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Ensuring Safe and Wholesome Water: Dr. Zia-Ul-Ain Sabiha

Learn about the importance of safe and wholesome water for human consumption. Discover the sources of water, types of contamination, water-borne diseases, and methods of purifying water at a domestic level.

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Ensuring Safe and Wholesome Water: Dr. Zia-Ul-Ain Sabiha

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  1. WATER Dr Zia-Ul-AinSabiha

  2. Introduction • Water is essence of life but not all water is safe for consumption • Only safe and wholesome water is safest for human consumption • If water does not meet the criteria of safe and whole some water ,it is considered to be contaminated or polluted.

  3. Safe and Wholesome Water • Is the water that is • Free from pathogenic agents • Free from harmful chemical substances • Pleasant to taste ,i.e free from color and order • Usable for domestic purpose

  4. Potable water • Coliform count upto 5000/100ml and turbidity of upto 10 units is good. • Over 20,000/100ml and turbidities that exceed 250 units is very poor for treating to potable water.

  5. Uses of water • Domestic use • Drinking , cooking washing and bathing ,flushing of toilets and gardening etc • Public purposes • Cleaning streets, recreational purposes like swimming pools , public fountains , and ornamental ponds, fire protection and public parks • Industrial purposes • For processing and cooling • Agricultural purpose • Irrigation • Power production from hydro power and steam power • Carrying away waste from all manners of establishment

  6. Sources of Water • Water source is any point in hydrological cycle which confirms to essential criteria • Quantity provided must be sufficient to meet present and future requirements • Quality of water must be acceptable

  7. sources • Rain • Surface water • Impounding reservoirs • Rivers and streams • Tanks ponds and lakes • Ground water • Shallow wells • Deep wells • Springs

  8. Polluted water

  9. Contaminated water • Water contain impurities of many kind • Natural • Nitrogen ,carbon dioxide , hydrogen sulphideetc • salts of calcium ,magnesium and sodium • clay ,silt, sand and mud • Man made • urbanization • industrialization • Sewage agents • industrial and trade waste • agricultural pollutants • physical pollutants (heat and radioactive substances)

  10. Water borne diseases • Water borne diseases are diseases caused due to consumption of contaminated water

  11. Biological • Diseases due to presence of aquatic intermediate host • Snail • Shistosomiasis • Cyclops • Guinea worm • Fish tape worm • CLASSIFICATION • Diseases caused by presence of infected agent • Viral • Viral hepatitis A and E • Poliomyelitis • Rota viral diarrhea • Bacterial • Enteric fever(typhoid and parathyroid fever) • Bacillary dysentery • E.coli diarrhea • Cholera • Protozoal • Amoebiasis • Giardiasis • Heleminthic • Ascariasis • Enterobiasis • Trituriasis • Hydated disease • Leptospiral • Weil’s disease

  12. chemical • Industrial and agricultural wastes • Detergent solvents , cyanides ,heavy metals ,minerals and organic acid ,nitrogenous substances, bleaching agents ,dyes ,pigments , sulphides, ammonia, toxic and biocidal organic compound of great variety • Dental health • Cyanosis in infants(nitrates – methaemoglobinaemia) • Cardiovascular diseases( hardness of water is beneficial) • Skin diseases • Vector borne diseases like malaria. Dengue.

  13. Prevention • Health education • Purification of water • Surveillance of water quality • Legislation

  14. METHODS OF PURIFYING WATER

  15. Purification at small scale Domestic level

  16. Purification at small scale(Domestic level) • Purification of water is of great importance in community medicine. • The household or domestic purification of water can be done by single or combined use of any of the following method. • Boiling • Chemical disinfection • Bleaching powder • Chlorine solution • High test hypochlorite • Chlorine tablets • Iodine • Potassium permanganate • Filtration • UV radiation • Multistage reverse osmosis(RO) purification of water

  17. Boiling • Boiling is a satisfactory method for purifying water for house hold purposes. • To be effective the water must be brought to a rolling boil for 5-10 minutes because it kills all bacteria, spores , cysts and ova • Water should be preferably stored in the same container in which water is boiled to avoid further contamination

  18. Boiling Main menu

  19. Advantages • It kills all bacteria ,spores, cysts and ova • It removes temporary hardness by driving of CO2 and precipitating CaCO3 • Dis advantages • Taste of water is altered but this is harmless • It offers no “residual protection’ against subsequent microbial contamination . • Can sometimes be difficult time consuming and cost inefficient because of the high volume of fuel used. • Will not remove mud from ‘murky ‘ water • Will not remove suspended or dissolved compounds

  20. Chemical disinfection • Chlorination • The principle of chlorination is to ensure a free residual chlorine of 0.5mg /L at the end of one hour of contact • Disinfection action of chlorine is due to formation of hypochloric acid • Most effective method water treatment in rural setup

  21. 1- bleaching powder • Bleaching powder or chlorinated lime is a white amorphous powder with a pungent smell of chlorine • Freshly made bleaching powder contains 33% available chlorine • It is an unstable compound and rapidly loses its chlorine content on exposure to air , light and moisture • But it retains its strength when mixed with excess of lime and is called stabilized bleach • Therefore it should be stored in cool , dark and dry place in a closed container and its chlorine content should be checked frequently.

  22. Chlorine solution • it is prepared from the bleaching powder by mixing 4kg of bleaching powder with 25% available chlorine is mixed with 20 liters of water to attain 5% solution of chlorine • They are also liable to lose chlorine content on exposure to light or on prolonged storage .therefore, they should be kept in a dark ,cool , and dry place in a closed container

  23. High test hypochlorite • High test hypochlorite (HTH) or perchloron is a calcium compound which contains 60-70% available chlorine • It is more stable than bleaching powder and deteriorates much less on storage . • Chlorine tablets • A chlorine tablets of 0.5g is sufficient quite good to disinfect 20 liters of water • But the tablets are costly

  24. Iodine • It is used for emergency disinfection where 2 drops of 2% ethanol solution of iodine suffice for 1 liter of clear water • A contact time of 20 -30 minutes is needed for effective disinfection • Advantages • Iodine does not react with ammonia or organic compounds hence remain in its active molecular form over a wide range of PH values and water conditions and persists longer • Disadvantages • High cost • Physiological activity of the iodine

  25. Potassium permanganate • A powerful oxidizing agent • Advantages • Active against cholera vibrios

  26. filtration • For small scale purification filters such as pasteurchamberland filter ,berkefeld filters and katadyne filters can be used. • The candle which is the essential part of the filter is made up of different materials in different filters like porcelain in chamber land type, kieselgurh or infusorial earth in berkefeld filters, etc • In katadyn filters ,the surface is coated with a silver catalyst which kills the micro organisms by its “oligo dynamic” action

  27. Filtering Main menu

  28. Advantages • Cheap • Removes bacteria Disadvantages • can not remove viruses • Only clean water should be used • Requires periodic cleaning by scrubbing with hard brush under running water and boiling at least once a week.

  29. UV radiations • Consists of direct exposure of film of water of about 1.5 cm thick to UV rays of 2,538 anstrom units (200, 300 mm) emitted by mercury vapor quartz lamp • Thinner the water film , rapid the absorption of rays • Water should be free from turbidity

  30. Advantages • Destroys both vegetative and spore form of bacilli • No residual effect • Not harmful • No taste or order • Dis advantages • High cost of operation • Regular maintenance • Effectiveness diminished by color turbidity and iron in water • No rapid test for assessment

  31. Reverse osmosis • Reverse osmosis is based on water reverse theory in nature • Advantages • Besides removing all pathogens ,restores or improves natural taste of water. • Dis advantages • Loss of naturally occurring minerals • Slow process requiring long time to purify • Wastage of water ( for every 1 liter of pure water,4 liter is wasted) • Costly (initial investment high but becomes economical in long run) • Regular maintenance

  32. Purification at large scale

  33. In industrial countries large scale water purification is done by rapid sand filters • The steps involved in the purification of water are • Coagulation • Rapid mixing • Flocculation • Sedimentation • Filtration • Chlorination • Storage

  34. Rapid and slow sand filters

  35. Thank you

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