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NSM Vol 2 Ch. 3
| Question | Answer |
|---|---|
| Why do some water treatment plants avoid addressing iron, manganese, arsenic and disinfection byproducts in their treatment operations? | They meet regulations without treatment |
| Which source water is most likely to contain iron and manganese? | Wells and springs |
| ----- obtain energy for growth from the chemical reaction that spontaneously occurs between iron and manganese nd dissolved oxygen. | iron bacteria |
| What color on the inside walls of filters and the filter media indicates the presence of both iron and manganese if the raw water is prechlorinated? | Brownish-black |
| Which errors often cause inaccurate iron and manganese test results? | Incorrect sampling and laboratory procedures |
| What indicates that water produced by a well is being drawn from more than one aquifer? | Dissolved oxygen |
| The concentration of a standard polyphosphate solution is 1 mg/mL. If 6 mL of the stock solution are added to a 1 L sample, what is the polyphosphate does in pounds per million gallons? | 50 lb/Mgal |
| Determine the chemical feeder setting in pounds of polyphosphate per day if 0.62 million gallons per day is treated with a dose of 6 mg/L. | 31 lb/day |
| What should never be fed ahead of polyphosphate used to control iron and manganese? | Chlorine |
| What indicates that it is time to regenerate an ion exchange unit that is treating iron and manganese? | Iron and manganese start to appear in the treated water. |
| What is the purpose of baffles in a reaction basin in an aeration process? | To prevent short circuiting |
| A reaction basin 14 ft in diameter and 4 ft deep treats a flow of 240,000 gallons per day. What is the average detention time in minutes? | 28 min |
| What determines the rate of oxidation of iron and manganese with chlorine? | Chlorine residual |
| In continuously regenerated manganese greensand processes, what is the chlorine dosage? | The same as the iron concentration |
| Calculate the potassium permanganate dose in milligrams per liter for well water with 0.3 mg/L iron concentration and a manganese concentration of 0.8 mg/L. | 1.66 mg/L |
| Which water supplies are most likely to use electromedia iron and manganese systems? | Groundwater supplies at individual well sites. |
| How can a distribution system be cleared of iron bacteria? | Develop a flushing program |
| What is the most common source of arsenic in water? | Natural leaching from soils |
| Where should emergency eye wash stations, deluge showers, and floor washdown equipment be located in an arsenic removal plant? | In the chemical storage and supply building |
| Why might some water systems consider using an alternative source rather than implementing treatment processes for arsenic? | Most economical solution |
| What are the common stages of operation for an ion exchange unit? | Service, backwish, brine and rinse |
| What kind of process is activated alumina? | Adsorption |
| Well 1 delivers 60 gpm with an arsenic concentration of 0.014 mg/L. Well 2 delivers 480 gpm with an arsenic concentration of 0.003 mg/L. What is the blended arsenic concentration in mg/L if the flows from these two wells are blended together? | .004 mg/L |
| What wastestream from an arsenic removal plant may be hazardous waste? | Brine |
| What are compliance monitoring samples? | Mandated samples that must be analyzed by an approved laboratory and reported to the regulatory agency. |
| what are routine reports for arsenic removal treatment plants? | Monthly summary reports required to be submitted to the regulatory agency. |
| When the oxidants use to disinfect water come into contact with----- and ----- materials already present in the water being disinfected, disinfection byproducts can form as a result of chemical reactions. | organic, inorganic |
| Why can systems using chlorine or chloramines temporarily increase residual disinfectant levels to address microbiological contamination problems and stay in compliance. | Compliance is based on running annual arithmetic averages |
| What are natural, organic compounds found in all surface and groundwaters that may react with halogens. | THM precursors |
| The higher the ----- the faster THMs will be produced | temperature |
| What are the number of samples and the schedule for routine monitoring sampling based on? | Source water type and population served |
| Calculate the quarterly TTHM average in mg/L for a treatment plant with the following four sample results: 0.07 mg/L, 0.08 mg/L, 0.12 mg/L and 0.05 mg/L | .08 mg/L |
| What can be removed before chlorine is added to control THMs | THM precursors |
| Why do THMs leave water that is standing uncovered? | THMs are volatile compounds |
| What type of distribution system monitoring must be provided by a utility before and after a disinfectant change? | Upgraded monitoring (more samples and tests) |
Created by:
sgaskell