Wastewater Exam 03

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An operator is planning to paint the complete inside surface of his aeration tank. Its dimensions are length 50â€™, width 24â€™ and depth 15â€™. The paint to be used covers 50 sq. ft/gl. How many gallons should be bought? a) 45 b) 51 c) 69: c)69
1200 BOTTOM
1500 SIDES
720 SIDES
3420 FT2
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202)In checking for a chlorine leak on a chlorinator, what should be taken? a)Use explosive meter and look for a reading of 15. b)Wrap valve in litmus paper and watch for color change. c)Break a CO2 capsule and wait for a yellow cloud.: d) Take aqueous ammonia below valve and watch for a white cloud.
203)In checking for a leak on the discharge gas line on a digester, what procedure is taken? a)Take a lighted match to where the leak is. b)Cover pipe with petroleum jelly. c)Use aqueous ammonia below valve and watch for white cloud.: d) Use solution of soapy water and watch for bubbles.
204)What procedure would ordinarily be done every two weeks in an Activated Sludge Plant? a)Check temperature. b)Wash down weir overflow plates. c)Drain secondary clarifier(s) and scrape grease off walls. d)Clean difussers. e)No: b) Wash down weir overflow plates
205)Which is the least objectionable to receiving waters from an industrial waste plant? a) Nickel b) CN c) H2SO4 d) CO2 and Nitrogen: d)CO2 and Nitrogen
206)At what temperature and how many days do you perform a BOD test and what procedure? a)20° F in a lighted incubator for 5 days. b)40° C in a dark closet for 10 days. c)20° C in a constant temperature structure for 5 days in the light: d)20° C in a constant temperature structure for 5 days in the dark.
207)For what purpose would you add alum (Al2(SO4)3) to a sludge going to a drying bed? a)Reduce flies. b)Gives a pretty color. c)Aids in drying. d)Easier to pick. e)All of the above.: c) Aids in drying.
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210)Which of the following wastes would reduce the biological activity in a trickling filter? a) Metal plating. b) Brewery. c) Meat packing. d) Dairy wastes. e) All of the above.: a) Metal plating
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212)In the aeration tank, an operator notices the sludge is turning dark gray. What is the cause? a)Under aeration. b)Over aeration. c)Low MLVSS in return. d)High MLVSS in return. e)None of the above.: a) Under aeration
213)In the final clarifier, the sludge is â€œburpingâ€ to the surface and going over the weirs. What do you do? a)Increase aeration. b)Decrease detention time in aeration tank. c)Increase detention time in aeration tank. d)Increase p: d)Increase pumping of sludge from final clarifier.
214)At what pH range is hydrogen at itâ€™s highest activity? a)0 - 1 b)1 - 4 c)5 - 7 d)8 - 10 e)11 - 12: a)0 - 1
215)At what pH range is an anaerobic digester most efficient? a)4.4 - 5.6 b)6.2 - 6.5 c)6.8 - 7.2 d)7.4 - 7.8 e)None of the above.: c)6.8 - 7.2
216)In the treatment of chromium wastes, at what pH would ion exchange occur? a) 2 - 4 b) 4 - 6 c) 7 - 10 d)11 or above e)None of the above.: a)2 - 4
217)Digested sludge is sometimes elutriated before chemical conditioning and filtration. When this elutriated water is recirculated to the primary clarifiers it: a)increases the settleable solids to the primary clarifier. b)decreases the settle: a)increases the settleable solids to the primary clarifier.
218)In the Nitrogen cycle ammonia is produced from a)proteins. b)carbohydrates. c)sugar. d)cellulose. e)animal fats.: a)proteins.
219)In the operation of a trickling filter the fixed growth system will die off at a more rapid rate during a)winter and spring. b)spring and summer. c)summer and fall. d)spring and fall. e)winter and fall.: d)spring and fall.
220)Which of the following is most likely to be a symptom of sludge bulking? a)Clear supernant with high SVI. b)Clear supernant with low SVI. c)Cloudy supernant with high SVI. d)Cloudy supernant with low SVI. e)None of the above.: a)Clear supernant with high SVI
221)Which of the following is not used for phosphorus removal? a)Lime. b)Salt or iron. c)Potassium permanganate. d)Salts of alluminum. e)Ferric chloride.: c)Potassium permanganate
222)The gas from an anaerobic digester contains more than 40% carbon dioxide. This high CO2 content is usually accompanied by: a)good digestion and gas production. b)nothing high CO2 levels indicate that digestion is complete. c)poor diges: c)poor digestion which may lead to forming problems in the digetser.
The BOD of a wastestream entering a treatment has a BOD of 250. Primary treatment removes 18% of the BOD and the secondary treatment removes 40%. What is the BOD of the plant effluent? a)205 mg/l b)123 mg/l c)145 mg/l d)100 mg/l: b)123 mg/l
250 x 0.18 = 45 mg/l removed in primary treatment, thus 250 - 45 = 205 ml/g left
205 x 0.45 = 92.25 mg/l removed in secondary treatment, thus 205 â€“ 92.25 = 112.75 ml/l in the effluent.
What is the color of good extended aeration mixed liquor? a)Black b)Tan c)Brown d)Gray e)None of the above: c)Brown
When operating an enaerobic digester, it is important that the temperature is not raised more than one degree per day. Which of the following is the most important reason for this? a)To avoid overheating the digester contents. b)To allow the or: b)To allow the organisms in the digester time to adjust to temperature changes.
What is the best way to clean a belt when maintaining a belt driven pump and motor? a)Spray with oil and wipe dry. b)Spray with a non-oil solvent and wipe dry. c)Spray with carbon tetrachloride and wipe dry. d)Clean with soap and wate: b)Spray with a non-oil solvent and wipe dry
Which of the following would be most affected by an industrial waste? a)Activated sludge. b)Anaerobic digester. c)Trickling filter. d)Aerobic digester. e)All would be affected equally.: e)All would be affected equally.
A trickling filter is icing up in the winter time, what should the operator do? a)Could open the center valve and drain valve. b)Could open just the center valve. c)Could open just the drain valve. d)Decrease the recirculation rate.: d)Decrease the recirculation rate
An operator at a wastewater treatment plant has just repacked a pump and placed it in operation. The leakage rate from the newly packed pump was determined to the excessive. The correct procedure for tightening down the packing is? a)Tighten down bo: b)Tighten down on both sides of the packing gland slightly as required.
NaHCO3 is? a)Sodium bicarbonate b)Sodium carbonate c)sodium hydroxide d)sodium carbonate trioxide e)None of the above: a)Sodium bicarbonate
What is the first thing you would do if you found that your VA/TA ratio was starting to increase? a)Stop feeding the digester. b)Increase the feed rate to the digester c)Stop mixing the contents in the digester d)Raise the pH of the d: a)Stop feeding the digester.
A plant operator has 1 M HCL and 1 M H2SO4. What normality of each does he have? a)1 N HCL 1 N H2SO4 b)1 N HCL 2 N H2SO4 c)2 N HCL 1 N H2SO4 d)2 N HCL 2 N H2SO4: b)1 N HCL 2 N H2SO4
The operator of a wastewater treatment plant is constantly replacing the shear pins on a rectangular primary clarifier. Which of the following should the operator not do to correct this problem? a)Replace worn flights. b)Install a stronger shea: c)Drain the tank and check the condition of the chains and sprockets.
A wastewater treatment plant is just being started up. It is an activated sludge plant. How much sludge should be returned from the secondary clarifier to the aeration tank? a)1/4 of the sludge blanket b)1/2 of the sludge blanket c)None of: d)all of it
In the formula SA =VA V = the volume of the aeration tank, A = MLSS, Q = the flow. What is C? a)BOD on influent. b)BOD in primary effluent. c)Suspended solids in plant influent. d)Suspended solids in primary effluent. e)Concentra: d)Suspended solids in primary effluent
A trickling filter plant was originally built with two trickling filters. Because of increased organic loadings another filter was addded. The operator of the plant has been experiencing ponding on the filter since the filter was put on line. He has alre: b)Media too small.
When repacking a centrifugal pump, the correct placement for the water seal ring would be. a)Immediately after the first packing ring. b)Immediately after the second packing ring. c)So that it lines up with the water seal pipe hole in the: c)So that it lines up with the water seal pipe hole in the stuffing box.
The operator of an activated sludge plant is experiencing a light billowy form on the surface of his aeration tank. The effect on the sludge volume index and the appropriate corrective measure would be? a)High SVI, increase sludge wasting. b)Hi: e)Low SVI, decrease sludge wasting.
The flow to an activated sludge plant is 2 MGD. The BOD from the primary clarifier is 180 mg/l. The aeration tank holds 0.90MG and the MLVSS was found to be 3000. What is the F/M ratio at this plant? a)0.13 b)0.26 c)0.20 d)0.17: a)0.13
Food to Microorganism (F/M) =BOD (lbs/day)
MLVSS (lbs under aeration)
2MGDx180mg/lx8.34=3002=0.133
0.9MGx3000mg/lx8.34 22518
What do samples for a settleable solids and DO test have in common? a)Nothing. b)They must both be well mixed before testing. c)They should both be tested for as soon as possible after sampling. d)They should both be aerated before sa: c)They should both be tested for as soon as possible after sampling.
There is a recommended color code for the piping system in a wastewater treatment plant. What is carried in pipes that are painted green? a)Plant effluent b)Compressed air c)Lime d)Oxygen e)Digested gas: b)Compressed air
The operator of a treatment finds that a motor wonâ€™t operate. The most likely thing that he should do is? a)Check to make sure that all of the wiring is correct. b)Check the overload. c)Check to rotor by dismantling the motor. d)Sen: b)Check the overload.
Which of the following processes would give you the driest sludge? a)Rotary kiln b)Filter press c)Open drying bed d)Closed and ventilate drying bed e)Centrifuge: a)Rotary kiln
Prior to using a buret for titration, the buret should be rinsed out with which of the following? a)Distilled water b)Tap water c)A portion of the sample d)The solution being titrated (titrant) e)Sulfuric acid: d)The solution being titrated (titrant)
During an emergency condition, the operator must bypass the treatment plant. When must he notify the state division? a)Within 24 hours in writing b)Within 12 hours in writing c)Within 12 hours by telephone d)On the 15th of next month<: f)Immediately
Alarm systems at a treatment plant shall be maintained in an operable condition and a)certified quarterly as to testing and written results submitted to the division. b)certified twice annually and written results submitted to the division.: b)certified twice annually and written results submitted to the division.
Which of the following would be the least toxic when introduced into an anaerobic digester? a)Phenol b)Chromium c)Cyanide d)Sodium hydroxide e)Copper: d)Sodium hydroxide
When removing a centrifugal pump from service for a long period of time, what should the operator do? a)Close the suction valve tight. b)Close the discharge valve tight. c)Close the suction and discharge valves tight. d)Remove the dra: d)Remove the drain plug and open the air vent valve
A Secondary Treatment Facility has received permission from the Division to chlorinate the effluent on a seasonal basis. When must the plant operator notify the state? a)Annually when stopping chlorination. b)Annually when starting chlorination: d)Each time that chlorination is started and stopped
What is the specified reference for the conduction of laboratory analysis? a)The Sacremento manual for Wastewater Treatment Plant Operators. b)Water Pollution Control Simplified Laboratory Procedures. c)Standard Methods for the Examination: c)Standard Methods for the Examination of Water and Wastewater.
A representative from the division of water pollution control can inspect a wastewater treatment facility: a)anytime. b)only when the plant is manned. c)only when the certified operator is on duty. d)only during working hours. e): e)at any reasonable time.
Which peice of equipment would be used to most accurately measure out 7 ml of a given sample? a)5 ml graduated cylinder. b)10 ml valumetric pipett. c)50 ml graduated cylinder. d)10 ml graduated pipett.: d)10 ml graduated pipett.
Which piece of equipment is generally not used in a titration? a)Buret b)Magnetic stirrer c)Pipette d)Magnetic strip bar: c)Pipette
Which of the below processes is a high temperature and high pressure process? a)Elutriation b)Fluidized bed c)Wet air oxidation d)Multiple hearth furnace: c)Wet air oxidation
Which of the following is not an applicable procedure for controlling D.O. levels in an aeration tank with mechanical aerators? a)Adjustable weirs b)Two speed aerators c)Timers d)Blower speed: d)Blower speed
Which of the following is not equipment used for an Suspended Solids test? a)Buchner funnel b)Evaporating dish c)Membrane filter d)Gooch crucible: c)Membrane filter
Which of the below tests is not gravimetric? a)SS b)Total solids c)Dissolved solids d)30 min. settleability: b)Total solids
Which of the below is not a process control procedure for the activated sludge process? a)F/M b)MCRT c)COD d)Solids balancing: c)COD
What dewatering aid is generally used in a centrifuge? a)Ferric chloride b)Polymer c)Lime d)Alum: b)Polymer
A buchner funnel is used to: a)measure coliform bacteria. b)measure settleable solids. c)measure colloidal solids. d)measure mixed liquer suspended solids.: d)measure mixed liquer suspended solids.
In the use of grit as a roadfill, in terms of public opinion, which aspect of grit should be monitored? a)Its abrasive nature. b)Its ability to hold water. c)Its organic content. d)Its specific gravity.: c)Its organic content.
During chomium removal, what two pH ranges should be achieved? a)3-4 than 7-12 b)2-25 then 7-8.5 c)7.0 constantly d)1-2 then greater than 6.0: b)2-25 then 7-8.5
Which symptom would be the first sign of a souring digester? a)Decreased gas production b)Lowering pH c)Increasing V.A./alkalinity ratio d)Foaming: c)Increasing V.A./alkalinity ratio
A dark greasy foam on the aeration tank probably indicates what situation? a)Young sludge b)Old sludge c)Overaeration d)Low MLSS: b)Old sludge
Which of the types of solids below would have the closest concentration in the effluents in the influent? a)Colloidal solids b)Settleable solids c)Suspended solids d)Dissolved solids: d)Dissolved solids
Although this is true, Secondary treatment processes will reduce the dissolved solids.
The influent TSS value is 225 mg/l and the effluent TSS value is 12 mg/l, what is the % removal of TSS? a)95% b)89% c)76% d)5%: a)95%
(225 - 12) / 225) X 100 = 95%
What type of valve should be used on the suction side of a centrifugal pump? a)Butterfly b)Float c)Gate d)Kick: c)Gate
What type of sample would be most representative of a daily flow of wastewater? a)Grab sample b)24 hour composite c)Flow proportioned 24 hour composite d)12 hour composite sample: c)Flow proportioned 24 hour composite
After sludge thickening the supernatant has a solids content slightly higher than the primary effluent. What would be the best area to return that supernatant to? a)Secondary clarifier b)Primary clarifier effluent c)Primary clarifier influ: e)Both a and d
Which of the below information is not needed to calculate an SVI? a)BOD b)30 min. reading on settleometer c)MLSS d)Influent TSS e)Both a and d: e)Both a and d
An operator notices that a pump is drawing more amperage than usual which would most likely be the cause? a)Worn impeller b)Thin sludge c)Worn packing d)Packing too tight: d)Packing too tight
What is the purpose of a trickling filter? a)To filter wastewater b)To remove only settleable solids c)To contact wastes with microorganisms d)To remove heavy metals: c)To contact wastes with microorganisms
What would the BODâ€™s of the following sample be, given the following data: Initial D.O. = 7.6 mg/l Final D.O. = 4.6 mg/l ml of sample used = 3 ml a)4.6 mg/l b)30 mg/l c)200 mg/l d)300 mg/l e)900 mg/l: d)300 mg/l
(7.6 - 4.6) x (300ml/3ml) = 300 mg/l
What is the maximum depth for sludge application to a drying bed? a)2â€ - 3â€ b)3â€ - 4â€ c)8â€ - 12â€ d)2â€™ - 3â€™: c)8⬝ - 12⬝
The scale in a drawing is 1/4 â€œ = 1 foot. A square room with 6â€ per side on the drawing has how many square feet of floor space? a)692 b)240 c)576 d)144: c)576
6" / (1/4") = 24 '

24' x 24' = 576 square ft
What is the first step an operator should take before starting work on a plugged RAS pump? a)Close the suction valve b)Lock and tag out pump c)Notify the state Div. of Water Pollution Control d)Bleed out the air: b)Lock and tag out pump
How many gallons would a clarifier with the following dimensions hold? Diameter = 80â€™SWD = 12â€™ a)4,500 gallons b)60,288 gallons c)950,000 gallons d)27,394 gallons e)450,954 gallons: e)450,954 gallons
1 cubic foot = 7.48 gallons
Volume of a cylinder = pR2h = 3.14 x (40' x 40') x 12' = 60,288 cubic feet
60,288 cubic feet x 7.48 gal/cubic foot = 450,954 gallons
An operator notices clumps of septic sludge on the surface of the primary clarifier, which of the following would least likely to be the cause? a)Plugged primary sludge line b)Not enough primary sludge wasting c)Toxic load d)Warm tem: c)Toxic load
Toxic loads in general effect Secondary (biological) processes.
The storage room for chlorine containers should be: a)less than 32° F. b)the same as the chlorinator room. c)warmer than the chlorinator room. d)more than 125° F.: b)the same as the chlorinator room
What is the common name for CaO? a)Calcuim carbonate b)Hydrated lime c)Quicklime d)Calcuim hydroxide: c)Quicklime
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Sludge addition and wasting from anaerobic digesters are done at the same rate for what reason? a)Maintain a constant temperature. b)So no air is mixed with digester gas. c)Energy conservation. d)Maintain constant liquid level in dige: a) Maintain a constant temperature.

b) So no air is mixed with digester gas.

c) Energy conservation.

d) Maintain constant liquid level in digester
find anser
How would you detect a leak in a digestergas line? a)With a match b)With a drop light c)With a soapy cloth d)With ammonia: d)With ammonia
If the primary clarifier works fine but the sludge it yields is too thin, how do you cure this problem? a)Increase the detention time. b)Increase the wasting rate. c)Decrease the wasting rate. d)Chlorinate. e)None of the above.: a) Increase the detention time.

b) Increase the wasting rate.

c) Decrease the wasting rate.

d) Chlorinate.

e) None of the above.
Which of the following tests would best justify the use of the settleometer? a)D.O. b)C12 residue c)MLSS d)MLVSS e)SVI: a) D.O.

b) C12 residue

c) MLSS

d) MLVSS

e) SVI
What can an operator do to prevent conning when removing sludge from the digester? a)Start and stop the pump quickly a few times. b)Draw the sludge out very slowly. c)All of the above. d)None of the above.: a) Start and stop the pump quickly a few times.

b) Draw the sludge out very slowly.

c) All of the above.

d) None of the above.
295) Each 100 gallons of groundwater infiltration per day into a sanitary sewer system reduces the usable capacity of the system by about: a) 1 person b) 3 persons c) 5 persons d) 10 persons <: a) 1 person

b) 3 persons

c) 5 persons

d) 10 persons

e) 100 person
296) Bacteria that produces diseases are known as: a) Pathogens b) Aerobic bacteria c) Anaerobic bacteria d) Larvae: a) Pathogens

b) Aerobic bacteria

c) Anaerobic bacteria

d) Larvae
303) Which of the following is an odorous gas produced by anaerobic digestion? a) CO2 b) SO4 c) H2S d) NO3: a) CO2

b) SO4

c) H2S

d) NO3
304) Which of the following problems is caused by hydrogen sulfide gas? a) Killing algae b) Killing bacteria c) High pH values d) Corrosion of sewers, structures and equipment: a) Killing algae

b) Killing bacteria

c) High pH values

d) Corrosion of sewers, structures and equipment
305) Sand, silt and grit are mainly composed of ___________ matter. a) volatile b) colloidal c) inorganic d) organic: a) volatile

b) colloidal

c) inorganic

d) organic
306) Wastewater in which the solids have been decomposed to relatively inert solids is called: a) inorganic b) septic c) fresh d) stable: a) inorganic

b) septic

c) fresh

d) stable
307) According to OSHA, which of the following oxygen-in-air concentration is the lowest safe concentration for humans to breathe in order to avoid the hazard of oxygen deficiency? a) 7.5% oxygen b) 15.0% oxygen: a) 7.5% oxygen

b) 15.0% oxygen

c) 19.5% oxygen

d) 21.0% oxygen
308) Which of the following is not normally associated with wastewater? a) CH4 - methane b) NA2SIF6 - sodium silico fluoride c) H2S - hydrogen sulfide d) CO2 - carbon dioxide: a) CH4 - methane

b) NA2SIF6 - sodium silico fluoride

c) H2S - hydrogen sulfide

d) CO2 - carbon dioxide
309) A 15⬝ diameter sewer is flowing full and carrying a flow of 2.7 MGD. The wastewater average velocity should be: a) 3.4 ft/sec b) 5.2 ft/sec c) 6.8 ft/sec d) 13.5 ft/sec: a) 3.4 ft/sec

b) 5.2 ft/sec

c) 6.8 ft/sec

d) 13.5 ft/sec
310) A temperature reading of 95° F would be equal to ___________ on the Celsius scale? a) 30° C b) 32° C c) 35° C d) 38° C: a) 30° C

b) 32° C

c) 35° C

d) 38° C
311) What is the function of the bubbler control on a pump wet well ? a) Measures liquid flow rate and regulates pump operation b) Senses liquid depth in the wet well and regulates pump operation c) Aerates the contents: a) Measures liquid flow rate and regulates pump operation

b) Senses liquid depth in the wet well and regulates pump operation

c) Aerates the contents of the wet well to prevent septic condittions

d) Measures liquid flow rate but does not regulate pump operation

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