BiosolidsStabiliza-oninConcord,NewHampshire–Sowheredowe

gofromhere?

Presentedby:ChrisDwinal,PE

•  HistoryofbiosolidsinConcord

•  CurrentRDPlimestabiliza-onsystem

•  2015BiosolidsStabiliza-onEvalua-on

•  Short-termplan

•  Long-termrecommenda-ons

•  Keyfactorsinul-matepathforward

1999 2002

2005 2010 2014 2015 Pre-1999

-  Plate and frame press -  Class B lime stabilization -  Land spreading through RMI

First Biosolids Study recommends belt filter presses

and RDP Class A lime stabilization

Dewatering and RDP Upgrade Complete

Biosolids Stabilization

study recommends RDP

short term, ATAD/TPAD long

term

Comprehensive WWTF Evaluation

recommends THAD and RDP

evaluation

2003 2016

Multiple studies/upgrades to address process issues and fugitive odors and lime dust

RDP Upgrade Underway

•  Difficultymee-ngClassAwithvaryingsludge

•  Ineffec-vemixingoflimeandbiosolids

•  Fugi-vedust/odoremissions

•  Ledtoven-la-on,odorcontrol,andconveyor/mixingupgrades2008-2010

•  Systemfinallyrunningwellforpast5years,buts-llnotideal…

•  ClassAandBlimestabiliza-on

•  Compos-ng

•  Thermaldrying

•  ATAD

•  Incinera-on

•  Landfill

•  Anaerobicdiges-on–mesophilic,thermophilic,thermalhydrolysis

•  Oneofseveralcompletedsince1999•  Goals

§  Conductcomprehensiveevalua-onofcondi-onandlifeexpectancyofRDPsystem◗  Recommendedin2014ComprehensiveEvalua-on◗  CityhascontractwithRMIthrough2021fortruckingandreuseofClassAlimestabilizedsolids($29.10/wetton)

§  Conductacomprehensivereviewofallbiosolidsprocessingandreuseop-onsavailabletoConcord◗  NHDESrecommenda-on

•  Greatshapefor12yrs.ofservice

•  Allequipments-llfunc-oning

•  Augerheatersareweakpoint

•  SomedamagetoThermoblender

•  Limedust/ammoniaemissionsinprocessingroomandgaragenotacceptabletoCitymovingforward

•  Severalupgradeop-onsconsidered

Compos-ng

ClassAlimestabiliza-on

Anaerobicandaerobicdiges-on

Drying–mechanicalandsolargreenhouse

Incinera-on

Gasifica-on

Carboniza-on

DewateredBiosolidstooff-siteprocessing

DemonstratedTechnology

ScalabletoConcord’sneeds

Poten-alforoff-siteodors

Endmarketforprocessedbiosolids

Possibilityofpublic-privatepartnership

•  Notdemonstrated

§  Carboniza-on,gasifica-onandthermalhydrolysis

•  Notscalable

§  Incinera-on

•  Odorpoten-altoohigh

§  Compos-ngandsolargreenhousedrying

•  Landfilling

•  Public-privatepartnership

§  S-gmaofbeingdumpinggroundfortheregion

§  Concernswithodors–historicalissuesinConcord

•  3ClassALimeStabiliza-on§  RetainRDPlong-term§  SchwingBioset§  FKCscrewpress

•  3Diges-on§  TemperatureorTwoPhaseAnaerobicDiges-on§  MesophilicAnaerobicDiges-onwithDrying§  AutothermalThermophilicAerobicDiges-on

GoodIndoorAirQuality

ProcessStabilityand

Control

Simpleandoperateandmaintainin8-hourshie

MinimalrecycleloadstoWWTF

Poten-alforenergyrecovery

Endproductquan-tyand

quality

•  RDP•  SchwingBioset•  FKCScrewPress

PROS CONS

Noenergyrecovery

Full--mestaffingrequired

Poorprocesscontrol/stability

Poorairquality

Limitedrecycleloadsimpact

Nopostprocessingrequired

Stackable,dryendproduct

Simpletooperate

OdorswhenspreadingVerycosteffec-ve-exis-ng

50U.S.installa-onsCalciumsatura-onissues

Highestbiosolidsquan-ty

PROS CONS

Calciumsatura-onissues

Requirespostprocessing

Poorendproductquality

Noenergyrecovery

Simpletooperate

Limitedstaffingrequired

Goodprocesscontrol/stability

Fullyenclosedgoodairquality

Highbiosolidsquan-ty

30U.S.installa-ons

Limitedrecycleloads

PROS CONS

24/7opera-on

Highbiosolidsquan-ty

Calciumsatura-onissues

Noenergyrecovery

Limitedrecycleloads

Simpletooperate

Goodprocesscontrol/stability

Goodairquality

3U.S.installa-ons

CONS

Highrecycleloads

Complexprocessx2

24/7opera-on

PROS

Excellentbiosolidsquality

Goodenergyrecovery

Goodprocesscontrol/stability

Fullyenclosedgoodqualityair

30U.S.installa-ons

Lowestbiosolidsquan-ty

CONS

HighestrecycleloadstoWWTF

Complexprocess

Numerousinterna-onalinstalla-ons,butonly4U.S.

PROS

Highestenergyrecovery

8-hourstaffingduetoautoma-on

Goodprocesscontrol/stability

Fullyenclosed,goodairquality

Excellentbiosolidsquality

Lowestbiosolidsquan-ty

CONS

Noenergyrecovery

Moderatelycomplexprocess

PROS

Excellentbiosolidsquality

8-hourstaffingduetoautoma-on

Goodprocesscontrol/stability

Fullyenclosed,goodairquality

Lowbiosolidsquan-ty

LowrecycleloadstoWWTF

40U.S.installa-ons

•  MADdroppedduetocomplexityand24/7

•  TPAD/2PADandATADcarriedforth

•  Both~$20millioncapitalcost•  TPADlowerlife-cyclecostduetolowerenergyrequirements

•  Splitdecision§  StaffmorecomfortablewithATADandmoreinstalls§  TPAD/2PADlowerlifecyclecost(electric)butfarlessinstalls

•  Verycosteffec-ve,25%thecostofdiges-on•  But,notdesirablelongterm

§  Highestbiosolidsquan-ty,lowestbiosolidsquality§  Nopoten-alforenergyrecovery§  Higheroperatoralen-onrequired§  Concernswithairquality

•  However,goodshorttermop-on§  UpgradeRDPandven-la-on-~$2million§  Lowcost-ppingfeeinplacethrough2021

•  Someformofdiges-on–consistentwith2006and2014studies

•  TPAD/2PADlowestlifecyclecosts,but•  CitystaffpreferATAD

§  Familiaritywithequipment§  ManymoreU.S.installs§  ConcordWWTFtypicalsizeofATADinstalls

•  So,what’snext?

•  TPAD/2PADlife-cyclecosts-llcheaperwithlowerelectricitycost§  capitalcostofTPAD/2PADlowerthanATAD

•  UpgradingRDPallows-mefor…§  furtheradvancementofTPAD/2PADtechnology§  AllowformoreU.S.installs§  preliminarydesignstonailcosts§  Possibledevelopmentofalterna-vepowersourcestostabilizeelectricityrates?

§  Possiblemerchantfacilityforoffsiteprocessing?

•  Overpasttwoyears§  Highof$0.147/kWh§  Lowof$0.112/kWh§  Averageof$0.132/kWh

•  NewsolarPVincornfieldnexttoWWTF§  20yearfixedpriceof$0.086/kWhjustforsupply§  Essen-allyequaltocurrentsupplypriceforWWTF§  WilloffsetotherhigherpriceelectricityusersinConcord

Ques-ons?