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1、CLARIFIERSCLARIFIERSPrepared By Michigan Department of Environmental Quality Operator Training and Certification UnitProvide Quiescent AreaSeparation of Solids FloatableSettleableClarifiers Sedimentation Basins Settling TanksCLARIFIERSCLARIFIERSClarifiersEfficiency of Solids Removal Related To:1. Ch
2、aracteristics of the Solids2. Characteristics of the Water3. Characteristics of the ClarifierStokeStoke s Laws Law2(p - po)g9n(d/2)2VF = VF= Fall Velocity (p - po)= Density difference betweenparticle and water n= viscosity of water g= gravitational acceleration constant d= diameter of the particleSt
3、okeStoke s Laws LawVF= Fall Velocity (p - po)= Density difference betweenparticle and water n= viscosity of water g= gravitational acceleration constant d= diameter of the particleForget the FormulaForget the Formula Remember the Removal Remember the Removal Efficiency Depends on Several Efficiency
4、Depends on Several FactorsFactorsParticle Size versus Settling TimeParticle Size mmOrder of SizeTime to Settle1.0Coarse Sand3 Seconds0.1Fine Sand38 Seconds0.01Silt33 Minutes0.001Bacteria55 Hours0.0001Colloidal230 Days0.00001Colloidal6.3 YearsClarifiersEfficiency of Solids Removal Related To:1. Chara
5、cteristics of the Solids2. Characteristics of the Water3. Characteristics of the ClarifierStokeStoke s Laws LawVF= Fall Velocity (p - po)= Density difference betweenparticle and water n= viscosity of water g= gravitational acceleration constant d= diameter of the particleForget the FormulaForget the
6、 Formula Remember the Removal Remember the Removal Efficiency Depends on Several Efficiency Depends on Several FactorsFactorsWarm Water Less Dense Less ViscousSolids Settle More Readily in Warm Water Than in Cold WaterCold WaterMore Dense More ViscousWarm Water - Greater Efficiency of ClarificationS
7、ettling RateSettling RateCool Water- Less Efficiency of ClarificationClarifiersEfficiency of Solids Removal Related To:1. Characteristics of the Solids2. Characteristics of the Water3. Characteristics of the ClarifierClarifiersEfficiency of Solids Removal Related To:3. Characteristics of the Clarifi
8、erSurface Area Depth Hydraulic Loading Solids LoadingClarifiersEfficiency of Solids Removal Related To:3. Characteristics of the ClarifierSurface Area Depth Hydraulic Loading Solids Loading Design Operation MaintenanceClarifiersEfficiency of Solids Removal Related To:3. Characteristics of the Clarif
9、ierFlow Characteristics in the ClarifierFlow Must be Dispersed Evenly ThroughoutHigher Flow (Horizontal Velocity) in One Part of Tank(Detention Time vs. Fall Velocity)Density Currents Currents Within the Tank Carry Solids Through the Tank. Not the Same as Excessive Hydraulic LoadClarifier Short Circ
10、uitingClarifier Short CircuitingClarifier Short CircuitingClarifier Short CircuitingMissing or poor influent bafflingCausesClarifier Short CircuitingClarifier Short CircuitingMissing or poor influent bafflingCausesClarifier Short CircuitingClarifier Short CircuitingMissing or poor influent bafflingC
11、ausesClarifier Short CircuitingClarifier Short CircuitingUneven effluent weirs Plant growth or thrash in effluent weirsCausesClarifier Short CircuitingClarifier Short CircuitingTemperature stratification between influent & clarifier water temperatures.CausesClarifier Short CircuitingClarifier Short
12、CircuitingMonitoring for Short CircuitingVisual ObservationFlow Over Weir Solids Over Weir Clarifier Short CircuitingClarifier Short CircuitingMonitoring for Short CircuitingDye TestingHigher Flow (Horizontal Velocity) in One Part of TankDensity Currents Clarifier Short CircuitingClarifier Short Cir
13、cuitingClarifier Short CircuitingClarifier Short Circuiting Missing or poor influent baffling Uneven effluent weirs Plant growth or thrash in effluent weirs Temperature stratification between influent & clarifier water temperatures.CausesClarifiersEfficiency of Solids Removal Related To:1. Character
14、istics of the Solids2. Characteristics of the Water3. Characteristics of the ClarifierClarifiersTypes of ClarifiersTypes of ClarifiersInclined Plate (Lamella)RectangularCircularInclined Plate (Lamella)Overflow BoxClarifierInfluentSludge DischargeClarifier EffluentSludge HopperFlocculation TankFlash
15、Mix TankCoagulantFeedFeed BoxDischarge FlumesDistribution OrificeInclined PlatesTypes of ClarifiersTypes of Clarifiers Inclined Plate (Lamella)Inclined Plate (Lamella)Types of ClarifiersTypes of Clarifiers Inclined Plate (Lamella)Inclined Plate (Lamella)Increased settling efficiency due to increased
16、 surface areaSmaller Area Needed for InstallationTypes of ClarifiersTypes of Clarifiers Inclined Plate (Lamella)Inclined Plate (Lamella)Increased settling efficiency due to increased surface areaSmaller Area Needed for InstallationTypes of ClarifiersTypes of Clarifiers Inclined Plate (Lamella)Inclined Plate (Lamella)Seldom Used With Organic WastesBiological Growths Reduce EfficiencyMostly Industrial ApplicationsTypes of ClarifiersTypes of Clarifiers