Florida Class C Water Operator Exam (600 Questions) With 100% Correct Verified Answers | Exams Water and Wastewater Engineering | Docsity (2024)

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Florida Class C Water Operator Exam (600 Questions) With 100% Correct Verified Answers What is an Ampere? - a unit of measurement for current Which of the following is a type of pump that is commonly used in a water treatment plant? - Centrifugal What is a multi-staged pump? - has more than one impeller if the pump impeller is running backwards, what action must be taken to correct the rotation? - switch any two electrical leads When should the packing of a pump be adjusted? - when the pump is running when a pump fails to deliver at its rated capacity, what is most likely the cause? - air leak what is a common cause for vibrations in a motor? - misalignment of the couplings What is the purpose of the wear rings in a pump? - Plug internal leakage what should the seal water pressure be for a pump? - 5 psi higher than the pumps discharge pressure what is the purpose of the seal water? - block out air intake and lubricate the packing what is the recommended maximum suction lift? - 15 ft. In a water treatment plant, what type of pump is commonly used to deliver chemical solutions? - Positive displacement when should you lubricate your equipment? - follow the manufacturer's recommendations In what manner is packing installed? - a strip at a time and staggered a positive displacement pump should never be operated________? - against a closed discharge valve if two of more pumps of the same size and purpose are online, what method of operation is recommended for them? - alternate to equalize wear If half of the mechanical seal fails, what corrective action should be taken? - change both halves of the seal what is the purpose of a lantern ring? - water seal The packing of a pump should be adjusted to _________? - allow a slight operating leakage and allow approximately a drip per second. On a multiple drive motor, when a belt fails, what corrective action should be taken? - Replace all the belts on the drive To keep a centrifugal pump primed, install a _______ valve at the end of the suction line. - foot valve If a motor fails to start, what should be checked first? - Power supply Opening or closing a valve rapidly will cause? - water hammer The formation and collapse of a gas pocket or bubble on the blade of an impeller is called? - cavitaion Changing the packing on a pump is called ________ maintenance - corrective what is an example of a daily maintenance task for a compressor? - drain the air receiver what type of valve is usually used to control the rate of flow? - globe valve what type of valve is buried? - non-rising stem what is the most common valve type used in a water treatment plant? - gate valve what will happen if the gate valve is left half open to control flow? - Undue seat wear In what manner should carbon be stored? - on concrete floor in single rows what is brinelling? - a type of bearing wear what is the recommended manner for storing potassium permanganate? - on a concrete floor away from heat or heated pipes what causes more damage to a pump's impeller? - Air What is the unit of electrical resistance? - Ohm What is an ammeter - measures amps and current what type of electrical service is usually found in water plants? - three phase what test can measure total and fecal coliform at the same time? - Colilert an organism found in the intestines of human beings and animals, and in plants, land, and air is called? - Coliform An organism found only in the intestines of warm blooded animals is called? - fecal coliform the best test to measure the effectiveness of a WTP's process is? - turbidity the number of monthly samples for coliform analysis is based on? - population served when 40 or more coliform samples are taken, you can have_____ positive - 2, or 5% at the extremes of the distribution system you must have at least a ____ free CL2 residual. - 0.2 E-coli broth is used when testing for____. - fecal coliform chlorine should never be fed ahead of ___? - polyphosphates the distribution system has complaints of pink water. The WTP has a greensand filter. What is most likely the cause? - overdose of potassium permanganate the addition of chlorine to water until the demand is satisfied and every drop of water after that is free residual is called? - break point chlorination adding alum to water _____ the PH level. - lowers a common membrane used in reverse osmosis water treatment is____. - cellulose acetate all surface water and ground water under the influence of surface water must be _______. - disinfected and filtered. to obtain a "C" water license, an operator must have ________ hours of on the job training. - 2,080 what is the action level for lead? - 0.015 mg/l what is the maximum chlorine residual level allowed in the distribution system? - 4.0 mg/l for water systems using chlorine dioxide, what is the MCL for chlorite? - 1.0 mg/l what is the MCL for color? - 15 the MCL for turbidity is not more than ____ NTU as a monthly average - 0.5 the WTP uses 360 gallons of 10% NaOCl a day. how many pounds of CL2 do they use? - 300 are you going to pass this test? - Yes you are! the WTP totalizer read 0129 at the beginning of the first shift for the month and 0000 at the end of the last shift for the month. How many gallons of water were treated daily? - 0.329 MGD what is the marble test used for? - determine if water is scale forming or corrosive using the membrane filtration method, what is the incubation temperature for the total coliform test? - 35.0 degrees C. plus or minus 0.5 degrees C for the membrane filtration method, what is the incubation period for total coliform? - 24 hrs + or - 2 hrs with the membrane filtration method, what is the incubation time for the fecal coliform test? - 24 hrs + or - 2 hrs what is the molecular weight of Na2CO3? (N=23, C=12, O=16) - 106 who had a better career? Kobe or Tim Duncan - Tim Duncan What is Texas Independence Day? - March 2nd, 1836 what are the criteria used to classify water treatment plants? - size and process used when NaOCl is added to water, what reaction takes place? - PH increases what happens when HOCL is added to water? - PH decreases what is a common level control device used in water treatment plants? - ball floats a water system that has at least 15 service connections used by all year residents or regularly serves at least 25 year round residents is called? - community system a system that has at least 15 service connections, or regularly serves an average of at least 25 individuals daily at least 06 days out of the year is a ______ system? - public the chief operator for a class "B" WTP needs what level of license? - B a "B" class WTP must have a "C" operator or higher on duty for ______. - 16 hrs a day / 7 days a week what is the most effective PH range for iron removal? - 8 to 9 a successful method for removing H2S from water with a Ph of 9.4 is to ? - increase aeration adding sodium aluminate to water will? - increase PH what is the lowest hardness achievable by the lime or lime-soda ash process? - 30-40 when you are gathering the monthly coliform samples, what other test/sample must be taken? - chlorine residual a natural underground layer of porous, water-bearing materials usually capable of yielding a large supply of water is called? - an aquifer what is the most likely cause of black water in the distribution system? - manganese and H2S specific conductance is an indirect measurement of ________? - TDS what is the purpose of installing tube settlers? - aid sedimentation how long does the coagulation process take? - a few seconds during an inspection of the plant, you discover that a filter is air-bound. what action should you take? - backwash the filter immediately. what will affect the efficiency of tube settlers? - high wind how many zones are the in a sedimentation basin? - 4 Aluminum sulfate is used as a coagulant because it has? - trivalent ions the zeta potential and size of particles in water affect the? - settling in the coagulation and flocculation process, the difference in the electrical charge between the dense layer of ions surrounding the particle and the charge of the bulk of the suspended fluid surrounding the particle is called? - zeta potential the particles in water generally have a _____ charge. - negative what is the turnover of a lake due to the equalization of temperatures throughout the layers called? - destratification the portion of a body of water that extends from shoreline to the limit of growth of rooted plants called? - littoral what are reservoirs or lakes that are rich in nutrients called? - Eutrophic what method of treatment will remove a fishy odor from the water? - chlorination The development of vertical mixing within the lake or reservoir to eliminate separate layers of temperature, plant, or animal life is called? - destratification the minimum odor of a water sample that can just be detected after successive dilutions with odorless water is the ___________. - TON (threshold odor number) the addition of chlorine to water that has a medical odor to it will_________. - intensify the odor. reservoirs and lakes that are nutrient poor, containing little or no plant or aquatic life are called? - Oligotrophic what happens to the water during daylight hours when there is an algal bloom? - PH increases when algae die off, bacteria that feed upon the algae use oxygen and can cause_______ that may result in fish kill. - oxygen depletion a process in which organisms with the aid of chlorophyll, convert carbon dioxide and inorganic substances into oxygen and additional plant material, using sunlight for energy is known as? - photosynthesis what is the difference between organic and inorganic matter? - carbon what chemical is used to control algal blooms? - bluestone what may interfere with the efficiency of copper sulfate? - Alkalinity what type of device is used when drawing water from a surface water source? - a single or multi-level intake structure good floc is observed forming in the flocculation basin. The size increases the later breaks up. What is likely the cause? - floc mixer RPM too high during a plant tour, a lot of floc is observed flowing over the laundering weirs. what is the probable cause? - Floc too light for detention time in a jar test, the floc starts to settle before the mixers are topped. what does this indicate? - overdose if you're happy and you know it, clap your? - hands what type of floc should form during coagulation? - discrete and fairly dense you observe small and well dispersed floc entering the flocculation basin. what does this indicate? - effective coagulation in a jar test, what does it mean after the mixers are stopped and 80% of the floc has settled within 15 minutes? - good settling and test results water in the treatment unit has a milky of blueish tint. what is the probable cause? - overdose of alum The best coagulant dosage is one that produces finished water that meets drinking water standards and ______. - produces the least amount of sludge / fastest settling what is a problem associated with disposal of alum sludge? - hardens soil when troubleshooting plant processes, you should ? - make only one change at a time what method is used to determine the correct coagulant dosage? - jar test what is tapered energy mixing? - reducing speed of floc mixers where is a filter aid coagulant applied? - filter influent what type of polymer id usually used as a filter aid? - nonionic what are the 4 zones in a sedimentation basin? - inlet, outlet, settling, sludge the information gathered from a jar test is only relevant if the results are _______ and ________. - applied and verified during the winter months, you notice the floc forms and settles slower. what is most likely the cause? - lower temperatures "Party on, Wayne." "Party on, _______"? - Garth in enhanced coagulating process, where is the acid added? - prior to coagulation what is the most effective PH range for alum? - 5-7 coagulation is ________ and chemical reaction between the ______ of the water and the coagulant. - physical, alkalinity what is an advantage of returning sludge slurry in a contact unit? - lowers chemical costs In the V/V test, a _____ ml sample is taken from the _____ zone and allowed to settle for ____? - 100, reaction, 5 minutes in the direct filtration process, what step is omitted? - sedimentation the release of dissolved oxygen in saturated cold water sue to decrease in pressure may cause what problem in the filter? - air binding operation a filter continuously with high head loss will cause? - air binding what causes mudball formation in the filter? - improper backwashing how much wood could a wood chuck chuck if a wood chuck could chuck wood? - 21 what is the fourth step in the backwash procedure? - start surface scour what parameters are used to determine filter backwash time? - head loss, turbidity, time what is the filtration rate for a slow sand filter? - 0.015 to 015 gpm/sq ft what causes media boils? - high backwash rates what are the most important particle removal mechanisms in filtration? - sedimentation and adsorption if a filter has a design head loss of 8 feet, and the initial head loss is 1.5 ft, at what head loss should you backwash the filter? - 6 feet if a 16 sq. ft. filter has a flow of 6 MGD, what is the filtration rate? - 26 gpm / sq foot Why is a space left in the twirl bag when sampling coliform? - To allow for mixing what is the reason for adding sodium thiosulfate to the twirl bag? - remove chlorine what is the MCL for coliform? - Presence or absence how soon after sampling must the coliform test be taken? - 6 hours a green haired superhero, whos mission was to save the planet from pollution. He could be summoned by his teenage friends with magical rings. - Who is Captain Planet? what is measured when you titrate a liquid with .02 N Sulfuric Acid to a PH of 4.5? - total alkalinity what is the ring shaped space located between two circular objects called? - annular space what is used to measure the smoothness of the interior of a pipe? - C factor the _____ the C factor, the _______ the interior of the pipe. - higher, smoother an electrical system installed as protection against corrosion is called? - cathodic protection a substance composed of two or more elements whose composition is constant is called? - a compound corrosion caused by connection two dissimilar metals is called? - galvanic the decomposition of material by chemical or electrochemical reaction is called? - corrosion a steel specimen inserted into water to measure the water's corrosiveness is called? - coupon what chemical is used to detect a sulfur dioxide leak? - ammonia if the water has a sweet, aromatic odor, what may be used to eliminate the odor? - GAC the exposure to certain odors over a period of time can cause? - Olfactory fatigue secondary drinking water regulations deal with _____. - aesthetics primary drinking water regulations deal with which of the following? - health concerns what will add longevity to a WTP equipment? - preventative maintenance the identification of each source of energy and rating them by load size and prioritizing them to indicate their importance in the overall operational program is called? - power management the decomposition of a material by an outside current is called? - electrolysis the common boundary between two substances is called? - interface what is used to express the basic or acidic condition of water? - PH what is a sample portion of water that is nearly identical in content and consistency as possible to that in the larger body of water called? - representative the development of small mounds of corrosion products inside iron pipe is called? - tuberculation what is the electrical pressure available to cause a flow of current when the electric circuit is closed known as? - electromotive force water with high TDS, low PH, high temperature, and low softness is? - corrosive what is the single most corrosive component of water? - oxygen what caused red water? - iron bacteria what are crenothrix? - iron bacteria what substances in water can cause cancer? - carcinogens what are disease causing substances called? - pathogens what type of corrosion is found in copper pipes? - erosion corrosion during a marble test, adding the calcium hydroxide caused the PH , alkalinity, and hardness to increase. What does this indicate? - water was undersaturated in membrane softening, what chemical is usually added to raise the PH? - caustic soda when water is stored in open reservoirs, adding zinc phosphate may cause what condition? - algal bloom first draw samples taken from the customers' kitchens are analyzed for what substances? - lead and copper a water system is required to initiate a public information program and/or initiate adding phosphate to the water and/or make alkalinity or PH adjustments when it? - exceeds lead action level a sample taken from a customer's tap that has not been used for a minimum of 6 hours or a maximum of 12 hours is called? - first draw what is the action level fro copper? - 1.3 mg/l after adding calcium carbonate to a water sample during the marble test, the PH, alkalinity, and hardness go down. what does this indicate? - water was supersaturated what happens in hot water heaters when the water is saturated with calcium carnonate? - calcium carbonate precipitates from the water water with a negative langlier index will cause? - corrosion what type off corrosion is caused by a source that originates outside the plumbing or water system? - stray current how often is a water system serving more than 10,000 people required to sample for THM? - quarterly what is the minimum number of samples to be taken during the THM sample period? - 1 what is the minimum amount of sample that is required to test for THM? - 25 ml when drawing a sample for THM, you notice a bubble in the sample jar. what should you do? - keep adding water until the bubble leaves the jar how long can a THM sample be held before analysis? - 14 days how are THMs reported on the MOR? - running average the THM sample jar contains sodium thiosulfate. what will you test for ? - total THM what is a common ion exchange media? - zeolite a type of backflow caused by negative pressure is called? - backsiphonage how long can iron samples be held before being analyzed? - 48 hrs what is the most accurate method to test for iron and manganese? - atomic absorption what chemical when added to water will delay the precipitation of iron and manganese? - polyphosphate why is nitric acid added to samples collected for iron and manganese analysis? - lowers PH and keeps metals in solution what is the longest running production sports car? - corvette (1954) a filter has a sudden increase in head loss. Media surface sealing is suspected. what action should be taken? - evaluate plant process, jar test if needed when chlorine is added to water, it is a more efficient disinfectant when the PH is lower and a greater percentage of ______ is present. - HOCL the term flash mix is associated with which of the following processes? - coagulation disinfection is best accomplished when what conditions exist? - high concentration and long contact time you are working with a solution with a 15% chemical strength. How many pounds of chemical are in this solution? - 1.25 the plant flow is 7.5 MGD. The treatment unit is 70' long, 20' wide, and 10' deep. what is the detention time in minutes? - 34 minutes five pounds of HTH are added to 100 gallons of water for disinfection. 80 gal. of the solution were used. How many pounds of chlorine were actually used? - 2.6 what NBA player was a Defensive Player of the Year and the league leader in scoring in the same season? - MJ what NFL running back has the most rushing yards all time? - Emmitt Smith? taste and odor problems required super chlorination in plant. how would you dechlorinate before sending the water to distribution? - GAC which of these terms best describes electrolysis? - stray current convert 250 mg/l of total hardness to grains per gallon - 15 convert 35 gpg to mg/l of total hardness - 599 the pressure gauge on the chlorine feed reads 90s and the injector gauge reads 10s. The chlorine residual keeps dropping. what is most likely the cause? - restriction in supply line what color is concrete? - grey when installing a pipe fitting that will change direction of flow. what is the proper installation method? - thrust block how long must water plant operation records be kept on site? - 10 years what is usually indicated when at sample point "A" in a water main a high DO reading is obtained, and at sample point "B" downstream, the DO reading is substantially lower? - corrosion when is THM formation more likely to occur? - spring and fall with what material is hydrochloric acid highly reactive? - metals sand drying beds are similar in construction to ? - gravity sand filters calculate the langlier index where the PH = 8.8, and the PHs is 8.3 - +0.5 a positive langlier index is _______. - scale forming what do we call a detailed description of all underground features discovered during well drilling? - geological log what information is need to calculate the PHs for the langlier index? - temp, TDS, Alkalinity, Calcium hardness what process is commonly used to remove volatile organics from water? - polyphosphates how often must a water system test for radionuclides? - 3 yrs calculate the amount of water needed to backwash a 360 sq ft dilter at 9000 gpm. the backwash duration is 8 minutes. - 72,000 gal in January a 6 ppm Cl2 dosage produced a 2.0 ppm residual. In July an 8 ppm dosage produced a 1.5 ppm residual. what is most likely the cause for the lower chlorine residual? - increase in water temperature why is recarbonation necessary when lime softening is used to reduce excessive hydroxide hardness? - reduce the scale forming tendencies of the supersaturated H2O In hot water systems, scaling is a problem because _________ is less soluble in hot H2O than it is in cold H2O. - calcium carbonate what is the primary purpose of filters in a WTP? - lower turbidity a WTP meets or exceeds all treatment parameters. It has started to receive customer complaints concerning red water in the distribution system. Polyphosphate is being used in the treatment process. what is most likely causing the red water? - polyphosphate reverted to orthophosphate a well pump is rated at 6000 gpm at 85% efficiency. the well is 15' long, 12' wide, and 10' deep. if the pump takes 10 minutes to lower the well 5 feet, does it pump higher or lower than rated? - 73 gpm, higher what will happen if the recirculation rate for a solid contact unit is too high? - overflow of slurry to filter if a water sample tests positive for coliform, what action must be taken by the water system? - repeat sample 24 hours after notification Many samples for MCL compliance are taken in the distribution system. what sample is taken where the water enters the distribution system? - turbidity when taking a hardness test, the titration should be completed within 5 min. An inhibitor reagent should be used when metal ion interference causes an indistinct end point, and _________. - a sample volume should be selected which requires less than 15 ml of EDTA titrant. to control THM formation, alternate disinfectants are used including ozone, chlorine dioxide, and _______. - chloramines. to insure membrane longevity and slow down hydrolysis, RO plants add _____? - acid the recovery rate of a membrane softening plant is limited by what two factors? - desired product h2o quality and mineral content media loss is caused by high backwash rate and air bubbles caused by? - air binding when alum dosage is decreased, lime dosage may? - decrease what will happen if the brine valve in an RO unit is fully closed? - 100% recovery and damage to the membranes the plant operator is having difficulty maintaining the sludge blanked in the solids contact unit. what action is needed? - adjust recirculation rate how often must the standby generator be operated? - 4hrs continuously under load, once a month the sludge blanket is too low. what should you do to raise the blanket level? - reduce blowoff times or duration. a lime softening plant is having trouble with slow floc formation. what is the most cost effective way to solve the problem? - recycle settled sludge which of the following conditions will lead to a smaller number of THMs forming? - low PH a surface WTP has a medicinal taste in its finished water. What is the most likely cause? - Phenols Volatile organics are commonly removed by? - degasification a chlorinator is experiencing low chlorine feed rate with the rate valve open. the injector vacuum is low but increases when the rate valve is shut. what is the probable cause? - clogged injector and insufficient injector water supply high concentration of hypochlorus acid is found in water with a PH of? - 6.6 ( Low PH ) a WTP using the lime softening process has a finished water hardness of 83 mg/l and a +).5 L.I. . What does this indicate? - finished water is scale forming the oxidation of iron to form insoluble ferric hydroxide can be increased by? - higher water Ph In a lime softening plant, what is the ideal stoichiometric relationship for alkalinity? - 2P what is the first step taken to determine the cause of a taste or odor problem in the distribution system? - Locate point of origin in the distribution system which of the following methods is used to determine the optimum coagulant dosage? - jar test lower temperatures in the treatment unit can causes? - floc carryover which of the following is considered a water-borne disease? - cholera what is a common cause of temporary cloudiness in a water sample taken from the kitchen? - air generally, the detention time in a conventional sedimentation basin is? - 2 - 6 hours water with high amounts of DO is? - corrosive a WTP using 10%sodium hypochlorite solution switches to a 5% solution. what change must they make to insure adequate disinfection? - increase dosage by 100% to remove magnesium hydroxide, a WTP is using excess lime and recarbonation. What method can you recommend to lower their treatment costs and maintain the water quality? - split treatment a treatment plant using greensand filtration is receiving complaints of red water. What can you recommend to resolve the problem? - regenerate the greensand with potassium permanganate In membrane softening, concentration polarization leads to an increasing tendency for precipitation of sparingly soluble salts and? - deposition of particulate matter on the membrane which of the following can be used to increase the recovery rate of an RO plant? - increase operating pressure groundwater systems using free chlorine as a disinfectant are required to provide a minimum of _____ minutes contact time as _____ flows. - 15 / peak hourly the solution feeder has a maximum output of 30 GPH. the rate control scale reads in percentage. what should the feeder be set at to feed 10 GPH? - 33 % Express 20 degrees Celsius in Fahrenheit. - 68 pumping from a well at a rate exceeding the rate of replacement leads to what condition? - aquifer depletion a vent on the well casing allows? - entrance or escape of air / gas in order to prevent damage from water hammer, hydropneumatic tanks should have? - pressure relief valves. an RO plant produces 0.88 MGD with a feed flow of 740 GPM. what is the percent recovery? - 83% what is the probable source of gasoline or chemical taste and odor complaints? - chemical spill why is sodium thiosulfate added to a coliform sample bag? - remove chlorine how long can samples be held before testing for chlorine residual? - immediately who is responsible for plant operations regardless of the size or process method? - licensed operator what information is needed to determine the amount of alkalinity to add for proper coagulation? - alkalinity of raw water when a well has been cleaned and pumped until all traces of disinfectant are gone, bacteriological samples must be taken for how many consecutive days? - 20 to prepare a coagulant at the WTP, 9.5004 grams of chemical is diluted in 1000ml of water. the WTP has only 6.2004 grams of the chemical available now. how many ml of distilled water must be added to the 6.2004 g to obtain the same solution strength? - 653 ml when must a WTP submit the results of fluoride split analysis sampling to the HRS state dental office? - monthly how many grams per liter of NaOCL are in a 0.20 N solution? N= 23 O = 16 Cl = 35.5 - 14.9 what is the maximum holding time for turbidity samples? - 48 hrs when collecting iron samples, what chemical is added as a preservative? - HNO3 to Ph < 2 physical factors that affect coagulation include? - Ph, alkalinity, temperature, turbidity while the filter influent valve is shut, the water level in the filter drops 6" in 90 seconds. The filter is 12' long and 8' wide. what is the filtration rate in gpm/sq ft? - 2.5 when dealing with disciplinary situations, a supervisor should be? - calm, flexible, and open minded a community water system serving 350 or more persons, or having 150 or more service connections must provide auxiliary power for operation of source treatment units and pumps at a rate equal to? - average daily flow. how many pounds of dry polymer must be added to a 10 gal tank to produce a .30 strength solution? - 2.5 lbs How many gallons of water must be added to a fallon of 6% NaOCl solution to produce a .06% solution? - 99 gal the V/V test indicates 2% sludge. what change should you make in plant process? - blow off less sludge what was the best starwars movie? - all answers are acceptable except episode 1 what is the best way to control chemical dosages in a treatment plant? - electronically controlled chemical feeders which of the following is a physical characteristic of water? - color what is the most likely source of water with a hardness of 200 - 300 mg/l as CaCO3? - groundwater from an area which has a soluble limestone geology what is the disadvantage of removing non-carbonate hardness? - sodium content in water is increased By ________ the speed of the recirculation device, in an up flow solids contact unit, a _____ amount of slurry can be retained in the unit. - Increasing / larger what is the highest possible turbidity reduction expected when operating a filtration process under optimum conditions? - 99.5% which of the following conditions are conducive to triggering algal blooms? - abundant sunlight and nutrients like nitrogen and phosphorous. the funnel shaped volume within the radius of influence is called the _____. and for an aquifer this represents that part of the aquifer, which is being dewtered. - cone of depression which of the following is a disadvantage of the cascade type aerators? - encourages biological growth. which of the following conditions would not be a cause for a pump's electric motor to fail to start? - pump not connected to motor before starting any water lubricated pump, an operator should make sure that______ - bearings are wet a hypochlorite solution is being prepared in a 100 gal tank. if you add 20 gal of 5% NaOCL to the tank, how much water should be add to the tank to get 1.5% hypochlorite solution? - 47 gal what is the average velocity in an 8" pipe if the flow is 500 GPM? - 3.18 ft/sec well water with an iron concentration of 2.45 mg/l is aerated. After aeration the iron concentration is 0.35 mg/l and the manganese concentration is 0.60 mg/l. Calculate the KMnO4 dosage needed to remove the iron and manganese. - 1.27 mg/l the iron exchange unit is treating 2.0 MGD with a hardness of 225 mg/l. The desired finished water hardness is 6.0 gpg. How many gallons must be bypassed? - 0.923 MGD what is the static water level of a well? - the level when the water isn't being pumped what factor is considered when determining the required capacity of distribution system mains? - number of service connections a well with a caisson that is sunk into the aquifer, with horizontal wells drilled into the aquifer from the bottom of the caisson is called? - a radial well which of the following is a source of lead in drinking water? - galvanized pipe water supplies with high levels of ____ may produce laxative effects. - sulfates RP membrane fouling can be caused by ? - bacteria in January, a WTP is having trouble feeding CL2. The CL2 building is heated, but the lines going to the CL2 point are not heated. What is causing the problem? - condensation in line when must the MOR's be submitted to FDEP? - within 10 days after the month of operation when sludge is allowed to accumulate too long in a solids contact unit, ______ is decreased. - detention time WTPs using solids contact units require? - tighter process control and less space to accomplish treatment controlling organic loading and taste and odor problems within a reservoir may reduce or eliminate? - activated carbon treatment THM precursors are? - naturally occurring organic compounds the variable vacuum control on the chlorinator won't feed at a maximum rate. Gas pressure and CPRV are good. what is the problem? - plugged restrictor when treating very cold water, what change must be considered? - increase coagulation dose one of the first warnings a water system has a possible cross connection contamination is a complaint of a water taste or odor that is? - septic or musky the finished water from an ion exchange unit has a salty taste to it. what is the likely cause? - the rinse stage was not successful. in a properly operating ion exchange system, the finished water_______. - is free of calcium and magnesium the indicators used in the alkalinity titration, change color according to changes in? - Ph iron and manganese react with _____ to form insoluble compounds. - chlorine when using aeration, the rate of iron oxidation to form insoluble ferric hydroxide can be increased by? - raising Ph the same ion exchange resins that are used to soften water can be used to remove iron and manganese if the water being treated? - contains no dissolved oxygen what test uses lactose fermentation to demonstrate the presence of absence of coliform? - presumptive which chemical must be present in the sterile sample container used to collect samples for coliform analysis? - sodium thiosulfate if 3.5 ml of titrant are used to reach the total alkalinity end point for a 100ml sample, what is the total alkalinity? - 35 the water has a marshy or woody odor. what is likely the cause? - actinomycetes velocity sensing devices measure flow by sensing? - rate of rotation apparent color is removed by? - filtration true color is usually removed by? - coagulation which standards regulate the amount of fluoride in water? - primary and secondary standards what is the chemical name for caustic? - sodium hydroxide (Na OH) what is the chemical name for liquid bleach? - sodium hypochlorite (Na O Cl) when making a determination on water production for a specific day, the amount treated compared to the previous day may be decreased if? - temperature decreases a shorthand name for a chemical element is? - chemical symbol