waste product to resource – biosolids biosolids handling ... · pdf filewaste product to...

Waste Product to Resource Waste Product to Resource –– BiosolidsBiosolids Handling at City of Handling at City of

Wisconsin RapidsWisconsin Rapids

Wisconsin Wastewater OperatorsWisconsin Wastewater Operators’’ Association 46Association 46thth Annual ConferenceAnnual Conference

October 11, 2012October 11, 2012Presented by Phil Presented by Phil KorthKorth

2006 Wastewater Facility2006 Wastewater Facility

Screening/Grit RemovalScreening/Grit Removal Primary ClarificationPrimary Clarification Conventional Activated SludgeConventional Activated Sludge Final ClarificationFinal Clarification UV DisinfectionUV Disinfection

2006 Wastewater Facility2006 Wastewater Facility Sludge HandlingSludge Handling

Anaerobic Sludge Digestion Anaerobic Sludge Digestion –– 2 Primary 2 Primary DigestersDigesters

Gravity Belt Thickener for WASGravity Belt Thickener for WAS Liquid Sludge StorageLiquid Sludge Storage Contract Haul DisposalContract Haul Disposal

2006 WWTP Design Capacity2006 WWTP Design Capacity

Average Daily FlowAverage Daily Flow 5.16 mgd5.16 mgd BOD LoadBOD Load 8,927 lbs/day8,927 lbs/day TSS LoadTSS Load 9,272 lbs/day9,272 lbs/day

2006 WWTP Flows and Loads2006 WWTP Flows and Loads

Average Daily FlowAverage Daily Flow 4.0 mgd4.0 mgd BOD LoadBOD Load 11,177 lbs/daylbs/day TSS LoadTSS Load 7,063 lbs/day7,063 lbs/day

2006 Capacity Limitations2006 Capacity Limitations

Limited Activated Sludge CapacityLimited Activated Sludge Capacity Sludge Storage Tank Limited to 132 Days Sludge Storage Tank Limited to 132 Days

StorageStorage

What Happened?What Happened?

Ocean Spray Added Larger Juice LineOcean Spray Added Larger Juice Line High Strength Cranberry Waste Discharged High Strength Cranberry Waste Discharged

to Sewerto Sewer No Communication from Ocean SprayNo Communication from Ocean Spray

Communication RestoredCommunication Restored

Ocean Spray Planned Dried Cranberry Ocean Spray Planned Dried Cranberry ProductionProduction

Industrial Agreement ReachedIndustrial Agreement Reached Second Cranberry Company Requested Second Cranberry Company Requested

Annexation for Wastewater ServiceAnnexation for Wastewater Service

Design ConditionsDesign Conditions

5.28 MGD5.28 MGD BOD Load BOD Load –– 18,386 lbs/day18,386 lbs/day TSS Load TSS Load –– 10,994 lbs/day10,994 lbs/day TKN TKN –– 1,181 lbs/day1,181 lbs/day P P –– 177 lbs/day177 lbs/day

City Design PhilosophyCity Design Philosophy

Design for Projected ConditionsDesign for Projected Conditions Allow for Expansion on Site and in Allow for Expansion on Site and in

StructuresStructures Include Sustainable Features Where Include Sustainable Features Where

PracticalPracticalWWTP to be a Resource to CityWWTP to be a Resource to CityAttract Industry/JobsAttract Industry/JobsCapture Value in WasteCapture Value in Waste

Sludge Treatment AlternativesSludge Treatment Alternatives

Expand Mesophilic Anaerobic DigestionExpand Mesophilic Anaerobic Digestion Convert Anaerobic Digestion Process to Convert Anaerobic Digestion Process to

Temperature Phased Anaerobic Digestion Temperature Phased Anaerobic Digestion (TPAD)(TPAD)

Class A vs. Class BClass A vs. Class B

TPADTPAD

ProsProsReduce Fecal Coliforms to Class A LevelReduce Fecal Coliforms to Class A LevelHigher VSS DestructionHigher VSS Destruction

More BiogasMore Biogas

Less Sludge for DisposalLess Sludge for Disposal

ConsConsHigher Initial CostHigher Initial Cost

TPADTPAD

Design for Class ADesign for Class AConvert Existing Mesophilic Digesters to Convert Existing Mesophilic Digesters to

Thermophilic DigestersThermophilic DigestersUse Time/Temperature Criteria to Meet Class Use Time/Temperature Criteria to Meet Class

A RequirementsA RequirementsNew Mesophilic DigesterNew Mesophilic Digester

Sludge Handling/Storage Sludge Handling/Storage AlternativesAlternatives

Liquid Sludge StorageLiquid Sludge Storage Dewater Sludge/Cake StorageDewater Sludge/Cake Storage Dewater Sludge/Sludge Drying and StorageDewater Sludge/Sludge Drying and Storage


Liquid Sludge StorageLiquid Sludge Storage4% 4% -- 5% Solids5% SolidsTwo Large New Tanks RequiredTwo Large New Tanks RequiredHigh Cost DisposalHigh Cost Disposal

Dewater Sludge/Cake StorageDewater Sludge/Cake Storage18% 18% -- 22% Solids22% SolidsRemote Site RequiredRemote Site RequiredLower Cost DisposalLower Cost Disposal


Dewater Sludge/Sludge Drying and StorageDewater Sludge/Sludge Drying and Storage75% 75% -- 90% Solids90% SolidsRemote Site Remote Site –– Drying PadDrying PadLowest Cost DisposalLowest Cost DisposalClass A Class A –– Use as Soil Conditioner/LandscapingUse as Soil Conditioner/Landscaping

Sludge HandlingSludge Handling

Dewater and Drying SelectedDewater and Drying Selected Dewater at WWTPDewater at WWTP Store and Drying Pad in Industrial ParkStore and Drying Pad in Industrial Park Class A Sludge to be Used in City Class A Sludge to be Used in City

LandscapingLandscapingReduced CostReduced CostWaste to ResourceWaste to Resource

Biogas Utilization EvaluationBiogas Utilization Evaluation

TPAD Increases VSS Destruction and TPAD Increases VSS Destruction and Biogas ProductionBiogas Production

Biogas Production Exceeds the Need for Biogas Production Exceeds the Need for Digester Heating Digester Heating

Biogas Utilization AlternativesBiogas Utilization Alternatives

Digester Heating in Biogas BoilerDigester Heating in Biogas Boiler Biogas Engine Driven Equipment Biogas Engine Driven Equipment

(Blowers/Pumps)(Blowers/Pumps) Electrical GenerationElectrical Generation Combined Heat and PowerCombined Heat and Power

Biogas UtilizationBiogas Utilization

Combined Heat and Power SelectedCombined Heat and Power Selected Engine Generator Selected Based on Engine Generator Selected Based on

EfficiencyEfficiencyMicroturbines Evaluated but Had Lower Microturbines Evaluated but Had Lower

Overall EfficiencyOverall Efficiency

Engine GeneratorEngine Generator

Dual Fuel Operation Possible (Biogas and Dual Fuel Operation Possible (Biogas and Natural Gas)Natural Gas)

Heat Recovery from Engine CoolantHeat Recovery from Engine Coolant Heat Recovery from Engine ExhaustHeat Recovery from Engine Exhaust Overall Energy Efficiency = 83%Overall Energy Efficiency = 83% Biogas Boiler Available as BackBiogas Boiler Available as Back--upup

TPAD Process OperationTPAD Process Operation

Volatile Solids Reduction Volatile Solids Reduction –– 63.7%63.7%10% Improvement from Mesophilic Operation10% Improvement from Mesophilic Operation

TPAD Design FeaturesTPAD Design Features

Two Thermophilic TanksTwo Thermophilic Tanks Feed One Tank Each 24 HoursFeed One Tank Each 24 Hours Automated Feed SystemAutomated Feed System Complex PipingComplex Piping Simple OperationSimple Operation Sludge Feed Small Amounts Each HourSludge Feed Small Amounts Each Hour


Common Feed TankCommon Feed TankPrimary SludgePrimary SludgeThickened WASThickened WAS

Piped to Accept High Strength WastePiped to Accept High Strength Waste Caustic Feed for pH ControlCaustic Feed for pH Control


Automated Withdrawal SequenceAutomated Withdrawal SequenceMesophilic Sludge to DewateringMesophilic Sludge to DewateringThermophilic A Sludge to MesophilicThermophilic A Sludge to MesophilicFresh Sludge to Thermophilic AFresh Sludge to Thermophilic AThermophilic B Holds at 131Thermophilic B Holds at 131°°

FF..

Mesophilic Digester Has Cooling Heat Mesophilic Digester Has Cooling Heat ExchangerExchanger

Biogas ProductionBiogas Production

Biogas Production = 70,000 cubic feet/dayBiogas Production = 70,000 cubic feet/day48,000 cubic feet/day From Volatile Solids 48,000 cubic feet/day From Volatile Solids

DestructionDestruction22,000 cubic feet/day From High Strength 22,000 cubic feet/day From High Strength

Cranberry Waste Fed Directly to DigestersCranberry Waste Fed Directly to Digesters

Electrical GenerationElectrical Generation

Biogas Engine Provides 29% of Total Biogas Engine Provides 29% of Total Electrical DemandElectrical Demand

Biogas Engine Operates During Peak Biogas Engine Operates During Peak Demand Hours (8 AM to 9 PM)Demand Hours (8 AM to 9 PM)

Hot Water UsageHot Water Usage

Waste Heat from Biogas Engine Used for Waste Heat from Biogas Engine Used for Process Heat in BuildingProcess Heat in BuildingSludge HeatingSludge HeatingBuilding HeatBuilding Heat

Sludge DewateringSludge Dewatering

Rotary Press SelectedRotary Press Selected Enclosed System Enclosed System –– Low OdorLow Odor Low Water UseLow Water Use Can be Stopped For Truck UnloadingCan be Stopped For Truck Unloading


Land Available in Industrial Park for Land Available in Industrial Park for Storing and Air Drying SludgeStoring and Air Drying Sludge

Asphalt Pad Built by CityAsphalt Pad Built by City Runoff Collected in Basin with Outlet to Runoff Collected in Basin with Outlet to

Sanitary SewerSanitary Sewer Sludge Stored and Dried in WindrowsSludge Stored and Dried in Windrows


Dewatered Sludge Dewatered Sludge –– 18 18 –– 22% Solids 22% Solids ConcentrationConcentration

Drying Bed Sludge Drying Bed Sludge –– 86% Solids86% Solids

Class A PerformanceClass A Performance

Digester Feed Sludge Digester Feed Sludge –– 625,000 MPN Fecal 625,000 MPN Fecal ColiformColiform

Dewatered Sludge Dewatered Sludge -- <326 MPN Fecal <326 MPN Fecal ColiformColiform

Class A Requirement = <1,000 MPN FecalClass A Requirement = <1,000 MPN Fecal Time/Temperature = 24 hours at 131Time/Temperature = 24 hours at 131°°FF

SummarySummary

Before ProjectBefore ProjectBiosolids are Waste ProductBiosolids are Waste ProductHigh Cost for DisposalHigh Cost for DisposalRestrictions on HandlingRestrictions on HandlingSludge Handling Capacity LimitedSludge Handling Capacity Limited

SummarySummary

After ProjectAfter ProjectBiosolids are ResourceBiosolids are ResourceCapacity Available to Attract CustomersCapacity Available to Attract CustomersFuel to Make BiogasFuel to Make Biogas

ElectricityElectricity

Hot WaterHot Water

Class A BiosolidsClass A Biosolids

Low VolumeLow Volume

Soil AmendmentSoil Amendment

Safe to HandleSafe to Handle

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