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WELCOME

WELCOME. PHYSICAL, CHEMICAL & BACTERIOLOGICAL CONTAMINATION OF WATER AND WATER QUALITY STANDARDS. Distribution of water on earth. Ocean and sea - 97% Snow and ice caps - 2% Rivers,lakes, Ground water - 1%. UNIVERSAL SOLVENT. QUALITY DEMERIT

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WELCOME

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  1. WELCOME

  2. PHYSICAL, CHEMICAL & BACTERIOLOGICAL CONTAMINATION OF WATER AND WATER QUALITY STANDARDS

  3. Distribution of water on earth • Ocean and sea - 97% • Snow and ice caps - 2% • Rivers,lakes, Ground water - 1%

  4. UNIVERSAL SOLVENT • QUALITY • DEMERIT • 45 LAC WELLS AND 50 LAC SEPTIC TANKS ( ?)

  5. contamination • Geological • Human activities . Organic waste Industrial waste

  6. Aquifiers

  7. Safe drinking water Free from pathogenic organisms Clear Not saline Free from offensive taste or smell Free from compounds that may have adverse effect on human health Free from chemicals that cause corrosion of water supply systems

  8. WATER QUALITY PARAMETERS • Physical parameters • Chemical • Bacteriological

  9. Colour • May be due to the Presence of organic matter,metals(iron, manganese) or highly coloured industrial waste • Aesthetically displeasing • Disirable that drinking water be colourless • Disirable limit, 5 Hazen unit • Permissible limit 25 Hazen Unit

  10. Taste and Odour • Mainly due to organic substances, ,Biological activity, industrial pollution • Taste buds in the oral cavity specially detect inorganic compounds of metals like magnesium, calcium, sodium, copper, iron and zinc • Water should be free from objectionable taste and odour.

  11. Turbidity • Caused by suspended matter • High level turbidity shield and protect bacteria from the action of disinfecting agents • Disirable limit-5NTU should be below 1 NTU when disinfection is practiced Permissible limit-10NTU

  12. pH • It is the measure of hydrogen ion concentration • Neutral water pH-7 • Acidic water has pH below 7 • Basic water has pH above 7 • Disirable limit 6.5-8.5 Beyond this limit the water will affect the mucous membrane and water supply system

  13. Acidic Industries Sugar - 5 – 6 Distillery 3 - 4 Electro- Plating unit 2.5-4 Pickle 2 - 3 Basic Paper 8 – 10 Textile 8.5-11 Fertiliser 6.5- 9 Oil Refine- ries 6.5-9.5 Substances that change pH of water

  14. HARDNESS • Capacity of water for reducing and destroying the lather of soap • It is total concentration of calcium and magnesium ions • Temporary hardness – Bicarbonates of Calcium and Magnesium • Permanent hardness – Sulphates, chlorides and nitrates of calcium and magnesium

  15. Hardness – contd… • 0 – 50 mg/l - soft • 50 – 150 mg/l - moderately hard • 150 – 300 mg/l - hard • 300 above - very hard • Surface water is softer than ground water • Causes encrustations in water supply structures

  16. ALKALINITY • Capacity to nutralise acid • Presence of carbonates, bi-carbonates and hydroxide compounds of Ca, Mg, Na and K • Alkalinity = hardness, Ca and Mg salts • Alkalinity > hardness - presence of basic salts, Na, K along with Ca and Mg • Alkalinity < hardness – neutral salts of Ca & Mg present

  17. IRON • One of the earth’s most plentiful resource • High iron causes brown or yellow staining of laundry, household fixtures • Metalic taste, offensive odour, poor tasting coffee • Cause iron bacteria • Acceptable limit – 0.3 mg / l

  18. CHLORIDE • Causes • Dissolution of salt deposit • Discharge of effluents • Intrusion of sea water • Not harmful to human beings • Regarding irrigation – most troublesome anion • Acceptable limit - 250 mg/l

  19. NITRATE • Increasing level of nitrate is due to • Agricultural fertilizers, manure,animal dung, nitrogenous material ,sewage pollution • (blue baby diseases to infants) • Maximum permissible limit 45 mg / l

  20. FLOURIDE • Occurs naturally • Long term consumption above permissible level can cause – • dental flurosis (molting of teeth) • Skeletal flurosis • Acceptable limit – 1 mg / l • Maximum permissible limit – 1.5 mg / l • Remedy – 1) Deflouridation 2) Mixing Fluride free water 3) Intake of vitamin C,D, calcium,antioxidants

  21. FLOURIDE CAUSES Three types of Fluorosis 1. Dental Fluorosis 2. Skeletal Fluorosis 3. Non-skeletal Fluorosis

  22. ARSENIC • Occur in ground water from arseniferous belt • Industrial waste, agricultural insecticide • High arsenic causes 1) various type of dermatological lesions, muscular weakness, paralysis of lower limbs, can also cause skin and lung cancer • Acceptable limit – 0.05 mg / l

  23. Heavy Metals • Present as mineral in soil and rocks of earth • Human activities Battery – Lead & Nickel Textile - Copper Photography – Silver Steel production – Iron

  24. Pesticides • Cancer • Birth defects • Blood disorder • Nervous disorder • Genetic damage

  25. Essential bacteriological Standards

  26. RESIDUAL CHLORINE Chlorine added to water forms hypochlorite ions and hypochlorite acids Chlorine demand – Quantity required for killing micro organisms and reacting with ammonia, organic compounds etc. Free residual chlorine – To take care of post contamination Desirable – 0.2 mg / liter

  27. Common problems contd

  28. Common problems

  29. Measures of Water Quality Some of the Most basic and Important Measures Dissolved Oxygen Biochemical Oxygen Demand Solids Nitrogen Bacteriological

  30. Dissolved Oxygen (DO) Typically Measured by DO probe and Meter Electrochemical Half Cell Reaction

  31. Biochemical Oxygen Demand (BOD) Amount of oxygen used by microorganisms to decompose organic matter in a water Theoretical BOD can be determined by balancing a chemical equation in which all organic matter is converted to CO2 Calculate the theoretical oxygen demand of 1.67 x 10-3 moles of glucose (C6H12O6): C6H12O6 + O2 CO2 + H2O general, unbalanced eqn C6H12O6 + 6 O2 6 CO2 + 6 H2O 1.67x 10-3moles glucose/L x 6 moles O2/ mole glucose x 32 g O2/mole O2 = 0.321 g O2/L = 321 mg O2/L

  32. BOD Test Dark 20oC Time Standard – 5 days Ultimate

  33. BOD = I - F I = Initial DO F = Final DO If all the DO is used up the test is invalid, as in B above To get a valid test dilute the sample, as in C above. In this case the sample was diluted by 1:10. The BOD can then be calculated by: BOD = (I – F) D D = dilution as a fraction D = volume of bottle/(volume of bottle – volume of dilution water) BOD = (8 – 4) 10 = 40 mg/L

  34. For the BOD test to work microorganisms have to be present. Sometimes they are not naturally present in a sample so we have to add them. This is called “seeding” a sample If seed is added you may also be adding some BOD. We have to account for this in the BOD calculation: BOD = [(I – F) – (I’ – F’)(X/Y)]D Where: I’ = initial DO a bottle with only dilution water and seed F’ = final DO of bottle with only dilution water and seed X = amount of seeded dilution water in sample bottle, ml Y = amount of seeded dilution water in bottle with only seeded dilution water

  35. Example Calculate the BOD5 of a sample under the following conditions. Seeded dilution water at 20oC was saturated with DO initially. After 5 days a BOD bottle with only seeded dilution water had a DO of 8 mg/L. The sample was diluted 1:30 with seeded dilution water. The sample was saturated with DO at 20oC initially. After five days the DO of the sample was 2 mg/L. Since a BOD bottle is 300 ml a 1:30 dilution would have 10 ml sample and 290 ml seeded dilution water. From the table, at 20oC, DOsat = 9.07 mg/L BOD5 = [(9.07 – 2) – (9.07 – 8)(290/300)] 30 = 174 mg/L

  36. Thank you

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