RO Pretreatment System Chemistry

Pressure Filtration

Plant Chemistry

RO Pretreatment System

Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah Saudi Arabia1

Umar Farooq Chemist NOMAC SIWEP 1

RO Pre Treatments SystemWater ChemistryPretreatment System Coagulation Flocculation & SedimentationChemical Handling and safety precautionBiology and Chemistry for FiltrationMicrobiological growth causesCorrosion phenomena Bio foulingUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah2

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At the end of the respective training course, the participants will be able to:Identify the chemical Hazards & how to handle chemical material safely.Now the foundations of Water Quality Control to avoid the scale corrosion and biological growth in the pretreatment system, and to operate the mentioned at max performance.Understand the troubleshooting events to the plant chemistry system.

Vision Water Quality Control will lead all to understand the limitations and international standards as well as increasing the plant availability. Occupational health will maintain within high standards, zero incident. Operational process will maintain highly performance due to plant chemistry troubleshooting.Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah Main Objective

Water ChemistryWater is an excellent solvent and dissolve to varying degree. any thing it comes into contact with it.

Water born impuritiesWater contains some impurities which are

Dissolved inorganic compoundBi Carbonate, Carbonates, Sulphate , nitrates , Chlorides of calcium , magnesium ,sodium and potassium , inorganic Suspended materials, like clay, silt ,sand , soil and metal oxides, These can not be remove by filtration.

Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah5

Dissolve Organic CompoundHumic acid , fulvic acid , tannine , insoluble matter such as dead bacteria and other biological productsDissolve gassesSuch as oxygen , nitrogen , carbon di oxide , sulpher dioxide , ammonia , and hydrogen sulphide absorbed from atmosphere and solid surfaceMicro OrganismSuch as bacteria algae and fungiUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah6


Why Water is UniqueWater is only substance that exist in form of solid , liquid and steamSpecific heat = 1calorie/gramIt expand = 1600 timeThree Isotopes = H , D2O , T2OHeat of fusion = 144Btu / LbsHeat of vaporization = 980 Btu / LbsFreezing Expand = 1/9Depending upon pressure ,its boil with in the temperature = 35-704F*


Properties of WaterIt is chemical compound expressed by the formula H2O.It is formed by two item of hydrogen and one atom of oxygen Due to different electro negativities of hydrogen and oxygen.H20 Molecule is electrically charged .When the other molecule combine with it then will be formed hydrogen bonding Water is the best solvent .It dissolved different substance In it and the process of dissolving Is desolation Model of hydrogen bonds Between modules of water


Sea WaterIt is store house of impurities It contain 3.6% by weight of solids.Normally 75% impurities of sea water are Br, I , So4 , and Ca ,Mg , K , etc.Cat ion and Anion Salts in Sea water Cations Anions Calcium Ca++ Bicarbonate (HCO3-), Magnesium Mg+ + Carbonate (CO32-), Sodium Na+ Sulfate SO42- Iron Fe2+(ferrous) Chloride Cl- Aluminum AI3+ Nitrate NO3- Potassium K+ Fluoride F-


Types of HardnessTemporary Hardness ( Alkaline Hardness )It is due to presence of bicarbonates of calcium and magnesium in water , also called carbonate hardness. It can be removed by boiling and pretreatment processPermanent Hardness(Non Alkaline Hardness )It is due to presence of chlorides , sulphate and nitrate of calcium and magnesium , it can be remove by ion exchange and desalination process


Types of waterRaw waterWater taken from any natural source which is untreatedHard waterIf salt of calcium Ca++and magnesium Mg+ +dissolve in water called hard waterSoft waterIf calcium Ca++and magnesium Mg+ + salt not present in water is called soft waterDami water Water having no ion no mineral salt remove by ion exchange method are called demi water.


Types of waterPretreatment waterWater having no turbidity no color and suspended particle is called pretreatment water Reverse osmosis waterPure water by forcing saline or impure water through a semi permeable membrane acrosswhich salts or impurities cannot pass.Heavy waterWater having deuterium isotope of hydrogen is known as heavy waterPure waterWater having no impurities and having pH =7Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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RO Process flow diagramUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah13

Pretreatment System

In this module we will learn about the Pretreatment process and the individual steps that make up the process; COAGULATION, FLOCCULATION and SEDIMENTATION. We will learn about the various types of equipment and systems available to effect Pretreatment of water, their expected performance and limitations. We will learn about operating procedures and practices to make the Pretreatment process work. We will also learn about monitoring and control practices available to determine how well it is working, as well as troubleshooting the process when it is not performing well.



Water Pretreatment is the removal of suspended solids (microorganisms, dirt, silt, etc.) by settling from a water stream.

Pretreatment is a mechanical/physical process which requires chemical conditioning to enhance pretreatment performanceUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah15


CONTAMINANTS PRESENT IN WATER

Turbidity ..... This is normally in the category of suspended material, but with particle sizes so small as to have an infinite settling rate.Color ..... Particle size again falling into the colloidal or sub colloidal range. Color can also be present in a true solution.Iron and Manganese ..... Only very small amounts found in surface waters, but sometimes large quantities are found in well waters.Oil and Grease ..... Usually expressed as oil or extractable matter (Freon or Hexane)Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah16


CONTAMINANTS PRESENT IN SEA WATER

Hardness ..... Calcium and magnesium salts expressed as CaCO3.

Alkalinity ..... Bicarbonates, carbonates and hydroxides.

Acidity ..... Free mineral acids such as H2SO4 or HCl.

Dissolved Solids ..... Primarily chlorides, sulfates and silica.

Organic matter ..... Expressed as COD or TOC.Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah17


RELATIVE SETTLING VELOCITIES OF SAND and SILT PARTICLES IN STILL WATER

Particle Diameter, mm Order of Magnitude Time Required to Settle 1 Foot

10.0Gravel0.3 Seconds1.0Coarse Sand3 Seconds0.1Fine Sand38 Seconds0.01Silt33 Minutes0.001Bacteria 35 Hours0.0001Clay Particles230 Days0.00001Colloidal Particles63 YearsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah18


Definitions Coagulation - The electrochemical process of neutralization of surface charges (usually negative) to allow small colloidal particles to collide and form larger masses capable of settling or withstanding pressure.Flocculation - The physical process of the formation of larger masses, often enhanced by the addition of long-chain polymeric compoundsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah19


COAGULATION

Coagulation is a process of charge neutralization of finely divided colloidal impurities in water into masses that will settle rapidly and filtered out of this process.Coagulation involves neutralizing the negative charge particle to adhere.For this purpose mixing can be accomplished by in-line static mixers



CoagulationDestabilization of colloids by neutralizing the forces that keep them apart



DefinitionDissolved Solids Organic or inorganic compounds dissolved in water, e.g. salt. Water is a nearly universal solvent. (TDS)Suspended Solids The amount of suspended particulate matter measured milligrams per liter (mg/l = ppm) (TSS)Alkalinity The acid neutralizing capacity of water, mainly sum of HCO3-,CO3=, and OH- concentrationsApparent Color The color in water caused by light absorption at different wavelengths due to the dissolved and suspended materialTrue Color The residual color in water remaining after any suspended material has been removedTurbidity - a measure of the clarity of the water in FTU, JTU, or NTU. It is an expression of the optical property that causes light to be scattered or absorbed rather than transmitted as straight lines through waterAquatic humic substances - heterogeneous, yellow to black, organic materials that include most of the naturally occurring dissolved organic mater Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah22

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Rapid MixStatic mixer No moving partsCreates velocity gradient for mixingRapid dispersion of treatment chemicalsMixing for sweep flocculationHydroxide formation 1- 7 seconds (1-2 seconds warm water) G - 300 - 16000 sec-1, who knows

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FlocculationThe agglomeration, or building up of smaller particles.To form a bigger particle or flock can settleUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah24


FLOCCULATION

Gentle mixing is required to bring the small particles together permitting them to increase in size and settle more rapidly

Coagulant are chemicals used to neutralize the fine particles of suspended mater in water form flock that will settle and can be filter out .Coagulant aid are that chemicals which added along with the coagulants help in larger and better flock formation.eg poly acryl amide.

Poly acryl amide formula



Many factors influence Coagulation and Flocculation; Mixing Time Amount of Solids in the system Velocity Gradient (size vs. shear resistance) TemperatureUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah26


Chemicals Used In Water TreatmentAluminum Sulfate (Alum) Al2 ( So4)2Poly aluminum Chloride (PAC)Ferric Chloride Fecl3Organic Polymers Poly Acryl AmideInorganic/Organic Polymer Blends

Structural Formula of PAC



Chemical reaction of pretreatment systemAl2(SO4)3 + 6NaHCO3 3NaSO4 + 2Al(OH)3+6CO2

Fe2(SO4)3 + 6NaHCO3 3NaSO4 + 2Fe(OH)3+6CO2

2FeCl3+ 3Ca(OH)2 2Fe ( OH )3 + 3CaCl2 Reaction takes place in two steps

FeSO4 + Ca(OH)2 3NaSO4 + Fe ( OH )2 +CaSO4

Fe ( OH )2 + O2 + 2H2O Fe ( OH )3


Chemical reaction of pretreatment systemFeCl3+ H2O Fe(OH)3 + 3 HClFeCl3+ CuCl FeCl2+ CuCl22FeCl3+ 3Ca(HCO3)2 2Fe(OH)3 + 3CaCl2 +7CO22FeCl3+3Ca(OH)2 2Fe(OH)3 + 3CaCl

Different coagulants and Coagulant aid chemicals which are available in market for pretreatment processCoagulantsAmmonium alum Al2 ( SO4)2.Poly aluminum chloride [Al2(OH)nCl6-n]mAluminum Sulphate Al2 (SO4)3Ferric Chloride FeCl3Ferric Sulphate Fe 2( SO4 )3Sodium Aluminates Na2 Al2 SO4


Ferric Hydrolysis Reactions*FeCl3 +3H2O Fe(OH)3 + 3HClFe+++ + H2O FeOH+++ H+FeOH++ + H2O Fe(OH)2+ + H+Fe(OH)2+ + H2O Fe(OH)3 + H+Fe(OH)3 + H2O Fe(OH)4- + H+2Fe++++ 2H2O Fe2(OH)2+++++ 2H+3Fe++++ 4H2O Fe3(OH)4++++++ 4H+Alkalinity neutralization H+ + HCO3 H2O + CO2From Water Quality and Treatment, 4nd Edition, American Water Works Association


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Chemical for PretreatmentCoagulant aidPoly acryl amideMagnesium chloride Mg Cl2Magnesium Sulphate Mg So4Bentonite ( clay )Magnesia

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JAR TESTINGGang stirrer used to simulate plantsFlash mix time and intensityFlocculation time and intensity (slow mix)Settle for 10-15 minutesCoagulants added at start of flash mix timeFlocculants added as start of slow mix timepH adjustment if needed before coagulant for turbidity removal and after coagulant for color removal



RO Pretreatment GoalsR. O. Pretreatment GoalsReduce SDI < 3.0Difficulties with very clean waterConsistent OperationDo not contribute fouling agentsHow to maintain the SystemUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah33

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DMF MonitoringUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah34

Sea water monitoring


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pHpH - The log of the inverse of the hydrogen ion (H-) concentration. The acidity or basicity of water is determined by the amount of H- present.

0714AcidBaseNeutral

Rain Water5

7.58.5Drinking Water

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Range for Ferric CoagulationUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah36

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pH range of different productsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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Water Biology & Chemistry for Filtration38Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah


Source ConditionsPossibly Anoxic or Anaerobic at lower levels reducing conditionsVery high TDS, possible colorpH high but varied Very low turbidityLimited inorganic suspended solidsHigh temperatureSubject to biological growthUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah39

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Source ComponentsBiological materialAlgaeBacteriaProtozoaVirusesColorColloidal solids-

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Inorganic ColloidsClay, Silt and PrecipitatesCharacteristicsSurface chargeElectrical attractionDouble boundary layerEffects of pH


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CoagulationStable Colloidal SuspensionMechanisms of DestabilizationDouble - layer compressionElectrostatic attractionEnmeshmentInterparticle bridgingEffects of pHRestabilizationCoagulation with Ferric Chloride


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CoagulationCharge neutralizationFormation of microflocsAttraction to charged particles---

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Fe(OH)3


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FlocculationCharge neutralization

Fe(OH)3


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FlocculationSweep flocculation


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FlocculationBridging---

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Coagulant Aids - PolymersCationicPrimary coagulantCoagulant aid

NonionicImproved floc retentionFilter aid

AnionicCoagulant aidSludge thickening

Not expected to be used info just for knowledgeUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah47

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Chemical Feed CalculationsConversionsWater 1 meter3 = 1000 liters1 Kilogram per LiterSpecific Gravity (S. G.) = weight of liquid / weight of waterParts Per Million (PPM) = units / million units grams / million gramsthe same as milligrams per liter (mg/l)Chemical Feed RatesLiquidDryUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah48

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FiltrationSurface Straining Depth AdsorptionAdhesionCoagulationFlocculationSedimentationHydraulic shear


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FiltrationMedia agingEffect on attachment of particlesTime and means of developmentEffects of media growthEffects of overgrowth


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Filter OperationSolids accumulationIncreased resistance to flowHigher shear developmentTurbidity breakthroughService run lengthAccumulated timePotential for biological growthHeadloss


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Filter BackwashCleaning actionInterparticle collisionHydraulic shearBackwashWater only washWater with auxiliary washRatesTemperature effectsBed expansion


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Filter BackwashFactors effecting particle movement ShapeSizeSpecific gravityChanges with timeChanges with solidsRate selectionTemperature effectsBed expansion


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My RulesFeed only as much chemical as necessary to achieve the quality goalsFeed enough chemicals to achieve the quality goalsConstantly review the chemistry Allow plenty of time after any change for equilibrium to be achievedTurbidity values can be misleadingCheck as necessary to make sure no biological fouling is developingNever be in a hurry in a water plant.Always refill from the bottomObserve at least one filter backwash per dayUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah54

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Safe Chemical Handling

SAFETYUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

ExposureIn order for a chemical to produce a biological effect, it must first reach a target individual (exposure pathway).Then the chemical must reach a target site within the body (toxicokinetics).Toxicity is a function of the effective dose (how much) of a foreign chemical (xenobiotic) at its target site, integrated over time (how long).Individual factors such as body weight will influence the dose at the target site

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ExposureRoute of Exposure

The route (site) of exposure is an important determinant of the ultimate dosedifferent routes may result in different rates of absorption.Dermal (skin)Inhalation (lung)Oral ingestion (Gastrointestinal)InjectionThe route of exposure may be important if there are tissue-specific toxic responses.Toxic effects may be local or systemic


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ExposureTime of ExposureHow long an organism is exposed to a chemical is importantDuration and frequency contribute to dose. Both may alter toxic effects.Acute Exposure = usually entails a single exposureChronic Exposures = multiple exposures over time (frequency)


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Father of Modern Toxicology Paracelsus1564

All things are poisonous, only the dose makes it non-poisonous.

Dose alone determines toxicityAll chemicalssynthetic or naturalhave the capacity to be toxic

Dose THE KEY CONCEPT in Toxicology59Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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The emerging field of Pharmacogenomics or Toxicogenomics offers the potential to identify and protect subsets of people predisposed to toxicity from chemicals or drugs

Typical Population

Identify People with normal responses

Identify people with different chemical/drug sensitivity

More SensitiveLess Sensitive


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Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah 61 DefinitionsAcids A corrosive chemical that proteinizes upon contact with body tissue and causes immediate pain. Bases A corrosive chemical that does not proteinize upon contact with body tissue and does not cause Immediate pain. Carcinogens - Substances which under favorable conditions through direct or indirect action, either externally or internally, act on healthy cells to cause a metamorphosis and bring about a rapid proliferation of cellular elements and the development of structure abnormalities. Chemical Means any element, chemical compound or mixture of elements and/or compounds

Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah62Compressed Gas Non Flammable materials which have a PSIA greater than 40 at 70*F, or a PSIA greater than 104 at 104*F, or those Flammable materials which have a PSIA greater than 40 at 100*F.Those with sufficiently high toxicity are class A poisons and receive a Poison gas label.All flammable gas, liquefied or non-liquefied and dissolved have flash points below room temperature. Its impossible to avoid forming a flammable mixture if any leaks into the air.

Container Means any bag, barrel, bottle, box, can, cylinder, drum Reaction vessel, storage tank or the like that contains hazardous chemical.

Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah 63Explosive Substances under which certain conditions of shock, temperatureor chemical reaction decompose with violent rapidity, usually releasing large quantities of gasses and heat. Exposure/Exposed Contact with a hazardous chemical in the course of employment through any route of entry (inhalation, ingestion, skin contact or absorption, etc.) and includes potential (e. g., accidental or possible) exposure. Flammable Liquids A liquid whose vapor can form an ignitable mixture with air. The liquid is the fuel, the surrounding atmosphere is the oxidizer. For the mixture to burn an ignition source must be present.

64Are there portions in your workplace that are hazardous?

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COMMON BASES (pH 8-14)

Sodium hydroxide (lye)Sodium Hypochlorite (Bleach)Aqueous ammoniaPotassium hydroxide (Potash)Ammonium hydroxide

CRITERIA FOR STORING CORROSIVE LIQUIDS

Inspect before placing in storageSeparate acids from basesSeparate acids & bases from other materialsUse drip pans under containersUse personal protective equipments (PPE)Use correct dilution sequencesUse approve storage containers65Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

Corrosive MaterialPrecautionsStore acids and bases in separate areasAvoid inhaling these materialsAvoid contact with skin and eyesWear the recommended protective equipment and clothing


HANDLING CORROSIVE LIQUIDS

pH The pH of a liquid is the numerical measure of its relative acidity or alkalinity. The range is from 0 14 with a neutral level expressed as a pH of 7.0Above 7.0 The liquid is more alkaline or basic.Below 7.0 The liquid is more acidic

COMMON ACIDS

Hydrochloric acidHydrofluoric acidNitric acidPhosphoric acidChromic acid67Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

Corrosive MaterialCharacteristicsWill burn eyes and skin on contactWill burn tissues of respiratory tract if inhaled

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CRITERIA FOR HANDLING HIGHLY TOXIC LIQUIDS

Can be extremely toxic to humansPreplanning is critical when using these materialsKnow the adverse health effectsRestrict access to these materialsCarefully review storage requirementsEnsure sufficient training levels achievedUse adequate personal protective equipmentsUse Approve storage containers.

CRITERIA FOR STORAGE STRONG HIGHLY TOXIC LIQUIDS

Inspect containers before placing in storageSeparate for incompatiblesUse Personal protective equipmentsUse approved storage containers


Materials Causing Other Toxic EffectsPrecautionsAvoid inhaling gas or vapoursAvoid skin and eye contactWear the recommended protective equipment and clothingDo not eat, drink or smoke near these materialsWash hands after handling


HANDLING REACTIVE LIQUIDS

Know the adverse health effectsKnow the reactive nature of the materialSeparate from incompatiblesRestrict access to these materialsCarefully review storage requirementsEnsure sufficient training level achievedUse adequate personal protective equipment(PPE)Use approved storage containers.

STORAGE CRITERIA FOR STRONG REACTIVE LIQUIDS

Follow established proceduresInspect before placing in storageSeparate from incompatiblesUse adequate personal protective equipment (PPE)Use approved storage containers.


Dangerously Reactive MaterialCharacteristicsStore away from heatAvoid shock and frictionWear the recommended protective equipment and clothing


STORAGE CRITERIA FOR STRONG SOLID MATERIALS

Inspect containers before placing in storageSeparate from incompatiblesUse mechanical devices to lift heavy bagsUse personal protective equipmentsProtect from contamination in storageUse exhaust ventilationEmpty bags have residual product insideUse approved storage containers.


MANAGEMENT OF HANDLING AND DISPOSAL OF EMPTY CONTAINERS:

Inspect containers for product residualDo not use empty containers as trash cansCheck with environmental managementTriple rinse reusable containersRemember _ Residual Product is hazardous tooFollow local proceduresCheck with supervisor If policy is unclear.74Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

75Personal Protective Equipment (PPE)Eye ProtectionSafety Glasses / Goggles

Face ShieldRespiratory System ProtectionDust maskRespirator with Charcoal FilterGeneral Purpose RespiratorSCBASkin ProtectionApronClosed Shoes / BootsChemical GlovesImpermeable Suite




77The MSDS Material Safety Data Sheet YOUR GUIDE TO CHEMICAL SAFETY

MSDS


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78Product InformationComposition/Information on IngredientsHazards IdentificationFirst Aid MeasuresFire Fighting MeasuresAccidental Release MeasuresHandling and StorageExposure Controls/Personal ProtectionPhysical and Chemical PropertiesStability and ReactivityToxicological InformationEcological InformationDisposal ConsiderationTransport InformationRegulatory InformationOther InformationMaterial Safety Data Sheets (MSDS)


Sodium Hypochlorite UsageSodium Hypochlorite is use for disinfectionThis is also used for disinfection of dual media filters during the process of backwashing

2.Residual chlorine of 0.3-0.5 ppm is to be maintained in the system just before the dosing of SBS

3.Chlorine existing in water as hypochlorus and hypochlorus acid ion ( Hypochlorite ) define as free available chlorine.


ChlorinationHOCl H + OCl Hypochlorous AcidAt the higher pH range as the ratio of Ocl increase as the sterilization effect of chlorine compound decrease.It is practically observed that the sterilization force of Ocl is approximately 20 time less as that of HOCl HOCl has significantly higher effect than Ocl


Chlorine compound Chlorine compound used for sterilization of microorganismChlorine gas Cl2Calcium hypochlorite Ca ( Ocl )2Sodium hypochlorite NaoclCl2 + H2O HOCl +HCLCa (Ocl )2+ H2O HOCl +Ca ( OH )2NaOcl + H2O HOCl + NaOH


Chlorine di oxide5Naclo2 + 4Hcl 4Clo2 +5Nacl +2H20Chlorine di oxide use for potable water disinfection To protect drinking water from disease causing organisms, or pathogensChlorine has been hailed as the savior against cholera (an acute infectious disease of the small intestine),and various other water-borne diseases Chlorine dioxide


Immediately Dangerous To Life or Health Concentrations (IDLHs)National Institute for Occupational Safety and Health( NIOSH )

Substance Original IDLH Value ppmRevised IDLH Value ppmCarbon Mono Oxide15001200Chlorine ( IWPP )3010Chlorine dioxide ( IWEP )1005Chloroform1000500Hydrazine8050Iodine102Ammonia500300Bromine103Nitrogen dioxide5020


Disinfection and oxidationHistory of disinfectionChlorineReactionsGas - Cl2 + H2O HOCl + HCl (^ pH 4)Liquid - NaOCl + H2O HOCl + NaOH(^ pH 6.0) HOCl OCl- + H+ (^ pH 7.5)Mode of action / problemsShock chlorination biological growthDechlorination Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah84

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Chlorine Health Effects Table Bulletin work safe Alberta CH 067-Chemical Hazards

Chlorine Concentration ppmHealth Effect0.03-0.04Range of odor threshold1-3Mid irritation of the eyes, nose and throat3-6Stinging or burring in the eyes, nose and throat, headache, watering eyes, sneezing, coughing, breathing difficulty, bloody nose.5-10Severe irritation of the eyes, nose and respiratory tract10Immediately dangerous to life and health ( IDLH ) Concentration

10-25May be fatal after 30 minutes of exposure.>25Immediate breathing difficulty, build up of fluid in the lungs ( pulmonary edema)possibly causing suffocation and death. Pulmonary edema may be immediate or delayed>1000Fatal after a few breaths


Safety Precaution of ChlorineIt is a very corrosive chemical It causes burns to skin and eyesIt is harmful if ingested, inhaled it may cause skin irritationIf it comes in contact with skin, immediately wash the skin with plenty of waterFlush the eyes if it comes in contact with the eyes


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Chlorine Effect On Respiratory SystemExternal Effect Directly attack to ciliaNa & K pump damageSurfactant damage

Internal EffectGHS activate nephritic factorCapillary damageSensory nerveInterstitiumAbbreviationAlveoliASC AscorbateSurfactant defensive system to prevent shrinkingX Secondary IntermediateIL8 To digest to killUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah87

If inhaled, the person should be immediately removed to fresh air and medical attention should be sought if signs of suffocationEyes should be protectedChlorine is corrosive to metallic materialTo avoid corrosion should be maintain proper dosing


Acute Effects of Chlorine

Tickling of the nose at 0.014 to 0.054(ppm); Tickling of the throat at 0.04 to 0.097 ppm; Tching of the nose and cough, stinging, or dryness of the nose and throat at 0.06 to 0.3 ppm; Burning of the conjunctiva and pain after 15 minutes at 0.35 to 0.72 ppm; Discomfort ranging from ocular and respiratory irritation to coughing, shortness of breath, and headaches above 1.0 ppm. Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah89

Materials Causing Immediate and Serious Toxic EffectsCharacteristicsMay cause immediate death or serious injury if inhaled, swallowed, or absorbed through the skin


Chlorine AdvantagesEconomicalTraditional technologyChlorine kill microorganism by destroying cell wall of the microorganism with there oxidizing forcesUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah91

Chlorine DisadvantagesSlower kill at high pHConsumed by ammonia, sulfides, iron, manganese, & hydrocarbonsVolatile and easily stripped, thus high usage ratesHigh feed rates and residuals can cause higher corrosion ratesPoor control (or slug treatment) leads to degradation of water treatment compounds -- e.g. organic phosphate and tolyltriazoleChlorinated organics, e.g., THMs, are toxic, regulated, and persistent in the environmentUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah92

93REACTIVE burns, explodes or releases toxic vapors if exposed to other chemicals, heat, air or water.


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Sodium Bi Sulphite Na2S2O5

Used as a reducing agent for free chorineAlmost zero for compliance of the membrane tolerance limitThe most common and economical chlorine reducing agent is Sodium bi sulphite. When dissolved in water, sodium bisulfite (SBS) is formed from SMBS Na2S2O5 + H2O 2 NaHSO3SBS then reduces hypochlorous acid according to 2NaHSO3 + 2HOCl H2SO4 + 2HCl + Na2SO4


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Sodium Bi Sulphite Na2S2O5In theory, 1.34 mg of sodium metabisulfite will remove 1.0 mg of free chlorine. In practice, however, 3.0 mg of sodium metabisulfite is normally used to remove 1.0 mg of chlorine. In aqueous solutions, however, sodium bisulfite can oxidize readily when exposed to air. A typical solution life can vary with concentration as follows: Concentration (wt %) Solution life 10 1 week 20 1 month 30 6 monthsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah95

Sodium Bi Sulphite Na2S2O5

When RO membranes are fouled with heavy metals such as Co and Cu, residual SBS (up to 30 ppm) partially converts to oxidants under the presence of excessive oxygen.

SBS dosing amount control must be optimized and oxidation conditions of the concentrate must be monitored by an oxidation-reduction potential (ORP) meter Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah96

Safety and handling OF SBSIt is a fine white granular product with a pungent smell of sulphur dioxide.It may irritate the skin and may cause irritation and burns to the eyes.It reacts with acids to form toxic and irritating sulphur dioxide gas.Immediately wash with plenty of water if sodium bisulphite comes in contact with skinFlush the eyes if it comes in contact with the eyes


Sulphuric acid H2SO4



Safety and handling of H2SO4It is very hazardous in case of skin contact It is very hazardous in case of eye contact of ingestionLiquid or spray mist may produce tissue damage particularly on mucous membranes of eyes, mouth and respiratory tractSkin contact may produce burnsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah99

LAYERS OF THE SKIN

BURNS & SCALDS

TYPES OF BURN


Ferric chloride Fecl3Ferric chloride is used as a coagulant in Reverse Osmosis plant to aid effective filtration in the dual media filterThe use of ferric chloride increases the settling velocity of the suspended solids by flocks formational media filters. Ferric chloride is effective in a wide range of pH Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah101

Safety and handling of Fecl3Ferric chloride is very hazardous in case of skin contact, eye contact, and ingestion.Ingestion may cause damage to the liver. gastric irritation, abdominal pain and diarrhea. Moderately toxic by ingestion.Liquid and spray mist may cause tissue damage particularly on mucous membranes of eye, mouth and respiratory tract.Severe irritant and corrosive to moist or wet skinInhalation of the spray mist may cause severe irritation of the respiratory tractcharacterized by coughing, choking, or shortness of breath.In case of eye contact, immediately flush eyes with plenty of water for at least 15 minutes.Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah102

67Careless handling can cause real problems


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CORROSIVE

FLAMMABLE

POISON

DANGEROUS WHEN WETSPECIAL SYMBOLS helps you recognize the kind of hazard the chemical could present if not properly handled. These are found on labels of containers that have been shipped by truck, rail, or air.Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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Color and number codedlabel system

123DEGREE OF HAZARD0 minimal hazard1 slight hazard2 moderate hazard3 serious hazard4 severe hazardHEALTHFLAMMABILITYREACTIVITY,INSTABILITYSPECIALUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah 107Health HazardsCorrosives/Oxidizers * Injuries to tissue or skinToxics/Flammables/Compressed gasses * Damage to Respiratory SystemExplosives * Over Pressure * Flying Objects

Radioactive * Radiation Sickness * CancerCarcinogens * Cancer

Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah108Container Label InformationSafe Handling/storage ProceduresHealth/Physical Hazard(s)Primary Hazard(s)First aid treatmentManufacturerIdentity

109LABEL DO's

Make sure every container you use has a label.Report missing, dirty, or illegible labels so they can be replaced.Be sure to put labels on portable containers for all hazardous chemical.Read labels before handling containers- and follow their warnings.Ask your supervisor about any label information you dont understand.


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1101) Alert someone else immediately2) Evacuate and barricade the areaIf a chemical spilled on the body: Rinse the affected area with running water for at least 15 minutes, remove contaminated clothing and shoes while rinsing. Call for medical help.

Wear personal protective equipment: Apron, gloves, safety glasses, face shield or respirator, according to the type of the chemical and the amount spilled.5) Absorb the spill using absorbent sleeves and wipes

In Case of a Chemical Spill Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

111Collect all materials into polyethylene Disposal bags. Collect any broken glass with a dustpan and brush and place in a labeled cartonRinse the area and ventilate well until dangerous levels are no longer in the air 8) Remove personal protective equipment and place any disposable items in a polyethylene disposal bag9) Place waste in appropriate, labeled containers10) Replace any equipment that was used In Case of a Chemical Spill Investigate the incident with your supervisor including recommended preventative actionsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

Materials Causing Toxic EffectsCharacteristicsMay cause death or permanent injury following repeated or long-term exposureMay irritate eyes, skin and breathing passages: may lead to chronic lung problems and skin sensitivityMay cause liver or kidney damage, cancer, birth defects or sterility


113In Case of a Hazardous Gas Leak A) Flammable Gas / Toxic Gas: Evacuate the Area Remove sources of ignition and materials that can burn Put on SCBA and protective clothing as necessary Close the cylinder valve. If possible, without risking yourself If you cant - stay in a safe distance, cool cylinders with water spray to prevent ignition, until all gas is released. Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

114B) Fire in gas storage area: Evacuate the area Call the fire department immediately Put on full protective gear Cool cylinders with water spray continuously to prevent explosion of the cylinders Try to prevent the spread of the fire and wait for helpIn Case of a Hazardous Gas Leak Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

INVESTIGATE AND ANALYSEEVERY ACCIDENT


WHAT ARE UNSAFE CONDITIONS???116Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

UNSAFE CONDITIONS:

Unsafe constructionLack of machine guardsInadequate guardingDefective working conditionsPoor layoutOvercrowding in workplaceNo personal protective equipmentUnsafe lightingStorage of hazardous substance117Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

BASIC CAUSES OF ACCIDENTS:

PERSONAL FACTORS:

LACK OF KNOWLEDGE OR SKILLMENTAL OR PHYSICAL DEFECTSIMPROPER ATTITUDE


BASIC CAUSES OF ACCIDENTS:

JOB FACTORS:

UNSAFE CONDITIONSPOOR WORK STANDARDS


SHORT BREAK


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BIOLOGICAL GROWTHCROSSION CAUSES121Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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CorrosionThe destruction of metal by chemical or electrochemical with its Environment is called corrosion


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Battery AnalogyAnodeCathodeElectrical CircuitMetal lost at anodeCorrosione-ElectrolyteAnodeCathodeUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah123

123The corrosion process is just like the operation of a battery. There is an anode and a cathode, and an electrical circuit between them. In the corrosion cell, metal is lost at the anode.Umar Farooq Chemist NOMAC SIWEP

Factors Influencing CorrosionUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah124

124The amount of corrosion or the corrosion rate is affected by numerous factors.Umar Farooq Chemist NOMAC SIWEP

Factors Effecting CorrosionWater Chemistry eg Cl;NH3;S;O2Ammonia increases the corrosion of copper and alloys of copper by complexing the copper present in the protective layer of copper oxide or copper carbonatepH - Optimum pH 6.0 - 9.0Water VelocityErosionImpingementCavitationStress Corrosion CrackingDe alloyingPitting (Under Deposit; H2S; Cl)Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah125

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Base MetalLocalized Pitting AttackWater

OriginalThicknessPitting CorrosionMetal removed at same rate but from a much smaller areaAnode very smallOften occurs under deposits or weak pointsLeads to rapid metal failure


126Localized Pitting CorrosionIn some situations the anode is very small. Even though the metal loss is at the same rate, instead of losing metal from the entire metal surface, it is being removed from a small area.

The only place for the corrosion to go is down into the metal. The result is a deep hole or pit. This type of corrosion occurs under deposits or at weak points in the metal. This type of corrosion is very serious because it results in rapid failure of the metal.Umar Farooq Chemist NOMAC SIWEP

1001005678910Corrosion Rate, Relative UnitspHCorrosion Vs. pHUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah127

127Water pH

The corrosion rate is dramatically affected by the cooling water pH. As the pH drops, the corrosion rate increases. A low pH allows reaction at the cathode to accelerate.Umar Farooq Chemist NOMAC SIWEP

Corrosion Vs. Temperature

Corrosion RateTemperatureIn general, for every 18F in water temperature, chemical reaction rates double.Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah128

128Water Temperature

In general, for every 18 degrees Fahrenheit increase in water temperature the chemical reaction rate doubles. So, as the cooling water temperature increases, the corrosion rate increases.


Methods To Control CorrosionUse corrosion resistant alloys: $Adjust (increase) system pH: ScaleApply protective coatings: IntegrityUse sacrificial anodes: Zn/MgApply chemical corrosioninhibitorsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah129

129As was stated earlier, corrosion cannot be completely stopped. However, there are several things you can do to help control or minimize corrosion. The following methods can be used to help control corrosion.

1. Use corrosion resistant alloys. Once the cooling system is built, this becomes an expensive alternative.2. Adjust system pH. Increasing pH will reduce corrosion rate but will also increase the scaling potential.3. Apply protective coatings. These are generally not very effective because of the rough metal surfaces and difficulty of maintaining the integrity of the coating. Pre-treating system metallurgy with materials such as Nalprep after mechanical or chemical cleaning has been very effective at minimizing corrosion during system start-up.4. Use sacrificial anodes. These pieces of very reactive metal such as magnesium or zinc that are placed in heat exchangers. Since they are more reactive on the galvanic series than the heat exchanger the sacrificial anode will corrode instead of the heat exchanger.5. Apply chemical corrosion inhibitor programs. There are three general classifications for chemical corrosion inhibitors. Anodic inhibitors, cathodic inhibitors, general inhibitors.


Erosion CorrosionCorrosionUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah130

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Corrosion

4Fe 4Fe2+ + 8e-2O2Anode8OH-8e- + 2O2 + 4H2O 8OH-

4H2O

Cathode4Fe2+ + 8OH- 4Fe(OH)2O2 + 4Fe(OH)2 2Fe2O3 + 4H2O

O2


CorrosionFACTORS PROMOTING CORROSION Impurities/inclusion in the metalLocalized stressDiscontinuities in metal surfaceLow pH conditionsLow flow velocitiesDifferences inTemperatureOxygenSalt Concentration (Significantly Effected by Water Borne Deposits)


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MICROBIOLOGICALGROWTHUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah133

133Your cooling system is the ideal environment for microscopic organisms to live and breed. They enter your system from the air or makeup water and find everything they need to survive there. Left uncontrolled they multiply quickly and can completely foul a cooling system in a very short period of time.Umar Farooq Chemist NOMAC SIWEP

Microbiological GrowthWater treatment is about managing three fouling processes...CorrosionScaleMicrobioThe microbial fouling process is...The most complexThe least understoodThe hardest to measure and monitorControlled using the least desirable, most expensive, & potentially hazardous productsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah134

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2


BacteriaSears Tower

Bacteria extremely smallCompared to a human, a bacteria is like a grain of sand to the Sears TowerSize allows many (millions) to fit into a small volume of water...


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8

Two factors that make controlling bacteria a challenge are:

SIZENUMBERUmar Farooq Chemist NOMAC SIWEP

Types of BacteriaUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah136

1361. Bacteria are the most dangerous microorganisms in cooling water because they can cause the most damage.


Bacteria

Slime FormersIron DepositingAnaerobicTypical RodsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah137

137There are four classifications of bacteria. All four thrive in cooling water but because of their differing needs, they live in different parts of the system.

Slime Forming Bacteria: Upper RightSlime forming bacteria are the sticky, jelly-like organisms that grow in tower basins and heat exchangers. They secrete a jelly-like substance to protect their bacteria colony. This sticky layer makes them difficult to destroy and also provides an ideal spot for other materials to become trapped. These bacteria can cause serious fouling problems in a very short time.

Anaerobic Corrosive Bacteria: Lower LeftThese are the most dangerous microorganisms. Anaerobic means they can exist without oxygen. They grow under other deposits where they are sheltered from oxygen in the water. A popular place for them to grow is under deposits of slime forming bacteria. Anaerobic corrosive bacteria takes nutrients, such as sulfate, and convert it into a corrosive acid. These acids can eat right through cooling system metal.

Iron Depositing Bacteria: Lower RightIron depositing bacteria use dissolved iron found in well water as their natural food. They turn this iron into a heavy reddish-brown deposit. The microorganisms can enter your cooling system with the raw makeup water from wells. The deposits they create cause fouling problems and are an ideal shelter for anaerobic corrosive bacteria.

Nitrifying BacteriaThis dangerous organism converts ammonia into nitric acid which lowers the pH of the cooling water and causes corrosion. They need a source for ammonia in the water and are most often found in ammonia plants or breweries.

Denitrifying BacteriaThese microorganisms are most frequently observed in closed cooling systems using nitrite-based corrosion inhibitors. They reduce nitrite and nitrate to nitrogen and ammonia. This process only occurs under anaerobic conditions and is responsible for excessive losses of nitrite corrosion inhibitor.Umar Farooq Chemist NOMAC SIWEP

Microbiology

The most prevalent problems in Pre-treatment water systems are related to microbiology

ProteinsPhospholipidsHydrophilic groupsHydrophobic groupsPhospholipid molecules

GlycocalyxOuter Membrane

DNAPeriplasmicSpace

Flagellum

Cell Membrane

CytoplasmProteinsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah138

138Nalco maintains a Salesman's Help Desk, and microbial control is the most frequently discussed topic of the questions. Even scale and fouling problems are, in the end, biologically induced. For a chemical program to be a success, the microbiology must be controlled. Microbes will eat the scales inhibitors - they will create gelatinous masses which plug strainers and inhibit heat transfer. They are negatively charged, and will absorb zinc corrosion inhibitors. Some are pathogens (adversely affect humans), and can lead to respiratory ailments, or even death (legionella).Umar Farooq Chemist NOMAC SIWEP

Biohazardous Infectious MaterialCharacteristicsContact with microbiological agents (e.g., bacteria, viruses, fungi and their toxins) may cause illness or death


Biohazardous Infectious MaterialPrecautionsWear the recommended protective equipment and clothingWork with these materials in designated areasDisinfect area after handlingWash hands after handling


Basic Growth Requirements

Inorganic NutrientsFood SourceGaseous ElementTemperaturepHInteraction with other MicroorganismsBio FoulingUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah141

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FoulingFOULING is the accumulation of solid material, other than scale, in a way that hampers the operation of equipment or contributes to its deterioration142Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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FoulingFactors which influence fouling are:

Water CharacteristicsWater TemperatureWater Flow VelocityMicrobiological GrowthCorrosionProcess ContaminationEnvironmental (i.e. atmospheric pollutants)Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah143

Bio FoulingTypes of Microorganisms

BACTERIA - need/ do not need OxygenAerobic - Slime and Spore formerAnaerobic - SRB, Clostridia, etc.Iron bacteria - GallionellaNitrification - Nitrosomas, NitrobacterALGAE - need light, food sourceFUNGI - destroys wood, reinforces depositsPROTOZOA - feed on bacteria/algaeUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah144

Slime and there preventionSlime occurs to gather with corrosion and scaleSlime is caused by the adhesion and accumulation of soft muddy material.It formed by mixing micro Organism like bacteria , fungi , algae .It grow by utilizing the dissolved nutrient in water with inorganic mater like mud , sand, and dirtUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah145

SlimeSlime146Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah

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Microbiologically induced Under Deposit Corrosion

1. Bioactivity generates CO2 and/or H2S which lowers the pH underneath the Deposit

2. Iron Corrodes and tubercle grows as pitting corrosion develops12Bio FoulingUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah147

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To Prevent Corrosion


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Bio Fouling ControlGeneral Methods for Bio Fouling ControlPrevent contact with direct sunlight wherever possibleDisinfect make-up waterRegularly maintain and disinfect filtersApplication of BiocidesUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah149

Economic Impact of FoulingDecreased plant efficiencyReduction in productivityProduction schedule delaysIncreased downtime for maintenanceCost of equipment repair or replacementReduced effectiveness ofchemical inhibitorsUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah150

150The affects of the formation of deposits can be summarized as in the slide.Umar Farooq Chemist NOMAC SIWEP

Preventing FoulingPreventionGood control of makeup PretreatmentGood control of corrosion, scale, & microbiology growthReductionIncrease backwashing frequency Side stream filterOngoing ControlBack flushing, Air rumblingChemical treatmentUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah151

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Charge Reinforcement MechanismSlightly anionicsuspended particleSuspended Solidwhich has adsorbedhighly anionic chemicalHighlyAnionicChemicalAnionic polymers increase strength of charge already present on suspended solidsKeep particles small enough so they do not settle outUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah152

152Charge ReinforcersAnionic polymers that increase the strength of the already present charge on suspended solids. This keeps the particles small enough that they will not settle out.


Fouling Control Charge Reinforcement Dispersants:adsorb onto particles, creating very highly charged surfaces, which repel each other because of like charges.+

+Fe(OH)2+Fe(OH)2+Fe(OH)3o+++

Fe(OH)2+Fe(OH)3o

Fe(OH)2+

FoulingUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah153

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Notes:_______________________________________________________________

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OXIDIZING BIOCIDESUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah154

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Oxidizing BiocidesPenetrate microorganisms cell wall and burn-up the internals of the organismEffective against all types of bacteriaNo microorganism resistant to oxidizersKill everything given sufficient concentration levels & contact timeUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah155

155Oxidizing Biocides are one of three classes of chemicals used to control microbiological populations. Non-oxidizing biocides and biodispersants are the other two classes.

Oxidizing biocides work by penetrating the microorganisms cell wall and oxidizing or burning up the internals of the organism.

Oxidizers are effective against all types of microorganisms commonly found in cooling systems. This includes bacteria, fungi and algae. No microorganism is resistant to this oxidation process. Oxidizers, at sufficient levels, kill any microorganism they contact.

When added to the cooling water, oxidizing biocides react with certain contaminants present in the water. The most common contaminants are ammonia and hydrocarbons, as well as, microorganisms. These contaminants affect the performance of the oxidizing biocide because they consume the biocide. The amount of contaminants that react with the oxidant is called the oxidant demand. It is the presence of free available oxidant that provides satisfactory microbio control. It is necessary to maintain a prescribed level of free available oxidant for good control.

One of the limitations of the oxidizing biocides is that they only kill the microorganisms they contact. Microorganisms that grow under deposits or inside wood supports in cooling towers will not be affected by oxidizing biocides.Umar Farooq Chemist NOMAC SIWEP

Oxidizing BiocidesBroad-spectrum effectiveness makes oxidizers primary biocide in large cooling water applicationsOxidizersGas ChlorineBleachActi-BromBCDMHStabilized BromineUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah156

156Chlorine and bromine based chemicals are the most widely used oxidizing for cooling systems. Ozone is also in this class. The use of gaseous chlorine has decreased recently due to plant safety concerns and government regulations. All biocides are regulated by the Environmental Protection Agency (EPA).


Oxidizing BiocidesBiocide effectiveness pH dependentCl2 HOCl & OCl-Br HOBr & OBr-HOCl/HOBr Biocidal@ pH=8.0HOCl: 22%HOBr: 83%Bromine more biocidalHOCl or HOBr

0102030405060708090100456789101112pH010203040506070100OCl- or OBr-

HOCl

HOBr8090Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah157

157Bromine much more biocidal at pH > 7.5There is a much higher % of HOBr, the active biocidal species, than HOCl


Before BiodispersantAfter BiodispersantBiodispersantsDo not kill -- Penetrate deposits and increase the effectiveness of oxidizing & non-oxidizing biocides.Umar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah158

158Biodispersants are an important component of a successful microbio control program. Biodispersants do not kill microorganisms, but they allow biocides to penetrate more efficiently. They also breakup biodeposits, which allows them to be killed more effectively by biocides. Biodispersants increase the effectiveness of biocide programs.

Biodispersants are an important component of a successful microbio control program. As stated already, oxidizing biocides can only kill what they contact. Biodispersants do not kill microorganisms, but they allow biocides to penetrate more effectively. They also breakup biodeposits, which allows them to be killed more effectively by biocides.Umar Farooq Chemist NOMAC SIWEP

Monitoring & ControlFreeorTotalPillowSample

DPD

DR5000SpectrophotometerorColorWheelppmOxidantResidual(as Cl2)

Oxidant Determination TestDiethyl Phenylenediamine (DPD)Bio Fouling MonitoringUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah159

159The purpose of adding a biocide to a cooling water system is to control microbial growth. Measuring the levels of microbial growth is, therefore, a valid control test. this can be done with dip slides of EASICULTSTM, ATP testing or plates.Umar Farooq Chemist NOMAC SIWEP

BENEFITSRapid Program Adjustment To Maintain Optimum PerformanceDetermine The Most Effective Biocide ProgramMaximize Cost-PerformanceMaximize Technical ResultsMinimize Environmental Impact

COSTPERFORMANCEENVIRONMENT

TRA-CIDEBio Fouling Monitoring


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Any QUESTIONThanks 4ur Attention



Shuaibah IWEP III RO EXPANSION


THANK YOUUmar Farooq Senior Chemist NOMAC SIWEP Shuaibah Jeddah163


Sheet: TurbidityHeadloss

Shuaibah IWEP III RO EXPANSION

Name & ID____________________

Written Check Plant Chemistry (RO Pretreatment System)

Date: 12-11-2012

Time: 20 min

Marks: 20 Note: 1) General portion of the paper has to be attempted by all trainees.

General Chemistry Q 1) Select the appropriate answer.

(15 marks)

i. How many chemical used in pretreatment system. H2S04 Fecl3 Polydactyl amide All of the above

ii. The neutral pH of water represent by 10 5 7 None of the above

iii. Danger range of chlorine is

5 ppm 18 ppm

25 ppm

iv. Water contains some impurities which are Dissolved inorganic compound

Dissolve Organic Compound

Dissolve gasses

Micro Organism

All of the abovev. Settling time of bacteria in the water is 30 minutes 1 hrs 12 hrs 35 hrs

vi. Ferric chloride ( Fecl3 ) used for pretreatment process as a Coagulant aid Coagulant Cationic Coagulant All of abovevii. Factor infusing corrosion

pH

Temperature

Dissolved Solids

Microbiological Growth

All of above

viii. The destruction of metal by mechanical is called

Corrosion

Erosion

Pitting Corrosion

Non of above

ix. Water is only substance that exist in three state

------------------------------------

------------------------------------

------------------------------------

x. How many types of hardness write name

--------------------------------------------

--------------------------------------------

xi. sources of water write any five name of

--------------------------------------------

--------------------------------------------

--------------------------------------------

--------------------------------------------

-------------------------------------------xii. Coagulation is the 1st process of pretreatment system true / falls

xiii. Pretreatment chemical process are three step process true / falls

xiv. is the symbol of hazards true / falls

xv. is the symbol of corrosive true / falls

Q 1) Pick up the correct answer:

(5 marks)

i. Hypochlorite use for __________ ( Disinfection , Infection )

ii. The MSDS Stand for _____________(Material safety data sheet , material safely demand sheet)

iii. PPE Stand for ________ (Personal power equipment , Personal protective equipment )

iv. For neutralization of chlorine used________(Sodium meta bi sulphite , Antiscalent )

v. H2SO4 Skin contact may produce _________ ( burn , smell )

i. Water is only substance that exist in three state

------------------------------------

------------------------------------

------------------------------------

ii. How many types of hardness write name

--------------------------------------------

--------------------------------------------

iii. sources of water write any five name of

--------------------------------------------

--------------------------------------------

--------------------------------------------

--------------------------------------------

-------------------------------------------

iv. Coagulation is the process of pretreatment system true / falls

v. Pretreatment process three step process true / falls

vi. is the symbol of hazards true / falls

vii. is the symbol of corrosive true / falls

Q 1) Pick up the correct answer:

(5 marks)

i. Hypochlorite use for __________ ( Disinfection , Infection )

ii. The MSDS Stand for _____________(Material safety data sheet , material safely demand sheet)

iii. PPE Stand for ________ (Personal power equipment , Personal protective equipment )

iv. For neutralization of chlorine used________(Sodium meta bi sulphite , Antiscalent )

v. H2SO4 Skin contact may produce _________ ( burn , smell )

i. Water contains some impurities which are

Dissolved inorganic compound

Dissolve Organic Compound

Dissolve gasses

Micro Organism

All of the above

ii. Settling time of bacteria in the water is

30 minutes

1 hrs

12 hrs

35 hrs

iii. Ferric chloride ( Fecl3 ) used for pretreatment process as a

Coagulant aid

Coagulant

Cationic Coagulant

All of above

iv. Factor infusing corrosion

pH

Temperature

Dissolved Solids

Microbiological Growth

All of above

v. The destruction of metal by mechanical is called

Corrosion

Erosion

Pitting Corrosion

Non of above

RO Pretreatment System Chemistry

Technology

Transcript of RO Pretreatment System Chemistry