Phosphorus Removal Via Phosphorus Removal Via Chemical Addition and Chemical Addition and

FiltrationFiltration

Waterborne EngineeringWaterborne Engineering

Colorado State UniversityColorado State University

AgendaAgenda

• Alternatives SummaryAlternatives Summary

• Decision AnalysisDecision Analysis

• Cost AnalysisCost Analysis

• Selected AlternativeSelected Alternative

• BioWin 3.1 ModelingBioWin 3.1 Modeling

• Summary/ConclusionSummary/Conclusion

• QuestionsQuestions

AlternativesAlternatives

• 2 Stage Chemical Addition2 Stage Chemical Addition

• Biological P Removal with Chemical Biological P Removal with Chemical AdditionAddition

• Tertiary Chemical Addition with Tertiary Chemical Addition with FiltrationFiltration

• Chemical Addition with Possible Chemical Addition with Possible Phosphoric Acid AdditionPhosphoric Acid Addition

Alternative 1 (2 Stage Alternative 1 (2 Stage Chemical Addition)Chemical Addition)

• Alum addition prior to final clarifier and prior to Alum addition prior to final clarifier and prior to filtersfilters

• Addition of chemical feed systems Addition of chemical feed systems

• Large increase in P rich sludge productionLarge increase in P rich sludge production

• Increased backwashing and maintenance on Increased backwashing and maintenance on filtersfilters

PrimaryClarifier

TricklingFilters

SolidsContact

AlumAddition

FinalClarifier

NTFs AlumAddition

DENITFilters

Disinfection

Alternative 2 (Biological P Alternative 2 (Biological P Removal with Chemical Removal with Chemical

Addition)Addition)

• Enhanced BPR with chemical addition for Enhanced BPR with chemical addition for polishingpolishing

• Addition of anaerobic tank creates an A/O process Addition of anaerobic tank creates an A/O process • May need to build additional tank May need to build additional tank • Chemical costs will be lowerChemical costs will be lower

PrimaryClarifier

TricklingFilters

SolidsContact

AnaerobicTank

FinalClarifier

NTFs AlumAddition

DENITFilters

Disinfection

Alternative 3 (Chemical Alternative 3 (Chemical Addition with Tertiary Addition with Tertiary

Filtration)Filtration)

• Chemical addition after DENIT filtersChemical addition after DENIT filters

• Addition of P removal filters Addition of P removal filters

• Does not affect biological processes of plantDoes not affect biological processes of plant

• Need to add chemical feed systemNeed to add chemical feed system

PrimaryClarifier

TricklingFilters

SolidsContact

FinalClarifier

NTFs AlumAddition

DENITFilters

DisinfectionDynaSand Filters

Alternative 4 (Chemical Addition Alternative 4 (Chemical Addition with Possible Phosphoric Acid with Possible Phosphoric Acid

Addition)Addition)

• Chemical addition prior to final clarifierChemical addition prior to final clarifier

• Addition of phosphoric acid prior to DENIT Addition of phosphoric acid prior to DENIT

• Need two chemical feed systems Need two chemical feed systems

• Large dose of coagulant prior to final clarifierLarge dose of coagulant prior to final clarifier

PrimaryClarifier

TricklingFilters

SolidsContact

FinalClarifier

NTFsAlumAddition

DENITFilters

DisinfectionPhosphoric Acid

Addition

Decision MatrixDecision Matrix

Decision Criteria and Decision Criteria and WeightsWeights

• Performance (100)Performance (100)

• Integration into Existing System (80) Integration into Existing System (80)

• Treatment Residuals (80)Treatment Residuals (80)

• Safety (80)Safety (80)

• Flexibility of Design (70)Flexibility of Design (70)

• Maintenance (70)Maintenance (70)

• Risk of Technology (60)Risk of Technology (60)

Alternative RatingsAlternative Ratings2 Stage Alum 2 Stage Alum

AdditionAdditionEnhanced Enhanced

BPRBPRAlum Addition Alum Addition with Filtrationwith Filtration

Alum and Alum and HH33POPO4 4 AdditionAddition

Performance Performance (100)(100) 9595 9090 100100 8080Integration Integration into Ex Sys into Ex Sys (80)(80)

5050 5555 7070 4545

Treatment Treatment Residuals (80)Residuals (80) 3535 6060 4040 4545Safety (80)Safety (80) 7070 8080 7575 6565Flex. Of Flex. Of Design (70)Design (70) 6565 5555 6060 4545Maintenance Maintenance (70)(70) 4040 6060 5050 6565Risk of Tech Risk of Tech (60)(60) 6060 4040 5555 3030

Scoring ResultsScoring Results

Sensitivity of ScoresSensitivity of Scores

• If % to crossover is less than 5%, then If % to crossover is less than 5%, then need to reassess model structure, weights, need to reassess model structure, weights, and scoresand scores

• Treatment Residuals: 5.5%Treatment Residuals: 5.5%• Integration into Existing System: 8.7%Integration into Existing System: 8.7%• Risk of Technology: 9.1%Risk of Technology: 9.1% • Maintenance: 10.6% Maintenance: 10.6% • Performance: 13.1% Performance: 13.1% • Safety: 18.5%Safety: 18.5%• Flexibility of Design: 33.5%Flexibility of Design: 33.5%

Life-Cycle Cost Analysis Life-Cycle Cost Analysis (LCCA)(LCCA)

• Evaluation of economic effects of Evaluation of economic effects of alternative designs and expressing alternative designs and expressing them in dollar amountsthem in dollar amounts

• Costs to analyze for each alternative: Costs to analyze for each alternative: – Initial: Purchase, Construction, Initial: Purchase, Construction,

EngineeringEngineering– Enduring: Operation, Maintenance, Enduring: Operation, Maintenance,

Energy, Chemicals, Sludge RemovalEnergy, Chemicals, Sludge Removal

Cost AnalysisCost AnalysisAlternativeAlternative Capital CostCapital Cost O & M CostO & M Cost ENG/Cont ENG/Cont

CostCost Total CostsTotal Costs

2 Stage 2 Stage Alum Alum

AdditionAddition $2.13M$2.13M $1.40M$1.40M $604K$604K $4.02M$4.02M

Enhanced Enhanced BPRBPR $8.61M$8.61M $682K$682K $2.48M$2.48M $11.8M$11.8M

Alum Alum Addition Addition

with with FiltrationFiltration

$6.01M$6.01M $902K$902K $1.80M$1.80M $8.71M$8.71M

Alum and Alum and HH33POPO4 4

AdditionAddition $2.01M$2.01M $1.53M$1.53M $604K$604K $4.14M$4.14M

In Depth Cost AnalysisIn Depth Cost AnalysisIn Depth CostsIn Depth Costs 2 Stage Alum Addition2 Stage Alum Addition Enhanced BPREnhanced BPR Alum Addition Alum Addition

with Filtrationwith FiltrationAlum and Alum and

HH33POPO4 4 AdditionAddition

ChemicalsChemicals $750K $750K $350K$350K $650K$650K $850K$850K

Feed and Storage Feed and Storage Facility:Facility: $763K$763K $381K$381K $381K$381K $763K$763K

Additional Feed Points:Additional Feed Points: $250K$250K $125K$125K $125K$125K $250K$250K

Energy:Energy: $101K$101K $430K$430K $300K$300K $101K$101K

Maintenance: Maintenance: $552K$552K $251K$251K $351K$351K $573K$573K

Additional Anaerobic Additional Anaerobic Tank:Tank: N/AN/A $7.0M$7.0M N/AN/A N/AN/A

Additional Filters:Additional Filters: N/AN/A N/AN/A $4.5M$4.5M N/AN/A

Recommended AlternativeRecommended Alternative

• Tertiary alum addition with filtration Tertiary alum addition with filtration

• Adding chemicals prior to biological Adding chemicals prior to biological processes may cause upsetsprocesses may cause upsets

• Parkson DynaSand Granular Media Parkson DynaSand Granular Media Filter (commonly used in WWTPs for Filter (commonly used in WWTPs for P removal)P removal)

DynaSand FilterDynaSand Filter

Alternative LocationAlternative Location

Alum Storage Facility

Alum Addition

DynaSand Filters

Alum Addition

P Removal

Filters

Design Using BioWin 3.1 Design Using BioWin 3.1 ModelingModeling

• Began model after denitrification Began model after denitrification

• Denitrification effluent P concentration of 2.70 Denitrification effluent P concentration of 2.70 mg/Lmg/L

• Able to optimize alum dose based on P removal Able to optimize alum dose based on P removal goalgoal

DENIT Effluent

Alum Addition

EffluentNull Bioreactor DynaSand Filters

Filter Sludge

Alum Dose and P RemovalAlum Dose and P Removal

Alum DoseAlum Dose Mass of Mass of Alum UsedAlum Used

Effluent P Effluent P Conc.Conc.

Annual Annual CostCost

150 mg/L150 mg/L 31,185 31,185 lbs/daylbs/day 0.04 mg/L0.04 mg/L $569,000$569,000

109 mg/L109 mg/L 22,261 22,261 lbs/daylbs/day 0.13 mg/L0.13 mg/L $414,000$414,000

65 mg/L65 mg/L 13,514 13,514 lbs/daylbs/day 0.70 mg/L0.70 mg/L $247,000$247,000

SummarySummary

• Tertiary alum addition with filtration Tertiary alum addition with filtration

• Does not disrupt nitrification/denitrification Does not disrupt nitrification/denitrification processesprocesses

• Allows for flexibility in P removal Allows for flexibility in P removal

• Used by numerous WWTPs throughout the Used by numerous WWTPs throughout the US with excellent resultsUS with excellent results

Questions?Questions?