Wastewater Treatment and Analysis, Exams of Water and Wastewater Engineering

Download Wastewater Treatment and Analysis and more Exams Water and Wastewater Engineering in PDF only on Docsity! ABC Wastewater Collection Level 3 Exam New 2024 Version Best Studying Material with All Questions and Correct Answers Occasionally some of the people on a work crew will indulge in active horseplay. This should be A. discouraged because some of the workers might not like it B. encourage because it promotes good fellowship C. permitted as it is a form of relaxation D. stopped immediately because it is likely to cause an accident ---------- Correct Answer ---------- D. stopped immediately because it is likely to cause an accident A wet well probe is usually used for ________ determination(s) of level. A. approximate B. dual point C. continuous D. single point ---------- Correct Answer ---------- D. single point The relative stability test Basic A. Requires 5 days to complete B. Involves incubation of a sample with methylene blue solution C. Is used to determine whether a sample is acidic or alkaline D. Is usually only performed on raw wastewater ---------- Correct Answer ----------- B. Involves incubation of a sample with methylene blue solution The relative stability test is often used in connection with wastewater treatment plants to A. Check for toxic materials that would interfere with the operation of the trickling filter B. Measure the oxygen demand of the plant effluent C. Test the raw wastewater D. None of the above ---------- Correct Answer ----------- D. None of the above A pump is delivering at less than the expected rate of discharge. Which of the causes listed below is incorrect? A. speed of motor too low B. pump not primed C. impeller clogged D. discharge head too low ---------- Correct Answer ---------- D. discharge head too low The gas most commonly associated with fresh wastewater is A. carbon dioxide B. carbon monoxide C. hydrogen sulfide D. oxygen ---------- Correct Answer ---------- D. oxygen The electrical disconnect for a pumping station motor can trip out under which one(s) of the following possibilities? A. clogged pump inlet B. low temperature C. strike by lightning D. worn packing ---------- Correct Answer ---------- C. strike by lightning One of the electric motors in the facility has overheated and caught fire. Select the correct sequence of steps you would take. 1. extinguish fire 2. test 3. repair 4. shut off power 5. remove tags and locks 6. ascertain cause 7. tag and lock out power A. 1, 2, 6, 4, 7, 3, 5 B. 1, 4, 6, 7, 2, 3, 5 C. 4, 1, 7, 6, 3, 5, 2 D. 4, 6, 1, 7, 3, 5, 2 ---------- Correct Answer ---------- C. 4, 1, 7, 6, 3, 5, 2 Pipe materials that are the least susceptible to corrosion by acids formed from gases generated in sewers are A. ACP B. CIP C. RCP D. VCP ---------- Correct Answer ---------- D. VCP The level of water can be measured by A. bubblers B. electrical probes C. floats D. all of the above ---------- Correct Answer ---------- D. all of the above At a pumping station equipped with centrifugal pumps, what caused the discharge pressure to suddenly increase and the discharge quantity to suddenly decrease? A. a discharge valve was closed B. a suction valve was closed C. the pump amperage was decreased D. the voltage was suddenly increased ---------- Correct Answer ---------- A. a discharge valve was closed You have been directed to examine and review the plans and specifications for a new wastewater pump station prior to the advertising for construction bids. Which of the following is of least significance to your review? A. the clearance around and above pumps, motors, valves and control switch gear D. work order system ---------- Correct Answer ---------- D. work order system The most important function of record-keeping is A. they record how much money was budgeted and how much we spent B. they record the past and provide a sound basis on which to plan the future C. they record what was done and when it was done D. they record where we've been and how we got where we are today ---------- Correct Answer ---------- B. they record the past and provide a sound basis on which to plan the future All of the following are types of starters for electrical motors except A. actuator B. autotransformer C. reduced voltage D. resistors ---------- Correct Answer ---------- A. actuator Instrumentation friction discs or clutch surfaces should be A. frequently brushed briskly with a solution of water and soda. B. kept free of oil C. oiled frequently D. roughened with emery cloth as necessary ---------- Correct Answer ---------- B. kept free of oil If a generator will not start, check for A. loose terminal connections B. shaft binding or sticking C. tripped circuit breakers D. all of the above ---------- Correct Answer ---------- D. all of the above Given the data below, what is the most likely cause of the problem? DATA: Wet well inlet increased flow because of rain Wet well unchanged at excessively high level Lead pump running Follow pump running Lead pump check valve lifting arm up Follow pump check valve lifting arm down Force main pressure remains at normal range for one pump Low-level pressure switch normal High-level pressure switch normal Electrical controls automatic A. lead pump clogged B. force main pressure too high C. follow pump clogged D. both pumps clogged ---------- Correct Answer ---------- C. follow pump clogged Given the data below, what is the most likely cause of the lift station problem? DATA: Wet well inlet has normal dry weather flow Wet well empty with flow going directly to pump suction Lead pump is running Follow pump is running Lead and follow pump check valve lifting arms are slightly above closed position Forced main pressure low and erratic Lead air compressor running Low-level pressure switch is closed Electrical controls automatic mode A. malfunctioning level control is causing pressure switches to open too soon B. malfunctioning level control is causing pumps to run out of phase C. malfunctioning level control is causing pumps to run constantly D. malfunctioning level control is causing high wet well level ---------- Correct Answer ---- ------ C. malfunctioning level control is causing pumps to run constantly The managerial function which involves devising an appropriate system of pay is A. controlling B. organizing C. planning D. staffing ---------- Correct Answer ---------- C. planning For utility records and/or rate analyses purposes, customers with similar patterns of water use are usually grouped together into classes. Which one of the following is not generally used? A. commercial B. domestic C. industrial D. retail ---------- Correct Answer ---------- D. retail The span of supervision is the A. average length of time required to be in the organization before making supervisor B. number of levels between the lowest employee and the boss C. number of subordinates for each manager D. number of supervisors in an organization ---------- Correct Answer ---------- C. number of subordinates for each manager Turbidity in wastewater is caused by A. color B. dissolved calcium C. hardness D. finely divided suspended material ---------- Correct Answer ---------- D. finely divided suspended material The gas most commonly associated with septic wastewater is A. carbon dioxide B. carbon monoxide C. hydrogen sulfide D. methane ---------- Correct Answer ---------- C. hydrogen sulfide How many cubic meters per second in 10 MGD? A. 0.44 B. 1.44 C. 4.73 D. 24.62 ---------- Correct Answer ---------- A. 0.44 Mechanical ventilation of a lift station is required to A. lower temperatures to reduce proportion of hydrogen sulfide B. reduce chlorine demand C. reduce corrosion D. increase DO in raw wastewater ---------- Correct Answer ---------- C. reduce corrosion Metal pipes often fail because of A. back siphonage B. browning movement C. galvanic action D. reverse osmosis ---------- Correct Answer ---------- C. galvanic action When a fire hydrant is operated, it should be A. just opened enough to have a flow B. opened fully C. opened halfway D. regulated to flow required ---------- Correct Answer ---------- B. opened fully If the pump bearings on horizontal centrifugal pumps are over lubricated, the most important effect is that the extra lubricant A. will result in smoother and more efficient operation of the pump B. will not make any difference in the operation of the pump C. will be wasted D. shaft or shaft sleeve will be damaged ---------- Correct Answer ---------- D. shaft or shaft sleeve will be damaged If packing is not maintained properly, A. cavitation damage will result B. impeller will corrode C. loss of suction due to air being allowed to enter pump D. shaft or shaft sleeve will be damaged ---------- Correct Answer ---------- C. loss of suction due to air being allowed to enter pump In certain situations, a supervisor encourages the employees to make their own decisions. This is considered to be A. against the rules to follow past experiences in decision-making B. span of supervision C. organizational chart D. formal organization ---------- Correct Answer ---------- D. formal organization It is generally accepted by psychologists that human behavior is goal-oriented and A. selfish B. random C. other-centered D. motivated ---------- Correct Answer ---------- D. motivated Steel tanks may be protected from rusting by A. alternately wetting and drying walls B. maintaining humidity in tank C. protective coatings D. washing tank walls ---------- Correct Answer ---------- C. protective coatings What should be the most important concern of an operator after a bypass? A. aquatic life B. clean-up procedures C. health-related effects D. odors ---------- Correct Answer ---------- C. health-related effects A supervisor could be responsible for an accident, in part or completely, by A. disregarding an unsafe work environment B. haste in requiring work performed C. overlooking a potential hazard D. all of the above ---------- Correct Answer ---------- D. all of the above Increased funds for the year are limited. However, 2 or 3 outstanding newly employed individuals are grossly underpaid for their services. How should this situation be handled? A. call a staff meeting, explain the situation and then raise their salaries B. don't give anyone a raise C. pass the word that there will be no raises but change their titles, not their duties, and raise their pay D. Say nothing and do nothing because it is none of the employee's business ---------- Correct Answer ---------- A. call a staff meeting, explain the situation and then raise their salaries When purchased materials are received by the utility, they should not be A. counted and checked against P.O.'s B. inspected C. placed on shelves where they will be used first D. recorded ---------- Correct Answer ---------- C. placed on shelves where they will be used first Disaster plans should be developed in case of A. broken sewers B. floods C. power outages D. pump stoppages ---------- Correct Answer ---------- B. floods Public relations are important because we A. want to finish our work in a hurry B. need lots of training C. must deal with the public D. like our jobs ---------- Correct Answer ---------- C. must deal with the public An organization chart for a utility can be helpful for several reasons. Which of the following is the least valid objective of an organization chart? A. to establish proper chain of command authority B. to help develop a budget C. to help in making up project schedules D. to help in scheduling emergencies ---------- Correct Answer ---------- D. to help in scheduling emergencies The presence of hydrogen sulfide in a collection system is usually caused by the A. bacterial oxidation of sulfur in the presence of dissolved oxygen B. bacterial reduction of methane in the absence of dissolved oxygen C. bacterial reduction of methane in the presence of dissolved oxygen D. bacterial reduction of sulfate compounds in the absence of dissolved oxygen ---------- Correct Answer ---------- D. bacterial reduction of sulfate compounds in the absence of dissolved oxygen Which of the following is not typical of a "submersible" pump? A. can be installed in a crooked hole B. minimizes vandalism C. quieter operation D. requires water lubrication ---------- Correct Answer ---------- D. requires water lubrication Possible types of atmospheric hazards found in manholes include A. explosion B. oxygen deficiency C. toxic gases D. all of the above ---------- Correct Answer ---------- D. all of the above Given the data below, what is the most likely cause of the problem? DATA: Wet well inlet is normal for dry weather flow. Wet well alternating excessively high and excessively low levels Lead pump starts at right level, level continues to rise, pump stops at right level Follow pump starts at right level, level drops, pump stops at right level Lead pump check valve lifting arm remains stationary in lowered position when pump starts and stops Follow pump check valve lifting arm rises when follow pump starts, goes to lowered position when it stops Force main pressure remains same when lead pump starts, increases when follow pump starts, drops to previous level when follow pump stops Low-level pressure switch normal High-level pressure switch normal Electrical controls automatic A. lead pump clogged B. force main pressure too high C. follow pump clogged D. both pumps clogged ---------- Correct Answer ---------- A. lead pump clogged Given the data below, what is the most likely cause of the problem? DATA: Wet well inlet has increased flow because of rain Wet well drops normally from weather conditions, rises much more rapidly than normal Lead pump cycles on and off at right levels faster than normal Follow pump cycles on and off at right levels faster than normal Follow pump motor shaft turns backwards when off with lead pump running Follow pump check valve lifting arm stays in raised position Force main pressure high with both pumps on, too low when lead pump is on alone Air bubbler system normal Electrical controls on automatic A. check valve in follow pump clogged B. follow pump check valve stuck closed C. follow pump electrical system wired backwards D. lead pump check valve clogged ---------- Correct Answer ---------- A. check valve in follow pump clogged Velocity may be sensed A. electrically B. hydraulically C. mechanically D. all of the above ---------- Correct Answer ---------- D. all of the above Hydrogen sulfide will exist in a system depending on the presence or absence of A. iron bacteria B. oxygen C. organic acids D. inorganic sulfides ---------- Correct Answer ---------- B. oxygen What would be the cause of a shorted winding in a motor? A. overloaded B. stalled C. foreign material in motor The settleable solids test is primarily used to A. Measure the volume of solids that may be removed by settling tanks B. Determine the BOD required for treatment C. Measure the rate of decomposition of organic volatile solids D. Determine the amount of chlorine required ---------- Correct Answer ----------- A. Measure the volume of solids that may be removed by settling tanks The standard total SS test requires the Gooch crucible fiber glass mat and solids to be dried in the oven at A. 95° C B. 103° C C. 110° C D. 115.5° C ---------- Correct Answer ----------- B. 103° C The SS content of wastewater is most accurately measured by A. Filtering the sample through a specially prepared filter; drying the filter and material retained on it in an oven at 103° C; weighing the filter; and determining its added weight caused by the solids retained B. Evaporating the sample and weighing the residue C. Centrifuging the sample and measuring the volume of solids separated from the liquid D. Distilling the sample after acidification with sulfuric acid and titrating the distillate with N sodium hydroxide ---------- Correct Answer ----------- A. Filtering the sample through a specially prepared filter; drying the filter and material retained on it in an oven at 103° C; weighing the filter; and determining its added weight caused by the solids retained The amount of sample to be used in determining SS depends on the A. Amount of grease in the sample B. Amount of SS in the sample C. Degree of turbidity of the sample D. Type of vacuum apparatus available ---------- Correct Answer ----------- B. Amount of SS in the sample The advantage of the centrifuge test for SS determination in comparison with the other method is A. Accuracy of results B. Large volume of sample it can handle C. Low cost D. Speed of answer ---------- Correct Answer ----------- D. Speed of answer The following indicator is most useful in determining pH values near neutrality: A. Bromthymol blue B. Bromcresol green C. Methyl orange D. Thymol blue ---------- Correct Answer ----------- A. Bromthymol blue If a sample of sludge is taken from a digester and allowed to stand for an hour before a pH determination is made, the result will be A. An increase in oxygen content B. A decrease in pH C. An increase in pH D. None of the above ---------- Correct Answer ----------- B. A decrease in pH Buffer capacity in water is a measure of A. Ability to resist change in pH B. Ability to hold settleable solids C. Saturation DO D. Ability to treat fluctuating BOD load ---------- Correct Answer ----------- A. Ability to resist change in pH The pH's of 6 grab samples were: 6.0, 7.5, 6.9. 5.2, 8.9 and 8.5. From this, we may determine that the pH of the composite sample was A. 4.2 B. 8.9 C. 7.0 D. Cannot be determined from the above data ---------- Correct Answer ----------- D. Cannot be determined from the above data The amperometric titration method is used to measure A. BOD. B. pH. C. Residual chlorine D. Total coliform ---------- Correct Answer ----------- C. Residual chlorine A chlorine demand test for various time periods on plant effluent samples will show A. The safe amount of chlorine that may be fed without killing fish B. The number of pounds of chlorine required to kill 100 percent of the coliform C. The amount of chlorine required to give a desired residual after a given time D. The amount of chlorine required to reduce the BOD to 10 mg/l in the effluent ---------- Correct Answer ----------- C. The amount of chlorine required to give a desired residual after a given time In determining the residual chlorine in wastewater, when either nitrite nitrogen (in amounts greater than 2 mg/l) or manganic manganese is present, the most accurate results will be obtained by A. Titration by the neutral starch-iodide method B. Nitrate thiocyanate titration at less than 20° C C. Colorimetric methods D. Orthotolidine method ---------- Correct Answer ----------- A. Titration by the neutral starch-iodide method The best procedure for determination of the DO content of a plant effluent is to analyze A. A 24-hr composite sample B. A grab sample at high flow C. A grab sample at low flow D. Several grab samples at various flows ---------- Correct Answer ----------- D. Several grab samples at various flows Standard sodium thiosulfate used in the DO test has a normality of A. 0.04 B. 0.025 C. 0.004 D. 0.0025 ---------- Correct Answer ----------- B. 0.025 Agitating a sample before performing the DO test A. Decreases the DO B. Increases the DO C. Decreases the SS D. Increases the SS ---------- Correct Answer ----------- B. Increases the DO The most reliable sample for BOD seed correction will have a DO depletion of between A. 30 and 90 percent B. 40 and 70 percent C. 20 and 40 percent D. 70 and 90 percent ---------- Correct Answer ----------- B. 40 and 70 percent The DO depletion on unseeded dilution water should be no more than A. 1.00 mg/L B. 0.02 mg/L C. 0.20 mg/L D. 0.50 mg/L ---------- Correct Answer ----------- C. 0.20 mg/L BOD incubation is at Basic A. 37° C B. 98° F C. 20° F D. 20° C ---------- Correct Answer ----------- D. 20° C The DO probe is recommended over the modified Winkler method when the following conditions are present in the A. Sample B. Sulfate C. Free Chlorine D. Intense color E. All the above ---------- Correct Answer ----------- C. Free Chlorine D. Intense color Sodium thiosulfate is used to determine Before running a BOD test, samples that are highly acidic should be neutralized to a pH of A. 8.4 B. 8.9 C. 7.0 D. 4.3 ---------- Correct Answer ----------- C. 7.0 Toxic metals in high concentration in a sample for BOD will result in A. High BOD result B. Low BOD result C. Normal BOD result D. None of the above ---------- Correct Answer ----------- B. Low BOD result The standard BOD test requires A. Pure tap water for dilution purposes B. A buffer solution and trace elements composed of iron magnesium, calcium chloride and copper to be added to the dilution water C. The pH of the dilution water to be 5.2 to 5.6 D. A water seal to be continuously provided ---------- Correct Answer ----------- D. A water seal to be continuously provided The COD test is considered a better operational control test than the BOD test because A. It takes less time to run the test B. The result are more accurate C. Everyone uses it D. The results are independent of alkalinity ---------- Correct Answer ----------- A. It takes less time to run the test COD is a good estimate of A. Nitrogenous oxygen demand. B. Carbonaceous oxygen demand C. 1st-stage oxygen demand D. 2nd-stage oxygen demand E. 20-day BOD ---------- Correct Answer ----------- E. 20-day BOD The COD test is a measure of A. Concentrated oxygen demand B. Chemical odor demand C. Clinical oxygen dosage D. Chemical oxygen demand ---------- Correct Answer ----------- D. Chemical oxygen demand Compared with the BOD, the COD of a wastewater sample is generally A. Greater B. Equal C. Less D. None of the above ---------- Correct Answer ----------- A. Greater 48. A relative stability test on a wastewater sample loses its color within 12 hr. This indicates A. The wastewater is not adequately treated for discharge to a dry stream B. The wastewater is adequately treated for discharge to a dry stream C. Nothing if the test was taken on the plant effluent D. None of the above ---------- Correct Answer ----------- A. The wastewater is not adequately treated for discharge to a dry stream 49. The methylene blue test is generally used in wastewater treatment to determine the A. Strength of digester supematant B. Amount of industrial waste in influent C. Stability of plant effluent. D. Stability of plant influent ---------- Correct Answer ----------- C. Stability of plant effluent. A certain determination made on a sample of mixed liquor from aeration tanks shows "the volume in milliliters of one gram of sludge after settling 30 minutes.to This determination is known as the A. SS test B. Sludge volume index C. Settleable solids test D. Sludge stability test ---------- Correct Answer ----------- B. Sludge volume index 51. The end point for the titration of the distillation method of the volatile acids test is A. The change to a yellow or light tan color B. The change from brown to a straw yellow color C. The change from blue to colorless after the addition of starch D. The change from colorless to pink ---------- Correct Answer ----------- D. The change from colorless to pink The indicator methyl orange is used in the test for A. Hardness B. Chlorine residual C. Alkalinity D. Turbidity ---------- Correct Answer ----------- C. Alkalinity A spectrophotometer is used to measure A. DO B. Dissolved solids C. Settleability D. Color intensity ---------- Correct Answer ----------- D. Color intensity The significance of running a fecal coliform test is A. To indicate pathogenic organisms B. To indicate recent wastewater pollution C. To indicate a measure of waste strength D. To indicate the presence of rotifers ---------- Correct Answer ----------- B. To indicate recent wastewater pollution