给水排水专业英语

1Filtrationisusedtoseparatenonsettleablesolidsfromwaterandwastewaterbypassingitthroughaporousmedium.Themostcommonsystemisfiltrationthroughalayeredbedofgranularmedia,usuallyacoarseanthracitecoalunderlainbyfinersand.过滤是通过多孔介质被用来从水和废水中分离非沉降性固体的。最常见的系统是通过颗粒介质的分层床过滤，通常是位于精细砂子之下的粗糙的无烟煤。Gravitygranular-mediafiltrationGravityfiltrationthroughbedsofgranularmediaisthemostcommonmethodofremovingcolloidalimpuritiesinwaterprocessingandtertiarytreatmentofwastewater.[1]Themechanismsinvolvedinremovingsuspendedsolidsinagranular-mediafilterarecomplex,consistingofinterception,straining,flocculation,andsedimentation.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,surfacestrainingandinterstitialremovalresultinaccumulationofdepositsintheupperportionofthefiltermedia.Becauseofthereductioninoreare,thevelocityofwaterthroughtheremainingvoidsincreases,shearingoffpiecesofcapturedflocandcarryingimpuritiesdeeperintothefilterbed.Theeffectivezoneofremovalpassesdeeperanddeeperintothefilter.刚开始，表面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。Turbulenceandresultingincreasedparticlecontactwithintheporespromotesflocculation,resultingintrappingofthelargerflocparticles.Eventually,cleanbeddepthisnolongeravailableandbreakthroughoccurs,carryingsolidsoutintheunderflowandcausingterminationofthefilterrun.[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2的絮凝物颗粒的捕集。最终，清洁的滤层厚度不足，杂质发生穿透，底部出水携带固体颗粒，过滤周期结束。DirectfiltrationTheprocessofdirectfiltrationdoesnotincludesedimentationpriortofiltration.Theimpuritiesremovedfromthewaterarecollectedandstoredinthefilter.Althoughrapidmixingofchemicalsisnecessary,theflocculationstageiseithereliminatedorreducedtoamixingtimelessthan30min.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。Contactflocculationofthechemicallycoagulatedparticlesinthewatertakesplacesinthegranularmedia.Successfuladvancesindirectfiltrationareattributedtothedevelopmentofcoarse-to-finemultimediafilterswithgreatercapacityfor“in-depth”filtration,improvedbackwashingsystemsusingmechanicalorairagitationtoaidcleaningofthemedia,andtheavailabilityofbetterpolymercoagulants.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。Surfacewaterswithlowturbidityandcoloraremostsuitableforprocessingbydirectfiltration.Basedonexperiencescitedintheliterature,waterswithlessthan40unitsofcolor,turbidityconsistentlybelow5units,ironandmanganeseconcentrationsoflessthan0.3and0.05mg/L,respectively,andalgalcountsbelow2,000/mLcanbesuccessfullyprocessed.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验，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，以及藻类计数低于2000/mL的水可被成功地处理掉。Operationalproblemsindirectfiltrationareexpectedwhencolorexceeds40unitsorturbidityisgreaterthan15unitsonacontinuousbasis.Potentialproblemscanbealleviatedduringashortperiodoftimebyapplicationofadditionalpolymer.3Tertiaryfiltrationofwastewaterscontaining20-30mg/Lsuspendedsolidsfollowingbiologicaltreatmentcanbereducedtolessthan5mg/Lbydirectfiltration.[3]Forinactivationofvirusesandahighdegreeofbacterialdisinfection,filtrationofchemicallyconditionedwastewaterprecedesdisinfectionbychlorine.当色度超过40单位或者浊度大于15个单位时，在连续的基础上，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行三级过滤处理，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。Thefeasibilityoffiltrationwithoutpriorflocculationandsedimentationreliesonacomprehensivereviewofwaterqualitydata.Theincidentofhighturbiditiescausedbyrunofffromstormsandbloomsofalgaemustbeevaluated.Often,pilottestingisvaluableindeterminingefficiencyofdirectfiltrationcomparedtoconventionaltreatment,designoffiltermedia,andselectionofchemicalconditioning.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须进行评估。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。FilterBackwashingDuringtheservicecycleoffilteroperation,particulatematterremovedfromtheappliedwateraccumulatesonthesurfaceofthegrainsoffinemediaandintheporespacesbetweengrains.[4]Withcontinuedoperationofafilter,thematerialsremovedfromthewaterandstoredwithinthebedreducetheporosityofthebed.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表面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。Thishastwoeffectsonfilteroperation:itincreasestheheadlossthroughthefilter,anditincreasestheshearingstressesontheaccumulatedfloc.Eventuallythetotalhydraulicheadlossmayapproachorequaltheheadnecessarytoprovidethe4desiredflowratethroughthefilter,ortheremaybealeakageorbreakthroughofflocparticlesintothefiltereffluent.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。Justbeforeeitheriftheseoutcomescanoccur,thefiltershouldberemovedfromserviceforcleaning.Intheoldslow-sandfiltersthearrangementofsandparticlesisfinetocoarseinthedirectionoffiltration(down)；如果恰在此之前，这些结果中任何一种可能发生,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。mostoftheimpuritiesremovedfromthewatercollectonthetopsurfaceofthebed,whichcanbecleanedbymechanicalscrapingandremovalofabout12.7mmofsandandfloc.Inrapidsandfilte