WATER PURIFICATION WATER PURIFICATION METHODSMETHODS

PURIFICATION OF WATER PURIFICATION OF WATER On a large scaleOn a large scale On a small scaleOn a small scale

Purpose of water treatment is to Purpose of water treatment is to produce water that is safe and produce water that is safe and wholesome.wholesome.

METHOD OF TREATMENT METHOD OF TREATMENT It depends upon :-It depends upon :-

• Nature of raw waterNature of raw water• The desired standard of water qualityThe desired standard of water quality

Components of water purification Components of water purification systemsystem• Storage Storage • FiltrationFiltration• disinfection disinfection

STORAGESTORAGE Storage is a method of natural Storage is a method of natural

purification. purification. • Physical Physical • Chemical Chemical • Biological Biological

Purification of Water on Large ScalePurification of Water on Large Scale StorageStorage SedimentationSedimentation: preliminary to filtration, : preliminary to filtration,

prevents rapid clogging of filters. Aluminium prevents rapid clogging of filters. Aluminium sulphate (alum): 5-40 mg/Lsulphate (alum): 5-40 mg/L

FiltrationFiltration: removal of 98-99% of bacteria + : removal of 98-99% of bacteria + impuritiesimpurities

Slow sand or biological filtersSlow sand or biological filters: fine sand: fine sand Rapid sand or mechanical filtersRapid sand or mechanical filters: coarse sand: coarse sand

DisinfectionDisinfection: : Physical methodsPhysical methods: boiling, UV radiation, solar : boiling, UV radiation, solar

energy (solar still) etcenergy (solar still) etc Chemical methodsChemical methods: chlorination, ozonation etc: chlorination, ozonation etc

STORAGESTORAGE Reduces suspended impurities 90% in Reduces suspended impurities 90% in

24 Hrs24 Hrs Reduces bacterial count 90% in 5-7 Reduces bacterial count 90% in 5-7

daysdays Optimum storage of river water: 10-14 Optimum storage of river water: 10-14

daysdays Storage for long periods (beyond two Storage for long periods (beyond two

weeks) results in excessive algae weeks) results in excessive algae growth, bad smell and colour to watergrowth, bad smell and colour to water

Copper sulphateCopper sulphate 1-5 kg/5000 m3 (2- 1-5 kg/5000 m3 (2-10 lb per million gallons ) for control of 10 lb per million gallons ) for control of excessive growth of algae.excessive growth of algae.

SLOW SAND FILTERS SLOW SAND FILTERS (cont’d)(cont’d)

Four main elementsFour main elements: : • Water HeadWater Head: a layer of raw water, 1-1.5 : a layer of raw water, 1-1.5

meters deepmeters deep• Sand BedSand Bed: 1 meter thickness, gravel : 1 meter thickness, gravel

support o.30 meter or 30-40 cm deepsupport o.30 meter or 30-40 cm deep• Sand grains diameterSand grains diameter: 0.2-0.3 mm, fine : 0.2-0.3 mm, fine

sand. Top layer easily clogged & top 3-5 cm sand. Top layer easily clogged & top 3-5 cm sand is removed periodically for washingsand is removed periodically for washing

• Drainage system: perforated pipesDrainage system: perforated pipes• Filter control valvesFilter control valves

Chemical coagulants are not usedChemical coagulants are not used

Vital Layer or Zoogleal Layer or Vital Layer or Zoogleal Layer or “Schmutzdecke”or Biological Layer“Schmutzdecke”or Biological Layer

Slimy, gelatinous layerSlimy, gelatinous layer Formed on the top of sand bed, 2-3 cm, Formed on the top of sand bed, 2-3 cm,

2-3 days2-3 days Consists of multiple organisms including Consists of multiple organisms including

bacteria, diatoms, planktons, algae etcbacteria, diatoms, planktons, algae etc Heart of slow sand filterHeart of slow sand filter Removes organic matter, holds back Removes organic matter, holds back

bacteria, free waterbacteria, free water When thick, top layer 2-3 cm scrapped When thick, top layer 2-3 cm scrapped

outout Until the vital layer fully formed, filtrate Until the vital layer fully formed, filtrate

is run to wasteis run to waste

Cross section of slow sand Cross section of slow sand bedbed

vital layervital layer

Sand

Gravel

Water

Filtered water

Stone

SLOW SAND FILTERSLOW SAND FILTER

SECTION OF FILTER BEDSECTION OF FILTER BED

ADVANTAGES OF ADVANTAGES OF SLOW SAND FILTERSLOW SAND FILTER

Simple to construct and operate Simple to construct and operate The cost of construction is cheaper than The cost of construction is cheaper than

that of rapid sand filtersthat of rapid sand filters The physical, chemical and bacteriological The physical, chemical and bacteriological

quality of filtered water is very high when quality of filtered water is very high when working ideally; slow sand filters have working ideally; slow sand filters have been shown to reduce total bacterial been shown to reduce total bacterial counts by 99.9 to 99.99 percent and E. coli counts by 99.9 to 99.99 percent and E. coli by 99 to 99.9 percent. by 99 to 99.9 percent.

VENTURI METERVENTURI METER

This measures the resistance of This measures the resistance of the filtration bed or “loss of the filtration bed or “loss of head” to filtration process.head” to filtration process.

Rapid Sand or Mechanical Rapid Sand or Mechanical FiltersFilters

Two typesTwo types: open gravity type, closed pressure type: open gravity type, closed pressure type Steps: Steps:

• Coagulation:Coagulation: Alum 5-40 mg/L Alum 5-40 mg/L• Rapid mixingRapid mixing: mixing chamber: mixing chamber• FlocculationFlocculation: flocculation chamber for 30 minutes. : flocculation chamber for 30 minutes.

Flocculent precipitate of Aluminium hydroxide, large flocs Flocculent precipitate of Aluminium hydroxide, large flocs that settle more easily. Colloidal + suspended particle + that settle more easily. Colloidal + suspended particle + alum : large flocs (alum-flocs)alum : large flocs (alum-flocs)

• SedimentationSedimentation: sedimentation tanks (2-6 hrs), flocculent : sedimentation tanks (2-6 hrs), flocculent precipitate + impurities + bacteria settle downprecipitate + impurities + bacteria settle down

• Filtration Filtration • Disinfection Disinfection • Note: this conventional treatment is not effective in Note: this conventional treatment is not effective in

the removal of heavy metals & radioactivity. For the removal of heavy metals & radioactivity. For their removal, Absorption on Granular Activated their removal, Absorption on Granular Activated Carbon (GAC filters) may be required.Carbon (GAC filters) may be required.

Flow Diagram Of A Rapid Sand Filtration Plant

CHLORINE

MIXING CHAMBER

FLOCCULATION CHAMBER SEDIMENTATION

TANK

FILTERS CLEAN WATER CONSUMPTION

RIVER

VIEW OF RAPID SAND FILTERVIEW OF RAPID SAND FILTER

FILTER BEDSFILTER BEDS Filtering mediumFiltering medium: sand ( effective size : sand ( effective size

of sand particles 0.4-0.7 mm, coarse of sand particles 0.4-0.7 mm, coarse sand)sand)

Depth of sand bedDepth of sand bed: 1-1.5 feet deep: 1-1.5 feet deep Clogging of filters by suspended Clogging of filters by suspended

impurities and bacteria: Loss of Headimpurities and bacteria: Loss of Head Cleaning by back-washingCleaning by back-washing daily or daily or

weekly for 15 minutesweekly for 15 minutes Compressed airCompressed air

ADVANTAGESADVANTAGES Rapid sand filter can deal with Rapid sand filter can deal with

raw water directly raw water directly No preliminary storage is needed No preliminary storage is needed The filter beds occupy less spaceThe filter beds occupy less space Filtration is rapid, 40 – 50 times Filtration is rapid, 40 – 50 times

that of a slow sand filterthat of a slow sand filter The washing of the filter is easy The washing of the filter is easy There is more flexibility in There is more flexibility in

operation.operation.

COMPARISON OF RAPID AND COMPARISON OF RAPID AND SLOW SAND FILTERSSLOW SAND FILTERS

s. Nos. No Rapid Sand Rapid Sand FilterFilter

Slow Sand Slow Sand Filter Filter

1.1. Space Space Occupies very Occupies very little spacelittle space

Occupies large Occupies large area area

2.2. Rate of Rate of Filtration Filtration

200 m.g.a.d200 m.g.a.d 2-3 m.g.a.d2-3 m.g.a.d

3.3. Effective size Effective size of sand of sand

0.4-0.7 mm0.4-0.7 mm 0.2–0.3 mm0.2–0.3 mm

4.4. Preliminary Preliminary treatment treatment

Chemical Chemical coagulation and coagulation and sedimentation sedimentation

Plain Plain sedimentation sedimentation

5.5. Washing Washing By back-By back-washing washing

By scraping the By scraping the sand bedsand bed

COMPARISON OF RAPID AND COMPARISON OF RAPID AND SLOW SAND FILTERSSLOW SAND FILTERS

s. Nos. No Rapid Sand Rapid Sand FilterFilter

Slow Sand Slow Sand Filter Filter

6.6. OperationOperation Highly skilled Highly skilled Less skilledLess skilled

7.7. Loss of head Loss of head allowedallowed

6 – 8 feet6 – 8 feet 4 feet4 feet

8.8. Removal of Removal of turbidity turbidity

GoodGood Good Good

9.9. Removal of Removal of colour colour

Good Good Fair Fair

10.10. Removal of Removal of bacteriabacteria

98-99 percent98-99 percent 99.9-99.99 99.9-99.99 percentpercent

Water ChlorinationWater Chlorination More than 98% of U.S. supply systems use More than 98% of U.S. supply systems use

chlorine-based disinfectants.chlorine-based disinfectants. The effectiveness of all chemical treatment The effectiveness of all chemical treatment

of water is related to the temperature, PH of water is related to the temperature, PH level and clarity of water.level and clarity of water.

Cloudy water often requires higher Cloudy water often requires higher concentrations of chemical to disinfect.concentrations of chemical to disinfect.

If the water temperature is below (4 degree If the water temperature is below (4 degree centigrade), double the treatment time centigrade), double the treatment time before drinking.before drinking.

Contact time must increase under lower Contact time must increase under lower temperature, or high PH (alkalinity).temperature, or high PH (alkalinity).

Water ChlorinationWater Chlorination Supplement not a substitute to sand filtrationSupplement not a substitute to sand filtration For drinking water, doses varying fromFor drinking water, doses varying from 1 to 4 1 to 4

ppmppm are usually employedare usually employed HH22O + CLO + CL22 = HCL + HOCL = HCL + HOCL Disinfecting action of chlorine mainly due to Disinfecting action of chlorine mainly due to

hypochlorous acidhypochlorous acid PH of waterPH of water = 6.5-8.5. Chlorine acts more rapidly = 6.5-8.5. Chlorine acts more rapidly

in acid water, its efficiency also increases as in acid water, its efficiency also increases as temperature rises.temperature rises.

Not effective if PH of water above 7.2 or below Not effective if PH of water above 7.2 or below 6.86.8

Principles of Chlorination or Principles of Chlorination or Chlorine ProcessChlorine Process

WaterWater: : should be clear, free from turbidity should be clear, free from turbidity (turbidity impedes efficient chlorination(turbidity impedes efficient chlorination))

Estimate chlorine demand of waterEstimate chlorine demand of water: : ( amount ( amount of chlorine needed to destroy bacteria & to of chlorine needed to destroy bacteria & to oxidize all organic matter present in wateroxidize all organic matter present in water

Contact periodContact period: : ½ to 1 hour to kill bacteria & ½ to 1 hour to kill bacteria & virusesviruses

Minimum free residual chlorineMinimum free residual chlorine:: 0.3 0.3 - - 0.5 mg/L 0.5 mg/L or 0.5 ppm, provides a margin of safety or 0.5 ppm, provides a margin of safety against subsequent microbial contamination. against subsequent microbial contamination. At 1 ppm & over taste troublesAt 1 ppm & over taste troubles

Correct dose of chlorineCorrect dose of chlorine: : chlorine demand of chlorine demand of water +free residual chlorinewater +free residual chlorine

Principles of Chlorination – Principles of Chlorination – cont’dcont’d

Never add any solid form of Never add any solid form of chlorine directly to water supply. chlorine directly to water supply. Always make up a paste firstAlways make up a paste first..

Various forms of ChlorineVarious forms of Chlorine Chlorine gasChlorine gas: : chloronomes, chlorine gas chloronomes, chlorine gas

cylinderscylinders Chlorine powder, Bleaching powder or Chlorine powder, Bleaching powder or

WSPWSP: : chlorine content = 33% + quick lime or chlorine content = 33% + quick lime or calcium oxide. Very unstable, chlorine lost due to calcium oxide. Very unstable, chlorine lost due to moisture, COmoisture, CO2, 2, heat, light etc. one teaspoonful = 5 heat, light etc. one teaspoonful = 5 gm of WSP, small safety box = 15 gm of WSPgm of WSP, small safety box = 15 gm of WSP

Chlorine tabletsChlorine tablets: : Puritabs or Halazone tablets: Puritabs or Halazone tablets: one tablet of 5-mg sufficient for 20 litres of waterone tablet of 5-mg sufficient for 20 litres of water

Chlorine Stock solutionChlorine Stock solution: : 3 tablespoons of 3 tablespoons of WSP + 1 liter of water. 3 drops of this solution in WSP + 1 liter of water. 3 drops of this solution in 1 liter of water1 liter of water

One scoopful of WSP when added to 100 gallons One scoopful of WSP when added to 100 gallons of water, is equivalent to a dose of 1 ppm of of water, is equivalent to a dose of 1 ppm of chlorinechlorine..

Methods of ChlorinationMethods of Chlorination Simple ChlorinationSimple Chlorination ChloraminationChloramination Breakpoint ChlorinationBreakpoint Chlorination Super chlorinationSuper chlorination

Simple chlorinationSimple chlorination Chlorine gas or Bleaching Chlorine gas or Bleaching

powderpowder Dose determined by Horrock’s Dose determined by Horrock’s

apparatusapparatus

ChloraminationChloramination Ammonia + chlorine ratio = 1:4 Ammonia + chlorine ratio = 1:4

or 1:5or 1:5 Long action of 2 hoursLong action of 2 hours Germicidal action of 2 hoursGermicidal action of 2 hours Germicidal power less than Germicidal power less than

chlorinechlorine More stable, long actingMore stable, long acting No objectionable odour or No objectionable odour or

tastetaste Swimming poolsSwimming pools

Breakpoint ChlorinationBreakpoint Chlorination Chlorine + natural ammonia = Chlorine + natural ammonia =

chloramineschloramines Destruction of chloraminesDestruction of chloramines BreakpointBreakpoint: : point at which free point at which free

residual chlorine is available residual chlorine is available for continuous disinfectionfor continuous disinfection

FORMATION OF CHLORAMINE

DESTRUCTION OF CHLORAMINE

BREAK POINT

FREE RESIDUAL CHLORINE

BREAK POINT CHLORINATION

Super chlorinationSuper chlorination Addition of excess chlorine than Addition of excess chlorine than

requirement (H+1) (H= dose determined requirement (H+1) (H= dose determined by Horrocks test in scoopfuls + one extra by Horrocks test in scoopfuls + one extra scoop. One scoop = 2 gm or 1 ppm of scoop. One scoop = 2 gm or 1 ppm of chlorine in 100 gallons of waterchlorine in 100 gallons of water

DechlorinationDechlorination: : sulphur dioxide 1:1 or sulphur dioxide 1:1 or sodium thiosulphate 1.8:1 (oxidising sodium thiosulphate 1.8:1 (oxidising agentsagents))

Each one gm of sodium thiosulphate Each one gm of sodium thiosulphate when dissolved in water, will remove 1 when dissolved in water, will remove 1 ppm of chlorine from 100 gallons or 455 ppm of chlorine from 100 gallons or 455 liters of waterliters of water

Super chlorination – cont’dSuper chlorination – cont’d Epidemics, heavily polluted Epidemics, heavily polluted

waterswaters Kills viruses, ova, cysts Kills viruses, ova, cysts Superchlorination provides a chlorine residual of 3-5 Superchlorination provides a chlorine residual of 3-5

mg/L, 10 times the recommended minimum mg/L, 10 times the recommended minimum breakpoint chlorine concentrationbreakpoint chlorine concentration

Retention time: 5 minutesRetention time: 5 minutes Activated carbon filtration removes the high chlorine Activated carbon filtration removes the high chlorine

residual.residual.

Tests For Free ChlorineTests For Free Chlorine Orthotolidine testOrthotolidine test: : 0.1 ml orthotolidine reagent + 0.1 ml orthotolidine reagent +

1 ml water1 ml water. . Yellow colourYellow colour matched with standard matched with standard or colour discs. Reading within 10 secondsor colour discs. Reading within 10 seconds

Orthotolidine – arsenite testOrthotolidine – arsenite test: : modification of OT modification of OT test. Determines free and combined chlorine test. Determines free and combined chlorine residuals separatelyresiduals separately

Starch Iodide testStarch Iodide test: : 3 drops of cadmium iodide and 3 drops of cadmium iodide and starch indicator solution + 5 ml Hstarch indicator solution + 5 ml H22O = O = blue colourblue colour. . Depth of colour increasing with the amount of Depth of colour increasing with the amount of chlorine present. The colour test is carried out at chlorine present. The colour test is carried out at the end of 30 minutes. If a blue colour is the end of 30 minutes. If a blue colour is obtained, the water is fit to drink. If no blue obtained, the water is fit to drink. If no blue colour is obtained, one more scoopful of WSP per colour is obtained, one more scoopful of WSP per 100 gallons must be added to water. After super 100 gallons must be added to water. After super chlorination, colour test can be performed after chlorination, colour test can be performed after 15 minutes. If no blue colour or faint blue colour, 15 minutes. If no blue colour or faint blue colour, dosage insufficient & should be repeated using 2 dosage insufficient & should be repeated using 2 scoopfuls of WSP to each 100 gallons of water.scoopfuls of WSP to each 100 gallons of water.

OZONATIONOZONATION

Ozone is produced on site by the corona discharge of Ozone is produced on site by the corona discharge of high-voltage electricity in to dry air or oxygenhigh-voltage electricity in to dry air or oxygen

Made of oxygen and reverts to pure oxygenMade of oxygen and reverts to pure oxygen Unstable gas Powerful oxidizing agent, disinfectant Unstable gas Powerful oxidizing agent, disinfectant

than chlorinethan chlorine No by-productsNo by-products Strong virucidal effectStrong virucidal effect – – inactivates virus in few inactivates virus in few

secondsseconds Eliminates odour, taste, colourEliminates odour, taste, colour Employed in combination with chlorinationEmployed in combination with chlorination usuallyusually Disadvantage:Disadvantage: ozone cannot be purchased, must be ozone cannot be purchased, must be

generated on-sitegenerated on-site

OZONATION (cont’d)OZONATION (cont’d) Ozone as pretreatment of water is Ozone as pretreatment of water is

used to destroy viruses, bacteria & used to destroy viruses, bacteria & organic compounds (precursors of organic compounds (precursors of trihalomethanes (carcinogens)trihalomethanes (carcinogens)

Dosage: 0.2 – 1.5 mg/LDosage: 0.2 – 1.5 mg/L More than 1000 municipal water More than 1000 municipal water

treatment plants are utilizing treatment plants are utilizing ozonation – oldest plant is in ozonation – oldest plant is in France, working since1906France, working since1906

Drawback of OzonationDrawback of Ozonation: : no residual no residual germicidal effect, expensive, energy germicidal effect, expensive, energy intensiveintensive

Used in Europe and US to reduce the Used in Europe and US to reduce the level of THMs in finished waterlevel of THMs in finished water

Ultraviolet IrradiationUltraviolet Irradiation Uses light, UV rays, to kill Uses light, UV rays, to kill

microorganisms (viruses, microorganisms (viruses, molds & other pathogens)molds & other pathogens)

used in individual or used in individual or institutional systemsinstitutional systems

Water should be free from Water should be free from turbidity or suspended turbidity or suspended impuritiesimpurities

Ultraviolet Irradiation – cont’dUltraviolet Irradiation – cont’d AdvantagesAdvantages: : exposure for shorter exposure for shorter

period, no taste or odour produced, period, no taste or odour produced, no harmful effects, no requirement no harmful effects, no requirement for addition of chemicals, no toxic by-for addition of chemicals, no toxic by-productsproducts

DisadvantagesDisadvantages: : no residual effect, lack of rapid no residual effect, lack of rapid field test for assessing treatment efficiency, field test for assessing treatment efficiency, apparatus / maintenance expensive, does not kill apparatus / maintenance expensive, does not kill giardia, cysts, worms, cloudy or turbid decreases giardia, cysts, worms, cloudy or turbid decreases effectivenesseffectiveness

Purification of water on a small Purification of water on a small scale or Emergency Disinfectionscale or Emergency Disinfection

BoilingBoiling: : rolling boil for 5-10 minutesrolling boil for 5-10 minutes, , kills kills bacteria, viruses, parasites like giardia & bacteria, viruses, parasites like giardia & cryptospordium, concentrates Nitrate cryptospordium, concentrates Nitrate levels.levels.

Bleaching powderBleaching powder: : 33% available 33% available chlorine, dose determined by Horrock’s chlorine, dose determined by Horrock’s Test or 2-3 gm/1000 liter of clear waterTest or 2-3 gm/1000 liter of clear water

Chlorine stock solutionChlorine stock solution : : Add 3 Add 3 tablespoons (33gms) of WSP to one liter tablespoons (33gms) of WSP to one liter of water. Add 3 drops (0.6ml) of this of water. Add 3 drops (0.6ml) of this solution to one liter of water.solution to one liter of water.

Chlorine tabletsChlorine tablets: : Halazone, Puritbas, one Halazone, Puritbas, one tablet in 1 liter of water.tablet in 1 liter of water.

Purification of water on a small scale Purification of water on a small scale or Emergency Disinfectionor Emergency Disinfection

Iodine solution or tablets:Iodine solution or tablets: 2 drops of 2% 2 drops of 2% solution in 1 liter of water or one tablet in solution in 1 liter of water or one tablet in one liter of waterone liter of water

Filtration: Portable Water Filters for Filtration: Portable Water Filters for Emergency Relief : Emergency Relief :

Pasteurization:Pasteurization:

Disinfection of WellsDisinfection of Wells Find the volume of water in a wellFind the volume of water in a well:: Volume (liters)=Volume (liters)= 3.14 x d3.14 x d22x h x x h x

1000/4 whereas d is diameter of 1000/4 whereas d is diameter of well in meters, h is depth of water well in meters, h is depth of water in metersin meters

Find the amount of Bleaching Find the amount of Bleaching PowderPowder required for disinfection by required for disinfection by Horrock’s testHorrock’s test

Dissolve Bleaching powder in water Dissolve Bleaching powder in water bucketbucket

Disinfection of WellsDisinfection of Wells Deliver chlorine solution to Deliver chlorine solution to

waterwater Contact periodContact period: : one hourone hour Test for residual chlorine (o.5 Test for residual chlorine (o.5

ppm)ppm) Wells best disinfected at nightWells best disinfected at night

HORROCKS TESTHORROCKS TEST ““used to determine the used to determine the

smallest dose of Water smallest dose of Water Sterilizing Powder (WSP) in Sterilizing Powder (WSP) in standard scoopfuls needed standard scoopfuls needed to sterilize 455 liters (100 to sterilize 455 liters (100 gallons) of a water sample”gallons) of a water sample”

HORROCKS TESTHORROCKS TEST Contents of Horrocks ApparatusContents of Horrocks Apparatus::

• Six white cupsSix white cups• One black cupOne black cup• Two metal scoopsTwo metal scoops• Seven glass sterilizing rodsSeven glass sterilizing rods• One special pipetteOne special pipette• Two droppersTwo droppers• Cadmium Iodide starch indicator solutionCadmium Iodide starch indicator solution

HORROCKS TEST (cont’d)HORROCKS TEST (cont’d) ProcedureProcedure::

• Prepare stock solution by taking Prepare stock solution by taking one level of scoopful of WSP in one level of scoopful of WSP in black cupblack cup

• Fill six white cups with water to Fill six white cups with water to be testedbe tested

• Add one drop of stock solution to Add one drop of stock solution to first cup, two drops in second first cup, two drops in second cup, 3 drops to third cup & so oncup, 3 drops to third cup & so on

• Stir the water & wait for half an Stir the water & wait for half an hourhour

HORROCKS TEST (cont’d)HORROCKS TEST (cont’d)•Add 3 drops of starch iodide Add 3 drops of starch iodide

indicator solution to each of indicator solution to each of white cupswhite cups

•Development of blue colour Development of blue colour indicates free residual chlorineindicates free residual chlorine

•Dose for super chlorination: Dose for super chlorination: H+1 H+1

HORROCKS TEST (cont’d)HORROCKS TEST (cont’d) One level of scoopful = 2 One level of scoopful = 2

gm = 1 ppmgm = 1 ppm Each white cup capacity Each white cup capacity

= 200 ml= 200 ml