Water Quality Control & Treatment


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Water Quality Control & Treatment

  1. 1. Water Quality Control and Treatment By Dr. Khamis AL-Mahallawi
  2. 2. Water • Water is  a chemical substance with  the chemical formula  H2O. • Its  molecule  contains  one oxygen and  two hydrogen atoms  connected by covalent bonds.  • Water  is  a liquid at ambient conditions,  but  it  often  co-exists  on  Earth  with  its solid state,  ice,  and gaseous state  ( water vapor or steam).  Water  also  exists  in  a liquid crystal  state near hydrophilic surfaces
  3. 3.  Chemical and physical properties of water • Water is a liquid at standard temperature and pressure. It is tasteless  and odorless.  • water is a polar molecule   • Water is a good solvent (universal solvent).  • Substances that dissolve in water are known as hydrophilic (waterloving) substances, while those that do not mix well with water are  known as hydrophobic (water-fearing) substances. • All the major components in cells (proteins, DNA and  polysaccharides) are dissolved in water. • Pure water has a low electrical conductivity,  • The boiling point of water is dependent on the barometric pressure.  (on the top of  Mt. Everest water boils at 68 °C, compared to 100 °C  at sea level. 
  4. 4. Chemical and physical properties of water • water is moderate Earth's climate by buffering large  fluctuations in temperature. • Water  is miscible with  many  liquids,  such  as ethanol,  forming a single homogeneous liquid. • water and most oils are immiscible usually forming layers .  • As a gas, water vapor is completely miscible with air. • Water can be split by electrolysis into hydrogen and oxygen. • The energy required to split water into hydrogen and oxygen  by electrolysis or any other means is greater than the energy  that  can  be  collected  when  the  hydrogen  and  oxygen  recombine. • Elements which are electroposistive than hydrogen   such as  lithium, sodium, calcium,  and  potassium  displace  hydrogen  from water, forming hydroxides. 
  5. 5. Sustainable development development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
  6. 6. Sustainable development / water In relation to water the concepts set out above can be interpreted as follows. • Water is a scarce resource which should be viewed as both a social and an economic resource. • Water should be managed by those who most use it, and all those who have an interest in its allocation should be involved in the decision making. • Water should be managed within a comprehensive framework, taking into account its impact on all aspects of social and economic development.
  7. 7. Units of Concentration • Solution: a mixture consisting of a solute and a solvent • Solute: component of a solution present in the lesser amount • Solvent: component of a solution present in the greater amount • Concentration: amount of a solute present in a solution per amount of solvent
  8. 8.   )%(Concentration / Percent Composition by Mass Concentration may be expressed several different ways • Percent Composition by Mass )%(  Where the mass of the solution is equal to the mass of the solute plus  the mass of the solvent.  Example: Determine the percent composition by mass of a 100 g salt  solution which contains 20 g of NaCl salt. Solution: 20 g NaCl / 100 g solution x 100 = 20% NaCl solution.
  9. 9. (Concentration / Volume Percent )% v/v • Volume  Percent  (%  v/v):  most  often  is  used  when  preparing  solutions of liquids. Volume percent is defined as: • Note  that  volume  percent  is  relative  to  volume  of  solution,  not  volume of solvent.  • For example, wine is about 12% v/v ethanol. This means there are  12 ml ethanol for every 100 ml of wine. • It is important to realize liquid and gas volumes are not necessarily  additive. If you mix 12 ml of ethanol and 100 ml of wine, you will  get less than 112 ml of solution.
  10. 10. Concentration / Mole Fraction • Mole Fraction )X(: This is the number of moles of a compound divided by the total  number of moles of all chemical species in the solution.  Example: What are the mole fractions of the components of the solution formed when 92 g  glycerol is mixed with 90 g water? (molecular weight water = 18; molecular weight  of glycerol = 92) Solution: 90 g water = 90 g x 1 mol / 18 g = 5 mol water 92 g glycerol = 92 g x 1 mol / 92 g = 1 mol glycerol total mol = 5 + 1 = 6 mol xwater = 5 mol / 6 mol = 0.833 x glycerol = 1 mol / 6 mol = 0.167 It's a good idea to check your math by making sure the mole fractions add up to 1: xwater + xglycerol = .833 + 0.167 = 1.000
  11. 11. Concentration / Molarity • Molarity )M(: is probably the most commonly used unit of concentration. It is  the number of moles of solute per liter of solution (not necessarily the same as  the volume of solvent).  Example: What is the molarity of a solution made when water is added to 11 g  CaCl2 to make 100 mL of solution? Solution: 11 g CaCl2 / (110 g CaCl2 / mol CaCl2) = 0.10 mol CaCl2 100 mL x 1 L / 1000 mL = 0.10 L molarity = 0.10 mol / 0.10 L molarity = 1.0 M
  12. 12. Concentration / Molarity How many millilieters of 5.5 M NaOH are needed to prepare 300 mL of 1.2 M NaOH? Solution: 5.5 M x V1 = 1.2 M x 0.3 L V1 = 1.2 M x 0.3 L / 5.5 M V1 = 0.065 L V1 = 65 mL • So, to prepare the 1.2 M NaOH solution, you pour 65 mL of 5.5 M NaOH into your container and add water to get 300 mL final volume
  13. 13. Concentration / Normality Normality (N): is equal to the gram equivalent weight of a solute per liter of solution. A gram equivalent weight or equivalent is a measure of the reactive capacity of a given molecule. Normality is the only concentration unit that is reaction dependent. Example: 1 M sulfuric acid (H2SO4) is 2 N for acid-base reactions because each mole of sulfuric acid provides 2 moles of H+ ions. On the other hand, 1 M sulfuric acid is 1 N for sulfate precipitation, since 1 mole of sulfuric acid provides 1 mole of sulfate ions.
  14. 14. Concentration / Mass per unit volume ()mg/mL • • • • • Mass per unit volume it can be given in mg/m3 - mg/l (mg/mL) (mg/cm3) Note that 1 mL = 1 cm3 and that cm3 is sometimes denoted as a "cc". In air pollution measurements, the mass of pollutant is expressed as micrograms of pollutant per cubic meter of air (1 millionth of a grams per cubic meter of air), μg/m3 - mass of species per unit volume of air. In water, mass/volume concentration of mg/l and μg/m3 are common. In most aqueous systems, ppm is equivalent to mg/l.
  15. 15. Concentration units in water chemistry The concentration of a chemical in a water sample is commonly measured and reported in ; • mass concentration, often expressed in units of g/L - mg/L • parts per million on a weight : weight basis (1 mg/L = 1 ppm) • equivalent weight ; Example of calculation: Na+ atomic weight 23 1 meq/l = 23/1 mg/l Ca2+atomic weight 40 1 meq/l = 40/2 mg/l
  16. 16. Ion Balance • For  neutrality  and  to  calculate  the  balance  error  of  water  sample  test, the total amount of cations expressed in meq/l must be equal  to the total amount of anions expressed in meq/l. 
  17. 17. Calculation of Ion Balance
  18. 18. Possible reasons of errors
  19. 19. Possible reasons of errors
  20. 20. Objective in water quality control Water quality is the physical, chemical and biological characteristics of water. A major objective in water quality control work is to reduce the incidence of waterrelated diseases  i.e water free from • visible suspended matter • excessive color, taste and odor • objectionable dissolved matter • aggressive constituents • bacteria indicative of faecal pollution. The concept of integrated pollution control (IPC) is highly relevant to the effective  conservation and management of the global environment 
  21. 21. GENERAL CLASSIFICATION OF POLLUTANTS • Pollution:  is  defined  as  the  deterioration  of  the  existing state. • Pollution is  the  introduction  of  contaminants  into  a  natural  environment  that  causes  instability,  disorder,  harm  or  discomfort  to  the ecosystem i.e.  physical  systems or living organisms. • Pollution  is  often  classed  as point source or  nonpoint source pollution.  
  22. 22. Sources of water pollution
  23. 23. SOURCES OF WATER POLLUTION When  pollution  control  is  considered,  these  questions should be asked and answered. 1. Can the pollution source be eliminated? 2. Can the pollution source be minimized? 3. Can the pollutants be reused? 4. Can the pollutant be treated?
  25. 25. INDUSTRIAL SOURCES OF WATER POLLUTION 1. Non-Contact Water • Boiler feed water • Cooling water • Heating water • Cooling condensate 2. Contact Water • Water used to transport products, materials or chemicals • Washing and rinsing water (product, equipment, floors) • Solubilizing water • Diluting water • Direct contact cooling or heating water • Sewage • Shower and sink water
  26. 26. MUNICIPAL SOURCES OF WATER POLLUTION The non-industrial municipal sources of water are typically as follows: • Dwellings • Commercial establishments • Institutions (schools, hospitals, prisons, etc) • Governmental operations It is assumed that a non-industrial municipal wastewater source will contain no pollutants except for the following: • Feces • Urine • Paper • Food waste • Laundry wastewater • Sink, shower, and bath water
  27. 27. AGRICULTURAL SOURCES OF WATER POLLUTION • Agricultural water pollutants are transported to an aboveground or  underground receiving stream by periodic stormwater • Agricultural wastewater can be of animal or vegetable origin or be from a  nutrient, fertilizer, pesticide or herbicide source.  • Animal or vegetable sources will be limited to biodegradable feces, urine or  vegetable constituents. • Nutrients or fertilizers will be typically some formulation of carbon,  phosphorous, nitrogen and/or trace metals. • Pesticides and herbicides will consist of formulated organic chemicals, many  with complex molecular structures, designed to be very persistent in the  environment. Pesticides such as Chlorodane and Heptachlor, which consist of a  multitude of different organic chemicals, can still exist in the soil around  World War II barracks.
  28. 28. NATURAL SOURCES OF WATER POLLUTION • Areas  unaffected  by  human  activity  can  still  pollute  receiving steams due to stormwater runoff, which can  be classified into animal, vegetable and soil sources. •  Again, animal and vegetable water pollution sources  should be readily biodegradable.  • Soil sources will consist of any organic and inorganic  material in the soil.
  29. 29. STORMWATER SOURCES OF WATER POLLUTION • Stormwater  has  been  mentioned  above  under  agricultural  and  natural  sources  of  water  pollution, but will also transport industrial and  municipal  water  pollutants  to  a  receiving  stream or underground water supply.
  30. 30. Industrial Stormwater Sources • Any solid or liquid material or chemical stored, leaked or spilled on the ground from an industrial operation can be transported by stormwater to a recovery stream and become a pollutant. These sources can be from any or all of the following: • Outside process areas • Inside process areas which discharge to the outside • Roof drains • Parking lots • Roadways • Loading/unloading areas • Storage areas • Wastewater treatment areas • Soil runoff • Spills • Leaks • Tank farms
  31. 31. Municipal Stormwater Sources Any material or chemical deposited on the ground in a  municipality can likewise be transported to a receiving  stream as a pollutant.  These include: • Petroleum product spills and leaks • Garbage and trash • Soil runoff • Surfacing underground sewage disposal systems • Spills and leaks from material or chemical transport
  32. 32. LANDFILL WATER POLLUTION SOURCES • Public,  private,  and  industrial  landfills  can  be  a  source  of  stormwater  pollution because of runoff from the surface and underground leachate.  • When  stormwater  leaches  through  the  surface  cap  and  downward  through  the  landfill,  the  horizontally  or  vertically  migrating  discharge  from below the landfill is known as leachate and can pollute surface or  underground water. • Because of the bacteria present in the dirt and in landfill material, there  will  always  be  aerobic  and  anaerobic  biological  activity  occurring  in  a  landfill. 
  34. 34. PHYSICAL POLLUTANTS physical pollutants are categorized as follows: 1. Solids content 2. Solids type 3. Color 4. Odor 5. Taste 6. Conductivity 7. Temperature
  35. 35. PHYSICAL POLLUTANTS/ Solids Content 1. Solids Content • For regulatory and treatment purposes, total solids (TS) can first be classified as suspended or dissolved. • Total Solids: is the material residue left in a vessel after evaporation of a sample and its subsequent drying in an oven at 103 to 105°C for one hour • Total Suspended Solids (TSS) : is that portion of the Total Solids that are retained on a no-ash glass fiber filter disc of approximately 0.45 mm pore size. • Relationship Between TS, TSS and TDS. These three solids tests can be related with : TS = TSS +TDS
  36. 36. PHYSICAL POLLUTANTS / Solid Type The most basic solids differentiation is between settleable and floatable solids • Settleable Solids. A liter of wastewater is settled in an Imhoff cone for one hour and the milliliters of solids accumulating in the bottom is reported as settleable solids (S/S) in ml/l • Flotable Solids. The quickest and simplest test for floatable solids is to test TSS as explained above in a well mixed sample of the wastewater and then let the wastewater float quiescently for one hour. Then take a sample of the wastewater with a pipette from under the float and above any sediment. Run a TSS test on the second pipette sample and report as non-flotable, suspended solids (NFSS). The relation with TSS will be as follows: TSS = FSS + NFSS where FSS = Flotable Suspended Solids.
  37. 37. Total suspended solids filtering apparatus Settleable solids apparatus
  38. 38. PHYSICAL POLLUTANTS / Solid Type • Total Volatile Solids. The total volatile solids (TVS) test is used to determine whether a solid is organic, as approximated by being volatile, or inorganic (non-volatile). • To determine total volatile solids (TVS), the residue from the TS test described above is ignited in a weighed dish in a furnace at 550°C ± 50°C for 15 to 20 minutes and then weighed. The loss of weight is reported as TVS. The remaining weight is total non-volatile solids (TNVS). • The relationship between Total Solids and Volatile Solids is TS = TVS +TNVS • The total volatile solids test indicates the amount of the total solids which can potentially be destroyed chemically or biologically, volatilized through stripping, or adsorbed. • The non-volatile solids are typically inorganic and cannot be destroyed. These solids must be converted or removed by some physical or chemical method
  39. 39. PHYSICAL POLLUTANTS / Solid Type • Total Volatile Suspended Solids. The suspended solids collected on the no-ash filter in the TSS test described above can be ignited in a furnace at 550°C ± 50°C for 15 to 20 minutes to determine the total volatile suspended solids (TVSS). • The TVSS will be the loss of weight and the total nonvolatile suspended solids (TNVSS) will equal the remaining weight. • The relationship between Total Suspended Solids and Volatile Suspended Solids can be expressed as: TSS = TVSS +TNVSS
  40. 40. PHYSICAL POLLUTANTS / Solid Type • Total Volatile Dissolved Solids. If the dried filtrate from the TDS test is ignited in a furnace at 550°C + 50°C for 15 to 20 minutes, the residue can be reported as total non-volatile dissolved solids (TNVDS) and the loss of weight as total volatile dissolved solids (TVDS). TDS = TVDS + TNVDS
  41. 41. PHYSICAL POLLUTANTS / Turbidity • Turbidity in water can be caused by suspended matter such as silt, clay, organic matter, organic compounds, or dissolved inorganics. • Turbidity is determined by the optical property that causes light to be scattered, adsorbed or reflected rather than transmitted in a straight line through or into a liquid. • In the nephelometric method, the intensity of scattered light in a sample is compared with the intensity of light scattered by a standard reference solution under the same conditions. • The higher the intensity of scattered light, the higher the turbidity.
  42. 42. PHYSICAL POLLUTANTS/ Color • Color. water is “colored” if it is not completely clear. Color can be suspended color (apparent color) or dissolved color (true color) • Suspended particles can be removed by settling or filtration, and can be considered as suspended solids regardless of whether they are colored. • Dissolved color is of more concern and may be caused by vegetable or mineral dyes, other inorganic industrial wastes, or by organic material from stormwater runoff. • Dissolved color should be considered as inorganic or organic chemical water quality • Color is quantitatively determined by visual comparison with a known concentration of colored solutions or by spectrophotometric methods
  43. 43. PHYSICAL POLLUTANTS / Odor • Odor is rare as a permit pollutant, but may be prohibited in a pretreatment system. • The accepted odor test is the Threshold Odor Test in which a sample is diluted with pure water until the least perceptible odor is noticed. • The Minimum Detectable Threshold Odor Concentration (MDTOC) is reported as units or dilutions required to reduce an odor to its detectable limit. • If several people independently perform the Threshold Odor Test, the averaged Threshold Odor Number (TON) can be relatively accurate • the MDTOC equals the initial sample volume divided by the barely ((‫بالكاد‬ detectable sample volume: MDTOC = 100 ml / 25 ml = 4
  44. 44. PHYSICAL POLLUTANTS / Taste - Temperature • Taste. There are only four true tastes that can be recognized by tongue and palate sensory nerves: Bitter – Salty – Sour - Sweet There are three methods of determination: • The Flavor Threshold Test is similar to the odor test and is the greatest dilution of a sample using pure water which yields a perceptible taste. • The Flavor Rating Assessment is a scale for rating a drinking water as acceptable or not. • The Flavor Profile Analysis is a comparison between a wastewater taste and that of a documented sensory quality judged acceptable by trained testers. • Temperature. The temperature of a water is a physical water quality parameter since temperature can have a negative effect on aquatic life, especially the propagation of fish. Various types of fish require certain temperatures for existence and a lower temperature for propagation.
  45. 45. Electrical conductivity • Electrical conductivity (EC) is a measure of the ability of water to conduct an electric current The conductivity of a solution depends on: • Concentration of the ions (higher concentration, higher EC) • Temperature of the solution (high temperature, higher EC) • Specific nature of the ions (higher specific ability and higher valence, higher EC) • Knowing the appropriate value of K for a particular water, the measurement of conductivity provides a rapid indication of TDS content. • the electrical conductivity is expressed in Siemens per meter or milli Siemens per meter at 25ºC (mS.m-1).
  46. 46. Radioactivity • • Radioactivity. Measurements of gross beta and gama activity are routine quality checks. Radioactive substances are those that are unstable in nature. • Radioactive substances in ground water, such as radium, uranium and thorium, occur naturally • Naturally occurring radon (an alfa emitter) can be a possible long-term health hazard with some groundwater. • The acidity of the water, which may be increased by the presence of elevated levels of nitrates associated with agricultural land use, is believed to increase the amount of radium that dissolves into groundwater from contact with sands and soils. • Unit of concentration is picocurie per liter
  47. 47. three primary types of radiation: • Alpha - these are fast moving helium atoms. • Beta - these are fast moving electrons. Since electrons are might lighter than helium atoms, they are able to penetrate further, through several feet of air, or several millimeters of plastic or less of very light metals. • Gamma - these are photons, just like light, except of much higher energy, typically from several keV to several MeV. Radioactivity
  48. 48. Radioactivity How can beta particles affect people's health? • Beta radiation can cause both acute and chronic health effects. Acute exposures are uncommon. Contact with a strong beta source from an abandoned industrial instrument is the type of circumstance in which acute exposure could occur. Chronic effects are much more common. • Chronic effects result from fairly low-level exposures over a along period of time. They develop relatively slowly (5 to 30 years for example). The main chronic health effect from radiation is cancer. When taken internally beta emitters can cause tissue damage and increase the risk of cancer. The risk of cancer increases with increasing dose. • Some beta-emitters, such as carbon-14, distribute widely throughout the body. Others accumulate in specific organs and cause chronic exposures: • Iodine-131 concentrates heavily in the thyroid gland. It increases the risk of thyroid cancer and other disorders. • Strontium-90 accumulates in bone and teeth.
  49. 49. Typical Domestic Wastewater Compositions
  50. 50. CHEMICAL POLLUTANTS • Chemical pollutants can be organic or inorganic. • There are thousands of organic pollutants consisting of various combinations of carbon, hydrogen, and perhaps oxygen and/or many other inorganic or organic molecules. • In general, organic pollutants are more biodegradable with fewer carbon and/or other molecules attached • Inorganic chemical pollutants can be categorized into pure chemical pollutants and chemical indicators,
  51. 51. Naturally occurring chemicals • WHO has established guideline values for 9 compounds that can occur naturally in water. • Arsenic, As • Arsenic in drinking water is a global threat to health, potentially affecting about 140 million people in at least 70 countries worldwide • Arsenic can occur in drinking water either as the reduced species AsIII (arsenite) or the oxidized form, AsV (arsenate). • Arsenic occurs naturally in soils/rocks, with concentrations of about 2-10 mg/kg. • Arsenic causes skin lesions, but other effects can include weakness, diarrhoea, vascular disease and diabetes mellitus. The main health concerns are cancers of the skin or internal organs
  52. 52. Naturally occurring chemicals • • • • • • • • Barium, Ba. GV 0.7 mg/L (chronic exposure can cause hypertension in humans, leading to the GV of 0.7 mg/L. Short-term exposure to high levels of barium can cause gastrointestinal disturbances and muscular weakness ) Chromium, Cr. GV 0.05 mg/L (can cause lung cancer in humans) Boron, B. GV 0.5 mg/L (ingestion can cause lower foetal weight and testicular damage ) Fluorine, F. GV 1.5 mg/L (dental fluorosis -skeletal fluorosis involving stiffness and pain in joints) Manganese, Mn. GV 0.4 mg/L (strong unpleasant metallic taste - give rise to the deposition of black deposits in pipes) Molybdenum GV 0.07 mg/L (diarrhea, greying of hair and lowered growth rate) Selenium, Se. GV 0.01 mg/L (liver and kidney damage and hair and fingernail loss) Uranium U GV 0.015 mg/L (kidney damage)
  53. 53. Chemicals from industrial sources and human dwellings • Cadmium, Cd. GV 0.003 mg/L: Cadmium is used in metal plating, plastics, pigments and batteries (is cumulative in the kidney and liver organs and can cause death) • Cyanide GV 0.07 mg/L : used in metal finishing and the production of plastics such as nylon. (Cyanide is acutely toxic, primarily affecting the thyroid and the nervous system) • Mercury Hg GV 0.006 mg/L: Mercury is used in the electrolytic production of chlorine; in electrical appliances such as dry-cell batteries, fluorescent light bulbs and switches; and in thermometers. kidneys, brain, and nervous system) (cause serious damage to the
  54. 54. Chemicals from agricultural activities Nitrate and nitrite NO3 - and NO2 - 50 and 3 mg/L • (methaemoglobinaemia, or “bluebaby syndrome”) • There is some evidence that nitrite can react with amines or amides in the body to form nitrosamine, a known carcinogen • WHO recommends a GV of 0.2 mg/L nitrite for long-term exposure Ammonia, NH3, NH4 • Ammonia is present in nature as part of the Nitrogen Cycle. • Ammonia, at certain concentrations, is toxic to fish and is therefore considered a pollutant to waters classified for fish and wildlife. • Ammonia is primarily in the NH3 or gaseous form below pH 7.0 and primarily in the NH4+ or ammonium salt form above a pH of 7 • Nitrification Ammonium Oxidation HN4+ + 1/2O2 = NO2- + HOH + 2H+ Nitrite Oxidation NO2- + 1/2O2 = NO3• Denitrification: NO3- -----> NO -----> N2O -----> N2 gas
  55. 55. Nitrogen cycle
  56. 56. Trace organics • Over 600 organic compounds have been detected in raw water sources and most of them are due to human activity or industrial operations. • Substances include benzene, chlorophenols, pesticides, polynuclear aromatic hydrocarbons (PAH) and trihalomethanes (THM). • present in very low concentrations, but there is some concern about possible health effects
  57. 57. Pesticides • Pesticides may enter surface water or groundwater primarily as runoff following application to crops, though inappropriate disposal or accidental release • The potential of a pesticide to contaminate drinking water is affected by its solubility and biodegradability; the method of application; and environmental factors such as soil, weather, season and proximity to water resources. • Early pesticides were compounds of toxic metals such as arsenic, mercury, copper or lead • The first organic pesticides were chlorinated hydrocarbons such as DDT, aldrin, dieldrin, chlordane, endrin, heptachlor, lindane and pentachlorophenol. • they are resistant to biodegradation and can accumulate in food supplies • most commonly used pesticides today include organophosphorus compounds and carbamates, both of which are relatively soluble and biodegradable.
  58. 58. Chemicals from water treatment and distribution systems • • • • Disinfectants – Free chlorine (target residual concentration in the range of 0.2 to 1 mg/L ) – Chloramines (a mixture of monochloramine, dichloramine and trichloramine formed when ammonia is present in chlorinated water) – Silver has a bacteriostatic effect and is sometimes used for emergency disinfection (skin and hair become discoloured) – chlorine dioxide, iodine, and ozone. WHO has not set guideline values for these compounds either because they decay rapidly in water Disinfectant by-products (DBPs) i.e trihalomethanes, brominated, haloacetic acids, halogenated ketones and haloacetonitriles - WHO has set GVs for 14 DBPs Contaminants from treatment chemicals (Aluminum causes Alzheimer’s disease , Iron) Contaminants from pipes and fittings (organic compounds and heavy metals i.e copper, lead)
  59. 59. Chemical Indicator Tests • • developed to indicate water quality based on chemical characteristics which can be simpler, less expensive, or more indicative of water quality than a chemical compound test. CaCO3 is used as a standard for many of the indicator tests since its molecular weight is 100 and calculations are simplified
  60. 60. pH • pH is the negative logarithm of the hydrogen ion concentration in water. • is used to indicate the intensity of the acidic or basic character of a solution. • pH is normally determined electrometrically, but can be estimated using titration or litmus paper. • Water is only weakly ionized, as shown by the equilibrium • H20 ~ H + + OH• 10-7 molar concentrations of H + and OH- are present at equilibrium [H +] [OH-] = K = 1.01 X 10 -14 mole/L at 25 pH = -loglo [H +] = l o g lo 1/[H +] • pH scale from 0 to 14 with 7 as neutrality, below 7 acid and above 7 alkaline • Many chemical reactions are controlled by pH and biological activity is usually restricted to a fairly narrow pH range of 5-8 • Highly acidic or highly alkaline waters are undesirable because of corrosion problems and possible difficulties in treatment
  61. 61. Acidity • • • • • The acidity of water is an indicator of its capacity to react with a strong base to a designated pH. Acidity or low pH of drinking water is usually a result of natural geological conditions at the site, possibly compounded by acid rain Water with a pH value less than 7 indicates acidity and tends to be corrosive The concept of acidity is opposite that of alkalinity and is also based on the carbonate system. The acidity of a water source is generally attributable to the carbonate molecules H2CO3 and HCO3- and sometimes to strong acids, namely, H+. H+ + OH- –-> H2O; H2CO3 + OH- –-> HCO3-; HCO3- + OH- –-> CO32- When there are mostly acidic carbonate molecules in solution (H2CO3, HCO3-, and H+), the pH is correspondingly acidic (< 7) • if the carbonate molecules in solution are mostly HCO3-, CO32-, and OH-, the pH is correspondingly basic (< 7). •
  62. 62. Alkalinity Alkalinity is a function of the carbonate (CO32-), bicarbonate (HCO3-) and hydroxide (OH) content of water. • Titration with a standard acid to an end point of 8.3 PH is reported as phenolphthaline alkalinity and titration to an end point of approximately 4.5 is reported as total alkalinity. • Most of the natural alkalinity in waters is due to HCO3- produced by the action of groundwater on limestone or chalk CaCO3 + H20 + CO2 ~ Ca(HCO3)2 • • Alkalinity is useful in waters in that it provides buffering to resist changes in pH. • It is normally divided into caustic alkalinity above pH 8.2 and total alkalinity above pH 4.5. • Alkalinity can exist down to pH 4.5 because of the fact that HCO 3- is not completely neutralized until this pH is reached. • The amount of alkalinity present is expressed in terms of CaCO 3. Alk T = [HCO3-] + 2[CO32-] + [OH-] - [ H+ ]
  63. 63. Effects of pH on Various Buffers • • Mixture of an acid (or base) and its conjugate base (or acid) chemical equilibrium: CO2 + H2O ↔ H2CO3 • H2CO3 ↔ HCO3- + H+ • HCO3- ↔ CO32- + H+ • CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+ ↔ CO32- + 2 H+
  64. 64. Alkalinity and pH relationship • • • • • • OH- is a strong base - HCO3- is a weak acid more OH- than HCO3-, it completely neutralizes it and just have OHmore HCO3- than OH-, then it partially neutralizes it and detect only HCO 3Waters with low alkalinity are very susceptible to changes in pH. Waters with high alkalinity are able to resist major shifts in pH. As increasing amounts of acid are added to a water body, the pH of the water decreases, and the buffering capacity of the water is consumed
  65. 65. Conductivity vs. Total dissolved solid • Conductivity is a quantification of the ability of water to carry an electric current. • Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. This includes anything present in water other than the pure water (H20) molecule and suspended solids.
  66. 66. Main ions in natural water
  67. 67. Hardness • Total hardness is the sum of calcium and magnesium concentrations expressed in mg/l of CaCO3. • • It is a measure of the capacity of water to precipitate soap. Hardness is either calculated from the results of separate calcium and magnesium tests or is determined from a color change when titrating a sample with ethylenediaminetetracetic acid (EDTA). Hardness may actually have a health benefit, but economic disadvantages of a hard water include increased soap consumption and higher fuel costs. Hardness is expressed in terms of CaCO3 and is divided into two forms, • • – carbonate hardness: due to metals associated with HCO3– non-carbonate hardness: due to metals associated with SO42-, CI-, NO3-. • • The non-carbonate hardness is obtained by substracting the alkalinity from the total hardness. If high concentrations of sodium and potassium salts are present, the noncarbonated hardness value may be negative, since such salts could form alkalinity without producing hardness.
  68. 68. Hardness calculation The calcium and magnesium hardness is the concentration of calcium and magnesium ions expressed as equivalent of calcium carbonate. The molar mass of CaCO3, Ca2+ and Mg2+ are respectively 100,1 g/mol, 40,1 g/mol and 24,3 g/mol. The ratio of the molar masses are: • So total permanent water hardness expressed as equivalent of CaCO3 can be calculated with the following formula: • The following values are used to give an indication about the water hardness: Concentration as CaCO3 Indication 0 to 60 mg/L 60 to 120 mg/L 120 to 180 mg/L >180 mg/L Soft water Moderately hard water Hard water Very hard water
  69. 69. Other Pollutants indicators • Hydrocarbons will be indicated as oil and grease. A mixture of all oils and grease in trichlorofluoroethane can be added to silica gel to selectively remove the fatty acids and leave only hydrocarbons for indication. • Oil and Grease. Most oil and grease tests quantify substances which are soluble in trichlorotrifluoroethane. These tests will include the presence of certain sulfur compounds, organic dyes and chlorophyll that are not volatilized. • Organic Pollutants. There are three tests commonly used to measure the total organic pollutants present in a wastewater; biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC).
  70. 70. (Dissolved oxygen (DO • Oxygen is a most important element in water quality control. • Oxygen is essential to maintain the higher forms of biological life and the effect of a waste discharge on a river • oxygen is only slightly soluble in water as indicated below for water with no chloride content • Oxygen solubility is affected by the presence of chlorides which reduce the saturation dissolved oxygen concentration • Clean surface waters are normally saturated with DO, but such DO can be removed rapidly by the oxygen demand of organic wastes. • Game fish require at least 5 mg/l DO and coarse fish will not exist below about 2 mg/1 DO. • Oxygen saturated waters have a pleasant taste and waters lacking DO have boring taste; • For boiler feed waters DO is undesirable because its presence increases the risk of corrosion.
  71. 71. BIOLOGICAL POLLUTANTS • Living organisms play major roles in many aspects of water quality control • the bacteriological analysis of drinking water supplies usually provides the most sensitive quality assessment. • Raw sewage contains millions of bacteria per milliliter • Conventional treatment methods for sewage and organic wastewaters rely on the ability of microorganisms to stabilize organic matter • Microorganisms can play valuable roles in wastewater treatment and sometimes also in water treatment, • Biological pollutants have a combination of inorganic and organic constituents and are characterized by being cellular in nature. • For biological treatment purposes, only the organic constituents can be destroyed, and since all cellular material uses oxygen for energy, tests involve the measurement of either carbon content or oxygen demand, or an actual bacterial count.
  72. 72. Organic compounds • Organic compounds are generally unstable and may be oxidized biologically or chemically to stable, relatively inert, end products such as CO2, NO3, H20. • An indication of the organic content of a waste can be obtained by measuring the amount of oxygen required for its stabilization using 1. biochemical oxygen demand (BOD) - a measure of the oxygen required by microorganisms whilst breaking down organic matter; 2. chemical oxygen demand (COD) - chemical oxidation using boiling potassium dichromate and concentrated sulphuric acid.
  73. 73. )Biochemical Oxygen Demand (BOD • Biochemical oxygen demand or BOD is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. • It is most commonly expressed in milligrams of oxygen consumed per liter of sample during 5 days of incubation at 20 °C. • The BOD indicates the total of carbonaceous and nitrogenous oxygen demand. • Dissolved oxygen is measured initially after dilution and after incubation at 20°C for the time period of the test. • It is necessary to have a population of microorganisms present that is capable of degrading the organic material in the sample. • Many unchlorinated domestic or industrial wastewaters will afford sufficient bacteria for this purpose.
  74. 74. (The Chemical Oxygen Demand (COD • The Chemical Oxygen Demand (COD) test is a measure of the oxygen required from a strong chemical oxidant for the destruction of an organic material. • The chemical oxidant selected for the COD test is potassium dichromate (K2Cr2O7). • The sample is oxidized by a boiling mixture of K2Cr2O7 and sulfuric acid using an excess of K2Cr2O7. • After digestion, the remaining unreduced K2Cr2O7 is measured to determine the amount consumed by titrating with ferrous ammonia sulfate (FAS) until the end point is indicated by a sharp color change. • The COD takes about 2 to 3 hours to run compared to 5 days for a BOD test, and can be run with a relatively simple and inexpensive kit.
  75. 75. Total Organic Carbon and Total Carbon • Total Organic Carbon (TOC) test is a more direct indication of organic content than the BOD or COD test. • If a repeatable relationship between the three parameters is determined, TOC can be used to estimate the other parameters. • The TOC test does not provide all of the information that the BOD and COD tests provide. • The BOD test indicates the actual oxygen needed for biologically destroying the organic. • The COD test indicates the chemical oxidation requirements for destruction, • the TOC test indicates the total organic matter present and is independent of the oxidation state of the pollutant. • This test converts and removes inorganic carbon (CO + CO 2) and measures total organic carbon by converting it into CO2 in a heated reaction chamber. • The CO2 is measured using infrared methods.
  76. 76. Theoretical Oxygen Demand • The Theoretical Oxygen Demand (ThOD) is the determination of oxygen needed to convert all carbon molecules in pollutants to CO2, and all NH3 and NO2- to NO3- by balancing equations. • This calculation is possible on certain rather pure industrial wastes, but is impractical for most wastewaters, especially those containing domestic sewage or containing vegetable or animal wastes.
  77. 77. Theoretical Oxygen Demand/ Example In order to determine the ThOD for glycine (CH2(NH2)COOH) using the following assumptions: 1. In the first step, the organic carbon and nitrogen are converted to carbon dioxide (CO2) and ammonia (NH3), respectively. 2. In the second and third steps, the ammonia is oxidized sequentially to nitrite and nitrate. 3. The ThOD is the sum of the oxygen required for all three steps. • 1. Write balanced reaction for the carbonaceous oxygen demand. CH2(NH2)COOH + 1.5 02 ->NH3 + 2CO2 + H20. • Write balanced reactions for the nitrogenous oxygen demand. NH3 + 1.5 02 -> HNO2 + H20 HNO2 + 0.5 O2 -> HNO3 summation NH3 + 2 O2 -> HNO3 + H2O. • Determine the ThOD. • ThOD= (1.5 + 2) mol O2/mol glycine = 3.5 mol O2/mol glycine • ThOD = 3.5 mol O2/mol glycine x 32 g/mol O2 / 75 g/mol glycine = 1.49 g O2/g glycine
  78. 78. Relationship between BOD, COD, TOC and ThOD BODu = 0.9ThOD Where BODu = ultimate BOD • BODu = 0.9ThOD because (approximately ten percent of the original organics remain as non-biodegradable cellular residues after biological oxidation) BOD5 = 0.77BODu • BODu is much greater than BOD5 because much of the easily degraded material would have been removed in the sewage treatment process and many industrial processes discharge difficult to degrade organic molecules • For most wastewaters: ThOD = COD • Stoichiometrically, the COD/TOC ratio should be approximately the molecular ratio of oxygen to carbon: • The BOD5 to COD ratio for domestic waste and certain biodegradable industrial wastes can be computed as follows:
  79. 79. Microbiological contamination • Microbiological water quality monitoring is primarily based on tests for indicator organisms Characteristics of the Ideal Faecal Indicator • Should be present in wastewater and contaminated water when there are pathogens • Should be present when there is a risk of contamination by pathogens • Should be present in greater numbers than the pathogens • Should not multiply in environmental conditions under which pathogens cannot multiply • The indicator population should correlate with the degree of faecal contamination. • The survival time in unfavorable environmental conditions should exceed that of pathogens • Should be more resistant to disinfectants and other stresses than the pathogens • Should present no health risk • Should be easy to enumerate and identify by simple methods • Should have stable characteristics and give consistent reactions in these analyses
  80. 80. Escherichia coli • This species is a member of the group of faecal coliform bacteria. • Escherichia coli (E. coli), a rod-shaped member of the coliform group • Escherichia coli has the important feature of being highly specific for the faeces of man and warm-blooded animals. • These bacteria cannot multiply in any natural water environment and they are, therefore, used as specific indicators for faecal pollution. • They are generally distinguished from other thermotolerant coliforms by the ability to yield a positive indole test within 24 hours at 44.5°C. • E. coli are almost exclusively of fecal origin and their presence is thus an effective confirmation of fecal contamination.
  81. 81. Thermotolerant coliform bacteria • certain members of the group of total coliform bacteria which are more closely related to faecal or sewage pollution, and which generally do not readily replicate in water environments. • This group of bacteria is also known as faecal coliforms, presumptive E. coli, faecal E. coli, faecal coli, etc. • Thermotolerant coliforms are primarily used for the assessment of faecal pollution in waste water and raw water sources. Detection of faecal streptococci
  82. 82. (Coliform bacteria (total coliforms • The term "coliform bacteria" refers to a vaguely defined group of Gram-negative bacteria which have a long history in water quality assessment. • Coliform bacteria are microorganisms that primarily originate in the intestines of warmblooded animals • Some of the bacteria included in this group are almost conclusively of faecal origin, while other members may also replicate in suitable water environments. • The primary purpose of coliform tests is not to detect faecal pollution but to screen the general sanitary quality of treated drinking-water supplies.
  83. 83. Enterococci ** Enterococci are facultative anaerobic organisms. i.e., they are capable of cellular respiration in both oxygen-rich and oxygen-poor environments ** Sometimes referred to as faecal streptococci, is a group of bacteria more closely related to faecal pollution than total coliforms because most members of this group do not replicate as readily in water environments ** Enterococcus spp. took the place of fecal coliform as the new standard in USA for water quality at public beaches ** It is believed to provide a higher correlation than fecal coliform with many of the human pathogens often found in city sewage they are not capable of forming spores, enterococci are tolerant of a wide range of environmental conditions: extreme temperature (1045°C) , pH (4.5 – 10 ( and high sodium chloride concentrations
  84. 84. Sulphite-reducing clostridia • Gram-positive bacteria (those that are stained dark blue or violet by Gram staining), anaerobic bacteria • Their spores are more resistant to conditions in water environments, as well as treatment and disinfection processes, than most pathogens, including viruses. • Clostridia are sometimes considered as too resistant, and their inclusion in water quality guidelines as too stringent. • One of the members of the group, Clostridium perfringens, is like E. coli highly specific for faecal pollution. • Clostridia generally occur in lower numbers in waste water than coliform bacteria. • Detection methods are relatively expensive and time-consuming.
  85. 85. Discrepancies The coliform index is far from perfect. • Thermotolerant coliforms can survive in water on their own, especially in tropical regions, so they do not always indicate fecal contamination. • they do not give a good indication of how many pathogenic bacteria are present in the water, • they give no idea at all of whether there are pathogenic viruses or protozoa which also cause diseases and are rarely tested for. • Therefore, it does not always give accurate or useful results regarding the purity of water.
  86. 86. Human viruses Differ from that of faecal indicators for reasons such as: • Viruses are excreted only by infected individuals, and coliform bacteria by almost all people and warm-blooded animals. • Numbers of viruses in water environments are generally lower than those of indicators such as faecal coliforms by several orders of magnitude. • Viruses are excreted for relatively short periods • The structure, composition, morphology and size of viruses differs fundamentally from that of bacteria • Bacterial indicators such as coliform bacteria have shortcomings as indicators for viruses. • Unfortunately, tests for viruses are relatively expensive, complicated and time consuming, and require sophisticated facilities and know-how. • Control of the virological safety of water is based on raw water quality and specifications for purification and disinfection processes rather than testing of the treated water
  87. 87. Coliform Bacteria Test • Multiple Tube Coliform Tests • Membrane Filter Coliform Test
  88. 88. Toxicity Tests • The purpose is to determine the concentration of a pollutant which can exist in a body of water that will neither kill a test organism (acute toxicity) nor prevent reproduction (chronic toxicity) of the organism. • After this determination, an application factor is usually multiplied by the test results to obtain a permit limit. • Commonly used application factors are 0.01 if the pollutant is cumulative in the internal organs, and 0.10 if the pollutant is not cumulative. • The most common toxicity tests are for daphnia and fish. • Acute toxicity describes the adverse effects of a substance which result either from a single exposure or from multiple exposures in a short space of time (usually less than 24 hours( • Chronic toxicity is a property of a substance that has toxic effects on a living organism, when that organism is exposed to the substance continuously or repeatedly.
  89. 89. Toxicity Tests • In toxicology, the median lethal dose, LD50 (abbreviation for “Lethal Dose, 50%”), LC50 (Lethal Concentration, 50%) or LCt50 (Lethal Concentration & Time) of a toxic substance or radiation is the dose required to kill half the members of a tested population after a specified test duration. • LD50 of a substance is given in milligrams per kilogram of body weight. • Measures such as 'LD1' and 'LD99' (dosage required to kill 1% or 99% respectively of the test population) are occasionally used for specific purposes.
  90. 90. Typical characteristics of water
  91. 91. Typical Domestic Wastewater Compositions
  92. 92. Sampling Grab Sample • is a sample taken at one time in one quantity which is deemed representative of the flow and pollutant concentration. • must be taken from a well mixed area to allow all settleable and floatable solids to be included in the sample. Composite Samples. • is one which is taken proportional to either time or flow. • A time composite sample takes an equal quantity of sample each period of time. • To be truly proportional, this type of sample should be taken only when pollutant concentrations are uniform over the time period in which the samples are taken. • The automatic sampler can be adjusted to either take a discrete sample with time or to add a certain sized sample to a large container at each time period. • This sampler can be packed with ice to preserve the sample for biological sampling.
  93. 93. Analytical methods • Gravimetric analysis: analysis depends upon weighing solids obtained from the sample by evaporation, filtration or precipitation • Volumetric analysis : An example of the use of volumetric analysis is found in the determination of alkalinity and acidity • Colorimetric analysis • Visual methods • Instrumental methods (Absorptiometer , Spectrophotometer, Flame photometer, Atomic Adsorption) • Electrode techniques: ion electrodes for determinations such as NH 4+, NO3-, Ca2+, Na+, CI-, Br-, F-, etc. • Automated analysis, remote monitoring and sensing
  94. 94. Water Quality / TYPES OF RECEIVING WATERS • Lakes: is classified as a pool of water, which is trapped behind a natural or artificial dam that normally causes the pool to be contained Lake Stratification: • The density of water is greatest at 4°C • colder water tends to sink in a lake • In Summer: Sunlight heats the upper layers of water - the deeper water remains cold – (thermocline) • the thermocline is a narrow vertical zone between the warmer and colder waters where a rapid temperature change occurs. • In Fall: the surface of the lake reaches a temperature close to 4°C - a strong wind will overturn the lake stratification and the lake becomes unstratified • Spring overturn (unstratified)
  95. 95. Lake stratification
  96. 96. Lake Eutrophication • Oligotrophic: Normal lakes have minimal levels of nutrients are said to be enriched - Oligotrophic • Eutrophication is the enrichment of water by nutrients; a lake that is enriched is said to be eutrophic • eutrophic lakes contain large populations of aquatic animals • unenriched lake there is a higher concentration of dissolved oxygen • eutrophic lakes the deeper, colder levels of water are depleted of dissolved oxygen because of the high BOD caused by decomposition on the lake floor • As natural eutrophication occurs, these bodies of water are slowly enriched and grow shallower from the immense number of dead organisms • Eutrophication can be markedly accelerated by human activities, and it results from the enrichment of water by inorganic plant and algal nutrients- most commonly in sewage and fertilizer runoff.
  97. 97. Oligotrophic lake and a eutrophic lake
  98. 98. Rivers and Streams • • • • Rivers are uncontrolled by dams, the water level will be directly proportional to stormwater and the rivers can have a tremendous variation in flow. A very slowly moving river can stratify similarly to a lake. Rivers and streams will tend to re-aerate themselves In order to aid in pollutant distribution from an outfall, some permits may require an outfall to discharge at several locations across a river.
  99. 99. Intermittent Streams – Ditches – Estuaries - Saltwater • Intermittent stream is a stream that only flows during wet weather • These streams will have very stringent permit levels if the intermittent streams contain aquatic life which can exist in intermittent water flow conditions and would be damaged by pollutant discharge. • Also the permit levels should be controlled by the downstream conditions in a lake, river or stream. • Ditches are artificially created channels (lined or not) • Like intermittent natural streams, ditches have a zero low flow and stringent permit limits. • Estuaries are the transition areas between fresh water and salt water and contain much unique aquatic life. • Saltwater: Oceans, gulfs, etc. are highly saline and contain unique marine aquatic life. Regulations are gradually being made more strict for saltwater environments as more is discovered about their sensitive environments.
  100. 100. Groundwater
  101. 101. SIGNIFICANT DETERIORATION OF WATER QUALITY • Navigation • Recreation • Irrigation • Fish and Aquatic Life • Domestic and Drinking purposes (Health)
  102. 102. Water quality and health WHO data give an indication of the magnitude of the problem • each year over five million people die from water-related diseases • two million of the annual deaths are of children • in developing countries 80 per cent of all illness is water-related • at any one time half of the population in developing countries will be suffering from one or more of the main water-related diseases • a quarter of children born in developing countries will have died before the age of five, the great majority from water-related disease. • At any one time there are likely to be 400 million people suffering from gastroenteritis, 200 million with schistosomiasis and 160 million with malaria. All of these diseases can be water-related although other environmental factors may also be important.
  103. 103. Microbiological contamination • Bradley classification system for water-related diseases
  104. 104. Guideline values for verification of microbial quality
  105. 105. Water-borne diseases • Definition: water-borne diseases are diseases caused by the ingestion of water contaminated by human or animal faeces or urine containing pathogens. • Many bacteria, viruses, protozoa and parasites can cause disease when ingested. • The majority of these pathogens derive from human or animal faeces, and are transmitted through the faecal-oral route. • both animal and human faeces are threats to human health, human faeces are generally the most dangerous. • Faecal pathogens can be classified as causing both water-borne and water-washed diseases. • 4.2 million deaths per year (mostly in children under 5) from diarrhoeal disease from 1955-1979 dropping to 3.3 million per year from 1980-1989, and 2.5 million per year from 1992-2000 • Examples: Typhoid fever is caused by ingestion of Salmonella typhi bacteria – Hepatitis A and E
  106. 106. Water-washed diseases • Definition: water-washed diseases are diseases caused by inadequate use of water for domestic and personal hygiene Examples: Soil-transmitted helminths: ascaris, hookworm ‫ الديدان الخطافة‬and whipworm ‫( الديدان السوطية‬Trichuris trichiura). • Acute Respiratory Infections: Acute respiratory infections (ARI) including pneumonia (an inflammatory condition of the lung ‫ )ذات الرئة‬are responsible for 19% of total child deaths every year. • Skin and eye diseases: Trachoma is the world’s leading cause of preventable blindness: about 6 million people are blind due to trachoma, and more than 10% of the world’s population is at risk. • Ringworm (tinea) is an infectious disease of the skin, scalp ‫فروة الرأس‬or nails. • Flea‫ , البرغوث‬lice ‫ , القمل‬mite and tick-borne diseases: Scabies is caused by the microscopic mite Sarcoptes scabei and characterized by intense itching. Scabies spreads rapidly, and causes an estimated 300 million cases each year.
  107. 107. Water-based diseases and Water-related diseases • Water-based diseases: are infections caused by parasitic pathogens found in aquatic host organisms. • Eg. Schistosomiasis is a major parasitic disease in tropical and sub-tropical regions, second only to malaria in terms of socio-economic and public health importance • Water-related diseases; are caused by insect vectors which either breed in water or bite near water. • not directly related to drinking-water quality • The most common vector insects are mosquitoes and flies like: – Mosquito-borne diseases (malaria - yellow fever) – Fly-borne diseases (onchocerciasis (river-blindness) - trypanosomiasis (West African sleeping sickness)
  108. 108. Morbidity and mortality rates of some important water-related )diseases (after WHO, 1995
  109. 109. Graphical Methods • every groundwater investigation involves a determination of both the quantity of water available and the quality of the water • The graphical methods used to facilitate the interpretation and presentation of chemical analysis. Types of Graphical representations: • Box and Whisker Plot - Multiple Parameters / Multiple Stations • Depth Profile Plot • Frequency Histogram • Ludwig-Langelier Plots • Pie Charts • Piper Diagrams • Radial Diagrams • Scatter Plots • Schoeller Plots • Stiff Diagrams • Site Map Diagrams • Ternary Diagrams • Time Series Plots - Multiple Stations / Multiple Parameters • Wilcox Diagram
  110. 110. Graphical Methods / Box and Whisker Plot - Multiple Parameters and Multiple Stations • The Box and Whisker - Multiple Parameters plot displays a statistical summary of multiple measured database parameters, at a selected station location. • The Box and Whisker - Multiple Stations plot displays a statistical summary of any measured database parameter, at multiple station locations. The plot displays the following statistical analyses: • The minimum measured value; • Q1: the first (lower) quartile (25th percentile): 25% of the data lie below this value; • Q2: the second quartile (Median): 50% of the data lie below this value; • Q3: the third (upper) quartile (75th percentile): 25% of the data lie above this value; • The maximum measured value
  111. 111. Graphical Methods / Box and Whisker Plot - Multiple Parameters and Multiple Stations
  112. 112. Depth Profile Plot • • the plot displays the change of a measured parameter over a measured sampling depth. The plot can be used to plot all samples in the open database or selected sample groups.
  113. 113. Durov Diagrams • • • • The Durov diagram plots the major ions as percentages of milli-equivalents in two base triangles. The total cations and the total anions are set equal to 100% and the data points in the two triangles are projected onto a square grid which lies perpendicular to the third axis in each triangle. This plot reveals useful properties and relationships for large sample groups. The main purpose of the Durov diagram is to show clustering of data points to indicate samples that have similar compositions.
  114. 114. Frequency Histogram • used to check the number of populations within a given range of measured values. • The frequency of samples within the given ranges can be plotted according to percentages or numbers of samples. • The range of values can be customized up to 10 or more groups and the individual samples can be identified at the associated value along the x-axis.
  115. 115. Ludwig-Langelier Plots • • • • • • Suitable groupings of cations and anions are selected and plotted as percentages of milli-equivalents. By convention, the sums of the selected cations are plotted on the y-axis, and the sum of the selected anions are plotted on the x-axis. Each axis ranges from 0 to 50 meq%. All major elements can be displayed in one plot. it displays relative ratios rather than absolute concentrations. The Ludwig-Langelier diagram can be used to plot all samples in the open database or selected sample groups.
  116. 116. Pie Charts • Is used to plot the concentrations ratio of the major ions (or any combination of parameters) for individual samples. • is used to graphically compare the concentration ratios of several measured parameters for several different samples. • The color and patterns used to identify each parameter are customizable
  117. 117. Piper Diagrams • • • • • • • • • • • is a graphical representation of the chemistry of a water sample or samples. The Piper diagram plots the major ions as percentages of milli-equivalents in two base triangles. The cations and anions are shown by separate ternary plots. The apexes of the cation plot are calcium, magnesium and sodium plus potassium cations The apexes of the anion plot are sulphate, chloride and carbonate plus hydrogen carbonate anions. The two ternary plots are then projected onto a diamond. The diamond is a matrix transformation of a graph of the anions (sulfate + chloride/ total anions) and cations (sodium + potassium/total cations). The total cations and the total anions are set equal to 100% and the data points in the two triangles are projected onto an adjacent grid. This plot reveals useful properties and relationships for large sample groups. The main purpose of the Piper diagram is to show clustering of data points to indicate samples that have similar compositions. The Piper diagram can be used to plot all samples in the open database or selected sample groups.
  118. 118. Piper Diagrams Figure 1 from Kehew (2001). Water analyses plotted on a Piper diagram. Cation percentages in meq L-1 plotted on the left triangle, and Anion percentages in meq L-1 plotted on the right triangle.
  119. 119. Water types using piper diagram
  120. 120. Radial Diagrams • Radial diagrams are plotted for individual samples as a method of graphically comparing the concentrations of measured parameters for several individual samples. • The shape formed by the Radial diagrams will quickly identify samples that have similar compositions and are particularly useful when used as map symbols to show the geographic location of different water facies
  121. 121. Scatter Plots • • • • the most simple initial approach to the interpretation of geochemical data. Single plots of ion relationship and parameters that show significant data can be easily created and patterns are quickly identified and easily understood. Both normal scale and log scales are supported for the x and y axes and multiplication factors can be applied to either the x or y parameter. Parameter ratios and sums may also be included for either axes.
  122. 122. Schoeller Plots • These semi-logarithmic diagrams were developed to represent major ion analyses in meq/l and to demonstrate different hydrochemical water types on the same diagram. • This type of graphical representation has the advantage that, unlike the trilinear diagrams, actual sample concentrations are displayed and compared. • Up to 10 different parameters can be included along the x-axis
  123. 123. Stiff Diagrams • • Is used to display the major ion composition of a water sample. A polygonal shape is created from four parallel horizontal axes extending on either side of a vertical zero axis. • Cations are plotted in milliequivalents per liter on the left side of the zero axis, one to each horizontal axis, and anions are plotted on the right side. • Stiff patterns are useful in making a rapid visual comparison between water from different sources. Stiff diagrams can be used: • 1) to help visualize ionically related waters from which a flow path can be determined, or; • 2) if the flow path is known, to show how the ionic composition of a water body changes over space and/or time. • When comparing Stiff diagrams between different waters it is important to prepare each diagram using the same ionic species, in the same order, on the same scale. • to convert the mass concentration mg/L to an equivalent concentration (mass conc.)*(ionic charge)/(molecular weight)=(equivalent conc.) • Example, a water with a calcium concentration of 120 mg/L would have the following calcium equivalent concentration: (120 mg/L) * (2 meq/mmol) / (40 mg/mmol) = (5 meq/L)
  124. 124. Stiff Diagrams Pine Creek, CDA Valley, Idaho Mine Waters Cations 15 10 meq/l Anions 5 5 Na+K 15 Cl AD002 Ca 10 HCO3+CO3 Mg SO4 Na+K Cl HCO3+CO3 AD004 Ca Mg An example of a Stiff diagram drawn for mine waters from the Pine Creek district, Coeur d’Alene Valley, ID. The anions are mostly dominated by sulfate, with lesser bicarbonate, whereas the cations are dominated by calcium and magnesium. SO4 Na+K Cl Ion concentrations in meq L-1 are plotted on the HCO3+CO3 AD005 Ca Mg SO4 Na+K Cl Ca AD007HCO3+CO3 Mg Na+K SO4 Cl S97-3 Ca HCO3+CO3 Mg SO4 Na+K Cl Ca SP002 HCO3+CO3 Mg SO4 Na+K Cl Ca HCO3+CO3 SPNEW Mg SO4 horizontal axis. Cations are plotted to the left, anions to the right, of a vertical axis. The data are plotted in four rows and the points are connected to form a polygon. Advantage: each water type produces a distinct shape. Disadvantage: each analysis requires its own plot; only a limited number of data can be shown on a single plot.
  125. 125. Site Map Diagrams • Sample locations can be displayed on an X-Y graph and a detailed site maps can be imported from AutoCAD DXF files to provide a familiar point of reference when you are analyzing sample data. • the map plot can be used to display the location of different water types, or the symbols can be scaled in color or in size according to the concentration of a selected measured element
  126. 126. Ternary Diagrams • • • • is used to identify trends and relationships between groups of samples. it is easier to understand than Piper or Durov diagrams since it involves fewer parameters and does not project data points onto a grid. Like the Piper diagram, the Ternary diagram plots the ions as percentages of their concentration values. is not limited to using only meq units.
  127. 127. Time Series Plots - Multiple Stations • This Time Series plot displays the evolution of a physical or chemical parameter for multiple sampling locations, as a function of time. • This plot is a standard technique for interpreting hydrochemical and hydrogeological processes in natural waters.
  128. 128. Time Series Plot - Multiple Parameters • This Time Series plot displays the evolution of multiple chemical or physical parameters for a given sampling point as a function of time.
  129. 129. Wilcox Diagram • Can be used to quickly determine the viability of water for irrigation purposes. • The Wilcox plot is a simple scatter plot of Sodium Hazard (SAR) on the Y-axis vs. Salinity Hazard (Cond.) on the X-axis. • The Conductivity (COND) is plotted by default in a log scale. • The Wilcox plot has the following sections: • Conductivity (us/cm): • C1: Low (0-249) • C2: Medium (250-749) • C3: High (750-2249) • C4: Very High (2250-5000) • The SAR values are divided into the following categories: • S1: Low • S2: Medium • S3: High • S4: Very High
  130. 130. Wilcox Diagram