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Unformatted text preview: CEE 3104 (Marr) Final Fall 2005 1) You receive a 10-pound box of candy canes as a gift and because you don’t want to eat them
all and rot your teeth, you decide to dispose of them in a nearby creek. a) (10 points) First you dissolve the 4500 g of candy canes in 1000 L of water to make a
syrup-like solution. Model the candy canes as glucose, C6H1205 (MW = 180 g mol'l), and
calculate the theoretical oxygen demand (MW = 32 g mol'l) of the syrup in units of
mg L'l. Assume the following reaction applies for the degradation of glucose: C5H1206+602i>6C02+6H20
@Fmd glucose macaw/utter: = H500 - a M - M
C3” 7033315 "‘5 L (12(03)’ 0'025 a, 8‘“ @APPN $MCW’YM‘1‘} 'h’dfiermme 02 menu—0i 0014;, cf“: “0.015 mg): mg ”£9501 (3) CJYWEX‘i +0 W1. ThOD“ 0"5 ”45‘(%1?)('9%>‘ b) (10 points) Suppose you have an infinite su ply of candy cane syrup and pour it at a rate
of 0.10 L s'1 into a creek flowing at 2.00 m s’1 with an upstream ultimate BOD of 3.0 mg L]. You may assume that the theoretical oxygen demand calculated in part (a) is the
mixture’s ultimate BOD. What is the'ultimate BOD just downstream of the discharge point? (32‘: 0.! L75.
we ._.___.———> Qa‘ 2.00 g‘flogff at W5 :2000 ‘5 Lot r? 3
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Lu :3") '53 : QuL-u 'l" QL L:
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= new)
’— 2000 173 : [31m "$4 30f? CEE 3104 (Marr) Final Fall 2005 c) (18 points) Determine whether your candy cane syrup will threaten the wildlife
downstream. If the creek is flowing at a velocity of 0.10 m 5'], and the deoxygenation rate
coefficient is 0.1K) day’l, what is the minimum DO that will be reached downstream? The creek’s average depth is 2.0 m, and the saturation D0 is 9.0 mg L'l. Just downstream of
the discharge point, the D0 is 7.0 mg L'l. E Daz‘DostOa: Cl40’?'0 :2‘0 "34" 3‘! “"2. "z
2 ‘4 .. L, 3.6: 0.1)
O ' Hi"; :2 “(34373713 0.0”! Zlas/ l
b t s w 03.33 , (2.0 "wk 0.4+owI/a)
O o 0~””'0'Ll/‘l Q“ {at} (l (owl/oi (3.24 W‘s/b) > z 03‘"! 0‘ (0.7%!
: (ow/099.14 Wet) (-(aH/AXO-Wd) ” 4mm) )
®D° EMA/A) C 5 - (0. 44 4009.49 at)
l’ 2.0 ”94, C : 32.1%00 Mal, (03161-0,709) +— NUS "3", W Cot/mtg, W.SL1'f‘/40 has a VWV
Sta/Lam, 6% OWL 330 (VUSuS upsheam
valuL a? 7'0 "1%) W does mi' ”may union nCe. 4of7 CEE 3104 (Marr) Final Fall 2005 2) The major treatment processes of a wastewater plant are shown in the diagram below.
a) (8 points) Match each letter to the process name. screening discharge to landfill to solids to solids
treatment treatment
0 aeration basin E primary settling tank
5 disinfection contact basin 1) secondary settling tank A grit chamber
b) (4 points) What is the purpose of adding air to the aeration basin?
Pravda 02a: {or mafoorgaws m5 +9
425m org MM 6 W901 . c) (10 points) The primary settling tank is a rectangular plug flow reactor designed to settle
2000 m3 day'1 with an overflow rate of 32 m3 m'2 day'l. The tank is to be 2.4 m deep and 4.0 m wide. How long should it be? v0: 312'. “a TM: "5 W 1‘”? W4
0.: I, T
1000...; .l 1f" A. = L W
“" L/"l “Mi-ow - é: - 625.11%
V L D W ’ 14,07"
A a g _ 20003?
4 \I T W‘ =62.5m" L1l5‘é9m a 512 d) (6 points) What detention time would it have? v- Act-t 05M) __._ 0.0M “7(th 50m...) 9" E " ""5 ' 2000 “3/4 50f7 CEE 3104 (Marr) Final Fall 2005 3) (20 points) You use your leftover candy cane syrup as a tracer to examine soil properties in
your backyard. Based on observations of the rate of travel between two observation wells, you determine that the average linear flow velocity of the tracer in the aquifer is 1.0 m day'1
when the hydraulic gradient is 0.0005. The tracer has a retardation factor of 2.5. You test a
sample of the aquifer and find that its porosity is 0.20. Estimate the hydraulic conductivity of the aquifer.
R = 2 .5 Vf to "a
, ; 0.1
41‘ - 0.0005 7 alL.’
Find .4
0 Final VJ, R= fi’ ;> “34.0 mags): 2.5 "'4 V'e
(:9 Fwwl V
V : v'q = (:25 @001) = 0.5 ”/4 @ A'PPM Dmr'cv's [ml 47% K 4k v
Vsnv:;(4=-—/ 05%!
AL. AL : ..
2L 0.0005” " £1000 "4/4 1 4) (16 points) The Clean Water Act (CWA); Safe Drinking Water Act (SDWA); Resource
Conservation and Recovery Act (RCRA); Comprehensive Environmental Response;
Compensation, and Liability Act (CERCLA); and Clean Air Act (CAA) are five major pieces
of legislation that drive environmental engineering practices. Match each situation below to
the most relevant piece of legislation (use the acronym). You may use each option more than once or not at all. a) 09 W Cleanup of the trichloroethylene spill shown in the movie “A Civil Action” b) CW A Use of advanced treatment to remove excessive nutrients at a WWTP c) g M Installation of vapor recovery nozzles on gasoline pumps d) KCRA Storage, use, and disposal of hydrochloric acid in a chemistry laboratory 6of7 CEE 3104 (Marr) Final Fall 2005 5) While camping in the Shenandoah National Park, you build a campfire on the ground and
wish to calculate if its emissions will impact people at a neighboring downwind campsite.
The campfire has plume rise of 1.5 m and emits particulate matter (PM) at a rate of l"g s‘l.
The wind speed is 3.0 m s], and the stability class is D. a) (15 points) What is the PM concentration at the neighboring campsite, which is 300 m
directly downwind of your campfire? 08nd 5‘1,S} @ 0.3 km , D (’73:)? N“ C: 7r(2lm)(:!1m)(3"’5) ”P (O) 6"? (I, b) (4 points) How does this compare to the national standard for PMlo of 150 pg m'3? HJXHO‘" %3('9—¥3)2 4/3/8413 Mm, i‘MM double V g BAD c) (6 points) Which of the other criteria pollutants (03, CO, NOX, SOX, Pb) might the
campfire also produce? Justify your answer. CO, moan/b.0161} Wk (1950'?! Nox' watt Wmi comb “350-34 7of7 ...
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