Basic Wastewater Operator Practice Exam 100% VERIFIED ANSWERS 2024/2025 CORRECT STUDY S, Exams of Health sciences

Download Basic Wastewater Operator Practice Exam 100% VERIFIED ANSWERS 2024/2025 CORRECT STUDY S and more Exams Health sciences in PDF only on Docsity! Basic Wastewater Operator Practice Exam 100% VERIFIED ANSWERS 2024/2025 CORRECT STUDY SET What is the predominant organism in a healthy activated sludge treatment plant? A. Stalked ciliates B. rotifers C. nematodes D. amoebas A. Stalked Ciliates A composite sample must be? A. sporadically collected in the treatment plant B. taken at one time C. analyzed immediately D. representative and sub-samples time spaced over 15 minutes apart D. representative and sub-samples time spaced over 15 minutes apart What is the standard volume for a BOD sample bottle? A. 150 mL B. 200 mL C. 300 mL D. 500 mL c. 300 mL If you have a lime slurry feed line, what is the best valve to use? A. plug valve B. butterfly valve C. RPZ dual check valve D. gate valve A. plug valve 5. If you notice a predominance of rotifers in your activated sludge sample while looking at it under a microscope, what does this indicate? A. healthy sludge B. young sludge C. old sludge D. middle age sludge C. old sludge Calculate the BOD using the given information: Initial DO: 8.3 Final DO: 5.9 Milliliters of sample used: 2 a. 360 mg/L b. 210 mg/L c. 856 mg/L d. 36 mg/L a. 360 mg/L If your activated sludge plant begins to nitrify, what conditions would you expect to decrease? A. settling in clarifiers B. chlorine demand C. BOD effluent D. TSS in effluent A. decrease the lag time for pump operation by moving the floats closer together What is the purpose of amber storage bottles? A. the color is pretty b. they are cheaper c. to protect chemicals that are sensitive to light d. so you can not see what is inside the container c. to protect chemicals that are sensitive to light Calculate SRT Given: MLSS = 2400 mg/L Aeration basin volume = 35,000 gallons = 0.0350 MG WAS concentration = 3500 mg/L WAS flow rate = 0.001 MGD A. 6 hours b. 6 days c. 24 hours d. 24 days d. 24 days How should a 1-ton chlorine cylinder be moved and stored? A. Horizontal and vertical B. vertical and horizontal C. vertical and vertical D. horizontal and horizontal D. horizontal and horizontal Calculate F:M ratio Given: Influent BOD5 = 290 mg/L Influent flow = 5.0 MGD Aeration basin MLSS = 2650 mg/L Aeration basin volume = 0.8 MG A. 0.01 B. 0.11 C. 0.68 D. 0.06 c. 0.68 What would most likely cause a submersible pump to an AMP reading that is above the optimum level? A. nothing, pumps normally run highs AMPs b. clogged impeller c. low voltage at power supply d. low flow to pump station b. clogged impeller Which of the following are non-moving parts of a running motor? A. impeller b. shaft c.windings d. stator d. stator Calculate SVI Given: 30 minute settling test = 1800 mL in a 2000 mL container MLSS = 4000 mg/L A. 200 b. 450 c. 225 d. 115 c. 225 What type of flow meters are used during normal operations of the sludge removal? a. turbine b. magnetic c. TDR d. paddle wheel b. magnetic What should be done when the bioreactor in an SBR plant is organically overloaded? a. nothing - it is normal for bioreactors to be organically overloaded b. waste more sludge c. add more fresh water d. increase effluent flow b. waste more sludge Why are approved black flow devices installed above ground level? a. ease of access b. because the plummers union requires it c. cost of vault d. to keep valves from being submerged d. to keep valves from being submerged What is the most appropriate method to decrease F:M ratio? a. decrease WAS b. Decrease influent flow c. add lime to the return sludge d. add NaOH to influent flow a. decrease WAS What is Total Kjeldahl Nitrogen (TKN) comprised of? a. phosphorous and nitrogen b. nitrogen, oxygen, and magnesium c. nitrogen, potassium, and ammonia d. organic nitrogen and ammonia d. organic nitrogen and ammonia What is the term used when the nitrifiers convert the ammonia to nitrites and nitrates under aerobic conditions? A. nitrification B. denitrification C. assimilation D. neutering a. nitrification What is the term used when bacteria convert nitrates and nitrites to nitrogen gas under anoxic conditions? a. nitrification b. denitrification c. assimilation d. neutering b. denitrification What is the chemical symbol for hydrogen sulfide? a. HFS b. H2SO4 c. H2S d. HNO3 c. H2S How should lime slurry lines be cleaned? a. replace feed line after each shift b. flush with water c. clean feed line with a stiff bristle brush d. flush with muriatic acid b. flush with water The ammonia loading on a plant is increasing. What should the operator expect regarding the amount of alkalinity in the system? a. the alkalinity will decrease b. the alkalinity will remain the same c. the alkalinity will not change d. ammonia has nothing to do with alkalinity a. the alkalinity will decrease What is a check valve? a. a valve that is closed by the pressure of a fluid so that the fluid does not flow back in the direction it came from b. a valve to check the flow volume of a pump c. a valve that allows for flow of water to go in multiple directions d. a valve that creates a check point for sampling a. a valve that is closed by the pressure of a fluid so that the fluid does not flow back in the direction it came from What should an operator do when excess solids enter a media filter? a. improve the performance of secondary treatment units b. increase the backwash frequency c. employ air-scour and/or surface jetting d. put additional filters on line b. increase the backwash frequency Suction lift pressure is measured from the center line of the pump to _____? a. center of discharge line at ground level b. center of the power line c. top of the highest manhole lid d. bottom of the lowest manhole lid A. center of discharge line at ground level What type of supply pipe is recommended for gaseous chlorine & water? a. galvanized steel b. polyvinyl chloride c. rubber d. stainless steel b. polyvinyl chlorine (PVC) Which activated sludge processes handles shock loads of high organic waste most effectively? a. bardenpho b. conventional c. SBR d. complete mix b. conventional What occurs to hydrogen sulfide when it reacts with chlorine? a. sulfur and hydrochloric acid are formed b. an explosion c. a pleasant odor d. nitrification a. sulfur and hydrochloric acid are formed c. flush with cold water for 15 minutes d. flush with sodium dioxide solution to neutralized the chlorine c. flush with cold water for 15 minutes Diseases potentially carried by wastewater include? a. typhoid fever b. dysentery c. cholera d. all of the above d. all of the above What immediate first aid should be given for burns? a. hot compress b. clean with an antiseptic c. flush with cold water d. cover tightly with bandage c. flush with cold water What is one of the most likely causes of electric motor failure? a. running too long b. short run times c. excessive moisture d. dry conditions c. excessive moisture What is a valve called that allows water to flow in one direction only? a. plug valve b. butterfly valve c. check valve d. gate valve c. check valve What is one component of a centrifugal pump? a. impeller b. primer c. hose bib d. piston a. impeller Chlorine gas is what? a. lighter than air b. same weight as air c. heavier than air d. purple in color c. heavier than air The highest concentration of algae growth in a facultative lagoon is usually observed where? a. near the top b. near the middle c. at the bottom d. at the effluent a. near the top Common hydraulic detention times for primary clarifiers range from? a. 1-2 hours b. 5-10 hours c. 18-24 hours d. 2-3 hours d. 2-3 hours Which gas is produced in an anaerobic digester? a. ethanol b. alcohol c. methane d. hydrogen sulfide c. methane The rock in a trickling filter is usually placed where? a. around the outer edge of the filter b. in the center of the filter c. on the tile underdrain system d. at the discharge of the filter c. on the tile underdrain system Chlorine is primarily used to what? a. increase pH b. increase dissolved oxygen c. disinfection d. decrease solids c. disinfection What is the purpose of heating and mixing a primary anaerobic digester? a. to slow down the digestion rate b. to increase the digestion rate c. to allow for more room in the digester d. to increase effluent quality b. to increase the digestion rate Name a device which is used to measure the flow of wastewater? c. sulfides What reagent is used to determine chlorine residual? a. diethyl-p-phenylene diamine or DPD b. sulfur dioxide (SO2) c. sodium metabisulfite (Na2S2O2) d. sodium bisulfate a. diethyl-p-phenylene diamine or DPD What test is typically never performed on wastewater influent? a. BOD b. TSS c. Fecal coliform d. Oil & grease d. O&G A local college has an outbreak of giardia in the water system. A hose that was connected to a spigot found in a grease trape was determined to be where the bacteria entered the system. What is this an example of? a. cross-connection by back siphonage b. cross-connection by back pressure c. cross-connection from an unapproved treatment system d. normal system operation a. cross-connection by back siphonage Considering the layout and flow diagram for the complete treatment plant, oxidation ditch plants would be most similar to which of the following? a. SBR b. plug flow c. Extended aeration d. contact stabilization c. extended aeration A WWTP flow is 5.0 MGD. How many gallons per minute is this? a. 3472 gpm b. 0.24 gpm c. 57.8 gpm d. 7200 gpm a. 3472 gpm A trickling filter arm is moving slow. How do you speed it up? a. add more orfices on the distribution arms b. close orifices on the distribution arms c. decrease recirculation d. increase recirculation d. increase recirculation What is the best way to clean up a polymer spill? a. with bleach b. with phosphate detergent c. with paint thinner d. with a chemical absorbent d. with a chemical absorbent How do you mix acid and water? a. add acid to water slowly while stirring to dissipate heat b. water to acid c. do not mix d. pour both into a beaker at the same time a. add acid to water slowly while stirring to dissipate heat In an RBC plant, the microscopic investigation revealed some amoebas and flagellates in the first set of discs, the second set showed free-swimming ciliates and some rotifers, the third set had blood worms and nematodes. What is this an indication of? a. normal operation b. toxic waste entering the plant c. flow running too slow through discs d. flow running too fast c. flow running too slow through discs Your system serves 2740 people and an industry contributes 300 lbs/day of BOD. How many pounds of BOD are received at your plant? a. can not calculate, not enough information b. 766 lbs/day c. 466 lbs/day d. 383 lbs/day b. 766 lbs/day When you install a new packing gland, you notice that there is a slow, steady stream of water flow coming out of the packing area. What is this an indication of? a. you need more packing b. you need to tighten the bolts until no water is leaking out c. normal operation d. you need to loosen the bolts until a fast, heavy stream of water is spraying out of the packing c. normal operation When collecting a sludge sample, where is the most representative sample location? a. at the beginning of the aeration basin b. at the end of the aeration basin b. to prevent contamination of potable water systems A horizontal centrifugal pump has "rope" packing. When the pump is operation water slowly drips from the packing glad. What does this indicate? a. the packing bolts or nuts on the packing gland are properly adjusted b. the packing bolts or nuts on the packing gland are not properly adjusted c. the pump needs more coolant d. the pump is not operating efficiently a. the packing bolts or nuts on the packing gland are properly adjusted Why are check valves used in conjunction with centrifugal pumps? a. to increase head pressure b. to cause more work for the installers c. to prevent wastewater in the discharge line from flowing back through the pump d. to allow for less water to leave the pump c. to prevent wastewater in the discharge line from flowing back through the pump What should an operator do if a fuse continues to blow? a. inspect the affected equipment to determine the cause b. replace it with a larger capacity fuse c. nothing. fuses blow from time to time d. keep it a secret. it may cause you more work a. inspect the affected equipment to determine the cause Valves should be closed slowly to avoid what? a. water sledge b. water saw c. water blasting d. water hammer d. water hammer Assuming a constant suction head, the discharge of a centrifugal pump a. will increase with a decreased in discharge head b. will decrease with a decrease in discharge head c. will decrease with an increase in discharge head d. will increase with an increase in discharge head c. will decrease with an increase in discharge head A positive displacement sludge pump should never be placed into operation a. true b. false c. with the discharge valve closed d. with the discharge open c. with the discharge valved closed How does the addition of chlorine, acid, carbon dioxide, or sulfuric acid effect the pH of wastewater? a. increase the pH b. decrease the pH c. pH remains the same d. normalize the pH b. decrease the pH controlling the sludge wasting rate by constant mixed liquor suspended solids or MLSS concentration involve maintaining a certain concentration of what? a. the volatile suspended solids in the reactors or aerationt anks b. BOD c. fecal coliform d. IDSE a. the volatile suspended solids in the reactors or aeration tanks Which of the following organisms should not be present in a healthy lagoon treatment system? a. algae b. fungi c. amoebas d. coliform b. fungi How will the BOD level be affected under ice and snow cover normally? a. slowly increase b. slowly decrease c. rapidly increase d. rapidly decrease a. slowly increase What controls the rotational speed of the air drive biological contactor (RBC)? a. water volume b. bacteria growth c. air volume d. amount of suds c. air volume What are chloramines? a. combined chlorine b. disdain c. not your chlorines d. separated chlorines a. combined chlorine What condition increases chlorine demand? c. horizontal centrifugal pumps do not have bearings d. the bearings on horizontal centrifugal pumps are sealed and do not require lubrication a. may cause overheating and possible failure of the bearings What is the most likely cause of rising sludge in clarifiers? a. young sludge b. old sludge c. middle age sludge d. slime b. old sludge the amount of BOD in sludge entering a digester would be an indirect measure of what in the digester? a. plant matter b. food c. oxygen d. microorganisms b. food How can chemical coagulation dose be initially estimated? a. trial and error b. jar test c. bucket test d. SWAG b. jar test What type of equipment should be calibrated daily at the treatment plants? a. portable DO probe/meter b. AMP meter c. rain gauge d. staff gauge a. portable DO probe/meter What is the ash content remaining at the end of a VSS test equal to? a. inorganic solids b. organic solids c. semi-volatile organics d. volatile organic compounds a. inorganic solids What does a chlorine demand test indicate? a. the amount of chlorine required to give a desired chlorine residual after a given time b. the amount of chlorine required to give a desired chlorine dosage after a given time c. the amount of chlorine required to meet EPD requirements d. the amount of chlorine required to give chlorine residual after 15 minutes a. the amount of chlorine required to give a desired chlorine residual after a given time What coats granular filter media with a biological slime used to filter wastewater? a. biological slime composed of soluble BOD and ammonia b. detritus c. grease d. clay a. biological slime composed of soluble BOD and ammonia In the membrane filter method how is the number of coliforms estimated? a. by the number of yellow wells b. by counting the blue/green colonies that appear on the filter after incubation c. asking the lab director d. the membrane filter method is not used to determine the number of coliforms b. by counting the blue/green colonies that appear on the filter after incubation What is the appearance of young sludge? a. dark brown, thick foam b. light brown, thin, frothy foam c. chocolate brown, little-to-no foam d. no foam b. light brown, thin, frothy foam