下降到一个可承受的值为止。过滤废弃物应通

26、过一个空隙至废物的出口排放，这可能需要2到20分钟，这取决于预处理和过滤器的类型。This practice was discontinued for many years, but modern recording turbidimeters have shown that this operation is valuable in the production of a high-quality water.Operating the washed filter at a slow rate at the start of a filter run may acplish the same purpose. A recording turbidimeter for c