專業(yè)英語(給排水與環(huán)境工程 李田)Unit 9

1、Unit 9Sedimentation p59新浪微博：南昌工程學(xué)院臾涼先森New words and expressionsnpotable adj. 可飲用的， potable water nClarification n. 澄清，凈化nclarifier n. 澄清池，澄清器開.napparatus n. 器械, 設(shè)備, 儀器n prechlorination n. 預(yù)氯化ninlet n. 進口nturbulent adj. 紊流的，湍流的nTurbulence n. 紊流，紊亂nperimeter n. 周長 圓周nweir n. 堰，溢流堰nlayout n. 規(guī)劃, 設(shè)計, (書

2、刊等)編排, 版面, (工廠的)布局圖nrectangular adj. 矩形的，成直角的2新浪微博：南昌工程學(xué)院臾涼先森New words and expressionsnInclined tube n. 斜管neffluent adj. 流出的 n.流出物, 出水nSpherical n. 球形的 球的ndeposit n. 沉淀物 堆積物 ；儲蓄 存款nReinforced concrete n. 鋼筋混凝土ncontroversial n. 爭論的 爭議的nInnovation n. 改革 創(chuàng)新ninclination adj. 傾斜, 彎曲, 傾度, 傾向, 愛好nhexagonal

3、 adj. 六角形的 六邊形的nbackwash n. v. 反洗 反沖洗nmodule n. 模數(shù)，模塊，組件3新浪微博：南昌工程學(xué)院臾涼先森nSedimentation or clarification is the removal of particulate matter, chemical floc, and precipitates from suspension through gravity settling.n沉淀和澄清是從懸浮物中通過重力沉降去除顆粒物、化學(xué)絮凝產(chǎn)物和凝結(jié)沉淀物。nThis makes water clarification a vitally import

4、ant step in the treatment of surface waters for potable supply and in most cases the main factor in determining the overall cost of treatment.n這使得水的澄清是飲用水供應(yīng)中地表水處理的至關(guān)重要一步，在很多情況下，它也是決定全部水處理費用中主要的因素。nPoor design of the sedimentation basin will result in reduced treatment efficiency that may subsequentl

5、y upset other operationsn糟糕的沉淀池設(shè)計將會導(dǎo)致降低處理效率，接下來這也許會影響到其它（水處理工藝）的運行。4新浪微博：南昌工程學(xué)院臾涼先森nSurface water containing high turbidity may require sedimentation prior to chemical treatment.n地表水（包含）在高濁度下就要求在化學(xué)處理工藝之前沉淀。nPresedimentation basins are constructed in excavated ground or out of steel or concrete. n預(yù)沉淀

6、池建在被挖坑的地下或用鋼筋混凝土建造。nSteel and concrete tanks are often equipped with a continuous mechanical sludge removal apparatus. n鋼筋混凝土池通常裝配有持續(xù)的機械除泥設(shè)施。5新浪微博：南昌工程學(xué)院臾涼先森nThe minimum recommended detention time for presedimentation is 3h, although at many times of the year, this may not be adequate to remove fine

7、 suspensions.n在預(yù)沉池，（被建議）規(guī)定的最短停留時間是3小時，盡管在一年的很多時候，這個時間可能不足夠去去除細小懸浮物質(zhì)。nChemical feed equipment may be provided ahead of presedimentation to provide prechlorination or partial coagulation for periods when water is too turbid to clarify by plain sedimentation.n當(dāng)通過平流池水太渾濁而不能澄清時，化學(xué)藥劑投加裝置就需要設(shè)置在預(yù)沉池之前去預(yù)加氯或者添

8、加部分的混凝劑。6新浪微博：南昌工程學(xué)院臾涼先森nSettling basins are usually provided for chemical coagulation or softening. n沉淀池通常投加一些混凝劑和軟化藥劑。nThese basins may be constructed of concrete or steel in a wide variety of shapes and flow mechanisms.n這些池子用鋼筋混凝土建成各種各樣的形狀和流動機制。nTo minimize the effects of short-circuiting and tur

9、bulent flow, care is taken in the effective hydraulic design of inlet and outlet structures in all tanks.n精心的考慮到所有池子進出口結(jié)構(gòu)的水力設(shè)計，去最小化短流與紊流的影響。7新浪微博：南昌工程學(xué)院臾涼先森nInlet structures are expected to: (1) uniformly distribute flow over the cross section of the settling zone; (2) initiate parallel or radial fl

10、ow; (3) minimize large-scale turbulence; and (4) preclude excessive velocities near the sludge zone. n進口結(jié)構(gòu)考慮部分包括以下幾點：（1）一致地（均勻地）分配到沉淀區(qū)域的各個部分（2）發(fā)起平行或輻射狀的流動（3）最小化產(chǎn)生大規(guī)模紊流（4）阻止靠近污泥的區(qū)域有過大的流速nFlow through a sedimentation basin enters at the top of the basin. n水流流經(jīng)沉淀池到達池子的頂部nIn some circular basins, the fl

11、ow may enter a central flocculating chamber of the basin, effluent flows vertically out over perimeter weirs.n在一些圓形的池子，水流將會流進池子中央的絮凝室，出流水流從周圍的圍堰垂直流出。8新浪微博：南昌工程學(xué)院臾涼先森nIn rectangular tanks water flows horizontally to an end weir for discharge.n在矩形的水池，水流水平地流向池子終點的出水堰。nAn efficiently designed vertical t

12、ank is more stable than a horizontal one. The rating of a vertical tank as related to the bulk settling velocity is usually 3.3 to 9.8 ft/h (1 to 3 m/h).n有效設(shè)計的豎流式沉淀池比平流池運行穩(wěn)定。豎流式沉淀池的速率與較大絮凝體的沉速有關(guān)，通常為3.3到9.8英尺/小時（1到3米/小時）9新浪微博：南昌工程學(xué)院臾涼先森nRecent developments have been made with the implementation of tu

13、be settling in the design of horizontal-flow settling tanks, which are said to overcome some of the previous difficulties and enable higher rates of sedimentation.n近期在平流沉淀池設(shè)計中，通過沉淀管的安裝取得了一些進步，據(jù)說這些進步克服了先前的困難和提高了沉淀效率。nUpflow solids contact clarifiers, and horizontal-flow basins may increase their volu

14、metric capacity 50 to 150 percent or more with the introduction of inclined tubes into their basins.n向上流的固體接觸到澄清池和平流式沉淀池會增加50%150%的處理能力，或者通過采用斜管沉淀池可以增加更多的處理能力。nSimilar or improved effluent quality is observed in these modified processes.n類似的或改善的出水水質(zhì)在這些改進的工藝中被研究觀察。10新浪微博：南昌工程學(xué)院臾涼先森nEffluent quality f

15、or any sedimentation process is dependent upon previous water quality, coagulants added, mixing, flocculation, and filtration. n一些沉淀工藝的出流水質(zhì)取決于進水水質(zhì)、混凝劑的投加、混合、絮凝和過濾。nWith the exception of presedimentation, sedimentation processes are usually preceded by coagulation and followed by filtration. n除了預(yù)沉淀工藝

16、，沉淀工藝通常先于混凝后于過濾。nTherefore, typical removals of regulated contaminants by sedimentation and filtration are reported according to coagulants used in conjunction with these processes for removal of a specific contaminant.n因此，通過沉淀和過濾工藝來去除典型污染物的去除率，是按照使用在這些工藝中去除特定污染物的混凝劑來確定的。11新浪微博：南昌工程學(xué)院臾涼先森nBasically,

17、 the theory of sedimentation is the theory of the effect of gravity on particles suspended in a liquid of lesser density. n從根本上說，沉淀理論是顆粒物懸浮在比其密度更低的液體中，利用重力的作用沉淀。nUnder the influence of gravity, any particle having a density greater than 1.0 will settle in water at an accelerating velocity until the

18、resistance of the liquid equals the effective weight of the particle.n在重力的影響下，任何密度大于水的顆粒物將會以加速度在水中沉降，直到液體對顆粒物的阻力等于其自身重力時，（加速度才變?yōu)榱悖?。n Thereafter, the settling velocity will be essentially constant and will depend upon the size, shape, and density of the particle, as well as the density and viscosity

19、of the water.n此后，顆粒物的沉速本質(zhì)上將不會改變和其沉速取決于它的大小、形狀和密度，同樣取決于水的密度和粘滯性。12新浪微博：南昌工程學(xué)院臾涼先森nFor most theoretical and practical computations of settling velocities in sedimentation basins, the shape of the particles is assumed to be spherical. n在沉淀池中大部分沉速的理論和實踐計算，是假定顆粒物的形狀為球形（得出的）。nSettling velocities of partic

20、les of other shapes can be analyzed in relation to spheres.n其他形狀的顆粒物的沉速可以通過與球形的聯(lián)系來推斷分析。Paragraph five: 4-513新浪微博：南昌工程學(xué)院臾涼先森nNumber of Basins nProbably the most important considerations in the selection of the number of sedimentation basins are: (1) the effect upon the production of water if one basi

21、n is removed from service; and (2) the largest size which can be expected to produce satisfactory results.n選擇沉淀池數(shù)量最重要的因素可能是：n（1）假如一個池子不能工作對產(chǎn)水的影響n（2）供應(yīng)得到滿足的結(jié)果需要的最大尺寸14新浪微博：南昌工程學(xué)院臾涼先森nPlant layout and site conditions also may influence the number of basins.n水廠的設(shè)計和地理位置條件也會影響池子的數(shù)量。nFor any supply which requires coagulation and filtration for the production of safe water, a minimum of two basins should be provided. n對