Wastewater D License Exam 100% VERIFIED ANSWERS 2024/2025 CORRECT, Exams of Business Administration

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Wastewater D License Exam

100% VERIFIED ANSWERS

2024/2025 CORRECT

How many PPB equals one PPM? One thousand parts per billion equals one part per million If the bubbler system air supply line at the wet well is clogged, what will this cause the pump to do? Pressure build up in the supply line would signal more water column then there really was, causing the pump to run longer than necessary, possibly not kick off and run continually If the bubbler system air supply line at the wet well has a hole in it above the water level, what will this cause the pump to do? It would cause a low pressure reading showing a lower water level then there really is, or possible not even kicking on the pump What is the best way to keep within the operating budget? keep list of purchases and expenses to date during fiscal year comparisons should be made with budget allocations to avoid excess purchases review purchases monthly and compare to budget If a diaphragm pump has 2 check valves open, what will the pump do? It would not pump properly because 1 check valve should be shut while the other is open A suction lift pump on the inlet side normally reads 2in of mercury on the psi vacuum gauge but not reads 3in of mercury. What is the problem with the pump?

A higher vacuum than normal may indicate a partially plugged or restricted suction line. A lower vacuum may indicate a higher wet well level or a worn pump impeller or wearing rings. One mg per L equals how many pounds per 1 MG?

What is the proper way to put packing in a pump? cut the packing rope about 45 degree angle, place around shaft, be sure to offset/stagger the next joint from the previous How many drips of water should you have coming out of a packing seal? no drip on a mechanical seal How many drips of water should you have coming out of a packing seal? 2 what the operation and maintenance manual recommends A one horsepower motor that runs on 110 volts using 10 amps has what efficiency? most motors run from 80-95% efficiency A motor that has 440 volt supply is usually what phase of power? 3 phase NPDES National Pollutant Discharge Elimination System the regulatory agency document issued by either a federal or state agency which is designed to control all discharges of pollutants from point sources into US waterways NPDES permit What is the name of our operating permit? NPDES

What is the best way to promote safety in the workplace? the supervisor needs to be safe and promote safety in such a manner to get the employees involved What is normally used to raise the pH in sludge? lime What is the common device used to measure the effluent of a lagoon? v notch weir What concentration of H2S is unsafe to humans? death in a few minutes at 0.2%. Paralyzes respiratory center What is the minimum O2 concentration that is safe for workers to enter a manhole? If O2 is less than 19.5%, do not enter space without respiratory protection. Normal air contains 20.93% of O2. Normal air contains ______% of O 19.5% What knob is turned to control the usage of chlorine applied? rotameter Can you store BOD at 4C for 48 hours? yes What is the minimum velocity of the water flow for a grit chamber and the maximum flow? 1.0 feet per second minimum 1.5 feet per second optimum 2.0 feet per second maximum How many mg/L equals one grain per gallon? 17.1 mg/L

Dissolved oxygen increases when the temperature __________ decreases You can tell if a clarifier scraper arm is working by what means? the simplest is to visual check to see if the scum scraper arm is moving properly check into foam If the sludge is thick or thin, then what does this tell you about the sludge scraper? possible answer is the flights are damaged or the speed of the scrapers(flights) need to be increased if sludge is too thick or slowed down if the sludge is too thin aging and maturing of a body of water eutrophication eutrophication aging and maturing of a body of water If the effluent from a treatment facility contained 5mg/L of BOD, what effect would this have on the receiving stream? little effect If you are doing a test and add one drop of chemical at a time, what is this method called? titration If doing a winkler or azide method after adding the first 2 chemicals and the contents of the bottle turn white, what does this mean? no oxygen left in bottle, it has all been consumed How far from a well should a sewer main be?

300 feet a connection between a potable water system and a nonpotable water supply cross connection a disease causing bacteria pathogenic What diseases are considered to be waterborne? Giardia and Cryptosporidium Typhoid, Hepatitis, Cholera What are the 3 main components in fertilizer that are in sludge? nitrogen, potassium, phosphorus application of the various soil and plant sciences to soil management and crop production, scientific agriculture Agronomy If the filter fecal test is run, what color would the fecal coliform show up as? blue What is another name for non-filterable solids? suspended solids If you switch any lead on a three phase motor, what is the result on the motor rotation? it will reverse rotation What type of plant has these steps: MLSS in aeration, MLSS no aeration, MLSS in aeration? step feed aeration the electromotive force (EMF) and is the electrical pressure available to cause a flow of current (amperage) when an electrical current is closed

voltage Where is the appropriate place to store a self contained breathing apparatus (SCBA)? an approved casing hanging outside a chlorination room and unlocked How do you measure the amount of CL2 available in cylinders? the cylinders are on scales, you determine the beginning weight and subtract the remaining balance to give you the available Cl What is the chemical symbol for chlorine? Cl Two pumps are parallel to each other. Each one produces 300 gpm with 100 ft head. What would be the combined gpm? over 300 gpm but less than 600gpm What is the purpose of thickening sludge? to make it economically feasible What is the significant problem of having scum on the top of a pond? it prevents sunlight from penetrating the algae How far should a sewer line be from a water main? 50' separation or 10' horizontal and 18'' separation of sewer lines to water lines when they cross or meet at joints What is the best way to get rid of algae? the first choice is chlorinating or alternative use is copper sulfate In what measurements is fecal reported? the MPN in Colony Forming Units (CFU) in per 100 mL MPN

most probable number What is the purpose of disinfection? to reduce pathogenic diseases for safer human contact What is the purpose of sterilization? to kill all organisms and bacteria A piston pump is also called ......... a reciprocating pump What pump is used for pumping sludge? reciprocating pump What is the highest and lowest time of DO in a lagoon? Class lecture states that 3pm is the highest and 3am is the lowest test states that 6pm is the highest point and 6am is the lowest What part of a centrifugal pump is used to discharge water? Volute-collects wastewater discharged by pump impeller and directs flow to pump discharge What is the major cause of bearing failure in a motor? improper lubrication over lubricating an electric motor 1 horsepower equals how many watts? 746 A piston pump is a ___________ displacement pump. Never operate it against a ________ discharge pump, valve, and/or pipe. It could be damaged by excessive pressure. Also, the suction

valve should be ____ when the pump is started. Otherwise an excessive suction or vacuum could develop and cause problems. positive closed open What is the BOD removal efficiency of a lagoon? 60 - 70% Why should you decant a digester? to thicken biosolids so more economical to dispose of water Which of the following is not a form of the hydrologic cycle? a. evaporation b. precipitation c. absorption d. percolation absorption When should you lubricate motors? what is recommended by the manufacturer the addition of oxygen, removal of hydrogen, or the removal of electrons from an element or compound. oxidation In wastewater treatment, organic matter is ___________ to more ______ substances. oxidized stable bacteria that can either use dissolved molecular oxygen or oxygen obtained from food materials such as sulfate or nitrate ions

facultative bacteria What is neutral pH? 7 What is the major problem with using UV disinfection? the cost of the operation and bulbs are expensive What is not able to be removed by a treatment plant? dissolved solids A sudden change in _________ of 10-20 mg/L may indicate a problem is developing in a pond and a warning that the pH will rise in 2 to 3 days? alkalinity waste material which comes mainly from animal or plant sources organics Hydrogen sulfide gas is noticeable by what characteristics? rotten odor smell, 2-15 minutes at .01% impairs sense of smell and is near to the ground What is the minimum DO for fish to survive? 5 to 7 parts per million or mg/L What book do you use to do lab tests? standard methods What is the purpose of riprap? prevention of emergent weeds and levee maintenance and repair and to prevent erosion a plate put between two flanges with a hole in the middle used to measure the rate of air flow through the pipes orifice

What is another name for total suspended solids? non filterable solids How do you check for a chlorine leak? tie a rag on a stick, dip the rag in a strong ammonia solution and hold the rag near hoses, fittings, and suspected leakage points. It will emit a white gas if there is a leak What is the maximum dry tons allowed to be applied in one year? 2 dry tons per acre How much heavier is chlorine compared to air? 2.5 times heavier What is the temperature of an incubator? 20 degrees celsius. This is the temperature in which you run the BOD tests How often do you need to renew your license? 3 years and 30 credit hours for renewal Wastewater is what percentage of water? 99.9% What is an Imhoff cone? used to measure settleable solids measured in mL/L What is the mandatory years for keeping records for NPDES? 5 years What regulates the rules of hauling sludge? 503 EPA Primary clarifier requires __ min-. hour detention time

45 min-1.5 hours What is the diameter of a manhole? 48 inches or greater, min diameter of access is 22 inches ft per sec recommended on grit chambers? 1ft per sec two conditions required to be septic pH below 7, no DO _ foot depth in lagoons will allow sunlight to penetrate and produce algae. 3 _ ft of freeboard at highest point of water 2 fire hydrant needs to be ___ or possibly ___ ft away from a lagoon 200, 300 A ____ must be posted on all 4 sides of a lagoon and one posted every 4 feet sign best chemical used to kill duckweed copper sulfate recommended size of rock for riprap 4 - 6 in diameter How many grab samples collected during the same week required when testing sludge? 7 Geometric means of density of fecal coliform shall be less than ____________ of total solids.

2,000,000 CFU

The best pump to use to pump raw sludge is __________ _______________ pump positive displacement Class _ biosolids can be disposed of anywhere A Class _ biosolids have limitations on disposal. B Oxygen concentration in breathing is _.%, and must not fall below normal breathing of _.%

used to measure the flow of liquid in an open conduit parshall flume Both _______ and __________ biological reactions may occur in a sewage lagoon aerobic and anaerobic A _ ________ motor will have its direction or rotation reversed if any 2 lines are interchanged 3 phase Any stream will purify itself within _ miles 5 Material collected on bar screens and skimming from primary clarifiers is properly disposed by

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burying A __________ sewer system is a system in which storm water is carried in a system separated from that carrying sewage

separate Solids subject to decomposition are.... organics Flow velocity of _ ft/sec is necessary in a sewer to prevent solids from settling and accumulating on the bottom 2 Fresh waste water is usually slightly _________ alkaline _____ is necessary for the proper functioning of a stabilization of oxidization ponds. algae _____________ pump motors can be damaged by overloading caused by operating the pump with too low discharge pressure. centrifugal Samples for making lab tests should be ______________ of the sewage to be tested. representative __ is measured in mg/L and the ______ cone is measured in mL/L DO Imhoff ____ is added to water to increase the pH lime If acid is spilled on the floor, immediately wash with _____ and neutralize with ______ ________________. water sodium bicarbonate (baking soda)

______ in digesters occurs when sludge withdrawal is too fast coning _______________ ponds are aerobic on top (oxygen present) and anaerobic (oxygen not present) on bottom facultative theoretical time it would take the flow to completely displace the effective volume of the tank detention time used to determine suspended solids' ability to separate from the liquid in the final clarifier settleometer PPM (parts per million) equal _/ mg/L Pretreatment consists of 3 things bar screen, comminutor, grit chamber the rate at which organisms use the oxygen in water or wastewater while stabilizing decomposable organic matter under aerobic conditions, measures the organic strength of wastes in water biochemical oxygen demand (BOD) calculation which indicates the tendency of activated sludge solids to thicken or become concentrated during the sedimentation/thickening process SVI-sludge volume index indicates the settleability of a sludge in a secondary clarifier of effluent the weight in grams of one mL of sldge after settling for 30 minutes SDI- sludge density index, SDI=100/SVI Food to microorganism ratio, a measure of food provided to bacteria in an aeration tank

F/M ratio ______ in sewer lagoons serves the purpose to replenish DO in water algae molecular (atmospheric) oygen dissolved in water or wastewater dissolved oxygen (DO) What will cause the most wear on pump impellers? grit sewage Emergent vegetation on the pond bottom, such as cattails, may be best controlled by keeping the depth greater than _ foot 2 an opening between drinking water supply and the point of use in a wastewater treatment plant. This gap prevents the contamination of drinking water by backsiphonage because there is no way wastewater can reach the drinking water. Usually the gap is two times the diameter of the pipe air gap gathering together of fine particles after coagulation to form larger particles by a process of gentle mixing flocculation clumping together of very fine particles caused by the use of chemicals. The chemicals neutralize the electrical charges of the fine particles, allowing them to come closer and form larger clumps coagulation oxidation by aeration will remove what? hydrogen sulfide What kind of impeller is on most pumps? open

On a centrifugal pump, water enters what? eye of the impeller allows water supply to enter packing gland and get to shaft for lubrication lantern ring on motor After repairing water main, when line was shut off, _______________ should be done disinfection High rate filters are __ gal/min per sq ft 15 On a 150 lb Cl2 cylinder, it has a fusible plug that will melt at what temperature? 160F ____ consists of sand, gravel, and eggshells. grit The indicator methyl orange is used to test for _________ hardness How do you identify a properly maintained pond? definite green color Population equivalent equals __ . Positive displacement pumps should never be started against a _________ _______ closed valve ____________ ____ are installed in a pump should never be started against a closed valve wearing rings

formation and collapse of a gas pocket or bubble on the blade of an impeller or the gate of a valve. The collapse of this gas pocket or bubble drives water into the impeller or gate with a terrific force that can cause pitting on the impeller cavitation the only pump that can be operated against a discharge pump centrifugal pump a soil conditioner and has some fertilizer value sludge used to measure pH, NO3, and NH spectrometer ___ gal/per day/ per person water usage per design 100 Average incoming strength of wastewater BOD 200 - 250 mg/L average incoming strength of wastewater TSS 200 - 250 mg/L Natural domestic wastewater has__-__ mL of ammonia NH 20 - 25 Domestic wastewater is at a pH between .... 6.5-7. The main purpose of an operator is to.. protect the downstream user ___________ is caused by feeding the digester too fast

foaming __ psi is minimal amount on main water lines, a lesser amount will cause contamination throughout the whole system 20 the two highest organic producers of high BOD milk and blood not only a poisonous gas, but will also cause corrosion in the system hydrogen sulfide gas the physical appearance of ______ sewers are dark brown or black in color, usually with a disagreeable odor septic type of biological treatment activated sludge Appreciable quantities of septic sludge "__________" to the surface of primary settling may indicate the sludge is not being pumped in sufficient quantities burping Fish life is dependent on oxygen dissolved in water in which they live. The dissolved oxygen must be present in at least _ to _ parts per million 5 to 7 An operator who is to clean a wet well in a lift station that is 20 feet deep should ___________ before entering ventilate purpose of sewage treatment to prepare sewage for safe disposal for receiving streams

the brownish flocculent culture of organisms developed in an aeration tank under controlled conditions activated sludge ___________ sedimentation is a physical process. __________ sedimentation is a biological process. ____________ is a chemical process. primary secondary chlorination _____ in a sewage lagoon serves the purpose to replenish dissolved oxygen in water algae Sludge applied to land, ___ feet from well, sinkhole, lake, or pond. ___ feet from a dwelling 300 150 If one layer of packing were placed on top of another layer, what would possibly happen? scaring of pump shaft How do you store a pH probe? DI water during use and buffer solution when stored for a period of time Oxygen deficiency becomes a concern when the oxygen level in a confined space is less than? 19.5% Which of the following provides safety information for potentially hazardous or toxic materials? MSDS

Which of the following potentially hazardous chemicals is a hydrocarbon and may be found in a manhole? methane If your one ton chlorine cylinder is leaking what type of repair kit should you use? B Large debris (sticks, rocks, etc), large floating solids, rags, strings, cloth, etc. are categorized as? screenings The time it takes for a unit volume of wastewater to pass entirely through a system is called? detention time Many times pumps are used to bring wastewater to the treatment plant. What types of pumps are commonly used to lift influent wastewater? centrifugal After chlorine, what is the most common eff wastewater disinfection technique or agent used in the US today? UV radiation White fluffy foam in an activated sludge process treatment tank is usually caused by? insufficient biomass to treat What describes an activated sludge treatment tank process where aeration and secondary clarification occur in the same tank? sequencing batch reactor Sewage is approximately _.% water 99.9% Healthy mixed liquor in an activated sludge plant should have what appearance?

light brown and frothy A facultative lagoon achieves most of its oxygen from? photosynthesis Hydrogen sulfide gas is not only a poisonous gas, but it will also cause? corrosion in the system Healthy activated sludge has what type of smell? mild, musty Hydrogen sulfide has the odor of? rotten egg Which of the following is a typical flow measuring device? a. nephelometer b. parshall flume c. downward looking acoustical sensor d. counterweighted float level indicator b, c, d If mixed liquor is black in color and the level of DO is extremely low, this typically indicates that the mixed liquor is? septic Pick the chemicals that can be used to help rid a new oxidation pond of areas that are septic? sodium nitrate or ammonia nitrate A grab sample is a reliable representative indicator of how your plant is operating... at the time the sample was taken What is the maximum hold time for the testing of pH?

none, must be done in the field The temperature of a drying oven used for TSS analysis must be kept at? 104C The typical influent pH of your facility is around 7.2 SU. As you review the morning's data, you see the pH has decreased to 6.1 SU, this was probably caused by? a corrosive acid substance in the influent What is the minimum number of standards that shall be used to calibrate a pH meter? two 18 mg/L is equal to how many PPM? 18 What is the standard used to perform a winkler method dissolved oxygen analysis? .025 N sodium thiosulfate Compacted and hardened sludge in a hopper may be caused by: excessive quantities of grit in the sludge too infrequent pumping What is the vertical distance between the elevation of the free water surface at the suction and that of the free water surface discharge of a pump called? static head Which of the following is a type of positive displacement pump? a. axial b. turbine c. piston d. centrifugal

piston Which pair of parameters is typically used to adjust chlorine feed rates? a. chlorine supply and temperature b. sulfur dioxide supply and chlorine supply c. sulfur dioxide supply and flow rate d. chlorine residual and wastewater flow d. chlorine residual and wastewater flow Chlorine gas is a? yellowish green gas 2.5 times heavier than air The formation and collapse of gas pockets or bubbles on the blade of a centrifugal pump's impeller is known as what? cavitation What is your first course of action if you see a slow constant drip from a pump shaft with a packing seal? make no adjustment When planning to work on or near electrical equipment, be sure to always... lock and tag out the equipment Which of the following indicates the impeller of a centrifugal pump may be worn or damaged? a. pump is delivering too much flow b. pump is very cold c. impeller speed is too low d. pump is not delivering the design flow d. pump is not delivering the design flow You have just rewired the motor of a centrifugal pump. The pump is now running but generating little pressure and flow. What is the most likely cause?

wrong direction of impeller rotation from improper wiring When performing your own lab analysis, your testing methods must conform to? EPA and standard methods What provides the basis for federal regulation of wastewater treatment in the US? Clean Water Act Water seal connections to wastewater pumps should not connect directly to the city water supply because: wastewater may be drawn back into the water system As a manager, how will developing good public relations assist your facility? it will sustain public support for your facility By law, operational records for your lab and facility must be retained for? 3 years What is the primary function of the wastewater treatment facility operator? to maintain the requirements set forth in the plant's NPDES permit When organic wastes are discharged to receiving waters, oxygen is depleted by... bacteria Three diseases potentially carried by wastewater typhoid fever, dysentery, cholera Centrifugal pump parts include: a. diaphragm b. impeller c. piston d. rotor

impeller A valve that allows water to flow in 1 direction only check valve A RBC plant is what type of plant? rotating biological contactor Which of the following forms of plant life is necessary for the proper functioning of a facultative wastewater lagoon? a. algae b. cattails c. weeds d. muskrats algae Which gas is produced in an anaerobic digester and can be used as fuel? methane What type of sewer accepts both domestic water and stormwater? combined sewer Filamentous bacteria may begin to dominate an activated sludge system under this condition? low dissolved oxygen What should an operator's top priority be when making operation decisions? protecting public health The ash content remaining at the end of a volatile suspended solids test is the same as the? inorganic solids Mechanical ventilation of a lift station is used to...