Water Treatment 2

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Water Treatment 2
2014-12-07 22:49:20
Water treatment

water treatment 2
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  1. What are the two sources of waste streams in conventional treatment?
    Sedimentation sludge filtration waste washwater
  2. Of these two which is generally of the greater quantity?

    Sedimentation Sludge
    Filtration wast wahswater
    Wast wash water
  3. Which is generally of the greater solids density?

    Filtration wash water or sedimentation sludge?
    Sedimentation sludge
  4. What is usually the first facility used to process waste wash water?
    Wash water recovery Basins
  5. What two functions are performed in a typical washwater recovery basin?
    Flow Equalization sedimentation
  6. What process uses gravity to separate suspended solids from water?
  7. Stores high waste stream flows before slowly returning them to the main plant flow stream?
    Flow Equalization
  8. What is the maximum rate of return permitted for recycled waste streams into the main flow stream?
    10 %
  9. What is the maximum turbidity allowed foe recycled waste streams?
    2 TUs.....Turbidity Units
  10. What process is typically used as the final dewatering step in sludge processing?
    Sludge drying beds
  11. What type of chemical will form DBPs during normal treatment operations?
  12. Which of the following will cause the sludge produced from the Sedimentation process to increase in percent solids?
    Decreasing the frequency of sludge removal
  13. Where is the most likely first destination for waste washwater leaving the Filtration process?
    Washwater recovery basins
  14. The underflow from Washwater Recovery is normally piped to the
    Sludge thickening process
  15. The maximum percentage of the total plant flow that can be from recycled waste streams is
    10 %
  16. Which of the following processes produce a waste stream?
  17. The waste stream generated by the Sedimentation process is known as
  18. The relatively clear water that forms the effluent stream from a Sedimentation process is called the
  19. Washwater recovery basins serve two key functions.  These are
    Flow equalization and solds removal
  20. he approximate percentage of solids in Sedimentation process sludge is
    1 %
  21. Which of the following processes produce waste streams?
  22. Moderate or High TOC levels in raw water may require which of the following treatment processes?
    Enhanced coagulation
  23. How many carbon atoms are present in the molecules of HAAs?
  24. Which of the following disinfectants will generally produce the lowest overall levels of currently regulated DBPs?
  25. Which of the following will react with chemical disinfectants during drinking water disinfection?
    • Non-pathogenic microorganism
    • Natural organic matter
    • Algae
    • Pathogens
  26. Which of the following processes could be effective in the reduction of THM precursors?
    • Aeration
    • Advanced membrane processes
    • Activated carbon filtration
  27. What will be the likely impact of elevated raw water Bromide levels on DBP formation?
    Higher levels of TTHMs, HAAs, and Bromate
  28. DBPs sometimes found as trace impurities in commercially available sodium hypochlorite solutions include
    • Chlorate
    • Chlorite
    • Bromat
  29. Which of the following would be considered Natural organic matter?
    • Algae
    • Debris from plants and animals
    • from the watershed
    • Live microorganisms
    • Dead pathogens
  30. What is the MCL for TTHMs?
    80 ug/L
  31. The overall level of precursor material for THM production is measured in the laboratory as
    Total organic carbon
  32. How many carbon atoms are present in the molecules of HAAs?
  33. The main public health risk attributed to TTHMs and HAAs is
  34. Which of the following would be considered as a moderate level of TOC?
    3 mg/L
  35. disinfectants is likely to form the highest level of THMs?
    Free chlorine
  36. Approximately what percentage of the water captured in the waste streams of Conventional Treatment plants is recovered and recycled through the main treatment plant?
    99 %
  37. The approximate percentage of solids in Sedimentation process sludge is
    1 %
  38. The waste stream generated by the Sedimentation process is known as
  39. Which of the following is likely to cause a deterioration in the performance of the Filtration process?
    Hydraulic surging
    Flow equalization
    Supplemental scoural
    Hydraulic surging
  40. Chlorine is applied at a dosage rate of 2.5 mg/L.  After a reaction time of over 4 hours in the clearwells, the chlorine residual is 1.5 mg/L.  What is the chlorine demand?
    1.0 mg/L
  41. A 20 MGD conventional plant must achieve a CT of 60 mg/L*minutes for disinfection.  If its disinfection process has a t10/T ratio of 0.80 and a maximum theoretical detention time of 60 minutes, at what minimum disinfectant residual must they operate?
    1.25 mg/L
  42. A clearwell is 120 feet in diameter and has a water level of 24 feet.  What is the theoretical detention time in this tank if the t10 is 100 minutes, and the t10/T ratio is 0.65?
    154 minutes
  43. When ozone gas is processed through an ozone destruction unit, the outlet gas will contain a high concentration of
  44. Ozone is produced by applying electrical energy to a gas stream that contains
  45. Disinfectants that are also capable of improving coagulation, oxidizing iron and manganese, and producing other treatment benefits include
    a. Free chlorine
    b. Ozone
    c. Chlorine dioxide
    d. All of the above
    e. None of the above
    d. All of the above
  46. the following shows the correct ranking of disinfectant effectiveness (from best to poorest)?
    Ozone, chlorine dioxide, free chlorine, chloramines
  47. The drinking water disinfectant that is the triatomic form of oxygen is
  48. When used alone, sodium hypochlorite and calcium hypochlorite will produce which of the following disinfectants in drinking water
    Free chlorine
  49. Disadvantages to the use of chlorine dioxide include
    increased levels of the DBP chloriteFew current users in the USAVery little persistence of a disinfectant residualOccasional customer complaints of water odor
  50. Chlorine symbol
  51. Hypochlorous Acid
    HOCL  or HCLO
  52. Hypochlorite ion
  53. MonoChloramine
  54. NCl3
  55. Break point Curve
    The y axis is total chloramine residual +chlorine residual combined
  56. 1mg/l sodium Thiosulfate neutralizes
    1mg/L Cl2

    Combined chlorine reacts as well

    no residual after reaction
  57. hydrogen sulfide
    sym and where found

    found in deep lakes and wells
  58. Nitrite sym

    Nitrate is NO3-
  59. What chemical is added to water quality samples for dechlorination
    Sodium thosulfate
  60. What common metals found in many ground water sources will react with free chlorine?
    Iron and Manganese
  61. What odorous gas found in many ground water sources will react quickly with free chlorine?
    Hydrogen sulfide
  62. What chemicals is combined with free chlorine to form chloramines
  63. What are the three chloramine molecules
    • Monnochloramine
    • dichloramine
    • trichloramine
  64. what is the most desirable chloramine form in drinking water?
  65. In what form is the total chlorine residual before the final part of the breakpoint curve?
    • Combined 
    • Free chlorine
  66. What will be the result of adding additional free chlorine to already-formed chloramines?
    Chloramine destruction
  67. What are the nitrogen-containing products of chloramine destruction?
    Nitrogen gas and Nitrate
  68. Forms of chlorine demand
    inorganics; Iron,Manganese,Sulfide


  69. What is the term for the low spot on the chlorine breakpoint curve where no additional chlorine demand exists?
  70. which of the three forms of chloramines is the most odorous and the most dominant near the breakpoint?
  71. In what form is the total chlorine residual to the right of the breakpoint?
    Combined Free
  72. what is the term for changing free ammonia into into nitrate?
  73. If there is no residual is detected what can be done to satisfy requirments
    HPc test Hetrotrophic plate count <500 cfu
  74. SWTR Disinfectants
    • Free chlorine 
    • chloramines
    • chlorine dioxide
    • Ozone
  75. Which form of chlorine residual provides the greatest level of disinfection?

  76. Which form of chlorine residual yields the highest level of THMs/HAAs?

    combined of free?
  77. Free
  78. What is the MRDL for chloramies?
    4 mg/L
  79. What is the ideal ratio of chlorine to ammonia
  80. Converting water with a free chlorine residual to chloraminated water would require the addition of
  81. What is the percentage of ammonia present in Anhydrous ammonia?
  82. Which of the following will be formed when adding free chlorine to monochloramines?
  83. The most effective way to stop nitrification in a distribution system is
    Breakpoint chlorination
  84. What is the optimum ratio of chlorine to ammonia-nitrogen for the production of chloramines in a water distribution system?
  85. In Water Quality, what does MRDL stand for?
    None of the above
  86. A total chlorine residual measurement has been made.  How many points on the chlorine breakpoint curve might have this same level of total chlorine residual?
  87. Which of the following is a form of free chlorine demand?
    a.  Iron
    b.  Chloramines
    c.  Ammoniad.  Hydrogen Sulfide
    e.  All of the above
    All of the above
  88. Which of the following is a metal commonly found in groundwater that exhibits a significant chlorine demand?
  89. In addition to the growth of AOBs and NOBs in a water supply that is experiencing nitrification, what else is likely to occur?
    Growth of other heterotrophic bacteria
  90. If sufficient free chlorine is added to exceed the chlorine demand of a water source, what form of chlorine residual will be present?
  91. hat is the initial chemical that serves as the food supply for microorganisms involved in nitrification?
  92. What will be the chlorine to ammonia ratio when a chloraminated water is blended with a water with a free chlorine residual?
    Cannot be determined without further information
  93. Which of the following is an intended purpose of secondary disinfection?
    Limiting the growth of microorganisms in the distribution system
  94. When operating a distribution system with chloramines, the ideal ratio of free chlorine to free ammonia is
  95. The disinfectant that produces the most persistent residual is
  96. What is the MRDL for Chloramines?
    4 mg/L
  97. One of the main reasons that a distribution system is required to have a detectable residual disinfectant is to
    Protect the water supply from contamination
  98. What is the Primary MCL for Floride?
  99. Risk of excess floride?
    bone dissease
  100. What environmental factor is the basis for Floride secondary MCL of 2mg/l
    The Average annual Maximum daily air temp
  101. Sodium floride name and %
    NaF 45..25%

    97%-98% purity
  102. Sodium Florosilicate
    • Na2SiF6
    • 60.75% Fluoride
    • solid chemical 
    • least expensive
    • Saturation lvl varies with temp 
  103. Fluorosilicic Acid Chracteristics
    • H2SiF6
    • comes dissolved in water
    • EXTREMELY corrosive Low pH Liquid
    • 79.2%
    • 20-30% because water is the major impurity
  104. What chem are used to add fluoride to drinking water?
    • Fluorosilicic Acid
    • Sodium Fluoride
    • Sodium fluorocilicate
  105. What chem has the highest % Fluoride
    Fluorocilic Acid 79.2
  106. How cant excess fluoride be removed?
    Advanced treatment like ion exchange or membrane filtration
  107. Density =?
    D= weight / Volume
  108. The main impurity found in fluorosilicic acid is
  109. What concern is the basis for the secondary MCL for fluoride?
    Dental fluorosis
  110. Which of the following chemicals can be added to drinking water using a saturator?

    Fluorosilicic acid
    Anhydrous ammonia
     Sodium fluoride
    Sodium fluoride
  111. To determine the proper amount of fluoride to be added to drinking water, we must consider the
    • Percent fluoride of the chemical
    • Average annual daily air temperature
    • Amount of water being treated
    • Natural level of fluoride
  112. In which particle size category would we place fluoride?
  113. Which of the following elements is most likely to exist in water as an anion?

  114. considered in the establishment of an optimum fluoride level for drinking water?
    Average annual daily air temperature
  115. What is the most common means to feed a liquid chemical solution into drinking water supplies?
     Positive displacement pumps
  116. What is the most common and cost effective means to reduce natural fluoride levels in drinking water?
    Blending with lower fluoride sources
  117. A gravimetric chemical feeder determines the amount of chemical being applied by measuring its 
  118. Which of the following chemicals has the highest percentage of fluoride?
    Fluorosilicic acid
  119. Fluoridation chemicals have a known percent fluoride and a specified percent
  120. The purpose of fluoride addition to drinking water is to improve the
    Dental health of children
  121. lending is being used to control arsenic levels.  The first source has a flow rate of 1.0 MGD and an arsenic level of 15 ppb.  The second source has a flow rte of 1.2 MGD and an arsenic level of 6 ppb.  What is the blended arsenic level in ppb?
  122. A______is the substance in greatest abundance in a solution.

    A________solute is any other substance dissolved withing the _______
    • Solvent
    • Solute
  123. Physical removal of particles from materials it contacts
    Chemical removal of particles from materials
    • Erosion
    • Corrosion
  124. What is Saturation
    The maximum concentration of a solute that can be dissolved within a solution.
  125. Saturation levels depend on
    • Identity of the solutes
    • Temperature
    • pH
    • Many other factors
  126. Corrosion =
    Loss of mass
  127. Deposition
    • The migration of particles within the water to the wall of the container also known as 
    • Scale formation 
    • Gain of mass
  128. The treatment process used to control corrosion and /or deposition
  129. Galvanic corrosion is caused by
    Dissimilar metals that are electrically connected
  130. combating Galvanic corrosion
    • Interrupt the circuit
    • Protective coatings
    • Insulating Flange sets
  131. What effect will increasing water temperature have on corrosion?
  132. Which form of corrosion is more likely due to corrosive water?
    Uniform corrosion or Localized corrosion
    Uniform corrosion
  133. What is the most common means of estimating the corrosion/deposition tendency of water?
    Langlier index
  134. What is the most common means of directly measuring the corrosion/deposition tendency of water?
    Coupon Testing
  135. The langlier index for a water sample is calculated to be +.35 will this water tend to be corroding or depositing
    positive index Depositing
  136. The addition of acides will _____alkalinity
    Addition of basses will _______alkalinity
    • Decrease 
    • increase
  137. Raising the pH will cause _______ (mostly calcium carbonate) to leave the water and coat the container.
  138. _________are used for corrosion control
    Phosphate compounds
  139. What is the term for a chemical that ties up other chemicals in the water preventing them from paticipating in reactions including corrosion
    Sequestering or chelating agent
  140. Why are Fe/Mn problems more common in ground water?
    low Dissolved Oxygen
  141. What zone in a deep lake is most likely to have dissolved iron and manganese?
  142. Iron and Manganese secondary standards
    • Iron-.3 mg/l
    • Manganese - .05 mg/l
  143. What is the most common means of converting Fe/Mn from dissolved particles into suspended ones?
  144. What is the most common means of removing suspended Fe/Mn particles?
  145. What is a common filter medium for Fe/Mn removal?
    Manganese Greensand
  146. An insulated flange set is a mechanical device intended to prevent
    Galvanic corrosion
  147. Insoluble precipitates of Iron and Manganese can be removed from water by
    Conventional filtration
  148. Particles of manganese in drinking water will cause turbidity if they are
  149. Corrosion that is caused by electrochemistry between two different metals is known as
    Galvanic corrosion
  150. The process by which particles of matter are physically removed by water is known as
  151. Raising the pH of drinking water is most likely to cause
  152. A substance dissolved within a homogeneous solution of drinking water is known as a
  153. All of the above
  154. hat will be the result of adding free chlorine to water that contains dissolved iron and manganese?
    The formation of insoluble precipitates
  155. The most common means of assessing the stability of water is the
    Langlier Index
  156. Common acids used in water treatment include
    Carbon dioxide
  157. Water that has no tendency to corrode or to deposit is
    None of the above
    None of the above
  158. The saturation level of a solute in a homogeneous mixture is dependent upon
    • The identity of the solvent
    • The identity of the solute
    • Temperature
    • pH
  159. Particles of iron in drinking water will be dissolved in size if the water is
  160. It has been determined that a drinking water supply is slightly corrosive.  Which of the following chemicals is most likely to be used to resolve this situation?
    Chlorine dioxide
    Carbon dioxide
    Sulfuric acid 
    Caustic soda
    Ferric chloride
    Caustic soda
  161. The dominant substance in a homogeneous mixture is called a
  162. What is the term for multivalent cations in the water
  163. Are the particles that cause hardness in water

    suspended colloidal or dissolved
  164. Types of hardness
    Carbonate : Temporary

    Non-carbonate: Permanent
  165. Carbonate Hardness is
    Calcium and magnesium in combinations with two of the alkalinity anions

    Carbonat and Bicorbonate
  166. Why is Carbonate hardness known as temporary hardness
    it leaves the water upon heating 
  167. A 25 MGD treatment plant using lime/soda ash softening reduces the 280 mg/L total hardness to 40 mg/L total hardness.  How many pounds of hardness are removed each day at this facility?
  168. The process that is most commonly employed to return lime softened water to a near-neutral pH is known as
  169. In drinking water quality, multivalent cations are responsible for
  170. An alternative unit of hardness measurement to milligrams per liter is
     Grains per gallon
  171. A natural resin often used in ion exchange softening is
  172. In general, about how much total hardness is removed during conventional treatment?
  173. When added to water, which of the following substances would raise the pH?
  174. Which of the following is a concern posed by hardness in drinking water?
    Deposits of hardness are difficult to remove
    Formation of films on dishes and porcelain fixtures
    Higher consumption of soap for normal cleaning
    Formation of scale inside pipes 
    All of the above
    All of the above
  175. How will the surface charge on a resin compare to the surface charge on ions to be removed from the water?
    They will be opposites
  176. The conversion of a dissolved particle into a suspended particle is known as
  177. The metallic ions that contribute hardness to the water would fall into which of the following particle size categories?
  178. In contrast with conventional treatment, the amount of sludge generated by a lime softening plant is
     Significantly greater
  179. Which of the following is the smallest particle that exhibits all the properties and characteristics of a compound?
  180. The high pH and corrosiveness of water treated by lime softening are often alleviated by
    Split stream treatment
  181. In which particle size range would ions be classified?
  182. Compared to the number of cationic charges in a water sample, how many anionic charges must be present?
    Significantly fewer
  183. Ozone injection through diffusers is an example of which form of aeration?
    Gas into water
  184. Packed tower aeration is an example of which form of aeration?
    Water into air
  185. What feature of membranes determines the size of particles that will be removed?
    Pore size
  186. The name for water entering a membrane process that does not become product water
  187. Term for the water that becomes product in a membrane treatment process
  188. Membrane process that does not require differential water pressure?
    Electrodialysis or Electrodialysis Reversal
  189. Membrane process produces water that is similar in quality to that of a conventional treatment plant?
  190. Name the type of membrane material most commonly used in micro filtration and ultrafiltation
    Hollow fiber
  191. Membrane process that is capable of removing all dissolved salts from sea water
    Reverse osmosis
  192. Which of the membrane processes produces the largest amount of waste?
    Reverse Osmosis
  193. Approx operating pressure of a reverse osmosis process?
  194. Membrane process that operates at lowest transmembrane perssure
  195. A mixture of suspended particles in water is known as a
  196. What laboratory analysis is used to detect both natural and synthetic organic matter in the laboratory
  197. the following substances will exhibit an earthy/musty odor in water?
  198. In drinking water treatment, electrodialysis is an example of
    Membrane treatment
  199. Humic and fulvic acids are components of
  200. Which of the following processes will use hollow fiber membranes?
  201. A common means of transferring ozone gas into water is the
    Fine bubble diffuser
  202. When two GAC filters are operated in series, the second filter is known as the
     Lag unit
  203. In activated carbon filtration, the measurement of detention time in the process is called the
     Empty bed contact time