HYDRAULIC HEADLOSS PREDICTIONS AS ... - mi …

1 HYDRAULIC HEADLOSS PREDICTIONS AS ITPREDICTIONS AS IT RELATES TO INFLUENT WASTEWATER SCREENSM ichigan Water Environment Wastewater Administrators CfF kthMIConference Frankenmuth, MI January 20, 2012 Presented by:Presented by:Steve AikenAgendag1. Background on hydraulics2. Driving Factors why you want the hydraulics modeling and modeling and resultsFEEL FREE TO BRING UPFEEL FREE TO BRING UP QUESTIONS AS THEY ARISEB ackgroundgManual screens or comminutors used tbthlto be the only way to remove debris from the influentfrom the influentWhen screens become blindedbecome blinded problems upstream canupstream can be catastrophicReasons for accurate HEADLOSS estimationheadloss estimation Allows proper selection of screening equipmentscreening equipment Allows proper operation of screening equipmentscreening equipment Required to properly size all

2 Elements associated with screening equipmentassociated with screening equipment (channel depth and width, geometry, etc.)BerezinskiBerezinskiBernoulliDarcyW eisbachDarcy-WeisbachHazen-WilliamsKihKi rschmerManning FelleniusSpanglerpgEscandeZimmermanZimme rmanCommonly Used EquationsyBernoulliHL= C-1(V2- 2) (2g)-1 KirschmerHL= (w/b) hsin Commonly Used EquationsyBernoulliHL= C-1(V2- 2) (2g)-1 KirschmerHL= (w/b) hsin Driving FactorsgConcerns or Issues to consider:Slot VelocitSlot Velocity As the velocity through the screen increases the debris capture rate decreasesConcerns or Issues to consider.

3 HYDRAULIC Bottleneck There is an increase in HEADLOSS with finer screens and the upstream water level a peak flow has to be taken into accountConcerns or Issues to consider:BlindingCleaning c cle times ha e to be Cleaning cycle times have to be considered as the screen can be clean one minute and blinded off theclean one minute and blinded off the nextHeadloss TestinggHeadloss vs. Approach VelocityMeasured Measured CalculatedTest SetupTest ChannelStorage TankPumpSlope AdjustmentSlope AdjustmentTesting SetupScreenAdjustable Overflow WeirTestinggTesting (cont.)gTesting(cont.)Testing (cont.)

4 Testing(cont.)Testing (cont.)Testing(cont.)Testing (cont.)Testing (cont.)gOriginal coefficientsRe ised coefficientsRevised coefficientsEquation Opening, mm [in] Bar Shape Trap RectTear Original 6 [ ] [ ] [ ] []Original C 6 [ ] [ ] [ ] [ ] CorporationHead Loss Vs Downstream Water Depth 25% Bl k dDate:1/3/2012 Bar [In]4014 BlockedProposal no.:P4584 Description: Missouli WWTPM achine Type:FPFSC lear [In]Channel FeetChannel Width:4 FeetMaximum [Ft^3/Hr]MontanaSite Address:3035401012]202568 Upstream Level [InHeadloss [In] Depth [FT]Average Flow MGDM inimum Flow 6 MGDS etteling Threshold 2 Setteling Threshold 3 Upstream level 6 MGDIn Conclusio