الرحيم الرحمن الله الرحيم بسم الرحمن الله بسم

PURIFICATION OF WATERPURIFICATION OF WATER It is of great importance for promoting It is of great importance for promoting

health health and preventing disease. and preventing disease. Purpose of water treatment, is Purpose of water treatment, is To produce water that is safe and To produce water that is safe and

wholesome. wholesome. Ground water (e.g., wells and springs) may Ground water (e.g., wells and springs) may

need no treatment, other than disinfection, need no treatment, other than disinfection, surface water (e.g., river water) which surface water (e.g., river water) which tends to be turbid and polluted, requires tends to be turbid and polluted, requires extensive treatment. extensive treatment.

Components of water purification system Components of water purification system are Storage, Filtration and Disinfection.are Storage, Filtration and Disinfection.

Methods of Water PurificationMethods of Water Purification

Water purification is done on small Water purification is done on small scale at domestic level and large scale at domestic level and large scale.scale.

Methods of PurificationMethods of Purification Natural methods of purificationNatural methods of purification Man –made methods of purificationMan –made methods of purification

NATURAL METHODS OF PURIFICATIONNATURAL METHODS OF PURIFICATION

The natural methods by which water is purified The natural methods by which water is purified are:-are:-

DilutionDilution SedimentationSedimentation OxidationOxidation AerationAeration Ultraviolet raysUltraviolet rays Action of Aquatic plants and animalsAction of Aquatic plants and animals Action of sunlight Action of sunlight Some measure of disinfection is accomplished Some measure of disinfection is accomplished

by exposure to sun light provided that there is by exposure to sun light provided that there is time for biochemical stabilization of organic time for biochemical stabilization of organic matter and destruction of microorganisms.matter and destruction of microorganisms.

Purification on small scalePurification on small scale

Boiling (5 to 10 minutes kills off most microorganisms andBoiling (5 to 10 minutes kills off most microorganisms and

removes temporary hardness)removes temporary hardness)

Distillation:Distillation: By this method get rid of all impurities By this method get rid of all impurities

Chemical Disinfection:Chemical Disinfection:

Chlorine solution (small quantity of 5% bleaching Chlorine solution (small quantity of 5% bleaching powder solution is sufficient for chlorination of water)powder solution is sufficient for chlorination of water)

Chlorine tablets ( 1 tablet is required for 1 liter of Chlorine tablets ( 1 tablet is required for 1 liter of water)water)

Iodine ( 2 drops of 2% solution of iodine is required Iodine ( 2 drops of 2% solution of iodine is required for 1 liter of for 1 liter of water) water)

Potassium permanganate (a little amount giving pink Potassium permanganate (a little amount giving pink coloration)coloration)

Alum ( .1 to .4 gram is required for 5 liters of water)Alum ( .1 to .4 gram is required for 5 liters of water)

Three pot domestic filtration: Three pot domestic filtration:

FILTERATIONFILTERATION

Filtration systems are of two typesFiltration systems are of two types SLOW SAND OR BIOLOGICAL FILTERSSLOW SAND OR BIOLOGICAL FILTERS Elements of a slow sand filterElements of a slow sand filter

Essentially these consist of, supernatant (raw) Essentially these consist of, supernatant (raw) water, a bed of graded sand, an under – drainage system; water, a bed of graded sand, an under – drainage system; and a system of filter control valvesand a system of filter control valves

Supernatant waterSupernatant water 1 to 1.5 meter1 to 1.5 meter Sand bedSand bed 1.2 meters1.2 meters Gravel supportGravel support 0.3. Meter0.3. Meter Filter bottomFilter bottom 0.16 meter0.16 meter

Vital LayerVital Layer

It develops in first few days and consists of threadlike It develops in first few days and consists of threadlike algae. It removes organic matter and holds back bacteria.algae. It removes organic matter and holds back bacteria.

RAPID SAND OR MECHENICAL FILTERSRAPID SAND OR MECHENICAL FILTERS

The raw water is first treated with a chemical The raw water is first treated with a chemical such as alum, the dose of which varies from 5-such as alum, the dose of which varies from 5-40mg or more per liter, depending upon the 40mg or more per liter, depending upon the turbidity, the gentle stirring results in the turbidity, the gentle stirring results in the formation of a thick, flocculent precipitate of formation of a thick, flocculent precipitate of AloH. These are removed by sedimentation and AloH. These are removed by sedimentation and rapid sand filters.rapid sand filters.

SURVEILLANCE OF DRINKING WATER QUALITYSURVEILLANCE OF DRINKING WATER QUALITY Sanitary survey:Sanitary survey: Sanitary survey is an on-the-spot inspection and Sanitary survey is an on-the-spot inspection and

evaluation by a qualified person of the entire water evaluation by a qualified person of the entire water supply system. The purpose of the survey is detection supply system. The purpose of the survey is detection and correction of faults and deficiencies. A sanitary and correction of faults and deficiencies. A sanitary survey is essential for adequate interpretation of survey is essential for adequate interpretation of laboratory results.laboratory results.

Sampling:Sampling: Sampling of water should be done with the thoroughness Sampling of water should be done with the thoroughness

of a surgical operation, with the observation of similar of a surgical operation, with the observation of similar aseptic precautions, it depends upon the results of aseptic precautions, it depends upon the results of analysis. It should be carried out by competent and analysis. It should be carried out by competent and trained personnel.trained personnel.

Bacteriological surveillance:Bacteriological surveillance: The tests usually employed in water bacteriology are The tests usually employed in water bacteriology are

presumptive coliform test .Tests for the detection of presumptive coliform test .Tests for the detection of faecal streptococci and Cl. Perfringens is also done. A faecal streptococci and Cl. Perfringens is also done. A complete bacteriological examination consists of all complete bacteriological examination consists of all these tests. these tests.

Examination of WaterExamination of Water

Before water from any source is Before water from any source is declared fit for human consumption, declared fit for human consumption, it is essential to take the sample and it is essential to take the sample and carry out the following examinations.carry out the following examinations.

Physical examinationPhysical examination Chemical examinationChemical examination Bacteriological examination.Bacteriological examination.

Informations required for samplingInformations required for sampling The following information should be The following information should be

furnished along with the sample of water.furnished along with the sample of water. Source of water supplySource of water supply Geological formation of the soil if availableGeological formation of the soil if available In case of well, its depth, diameter and In case of well, its depth, diameter and

how it is used.how it is used. Any suspected source of pollution in the Any suspected source of pollution in the

vicinity.vicinity. Whether any method of purification is Whether any method of purification is

used.used.

Sample CollectionSample CollectionSampling from the stream:Sampling from the stream:

Water is taken from the middle of a Water is taken from the middle of a stream. stream. With the mouth of the bottle facing With the mouth of the bottle facing upstream, lower the bottle into the upstream, lower the bottle into the stream and allow to fill. Tilt bottle stream and allow to fill. Tilt bottle upwards to fill completely, the cap is upwards to fill completely, the cap is carefully screwed back, taking care not carefully screwed back, taking care not to touch the screw thread at the top of to touch the screw thread at the top of the bottle, nor the inside of the cap.the bottle, nor the inside of the cap.

Sampling from a WellSampling from a Well

Tie a sample bottle on to a weighted Tie a sample bottle on to a weighted length of a rope or strong string. Use a length of a rope or strong string. Use a stone or piece of metal weighing about stone or piece of metal weighing about 500g as the weight and attach the 500g as the weight and attach the bottle just above it. After removing the bottle just above it. After removing the cap aseptically, lower the bottle into cap aseptically, lower the bottle into the well to a depth of about 1 m. when the well to a depth of about 1 m. when no more air bubbles rise to the no more air bubbles rise to the surface, raise the bottle out of the well surface, raise the bottle out of the well and carefully replace the cap.and carefully replace the cap.

Sampling from a tapSampling from a tap Flame a tap till it is red hot to ensure Flame a tap till it is red hot to ensure

that it is sterilized, from the inside. that it is sterilized, from the inside. Turn the tap full on and allow the Turn the tap full on and allow the water to run to waste for one minute. water to run to waste for one minute. Close the tap until only a slow trickle Close the tap until only a slow trickle of water is coming out and fill the of water is coming out and fill the sampling bottle. Carefully replace sampling bottle. Carefully replace cap.cap.

Water Quality – Criteria and StandardWater Quality – Criteria and Standard

The guideline for drinking water The guideline for drinking water quality recommended by WHO quality recommended by WHO (1993 and 1996) relate to following (1993 and 1996) relate to following variables:variables:

Acceptability aspectsAcceptability aspects Microbiological aspectsMicrobiological aspects Chemical aspectsChemical aspects Radiological aspectsRadiological aspects

Acceptability AspectsAcceptability AspectsPhysicalPhysical

Constituents or Constituents or characteristicscharacteristics

Acceptability Acceptability AspectsAspects

Physical parametersPhysical parameters ColourColour Taste and odourTaste and odour TemperatureTemperature TurbidityTurbidity

Appearance Appearance Should be acceptableShould be acceptableShould be acceptableShould be acceptableShould be acceptableShould be acceptableNo turbidityNo turbidity

Acceptability AspectsAcceptability AspectsChemicalChemical

Inorganic constituentsInorganic constituents EffectsEffects

AluminiumAluminium AmmoniaAmmonia ChlorideChloride Copper, Iron, ManganeseCopper, Iron, Manganese HardnessHardness Hydrogen sulfideHydrogen sulfide Dissolved oxygenDissolved oxygen pH valuepH value

Sodium Sodium sulfatesulfate Total dissolved solidsTotal dissolved solids ZincZinc

Depositions, discolorationDepositions, discoloration

Odour and tasteOdour and tasteTaste, corrosionTaste, corrosionStaining of laundry and sanitary ware Staining of laundry and sanitary ware High hardness: scale deposition, scum formation; low High hardness: scale deposition, scum formation; low hardness; possible corrosion odour and tastehardness; possible corrosion odour and tasteOdour and tasteOdour and tasteGuideline value 0.5 mg/L.Guideline value 0.5 mg/L.Low pH: corrosion; high pH: taste, soapy feel Low pH: corrosion; high pH: taste, soapy feel preferable < 8.0 for effective disinfection with preferable < 8.0 for effective disinfection with chlorine chlorine TasteTasteTaste, corrosionTaste, corrosionTasteTasteAppearance, tasteAppearance, taste

Microbiological Aspects Microbiological Aspects OrganismsOrganisms Guideline valueGuideline value

All water intended for drinkingAll water intended for drinkingE.coli or thermo tolerant coli formE.coli or thermo tolerant coli formbacteriabacteriaTreated water entering the distributionTreated water entering the distributionsystemsystemE.coli or thermo tolerant coli formE.coli or thermo tolerant coli formbacteriabacteriaTotal coli form bacteriaTotal coli form bacteriaTreated water entering the distributionTreated water entering the distributionsystemsystemE.coli or thermo tolerant coli formE.coli or thermo tolerant coli formbacteriabacteriaTotal coli form bacteriaTotal coli form bacteria

Must not be detectable in any 100 mlMust not be detectable in any 100 mlsamplesample

Must not be detectable in any 100 mlMust not be detectable in any 100 mlsample. In the case of large supplies, wheresample. In the case of large supplies, wheresufficient samples are examined, must notsufficient samples are examined, must notbe present in 95% of samples takenbe present in 95% of samples takenthroughout any 12-month period.throughout any 12-month period.

CHEMICAL ASPECTSCHEMICAL ASPECTS

Iodine deficiencyIodine deficiency GoiterGoiter

Excess FluorideExcess Fluoride Dental flourosisDental flourosis

Fluoride deficiencyFluoride deficiency Dental cariesDental caries

Excess inorganic saltExcess inorganic salt DiarrheaDiarrhea

CadmiumCadmium Gastric upsetsGastric upsets

SodiumSodium HypertensionHypertension

SulfatesSulfates Laxative effectLaxative effect

Nitrates and nitritesNitrates and nitrites MethaemoglobinaemiaMethaemoglobinaemia

Typical Non infectious diseases associated with Typical Non infectious diseases associated with water supply (Heavy Metals)water supply (Heavy Metals)

LeadLead Lead poisoningLead poisoning

ArsenicArsenic Black foot diseaseBlack foot disease

ArsenicArsenic Skin and lung cancerSkin and lung cancer

CadmiumCadmium Itai-itai diseaseItai-itai disease

CadmiumCadmium NephropathiaNephropathia

MercuryMercury Minimata diseaseMinimata disease

MercuryMercury NephropathiaNephropathia

Radiological AspectsRadiological Aspects There are two types:There are two types:

1.1. Somatic effectsSomatic effects

Any exposed individual manifest the Any exposed individual manifest the radiological effects these are called radiological effects these are called somatic effects e.g., development of somatic effects e.g., development of carcinomas.carcinomas.

22. Hereditary effects:. Hereditary effects:

The pregnant ladies manifest the The pregnant ladies manifest the radiological effects in the growing fetus radiological effects in the growing fetus in the form of hereditary changes.in the form of hereditary changes.