1. Water Quality Chapter 6 Water Sources
WQT 121
Lecture 1

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3. Objectives Review Principle Water Quality Characteristics
Reading assignment:
Handout: Chapter 6 Water Quality
Review Principle Water Quality Characteristics
Understand common secondary MCLS.
Effect of pH, Taste, Odor, Corrosion on water quality
Review of MCLS & key contaminants in water
4. Hard verse soft water

4. Mineralogical Analysis of Water
Concentration (Mg/L) Quantity of a constituent in a standard volume (1 liter) is measured by its weight (in milligrams). 1 ppm (old school) = 1mg/L (correct)
General Mineral Content Ca, Na, Mg, Fe, Mn, HCO3, CO3, SO4 and Cl2.
Rivers < 500 mg/L to 2,000 mg/L
Groundwater ,000 mg/L

5. In the water treatment field, mg/L and ppm are considered to be equivalent units.
True
False

6. 3.5% salinity or 35,000 TDS (mg/L), 10,5000 mg/L Na, 19,700 mg/L Cl2, 2,650 mg/L SO4, 1,310 mg/L Mg, Ca 410 mg/L, Br 65 mg/L, Bicarbonate 152 mg/L, pH 8.1
Rainwater
Seawater
Lake Water
Groundwater

7. Groundwater in comparison to surface water is generally:
Lower in turbidity and higher in mineral content
Higher in turbidity and lower in mineral content
More susceptible to seasonal changes
More susceptible to algal blooms
Warmer and is quite soft

8. 7. 1 TDS mg/l, 7 mg/L Na, 1 mg/L Cl2, 2 mg/L SO4, 0. 74 mg/L Mg, Ca 5
7.1 TDS mg/l, 7 mg/L Na, 1 mg/L Cl2, 2 mg/L SO4, 0.74 mg/L Mg, Ca 5.5 mg/L, pH 6.9
Rainwater
Seawater
Lake Water
Groundwater

9. 180 TDS mg/l, 7 mg/L Na, 23 mg/L Cl2, 40 mg/L SO4, 8
180 TDS mg/l, 7 mg/L Na, 23 mg/L Cl2, 40 mg/L SO4, 8.6 mg/L Mg, Ca 53 mg/L, pH
Rainwater
Seawater
Lake Water
Groundwater

10. Key Words
Dissolved Solids very stable inorganic or organic substances that remain in suspension.
Colloidal Solids Tiny clay and organic materials that float in water and repel each other.
Suspended Solids Large particles of silt and sand that settle out in a sedimentation basin or clarifier.
National Secondary Drinking Water Regulations (NSDWRs): are non‑enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water

11. Turbidity and Corrosion
Turbidity: A measure of the light scattering property of water
The unit of measure is the NEPHELOMETRIC TURBIDITY UNIT, or NTU.
Corrosion: The destruction of metal by electro-chemical processes.
Corrosion is simply natures way to return metals back to their natural state: OXIDES

12. Corrosion Factors
Low pH, which is often associated with EXCESS CARBON DIOXIDE in water
High oxygen
High total dissolved solids (salts) in the form of chlorides or sulfates
Soft water, or low hardness water
High temperature often exaggerates corrosion problems
6. Low alkalinity

13. Corrosion Controls Aggressive soil and water
Protective coatings inside and outside of pipe (cement lining is very effective for ductile iron pipe plastic wrap can effectively protect ductile iron pipe from soil corrosion)
2.Cathodic protection, using zinc or magnesium sacrificial anodes to coat
3.Adjust water chemistry by increasing the pH, adding alkalinity, or adding hardness ions
4. Galvanic corrosion
Electro-chemical process similar to a battery that occurs when dissimilar metals are joined.

14. What does TDS stand for? Total dissolved solids
Temporarily dissolved solids
Total disaggregated solids
Total dissolved salts

15. The total solids in water would be a combination of:
Fixed solids and settleable solids
Dissolved solids and volatile solids
Dissolved solids and suspended solids
Suspended solids and fixed solids
Fixed solids and dissolved solids

16. Total Dissolved Solids are dried at this temperature
103oC
105oC
180oC
550oC

17. The secondary MCL for TDS in drinking water is?
10 mg/L
500 mg/L
1,000 mg/L
1 mg/L
A ____ sample is a discrete sample that is collected manually.

18. Key Words
Turbidity A measure of the light scattering property of water (cloudiness)
The unit of measure is the NEPHELOMETRIC TURBIDITY UNIT, or NTU.
Corrosion The destruction of metal by electro-chemical processes.
Corrosion is simply natures way to return metals back to their natural state: OXIDES

19. NTU stands for? Nephelometric turbidity unit
Nephelometric total solids utilization
Nepelometric turbidity utilization
Nominal Turbidity Unit
Nominal Tubidity Utilization
A ____ sample is a discrete sample that is collected manually.

20. Turbidity is caused by? Dissolved solids Suspended particles
Dissolved gases
Dissolved colored solids
A ____ sample is a discrete sample that is collected manually.

21. Which of the following is a major part of a turbidimeter?
light
aspirator
Reference electrode
Objective nosepiece
A ____ sample is a discrete sample that is collected manually.

22. Turbidimeters must be calibrated:
Monthly
Quarterly
If factory calibrated, never
Daily
Weekly
A ____ sample is a discrete sample that is collected manually.

23. Which of the following parameters is used to indicate the clarity of water?pH
Chlorine residual
Turbidity
Bacteriological
A ____ sample is a discrete sample that is collected manually.

24. Which of the following substances will reduce the effectiveness of chlorine disinfection?
color
radon
Turbidity
Carbon dioxide
A ____ sample is a discrete sample that is collected manually.

25. According to the Interim Enhanced Surface Water Treatment Rule, a public water system serving a population of 10,000 or more must maintain the combined effluent turbidity of direct or conventional filtration 95% of all measurements taken each month at :
≤0.3 ntu
≤0.5 ntu
≤1.0 ntu
≤5.0 ntu
A ____ sample is a discrete sample that is collected manually.

26. The conductivity of the source water indicates the quantity of dissolved material present
True
False

27. In general for every 10 units of Electrical Conductance reported represents 6 to 7 mg/L increases of dissolved solids
True
False

28. Electrical Conductance is reported in mmhos/cm at 25oC.
True
False

29. Color
Apparent color: from light that is reflecting off the particles (giving it a yellow or straw color)
True color: tea color that remains after filtering (organic acids from vegetation)
Units are CU or color units

30. What is apparent color? Color in a sample after it is filtered
Color in a sample before it is filtered
Color in a sample after it is disinfected
Color in a sample before it is disinfected
A ____ sample is a discrete sample that is collected manually.

31. __________ can interfere with a turbidity meter measurement.
SS concentration pH
Color
Temperature
A ____ sample is a discrete sample that is collected manually.

32. Sludge accumulations in settling basins over a period of time usually:
Add hardness to the water
Increase the algae growth
Result in taste and odor problems
Result in the growth of pathogenic organisms
A ____ sample is a discrete sample that is collected manually.

33. As water temperatures decrease, the disinfecting action of chlorine:
Decreases
Increases
Remains the same
Depends on the altitude
As temperatures increase chemical reactions speed up
Arrhenius equation: reaction rate doubles every 10 degree celsius

34. Lake Stratification Epilimnion- top of the lake
Thermocline- middle layer that may change depth throughout the day
Hypolimnion- bottom layer
Temperature change- from season create a cyclic pattern that is repeated from year to year.

35. The formation of layers of different temperature in a body of water is called what?
Thermal stratification
Thermal justification
Limnoptic layering
Limnoptic stratification

36. Reservoir turnover is? Related to the pH of water
Caused by denser water at the surface sinking toward the bottom
Caused by wind cracking ice on the surface
Needed to control algae growth

37. Hard vs Soft Water 1. Hard Water 2. Soft Water
Hardness:
Ca+2 & Mg+2
250 mg/L
poor suds / soap ring
mineral buildup (scale)
fixture staining (white chalky)
Ion exchange softening
Lime - soda softening
sequestering agents
1. Hard Water
Hard water is any water containing an appreciable quantity of dissolved minerals. > 250 mg/L (mostly Ca+2 and Mg+2).
Precipitates on pipes, Soap hard to lather because it reacts with Ca and Mg salts in hard water. Need to use ion exchange or treat with lime
2. Soft Water
Soft water is treated water in which the only cation (positively charged ion) is sodium.

38. Drinking water average is about 250 mg/L as calcium carbonate hardness
What are typical values in nature?
Classification mg/L
Soft
Slightly hard
Moderately hard
Hard – 180
Very Hard & over
Drinking water average is about 250 mg/L as calcium carbonate hardness

39. Hardness #2340 How is it done? Before w/ After EDTA titration
indicator
After EDTA titration
To endpoint

40. Hardness #2340 hardness in mg/l as CaCO3
What are the units and conversions?
hardness in mg/l as CaCO3
Calculations and Formulas?
Hardness as CaCO3 mg/L=
(ml of EDTA (sample) – ml of EDTA (blank))(0.01 M EDTA)(100 mg=CaCO3 milliMole)(1000 ml/L)
ml of sample volume titrated

41. Hard Waters in the USA

42. Alkalinity and hardness are both analyzed by adding a known reagent to the sample. This process results in a ______ change.
Color
Temperature
Time
Ionic strength

43. This is the titrant used for the Hardness analysis.
EDTA - A Chelating Agent
0.03 N Sulfuric acid
0.125 N Hydrochloric acid
Sodium hydroxide

44. Hardness is defined as the sum of the _____ and ____ ions, although any divalent metal ion can contribute to hardness.
Calcium and Magnesium
Magnesium and Sodium
Calcium and Sulfate
Struvite

45. pH
Definition: The potential of hydrogen. Negative log of the hydrogen ion activity/concentration.
Formula pH= -log10(αH+)
The pH scale: -?
Acid Neutral Basic
The pH range for drinking water is 6.5 to 8.5

46. Some characteristics of water, such as pH and dissolved oxygen, change so quickly that they need to be measured immediately.
True
False

47. Acid-Base pH Balance
Figure 2.7

48. Which of the following pH readings indicates an acidic source water?3 7 9 12

49. A water with a pH value of 7.00 is considered to be:
Basic
Acidic
Hot
Neutral
Cold

50. When operating a surface water treatment plant, which of the following laboratory tests is of most significance for establishing chemical dosages for coagulating water?:
pH and alkalinity
Sulfates
Chlorides
Calcium and magnesium
Total hardness

51. The pH is a measure of the concentration of _____ ____ in a solution
Hydrogen ions
Hydrozide ions
Acid equivalents
Base equivalents

52. Which one of the following statements is true in regard to the concept of pH?
pH indicates the amount of total alkalinity available.
A raw water sample with a pH of 6.5 is slightly basic.
The range of pH is between 0 and 14
A pH meter gives the percent hydrogen ion concentration as its direct readout value.
Accurate pH measurements on raw water require that a 24-hour flow-proporational sample be collected.

53. pH sensors consist of A glass electrode and reference electrode
A pH electrode and temperature electrode
A junction electrode and null electrode

54. The range of a pH analyzer is
2 to 14 pH units
4 to 14 pH units
0 to 14 pH units
1 to 14 pH units

55. pH sensors measure the activity of which ion?
Sodium
Hydrogen
Chlorine
Caustic

56. What is the maximum recommended holding time for a sample that is to be analyzed for pH?
None; it must be analyzed immediately
48 hours
7 days
14 days

57. What is the minimum number of pH standards needed for calibration of a pH meter?1 2 3 4

58. Temperature does not affect pH measurement.
True
False

59. Water Properties Freezing point 0oC boiling point 100oC.
Dipolar Molecule
High surface tension= hydrogen bonding
Expands upon freezing (10%)-more dense as liquid
Freezing point 0oC boiling point 100oC.
Most abundant liquid on surface of earth
Exist in 3 phases on earth (Triple point)
Universal solvent
High heat capacity
High heat of fusion
High heat of evaporation
High heat of vaporization + -
104.5°

60. Water Impurities
Dissolved, Colloidal, and Suspended solids- (acid, base, sand, clay, organics)
Inorganic acids: sulfuric, nitric, hydrochloric, carbonic
Bases: caustic soda, soda ash, hydrated lime
Salts: ferric chloride, aluminum sulfate, sodium chloride
Organics: volatile organic compounds (VOCs), synthetic organic compound

61. SMCL
Water Quality Problem
Treatment Methods
Iron
0.3 mg/L
red water complaints
taste and odor
staining of clothing and fixtures (red -brown)
chlorine + filtration
aeration + filtration
manganese green sand + permanganate
sequestering agents
Manganese
0.05 mg/L
staining of clothing and fixtures (black or dark purple)
Hardness:
Ca+2 & Mg+2
250 mg/L
poor suds / soap ring
mineral buildup (scale)
fixture staining (white chalky)
Ion exchange softening
Lime - soda softening
Sulfate
salty off taste
temporary diarrhea
reverse osmosis / ion exchange
TDS
500 mg/L
high mineral content (salts) does not quench thirst, leaves mineral deposit
Chloride
salty taste
contributes to corrosion
Hydrogen
Sulfide
0.1 mg/L
rotten egg odor
oxidize with chlorine, chlorine dioxide or permanganate
Odor
3 T.O.N.
makes water un-palatable
permanganate
activated carbon (PAC, GAC)
flushing programs
Color
15 colorunits
effective coagulation

62. pH Effect Water Quality
Disinfection with Chlorine:
Water pH has a big impact on chlorine effectiveness. Chlorines effectiveness is reduced at pH values above pH 7.
Corrosion: Lead and Copper.
Low pH tends to make water more corrosive. A basic treatment technique to control lead and copper corrosion is to increase the pH.
Coagulation of Turbidity
Alum, the most popular coagulant if very sensitive to pH. Alum works best at a pH range of

63. pH Adjusters Raise pH Lower pH Soda ash X Caustic soda Lime
Sodium bicarbonate
Carbon dioxide
Sulfuric acid

64. Taste 4 tastes Sweet Salty Bitter Sour 4 taste sensations hot cool
astringent
acrid

65. ODOR
Treated or finished water is diluted with odor free water until there is no perceptible odor. The dilution factor needed to achieve no odor is the ODOR THRESHOLD NUMBER. Odor free water is produced by treating tap water with activated carbon.

66. Causes of Bad Taste and Odor
Plankton: various species of algae, especially blue green algae
Decayed vegetation-Decaying leaves are especially important in the late summer, early fall.
Dissolved minerals/gasses: sulfates, chlorides, iron, etc.
Industrial chemicals: phenolic compounds are especially a problem in very small concentrations, VOC, SOC,

67. MCL Inorganics Review Nitrate and Nitrite
MCL are: nitrate = 10 mg/L, nitrite = 1 mg/L, nitrate + nitrate = 10 mg/L
Blue baby syndrome or methemeglobinemia, results in loss of oxygen to the brain, with possible brain damage. Infants months most at risk.
Sources include fertilizer, animal manure, and septic tank leachate
Lead and Copper
Action Levels for lead and copper (When the Action Levels are exceeded, corrosion control is required), lead = mg/L, copper = 1.3 mg/L
The health effect of lead is damage to the nervous system and lowered intellectual development, especially in developing children.
The health effect of copper is minor, but can cause severe reaction in some individuals who are allergic to copper.
Lead and copper are regulated in a Treatment Technique which requires systems to take tap water samples at sites with lead pipes or copper pipes that have lead solder and/or are served by lead service lines. The action level, which triggers water systems into taking treatment steps if exceeded in more than 10% of tap water samples, for copper is 1.3 mg/L, and for lead is 0.015mg/L.
Fluoride
Fluoride MCL = 4 mg/L
Causes mottling of teeth and may cause bone deformation or fluorosis
Fluoride is a naturally occurring mineral that is normally present in groundwater.

68. MCL IOC and SOC SOCs IOCs
Certain inorganic chemicals can be toxic when found in drinking water.
Health effects include nervous system damage and cancer.
Some of the regulated IOCs:
arsenic, antimony, asbestos, barium, beryllium, cadmium, chromium, copper, cyanide, fluoride 4 mg/L,
lead regulated by action levels as part of the lead/copper rule
mercury
nitrate, nitrite 10, 1 mg/L (nitrate + nitrite must not exceed 10)
selenium
Thallium
SOCs
MCL, Health Effects, Sources, Sampling
Synthetic Organic Chemicals make up most of the regulated contaminants in drinking water! These chemicals are typically carcinogens. Examples of SOCs include
Pesticides like 2-4,D, methoxychlor, chlordane, di-methly bromide, dioxin
Solvents like TCE, carbon tetrachloride, benzene
Industrial chemicals like styrene, PCBs

69. MCLs DPB, Radionuclides, VOC
THMs and other Disinfection By-Products (DBPs)
Tri Halo Methane, or THM is the original regulated disinfection by-product. Most familiar is chloroform. THM MCL = 0.1 mg/L Considered a carcinogen
THMs form as the result of chlorine reacting with organic material in water, especially humus-like substances.
Sampling required for chlorinated systems greater than 10,000 pop., once each quarter. A running average is calculated.
Halogenated Acetic Acid, or HAA6 is an important new disinfection by-product
MCLs for disinfectants:
free chlorine 4 mg/L
chloramine 4 mg/L
chlorine dioxide mg/L
ozone
Radionuclides
Radionuclides emit alpha, beta and gamma radiation that can result in an increased risk of cancer from exposure. Contamination of water is the result of natural radioactive minerals in geologic strata.
VOCs
Volative Organic Compounds that are readily lost from water if it is exposed to air. They are a problem in groundwater not surface water. VOCs are chemicals used as solvents, cleaning agents, and gasoline additives
VOCs are suspected carcinogens; examples are the gasoline additives called BTEX
benzene
toluene
ethylbenzene
xylene
MTBE is a new concern in drinking water!

70. MCL Microbiological & Turbidity
Coliform Bacteria and Turbidity
Coliform bacteria are generally harmless indicator bacteria. They indicate possible fecal contamination and the potential for waterborne pathogens to be present.
No more than 5.0% samples total coliform‑positive in a month.
(For water systems that collect fewer than 40 routine samples per month, no more than one sample can be total coliform‑positive).
Every sample that has total coliforms must be analyzed for fecal coliforms.
There cannot be any fecal coliforms.
Fecal coliform and E. coli are bacteria whose presence indicates that the water may be
contaminated with human animal wastes. Microbes in these wastes can cause diarrhea,
cramps, nausea, headaches, or other symptoms.
Turbidity does not have a health effect. Turbidity is regulated for the following reasons:
it may interfere with the disinfection process
it may hide or protect microorganisms from the action of disinfectants
At no time can turbidity (cloudiness of water) go above 5 nephelolometric
turbidity units (NTU); systems that filter must ensure that the turbidity go no higher than 1
NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples
in any month.

72. Breakpoint Chlorination
Zone I: Chlorine is destroyed by reducing agents such as iron, manganese, clay and silt. Chlorine reduced to chloride
Zone II: Chlorine comes into contact with organics and ammonia. Chloroorganics and chloramines are formed.
Zone III: Chloroorganics and chloramines are partially destroyed. Chloramines are broken down and converted to nitrogen gas which leaves the system
Zone IV: Breakpoint. Beyond this point, free available residual is formed. Some chloroorganics still remain as combined residual.
Chlorine demand is difference between applied chlorine and the free chlorine residual at any two points on the breakpoint curve.

73. The objectives for this week to become familiar with basic characteristics of drinking water quality has been met
Strongly Agree
Agree
Disagree
Strongly Disagree