CE 310 Sample Second Midterm Spring 20XX Closed Book/Closed Note Portion B.A. DeVantier Matching. (2 points each) Put the letter of the description on the right which best describes one of the terms on the left. No letter may be used more than once. _K Carbonaceous BOD _C Nitrogenous BOD A. Saturated soil region above GWT. B. Theoretical surface of peizometrically pooled water. _A Capillary fringe C. Water pollutant measurement of biologically oxidizeable organic nitrogen or ammonia. _J Vadose zone D. Sum of organic nitrogen and ammonia measured as N. _N Nonvolatile Dissolved E. in a water sample due to grit and soil particles. _G Volatile Suspended F. Detectable toxicity dose. _H Volatile Dissolved G. in a water sample due to bacterial cells. _E Nonvolatile Suspended H. in a water sample due to dissolved organic solvents. _B GWT I. Toxicity dose just below the threshold dose _O Aquifer _D TKN _I NOAEL _F LOAEL _L RfD _M HI J. Unsaturated soil region above the level of capillary rise of water. K. Water pollutant measurement of biologically oxidizeable organics with nitrification suppressed. L. Toxicity dose well below the threshold by a safety factor. M. Cumulative sum of toxicity dose ratios relative to established standards. N. in a water sample due to salts in solution. O. Underground body of water. Multiple Choice. (2 points each) Circle the letter of the phrase which best completes each sentence below. 1. The sun is related to trophic levels because A. it is a producer. B. it represents the highest trophic level. C. it drives all of the cycling of materials important to life. D. all life is destroyed as it nears the sun. 2. A chemical which inactivates ammonia is added in a standard five-day BOD test to A. add DO to be sure there is enough. B. block production of ammonia that is a product of aerobic microbial metabolism. C. suppress nitrification consumption of oxygen. D. kill bacteria in the sample.
3. A bioaccumulated (or bioconcentrated) substance moves A. from the lowest trophic levels to the highest in the food chain. B. downstream in a river ecosystem. C. from the largest organisms to the smallest in an ecosystem. D. from the highest trophic levels to the lowest in the food chain. 4. Deoxygenation in an oxygen sag curve is due to A. turbulent eddies in a river constantly bringing water to the air at the river s surface. B. chemicals from agricultural pesticide use in runoff to a river. C. a lack of oxygen on a river bottom. D. aerobic organisms consuming biodegradable organics discharged to the river. 5. The time of concentration of a watershed is A. the time it takes to remove a contaminant in a watershed to the DWEL. B. the focal point in time of storm precipitation intensity falling onto the watershed. C. the time it takes precipitation runoff to travel from the most remote watershed point. D. all of the cumulative runoff flowing out of a watershed area. 6. Oxygen sag occurs in a river due to an oxygen depleting discharge, because A. oxygen is added by aeration faster than it is depleted. B. no oxygen is added by reaeration. C. dissolved oxygen is depleted faster than aeration adds it. D. saturation dissolved oxygen decreases. 7. The worst case condition for oxygen sag with regard to temperature is high temperature, because A. deoxygenation rates decrease. B. reaeration rates increase. C. saturation dissolved oxygen is decreased. D. all of the above. 8. A water sample s ultimate BOD A. is equal to its nitrogenous BOD. B. is less than its five-day BOD. C. is greater than its five-day BOD. D. can be a negative value. 9. Producer organisms A. heat up the atmosphere. B. tend to convert matter from biotic form to abiotic forms. C. tend to convert matter from abiotic form to biotic forms. D. create dead ends in natural cycles. 10. E. coli are used as indicator organisms, because A. they have an indicative color. B. they are so rare that their presence indicates a problem. C. they exist in large numbers in the intestines of humans& might mean fecal contamination. D. they can cause terrible disease when present in undercooked meats.
CE 310 Sample Second Midterm Spring 20XX Open Book/Open Note Portion B.A. DeVantier Problem 1 The USEPA drinking water standard for arsenic is 10 ppb. Estimate the additional risk for females consuming water at this limit for a lifetime exposure of 75 years, and translate that risk into the number of additional cancers per million women.
Problem 2 (15 points) A lab technician is surprised by higher than usual BOD5 results for the effluent of a sewage treatment plant at a level of 26 mg/l. After some investigation the technician finds that the thermostat in the BOD incubator has malfunctioned, and the temperature of the test had been held at a higher level than the standard of 20 C. If the technician was expecting a BOD5 of 20 mg/l, and he knows that the first order BOD rate constant at 20 C is 0.23 day -1 for this water, use the first order BOD model and the temperature correction factor to estimate the temperature that the incubator had improperly held.
Problem 3 (20 points) A river flowing at 4 mi/day and 25 ft 3 /s receives a flow of 0.1 ft 3 /s leaking from a syrup storage tank at a factory next to the river. The ultimate BOD of the of the syrup is 3000 mg/l. The stream temperature of 25 C is not affected by the small flow of the leak nor is the dissolved oxygen level of the stream of 7 mg/l. What is the dissolved oxygen in the stream 6 miles downstream of the leaking flow if we know that the river before the leak point has an ultimate BOD of 1 mg/l and the deoxygenation rate constant is 0.3 day -1 and the reaeration rate constant is 0.25 day -1 at the river temperature?