finalfall04sol

finalfall04sol - CEE 3104(Marr Exam 3 Short answer...

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Unformatted text preview: CEE 3104 (Marr) Exam 3 Short answer questions 1) Someone spills several barrels of a light non-aqueous phase liquid onto the Drillfield, and it ends up contaminating the groundwater below. Name one way to remediate the subsurface pollution, and describe how the method works. am 79/1 - match“ «We es Vapm 6' k LIZ/W 20):: W1; flwm 59m. am, army/7m (0 1px;; W—CXfma‘gWa/Wm frag/#474 3 b/a/W aka/'0‘ *- mke advamz‘agz 0F mam/74,15,715 ' 79 day «we fire. "~ ’6, Wm bane... éurn er" 2) De me hardness in water. Why are we concerned about it? 5:27 5, Swm of Mt? VW C m yams W55 Causes 3%; m p/uméa’y 57 64/14 lead 7’” r9551”? Mp5, 5.49%; G Momma (FEW .af Malta} knit-r2?ch cafe ma/zps 1W»? (4/; Soap Cor/.7, 3) A flocculation basin is used to treat a water flow of 0.20 m3 s". If the design detention time is 20 minutes, what is the volume of the tank? all-3 9- M '61 Q a 10 m V= 961:4” MXO.ZW%)(%)=IZHO m3. 4) Pick any three of the six criteria air pollutants CO, N02, 03, 802, Pb, and PM, and describe the major sources that contribute to their emissions. 5 t PWN-Nts/mmd Wm ’01 above Sou/as; VOC 9mm valve/Les, {may}, W «19(0th (W5) 5 L- cod—97M power plant; Plenum/MN?) leaded gaso fma, W W mm raoUAchm Mm) ’ b ‘l P + ambWh‘m smote» fiwmmm 17M, wmalblmfln 01w , 20” I (3' V CEE 3104 (Marr) Exam 3 5) A city of 200,000 people disposes of 1.0 m3 s'1 of treated sewage that has an ultimate BOD of 28 mg L'1 and D0 of 1.8 mg L‘1 into a river. Upstream from the outfall, the river has a flowrate of 7 m3 s'l, ultimate BOD of 3.6 mg L'l, and D0 of 7.6 mg L'l. The saturation value of DO at this temperature is 8.5 mg L'l. The deoxygenation coefficient is 0.6 day'l, and the reaeration coefficient is 0.8 day". Downstream of the outfall, the river’s velocity is 0.4 m s". l (e a) What is the oxygen deficit and the ultimate BOD just downstream fi'om the outfall (just after mixing, before any reaction can occur)9 _ mm a, a was ,5 - 28 “a , WM It W91, F'VCV HM Dd (bl, Finding DOdMLM 62? 7V" M Mum? “dawns‘tm'm” par-4T7 Lv'r :- 3 (O W . 0' C?(D0r*051704w D0(3 7‘6 W94, ' wa(4 42d 3 0=QrLor+ QsLas' 0.: w ( més)(7'é W94)+U mgxl 8%) La ., QrLor'fasLoi' grid/5 Loot " b) What is the DO 16 km downstream? - /d _ r, -m v 34 O!” \7/ Dorm " +126 1“, 0W4 mm b? D0 517d = ‘6 W/V t: a... Was)— oflé A 3of6 CEE 3104 (Marr) Exam 3 6) Below is a schematic of two wells located in a flood plain. The water level (meters of head above mean sea level) within well A is 213 m and the water level within well B is 207 m. The applicable hydraulic conductivities in each geologic unit are Ksand_g,ave1 = 10'2 cm s'1 and Kclay = 10'6 cm s". 1000 meters (—> A 1441 2‘3” 13 “Bf 20.7 M Water table Sand and Gravel a) Calculate the Darcy velocity in the longitudinal direction (towards the river from A to B) for the sand and gravel aquifer in cm da ' . , .. r BID} 'hB 3 ‘0 Z m W148i) FM 50" ’f‘" amom=0'009 V: (0.0! macaw e M0693 ( [5‘1 if} b) If the porosity is 0.3, what is the average linear velocity of the water as it flows through the sand and gravel aquifer to the river? How long will it take for the water to travel 1000 m? 3’ ,%%i%l=173 6%” f: a: W045804 c) What is the volume flowrate in m3 day"1 if the cross sectional area of concern is ‘10 m x 50 m? &= M a: = (aw cwdfimxwmxwo.006M??? $7 4of5 '1'! CEE 3104 (Marr) Exam 3 7) A 500 MW power plant has a thermal efficiency of 30%, and the coal it uses has an energy content of 13,600 Btu lb'l. The coal has an ash content of 1% by mass, and all the ash in the coal is emitted as particulate matter (PM), with a ratio of 1:1, i.e. every 1 g of ash in the coal becomes 1 g of PM that is emitted. The power plant uses no pollution control equipment. a) What is the PM emission rate from the power plant in lb HI? I Haw WW1 aim/‘94? mmfi/ym g? cod 1‘5 b~"*.¢2¢££..d? O u) ' —- W 500 MM) w <— ‘9 Q” 7L: 7.2, {um/14w 6-4 7 (’9va Wk 0001 '5 W ,. O‘Z‘N‘Whr _r flf é QM CW WW: (3600?? [email protected] )‘3a’5/5 lb =aé—r'a 'a—ie" 4. ééXiOéw {lb M M. emu“ Wt gays U37? ;L{,2x l0 1:; 6 @WM GMWXMI, 3:. PM, fig m ow («my a“ b) Name one type of pollutant control device that could be used to reduce the PM emissions. Q1 0! arm, ‘9! Hex (Q elect {’0 9mm & pmup Martyr (3% P) 50f5 "Tl- ...
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This note was uploaded on 03/31/2008 for the course CEE 3104 taught by Professor Lcmarr during the Spring '07 term at Virginia Tech.

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finalfall04sol - CEE 3104(Marr Exam 3 Short answer...

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