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

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

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

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

6. Aquifiers

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

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

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

10. Taste and Odour Mainly due to organic substances,,Biological activity, industrial pollution 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 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. Water should be free from objectionable taste and odour.

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

12. Solids Total Solids Residue on evaporation at 103 o C TS = (W ds – W d )/V Where:W ds = weight of dish plus solids after evaporation W d = weight of dish alone V = volume of sample

13. Total Solids can be divided into two fractions: Suspended Solids Dissolved Solids Dissolved solids are the solids that can pass through a glass fiber filter with a 0.45 micro pore size Suspended solids are the solids that can not pass through a glass fiber filter with a 0.45 micron pore opening

14. Suspended solids SS = (F df – F d )/ V Where:F df = weight of the Filter plus dry filtered solids F d = weight of the clean, dry filter V = volume of sample

15. Volatile and Fixed Solids Volatile solids are the solids that are volatilized at 600 o C Fixed solids are the solids that remain after heating to 600 o C Generally the volatile solids are considered to be the organic fraction of the solids. Volatile Solids = Total Solids – Fixed Solids

16. Solids: significance TDS: used as a measure of inorganic salt content in drinking waters and natural waters TDS: used as a measure of inorganic salt content in drinking waters and natural waters TSS: used to assess clarifier performance TSS: used to assess clarifier performance VSS: used to estimate bacterial populations in wastewater treatment systems VSS: used to estimate bacterial populations in wastewater treatment systems

17. Solids Analysis

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

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

20. Battery acids <1.0Milk6.7 Carbonated Beverages 2 – 4 Rain water 6.5 Lemon juice 2.3Blood7.5 Orange juice 4.2Sea water water8.0 Vinegar3 Ammonia solution 11.3 Domestic sewage 6.5-8.5Ground water water7.5-8.5

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

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

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

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

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

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

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

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

29. ARSENIC Occur in ground water from arseniferous belt Occur in ground water from arseniferous belt Industrial waste, agricultural insecticide 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 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 Acceptable limit – 0.05 mg / l

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

31. Pesticides Cancer Cancer Birth defects Birth defects Blood disorder Blood disorder Nervous disorder Nervous disorder Genetic damage Genetic damage

32. Essential bacteriological Standards Characteristics Number / 100 ml Treated water in distribution system Feacal coliform zero Total coliform not more than 10 Total coliform should not be detectible in two consecutive samples

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

34. Common problems contd Visible effects Reasons water turns black,smell water turns black,smell Waste water Acidic taste Low pH Alkaline taste High pH Boiled Rice hard and yellow High Alkalinity White deposits on boiling Hardness

35. Common problems Visible effects Reason Iron taste, change in colour after exposure to atmosphere, change in colour of cloths,utensils Oily appea- rance on top of water body Iron Soap not lathering hardness Brownish black streaks on teeth `Fluride Growth of Algae Nitrate, phosphate Fish kills Low pH less DO Salty taste chloride

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

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

38. 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 CO 2 Calculate the theoretical oxygen demand of 1.67 x 10 -3 moles of glucose (C 6 H 12 O 6 ): C 6 H 12 O 6 + O 2  CO 2 + H 2 O general, unbalanced eqn C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6 H 2 O 1.67x 10 -3 moles glucose/L x 6 moles O 2 / mole glucose x 32 g O 2 /mole O 2 = 0.321 g O 2 /L = 321 mg O 2 /L

39. BOD Test Dark 20 o C Time Standard – 5 days Ultimate

40. 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) DD = dilution as a fraction D = volume of bottle/(volume of bottle – volume of dilution water) BOD = (8 – 4) 10 = 40 mg/L

41. 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

42. Example Calculate the BOD 5 of a sample under the following conditions. Seeded dilution water at 20 o C 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 20 o C 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 20 o C, DO sat = 9.07 mg/L BOD 5 = [(9.07 – 2) – (9.07 – 8)(290/300)] 30 = 174 mg/L

43. Chemical Oxygen Demand Same principle as BOD but different execution. Rather than biologically decompose/oxidize organic waste, we chemically decompose/oxidize organic waste.

44. COD: A chemical test The chemical oxygen demand (COD) of a waste is measured in terms of the amount of potassium dichromate (K 2 Cr 2 O 7 ) reduced by the sample during 2 hr of reflux in a medium of boiling, 50% H 2 SO 4 and in the presence of a Ag 2 SO 4 catalyst.

45. COD errors The most common COD errors are due to oxidation of inorganic species. Dichromate is a powerful oxidant – it will oxidize not only almost all organics but many metals and non-metal ions: 6 Fe 2+ + Cr 2 O 7 2- + 14 H + → Fe 3+ + 2 Cr 3+ + 7 H 2 O 6 Cl - + Cr 2 O 7 2- + 14 H + → 3 Cl 2 + 2 Cr 3+ + 7 H 2 O

46. COD errors As a result, contaminated water will tend to test higher than it should based strictly on the organic contamination.

47. COD vs. BOD They purport to measure the same thing – but they will never agree. Biggest error in BOD? BOD tends to err on the low side due to humus (“inedible” organic waste). Biggest error in COD? COD tends to err on the high side due to oxidation of inorganic species.

48. Using COD COD is again a relative measure: higher COD = dirtier water. COD can be used with BOD – they are not a replacement for each other. COD must be viewed in context of all other tests.

49. Comparing all of our “oxygens” Dissolved oxygen (  ) – amount of actual oxygen dissolved in a water sample. Higher number = purer water BOD 5 – Actual amount of dissolved oxygen metabolised over 5 days. Higher number = dirtier BOD – Extrapolated amount of theoretical oxygen that would be needed to completely metabolise organic waste. Higher number = dirtier COD – Actual amount of oxygen required to completely oxidize organic waste CHEMICALLY. Higher number = dirtier.