wastewater treatment - thatchers cider - uk… · wastewater treatment. case study. thatchers cider...
TRANSCRIPT
BiOWiSH™ Aqua Benefits
• Reducessludgeproductionandhandling
• Increasesplantcapacitybyreducingcontacttime
• Eliminatesodorousemissions
• Deliverssubstantialenergysavingsduetoreducedaeration
• Minimizesneedforchemicaladditives
• Stabilizesandimprovesplanttreatmentperformance
• Lowershydrogensulphide,ammoniaandnitratelevels
• Pre-treatsinfluentincollectionsystems
• 100%naturalandnon-toxic
Available Sizes
• 100g/3.5oz
• 1kg/2.2lb
Wastewater Treatment
Case Study
Thatchers Cider Company Ltd, United Kingdom
Background
ThatchersCiderCompanyLtdisamanufacturerofciderandfruitjuicessituatedinthecountyofSomerset,UKwithanestimatedannual(cider)productionofaround28millionlitres.Effluentfromciderandjuiceproductionistreatedataseparatesitesituatedhalfamilefromthefactory.Theeffluentispumpedthroughaprivate4inchmaintothe11acretreatmentsite.
TheschematicofeffluenttreatmentisshowninFigure1.TreatedeffluentispumpedintothepublicsewerfortreatmentanddisposalatWeston-super-Maremunicipalsewagetreatmentworks.
Figure 1. Schematic of Effluent System
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Lagoon 1: primary lagoon
Lagoon 2: storage lagoon
Lagoon 3: primary aeration lagoon
Lagoon 4: secondary aeration lagoon
Lagoon 5: final effluent lagoon
Biological Help for the Human Race™
Biological Help for the Human Race™
Productionatthefactoryisdividedintotwokeyparts.
1. Theon-goingmanufactureofciderfromapplejuice;thistakesplaceallyearround
2. Theprocessingoffruittoproduceciderandotherproductssuchasblackcurrantjuice;thistakesplacefromJulytoDecember
Bothoftheseprocessesproduceeffluentresultingfromthewashingandcleaningofprocessequipment,fruitandproductpackaging.
Theorganicstrengthofeffluentproducedduringthemanufactureofciderisapproximatelydoublethatoftheeffluentproducedduringfruitprocessing.Fruitprocessingusesevaporatorstoreducethevolumeofthejuiceforlongtermstorage;theresultingeffluentisdilutedbylargevolumesofcondensateandissignificantlyweakerinstrength.
Effluentfromthevariousproductionprocessesaredischargedviathefactorydrainagesystemintoalargesump.Itisthenpumpedtothetreatmentsiteusingaseriesoffloatstoregulatetheflow.
AsaresultoftheseasonalnatureofThatchers’ciderprocessing,theeffluentdischargedfromthesetwoproductionregimesrequireatreatmentsystemthatcanaccomodatealargevariationinflowandload.
Objectives
ThetwomainenvironmentalobjectivesofThatchers’were:
• Odorcontrol
• Sludgereduction
Thetreatmentsitecontainsalargevolumeofstoreduntreatedeffluent.Thiscreatesstrongodors,especiallyduringwarmweather.Theeliminationoftheseodorsisahighpriority.
Theremovalanddisposalofwastesludgeisexpensive,typically£250/tanker(US$410/tanker),withuptofourloadsaweekduringthehighseason.ThatcherswereobviouslykeentoreducethesecostsandtheydecidedtotrialBiOWiSH™ AquaforaninitialperiodofsixweeksbeginninginMay.
Results
Odor Reduction
BiOWiSH™hasreducedtheodoremanatingfromtheprimarylagoon.Theinstallationoftheaeratorwasbeneficialandaideddistributionofthebiocatalysts.Duringpeakflows,odorfromthestoragelagoonhadalsodiminished.However,asproductiondecreasedandthefactorydischargedeclined,thespilloverofeffluentfromtheprimarytothestoragelagoonreducedtoalowdailyvolume(328m3insummerto123m3inwinter).Thisresultedinanincreaseinodorbecauseinsufficientbiocatalystswerebeingtransferredtothestoragelagoonduringlowflowconditions.Tocounterthisoutcome,BiOWiSH™dosingwasmodifiedsothat1kgwasdividedequallybetweenthethreelagoons.Theodoremanatingfromthestoragelagoonhassinceimproved.
Biological Help for the Human Race™
Sludge Reduction
TheapplicationofBiOWiSH™hasbeenhighlysuccessfulinbreakingdownorganicmatter,therebyreducingsludge.Thisoutcomehasbeenobservedintheprimaryandaerationlagoons.
PriortotheapplicationofBiOWiSH™,thesludgelevelintheprimarylagoonwas0.4mabovethebase,amajorsourceofodorandsepticity.Throughouttheapplicationperiod,dipsweretakenandsludgelevelsmeasured.InJanuary,thesludgelevelwasmeasuredat0.15mabovebase.
Thereductioninmixedliquorsolidsintheprimaryaerationlagooncanbemeasuredbythevolumeofsludgesettlingintheclarifiers.Onaverage,throughouttheBiOWiSH™applicationperiod,75%ofsettledsludgehasbeeneliminated.Thesludgereductionisalsodepictedbythenumberoftankerloadstakenoff-sitefromThatchersasshowninFigures2and3.Theremaining25%ofsettledsludgeisnowreturnedtotheaerationlagoontomaintainthebiomass.
Increase in Biological Capacity
AlthoughgeneraleffluentqualityhasremainedstaticafterusingBiOWiSH™,thebiologicalloadingtotheaerationlagoonshasbeenincreased.ThiswasparticularlynoticeableduringearlyNovemberwhentheeffluentstrengthinthestoragelagoonexceeded7000mg/landthetemperaturewaslow.Atthistime,flowtotreatmentwasrunningat173m3/day,equatingto1211kgCOD/day.Duringthewinter,evenwithmixedliquortemperatureat3.50C,biologicalactivitywastakingplacealbeitatalowerflowrateof123m3/day.
Improvement in Process Stability
TheadditionofBiOWiSH™hasimprovedthestabilityofthebiologicalprocessintheprimaryaerationlagoon.Overweekendswithnooperationalinput,thequalityoftheeffluentremainssteady.Itisalsonoticeableafterovernightpowercuts,thattheprocessquicklyreturnstonormaloncepowerisreinstated.Thebiologicalprocessisnowabletoadapttoshockloadingwithoutnegativeimpact–thisresultisnoticeablewhenexcessivesludgeisreturnedtothesystemfollowingtheweekend.
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Figure 2. Reduction in Solids using BiOWiSH™ Figure 3. Reduction in Solids using BiOWiSH™
Biological Help for the Human Race™
Removal of Algal Bloom
Throughoutthisexercise,includingthetrialperiod,littlehasbeenstatedregardingtheoverallperformanceofthetreatmentprocesses,particularly,thefinaleffluentquality.ThereasonisthatBiOWiSH™hashadlittleimpactontheeffluentqualitydownstreamoftheclarifiers.ThequalityremainswellwithinconsentlimitsasitwaspriortoBiOWiSH™dosing.ThatcherseffluenttreatmentplantperformanceisasshowninFigure4.
Thereis,however,onenotabledifference:theremovalofalgalbloom.Thealgaedevelopsinthefinallagoonduringthesummer,wheneffluentqualityisgood,especiallyafterseveraldaysofstrongsunlight.Asaresult,theeffluentmaydoubleinstrengthandhasasignificantimpactontradeeffluentcharges.ThealgalbloomwasabsentduringtheBiOWiSH™dosingperiod.
Conclusions
Insummary,thetwokeyreasonsfortriallingBiOWiSH™ Aquawasthepotentialtoeliminateodorandtoreducesludgeproduction.Bothobjectiveshavebeenbroadlyachieved.Sludgereduction(75%),hasbeenhighlysuccessful,asdemonstratedbythefallintankerreceipts.
OtherbenefitsassociatedwithBiOWiSH™areabonus,namely,processstabilityandtheremovalofalgaefromthefinaleffluentlagoon.
ThemaincostfactorassociatedwiththedosingofBiOWiSH™isthecomparisonoftheannualcostoftheproductandthecostofremovingsurplussludge.DuringtheBiOWiSH™trial,thevolumeofsurplussludgeremovedoff-sitewas25%ofthevolumenormallyexpected.ThisvalueislikelytodecreaseasexperienceisgainedusingBiOWiSH™andthebiocatalystsreachtheirfullpotentialthroughthesystem.
SincethetrialbeganinMay,ThatchershasbeenusingBiOWiSH™foreightmonths.Muchoftheearlypartoftheprogrammehasrequiredchangestothestartermake-up,dosingschedule,distributionoftheproduct,thedailysludgereturnandageneraladaptationtothenewprocess(refertothesucceedingsectionformoredetails).ThefullevaluationofhowBiOWiSH™reactstothetreatmentprocessisstillongoing.
Figure 4. Effluent Treatment Plant Performance
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Biological Help for the Human Race™
TheThatcherslagoonsystemisamajorfactorwhenanalysingthecostofdosingBiOWiSH™.Thelargevolumeofuntreatedeffluentintheprimaryandstoragelagoonsassimilatedallshockdosesandrequiredconsiderablymoreproductthancomparedwithaconventional24hrbalancedsystem.However,oncestabilised,alowerdaily‘workingconcentration’of1kgwasshowntobeeffective.Onthisbasis,comparativecostsmaybederived.
• AnnualcostofsurplussludgedisposalwithouttreatmentwithBiOWiSH™ Aqua:65tankers/annum@£250/tanker=£16250(US$26650)
• AnnualcostofBiOWiSH™ Aquaat£60/kg@6kg/week=£18720(US$31200).AnnualcostofsurplussludgedisposalwithBiOWiSH™dosing=£3000(US$4900).Totalannualcost=£21720(US$35500).
Therewasnosignificantimprovementinthequalityofthefinaleffluent.Therefore,noreductionintradeeffluentchargescouldbeattributedtoBiOWiSH™dosing.However,theeliminationofalgaefromthefinaleffluentlagoonsavedtheannualcostofpurchasing4kgofgeneralpurposebacteria(£350)(US$570).
ThefiguresaboveshowthattheannualcostusingBiOWiSH™ Aquaismoreexpensivethanthepreviousconventionalmethodofeffluenttreatment.Theextracostis£5120/annum(US$8350).Thisincreaseshouldbeconsideredasthecostofeliminatingodorsfromthesite,amajorenvironmentalfactorassociatedwitheffluenttreatmentandafundamentalobjectiveofThatchersCider.
Implementation Program
Thatchers’effluenttreatmentprocessisunusualbecauseofthelargevolumeofstoragecapacity.Whenfull,thestoragelagooncontainsaverylargeorganicloadand,unlikeanormaldaytodaydischarge,theBiOWiSH™dosingscheduleshouldreflectthiscondition.Onthisbasisitwasdecidedtoshockdosetheprimaryandstoragelagoonswiththeproductonadiminishingscaleandaddadailydoseof2mg/ltotheprimarylagoon.Theassumptionwasthatthebiocatalyticactivitywouldtransferthroughtotheprimaryaerationlagoonandtheremainingprocesses.Organicstrengthinthestoragelagoonatthistimewas4100mg/lCODwithaflowratetotheaerationlagoonof328m3/day.
TheBiOWiSH™starterwasmixedwithwateratbetween5g/land10g/landthetemperaturemaintainedabove150C.Thestarterwasdistributedatvariouspointsaroundtheperimeterofthelagoonstoaidmixing.
ThisinitialtrialwhichbeganinMaywasonlypartiallysuccessful.Theodorwassomewhatreducedandthemixedliquorqualityintheaerationlagoonimproved,resultinginanincreaseinpHfrom7.9to8.1understableconditions.However,nonoticeablechangewasobservedinthevolumeofsludgeproduced.Afterconsideration,thelowstart-upmixturetemperature,theinsufficiencyofdaytodaydosingandtheincorrectdosinglocationwerethefactorsthatcontributedtothisoutcome.
However,itsoonbecameapparentthattheshockloadingofBiOWiSH™hadbeenassimilatedbythelargemassoforganicmattercontainedinthetwolagoons–theprimarylagooncontainedsludgethatwasapproximately0.5mindepth;hence,insufficientBiOWiSH™activitywasreachingtheaerationprocessdespitedosingatanestablishedrateof2mg/l.
Withtheendofthetrialapproachingadecisionwasmade,basedontheexperiencegained,tocontinuewithBiOWiSH™.Thedosingregimewasamendedsothattheproductwouldbesharedbetweentheprimarylagoonandtheprimaryaerationlagoon.ItwasconsideredthatBiOWiSH™wouldbe,initially,farmoreeffectiveinreducingsludgeifitweredoseddirectlyintothebiologicalprocess.Continuationwithdosingatthefrontendasbeforewouldalsocontroltheodorissue.
Theseassumptionsturnedouttobebroadlycorrect,andwiththeknowledgethatdosingwasrelatedtoloadandnotflow,theaerationprocesswastransformed.ThiswasinAugustwhenThatchershighseason’sproductionhadbeenrunningforaboutamonth.
Withinfourdaysofdosingintotheaerationlagoon,thevolumeofmixedliquorbegantoreduce;thiswasnoticeablewhenemptyingtheclarifiers.Settleabilityofthesludgeimproved,producingadensersludgeandaclearerinterfacebetweensludgeandliquid.ThepHofthemixedliquorsteadiedat8.2to8.3,andthegeneralstabilityoftheprocessimproved,allowinganincreaseinbiologicalloadingwithoutdetriment.
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BiOWiSH™dosing,atthisstage,was1kg/dayintheprimarylagoonand500g/dayintheprimaryaerationlagoon.Thehighdosingoftheprimarylagoonwascontinuedbecauseoftheanaerobicconditions.Considerableactivitywasrequiredtoreducethevolumeofsludgeandkeeptheodorundercontrol.
Aftertwoweeks,thevolumeofsludgeintheclarifiersreducedby75%.Mostofthesludgewasreturnedtotheaerationlagoontomaximisebiologicalactivity.
Thedosingschedulecontinuedthroughouttheseasonwhenproductionchangedfromblackcurranttoappleprocessing.Theeffluentfromappleprocessingexertsgreaterorganicloadingsandcanbeproblematictotreat.However,thebiologicalactivityintheaerationlagoonwassustainedintheearlystageswithpHholdingupataflowrateof328m3/dayandCODof4750mg/l.Asexpected,withtheseasonprogressing,theambienttemperaturestarteddroppingandbymid-Octobertheraweffluentstrengthintheprimarylagoonincreasedto10000mg/l.Theeffluentfeedtotheaerationlagoonincreasedto5750mg/l.AtthisstagedistributionofBiOWiSH™intheprimarylagoonwasconsideredinadequate,soasmall1.5kwsurfaceaeratorwasinstalled.Theaimwastoimprovemixingandminimisesepticity.
ByearlyNovember,organicstrengthinthestoragelagoonhadincreasedto7000mg/lrequiringtheflowratetotheaerationlagoontobereducedto172m3/day.
ThedecisionwastakentoreduceBiOWiSH™dosingbecauseofthelongtermcostvstreatmentfactors.Thedosingwasreducedto1kg/dsharedequallybetweentheprimaryandaerationlagoon.
Afurtherreductionintheflowratetotheaerationlagoonwasrequired(to144m3/day)becauseofthedecliningambienttemperatureandtheconsequentreductioninactivity–droppingpHlevels,increasingCODconcentrationsandpoorersludgesettlementallindicatingthefalloffineffluentquality.
DuringmuchofDecember,ambienttemperaturesremainedbelow00C,causingbiologicalactivitytofurtherdecline.Organicstrengthofthestoragelagoonpeakedat7750mg/landflowtotreatmentwasreducedto123m3/d.However,effluentstrengthintheprimarylagoonhaddecreasedfrom10000mg/lto7000mg/lasaresultoftheimproveddistribution(aerator)ofBiOWiSH™andthereductioninraweffluentflowfromthefactory.
ThroughoutJanuary,effluenttreatmenthasremainedsteadywithallsludgereturnedtotheaerationlagoonandfinaleffluentqualitywithinconsentlimits.
Duringthewintermonths,theBiOWiSH™startersolutionwasheatedtobetween200and250Candthedosingmaintainedatarateof1kg/day.
Contacts
BiOWiSH Technologies
Email:[email protected]
Adrian Cook
Simply Environmental
M:+447818553234
T:+441275871103
W:www.simplyenvironmental.co.uk
CSWT26JU11INT
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