| # | The term aeration is defined as bringing water into contact with | ozone. | methane. | carbon dioxide | air. | hydrogen sulfide. | 4
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| 1 | The main purpose of presedimentation is to what? | Increase the oxygen content of the water. | Increase the alkalinity of the water. | Decrease the oxygen content of the water. | Reduce the silt in the water. | Decrease the alkalinity of the water. | 4 |
| 2 | Microstraining is the treatment technique that is normally designed to remove _____________ from the water. | Iron and maganese | fish, logs and other large debris | algae and coarse suspended solids | dissovled solids and other micro suspended solids | all of the above | 3 |
| 3 | Hydrogen sulfide in water may be effectively controlled by which of the following treatment processes? | filtration and sedimentation | sterilization | floridation | filtration only | aeration | 5 |
| 4 | Water may be aerated by several methods, almost all of which invovle | covering the storage facilities. | decreasing the pressure. | increasing the preasure. | exposing a large surface area to the atmoshpere. | reducing its temperature. | 4 |
| 5 | One function of aeration is the removal of __________ prior to the lime-soda ash softening process. | carbon dioxide | chlorine | inorganic material | iron and maganese | all of the above | 1 |
| 6 | The detention time usually required in a conventional straight flow sedimenttation basin is | 15 - 30 minutes. | 30 - 60 minutes. | 1 - 3 hours. | 2 - 6 hours. | 9 - 12 hours. | 4 |
| 7 | Sedimentation is improved by what? | Short circuiting across the basin. | Uniform, horizontal, low velocity across the basin. | A sludge blanket with a depth greater than 1.5 ft.. | By reducing the detention time in the basin. | By increasing the flow into the basin. | 2 |
| 8 | The most desirable place to feed activated carbon in a lime-soda ash softening plant is where? | With the lime feed system. | After the lime feed system. | In the clear well. | To the raw water at the earliest stage as possible. | Right after the chlorine feed line. | 4 |
| 9 | Filters in a water treatment process are primarily used for removing or reducingwhat? | Color. | Taste and odors. | turbidity. | carbon dioxide. | Pathogenic organisms. | 3 |
| 10 | How many inches of vertical rise per minute is the recommended rate of flow for filter wash water in a rapid sand filter? | 1 in. | 20 - 30 in. | 30 - 45 in | 5 - 15 in. | 75 in. | 2 |
| 11 | Rapid sand filters should be backwashed at least when? | The head loss is 6 ft. | The filter run exceeds 100 hours. | there is a sudden increase in effluent turbidity. | The effluent turbidity exceeds 1 NTU. | All of the above. | 5 |
| 12 | Air binding of a filter can be caused by | reduction of preasure resulting from operating under a negative head. | An increase in the temperature of the water during filtration. | the release of ozygen by algea collected within the filter. | All of the above. | | 4 |
| 13 | Disinfection is | killing all bacteria. | killing only protozoans. | killing pathogenic bacteria. | all of the above. | none of the above. | 3 |
| 14 | Chlorine gas is | lighter than air. | denser than air. | the same as air. | a odorless gas. | none of the above. | 2 |
| 15 | Which of the following is not used as a dechlorinating agent? | sulfur dioxide | potassium permaganate | sodium bisulfate | activated carbon | none of the above | 2 |
| 16 | Chloramines are formed by the addition of chlorine and | ammonia. | soda ash. | liquid no=itrogen. | sodium floride. | alum. | 1 |
| 17 | Taste and odors from phenolic compounds may be ________ by chlorination. | increased | decreased | removed | destroyed | none of the above | 1 |
| 18 | The most important use of chlorine in water treatment is it's use to what? | Aid in coagulation. | aid in filtration. | Remove algea. | Disinfect. | Aid in sedimentation. | 4 |
| 19 | Which of the following items MUST be replaced when connecting up a new chlorine cylinder? | Needle valve and seat. | Lead or fiber washer. | Preasure regulator. | Air and water regulators. | none of the above. | 2 |
| 20 | What is used to detect chlorine leaks? | 10 % solution of sodium hydroxide. | 10 % solution of ammonia hydroxide. | 10 % solution of calcium hydroxide. | 10 % solution of aluminum sulfate. | 10 % solution of EDTA and indicator. | 2 |
| 21 | Chlorine is very corrosive when it is mixed with what? | Alum. | Moisture. | Carbon. | Floride. | Hypochlorite. | 2 |
| 22 | Chlorine leaks in metal containers tend to do what? | Get larger. | Get smaller. | Stay the same size. | Seal themselves up. | Freeze over and prevent more leakage. | 1 |
| 23 | After all demands of the chlorine have been met, what is the term used for any remaing free chlorine? | potential | residual | differential | breakpoint | accounted for | 2 |
| 24 | The density of chlorine is about how many times greater than air? | 1/4 times | 1 1/2 times | 2 times | 2 1/2 times | 3 times | 4
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