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70 Cards in this Set
- Front
- Back
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The first step the maintenance staff should take in properly locking and tagging out a piece of equipment is to______. |
a. Always alert the operator on duty before shutting down any equipment so as to prevent the possibility of harming personnel or affecting process performance as a result of the shutdown.
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When working in an area with two or more floor coverings, be sure that they are always______.
a. overlapping one another b. secured together c. separated from one another d. at the entrances and exits only |
b. If two or more floor coverings are required, secure them togehter to prevent trips and falls from the coverings seperating.
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when manually lifting any object, be sure to______.
a. hold it at arm's length b. keep your back bent and hold it low c. keep it close to your body and use leg strength d. keep your knees locked and bend at the waist |
c. When lifting any object manually, use your legs and keep the object close to your body in order to minimize the risk of back injury.
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Oxygen deficiency becomes a concern when the oxygen level in a confined space is less than:
a. 19.5% b. 22.5% c. 25.5% d. 28.5% |
a. Levels below 19.5% can lead to injury, loss of consciousness or death.
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Which of the following provides safety information for potentially hazardous or toxic materials?
a. CERCLA b. OSHA c. CFR d. MSDS |
d. MSDS - material safety data sheets provide information on chemical hazards, and health, and safety and environmental concerns of chemicals.
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The threshold limit value concentration for chlorine vapor is:
a. 0.1ppm b. 0.3ppm c. 0.5ppm d. 1.0ppm |
c. 0.5
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When working in confined spaces where flammable gases may be present, use only tools made of:
a. stainless steel b. lead c. iron d. a non-sparking alloy |
d. a non-sparking alloy
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In addition to the worker entering a confined space, what is the minimum number of people required to be present during a confined space entry?
a. 1 b. 2 c. 3 d. 4 |
a. 1
an entry supervisor and attendant must be present during any confined space entry in addition to the entrant. |
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Hearing protection must be made available to all employees exposed to noise levels above:
a. 85db; average over 8 working hrs b. 850db; average over 8 working hrs c. 85db; continously for 8 working hrs d. 85db at any point in the 8hr work day |
a. .85db; avg over 8 working hrs
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Recommended personal hygiene practices to minimize the risk of being infected by wastewater pathogens include:
a. only rubbing your eyes while working if you are wearing impervious gloves b. washing your hands before the beginning of your shift c. changing out of your work clothes and showering before leaving work d. reading the material safety data sheets for all chemicals used at the plant |
c. changing out of your work clothes and showering before leaving work
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Conventional activated sludge systems typically operate with a DO range of:
a. 0-1 mg/L b. 2-5 mg/L c. 4-7 mg/L d. 7-9 mg/L |
b. 0-1 mg/L
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Large debris, large floating solids, and fibrous materials are categorized as:
a. screenings b. scum c. grit d. floc |
a. screenings
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Pumps are often required to bring wastewater into a treatment plant. What types of pumps are typically used to lift influent wastwater?
a. air-lift b. centrifugal c. positive depsplacement d. progressing cavity |
b. centrifugal
centrifugal pumps are primarily used for transporting influent and effluent wastewater. |
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The time it takes for a unit volume of wastewater to pass entirely through a primary clarifier is called:
a. detention time b. hydraulic loading rate c. overflow time d. weir laoding rate |
a. detention time
detention time represents the time required for a unit volume of wastewater to pass through a tank at a given flow rate. |
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After chlorine, what is the most common effluent wastewater disinfection technique or agent used in the U.S. today?
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d. ultraviolet radiation
Its popularity has grown because of its effectiveness and the fewer safety concerns compared with chlorine disinfection. |
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The BOD laoding rate divided by the quantity of microorganisms present in the biological reactors (aeration tanks) is known as:
a. organic loading b. toxicity c. hydraulic loading d. food to microorganism ration F:M |
d. food to microorganism ratio F:M
It is the ratio of mass of organic loading to the mass of microorganisms in the bilogical reactors. |
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White, fluffy foam on the biological reactors in an activated sludge process is usually caused by:
a. insufficient biomass to treat the incoming waste b. low BOD c. high DO d. too little sludge being wasted from process |
a. insufficient biomass to treat the incoming waste
Stiff white foam typically indicates there are too few microorganisms in the system to treat the incoming waste. |
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Typical components of grit removal systems include
a. belt presses b. comminutors c. chain and flight scrapers d. bar racks |
c. chain and flight scrapers
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Daily maintenance procedures for a rectangular secondary clarifier include:
a. inspecting the drive unit and the chain and flight system b. lubricating the drive unit c. inspecting the stilling well d. inspecting all oil baths |
a. inspecting the drive unit and the chain and flight system
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The mechanism used to remove dewatered sludge from the belt of a belt filter press is commonly referred to as a(n):
a. pressure belt b. edge sensor c. doctor blade d. scum collector |
c. doctor blade
Doctor blades are typically plastic or metal edges located near the cake discharge section of a belt filter press. They are used to remove the remaining dewatered sludge from the belt before the belt is washed. |
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Healthy mixed liquor in an activated sludge process should have what appearance?
a. black with a gray foam b. dark brown, covered with a greasy tan foam c. light brown and frothy d. gray with no foam of any kind |
c. light brown and frothy
A healthy mixed liquor should have a uniform light brown color, should be slightly frothy, and should have a mild musty smell. |
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Which of the following is a typical piece of flow measuring equipment?
a. Parshall flume b. nephelometer c. downward loooking acoustic sensor d. counterweighted float-level indicator |
a. Parshall Flume
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A "dead" spot in a activated sludge biological reactor is typically identified visually as:
a. an area where conditions are very calm and no mixing is taking place b. an area where the sludge seems lighter than the rest of the reactor contents c. an area with only a small amount of foam on the surface d. an area with no foam on the surface |
a. an area where conditions are very calm and no mixing is taking place
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Healthy activated sludge has what type of smell
a. rotten egg b. sharp, acidic c. mild, misty d. antiseptic |
c. rotten egg
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The mixed liquor suspended solids (MLSS) concentration range for a conventional activated sludge process is:
a. 500-1000 mg/L b. 1500-3000 mg/L c. 5000-7500 mg/L d. 8000-10000 mg/L |
b. 500-1000 mg/L
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the surface of a healthy activated sludge reactor (aeration tank) should have what type of foam?
a. a thin layer of light tan foam b. very dark or black foam c. stiff, white foam d. thick, greasy, dark tan foam |
a. a thin layer of light tan foam
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If fine-bubble diffusers are used to introduce air into a biological reactor, the surface of the tank will typically have what type of appearance?
a. splashing, violent b. calm c. mildly agitated, partially covered with light foam d. turbulent, large bubbles |
c. mildly agitated, partially covered with light foam
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Which of the following terms refers to a hydraulic condition, typically indicated by billowing solids flowing over the effluent wier, where a portion of the flow through a clarifier experiences a much shorter detention time than the rest of the wastewater in the tank?
a. surging b. short-circuiting c. overload d. dispersion |
b. short-circuiting
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The typical range of suspended solids in domestic influent wastewater is:
a. 100-300 mg/L b. 400-600 mg/L c. 700-900 mg/L d. 1000-12000 mg/L |
a. 100-300 mg/L
suspended solids removal is one of primary process goals for activated sludge treatment. Typically raw wastewater contains approximately 100-300 mg/L of suspended solids |
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If mixed liquor is black in color and the level of DO is extremely low, this typically indicates that the mixed liquor is:
a. healthy b. recycling c. septic d. reversing |
c. septic
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Which of the following is an approprate location to collect a final effluent sample for a chlorine residual test?
a. at the chlorine injection point b. at the point where influent enters the plant c. at the downstream end of the chlorine contact tank d. at the downstream end of the aeration tanks |
c. at the downstream end of the chlorine contact tank
or just before the point of discharge |
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The target DO level in a biological reactor of an efficiently-operated activated sludge process should fall within the range of:
a. 0.0 to 1.0 mg/L b. 2.0 to 3.0 mg/L c. 4.0 to 6.0 mg/L d. 8.0 to 12.0 mg/L |
b. 2.0 to 3.0 mg/L
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Which of the following types of solids most accurately represent the microorganisms in the activated sludge process?
a. total suspended solids b. mixed liquor suspended solids c. mixed liquor volatile suspended solids d. total dissolved solids |
c. mixed liquor volatile suspended solids
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What piece of laboratory glassware is used mainly to mix chemicals and measure approximate volumes?
a. buret b. pipet c. graduated cylinder d. beaker |
d. beaker
they are suitable for mixing chemicals and measuring volumes |
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What is the maximum recommended holding time for a sample that is to be analyzed for pH?
a. none, it must be analyzed immediately b. 48hrs c. 7d d. 14d |
a. none, it must be analyzed immediately
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Given the following information, calculate the BOD of this sample:
Initial sample DO = 8.5 mg/L Final sample DO = 5.1 mg/L Amount of sample used = 9 mL Total sample volume = 300 mL a. 62 mg/L b. 85 mg/L c. 102 mg/L d. 113 mg/L |
d. 113 mgL
BOD mg/L = (Initial sample DO mg/L - Final sample DO mg/L / amount of sample used, mL/total sample volume, mL = 8.5mg/L - 5.1mg/L / 9mL/300mL = 3.4mg/L / 0.03 = 113.3 mg/L |
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The temperature of a drying oven used for TSS analysis must be kept at:
a. 104 +- 1 F b. 104 +- 1 C c. 180 +- 2 C d. 500 +- 50 C |
b. 104 +- 1C
For TSS analysis, samples must be dried to a constant weight at 104 +- 1C |
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Coliform bacteria and the procedures used to test for them are divided into the two categories of:
a. MF and MTF b. LTB and BGB c. total and fecal coliforms d. M-Endo and M-FC |
c. total and fecal coliforms
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Assume that the typical pH of the influent at your treatment plant is about 7.2. As you are reviewing new lab data, you notice that the pH in the influent this morning was measured to be 6.1. This decrease is most likely be caused by:
a. a caustic substance in the influent b. a corrosive - acidic substance in the influent c. a change in outside temperature d. too much alkalinity in the influent |
b. a corrosive - acidic substance in the influent
is typically the cause of such a large pH drop in the influent |
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The temps of wastewater that is being treated has the following effect on reaction rates of the microorganisms used in the treatment process:
a. reaction rates stay constant uuntil they stop when temps exceed 20C/70F b. reaction rates double with every 10C/18F increase in temps up to a level where high temps inhibits biological activity c. reaction rates exponentially decrease for eery 10C/18F increase in temps d. temp has no effect on reaction rates when it is in the range of 5C/41F to 30C/86F; outside of this range, all reaction rates go to zero |
b. reaction rates double with every 10C/18F increase in temps up to a level where high temps inhibits biological activity
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Which is a type of positive displacement pump:
a. axial b. turbine c. educator d. gear |
d. gear
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What is the vertical distance between the elevation of the free water surface at the suction and that of the free water surface at the discharge of a pump called?
a. discharge head b. dynamic head c. velocity head d. static head |
d. static head
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What is an air gap device used for?
a. backflow prevention b. insulation c. to prime pumps d. to seal valves |
a. backflow prevention
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How often should inactive valves be exercised?
a. daily b. weekly c. monthly d. quarterly |
d. quarterly
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In a circular clarifier, what is the function of the centrally located drive unit?
a. to operate the RAS/WAS pumps b. to adjust the height of the effluent weirs c. to rotate the sludge collection mechanism d. to rotate the catwalk to a desired location |
c. to rotate the sludge collection mechanism
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What pair of parameters is most typically used to adjust chlorine feed rates?
a. chlorine supply and temp b. sulfur dioxide supply and chlorine supply c. sulfu dioxide supply and flow rate d. chlrine residual and wastewater flow |
d. chlrine residual and wastewater flow
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When using a progressing cavity pump to pump sludge, in what condition must the pump intake be in order to insure safe operation?
a. submerged b. primed c. dry d. hot |
a. submerged
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What is the primary operational concern for using a float level indicator in an open channel?
a. heavy flows b. turbulant flow c. solids, debris, or ice d. the type of counterweight used |
c. solids, debris, or ice
The accumalation of these on the float or well can drastically skew the reading from this type of unit. |
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What equipment is typically used to control positive displacement blowers?
a. inlet valves and variable frequency drives b. multi-speed motors and variable frequency drives c. air inlet piping d. diffusers |
b. multi-speed motors and variable frequency drives
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A water-filled mechanical pump seal not only helps to prevent leaks, but also:
a. cools the material being pumped b. keeps the pump primed c. acts as a reserve water supply d. acts as a lubricant for the pump shaft |
d. acts as a lubricant for the pump shaft
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When planning to work near electrical equipment, be sure to always:
a. remain grounded to metallic equipment b. lock and tag out the equipment c. handle wires as necessary d. notify your electric power provider |
b. lock and tag out the equipment
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What is your first course of action if you see a slow constant drip from a pump shaft packing seal?
a. loosen the gland nuts b. make no adjustment c. change/adjust packing material d. fill seal with more water as needed |
b. make no adjustment
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What does a gradual increase in the bearing temp of a centrifugal blower indicate?
a. the air is becoming less dense b. the packing is loose c. the motor is simply adjusting to new inlet conditions d. there is a problem with the bearing lubrication or connection |
d. there is a problem with the bearing lubrication or connection
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Most DO probes come with an electric zero for calibration. What should be used to check the accuracy of this feature on a DO probe?
a. fresh water b. sodium sulfite solution c. Winkler DO test d. septic sludge |
b. sodium sulfite solution
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How often should the scraper arms and blades of a circular clarifier be inspected and replaced, if necessary?
a. weekly b. monthly c. quarterly d. annually |
d. annually
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A pump delivers 240 gallons per day at a static head of 275 ft. Calculate the pressure equivalent to this head, expressed in kPa (pounds per square inch).
a. 824 kPa / 119psi b. 1900 kPa / 275psi c. 3792 kPa / 550psi d. 4378 kPa / 635psi |
a. 824 kPa / 119psi
1psi = 2.31ft of water, or 1ft of water = .433psi (275ft x .433psi/ft) = 119psi |
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What type of in situ maintenance is recommended for most flexible membrane diffusers?
a. air bumping b. acid flushing d. backwashing d. eshaust heating |
a. air bumping
air bumping is the prefered method of cleaning a membrane diffuser while they are in operation |
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Which of the following indicates that the impeller of a centrifugal pump may be worn or damaged?
a. pump is deliverying too much flow b. pump is very cold c. pump is not delivering the design flow d. impeller speed is too low |
c. pump is not delivering the design flow
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A ground fault interrupter on an electrical circuit system is used to:
a. interrupt repairs if the circuit is live b. disconnect power from the circuit if there is a faulty ground line c. provide an extra ground line for a circuit d. divert power to a new circuit if the present circuit is damaged |
b. disconnect power from the circuit if there is a faulty ground line
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Which of the following causes leaking between the segment and body of a plug valve?
a. new seal seating itself b. overgreased assembly c. recently cleaned segment d. new seal ring |
b. overgreased assembly
common causes of leaking between the segment and body of a plug valve include overgreasing the assembly, corrosion, contaminants, and damage to the seal ring. |
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When working in a wet well, you should always follow what safety procedures?
a. your supervisors safety instructions b. confined space entry permit requirements c. basic plant safety procedures d. you should never work in a wet well |
b. confined space entry permit requirements
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for a given 5 day period, the BOD readings in the effluent are as follows:
Day 1 - 10 mg/L Day 2 - 12 mg/L Day 3 - 18 mg/L Day 4 - 14 mg/L Day 5 - 11 mg/L What is the average of the results for this period? a. 10 mg/L b. 12 mg/L c. 13 mg/L d. 18 mg/L |
c. 13 mg/L
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What is considered the most important form of laboratory documentation when sample results are to be reported to governmental regulatory agencies?
a. sample preparation logbook b. standards preparation logbook c. sample results worksheet d. chain of custody forms |
d. chain of custody forms
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When you recieve a phoned in complaint, what should you do first?
a. record the specific details of the complaint and the callers contact information b. correct the cause of the complaint immmediately c. alert the plant superintendant d. get the callers medical information |
a. record the specific details of the complaint and the callers contact information
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Which organizations normally issue NPDES permits to treatment facilities and industries?
a. US EPA or state environment agency b. state health department c. local government d. regional utilities authority |
a. US EPA or state environment agency
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What provides the basis for Federal regulation of wastewater treatment in the US?
a. clean water act b. discharge monitoring system c. environmental protection code d. national pollution discharge elimination system |
a. clean water act
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Your facility uses 1ton cylinders of chlorine for effluent disinfection. The average daily chlorine demand for your facility is 7 mg/L requiring an average daily dosage of 9 mg/L. Based on these averages, how many chlorine cylinders will your facility need for the month of February? The average plant flow for the month of Feb is typically 10MGD.
a. 5 b. 8 c. 11 d. 14 |
c. 11
first calculate avg amount of chlorine used per day: Daily amount of chlorine, lbs = (chlorine dosage mg/L)(flow MGD)(8.34 lb per mil.gal / mgL) = (9mgL)(10mil.gal per day)(8.34l b per mil.gal / mgL) = 750.6 lbs/day Next determine the amount in lbs used in the month of Feb: (28 days in feb)(750.6lbs/day) = 21016.8lbs/mth Finally, determine how many cylinders will be needed: 1ton = 2000lbs 21016.8lbs (1cylinder/2000lbs) = 10.5 cylinders, rounded up to 11 |
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Typically, how frequently are treatment plants required to submit Discharge Monthly Reports?
a. daily b. weekly c. monthly d. yearly |
c. monthly
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For your maintenance mgt system, labor and materials should always be available for project, emergency, and what other type of maintenance?
a. capital b. preventative c. engineering d. computer |
b. preventative
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What management technique would be most effective for ensuring positive involvement from all of your employees in a facilities safety program?
a. discipline all safety violators with suspensions b. reward the safest employee c. punish the most unsafe employee d. form a safety committee with people at different levels from all departments |
d. form a safety committee with people at different levels from all departments
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