GRADE 1 WATER DISTRIBUTION STUDY QUESTIONS WITH COMPLETE SOLUTIONS

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