Water Basics
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The document details the fundamental properties and significance of water, including its chemical composition, effects on the human body, and various measurable properties like pH, turbidity, and UV transmittance. It discusses how contaminants from both natural and man-made sources can impact water quality and poses potential health risks. Additionally, the document outlines the environmental factors that influence water's characteristics and the importance of pre-treatment for effective water purification.
Water Basics
- 1. Water Basics Importance of water: The Human Body
- 2. Basic Water Chemistry: Measurable Properties
- 3. Fundamentals of Water Technology: Hydrologic Cycle
- 4. Nature of Water: Environmental Factors
- 5. Contamination: Origin & Potential ProblemsWater BasicsThe Importance of Water:Brain 75 % WaterThe human body is made up of approximately 70% water; therefore water is vital to all systems
- 6. ‘Clean’ water is essential for the human body
- 7. Contaminants present in water can bio-accumulate in the body causing health issues – i.e. carcinogens like THM’s can bio-accumulate possibly causing cancer in the futureCirculatory System 80% WaterCirculatory System 80% WaterLungs 86% WaterMuscles 75% Water
- 8. Water BasicsWater ChemistryWater Molecule: 2 Hydrogen atoms1 Oxygen atom Water is an extremely stable compound composed of Hydrogen & Oxygen atoms
- 9. It is referred to as the universal solvent as it dissolves more substances than any other liquid
- 10. Water is unique as it is only natural substance that is found in three states – liquid, solid, gas
- 11. Water is very rarely in pure ‘distilled’ form
- 12. Water will always contain salts, nutrients & particulates depending on local conditionsWater BasicsMeasurable Properties of Water: pHpH: refers to water being acidic, basic or neutral; pH is affected by chemicals therefore is a good indication that water may be changing chemically pH stands for the potential of hydrogen
- 13. The neutral point of 7 indicates the presence of equal concentrations of free hydrogen & hydroxide ions
- 14. Each decrease in pH by one pH unit means a tenfold increase in concentration of hydrogen ions – therefore more acidicWater BasicsMeasurable Properties of Water: Hardness(1)H20 + CO2H2CO3(water) (carbon dioxide) (carbonic acid)PRECIPGAS IN ATMWEAK ACID(2) CaCO3 + H2CO3 Ca(HCO3)2 or Mg(HCO3)2(calcium carbonate) (carbonic acid) (calcium bicarbonate)HARDNESS/LIMESTONE WEAK ACID SOLUBLE HARDNESS As moisture falls through atmosphere, it absorbs amounts of CO2
- 15. When CO2 dissolves in water, some of it forms a weak acid called carbonic acid
- 16. This carbonic acid then comes into contact with limestone (carbonate) on the earth’s surface, dissolving it thereby producing calcium & magnesium bicarbonates
- 17. Bicarbonates are known as ‘Temporary Hardness’
- 18. These bicarbonates are highly soluble; when heated bicarbonates will release CO2 & revert back to carbonates or an ‘insoluble state’ = HARDNESSWater BasicsMeasurable Properties of Water: Turbidity Turbidity is amount of small particles of solid matter suspended in water
- 19. Turbidity is measured with a Turbidimeter
- 20. Turbidimeterreads sample by amount of scattering & absorption of light rays caused by particles present in sample
- 21. Turbidity blocks light rays and can make a water sample appear cloudy
- 22. Turbidity CANNOT be directly equated to suspended solids (TSS) as white particles will reflect more light than dark colored particles & many small particles will reflect more light than an equivalent large particle
- 23. Turbidity CANNOT be directly equated to UVT levelsWater BasicsMeasurable Properties of Water: TurbidityTurbidity is measured with a turbidimeter
- 24. Turbidimeter is calibrated using vials of solution which contain different NTU levels
- 25. Turbidity can make water either cloudy or opaque depending on what makes up turbidity
- 26. Turbidity is measured in NTU’s(Nephelometric turbidity units)The higher the NTU value, the higher the intensity of scattered lightLess UV light getting through the waterWater BasicsMeasurable Properties of Water: UV Transmittance (UVT) UVT is a measure of how well water is able to transmit UV light
- 27. If the UV light cannot penetrate the water then it cannot penetrate the microorganisms present in the water
- 28. As the UVT drops UV dose also drops dramatically
- 29. UVT (%) is the most important water quality property to be considered when looking at UV as a piece of water treatment equipment
- 30. Keep in mind that low UVT levels are not always detectable with the naked eye
- 31. Tannins are visual in water but there are many other organics that can drop the UVT with no color at allHigh UVT= High DoseLow UVT= Low Dose
- 32. Water BasicsMeasurable Properties of Water: Iron (Fe) One of earth’s most plentiful resources (5% of earth’s crust)
- 33. Rainfall seeping through soil dissolves iron in crust & carries it into almost every kind of water supply, mostly well water
- 34. Iron is seldom found at concentrations greater than 10 ppm
- 35. Iron is not hazardous to human health, it is considered a secondary aesthetic contaminant
- 36. At levels of 0.3 ppm staining of household fixtures can occur
- 37. Iron can be present in water in either a clear soluble (ferrous iron or clear water iron) or insoluble (ferric iron ) state; is often associated with iron bacteria problems
- 38. When considering iron removal (i.e. with a softener) ensure that the outdoor taps are being treated….what could happen you ask? Iron staining in toilet
- 39. Water BasicsMeasurable Properties of Water: Manganese (Mn) This element is usually found in groundwater
- 40. Usually present in combination with iron (but in lower concentrations)
- 41. At levels of 0.05 ppmMn can cause staining of a black-yellow color
- 42. Both Fe & Mn can be present in well water & water can appear clear when first drawn
- 43. Upon exposure to air both soluble Fe & Mn will quickly become oxidized changing to their insoluble state (a precipitate)Water BasicsMeasurable Properties of Water: Tannins Tannins are water soluble, organic phenolic compounds formed in the decomposition of vegetation
- 44. Tannins occur in water in almost any location where large quantities of vegetation have decayed
- 45. Cannot simply be filtered out of water as tannins consist of microscopic, unsettlable, colloidal particles that carry a negative charge
- 46. Due to the materials that have decayed, tannins create a yellowish color in water
- 47. This may not be visible in a glass of water, however a tubful of water will appear slightly yellow (or Styrofoam cup)
- 48. Above a pH of 6 tannins must be removed by anion exchange; below 5 they may be removed by activated carbon depending on tannin concentrationClean & tannin watercomparisonTubful of tannin water
- 49. Water BasicsWhat can these parameters do to a UV system? Hardness, iron, manganese & tannins can all inhibit UV light from penetrating microorganisms in water
- 50. This is done either by absorption or scaling
- 51. If the sleeve is coated then UV light is trapped & cannot reach the water
- 52. A non-monitored system needs to have water that is pre-treated or is of a known qualityWater BasicsMeasurable Properties of Water: Hydrogen Sulphide (H2S) H2S is a corrosive, flammable & toxic gas often found dissolved in well water, accompanied by iron & low pH
- 53. Develops from decaying organic matter or sulfate-reducing bacteria (SRB)
- 54. SRB produces enzymes which accelerates reduction of sulfur compounds thereby producing H2S
- 55. Produces rotten egg smell, can corrode piping & turn water black
- 56. In some cases H2S may only be present in household hot water
- 57. This condition is caused by a biochemical reaction between sulfates in water, sulfate reducing bacteria or organic matter Structure model of HydrogenSulfide
- 58. Water BasicsFundamentals of Water Technology:
- 59. Water BasicsThe Nature of Water – Environmental FactorsWater is a product of the environment, absorbing & dissolving a part of everything it touches in both air & water
- 60. Water BasicsThe Nature of Water – Environmental FactorsAIR:As water falls to earth the rain serves to cleanse air Rain will absorb solid matter, gases, odors & other impurities that pollute air Carbon dioxide gases in atmosphere can penetrate precipitation as it falls, causing rainfall to become slightly acidic (carbonic acid) Rainwater can also encounter sulfuric acid & some types of bacteriaSURFACE: Surface properties have a great impact on water reaching earth As water percolates into ground it loses some of its impurities it absorbed from air BUT while the soil filters out impurities it also allows water to dissolve large amounts of earth’s minerals etc.Vegetated Areas: O2 is consumed & CO2 is produced through decay of vegetationLimestone Areas: H20 containing H2CO3 reacts with stone becoming hard; Ca, Mg bicarbonates are formedGranite/Sandy Areas: H20 holds H2CO3 but does not become hard due to absence of limestone
- 61. Water BasicsContamination: Contamination in drinking water can exist in many different forms:
- 63. Colloidal Matter
- 64. Dissolved Solids
- 66. Microorganisms (protozoan cysts, viruses, pyrogens)
- 69. These exist either naturally or are man made.Water BasicsContaminants & their origin:MAN-MADENaturallyOccurringIndustrialAgriculturalDirtRustSedimentRootsLeavesAlgaeMold,Iron (Fe)Calcium (Ca)Magnesium (Mg)Manganese (Mn)Hydrogen sulfideMicroorganismsCysts (Cryptosporidium, Giardia)DetergentSolventRadio-active wasteAcidsHydrocarbonCarbon monoxideLead based contaminants ChlorineChloraminesTHM’setc...FertilizerHerbicidePesticideNitrateFungicide
- 70. Water BasicsPotential Problems with Contaminants:
- 71. For More InformationVisit the Water University at