Mg equivalent CaCO 3 /Là2.4797[Ca,mg/L]á4.118[Mg,mg/L]
The US Geological Survey'sWaterSupplyPaperNumber658,a frequently
citedstandard in the US (AmericanPublicHealthAssociation,1985),classifies
waterhardnessaccording to parameters presentedin Table28.2.The relative
effectivenessof the variousclassesof cleaningcompoundsin achieving the
various functions of cleaningis summarizedin Table28.3.
As notedpreviously,waterprimarilyservesas the carrierof the cleaning
compound.Waterhardnessmayimpactits abilityto retainthe cleaningagent
in solutionwhile simultaneously maintaining its optimalstate of activity.
Moreover, the minerals in hard water will react with certainsoaps and
detergentsto formsticky,insolublefilms. Thisfilmwilldepositontothe
cleaning tank'swalls andalso on the surface of the cleaned equipment.
Additionally,hardwatercan promote calciumdepositsand the formationof
rust.An effectiveCOPcleaningprocessmusthavean adequatesupplyof soft,
hot water.In thoseinstanceswheresoft wateris not readilyavailable,it is
recommendedthat the supplybe conditioned.Waterconditioning,rendering
hardwatersoft,is simplythe removalof the calciumand magnesiumions from
the watersource.Characterizingthe qualityand chemistryof the watersource
Table28.2 US GeologicalSurveywaterhardnessdata
Hardness Concentration
Softwater 0±51.3mg/L(1.0±3.5grains/gallon)
Moderatehardwater 51.3±119.7mg/L(3.5±7.0grains/gallon)
Hardwater 119.7±179.5mg/L(7.0±10.5grains/gallon)
Veryhardwater Greaterthan179.5mg/L(> 10.5grains/gallon)
Table28.3 Activityand functionof cleaningcompounds
Functionin cleaning Activity
Corrosion Rustprevention
Rinsing Reductionof the surfacetensionof watertherebypermitting
cleanequipmentto draindry
Dispersion Reductionof clumpsof suspendedmatterinto smallparticles
Emulsification Reductionin fat globulesize and theirdispersionin the
cleaningsolution
Peptizing Formationof colloidalsolutionsfrompartiallysoluble
materials
Wetting Actionof reducingthe surfacetensionof water
Saponification Actionof alkalion fats to formsoap
Chelating Reactionof organiccompoundswithmetalions dissolvedin
water(i.e. calcium,magnesium,manganese,and iron)to
preventfilmformation
452 Handbookof hygiene controlin the foodindustry