WATER DISTRIBUTION EXAM 1 WITH
COMPLETE SOLUTIONS
Backasiphonagea-aans--
backflowadueatoanegativeaorareducedapressureainawaterasystem.aoccursaduringalowapressur
eaeventsasuchaasaaalinealeak
Reverseaflowacausedabyaaalossaofasupplyapressure
BackaPressurea-aans--
Isacausedawhenaaapotableawaterasystemaisaconnectedatoaaanonapotableasupplyaoperatingau
nderaaahigherapressureathatapushesacontaminatedaliquidabackaintoatheapublicawaterasystem
BackaPressurea-aans--
Occursawhenatheapressureaofatheaconnectedasystemaexceedsatheapressureaofatheadrinkinga
waterasystem
Backflowa-aans--Occursawhenatheapressureaofatheanon-
potableasystem.aExceedsatheapositiveapressureainatheawateradistributionalines.
Diseasesaattributedatoacross-connections:a-aans--
Dysentery•aGastroenteritis•aHepatitis•aSalmonellas
DirectaCross-Connectiona-aans--Aadirectacross-
connectionaisasubjectatoabackpressureaorabacksiphonage.
Undesirableamaterialabeingapushedaintoatheasystem.
a
IndirectaCross-Connectiona-aans--Undesirableamaterialabeingapulledaintoatheasystem.
Anaindirectacross-connectionaisasubjectatoaback-siphonageaonly.
a
AiraGapa-aans--AiraGap:aphysicalaseparationaofatheapotableaandanon-
potableasystemabyaanaairaspace.a
Theasimplest,amostareliableawayatoaprovideabackflowaprevention
a
ReducedaPressurea(RP)aZoneaBackflowaPreventera-aans--
Providesatheagreatestaprotectionaagainstabackflowacausedabyaback-pressureaandaback-
siphonage.
TheaRPZashouldabeausedawhereacontinuousapressureaorahighahazardaconditionsaexist,
, ReducedaPressurea(RP)aZoneaBackflowaPreventera-aans--
Mustabeatestedaannuallyaandainternalapartsareplacedaeveryafiveayears.
PressureaVacuumaBreakersa(PVB)a-aans--Mustabeausedaunderacontinuousapressure.
Theyamustabeainstalledaataleasta12ainchesaaboveatheausageapointatoapreventaback-
a
siphonage.
AtmosphericaVacuumaBreakersa(AVB)a-aans--Intendedatoaprotectaagainstaback-
siphonageabutanotabackapressure.aCheckavalveaandaventaopenatoaatmosphere.
Corrosionaisathearesult?a-aans--Corrosionaisathearesultaofaanaelectrochemicalareaction
LeadaandaCopperaRulea-aans--
Protectapublicahealthabyaminimizingatheaamountaofaleadaand/oracopperadissolvingaintoatapaw
ater.
Anodea(GalvanicaCorrosion)a-aans--whereaelectronsaarealostathroughatheametal.
Cathode.(GalvanicaCorrosion)a-aans--
:awhereaelectronsaareagainedaandathenaleaveatheametal
CalciumaCarbonatea-aans--
Wateraisaconsideredastableawhenaitaisajustasaturatedawithacalciumacarbonate.
UsedaforacorrosionaprotectionaofapipeabyaaathinafilmaofaCaCo3aonatheainterioraofapipes.
LangelieraSaturationaIndexa(LSI)a-aans--
LSIavaluesa>zeroaindicateascalingapotentiala(i.e.,aprecipitating).
Theaidealarangeaforabalancedawateraisa-0.3atoa+0.3
LSIaisaaameasureaofaaasolution'saabilityatoadissolveaoradepositacalciumacarbonate,aisaoftenau
sedaasaanaindicatoraofatheacorrosivityaofawater.
pH:aAsapHadecreases?a-aans--corrosionaincreases.
Inamostacases,aasaalkalinityaincreases,a-aans--corrosionadecreases.
AsaTDSaincreasesa(Totaladissolvedasolidsa(TDS)a-aans--corrosionaincreases
Temperature:aAsatemperatureaincreasesa-aans--corrosionaincreases.
Dissolvedaoxygena(DO):aAsaDOaincreasesa-aans--corrosionaincreases.
Chlorides,aSulfates,aNitrates:aAsatheseaincreasea-aans--corrosionaincreases
COMPLETE SOLUTIONS
Backasiphonagea-aans--
backflowadueatoanegativeaorareducedapressureainawaterasystem.aoccursaduringalowapressur
eaeventsasuchaasaaalinealeak
Reverseaflowacausedabyaaalossaofasupplyapressure
BackaPressurea-aans--
Isacausedawhenaaapotableawaterasystemaisaconnectedatoaaanonapotableasupplyaoperatingau
nderaaahigherapressureathatapushesacontaminatedaliquidabackaintoatheapublicawaterasystem
BackaPressurea-aans--
Occursawhenatheapressureaofatheaconnectedasystemaexceedsatheapressureaofatheadrinkinga
waterasystem
Backflowa-aans--Occursawhenatheapressureaofatheanon-
potableasystem.aExceedsatheapositiveapressureainatheawateradistributionalines.
Diseasesaattributedatoacross-connections:a-aans--
Dysentery•aGastroenteritis•aHepatitis•aSalmonellas
DirectaCross-Connectiona-aans--Aadirectacross-
connectionaisasubjectatoabackpressureaorabacksiphonage.
Undesirableamaterialabeingapushedaintoatheasystem.
a
IndirectaCross-Connectiona-aans--Undesirableamaterialabeingapulledaintoatheasystem.
Anaindirectacross-connectionaisasubjectatoaback-siphonageaonly.
a
AiraGapa-aans--AiraGap:aphysicalaseparationaofatheapotableaandanon-
potableasystemabyaanaairaspace.a
Theasimplest,amostareliableawayatoaprovideabackflowaprevention
a
ReducedaPressurea(RP)aZoneaBackflowaPreventera-aans--
Providesatheagreatestaprotectionaagainstabackflowacausedabyaback-pressureaandaback-
siphonage.
TheaRPZashouldabeausedawhereacontinuousapressureaorahighahazardaconditionsaexist,
, ReducedaPressurea(RP)aZoneaBackflowaPreventera-aans--
Mustabeatestedaannuallyaandainternalapartsareplacedaeveryafiveayears.
PressureaVacuumaBreakersa(PVB)a-aans--Mustabeausedaunderacontinuousapressure.
Theyamustabeainstalledaataleasta12ainchesaaboveatheausageapointatoapreventaback-
a
siphonage.
AtmosphericaVacuumaBreakersa(AVB)a-aans--Intendedatoaprotectaagainstaback-
siphonageabutanotabackapressure.aCheckavalveaandaventaopenatoaatmosphere.
Corrosionaisathearesult?a-aans--Corrosionaisathearesultaofaanaelectrochemicalareaction
LeadaandaCopperaRulea-aans--
Protectapublicahealthabyaminimizingatheaamountaofaleadaand/oracopperadissolvingaintoatapaw
ater.
Anodea(GalvanicaCorrosion)a-aans--whereaelectronsaarealostathroughatheametal.
Cathode.(GalvanicaCorrosion)a-aans--
:awhereaelectronsaareagainedaandathenaleaveatheametal
CalciumaCarbonatea-aans--
Wateraisaconsideredastableawhenaitaisajustasaturatedawithacalciumacarbonate.
UsedaforacorrosionaprotectionaofapipeabyaaathinafilmaofaCaCo3aonatheainterioraofapipes.
LangelieraSaturationaIndexa(LSI)a-aans--
LSIavaluesa>zeroaindicateascalingapotentiala(i.e.,aprecipitating).
Theaidealarangeaforabalancedawateraisa-0.3atoa+0.3
LSIaisaaameasureaofaaasolution'saabilityatoadissolveaoradepositacalciumacarbonate,aisaoftenau
sedaasaanaindicatoraofatheacorrosivityaofawater.
pH:aAsapHadecreases?a-aans--corrosionaincreases.
Inamostacases,aasaalkalinityaincreases,a-aans--corrosionadecreases.
AsaTDSaincreasesa(Totaladissolvedasolidsa(TDS)a-aans--corrosionaincreases
Temperature:aAsatemperatureaincreasesa-aans--corrosionaincreases.
Dissolvedaoxygena(DO):aAsaDOaincreasesa-aans--corrosionaincreases.
Chlorides,aSulfates,aNitrates:aAsatheseaincreasea-aans--corrosionaincreases
