CWD Dead-Zone Episodes

Residuals Handling at the Cleveland Division of Water

Scott Moegling- CWDDr. Stan Zachopoulos - MWH

1

1OUTLINEResidual Solids Management Plan RSMP (2014) Pilot-Scale Screw Press EvaluationResidual Disposal OptionsRecommendations22Cleveland Water SystemWest SideEast SideCrown PlantNottingham PlantMark Petrie PMDebbie Hanby PMCapacity: 112 MGDCapacity: 125 MGDParma ControlRich Papp - PM5000+ miles of pipe1.3 million peopleMorgan PlantBaldwin PlantTyrone Butler PMFrank Woyma PMCapacity: 150 MGDCapacity: 165 MGD

33Residual Solids Management Plan (2014)44Current Residuals Management StrategyBaldwin, Morgan Nottingham: Force main pumping to NEORSD sewer system of thickened solids from sedimentation basins and backwash clarifiersPermit limits4,000 mg/L TSS300 mg/L BOD512.5 tons/day Total Dry SolidsFlowrate 2 MGD to 4 MGDCrown: Beneficial reuse (through Emerald Environmental) of plate-and-frame press dewatered thickened solids from sedimentation basins and backwash clarifiers55Solids Production RatesDetermined performing a solids mass balance at each plant and comparing to reported residual discharge and production rates

Estimated Solids Production Rates: Morgan: 135 lbs/MG of water treatedBaldwin: 162 lbs/MGNottingham: 168 lbs/MGCrown: 172 lbs/MG66Evaluated Residual Solids Management OptionsStrategyBaldwinMorganNottinghamCrownSewer DischargeXXXLiquid Sludge HaulingXXXXDrying Bed DewateringXXXMechanical Dewatering (Screw Press)XXXMechanical Dewatering (Plate & Frame Press)X77Estimated Costs (2014)OptionCapital CostAnnualEACTPWBaldwinSewer Discharge$0$1,499,746$2,877,104$42,804,036Liquid Tanker (9% Solids)$2,237,124$1,204,945$1,355,315$20,163,663Drying Bed Dewatering$17,047,700$501,920$1,647,793$24,515,002Mechanical Dewatering$7,774,510$388,250$910,819$13,550,689NottinghamSewer Discharge$0$1,212,078$2,290,232$34,072,864Liquid Tanker$0$1,049,725$1,049,725$15,617,257Mechanical Dewatering$4,325,467$269,900$560,639$8,340,89788Estimated Costs (2014)OptionCapital CostAnnualEACTPWMorganSewer Discharge$0$811,970$1,568,510$23,335,461Liquid Tanker$0$779,085$779,085$11,590,818Drying Bed Dewatering$11,280,000$261,418$1,019,611$15,169,240Mechanical Dewatering$3,645,610$201,600$446,642$6,644,909CrownLiquid Tanker$0$740,280$740,280$11,013,497Drying Bed Dewatering$17,945,000$308,142$1,514,328$22,529,375Mechanical Dewatering$0$660,362$660,362$9,824,51999RSMP RecommendationsConsider screw press dewatering (assuming beneficial reuse will be available) Pilot-scale testing of screw press to determine:Process efficiencyPretreatment and chemical requirementsDesign parametersInstall screw presses at one plant (e.g., Morgan)Have a back-up plan for disposal/beneficial reuse of dewatered residualsMaintain sewer discharge as an alternative to dewateringEventually replace Crown plate-and-frame presses with screw presses1010Screw Press Evaluation1111Pilot-scale Screw Press EvaluationObjectivesDetermine dryness (% solids) of sludge cakePressate (filtrate) water qualitySolids capture efficiencyPolymer requirements (polymer type and dose)Optimal feed sludge concentration (hydraulic loading)Solids loading rateScrew size (diameter and length)Screw speedDischarge pressureOperation and maintenance requirements (e.g., lubrication, washing, etc.) 1212Pilot-scale Screw Press EvaluationScrew Press Evaluation was performed by MWH and AECOMScrew Presses Evaluated:A Schwing Bioset 300 screw press unitBaldwin water worksMorgan water worksA PWTech Volute ES201 unitMorgan water works1313Screw Press ComparisonSchwing Bioset PressAverage hydraulic feed capacity = 10 gpm (maximum hydraulic capacity = 30 gpm)Design dewatering rate = 100 dry lbs/hour

PWTech Volute PressHydraulic feed capacity = 15 gpmMaximum solids load = 80 dry lbs/hour

14Feed sludge pumpVelodyne polymer blend and activation systemPolymer mixing tankFlocculation tankPotable water connection for washing the pressAutomated operation control system.

14Schwing Bioset Press Flow Schematic15

15Schwing Bioset Press16

16Schwing Bioset Press

1717PWTech Volute Press Schematic18

18PWTech Volute Press19

19PWTech Volute Press20

20PWTech Volute Press21

21What you start with.

2222Polymer addition/coagulation

2323Injected into the screw press

2424What you hope for: 25-30% cake25

25Pressate

2626Testing and Sample AnalysesPolymers testedSchwing:Polydyne C-6266, 60% Charge - 41% ActivePolydyne C-6286, 80% Charge - 41% ActivePolydyne C-9530, 80% Charge - 41% ActivePWTech:Ciba 8812Ashland K1112727Testing and Sample AnalysesSampling Locations /Parameters AnalyzedFeed sludgeTotal SolidsSludge cakeTotal SolidsPressate (filtrate)TurbidityOrganics (TOC, UV254, SUVA, TTHMFP, HAA5FP, etc.)Inorganics (heavy metals, sulfates, chlorides, nitrates, etc.)2828Testing and Sample AnalysesSampling Locations/Parameters Analyzed (Cont.)*Operating parametersPolymer type and doseFeed sludge flowOperating press pressureScroll speedCondition tank speed

* Total Solids content in feed and dewatered sludge was determined both by the press operators (at trailer lab) and by CWD lab. For uniformity, the CWD lab data are reported.

2929Operating Conditions30ParameterBaldwin SchwingMorgan SchwingMorgan* PWTechFeed Flow (gpm)7 2910 2012Feed Sludge TS (%)0.3 1.10.250.42Active Polymer (lbs/dt)182427Scroll Speed (rpm)0.17 0.750.3 0.41.7 2.4Solids Throughput (lbs/hr)35 4450 10021Cone Pressure (psi)10080 100n/aCake Dry TS (%)252522* After Stabilization30Results31

31Results32

32Results33

33Results - Pressate34ParameterUnitBaldwin - SchwingMorgan - SchwingMorgan - PWTechIronmg/L3.674.431.54Supernatant*mg/L0.0860.0210.041Manganesemg/L2.350.990.53Supernatant*mg/L1.5830.0490.103Aluminummg/L1.641.515.34Supernatant*mg/L0.0410.0140.132TOCmg/L11.16.14.2DOCmg/L7.67.43.0UV2541/m0.00.11.9SUVAL/mg-m0.21.00.7TTHMFPug/L29.039.734Screw Press Test ConclusionsBoth presses could be used to dewater CWD residualsThe Schwing press operated effectively under a wide range of operating conditions (polymer selection bench-scale tests performed prior to pilot-scale testing)The PWTech press required more preparation (polymer optimization was performed during the pilot-scale study); after establishment of proper operating conditions, the press operated effectivelyPressate quality was similar for both pressesPressate quality at Morgan was better than Baldwin because the Morgan sludge was fresh (residuals at Baldwin were stored for prolonged time resulting in decomposition of various compounds and solubilization of metals)Settling of the pressate prior to recycling would substantially improve its quality3535Residual Disposal Options3636Screw Press Cost37DescriptionBaldwinNottinghamMorganCrownPWTech Screw Presses$7,608,769$4,053,524$3,899,817$5,371,856Schwing Screw Presses$9,207,786$5,255,000$4,626,851$6,497,71837Residual Disposal Options EvaluatedDischarge to the NEORSD sewer systemTransport thickened residuals at solids contents of:3%6%9%12%15%Installation of screw presses with disposal of the dewatered residuals:Through beneficial reuseTo a landfillPlate and frame dewatering at Crown with beneficial reuse

3838Sewer Discharge Cost39

39Estimated CostsOptionCapital CostAnnualEACTPWBaldwinSewer Discharge$0$1,926,788$3,316,157$49,336,036Liquid Tanker (6% Solids)$2,237,124$1,507,425$1,657,795$24,663,802Screw press dewatering (Beneficial reuse)$7,608,979 $445,250 $956,693$14,233,175Screw press dewatering (Landfill)$7,608,979 $1,360,250 $1,871,693$27,846,064NottinghamSewer Discharge$0$1,547,201$2,635,539$39,210,165Liquid Tanker$0$1,312,405$1,312,405$19,525,272Screw press dewatering (Beneficial reuse)$4,053,524 $322,400 $594,860$8,850,022Screw press dewatering (Landfill)$4,053,524 $1,117,400 $1,389,860$20,677,6154040Estimated CostsOptionCapital CostAnnualEACTPWMorganSewer Discharge$0$1,046,440$1,809,262$26,917,247Liquid Tanker$0$785,055$785,055$11,679,636Screw press dewatering (Beneficial reuse)$3,899,817 $233,600 $495,729$7,375,196Screw press dewatering (Landfill)$3,899,817 $708,600 $970,729$14,441,996CrownLiquid Tanker$0$740,280$740,280$11,013,497Plate&Frame dewatering (Beneficial reuse)$0 $660,362$660,362$9,824,519Screw press dewatering (Beneficial reuse)$5,371,856 $255,900 $616,973$9,179,001Screw press dewatering (Landfill)$5,371,856 $815,600 $1,176,673$17,505,9244141Typical Equiv. Annual Cost - Morgan42

3%9%12%6%15%SP - LandfillSP - ReuseNEORSD42Equivalent Annual Cost - Crown43

3%6%9%12%15%Plate and Frame - ReuseSP - ReuseSP - landfill43Recommendations4444RecommendationsDischarge to the sewer system is already the most expensive option; implement an alternative means for residuals disposalIdentify an alternative means for beneficial reuse of dewatered residualsShould an alternative option for beneficial reuse be identified, initiate installation of screw presses to all four water works in a staged approachTest gravity thickening to identify the maximum attainable solids content in the thickened sludge; if solids contents > 5% are possible, replace sewer discharge with liquid transport4545AcknowledgementsAECOM for assisting in operation, sample collectionBissNuss, Inc. Schwing representativePelton Environmental Products, Inc. PWTech representativeSchwing BiosetPWTechScrew Press operatorsBaldwin and Morgan staff for their assistanceCWD lab for sample analyses

4646