Water Treatment Plant Operator Exam Questions With Answers Latest Updated 2024/2025 (Graded A+)

Water Treatment Plant Operator Exam Questions With Answers Latest Updated 2024/2025 (Graded A+) What is used as a chemical coagulant? - Answer Alum The correct order of treatment in a surface water plant is... - Answer Coagulation, Flocculation, Sedimentation and Filtration In determining the proper dosage of alum, the most useful test is the____________ test. - Answer Jar If sludge is not continually removed from the sedimentation basin, its accumulation results in? - Answer Turbidity The most widely used coagulant is.... - Answer Aluminum sulfate Optimum flocculation requires: - Answer Gentle Agitation Dissolved iron in excessive amounts results in consumer complaints about: - Answer Turbidity The most important raw water constituent for a surface water plant is.... - Answer Turbidity Turbidity in water is cause by the presence of..... - Answer Suspended materials The main purpose of the jar test is to determine the best: - Answer Coagulant dosage The formation of chlorine ice affects chlorine feed rate. This can be prevented by: - Answer Decreasing the rate of chlorine withdrawal The fusible metal plug on a chlorine cylinder is designed to open at what temperature range? - Answer 157F-162F A lantern ring is a.... - Answer spacer ring in a pump packing gland When backwashing a filter, the backwash valve should be opened slowly to prevent.... - Answer Sand boils Suction lift refers to the pressure difference between the center line of the pump.... - Answer down to the hydraulic grade line Water Treatment Plant Operator Exam Questions With Answers Latest Updated 2024/2025 Graded A+ The parameter used to describe the roughness of the pipe interiors is called? - Answer C factor Prechlorination of raw water can lead to an interaction of chlorine with organic matter which can form? - Answer Trihalomethanes What is the main purpose of the coagulation and flocculation process? - Answer To remove turbidity What conditions most affect coagulation performance? - Answer Velocity, water temperature, detention time and coagulant dosage What would be the best indicator that the filter should be backwashed? - Answer Filter effluent turbidity The most crucial element of effective filter performance is... - Answer proper backwashing What is the chemical formula for calcium hypochlorite? - Answer Ca(OCI)2 A violation of the MCL for total trihalomethanes occurs when? - Answer The running average of quarterly samples during the previous 12 months exceeds the MCL. CT is defined as.... - Answer The product of residual disinfectant concentration and contact time of the disinfectant with the water. What would the pH of water be that had the highest concentration of hypochlorous acid? - Answer pH of 10, optimum range is pH of 5 What is the solution used to regenerate a zeolite softening unit? - Answer Sodium chloride solution or NaCL Langelier's index is used to determine - Answer Corrosiveness An effective chemical to raise pH is.... - Answer Caustic Soda AKA Sodium Hydroxide Minerals that cause an increase in alkalinity are? - Answer Calcium Carbonate and Magnesium Bicarbonate A problem related to ion exchange softeners is? - Answer Increase in sodium content Reservoir turnover is caused by... - Answer denser water at the surface sinking towards the bottom In a reservoir, the main water constituent that encourages algae growth is? - Answer Phosphorous A bubbler measures water level by sensing - Answer Air pressure The primary contaminant that is important to public health is? - Answer Bacteria What cannot be controlled in the normal operation of a sand filter? - Answer Influent turbidity A partial blockage on the intake line of a centrifugal pump may cause... - Answer Cavitation Continuous recording of the influent water turbidity is useful in indicating when to... - Answer change the alum dosage Which of the following would most likely improve the coagulation/flocculation process? - Answer Increase in water temperature What water treatment chemical is chemical feeder adjustment most critical because of potential toxicity? - Answer Sodium fluoride A chemical feed line that is installed after the sedimentation tank and before the filter is used to inject what chemical? - Answer Filter aid chemicals A dry chemical feeder is suitable for adding.... - Answer potassium permanganate Carbon dioxide is used in water treatment to do what? - Answer Lower pH pH meters should be standardized against.... - Answer a buffer solution with pH approaching that of the sample A Zeolite softening unit will replace calcium and magnesium ions with... - Answer sodium ions A liquid form of fluoride that is most widely used in water treatment is.... - Answer fluosilicic acid When alum is added to water, a floc is formed from the combination of alum and.... - Answer Alkalinity Successful performance of a sedimentation basin depends greatly upon... - Answer surface settling rate Potassium permanganate is a chemical most often used to... - Answer removed dissolved iron Recommended detention times for a sedimentation basin is... - Answer 2 hours Giardia lamblia may be removed from a surface water source by... - Answer Filtration What chemical would be most suited as a filter aid? - Answer Anionic polymer During backwashing, debris is noticed in the filter bed. What could that mean? - Answer Insufficient backwash rate Besides disinfection, what else is chlorine used for in water treatment? - Answer Taste and odor control The amount of the chlorine used by organic matter in water is a portion of the... - Answer chlorine demand Chlorine leaks in metal containers tend to... - Answer become larger The purpose of adding ammonia to potable water is to... - Answer form combined chlorine residual What would happen if a temporary fluoride feed rate increased to 62 mg/L in the finished water? - Answer Nausea and vomiting would occur in nearly all consumers It is important to maintain proper exhaust in areas where activated carbon is handled and fed to... - Answer prevent possible explosion Concentration of manganese in excess of 0.05 mg/L may result in... - Answer Turbidity The purpose of sodium thiosulfate in a microbiological sample bottle is to... - Answer remove chlorine residual that may be present What does not affect the friction loss in a water main? - Answer Water hardness Samples taken for routine analysis should be preserved by... - Answer refrigerating A method used to soften water is... - Answer ion exchange Pumps that work on the basis of inertia or mass moving in a circular motion are called... - Answer centrifugal The vent opening on an aerator should be screened with what size meshed screen? - Answer 24 Aeration in water treatment plants is used to... - Answer remove dissolved gasses Al2(SO4)3 is the formula for.... - Answer Aluminum sulfate Neglecting friction losses, a water line 6 inches in diameter can.... - Answer transport more water than two 4 inch lines Copper sulfate is used primarily to.... - Answer destroy algae Water high in sulfates can cause - Answer diarrhea Which laboratory test is concerned with indicator changes at pH 8.3 and about pH 4.5? - Answer Alkalinity Polyphosphates may be used in water treatment to... - Answer retard corrosion and calcium scale When operating a surface water plant, which laboratory tests are most significant for establishing dosages for coagulation? - Answer pH and alkalinity Alum added to turbid water containing alkalinity forms_____________, which increase in size and settle out. - Answer floc particles Specific conductance provides and estimate of.... - Answer dissolved solids Anabaena can cause what undesirable characteristic in water? - Answer taste and odor If polyphospahtes are used to sequester (suspend) iron, where is the best injection point? - Answer Before chlorination Which treatment step is not used with direct filtration? - Answer Sedimentation A watercourse that flows continuously at all times of the year is called? - Answer Perennial stream During the night, algae causes the pH of the water to? - Answer Decrease What contributes to the creation of algae blooms? - Answer Increased nutrients What is found mainly in groundwater sources and forms a precipitate when oxidized? - Answer Iron The Riparian Doctrine is sometimes called the? - Answer Rule of Reasonable Sharing The organisms used to indicate the likelihood that pathogenic bacteria may be present are? - Answer Coliform bacteria What adverse effects does the secondary contaminant manganese have? - Answer Discolored laundry and changed taste of water, coffee, tea and other beverages In general what causes an increase in taste and odors when natural waters lack dissolved oxygen? - Answer Anaerobic decomposition A physical property, as opposed to chemical property, important to water treatments is? - Answer Turbidity What are the two principal chemicals that cause water hardness? - Answer Calcium and Magnesium Free chlorine residual values are based on a contact time of at least.. - Answer 10 minutes What is the typical strength of calcium hypochlorite, i.e., available chlorine range? - Answer 65 to 70% The treatment process that controls corrosion or scaling is known as? - Answer Stabilization Permanganate reactions are highly dependent upon? - Answer pH Establishing an MCL for pathogenic organisms is not practical, because? - Answer No practical tests for their presence exist