TownofFalmouthMA

NewSilverBeachWastewaterSystemNEWEASmallCommunitySeminar

7/15/16

AmyLowellTownofFalmouthWastewaterSuperintendent

Outline

• Background/Planning/PermiIng• Design• ConstrucKon• Costs• OperaKon•  Lowflowchallenges• Performance

NewSilverBeach(NSB)AreaBackground

• Seasonalcommunitydevelopedaroundamarsh,nexttothebeach

• ARerextremestormevent,BoardofHealthdeclaredahealthemergencyduetosepKcsystem/cesspoolissues

• BoardofHealthbegantheprocessofplanningasewersystem

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ProjectAlternaKvesIndividualonsitetreatmentsystems•  Smalllots,insufficientdepthtogroundwater.66properKeswouldneedhighmoundwithconcreteretainingwall

TightTanks•  EsKmateneedpumpoutevery8daysinsummer(if2000gall)SeveralTreatmentPlantSites•  Severalsitesfellthrough-unwillingsellersorotherdeadendsPumptoMainWWTF• Wouldhaverequired~4.2mileforcemainand2liRstaKons• Consideredlaterinprocess–wouldhaveneedednewpermiIng,addiKonalKme,loseloan,etc

PermiIngHistory• 3permits,allappealed

• Wetlandpermitfortreatmentplant• WetlandpermitforcollecKonsystem• Groundwaterdischargepermit

• TownulKmatelyprevailed• Processtookmanyyears–bidprojecttwice

Design

•  ServiceArea:~220singlefamilyresidenKalhomesinNSBarea+NorthFalmouthElementarySchool

• OneliRstaKon,2smallgrinderpumpstaKonsserving3-5homes(municipal,locatedwithinroadrightofway)

•  ~2milesofgravitymain,~1mileofFM• WWTF•  EffluenttoinfiltraKonbedsbeneathschoolsoccerfield(byproject)

Design (Con,nued)

• DesignFlows–basedonTitleVfactors•  40,000gpdpeakflowfromservicearea+15,000peakflowschool=55,000gpd.Roundedupto60,000gpdtotal.

• DischargePermitLimits:•  TotalSuspendedSolids=30mg/L• BiochemicalOxygenDemand=30mg/L•  TotalNitrogen(andnitrate)=10mg/L

Construc,on

•  Took~1yeartocomplete• MainconstrucKonchallenges:Dewatering,exisKnguKliKesinpoorcondiKonandlocaKonsnotwellrecorded,bulkhead,smallWWTFsiteadjacenttowetlandsattheendofaresidenKalstreet

•  Startedup2009

WWTF Site Before Construc,on

WWTF Near Comple,on

Li? Sta,on

Shared municipal grinder pump – before and a?er modifica,on

Project Appropria,on and Borrowing

Year Amount Appropriated 1997 $3,567,000 2002 $1,200,000 2006 $7,733,000

$12,500,000

Borrowed Bonded Total $1,650,000 SRF Loan Total – DEP held 0% $7,775,000

Total: $9,425,000

Cost Appor,onment

TotalFinalProjectCostforBejerment $9,103,055.82

PaidByPropertyOwners-Bejerments(70%) $6,372,139.07

PaidByTown(30%) $2,730,916.74

NumberofAssessedProperKes 231

BejermentCostPerProperty $27,585.02

Opera,on

• Processflow–FineScreen,InfluentEqualizaKonTank,WetWell,SequencingBatchReactors,EffluentEQTank,[UV–notrequiredyet]

•  SequencingBatchReactors–Fluidyne•  ChangedfromKme-basedcontroltodissolvedoxygencontrolaRerstartup–withfluctuaKnginfluentflowverydifficulttogetconsistentperformanceusingKme-basedcontrol

• Nosludgehandlingonsite.Removesludgeasnecessary,trucktomainWWTFforthickening/disposal.

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NSBWWTFEffluentFlowOverthePast~5Years(gpdx1000)

Low Flow Challenges

•  LowflowmeansmorevariableinfluentconcentraKons•  IndividualdischargersandeventscanhaveasignificantimpactontheWWTF,especiallyduringlowflowperiods–ex:schoolfloorcleaning

•  SeasonalflowchangesrequireseasonaloperaKonaladjustments–tanksetpointlevels,cycleKmes,etc

•  Seasonalriseandfallisnotsteady–alsofluctuatesdaytoday•  TimeforO&MisnotproporKonaltoflow• Plantperformance/dischargepermitcangetasmuchajenKonfromregulatorsandothersashigherflowpermit(ajenKonalsonotproporKonaltoflow)

• Despitechallenges,WWTFhasgenerallyperformedquitewell

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NSBWWTFInfluentandEffluentBiochemicalOxygenDemandOverthePast~5Years(mg/L)

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NSBWWTF-CumulaMveInfluentandEffluentNitrogenLoad(lbs)

OverthePast5YearsCumulaKveInfTNLoad CumulaKveEffTNLoad

Ques,ons?