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CEE 370 |
Fall 2010 |
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1.
Do
Problem 10-4 in the D&M text
The following minearl analysis was reported for Michigan State Well water. Determine the following in units of mg/L as CaCO3
a. total hardness,
b. carbonate hardness and
c. noncarbonate hardness
|
Mineral |
Conc (mg/L) |
Mineral |
Conc (mg/L) |
|
Fluoride |
1.1 |
Silica (as SiO2) |
13.4 |
|
Chloride |
4.0 |
Bicarbonate |
318.0 |
|
Nitrate |
0.0 |
Sulfate |
0.5 |
|
Sodium |
14.0 |
Iron |
0.5 |
|
Potassium |
1.6 |
Manganese |
0.07 |
|
Calcium |
96.8 |
Zinc |
0.27 |
|
Magnesium |
30.4 |
Barium |
0.2 |
2.
Do
Problem 10-6 in the D&M text.
Two parallel flocculation basins are to be used to treat a water flow of 0.150 m3/s. If the design detention time is 20 min, what is the volume of each tank?
3.
Do
Problem 10-8 in the D&M text.
Assuming a conservative value for an overflow rate, determine the suface area ( in m2) of each of two sedimentation tanks that together must handle a flow of 0.05162 m3/s of lime softening floc. Use an overflow rate of 57 m3/day/m2.
4.
Do
Problem 10-12 in the D&M text.
The water flow meter at
the Westwood water plant is malfunctioning.
The plant superintendent tells you the four dual-media filters (each
5.00 m x 10.0 m) are loaded at a velocity of 280 m/day. What is the flow rate through the filters (in
m3/s)?
5.
Do
Problem 11-2 in the D&M text.
If the terminal settling velocity of a particle falling in aquiescent water having a temperature of 15°C is 0.0950 cm/s, what is its diameter? Assume a particle density of 2.05 g/cm3 and a density of water equal to 1000 kg/m3. Assume Stokes’ law applies.
6.
Microbial
Growth Problem (not in book)
You’re operating a batch reactor. At the start (time =0) you have 0.85 mg/L of biomass. After two full weeks of operation you find that the biomass concentration is 286 mg/L.
a. What is the specific growth rate assuming simple exponential growth throughout?
b. Is the value you calculated in part “a” equal to the mmax ? Why or why not? Explain.
7.
Do
Problem 11-20 in the D&M text.
The 500- bed Lotta Hart Hospital has a small activated sludge plant to treat its wastewater. The average daily hospital discharge is 1200 L/day per bed, and the average soluble BOD5 after primary settling is 500 mg/L. the aeration tank has effective liquid dimensions of 10.0 m wide x 10.0 m long x 4.5 m deep. The plant operating parameters are as follows: MLVSS = 2000 mg/L, MLSS = 1.2 x MLVSS, and return sludge concentration = 12,000 mg/L (VSS). Determine:
a. Aeration Period in hrs
b. F/M ratio
8.
Do
Problem 11-23 in the D&M text.
Using the following assumptions, determine:
a. the solids retention time (days), and the
b. cell wastage flow rate
for the Lotta Hart Hospital problem above.
Assumptions:
|
Suspended solids in effluent = 30 mg/L |
Bacterial decay rate = 0.060 day-1 |
|
Wastage is from the return sludge line |
Inert fraction of suspended solids = 66.67% |
|
Yield coefficient = 0.60 |
Allowable BOD in effluent = 30.0 mg/L |
Assigned: 1 Dec 10
Due: 8 Dec 10
Answer Page
Fill in the boxes with the correct answer.
Your Name: ____________________________________
You will only get credit for a problem if you (1) fill in the box with the correct answer, (2) your answer is legible, and (3) you include attach page(s) with calculations backing up your answer, when requested for the problem.
Problem #
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1 |
a. |
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mg/L as CaCO3 |
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b. |
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mg/L as CaCO3 |
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c. |
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mg/L as CaCO3 |
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2 |
|
m3 |
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3 |
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m2 |
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4 |
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m3/s |
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5 |
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cm/s |
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6 |
a. |
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hr-1 |
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b. |
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7 |
a. |
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hours |
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b. |
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day-1 |
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8 |
a. |
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days |
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b. |
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L/day |