Basic Chemistry for Water Basic Chemistry for Water Plant OperatorsPlant Operators

MatterMatterSolidsSolidsLiquidsLiquidsGassesGasses

Pure ElementsPure Elements

Elements are matter built up from subatomic particlesElements are matter built up from subatomic particlesProperties are determined by their nucleus ( protons Properties are determined by their nucleus ( protons and neutrons) and by their electron shells. and neutrons) and by their electron shells. All of the atoms of an element have the same All of the atoms of an element have the same number of protons in their nuclei. number of protons in their nuclei. Elements do not break down into simpler elements. Elements do not break down into simpler elements. There are over 118 known elements.There are over 118 known elements.92 occur naturally, and others have been produced in 92 occur naturally, and others have been produced in the laboratorythe laboratory

Periodic Table of the ElementsPeriodic Table of the Elements

Electrons in Outer ShellElectrons in Outer Shell

The Periodic ChartThe Periodic ChartUse of Atomic WeightUse of Atomic Weight

3

OOxygen

15.99

Atomic Number

Symbol

Name

Atomic Weight

Calculating Molecular Weight Calculating Molecular Weight of a Compoundof a Compound

The Molecular Weight of a Compound is the The Molecular Weight of a Compound is the sum of the Atomic Weights in the Chemical sum of the Atomic Weights in the Chemical Formula. For example for HFormula. For example for H22OO

Hydrogen Atomic Weight = 1Hydrogen Atomic Weight = 1Oxygen Atomic Weight = 16Oxygen Atomic Weight = 16

There are 2 Hydrogen Atoms so the There are 2 Hydrogen Atoms so the molecular weight of Hmolecular weight of H22O is 2 + 16 = 18O is 2 + 16 = 18

Element Symbol Element Symbol Element Symbol

Aluminum Al Chromium Cr Oxygen O

Arsenic* As Fluorine† F Phosphorus P

Barium* Ba Hydrogen H Potassium K

Boron B Iodine I Radium* Ra

Bromine Br Iron Fe Selenium* Se

Cadmium* Cd Lead* Pb Silicon Si

Calcium Ca Magnesium Mg Silver* Ag

Carbon C Manganese Mn Sodium Na

Chlorine Cl Mercury* Hg Strontium* Sr

Copper Cu Nitrogen N Sulfur S

Common Elements of Water Treatment

Equivalent WeightEquivalent Weight

The equivalent weight of an element is The equivalent weight of an element is that weight which will combine with or that weight which will combine with or displace 8 grams of oxygen or the displace 8 grams of oxygen or the equivalent weight of another element.equivalent weight of another element.

Atomic weight = Equiv. Weight X ValanceAtomic weight = Equiv. Weight X Valance

Many elements have more than one valance.Many elements have more than one valance.

Mole Equivalency in Water Mole Equivalency in Water Treatment Treatment

A mole is the weight in grams of the A mole is the weight in grams of the molecular weight of a substance. molecular weight of a substance. One mole of HOne mole of H22O is equal to 18 grams.O is equal to 18 grams.A mole is a measure that defines how the A mole is a measure that defines how the elements in a substance will combineelements in a substance will combineIn the above equation 2 grams of hydrogen In the above equation 2 grams of hydrogen will combined with 16 grams of oxygen or 1 will combined with 16 grams of oxygen or 1 gram of hydrogen will combine with 8 grams gram of hydrogen will combine with 8 grams of oxygen.of oxygen.

Molar and Molar and Molal Molal Solutions in Solutions in Water ChemistryWater Chemistry

Molar and Molar and Molal Molal solutions are used to solutions are used to determine the concentrations of known determine the concentrations of known compounds in the water.compounds in the water.A molar solution consists of 1 gram molecular A molar solution consists of 1 gram molecular weight dissolved in enough water to make 1 weight dissolved in enough water to make 1 liter.liter.A A molal molal solution consists of 1 gram molecular solution consists of 1 gram molecular weight dissolved in 1 liter of water.weight dissolved in 1 liter of water.

Solutions and StandardsSolutions and Standards

Aqueous Aqueous SolutionSolution

Mixture completely dissolved in waterMixture completely dissolved in water

Standard Standard SolutionSolution

A solution in which the exact A solution in which the exact concentration (molecular weight is concentration (molecular weight is known)known)

StandardizeStandardize Determining the exact strength of Determining the exact strength of solution by comparison with standard solution by comparison with standard of known strengthof known strength

TitrationTitration Process of adding chemical of known Process of adding chemical of known strength to determine concentration strength to determine concentration of unknown compoundsof unknown compounds

Acids and BasesAcids and BasesHydrogen Ions (moles/liter)Hydrogen Ions (moles/liter)

pHpH CompoundCompound Hydrogen IonsHydrogen Ions00 Hydrochloric AcidHydrochloric Acid 101000

11 Stomach AcidStomach Acid 1010--11

22 Lemon JuiceLemon Juice 1010--22

33 VinegarVinegar 1010--33

44 Root BeerRoot Beer 1010--44

55 RainwaterRainwater 1010--55

77 Pure WaterPure Water 1010--77

99 Baking SodaBaking Soda 1010--99

1010 AmmoniaAmmonia 1010--1010

1212 Drain CleanerDrain Cleaner 1010--1212

1313 Sodium HydroxideSodium Hydroxide 1010--1313

Ions in Water TreatmentIons in Water TreatmentAll acids, bases and salts disassociate or ionize in water. ThesAll acids, bases and salts disassociate or ionize in water. These e are known as electrolytes.are known as electrolytes.Electrolytes normally have the same number of protons as Electrolytes normally have the same number of protons as electrons that neutralize one another. When dissolved in water electrons that neutralize one another. When dissolved in water they split into their respective elements or compounds and lose they split into their respective elements or compounds and lose or gain electrons. This results in the elements or compounds or gain electrons. This results in the elements or compounds becoming positively or negatively charged.becoming positively or negatively charged.Sodium and Calcium give up electrons and become positively Sodium and Calcium give up electrons and become positively charged. Positively charged ions are called charged. Positively charged ions are called ““cations.cations.””Chlorine is negatively charged because it gains electrons. Chlorine is negatively charged because it gains electrons. Negatively charged ions are called Negatively charged ions are called ““anions.anions.””

Important Ions in Water Important Ions in Water Chemistry and Common ValencesChemistry and Common Valences

CationsCationsH+H+Na+Na+Ca++Ca++Mg++Mg++MnMn++ or +++++ or +++FeFe ++ or +++++ or +++S ++S ++NHNH44+ +

AnionsAnionsCl Cl ––O O -- --OH OH ––HCOHCO3 3 ––COCO3 3 ----NONO3 3 --SOSO4 4 ––OClOCl --

Use of Aluminum and Iron Salts Use of Aluminum and Iron Salts in Coagulationin Coagulation

COMMON COAGULANT CHEMICALS

Aluminum Sulfate

Al2(SO4)3

Ferric Sulfate Fe 2 (SO4)3

Ferrous Sulfate FeSO4

Ferric Chloride FeCl 3

SodiumAluminate

NaAlO 3

Oxidation Reduction ReactionsOxidation Reduction Reactions

Oxidation or Reduction is a method of forcing Oxidation or Reduction is a method of forcing reactions to completion by the reaction of an reactions to completion by the reaction of an ion with an oxidant or reducing agent.ion with an oxidant or reducing agent.For example, the Cyanide (CN) ion can be For example, the Cyanide (CN) ion can be oxidized with Chlorine to produce Nitrogen oxidized with Chlorine to produce Nitrogen gas and Carbon Dioxide.gas and Carbon Dioxide.Oxidation/reduction reactions will proceed to Oxidation/reduction reactions will proceed to completion. completion.

Oxidation in Water TreatmentOxidation in Water Treatment

Oxidize Inorganic Elements such as Iron and Oxidize Inorganic Elements such as Iron and ManganeseManganeseDestruction of Taste and Odor CompoundsDestruction of Taste and Odor CompoundsDestruction of Synthetic Organic ChemicalsDestruction of Synthetic Organic ChemicalsAssist in the Coagulation Process by Assist in the Coagulation Process by Destabilization of ParticlesDestabilization of ParticlesControl of Biological GrowthControl of Biological Growth

Oxidants Used in Water Oxidants Used in Water TreatmentTreatment

OzoneOzone

PermanganatePermanganate

Chlorine DioxideChlorine Dioxide

ChlorineChlorine

OxygenOxygen

Inorganic and Organic Inorganic and Organic ChemistryChemistry

The study of compounds containing carbonThe study of compounds containing carbonThe most basic compounds are hydrocarbons The most basic compounds are hydrocarbons made up of only carbon and hydrogenmade up of only carbon and hydrogenCarbon can bond with each other forming Carbon can bond with each other forming long chainslong chainsMajor types include alcohols, polymers and Major types include alcohols, polymers and ketonesketonesChlorinated hydrocarbons are of particular Chlorinated hydrocarbons are of particular interest in water treatment interest in water treatment

Organic MeasurementOrganic Measurement

TOCTOC Total Organic CarbonTotal Organic Carbon

NOMNOM Natural Organic MaterialNatural Organic Material

SUVASUVA Specific Specific Ultraviolate Ultraviolate AbsorbanceAbsorbance

PrecursorPrecursor Proportional to the TOC Proportional to the TOC ConcentrationConcentration

Humic SubstancesHumic Substances Products of Natural Products of Natural Vegetative Decay (Color)Vegetative Decay (Color)

Alkalinity/AcidityAlkalinity/Acidity

AlkaliAlkali Soluble Salts that neutralize AcidsSoluble Salts that neutralize Acids

AlkalineAlkaline Sufficient amount of alkali to raise pH Sufficient amount of alkali to raise pH above 7above 7

AlkalinityAlkalinity Capacity of Water to neutralize acidsCapacity of Water to neutralize acids

Does not exist below pH 4.5Does not exist below pH 4.5

AcidicAcidic Condition of Water to lower pH below 7Condition of Water to lower pH below 7

AcidifiedAcidified Addition of Acid to below pH 2Addition of Acid to below pH 2

Water HardnessWater Hardness

Total HardnessTotal Hardness Carbonate and NonCarbonate and Non--CarbonateCarbonate

CarbonateCarbonate Bicarbonate, Carbonate and Bicarbonate, Carbonate and HydroxideHydroxide

NonNon--CarbonateCarbonate Sulfides and ChloridesSulfides and Chlorides

Permanent Permanent HardnessHardness

NonNon--Carbonate HardnessCarbonate Hardness

Natural Natural HardnessHardness

Bicarbonate AlkalinityBicarbonate Alkalinity

Solids and Colloidal MaterialSolids and Colloidal Material

Suspended Suspended SolidsSolids

Suspended in the Water and can be Suspended in the Water and can be Removed by Conventional FiltrationRemoved by Conventional Filtration

ColloidsColloids Finely Charged Particles that do not Finely Charged Particles that do not DissolvedDissolved

Turbidity Turbidity The Cloudy Appearance of Water The Cloudy Appearance of Water caused by Suspended Matter and caused by Suspended Matter and ColloidsColloids

Zeta PotentialZeta Potential Electrical Charge of a suspended Electrical Charge of a suspended particleparticle