Answers to More M&M Today's Questions
Wastewater Treatment, Water Treatment, Distribution, and Collection
How about some practice calculating pump capacities?
| Formula | SWD - Min Depth | (L)(W)(H) | Vol ÷ Time | gpm x 1440 | gpd ÷ 1,000,000 | gpm x 7.5 ÷ 60 | ||||
| L, ft | W, ft | SWD, ft | Min Depth, ft | Draw-down, ft | Volume, cf | Draw-down Time, min | Flow, gpm | Flow, gpd | Flow, MGD | Flow, cfs |
| 20 | 10 | 12 | 4 | 8 | 1,600 | 30 | 400 | 576,000 | 0.576 | 0.889 |
| 30 | 15 | 14 | 5 | 9 | 4,050 | 35 | 868 | 1,249,714 | 1.2497 | 1.93 |
| 50 | 25 | 16 | 6 | 10 | 12,500 | 40 | 2,344 | 3,375,000 | 3.375 | 5.21 |
| 80 | 40 | 18 | 7 | 11 | 35,200 | 45 | 5,867 | 8,448,000 | 8.448 | 13.04 |
| 100 | 50 | 20 | 8 | 12 | 60,000 | 50 | 9,000 | 12,960,000 | 12.96 | 20 |
How about some more practice calculating chlorine dosages, residuals, and demands in mg/L and lbs?
| Day | Flow | Chlorine | |||||
| MGD | Dose | Residual | Dose | Residual | Demand | ||
| LBS | mg/L | mg/L | LBS | mg/L | LBS | ||
| 1 | 0.61 | 8.38 | 0.50 | 1.65 | 2.54 | 1.15 | 5.84 |
| 2 | 0.59 | 7.43 | 0.50 | 1.51 | 2.46 | 1.01 | 4.97 |
| 3 | 0.58 | 7.67 | 0.50 | 1.59 | 2.42 | 1.09 | 5.25 |
| 4 | 0.54 | 6.93 | 0.50 | 1.54 | 2.25 | 1.04 | 4.68 |
| 5 | 0.80 | 9.02 | 0.50 | 1.35 | 3.34 | 0.85 | 5.68 |
| 6 | 0.82 | 9.92 | 0.50 | 1.45 | 3.42 | 0.95 | 6.50 |
| 7 | 0.53 | 6.48 | 0.50 | 1.47 | 2.21 | 0.97 | 4.27 |
| 8 | 0.52 | 6.56 | 0.50 | 1.51 | 2.17 | 1.01 | 4.39 |
| 9 | 0.60 | 7.83 | 0.50 | 1.56 | 2.50 | 1.06 | 5.33 |
| 10 | 0.51 | 6.76 | 0.50 | 1.59 | 2.13 | 1.09 | 4.63 |
| 11 | 0.57 | 6.75 | 0.50 | 1.42 | 2.38 | 0.92 | 4.37 |
| 12 | 0.75 | 8.48 | 0.50 | 1.36 | 3.13 | 0.86 | 5.35 |
| AVERAGE | 0.62 | 7.68 | 0.50 | 1.50 | 2.58 | 1.00 | 5.11 |
| MAXIMUM | 0.82 | 9.92 | 0.50 | 1.60 | 3.42 | 1.10 | 6.50 |
| MINIMUM | 0.51 | 6.48 | 0.50 | 1.40 | 2.13 | 0.90 | 4.27 |
How about some practice calculating chlorine dosages, residuals, and demands in mg/L and lbs?
| Day | Flow | Chlorine | |||||
| MGD | Dose | Residual | Dose | Residual | Demand | ||
| LBS | mg/L | mg/L | LBS | mg/L | LBS | ||
| 1 | 61 | 838 | 0.5 | 1.6 | 254 | 1.1 | 584 |
| 2 | 59 | 743 | 0.5 | 1.5 | 246 | 1.0 | 497 |
| 3 | 58 | 767 | 0.5 | 1.6 | 242 | 1.1 | 525 |
| 4 | 54 | 693 | 0.5 | 1.5 | 225 | 1.0 | 468 |
| 5 | 80 | 902 | 0.5 | 1.4 | 334 | 0.9 | 568 |
| 6 | 82 | 992 | 0.5 | 1.5 | 342 | 1.0 | 650 |
| 7 | 53 | 648 | 0.5 | 1.5 | 221 | 1.0 | 427 |
| 8 | 52 | 656 | 0.5 | 1.5 | 217 | 1.0 | 439 |
| 9 | 60 | 783 | 0.5 | 1.6 | 250 | 1.1 | 533 |
| 10 | 51 | 676 | 0.5 | 1.6 | 213 | 1.1 | 463 |
| 11 | 57 | 675 | 0.5 | 1.4 | 238 | 0.9 | 437 |
| 12 | 75 | 848 | 0.5 | 1.4 | 313 | 0.9 | 535 |
| AVERAGE | 62 | 768 | 0.5 | 1.5 | 258 | 1.0 | 511 |
| MAXIMUM | 82 | 992 | 0.5 | 1.6 | 342 | 1.1 | 650 |
| MINIMUM | 51 | 648 | 0.5 | 1.4 | 213 | 0.9 | 427 |
Chlorine ton cylinders at room temperature will deliver gas at a maximum rate of
150 lb cylinders Ton Containers
A. 10 pounds per day 100 pounds per day
B. 25 pounds per day 250 pounds per day
C. 40 pounds per day 450 pounds per day
D. 150 pounds per day 2000 pounds per day
The correct answer is C
Click on the thumbnail below for the answers for the chart of pump station math for cylindrical tanks.
Click on the thumbnail below for the answers for the chart of pump station math for rectangular tanks.
Click on the thumbnail below for the answers for the chart of pipe math.
Which of the following valves only permits flow to move in one direction?
A. Butterfly
B. Check
C. Gate
D. Plug
The correct answer is B
The specific gravity of a colloidal solid is very close to 1. This means that the colloid
A. Will float within an hour
B. Will settle within an hour
C. Won't settle or float
The correct answer is C
The specific gravity of settleable solid is
A. 1
B. Greater than 1
C. Less than 1
The correct answer is B
The specific gravity of a floatable solid is
A. 1
B. Greater than 1
C. Less than 1
The correct answer is C
The specific gravity of chlorine gas is
A. 1
B. Greater than 1
C. Less than 1
The correct answer is B
|
Matching |
|
|
1. Calcium |
A. C |
|
2. Carbon |
B. S |
|
3. Chlorine |
C. P |
|
4. Copper |
D. K |
|
5. Fluorine |
E. O |
|
6. Iron |
F. Na |
|
7. Hydrogen |
G. N |
|
8. Lead |
H. Mg |
|
9. Magnesium |
I. Ca |
|
10. Manganese |
J. Cl |
|
11. Nitrogen |
K. Cu |
|
12. Potassium |
L. Mn |
|
13. Sodium |
M. Fe |
|
14. Oxygen |
N. H |
|
15. Phosphorus |
O. Pb |
|
16. Sulfur |
P. Fl |
1. I
2. A
3. J
4. K
5. P
6. M
7. N
8. O
9. H
10. L
11. G
12. D
13. F
14. E
15. C
16. B
| Match | |||
| 1 | The units for pressure are | A | Divided by |
| 2 | Head is expressed in | B | 2.31 |
| 3 | Velocity is measured in | C | 0.434 psi |
| 4 | Units of flow | D | psi |
| 5 | Pressure times _______ = Head | E | fps |
| 6 | Head __________ 2.31 = Pressure | F | 1440 |
| 7 | 20 psi = | G | 694 gpm |
| 8 | 1 MGD = | H | cfs |
| 9 | A head loss of 7 feet = | I | 3 psi |
| J | Times | ||
| K | ft | ||
| L | 46.2 ft | ||
| M | Subtracted by | ||
1 = D
2 = K
3 = E
4= H
5 = B
6 = A
7 = L
8 = G
9 = I
Which of the following is correct?
A. A is the follower and B is the lantern ring
B. A is the lantern ring and B is a packing ring
C. A is a packing ring and B is the lantern ring
D. A is a packing ring and B is the follower
The correct answer is C. A is a packing ring and B is the lantern ring
pH measures
A. H+
B. OH-
C. O2
D. Phosphorus
The correct answer is A. H+ -- pH measures the hydrogen ion concentration
The formula for the volume of a rectangular tank is
A. (Length)(Width)
B. (0.785)(Diameter2)
C. (Length)(Width)(Height)
D. (0.785)(Diameter2)(Height)
The correct answer is C. (Length)(Width)(Height)
A is the formula for the area of a rectangle
B is the formula for the area of a circle
D is the formula for the volume of a cylinder
The formula for the volume of a cylindrical tank is
A. (Length)(Width)
B. (0.785)(Diameter2)
C. (Length)(Width)(Height)
D. (0.785)(Diameter2)(Height)
The correct answer is D. (0.785)(Diameter2)(Height)
A is the formula for the area of a rectangle
B is the formula for the area of a circle
C is the formula for the volume of a rectangle
How do you know that your pump is cavitating?
A. It doesn't sound right
B. It runs hot
C. It won't start
D. All of the above
The correct answer is A. It doesn't sound right.
A pump that's cavitating sounds like it's pumps rocks or gravel.
Given a tank measures 50 feet long, 25 feet wide, and 15 ft deep, calculate:
- Surface area in ft2
- Cross-sectional area in square feet
- Volume in cf
- Capacity in gallons
The correct answers are:
- Surface area in ft2
Surface area in ft2 = Length, ft x Width, ft = 50 ft x 25 ft = 1250 ft2
- Cross-sectional area in square feet
Cross-sectional area is square feet = Width, ft x Depth, ft = 25 ft x 15 ft = 375 square feet
- Volume in cf
Volume in cf = Length, ft x Width, ft x Depth, ft = 50 ft x 25 ft x 15 ft = 18,750 cf
- Capacity in gallons
Capacity in gallons = Volume in cf x 7.5 gal/cf = 18,750 cf x 7.5 gal/cf = 140,625 gal
A chlorine atom is composed of
A. Electrons
B. Neutrons
C. Protons
D. All of the above
The correct answer is D. All of the Above
Throttling the discharge valve on a centrifugal pump will the likely ______ temperature of the motor and ______ the temperature of the pump
A. Increase, increase
B. Increase, reduce
C. Reduce, increase
D. Reduce, reduce
The correct answer is C. Reduce, increase
A, B, and D are incorrect because throttling the discharge valve on a centrifugal pump will the likely reduce temperature of the motor and increase the temperature of the pump
The chemical symbol for chlorine gas is
A. Cl
B. Cl-
C. Cl2
D. HOCl
The correct answer is C. Cl2
A is incorrect because this is chemical symbol for chlorine not chlorine gas
B is incorrect because this is the chemical symbol for chloride
D is incorrect because this is the chemical formula for hypochlorite
Which of the following is the indicator used for pathogens?
A. Amoebic dysentery
B. E. coli
C. Salmonella typhosa
D. V. comma
The correct answer is B. E. coli
A is incorrect because this is a pathogen, not an indicator
C is incorrect because this is a pathogen (cholera), not an indicator
D is incorrect because this is a pathogen (typhoid), not an indicator
Pump suction and discharge pressures are usually measured in
A. gpm
B. kWh
C. mg/L
D. psi
The correct answer is D. psi
A is incorrect because this is a measure of flow
B is incorrect because this is a measure of energy used
C is incorrect because this is a measure of concentration
Which of the following is the correct formula for chlorine in water?
A. Cl2 + H2O → HOCl + HCl
B. NaOCl + H2O → HOCl + NaOH
C. Ca(OCl)2 + 2H2O → 2HOCl + Ca(OH)2
D. HOCl → H+ + OCl-
E. All of the above
The correct answer is E. All of the Above
Wastewater and Water
How about some practice calculating detention times, surface loading rates, and weir overflow rates for the following clarifiers/sedimentation tanks? 6 tanks; each tank dimensions are:
-
Overall diameter is 130 ft
-
12 ft SWD
-
17 ft deep in center
-
Weir diameter is 125 ft
Click on the thumbnail below for the answers for the clarifier math chart
Which of the following is the correct wavelength of UV for disinfection?
A. 253.7 nm
B. 372.5 nm
C. 537.2 nm
D. 725.3 nm
The correct answer is A
Which of the following describes flocculation?
A. Suspended solids that are too small to settle
B. Quiescent conditions that allow settleable solids to settle
C. Neutralizing charges
D. Growth of smaller solids into larger masses that will settle
Correct answer is D. Growth of smaller solids into larger masses that will settle
A is incorrect because this describes colloids
B is incorrect because this describes sedimentation
C is incorrect because this describes coagulation
Hypoxic zones are caused by high levels of
A. Colloidal suspended solids
B. Dissolved O2
C. Nitrogen & phosphorus
D. Pathogens
The correct answer is C. Nitrogen & phosphorus
Wastewater Treatment and CollectionA is incorrect because high levels of colloidal suspended solids cause turbidity problems
B is incorrect because hypoxic zones have low or no dissolved oxygen
D is incorrect because a breakdown in the disinfection process would lead to high levels of pathogens
Click on the thumbnail below for the answers for the chart of BOD and TSS math.
The PE for flow is ____ gpcd and PE for BOD is _____ lbs BOD/person/day.
A. 0.17 for both
B. 0.17 and 100
C. 100 and 0.17
D. 100 for both
The correct answer is C. 100 and 0.17
Wastewater TreatmentB, C, D are incorrect because the PE (population equivalent) for flow is 100 gpcd (gallons per capita per day and 0.17 lbs BOD/person/day
Which of the following lab tests is used to determine the total amount of nitrogen in our effluent?
A. TN
B. TKN
C. NO3
D. NH3
The correct answer is A
According to USEPA, the standard secondary removal efficiency is
A. 15%
B. 30%
C. 85%
D. 95%
The correct answer is C
A special thanks to Courtney Cswercko, Iowa DNR, for her presentation at the March 6, 2009 AceOps Annual Conference in Council Bluffs, IA!!! Her presentation is the source of this question.
The maximum holding time for e. Coli samples according to Standard Methods is
A. 30 minutes
B. 60 minutes
C. 6 hours
D. 36 hours
The correct answer is C
A special thanks to Courtney Cswercko, Iowa DNR, for her presentation at the March 6, 2009 AceOps Annual Conference in Council Bluffs, IA!!! Her presentation is the source of this question.
Which of the following is used for process control for activated sludge?
A. MCRT
B. Surface settling rate
C. Volatile acids to alkalinity ratio
D. Weir overflow rate
The correct answer is A
B and D are used for process control for clarifiers
C is used for process control for anaerobic digesters
The correct answer is C
The correct answer is D
The correct answer is E
It is not B because the trickling filters are not in service
B. 6
C. 4
D. 1
E. 3
| Fill-In the Missing Information | |
| Clarifiers | 6 |
| Diameter | 130 ft |
| SWD | 12 ft |
| Area | 13,267 ft2 |
| Volume | 1.19 MG |
| Weir Diameter | 125 ft |
| Weir Length | 393 ft |
| Avg Day Flow | 51.6 MGD |
| Max 30-day Avg | 100.6 MGD |
| Max Day | 153.5 MGD |
| Peak | 195.5 MGD |
| Avg Day HDT | 3.4 hrs |
| Max 30-day Avg HDT | 1.8 hrs |
| Max Day HDT | 1.2 hrs |
| Peak HDT | 0.9 hrs |
| Avg Day SLR | 650 gpd/ft2 |
| Max 30-day Avg SLR | 1,260 gpd/ft2 |
| Max Day SLR | 2,460 gpd/ft2 |
Is this how a lagoon should look? No, the surface should be open
What is the cause of this? Duckweed
What is the minimum recommended velocity in non-aerated grit chambers?
A. 0 fps
B. 1 fps
C. 2 fps
D. 10 fps
The correct answer is B. 1 fps
C is the minimum recommended velocity in sanitary sewers
D is the maximum recommended velocity in sanitary sewers
A settleometer is used to measure
A. Rate of settling in a final clarifier
B. Rate of settling in a primary clarifier
C. Sludge depth in a final clarifier
D. Sludge depth in a primary clarifier
The correct answer is A. Rate of settling in a final clarifier
CollectionB is incorrect because a settleometer is used to measure the settling rate in a final clarifier
C is incorrect because a sludge judge, not a settleometer, is used to measure the sludge depth
D is incorrect because a settleometer is not used to measure the sludge depth in a primary clarifier
1. D
2. A
What is the minimum recommended velocity in sanitary sewers?
A. 0 fps
B. 1 fps
C. 2 fps
D. 10 fps
The correct answer is C. 2 fps
C is the minimum recommended velocity in non-aerated grit chambers
D is the maximum recommended velocity in sanitary sewers
Water Treatment and Distribution
Chloramines are used for
A. Corrosion control
B. Disinfection
C. Iron and manganese removal
D. Softening
The correct answer is B
EPA estimates that the average household can save more than ______ gallons of wasted water per year (not to mention more than ______ % percent cost savings on their water bills) by fixing easily corrected problems such as leaking toilet flappers and dripping faucets.
A. 100 gallons; 1%
B. 500 gallons; 2%
C. 5000 gallons; 5%
D. 11,000 gallons, 10%
The correct answer is D
Special thanks to Iowa DNR's Water Supply Listserv - Feb 5, 2009 edition
The creamy color scale on the inside of pipes is caused by
A. Calcium carbonate
B. Iron oxide
C. Manganese dioxide
D. Magnesium carbonate
The correct answer is A
A is a standpipe
B is an elevated storage tank
According to the 10 State Standards, the minimum allowable pressure in the distribution system ______ PSI.
A. 20
B. 35
C. 40
D. 100
The correct answer is A
B, C, and D are incorrect because, according to the 10 State Standards, the minimum allowable pressure in the distribution system 20 PSI.
Water Treatment
Which of the following is used for process control for filters?
A. Chlorine demand
B. Detention time
C. g
D. Hydraulic loading rate
The correct answer is D
A is used in conjunction for disinfection
B is used for process control for sedimentation
C is used for process control with coagulation and flocculation processes
The main purpose of a rapid sand filter is to remove
A. DBPs
B. Pathogens
C. THMs
D. Turbidity
The correct answer is D. Turbidity
A is incorrect because rapid sand filters are NOT used to remove DBPs
B is incorrect because disinfection is used to inactivate pathogens
C is incorrect because rapid sand filters are NOT used to remove DBPs
Distribution
In a distribution system, opening or closing a valve or a fire hydrant too quickly may cause
A. Cavitation
B. Scaling
C. Tuberculation
D. Water hammer
The correct answer is D. Water hammer
A is incorrect because cavitation is a pump problem
B is incorrect because scaling is caused by hardness precipitating
C is incorrect because tuberculation is caused by corrosion
For questions or comments, call 515-451-7932