Sustainable airport environments : a review of water conservation practices in airports.

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ContentslistsavailableatSciVerseScienceDirect

Resources,

Conservation

and

Recycling

j o u r n a l ho me p ag e :w w w . e l s e v i e r . c o m / l o c a t e / r e s c o n r e c

Review

Sustainable

airport

environments:

A

review

of

water

conservation

practices

in

airports

Isabella

de

Castro

Carvalho

∗

,

Maria

Lúcia

Calijuri,

Paula

Peixoto

Assemany,

Marcos

Dornelas

Freitas

Machado

e

Silva,

Ronan

Fernandes

Moreira

Neto,

Aníbal

da

Fonseca

Santiago,

Mauro

Henrique

Batalha

de

Souza

FederalUniversityofVic¸osa,DepartmentofCivilEngineering,EnvironmentalResearchGroup,P.H.Rolfs,s/n,CampusUniversitário,Vic¸osa,MG36570-000,Brazil

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received30October2012

Receivedinrevisedform19February2013 Accepted20February2013

Keywords: Airport

Waterconsumption Efﬁcientwateruse Rainwater Wastewaterreuse

a

b

s

t

r

a

c

t

Airportsconsumesignificantamountsofwatertomaintaintheirinfrastructure.Giventheincreasing worldwidedemandforthistypeoftransportandthecurrentsituationofwaterscarcityinmanyregions oftheplanet,effortsshouldbemadetoassesswaterconsumptionprofilesaswellasalternativesfor itsefficientuse.Inairportcomplexes,mostofthewaterisusedtomeetnon-potabledemands,making thempotentialenvironmentsforimplementingconservationpracticesaimedatreducingthesedemands –suchaswatermeteringandinstallationofwatersavingfixtures–andalsoforsearchingforalternative sources,suchasrainwaterandtreatedgreywaterordomesticsewageeffluent.Thisreviewpresents informationregardingwaterconsumptioningloballyimportantairportsinordertoprovideabasisfor studiesthatguidepoliciesanddecision-makingtowardasustainablemanagementoftheseenvironments duringtheplanningandexecutionofconstruction,expansionandmodernizationprojects.

Contents

1. Introduction... 28

2. Waterconsumptioninlargeairports... 28

3. WaterconsumptioninBrazil... 30

4. Mainattitudesrelatedtotheefﬁcientuseofwater:experienceofmajorairports... 31

4.1. Waterconsumptionmetering... 31

4.2. Watersavingsanitaryﬁxtures... 32

4.3. Waterreuse... 32

4.3.1. Rainwateruse... 32

4.3.2. Greywaterreuse... 33

4.3.3. Seawaterreuse ... 34

4.3.4. Sewageefﬂuentreuse... 34

4.4. Othermeasures... 34

4.4.1. Landscapemanagement... 34

4.4.2. Airconditioningsystems... 34

5. Finalconsiderations... 35

References ... 35

∗ Correspondingauthor.Tel.:+553138993098;fax:+553138993093.

E-mailaddresses:isakpi@yahoo.com.br,isaccarvalho@hotmail.com(I.C.Carvalho),calijuri@ufv.br(M.L.Calijuri),paulaassemany@hotmail.com(P.P.Assemany), marcosdornelases@yahoo.com.br(M.D.F.M.e.Silva),r9neto@yahoo.com.br(R.F.MoreiraNeto),anibalsantiago@gmail.com(A.F.Santiago),mauro.batalha@ufv.br (M.H.B.deSouza).

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1. Introduction

Thehighdemandfordrinkingwaterresultingfrompopulation increase,droughtsandunpredictableclimaticpatternsis becom-inganalarmingrealityinmanypartsoftheworld(Batesetal., 2008;WiekandLarson,2012).Increasingconcernsregardingthe consequencesofclimatechangealsoemphasizetheneedforwater resourcesmanagementplanninginordertoguaranteethatcurrent andfuturedemandswillbemettothedesiredlevelof satisfac-tion(BabelandShinde,2011;Iglesiasetal.,2011;Quevauviller, 2011;Schlüteret al.,2010).Withinthis context,theconceptof “waterconservation”involvesthecontrolledandefﬁcientuseof thisresourceaswellasreusemeasures.Conservingwaterimplies actingin asystemic mannerin themanagementof supply and demand(Brooks,2006;HespanholandGonc¸alves,2004).

Urban water management efforts are usually focused on demand policiesthat tryto encourage the rational useof this resourceinordertoreducelossesand waste.Demand manage-mentisoneofthemostrelevantissuesworldwide(Arbuésetal., 2010;Fadlelmawla,2009;ZhongandMol,2010),focusingon reduc-ingconsumptionrelatedtowaterend-usesby,forinstance,using water-savingsanitary fixtures.Theobjectiveis tominimizethe needforwatersupplyandsewagetreatment,bothofwhichare associatedwithhighcostsandcanbeenvironmentallyandsocially detrimental(Willisetal.,2011).Supplymanagementisrelatedto thesearchforalternativewatersourcessuchasreuseofrainwater, wastewaterandgreywater,amongothers(GhisiandFerreira,2007; Hurlimann,2011;KahindaandTaigbenu,2011;Ryanetal.,2009). Airportsarepotentialenvironmentsforimplementingpolicies andtechnologiesaimedatconservingwaterbecauseoftheirlarge consumption,mostlyfornon-potablepurposessuchaswater cool-ingsystems,firecontrol,cleaningandwashingofvehicles,runways andaircrafts(MoreiraNetoetal.,2012).Worldwide,manyairports areemployinginitiativestopromotetheefficientuseofwater(ADR, 2009;FraportAG,2010;HKIA,2011;MAG,2007;NIAC,2011;SYD, 2009a,2009b).However,thosewhichimplementthisconceptmost stronglyareusuallythose thatarefacingwaterscarcity. Bolder alternatives,suchaswastewaterreuseandrainwaterusefortoilet flushing,bothofwhichneedgreaterinterventioninairport infra-structure,areusuallyimplementedonlyintheconstructionofnew terminalsorinscarcitysituations.

Themain purposesof this review aretocollectinformation regardingwater consumptionin airport complexesand present theconservationpracticesthat theycurrentlyadopt,aswellas informationpertinenttothefuturedevelopmentofpoliciesand programswhich aimatusingwaterrationallyinthese environ-ments.

2. Waterconsumptioninlargeairports

AccordingtotheAirportsCouncilInternational(ACI,2011),the numberof passengersregisteredin2010in 1318airportsfrom

157countriessurpassedthefivebillionmarkforthefirsttime,an increaseof6.6%comparedto2009.Globaldomestictrafficjumped by5.8%whileinternationaltrafficincreasedby7.7%.Aircargotraffic alsohitarecord:atotalof91milliontonswith15%growth com-paredto2009.Table1showsthenumberofpassengersbyregion in2010andthepercentageofvariationrelatedto2009.

Followingthetrendsbyregion,wecanobservethatthe emerg-ingmarketsledthegrowth.TheLatinAmerica-Caribbeanregion, supportedbysubstantialdevelopmentinBrazil,presentedwitha 13.2%increaseover2009.TheMiddleEastandAsia-Paciﬁcregions alsopresentedsigniﬁcantgrowth.Thelowestpercentageswere observed for the mature marketsof North America (2.5%) and Europe(4.3%).

Theseﬁgureshighlighttheurgencyoffacingtheairportcapacity challenge.Airportoperatorsworldwidearefocusingontheneedto providethepassengerapositive,seamlesstravelexperience,andon planningnewcapacitytomeettheexpecteddoublingofpassengers inthenext15–20years.Morethanever,governmentsandairline partnerswillneedtoworkcloselywithairportstoensurethatthe requiredcapacityisaddedinasafe,secure,efﬁcientandsustainable manner(ACI,2011).

Table2presents thepassengertrafﬁc dataforthemain air-ports in the world, as well as the population equivalent (PE) fortheseenterprisesintermsofwaterconsumption.Datawere extractedfromtheannualreports providedbytheoperatorsof theseairportsand,inordertocalculatethePE,aconsumptionof 200L/(personday)andonlythetotalamountofpotablewaterused intheairportwereconsidered.

ThefirsttenairportslistedinTable2wereamongthe30largest intermsofpassengertrafficin2010(ACI,2011).Theotherairports alsohadsignificantpassengertrafficin2010but,mostimportantly, theyprovideannualdataregardingtheiroperationsaswellassocial andenvironmentalresponsibilityactions.

These airports,suchas theParis-CDG, presented, in2010, a waterconsumptionequivalenttothatofcitieswithapopulation of31thousandpeople,providinganexampleofthegreatamount ofwaternecessaryfortheseairportstomaintaintheiractivities. PassengertrafﬁcintheAtlantaInternationalAirport,in2010, sur-passed89millionbuttheairportconsumedanamountofwater equivalenttoacityof13thousandpeople,possiblyasaresultof itsgreatereffortinrationalizingitsuseofwater.

Fig.1showstheannualwaterconsumptionofsomeofthemain airportsintheworld,aswellasthewaterconsumptionper passen-ger,calculatedbydividingthetotalpotablewaterconsumptionby thenumberofpassengerstransportedinthesameyear. Informa-tionregardingthenumberofpassengersandwaterconsumption wasobtainedfortheyear2010forallairports,exceptfor Fiumi-cinoinRome,whichpublisheditslatestenvironmentalreportin 2009.Theindex“L/passenger”wasusedinmany oftheairport annualreportsstudiedinordertoquicklyandsimplyorganizedata andenableconsumptiontobecomparedbetweenthem.However, itiswellknownthatwaterdemandisacomplexandnon-linear Table1

Airpassengerandaircargotrafﬁcin2010. RegionsdeﬁnedbyACI Noof

passengersa %ofchange comparedto2009 Total cargob %ofchange comparedto2009 Noof airports Africa 155,979,778 9.5 1,715,838 1.9 154 Asia-Paciﬁc 1,294,834,546 11.3 31,856,866 18.5 172 Europe 1,466,758,533 4.3 17,920,309 15.5 454 LatinAmerica-Caribbean 403,676,303 13.2 4,665,694 14.3 263 Middle-East 206,622,059 12.0 5,881,214 13.7 53 NorthAmerica 1,509,836,075 2.5 28,709,087 13.2 222 ACI 5,037,707,294 6.6 90,749,008 15.3 1318

AdaptedfromACI(2011).

a_Total_passengers:_total_passengers_enplaned_and_deplaned,_passengers_in_transit_counted_once. b _Total_cargo:_loaded_and_unloaded_freight_and_mail_in_metric_tons.

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Table2

Passengertrafﬁcinimportantairportsworldwideandpopulationequivalent(PE)oftheseenterprisesintermsofwaterconsumptionfor2010.

Airports Abr. Noofpassengers

(millions)

PE(thousand people)a

Reference

1 AtlantaInternationalAirport ATL 89.3 13.0 DOAAtlanta(2010)

2 London-HeathrowAirport LHR 65.9 25.4 LHR(2010)

3 Paris-CharlesdeGaulleAirport CDG 58.2 31.4 ADP(2010)

4 FrankfurtAirport FRA 53.0 12.4 FraportAG(2010)

5 Madrid-BarajasAirport MAD 49.8 15.8 MAD(2010)

6 AmsterdamAirport AMS 45.2 17.0 SchipholGroup(2011)

7 SanFranciscoAirport SFO 39.3 24.7 SFIA(2011)

8 Rome-FiumicinoAirport FCO 36.2 15.6 ADR(2009)

9 SydneyAirport SYD 36.0 14.2 SYD(2010)

10 MunichAirport MUC 34.7 13.1 MUC(2010)

11 NaritaAirport NRT 32.9 23.8 NIAC(2011)

12 TorontoAirport YYZ 31.8 12.7 GTAA(2010)

13 Paris-OrlyAirport ORY 25.2 6.55 ADP(2010)

14 ZurichAirport ZRH 22.9 7.27 ZIA(2010)

15 ManchesterAirport MAN 18.3 12.4 MAG(2011)

16 BrusselsAirport BRU 17.2 3.56 BAC(2010)

17 Portugal-LisbonAirport LIS 14.1 7.84 ANA(2010)

18 Portugal-PortoAirport OPO 5.27 1.25 ANA(2010)

a_Calculated_using_total_water_consumption_provided_by_the_airports_annual_{environmental}_reports_for_2010,_except_for_{Rome-Fiumicino,}_which_had_information_only_for

2009.

functionofclimatic,institutionalandmanagementvariables(Babel andShinde,2011).Thisindexwillthereforebeusedinthisreview, butnotwithouttakingintoaccountthatitisnecessaryto iden-tifythevariablesinsideanairportenvironmentthathaveagreater inﬂuenceonwaterconsumptionbeforeanystatementcanbemade regardingtheeffortsofairportsinimplementingwater conserva-tionpractices.

Majordifferencescanbehighlightedbetweentheamountsof waterconsumedintheairportsshowninFig.1.Airportswithlarge passengertrafficnumbers,suchastheairportsofAtlanta,Frankfurt andMadrid,showlowerconsumptionthanthosewithasmaller numberof passengers,suchasNarita, Rome-Fiumicinoand San Franciscoairports.Thisshowsthattherelationshipbetweenwater consumptionandthenumberofpassengersisnotalwaysdirect and proportional.Atlanta,despitehavingthehighest passenger traffic,isnotthelargestwaterconsumer,withanindexofonly 11L/passenger.Thisairporthasintegratedactionsfortheefficient useofwaterintoitspractices,suchastheadequatemanagement ofvegetatedareas,useofwatersavingsanitaryfixturesand air-coolingsystemsthatdonotusewatercoolingtowers.Lisbonand Manchesterairportshave alowertotal waterconsumption, but haveindicesof43and50L/passenger,respectively.Theairports ofFrankfurt,MadridandAmsterdamhavegreatertotalwater con-sumptionandpassengertraffic,butpresentindicesofonly22,24 and27L/passenger.FrankfurtandAmsterdamuserainwaterand

watersavingsanitaryfixtures,whereastheactionsofLisbonand Manchester towardtherationaluseof water arestill incipient. MadridAirport,however,despiteitslowconsumptionindex,has notimplementedanysignificantactionstoreduceconsumption, nordoesitusealternativewatersources,whichprovidesanother exampleofthefactthattheindex“L/passenger”doesnot necessar-ilyreflectconservationactionsorthebestmanagementofwater resourcesinaspecificairport.

Fig.2showssomeofthemainwatersourcesusedinairportsthat haveadoptedconservationpracticesandthatpresenttheresultsof theseinitiativesintheirannualreports.

AirportssuchasFiumicino,SydneyandFrankfurtare promi-nent because of the volume of recycled water they use, as is Naritaforitsuseofgreywater.However,mostairportshavenot integrated theimplementationofconservation measures.Some airportsacttoreducedemandmainlythroughthemanagement andmonitoringofconsumption,whereasothersfocustheiractions onthesearchforalternativewatersourcesinresponseto increas-ingdemands.Theobjectiveshouldbetointegratesuchmeasures givenwateravailabilitywillnotkeeppacewithairportexpansion ortheexpectedgrowthoverthenextyears.Itisalsoimportantto highlightthatmanycountrieshaveconsideredmethodologiesfor introducingtariffsforwater,previouslyconsideredafreeresource (Fadlelmawla,2009;Zhongand Mol,2010).AccordingtoZhong andMol(2010),waterpricingsystemssuchasthesehavemany

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Fig.2. Watersourcesinairports.

objectives:tocoverincreasingcosts,protectscarceresourcesand introduceaneconomicmotivationforpromotingtheefﬁcientuseof water.Airportsshouldadoptsuchreformsandconsiderwater con-servationmeasuresnotonlyasenvironmentallyresponsiblebut alsoasaneconomicadvantage.

3. WaterconsumptioninBrazil

According to the Brazilian Airport Infrastructure Enterprise (Infraero)10 ofthemostimportantairportsinBrazilaccounted for67%oftheairpassengertrafﬁcin2010.Together,theseairports consumedover3.5millioncubicmetersofwater,whichequals73% ofthetotalconsumption registeredforthe66Brazilianairports underInfraero’sadministration.

Figs.3and4showthatitisnotpossibletoconsidertheretobe anexplicitrelationshipbetweenthenumberofpassengers trans-portedandthewaterconsumptionineachrespectiveairport,either inBrazilorforinternationalairports.

Fig.3shows,forinstance,thatGaleãoAirport(GIG)represents 25%ofthetotalwaterconsumptionbutoccupiesfourthposition intermsofthenumberofpassengerstransported.AsforConﬁns Airport(CNF),theconsumptionof4.5%issimilartothatforthe airportsofBrasília(BSB)andCongonhas(CGH),at4.2and3.3%, respectively;however,thepassengermovementatConﬁnsin2010 washalfofthatoftheothertwoairports.

Fig.4showswaterconsumptionandtheindexoflitersper pas-sengerforthesame10airports.Ithighlightsthattheairportwith thegreatestpassengermovementdoesnotalwaysalsohavethe

largestconsumption.Inotherwords,fortheBrazilianaswellasfor theinternationalscenario,relatingwaterconsumptiontothe num-berofpassengerstransportedisnotasufficientmeasuretoassess theefficiencyofthewaterresourcemanagementmodelsusedbyan airport.Asmentionedearlierinthissection,Galeãooccupiesfourth positionintermsofnumberofpassengersbuthasthehighestvalue forL/passenger,immediatelyfollowedbyGuarulhosAirport(GRU). However,despitethesehighindices comparedtootherairports withsimilarlargepassengerthroughput,Galeãohasalready signif-icantlyreduceditswaterconsumptionafterimplementingsystems forreusingsewageeffluentandusingrainwatertomeetthewater demandsoftheairconditioningsystem.In2001,thisairport con-sumedabout150,000m3_of_water_per_month._In_2010,_despite_the

increaseof106%inthenumberofpassengerscomparedto2001, themonthlywaterconsumptionhadreducedto99,200m3_.

It isimportant tohighlightthat ahighindex ofL/passenger doesnotimplicatetheretobebadorinefficientmanagementof waterresources,becauseothercharacteristicsintrinsictoairport environments,suchascategory(internationalordomesticflights), numberofflightsandamountofcargotransported,amongothers, influencethepatternofwaterconsumptionandarenotrevealed fromtherelationshipbetweenconsumption andthenumberof passengers.However,thisrelationshipcanbeusedasaninitialstep inidentifyingexcessiveconsumptionandwherewater conserva-tionmeasuresarenecessary.

Airports witha similar annual passenger movement, in the rangeofﬁvetosixmillionpassengersperyear,suchastheairports ofPortoAlegre(POA),Salvador(SSA),Fortaleza(FOR)andRecife

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Fig.4.Totalwaterconsumptionandconsumptionperpassengerinthe10Brazilianairportswithgreatestpassengertrafﬁc.

(REC),present indices of 23,23, 29 and24L/passenger, respec-tively.However,ManausAirport(MAO)transportedtwomillion passengersin2010andhadanindexof82L/passenger.

Fig.5presentspassengertrafﬁcandtheL/passengerindexfor themaininternationalairportsandforBrazilianairportswithlarge passengermovement.

RomeAirportpossessesanaverageconsumptionindexandis notableforthelargeamountofwateritrecycles(approximately 1700,000m3_in_2010,_according_to_ADR,₂₀₀₉_),_as_shown_in_Fig.₂_.

InBrazil,GaleãoAirportpresentsa highconsumptionindexbut istheonlyoneinthecountrywhichimplementssewageefﬂuent reuseandrainwateruse.

Thus,wehighlightthenecessityofstudyingwaterconsumption inairportenvironments,takingintoaccountthesepeculiaritiesin ordertoobtaininformationthatisrelatedtosuchconsumption,so astoguideactionsrelatingtowaterresourceaswellaspoliciesthat promoteitspreservation,rationaluseandthesearchfor alterna-tivesources.InBrazil,suchstudieshaveanevengreaterurgency, becausemostairportsareundergoingrenovationsandare expand-ingtoaccommodatetwoimportantinternationalsportingevents, theFIFAWorldCupin2014andtheOlympicGamesin2016.

4. Mainattitudesrelatedtotheefﬁcientuseofwater: experienceofmajorairports

Asmentioned inSections3 and 4,airports withalarge cir-culationofpeoplehaveimplementedactionsaimedatachieving

theefﬁcientuseofwaterresources.Inthefollowingsectionswe presentthemostrelevantactionstheseairportshavecarriedout.

4.1. Waterconsumptionmetering

Aprogramfortherationaluseofwaterbeginswithasystematic evaluationoftheactivitiesandsectorsinwhichwaterisused.Any suchevaluationmustbecontinuousifthecontrolofwater con-sumptionthatisnecessaryfortheidentiﬁcationofleaksandlosses istobeachieved.Watermeteringacrosstheentiredistributionnet isessentialandanimportantstageofthisanalysis.

Concerns regarding control of water useare experienced in manyairports.AtTorontoPearsonInternationalAirport,baseline datahasbeencollectedandindividualmetersinstalledforallfood andbeveragefranchisesinordertoreducetheamountofpotable waterusedattheairport(GTAA,2006).

Initiatives such as leak control and monitoring of demand are also widelyemployed. Actions toreduce water use and to requirebestpracticesregardingwater efﬁciencymeasureshave beenadoptedatSydneyAirport.Amongtheseinitiatives,a com-pleteleakdetectionprogramandasophisticatedreal-timewater demandmonitoringsystemhavebeendeveloped(SYD,2009a).A monitoringprogramforwateruseandforregularlycheckingfor leakshasbeeninstigatedatLondonHeathrowInternational Air-port(LHR,2010).Thereisalsoanongoingleakdetectionprogram atManchesterAirporttoensureanyleaksarequicklydetectedand repaired(MAG,2007).

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AtParis Airports, meshed distribution networks of drinking wateraremonitoredconstantly,andoperatingdataaredelivered toaninformationtechnologycenterusingﬁber-opticcables.Alerts areroutedautomaticallytoanemergencyphonethatenablesa rapidreactionintheeventofaleak,andwaterqualityisconstantly controlled(ADP,2010).

ConfinsAirport,theseventhlargestairportinBrazilwith pas-senger traffic of 7.1 million in 2010, is implementing a model consumptionmanagementsystemthathasbeenoperationalsince theendof2012.Theconsumptionof48meteringpointswillbe monitoredcontinuously and a software using data from these pointswillmakeitpossibletoassessifconsumptionisasexpected andtoidentifyabnormalpatternsandleaks.Areportisgenerated withaconsumptiondiagnosis,makingiteasiertoadoptspecific policiesandmeasurestoreduceconsumption.

4.2. Watersavingsanitaryﬁxtures

Majorairports have adoptedprograms toreplacetheir con-ventionalsanitaryfixturesbywatersavingequipmentandhave achievedsignificantreductionsinwaterconsumption.Atlanta Air-portreplaced,in 2007,630toiletsthatused 6.05Lper flushby newonesthatused4.84L.Additionally,around1200urinalsthat used3.8Lperflushwerereplacedbyonesusing1.9L(DOAAtlanta, 2009).

FortLauderdaleHollywoodInternationalAirport(Florida,EUA) had21,876,444passengersin2010(BCAD,2010).Accordingtothe CDA(2010),thisairportconsumedapproximately246,000m3 _of

waterfromOctober2005toSeptember2006.Theinstallationof watersavingsanitaryﬁxturesinthebathroomscost$234,000,00 andsaved163,000m3_of_potable_water_after_one_year,_representing

savingsof$281,000.00andareturnontheinvestmentwithin10 months.

InFrankfurtAirport,theuseofﬂowlimitationequipmenton faucetshashelpedtosavethousandsofcubicmetersofwaterevery year,andtheinstallationofwaterlessurinalshassaved approx-imately 4.2million litersof drinkingwater each year.The cost savingsamounttoapproximatelyD33,000eachyear(FraportAG, 2011).

DubaiInternationalAirporthasinstalledsensor-operatedwash basinfaucetsinalltoiletsand,althoughnogreywatersystemsare used,theyhavebeeninstalledand somearehalf-flushsystems. Inaddition,astandardautomatic1.6IGflushhasbeeninstalledin thebathrooms,ashasadualflushingmechanism3.0/6.0Ltoreduce waterwastagethroughmanualflushingfromtoilets(DCADubai, 2004).

Otherimportant airports,suchasAmsterdam,SãoFrancisco, Fiumicino, Sydney, Toronto, Narita, Manchester and London-Heathrow,havehadequipmentinstalledinordertosave water andencouragewaterconservation.Tapswithwatersavingnozzles (aerators)thatareabletooptimizetheflushingprocess,low-flow restroomfixtures,automatic-shutoffvalves,automaticballcocks andurinalsareverycommonintoiletareasandarearequirement inthedesignofanynewbuildingsattheseairports(ADR,2009; LHR,2010;MAG,2007;NIAC,2011;SchipholGroup,2011;SFIA, 2011;SYD,2009a;GTAA,2006).

Theairports of Recifeand Galeãostand outin the Brazilian context.InRecife,toiletshavebeeninstalledusingatechnology similartothatemployedinaircraftinwhichﬂushingisoperated undervacuum,signiﬁcantlyreducingwaterconsumption.The vac-uumsystemreducestotalconsumptionattheairportby30%.The estimatedmonthlyconsumptionis21,400m3_,_much_less_than_the

30,600m3_that_would_be_used_by_a_conventional_system._The_latter

consumesanaverageof10Lperﬂushwhereastheconsumption ofthevacuumsystemcorrespondsto1.2Lperﬂush(Infraero, per-sonalcommunication).Manyactionshavebeenimplementedat

Galeãotoimprove itswater managementsystem,includingthe replacementofthewatermains,networksanddistributionlines thatcreatedahighriskofleaks,aswellasthesubstitutionofﬂow controlvalvesandtheinstallationofﬂoatswitches inthe stor-agecenters.Storageunitsand pumpingstations withstructural problemswererenovated(PizzatoandAlves,2010).However,even thoughgreateffortshavebeenmade,thereisstillmuchto accom-plishinthisairportbecauseitpresentshighconsumptionindicesin comparisontointernationalairportsofthesamesize,asdiscussed inSection3.

4.3. Waterreuse

Waterreusemeasuresareusuallymotivatedbyscarcity,and alsobyincreasinglystringentenvironmentalrestrictions.Thenew technologiesdevelopedforwastewater treatmentenablereuse; however,itseffectiveusedependslargelyontheeconomic advan-tagesthatwillberealizedaswaterpricesincrease(Casanietal., 2005).

Itisdifficulttomeasuretherealeconomicvalueofwaterreuse becausethebenefitsareembeddedinprotectionofsurfacewater resources,localeconomicdevelopment,publichealthprotection andmaintainingcurrent watersources forlonger,amongother aspects (Anderson, 2003). Economic costs cannot be evaluated withoutalsoconsideringsocialandenvironmentalcostsand bene-fits.Waterreuseisnotonlyanenvironmentallycorrectalternative butalsoarationalandsmartwayofusingrawmaterial.

Theachievementofgoodresultsdependsonthecommitment of professionals who have been trained to develop and adopt adequateconceptsand technologiesfor efﬁcienttreatmentand environmentalsustainability.AccordingtoUrkiagaetal.(2008), howeverreuseisemployeditiscriticaltoobservethebasic prin-ciplesthatshouldguidesuchpractice:thepreservationofusers’ heath,consistentcompliancewithqualityrequirementsrelatedto theintendeduseand protectionofthematerialandequipment incorporatedintoreusesystems,aswellastheiroperationalcosts. Airportspresentlimitationsandpotentialities,aswellasother industrialtypologies.Theairlinesof190MemberStatesofthe Inter-nationalCivilAviationOrganization(ICAO)carriedapproximately 2.5billionpassengersin2010,showinganincreaseofabout8.7% over2009(ICAO,2010).AccordingtotheWorldHealth Organiza-tion(WHO,2009),thisindicatesthereisapotentialforcommercial airtransporttospreadcommunicablediseases.Thus,the imple-mentationofwaterreuseinairportsshouldbestrictlymonitored inordertominimizetheassociatedrisks.

FrankfurtAirporthassince2001maintaineditspotablewater volumeatthesamelevel,despiteincreasingpassengernumbers. Theconceptbehindthepotablewatersupplyintheairportarea is thatpotable water consumption shouldbereduced byusing servicewaterinstead.Theservicewatershareinthetotalwater consumptionhasrisento18%overthepasttenyears.Inthesame period,potablewaterconsumptionpertrafﬁcunithasdeclinedby over20%.In2010,potablewaterconsumptionwas1.46millionm3_,

whichequatesto19litersperpassenger;theservicewatervolume amountedto319,000m3₍_Fraport_AG,₂₀₁₀_)._Fiumicino_Airport_also

reuseswaterandconsumesmorereusewaterthanpotablewater. Fig.6showsthehistoryofpotableandreusewaterconsumptionin ordertocompareFiumicinoandFrankfurtairports.

Experienceswithrationaluseofwaterinairports,suchasusing rainwater,greywater,seawaterandreusingwastewaterare pre-sentedinSections4.3.1–4.3.4.

4.3.1. Rainwateruse

Rainwaterharvestingisatechniqueadoptedgloballyandwhich isbecomingincreasinglyusefulinthecurrentcontextofthe qual-itativeandquantitativescarcityofwaterresources.Rainwatercan

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Fig.6.AnnualpotablewaterconsumptionandreusewaterintheairportsofFiumicinoandFrankfurt(ADR,2009andFraportAG,2010).

beusedindomestic,industrialandagriculturalactivities,among others,providingasigniﬁcantreductionincostsbyusinga non-traditionalwatersource(AladenolaandAdeboye,2010).

Airportenvironments,becauseofimpermeabilizationofthesoil, containalargeamountofsuperﬁciallydrainedwater,which rep-resents great potential for storageduring therainy period and usefornon-potable activities.Thispotential,however, depends ontheregionwheretheairportislocatedandonthe technolo-gies available for treating this water. Deicing salt applications arecommonincoldclimateregionsand,accordingtoDaietal. (2012),thesechemicalshavenegativeeffectsontheenvironment (surfacewater,groundwater,plantsandanimals)thatshouldbe takenintoaccountwhenselectingarainwatertreatment technol-ogy.Additionally,eliminatingpollutantsfromroadsandrunways canbe veryexpensive; a comprehensivestudyof theavailable technologies and their economic feasibility must therefore be undertaken.

FraportAGoperatestworainwatertreatmentfacilities,located inCargoCitySouthandatTerminal2atFrankfurtInternational Airport.Attimesoflowrainfall,treatedwaterfromtheRiverMain isfedintothesystem.Thisservicewaterisfedviaseparate sup-plynetworkstosprinklersystems,toiletcisternsandsystemsfor wateringlandscapedareas.InCargoCitySouth,theservicewater issuppliedthroughout,andtheterminalsarealsosuppliedwith servicewater.Thesamesystemisstillundergoingfurther expan-sioninTerminal1and neighboringofﬁce buildings.FraportAG operatesastormwaternetworkwithalengthofapproximately 200km,23rainwatercontainmentbasinswithastoragevolumeof 100,000m3_and₄₇_light_liquid_separators₍_Fraport_AG,₂₀₁₀_).

OrlyandCharlesdeGaulleAirportsinParishave,since1996 and1999,respectively,beenequippedwitharainwatertreatment plant.In2005,theconstructioncostOrlyD740,000andCharles deGaulleD900,000.AtOrly,rainwaterisusedtosupplytheair conditioningsystemandheatingnetwork,andasmallpartisused forﬁrecontrol,saving70,000m3_/year_of_potable_water₍_ADP,₂₀₁₀_).

The Maintenance Division of the Department of Aviation in AtlantaAirporthasinstalledthree11.37m3_water_cisterns,_which

capturewaterrunofffromtheroof.Thewatercollectedfromthe cisternsisusedtoirrigatethexeriscapedaswellasotherareas. During thehottermonths (Mayuntil August),theMaintenance Divisionusesapproximately36.37m3_of_harvested_rainwater_per

month(DOAAtlanta,2009).

InNarita,rainwatertreatmentfacilitiesproducegreywaterfrom rainwaterthatispumpedupfromtheholdingpondsforuseas chil-lingwaterandauxiliarysuppliestothecentralheatingandcooling plants.Theairportalsobegantouserecycledwaterforﬂushingin thepassengerterminaltoiletsinApril2010(NIAC,2011).

SomebuildingsatBrusselsInternationalAirportareﬁttedwith sixrainwatercollectors,eachof10m3_._The_rainwater_is_used_for

ﬂushingtoiletsandcleaningpurposes(BAC,2010).

AccordingtotheSchipholGroup,theAmsterdamAirport col-lectsrainanddrainwaterforreuseasrinsewater(SchipholGroup, 2011).

HeathrowandZurichAirportscollect59and10thousandm3_,

respectively,ofrainwatereachyear.Arainwaterharvestingscheme atLondon-HeathrowAirporthasthepotentialtoreusearound85% oftherainfallwhich,togetherwiththeuseofboreholewater, pro-videsTerminal5with70%ofitsnon-potable waterneeds. This rainwaterharvestingschemeisthebiggestofitskindinEurope (LHR, 2010).Zurich Airport uses rainwater to supply technical installationsandalsofortoiletﬂushing(ZIA,2010).AtManchester Airport, there is a current review of opportunities for harvest-ingrainwaterfromroofsandhardsurfacesfornon-potableuses, includinguseinroadsweepersandforﬁretraining(MAG,2007).

Rainwaterisoneof thealternativewater suppliesemployed at Galeão Airport. In 2009, thecompany responsible for water resourcesmanagementintheairportimplementedrainwater har-vestingfromtherooftops.The1500m3 _collected_every_month_is

treatedand combinedwithtreatedsewageefﬂuentforreusein coolingsystems(PizzatoandAlves,2010).

4.3.2. Greywaterreuse

Greywaterconsists of the effluentfrom lavatories, showers, kitchensinksandwashingmachines(HernándezLealetal.,2011; Liuetal.,2010;OttosonandStenstrom,2003)anddoesnotreceive anycontributionfromsewage.Thisis relatedtotheconceptof effluentsegregationatsource,whichmakestreatmentandreuse easier.Effluent suchasthis presentsa lower pollutant concen-trationincomparisonwithdomesticsewageandonlyrepresents asmallfractionoftheeffluentgeneratedinabuilding;itisone ofthemainalternativesforreducingpotablewaterconsumption (GilboaandFriedler,2008).Lietal.(2009)reviewsomegreywater treatmenttechnologies,includingphysical,chemicalandbiological processes,whichareusuallyprecededbyasolid–liquidseparation step(septictank,filterbags,screenandfilters)asapre-treatment, followedbyadisinfectionstepaspost-treatment.Accordingtothe authors,thephysicalprocessesalonearenotsufficienttoguarantee anadequatereductionintheorganics,nutrientsandsurfactants. Chemicalprocessescanhoweverefficientlyremovethesuspended solids,organicmaterialsandsurfactantsinlowstrength greywa-ter.Thecombinationofaerobicbiologicalprocesseswithphysical filtrationanddisinfectionisconsideredtobethemosteconomical andfeasiblesolutionforgreywaterrecycling.HernándezLealetal. (2011)statethatanaerobicmethodsareaninterestingalternative,

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giventhelowcostandpotentialforenergyproduction.Theauthors highlighttheapplicabilityofsuchsystemstogreywatertreatment, sincethelownutrientlevelscanlimittheefﬁciencyofsomeaerobic systems.

Oftheairportswhichusegreywaterasanalternativesourceof water,wecanhighlighttheairportsofHongKonginChina,Narita inJapanandFiumicinoinItaly.HongKongAirporthasatreatment systemthattreatsgreywatercollectedfromaircraftcatering facili-tiesandterminalbuildingkitchenstogetherwithwaterrunofffrom aircraftwashingactivities.Treatedwaterisre-usedforirrigation. In2010thetreatmentplantprocessed1.4millionm3_of_greywater,

meetingalloftheairport’slandscapeirrigationneeds.Inthenear future,theairportplanstoinstallanewmembranebiological reac-torintheplanttoenhancethequalityofthetreatedwater(HKIA, 2011).

Greywaterfromthepassengerterminal restaurantsofNarita Airportistreatedatthekitchenwastewatertreatmentfacilityand isusedasﬂushingwaterinthepassengerterminaltoilets(NIAC, 2011).

AtFiumicinoAirportinRome,greywaterderivedfromTerminal restaurantsandfromthecompanyresponsibleforpreparingthe foodservedintheaircraftiscollectedand,afterphysicalprocesses toseparateoutthegrease,istreatedtogetherwithdomesticsewage usinganactivatedsludgebiologicalsystemforreuseinnon-potable activities(ADR,2009).

4.3.3. Seawaterreuse

Afurtheralternativesourceissalinewater.Althoughitisrichin substancesthatarenotdesirableforreusepurposes,suchassodium chloride,thiswaterhasbecomeattractivetoairportssituatednear thecoast,afterpropertreatment.

Seawater supplies 41% of the water demand of Hong Kong Airport,representing approximately380,000m3_/d._A _small_part

(300m3_/d)_is_used_for_aircraft_lavatory_waste,_about₇₃₀₀_m3_/d_is

usedfortoiletﬂushingandtherestisusedinthecoolingsystem. Thesavingsgeneratedbytheintroductionoftheseawatersupply is$500,000/year(HKIA,2011).

4.3.4. Sewageefﬂuentreuse

Wastewaterandsewageeffluentreusehaverecentlybeen con-sideredas potentialoptionstomanage increasingwater stress. Optionsforreusedependonthequalityoftheeffluentproduced after sewage treatment (Megdal, 2006). Reclaimed water from domesticsewageisusedfrequentlyinmanyapplicationssuchas irrigation,toiletflushing,cleaning,industrialreuseand environ-mentalenhancement(Changetal.,2007;Chiouetal.,2007;Jimenez andChavez,2003;Jimenezetal.,2001).Becauseofthepotentialrisk tohealthduetothepresenceofpathogenicmicroorganisms,reuse oftreated sewage needscarefulevaluation (JamwalandMittal, 2010)andishighlydependentonthetreatmenttechnologyused.

Currently, there is a global increase in thereuse of treated domesticsewage,mostlyincountriesfacingwatershortagesand thathaveimplementedanexpensivepotablewaterusefee. Fol-lowingthisglobaltrend,airportsareincreasinglyadoptingsimilar practices.AtFiumicino,sanitary,kitchenandrestaurantefﬂuent aretreatedbyactivatedsludgeandultravioletdisinfectionbefore beingreusedinlandscapeirrigation,airconditioningsystemsand ﬁrecontrol(ADR,2009).

QingdaoAirportinChina,which transported8.2million pas-sengersin2008,usesmembranebioreactorstotreatitsefﬂuent. AccordingtoLiuetal.(2007),thesystemcost$800,000,hasthe capacitytotreat1000m3_/d_and_occupies_an_area_of_10,000_m2_._The

treatedefﬂuentisreusedinthemaintenanceoftheairport com-plex:30%forafforestation,40%forirrigationofgreenareas,20%for theﬁrecontrolsystemand10%isdischarged.

DubaiAirport hasan online oil-water separator systemand awastewatertreatmentplant,operated bya technicianonsite. Therecycledwateris usedfor washingvehiclesand withinthe engineering works. All the vehicles operated by the Engineer-ing Services Division are cleaned using recycled water and all drainagere-entersthewastewatertreatmentplant.Thisplant cur-rentlytreats80m3_of_sewage_on_a_daily_basis._The_Department_of

CivilAviationofDubai,which islocatedintheairportcomplex, hasinvestigatedtheconsumptionratesforirrigation,ﬁndingthat 960,000m3_/month_of_water_is_used_for_irrigation_in_85,000_m2

land-scapingprojects.Inordertominimizetheseconsumptionrates,the airportimplementedsewageefﬂuentuseforirrigation(DCADubai, 2004).

TheactualwatersavingsmadebyKingsfordSmithAirport,in Sydney,Australia,ﬂuctuateaccordingtodemandand,in2009,the watertreatmentplantsavedanaverageof350m3_of_fresh_potable

watereach day.In2010and2011,thisincreasedtoanaverage of580m3 _per_day_and_is_expected_to_increase_up_to_a_maximum

of1000m3_per_day_over_the_next₂₀_years._The_water_treatment

plantprocessesrawsewagefromtheInternationalTerminaland itssurroundings,includingthemulti-storycarpark,UlmBuilding (SydneyAirport’sCorporateOffice)andtheCustomsHouse.The treatmentplantproducestwostreamsofrecycledwater.One com-prisesrecycledwaterthatispipedtotheInternationalTerminalto beusedfortoiletflushing.Thereare526toiletsand212urinals con-nectedtothissystem,thatwillallbeflushedusingrecycledwater. Theotherstreamcomprisesreverseosmosiswaterthatispipedto theCentralServicesBuildingandusedinair-conditioningcooling towers(SYD,2009b).

InBrazil,Galeãohasasewageefﬂuentreusesystem.Theefﬂuent ismixedwith8m3_h−1_of_rainwater_or_with_well_water_in_order

toachievethemaximumproductionefﬁciencyforreuse,whichis 20m3_h−1_._The_mixture_is_pre-treated_by_coagulation,_ﬁltration_in

sandﬁlters,ﬁltrationwithactivatedcarbonandthenseparatedby membranes(reverseosmosis),whichresultsinanexcellentwater qualitysuitableforsupplyingthecoolingtowerswithallnecessary securityrequirements(PizzatoandAlves,2010).

4.4. Othermeasures

4.4.1. Landscapemanagement

Airportcomplexesusuallyhavelargelandscapedareasthatplay anestheticroleaswellasprotectsoilandminimizethecarriageof sedimentsintodrainagechannels.Maintainingareassuchasthese usewater,sotheirmanagementmustbebasedonthepremiseof theefﬁcientuseofthisresource.

AtlantaAirporthasarigorousplanningprogramfortheir land-scapedareas,named“XeriscapeLandscaping”.Theplantsmeetthe requirementsforlowwaterdemand(xerophilousplantsareusually selected).Areaswherelandscapeisparticularlyimportant esthet-icallyareprioritized(DOAAtlanta,2009).AccordingtotheCDA (2010),thechoiceofspeciesshouldbeofthosewiththelowest growthrate,whichtoleratedroughtsandwhichdonotattractbirds orotheranimals.

4.4.2. Airconditioningsystems

Air cooling systems ensure the comfort of passengers and employeesbutconsumelargeamountsofwater.Theuseofrecycled waterinsuchsystems,ormoreefﬁcientheatexchangers,is essen-tialifwaterconsumptioninairportsistobereduced.

At Atlanta Airport, after steam-powered refrigerators were replacedbyelectricchillers,theneedforwatertogeneratesteam waseliminated,andwaterconsumptionintheboilerswas there-forereduced(DOAAtlanta,2009).

AwatertreatmentsystemwasinstalledinAmsterdam Inter-nationalAirportforsupplyingwatertothecoolingtowersonthe

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roofsofTerminals2and3in2010.Thepurposewastoreducethe mineralcontentofthecoolingwaterandachieveasavingofupto 20%ofthewatersupply(SchipholGroup,2011.

5. Finalconsiderations

Themostrelevantinformationpresentedinthispaperis: -Waterconsumptioninairportshasbeenassessedandcompared

intermsofpassengertrafﬁcandtheindexofL/passenger,whichis widelyusedinairportannualreports.Thisstudyemphasizesthat inmanysituationssuchanindexdoesnothaveadirectinﬂuence onconsumption.Othervariablespertainingtoairportactivities shouldbestudiedinordertodetermineamoreaccurateindex toassess,compareandevenpredictwaterconsumptioninsuch environments.

-Airportenvironmentsconsumelargeamountsofwaterto main-taininfrastructureandoperationsand,inmostcases,thisvolume isusedtomeetnon-potabledemands,suchasfirecontrol, wash-ingoffloorsandaircraft,landscapeirrigationandairconditioning systems,whichcanbemettoalargeextentbyalternativewater sources(rainwaterandtreatedeffluent,forinstance).

-These environments have extensive impermeable areas (run-waysandrooftops)thatcanbeusedtoharvestlargevolumes ofrainwater.Manyairportsoperationsdonottakeadvantageof therainwateravailablefromrunwaysandpavedareas,which isalreadycollectedandtreatedtoavoidcontaminationofwater bodiesbyoilandgrease.Itisimportanttohighlight,however,that thispotentialshouldbeassessedinthecontextoftheeconomic feasibilityofthecurrenttechnologiesavailableforremoving pol-lutantsfromsuchareas.

-Someairportshaveahighproductionofwastewater,whichcould makefeasibletheimplementationofreusingsewageefﬂuentas wellasgreywater,aftertreatment.Examplesofairportsthatare alreadyimplementingreuseprovethatthispracticeistechnically andeconomicallyfeasible,aswellasproviding environmental gainsassociatedwithsavingpotablewater.

-Increasesinairportcapacityandchangesininfrastructureshould befollowedbytheinstallationofwatersavingsanitaryﬁxtures andamodernandefﬁcientsystemforwatermetering,aimedat monitoringconsumptionanddevelopingpoliciesforits reduc-tion.

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