Rectangular Basin = Volume, gal (Length, ft) x (Width, ft) x (Height, ft) x7.48 gal/cu.ft.

Units and Conversion Factors 1 cubic foot of water weighs 62.3832 lb 1 gallon of water weighs 8.34 lb 1 liter of water weighs 1,000 gm 1 mg/l = 1 part per million (ppm) 1% = 10,000 ppm ft 2 = square feet and ft 3 = cubic feet 1 mile = 5,280 feet (ft) 1 yd 3 = 27ft 3 and 1 yard = 3 feet 1 acre (a) = 43,560 square feet (ft 2 ) 1 acre foot = 325,829 gallons 1 cubic foot (ft 3 ) = 7.48 gallons (gal) 1 gal = 3.785 liters (L) 1 L = 1,000 milliliters (ml) 1 pound (lb) = 454 grams (gm) 1 lb = 7,000 grains (gr) 1 grain per gallon (gpg) = 17.1 mg/l 1 gm = 1,000 milligrams (mg) 1 day = 24 hr = 1,440 min = 86,400 sec 1,000,000 gal/day 86,400 sec/day 7.48 gal/cu ft = 1.55 cu ft/sec/mgd CHLORINATION STATE OF CALIFORNIA DEPARTMENT OF PUBLIC HEALTH DRINKING WATER OPERATOR CERTIFICATION PROGRAM Dosage, mg/l = (Demand, mg/l) + (Residual, mg/l) (Gas) lbs = Vol, MG x ppm or mg/l x 8.34 lbs/gal HTH Solid (lbs) = (Vol, MG) x (ppm or mg/l) x 8.34 lbs/gal ( % Strength / 100 ) Liquid (gal) = (Vol, MG) x (ppm or mg/l) x 8.34 lbs/gal ( % Strength /100) x Chemical Wt. (lbs/gal) VOLUME Rectangular Basin = Volume, gal (Length, ft) x (Width, ft) x (Height, ft) x7.48 gal/cu.ft. Cylinder, Volume, gal = (0.785) x (Dia, ft) 2 x (Height, Depth, or Length in ft.) x 7.48 gal/ft 3 Time, Hrs. = ( Volume, gallons ) (Pumping Rate, GPM, x 60 Min/Hr ) Supply, Hrs.= Storage Volume, Gals d ( Flow In, GPM Flow Out, GPM) x 60 min/hr.) SOLUTIONS Lbs/Gal = (Solution %)_ x 8. 34 lbs/gal x Specific Gravity 100 Lbs Chemical = Specific Gravity x 8.34 lbs/gallons x Solution(gal) Specific Gravity = Chemical Wt. (lbs/gal) 8. 34 (lbs/gal) % of Chemical = ( Dry Chemical, Lbs) x 100 in Solution (Dry Wt. Chemical, Lbs) + (Water, Lbs) GPD = (MGD) x (ppm or mg/l) x 8.34 lbs/gal ( % purity ) x Chemical Wt. (lbs/gal) GPD = ( Feed, ml/min. x 1,440 min/day ) ( 1,000 ml/l x 3.785 L/Gal ) PUMPING 1 horsepower (Hp) = 746 watts = 0.746 kw = 3,960 gal/min/ft Water Hp = ( GPM ) x ( Total Head, ft ) (3,960 gal/min/ft) Brake Hp = ( GPM ) x ( Total Head, ft ) ( 3,960 ) x (Pump % Efficiency ) Motor Hp = ( GPM ) x ( Total Head, ft ) ( 3,960 ) x Pump % Eff. x Motor % Eff. Wire to Water Efficiency = ( Motor, % Efficiency x Pump % Efficiency ) Cost, $ = ( Hp ) x ( 0.746 Kw/Hp ) x ( Operating Hrs. ) x cents/kw-hr Flow, velocity, area Q = A x V Quantity = Area x Velocity Flow (ft 3 /sec) = Area(ft 2 ) x Velocity (ft/sec) MGD x 1.55 cu ft/sec/mgd = cu ft/sec = ft/sec.785 x pipe diameter ft x pipe diameter ft = sq ft General ($) Cost / day = Lbs/day x ($) Cost/lb Removal, Percent = (In - Out ) x 100 In Specific Capacity, GPM/ft. = Well Yield, GPM Drawdown, ft. Gals/Day = (Population) x (Gals/Capita/Day) GPD = (Meter Read 2 - Meter Read 1) (Number of Days) Volume, Gals = GPM x Time, minutes PRESSURE PSI = ( Head, ft. ) PSI = Head, ft. x 0. 433 PSI/ft. 2.31ft./psi lbs Force = (0.785) ( D, ft. ) 2 x 144 in 2 /ft 2 PSI. Two Normal Equations: a) C 1 V 1 = C 2 V 2 Q 1 = Q 2 V 1 V 2 b) C 1 V 1 + C 2 V 2 = C 3 V 3 C = Concentration, V = Volume, Q = Flow SCADA = 4 ma to 20 ma analog signal ( live signal ma - 4 ma off set ) x process unit and range ( 16 ma span ) 4 ma = 0 20 ma full -range

FILTRATION Filtration Rate (GPM/sq.ft) = Filter Production (gallons per day) sq. ft. = square feet (Filter area sq. ft.) x (1,440 min/day) Loading Rate (GPM/ sq. ft.) = ( Flow Rate, GPM ) ( Filter Area, sq. ft. ) Daily Filter Production (GPD) = (Filter Area, sq. ft.)x (GPM/ sq. ft. x 1,440 min/day) Backwash Pumping Rate (GPM) = (Filter Area, sq. ft.) x (Backwash Rate, GPM/ sq. ft.) Backwash Volume (Gallons) Backwash Rate, GPM/ sq. ft. = (Filter Area, sq. ft. ) x (Backwash Rate, gpm/ sq. ft. ) x (Time, min). = ( Backwash Volume, gallons) ( Filter Area, sq. ft.) x (Time, min) Rate of Rise (inches per min.) = (backwash rate gpm/sq.ft.) x 12 inches /ft 7.48 gal/cu.ft. Unit Filter Run Volume, (UFRV) = (gallons produced in a filter run) (filter area sq. ft.) C T CALCULATIONS C t = (Chlorine Residual, mg/l)x(time, minutes) Time, minutes = ( C t ) ( Chlorine Residual, mg/l ) Chlorine Residual (mg/l) = ( C t ) ( Time, minutes ) Inactivation Ratio = ( Actual System C t ) ( Table E C t ) C t Calculated = T 10 Value, minutes x Chlorine Residual, mg/l Log Removal = 1.0 - % Removal x Log key x ( -1 ) 100 SEDIMENTATION Surface Loading Rate, (GPD/ sq. ft.) = ( Total Flow, GPD ) ( Surface Area, sq.ft.) Chemical Dosage Calculations Note (% purity) and (% commercial purity) used in decimal form Lbs/day gas feed dry = MGD x (ppm or mg/l) x 8.34 lbs/gal Detention Time = Volume flow Lbs/day = MGD x (ppm or mg/l) x 8.34 lbs/gal % purity Detention Time hours = volume (cu ft) x 7.48 gal/cu ft x 24 hr/day Gal/day GPD = MGD x (ppm or mg/l) x 8.34 lbs/gal (% purity) x lbs/gal Flow Rate = Volume Time GPD = MGD x (ppm or mg/l) x 8.34 lbs/gal (commercial purity %) x (ion purity %) x (lbs/gal) Weir Overflow Rate, GPD/L.F. = ( Flow, GPD) ( Weir length, ft. ) ppm or mg/l = lbs/day or gallons x % purity x lbs/gal MGD x 8.34 lbs/gal MG x 8.34 lbs/gal

Water Treatment Math Worksheet 2015 1. If a water treatment plant was disinfecting their water storage tank holding 1.2 MG of water with a dose of 4 ppm of chlorine gas, how many pounds of chlorine would be needed? Answer 40 lbs 2. If a water treatment intake was pumping 2,000,000 gal/day though a 12 inch pipe, what is the velocity of water through this pipe in ft/sec? Answer 3.936 ft/sec 3. What is the filtration rate in gpm/sq ft through a sand filter unit measuring 20 feet wide by 40 feet long if the daily flow through the filter were 1,500,000 gal/day? Answer 1.3 gpm/sq ft 4. What is the detention time in hours through a sedimentation basin measuring 40 feet wide, 60 feet long and 20 feet deep if the daily flow is 950,000 gal/day? Answer 9 hr 5. How many pounds of chlorine gas would be used each day if the flow of 2,300,000 gallons per day were dosed with 6 mg/l of chlorine gas? Answer 115 lb/day 6. If a storage tank measured 50 feet in diameter and held 42 feet of water, how many pounds of 70% calcium hypochlorite would be needed to dose this tank at 4 ppm? Answer 29 pounds 7. If a treatment plant were using 10 ml/min of aluminum sulphate (alum) to treat their water, how many gallons per day of alum is being used? Answer 3.8 gal/day 8. How many gallons of 1.1 SG, 5.25% bleach would be used to treat a storage tank holding 150,000 gallons if the desired dose was 5 mg/l? Answer 12.7 gal 9. What is the detention time in hours for a sedimentation basin measuring 60 feet in diameter and 30 feet tall if the flow is 694 gallons per minute? Answer 15.2 hours 10. How many gallons of water are left in a reservoir if there were 10 acre feet of water at the beginning of the month and 1,000,000 gallons were removed by the end of the month? Answer 7 acre feet 11. If a water treatment plant were using 12.5% sodium hypochlorite weighing 9 lbs/gal to disinfect a flow of 1,200,000 gallons per day with a dose of 4 ppm, how many gallons would be needed daily? Answer 35.5 gal 12. If the chlorine demand for a water source was 2 mg/l and the chlorine residual was 1.5, what is the chlorine dose? Answer 3.5 mg/l 13. If a water storage tank held 1.3 MG of water and an operator decided to add a 3 mg/l dose of chlorine to the tank, how many pounds of chlorine gas would be needed? Answer 32.5 lbs 14. If an operator decided to use 70% HTH to disinfect a 900,000 gallon storage tank at a dose of 4 mg/l, how many pounds of HTH would it take? Answer 42.89 lbs 1

15. How many gallons of 5.25% bleach would it take to disinfect a 1.2 MG storage tank if the desired dose was 6 mg/l? SG is 1.1. Answer 124.5 gallons 16. If a system was dosing their water at 7 ppm of chlorine and the chlorine demand was 5.5 ppm, what would the chlorine residual be? Answer 1.5 mg/l 17. If a systems water source had a chlorine demand of 2 mg/l and they wanted a chlorine residual of 1.2 leaving their 1.5 MG storage tank, how many pounds of chlorine gas would need to be added? Answer 40 lbs 18. How many pounds of 65% HTH would it take to dose a storage tank that measured 50 feet in diameter and 50 feet tall if a dose of 5 ppm were the goal? Answer 47 lbs 19. If a water storage tank held 500,000 gallons and the water system operators were going to dose it at 3 ppm using 15% sodium hypochlorite, how many gallons of 1.2 SG, sodium hypochlorite would it take? Answer 8.33 gallons 20. If system had a chlorine residual of 1 ppm and the dose was 2.3 ppm, what was the chlorine demand? Answer 1.3 ppm 21. If a system dosed there storage tank measuring 20 feet tall, 30 feet wide and 40 feet long with 2 mg/l of chlorine gas, how many pounds of gas does this equal? Answer 2.985 lbs 22. How many pounds of HTH would be needed if the available chlorine in the product was 70%, the storage tank held 750,000 gallons and the dose sought after was 2.5 mg/l? Answer 22.33 lbs 23. If a storage tank measured 40 feet in diameter and it held 29 feet of water and the operator wanted a chlorine residual of 1 mg/l and the raw water had a chlorine demand of 1.2, how many gallons of 15% bleach would it take to dose this water if the bleach had a chemical weight of 9 lbs/gal? Answer 3.696 gallons 24. If a water storage tank held 500 cubic feet of water, how many pounds would this water weigh? Answer 31,191 lbs 25. If a water storage tank held 125,000 gallons of water, how much would this water weigh? Answer 1,042,500 lbs 26. If a water operator were going to add 6 mg/l of chemical to a water source to ensure that the water is safe to drink, how many ppm would this equal? Answer 6 ppm 27. How many lineal feet are there in 3 miles of distance? Answer 15,840 feet 28. If an operator dug a trench measuring 3 feet wide, 4 feet deep and 70 feet long, how many cubic yards of material was removed? Answer 31 yd3 2

29. If a water systems source held 5 acre feet of water, how much water is in the reservoir in gallons? Answer 1,629,145 gallons 30. If a water storage tank had a volume of 98,125 cubic feet, how many gallons of water could this tank hold? Answer 733,975 gallons 31. If an operator were feeding coagulant at a rate of 10 liters per day, how many gallons does this equal? Answer 2.64 gallons per day 32. If you were going to treat 1,000,000 gallons of water with 10 gallons of chemical, how many liters of chemical per acre foot would this equal? Answer - 12.36 liters per acre foot 33. If you had 125 cubic feet of water, how much would it weigh? Answer 7,797 lbs 34. How many gallons of water are in a 12 inch pipe that is 2 miles long? Answer 62,006 gallons 35. How many cubic feet of water are there in a reservoir that held 3 acre feet of water? Answer 130,680 cubic feet 36. If a treatment plant were delivering 10 ml/min to treat their water, how many gallons of chemical are being used each day? Answer 3.8 gal/day 37. If a water system had a reservoir that held 1.9 acre feet of water, how much would this water weigh? Answer 5,163,086 pounds 38. If a concrete water tank was 10 feet tall and 20 feet wide and 30 feet long, how many gallons of water could this tank hold? Answer 44,880 gallons 39. If a chemical mixing tank was 36 inches in diameter and 60 inches tall, how many gallons of chemical would this tank hold? Answer 264 gallons 40. If a pump were pumping 50 gpm how many hours would it take to fill a tank that could hold 40,000 gallons of water? Answer 13.3 hours 41. How many hours would it take to fill up a new 100,000 gallon storage tank if there were 350 gpm entering the tank and 200 gpm leaving the tank? Answer 11 hours 42. If a water storage tank was 30 feet tall with an overflow pipe 4 feet from the top, and it was 50 feet long and 25 feet wide, how much water could it hold? Answer 243,100 gallons 43. If a water storage tank was 50 feet in diameter and 40 feet tall how much water could it hold when half full? Answer 293,590 gallons 44. How many hours would it take to fill a new 1,000,000 gallons storage tank if a well was capable of producing 500 gpm? Answer 33 hours 3

45. If a well was pumping 400 gpm into a new 150,000 gallon storage tank and 300 gpm were leaving the tank, how many hours would it take to fill the tank? Answer 25 hours 46. If a water pipe was 18 inches in diameter and 2 miles long how many pounds of chlorine gas would it take to dose the water in this pipe at 3 ppm? Answer 3.47 lbs 47. If a buried water storage tank was 60 feet deep and 50 feet long and 40 feet wide, how many pounds of gas chlorine would it take to provide a dose of 6 mg/l? Answer 44.9 lbs 48. If a 50 foot diameter storage tank that was 40 feet tall was going to be disinfected with 70% HTH at a dose of 2 ppm, how many pounds would it take? Answer 14 lbs 49. If a water storage tank measured 50 feet by 50 feet by 50 feet and an operator wanted to disinfect this tank using 5.25% chlorine at a dose of 2 mg/l, how many gallons of bleach would it take? SG is 1.07. Answer 33.29 gallons 50. If a pipe measured 12 inches in diameter and 6000 feet long, how many gallons of 5.25% bleach, with a chemical weight of 9 lbs/gal, would it take to dose the water in the pipe at 1.5 ppm? Answer 0.93 gal 51. If a water storage tank held water that was 25 feet deep, what would the psi be at the bottom of the storage tank? Answer 10.825 psi 52. If the psi reading at the bottom of a water storage tank was 17 psi, how many feet of water (head) does the tank hold? Answer 39 feet 53. If a water storage tank is 50 feet in diameter, and the psi gauge at the bottom of the tank read 12 psi, how many gallons of water are in this tank? Answer 406,800 gallons 54. If a water storage tank held 100,000 gallons and had a diameter of 32 feet, what would the psi be at the bottom of the tank? Answer 7.2 psi 55. What would the psi be at the bottom of a standpipe if the tank were 60 feet tall and were half full? Answer 13 psi 56. If a water storage tank 40 feet in diameter held 30 feet of water and it was feeding another storage tank 40 feet in diameter and 35 feet tall, what would the psi be at the bottom of the second tank if the first tank was 75 feet in elevation higher than the second tank? Answer 45.465 psi 57. If a water storage tank held 32 feet of water and it was 100 feet in elevation higher than your customers, what is the psi at the customer s homes? Answer 57 psi 58. If a water storage tank was 50 feet tall and 45 feet in diameter, and it had a pressure gauge that was 25 feet below the tank that read 22 psi, how many feet of water are in the storage tank? Answer 25.8 feet 4

59. If you had a concrete rectangular storage tank that measured 75 feet long and 40 feet wide with a pressure reading of 15 psi at the bottom of the tank, how many gallons of water are in this storage tank? Answer 777,360 gallons 60. If you had a water storage tank 60 feet in diameter and 40 feet tall with 4 feet of freeboard, what is the psi at the bottom of that storage tank? Answer 15.588 psi 61. If a water storage tank had a pressure reading of 16 psi at the bottom of the tank and the tank had a diameter of 40 feet, how many pounds of chlorine gas would it take to dose this tank at 4 ppm? Answer 11.6 lbs 62. If a water storage tank was 50 feet in diameter and had a psi of 20, how many gallons of 5.25% bleach would it take to dose it at 3 mg/l? SG is 1.1. Answer 35.18 gallons 63. If a storage tank held 40 feet of water and it had a diameter of 30 feet and you were going to dose it with 6 ppm of chlorine, what is the psi at the bottom of the tank? Answer 17 psi 64. If a storage tank was 45 feet in diameter and had a pressure reading of 19 psi at the bottom of the tank, how many pounds of 70% HTH would it take to dose it at 5 mg/l? Answer 31 lbs 65. You have just installed 400 ft of 12 inch C-900 water main. You want to disinfect this 400 ft of water line at a dose of 20 mg/l using 65% available calcium hypochlorite. How many pounds of chlorine will you need? Answer - 0.6 lbs 66. If you are using 15 lbs/day of chlorine to treat a Q of 400 gpm, what is your dose in mg/l? Answer 3.12 mg/l 67. If you have a clearwell that is 40 ft in diameter and 25 ft tall and you want to dilute 5.25% liquid bleach to disinfect the water in this tank at a dose of 3 mg/l, how many gallons of bleach would you need if the bleach weighed 9 lbs/gal? Answer 12.39 gallons 68. The Podunk Water Company treats 500 gpm using 15% chlorine bleach at a dose of 2 mg/l. What is the feed rate in gallons per day? Answer - 9.6 gal/day 69. Your treatment process requires you to disinfect at a dosage of 6 ppm and your daily flow is 1.5 MGD. How many pounds of chlorine will be needed each day when using 65% available calcium hypochlorite? Answer - 115 lbs/day 70. You have decided to treat your daily flow of 300 gpm with a dosage of 5 mg/l using 65% calcium hypochlorite. How many pounds will be used daily? Answer 27.7 lbs/day 71. If a reservoir volume was 30 million gallons and you were going to dose it at 0.6 ppm using bluestone that was 25% available, how many pounds of this chemical would you use? Answer 600 lbs 5

72. If you were dosing 1,200,000 gallons per day with a 6% polymer solution that had a specific gravity of 1.2 at a dose of 4 ppm, how many gal/day of this solution would be needed? Answer 66.66 gal/day 73. If your system were feeding a chlorine dose of 10 mg/l to a flow of 200 gallons per minute, how many pounds of chlorine gas would be fed each day if the pump only ran for 8 hours each day? Answer 8 lbs/day 74. What is chlorine dose in mg/l if a chlorinator feeds at a rate of 4 pounds per hour if the flow were 6,000,000 gallons per day? Answer 1.91 mg/l 75. How many gallons per day of 5.25% sodium hypochlorite weighing 9 lbs/gal would be pumped into a treatment plants effluent each day if the plant produced 900,000 gallons per day and a dose of 4 ppm was desired? Answer 63 gal/day 76. If a reservoir held 10 acre feet of water and it needed to be sprayed with copper Sulphate daily at a dose of 10 ppm, how many pounds of chemical would be needed each day? Answer 271 lbs/day 77. If a water pipe 8 inches in diameter and 2 miles long were dosed daily with chlorine at a rate of 10 ppm, how many gallons of 15% sodium hypochlorite would be needed each day? Answer 1.833 gal/day 78. If a water treatment plant had 2,000,000 gallons per day flowing into the plant through a 18 inch diameter pipe, what is the velocity in feet per second of the water flowing through the pipe? Answer 1.75 ft/sec 79. If a 24 inch diameter water pipe had a flow velocity of 2 ft/sec, how many gallons per day of water are flowing through this pipe? Answer 4,058,500 gallons per day 80. If an 8 inch diameter pipe had a flow velocity of 1.2 feet per second flowing through the pipe, how many cubic feet per second does this equal? Answer - 0.417 cu ft/sec 81. If a six inch diameter pipe has 200,000 gallons per day flowing through it, what is the velocity in feet per second? Answer 1.576 ft/sec 82. If a 12 inch diameter pipe had water flowing though it at a rate of 1.8 feet per second, how many gallons per day are flowing through this pipe? Answer 913,000 gal/day 83. If a flow of 1,000,000 gallons per day were flowing at a velocity of 1.971 ft/sec, what is the area of the pipe in square feet? Answer 0.785 sq ft 84. If a 16 inch diameter water pipe had 1.5 cubic feet per second of water flowing through it, what is the velocity in feet per second? Answer 1.075 cu ft/sec 85. What is the square footage area across a pipe if 1.856 cubic feet per second of water were traveling though the pipe at a velocity of 3.408 feet per second? Answer - 0.544 square feet 6

86. If the flow to a treatment plant was flowing through an 18 inch diameter pipe at a velocity rate of 1.2 feet per second and this water was being dosed with chlorine gas at a rate of 5 ppm, how many pounds of chlorine would need to be applied? Answer 57 lbs/day 87. If the velocity through a 8 inch diameter pipe was 0.99 feet per second and this water was being dosed at 3 mg/l while using 15% bleach, how many gallons of 1.2 SG bleach would this take each day? Answer 3.7 gal/day 88. What is the filtration rate in gpm/sq ft if the filter production was 1,000,000 gpd and the filters measured 20 feet by 20 feet? Answer 1.735 gpm/sq ft 89. What is the loading rate on a filter in gpm/sq ft if the flow was 700,000 gpd and the surface area of the filter was 400 square feet? Answer 1.215 gpm/sq ft 90. What is the daily filter production in gallons per day for a filter if the filter was filtering 2 gpm/sq ft and the filter area was 400 square feet? Answer 1,152,000 gpd 91. What is the backwash pumping rate in gallons per minute if a filter measuring 25 feet in diameter were being backwashed at a rate of 3 gpm/sq ft? Answer 1,471 gpm 92. What is the backwash volume in gallons for a filter with 250 square feet of surface area if the backwash rate was 4 gpm/sq ft and it was backwashed for 15 minutes? Answer 15,000 gallons 93. What is the backwash rate in gpm/sq ft if the backwash volume were 4000 gallons and the filter area was 160 square feet and the backwash pump was ran for 7 minutes? Answer 3.571 gpm/sq ft 94. If a filter had a backwash rate of 4 gpm/sq ft, what would the rate of rise in inches per minute be? Answer 6.417 in/min 95. What would the Unit Filter Run Volume (UFRV) be if at filter measuring 30 feet by 20 feet produced 100,000 gallons per filter run? Answer 166 gallons per run per square footage 96. If a filter produced 500,000 gallons per day and the filter measured 20 feet by 15 feet by 8 foot deep, what is the filtration rate in gpm/sq ft? Answer - 1.157 gpm/sq ft 97. What is the loading rate in gpm/sq ft on a water filter if the filter measures 10 feet wide and 20 feet long if the flow rate was 220 gpm? Answer 1.1 gpm/sq ft 98. What is the surface loading rate on a sedimentation basin in gallons per day per square foot if the flow to the basin was 950,000 per day and the basin was 25 feet wide, 50 feet long and 15 feet deep? Answer 760 gpd/sq ft 99. What is the detention time, in days, for an Upflow clarifier that measured 30 feet deep and 40 feet in diameter if the flow through the clarifier were.2 MGD? Answer 1.4 days 7

100. What would the detention time be in minutes for a basin measuring 20 feet in diameter and 10 feet tall if the flow through the plant was 800,000 gallons per day? Answer 42 minutes 101. What would the detention time be in hours in a basin with a flow of 2.2 MGD if the basin measured 50 feet long, 40 feet wide and 30 feet deep? Answer 4.89 hours 102. What is the flow rate in gallons per day through a basin if the basin was 40 feet long, 30 feet wide and 10 feet deep and the detention time through the basin was 5 hours? Answer 430,800 gal/day 103. If a weir on a circular clarifier measured 50 feet in diameter and there were 500,000 gallons per day flowing through this clarifier, what is the weir overflow rate in gallons per day per lineal foot of weir? Answer 3,184 gpd/lineal foot 104. If a sedimentation basin measured 30 feet in diameter and 20 feet deep with a flow of 450,000 gal/day, what would be the loading rate in gpd/sq ft? Answer 637 gpd/sq ft 105. If the flow through your water treatment plant was 3,500,000 gallons per day, what would the detention time be, in hours, to the sedimentation basin if it measured 50 feet in diameter and 50 feet tall? Answer 5 hours 106. If you had a basin measuring 30 feet long, 25 feet wide and 20 feet deep, what would the detention time be in hours if the flow through the basin were 400 gallons per minute? Answer 4.6 hours 107. If you had a basin measuring 50 feet long, 40 feet wide and 10 feet deep and the detention time in the basin was 6 hours, how many pounds of potassium permanganate would you need to add to this flow if you were dosing it at 5 ppm? Answer 25 lbs/day 108. How many pounds of chlorine does a gallon of sodium hypochlorite have if it is 12.5% strength and it has a specific gravity of 1.2? Answer 1.251 lbs/gal 109. How many pounds of chemical are in a mixing vat if there is 90 gallons of the solution and it has a specific gravity of 1.2? Answer 900 lbs 110. What is the specific gravity of a chemical if a gallon weighs 10 lb/gal? Answer 1.199 111. If a water treatment plant was treating 1.2 MGD of water with a dose of 5 mg/l using 15% sodium hypochlorite that weighed 10 lb/gal, how many gallons per day of bleach are being used? Answer 33.36 gpd 112. If a treatment plant were disinfecting their water by feeding a chlorine solution at a rate of 15 ml/min, how many gallons are fed each day? Answer 5.7 gpd 113. If a treatment plant used 60 gallons of 15% bleach with a specific gravity of 1.1 to treat 950,000 gallons of water per day, what is the dosage rate in mg/l? Answer 10 mg/l 8

114. If a treatment plant were treating 1.3 MGD by feeding chemicals at a rate of 20 ml/min and the chemical was 20% strength, what is the dosage rate in mg/l of the chemical being fed? Answer 1.17 mg/l 115. If a water treatment plant was treating 1,000,000 gallons of water per day with a dose of 8 mg/l, while using 50 gallons per day of a product that weighed 9 lb/gallon, what is the percentage of strength of the chemical? Answer 15% 116. If a water treatment plant was feeding 15 gallons per day of coagulant, what is their feed rate in ml/min? Answer 39 ml/min 117. If the Smith water company was treating 800,000 gallons of water per day using 5.25% bleach, that had a specific gravity of 1.1 with a dose of 4 ppm, how many gallons of bleach are used each week? Answer 388 gal/week. 118. Podunk has a groundwater well that produces 100 gal/min and runs an average of 17 hours a day. Due to the iron concentration in the well the operator chlorinates the well with gas chlorine at a dose of 2 mg/l in order to oxidize the iron for removal with a conventional treatment plant. How many pounds of chlorine gas are used daily? Answer 1.7 lbs/day 119. Podunk also uses a surface water source (lake) in their system and they use calcium hypochlorite (HTH) for pre disinfection. If they pumped 98,000 gal/day from this lake and dosed it at 4 ppm with 70% HTH, how many pounds would be used daily? Answer 4.67 lbs/day 120. The blended flow of 200,000 gallons per day is then treated with a coagulant. The operator is using 60% available liquid aluminum sulfate (alum) that weights 10 lbs/gal and she is dosing it at 10 mg/l. How many gallons of alum are added each day? Answer 2.78 gal/day 121. The operator adds a 75% available liquid cationic polymer prior to the flocculation basin as a coagulant aid. If she is dosing the 200,000 gal/day flow at 6 ppm and the polymer weighs 10 lbs/gal, how many gallons of the polymer are used daily? Answer 1.333 gal/day 122. After flocculation, the daily flow of 200,000 gallons then flows through a sedimentation basin (clarifier) which measures 50 feet long, 30 feet wide and 12 feet deep. What is the detention time in hours of the water in this basin? Answer 16.2 hours 123. The 200,000 gpd flow is then filtered. The two filter beds measure 8 feet long and 6 feet wide. What is the loading rate in gpm/ft2? Answer 1.446 gpm/ft2 124. What is the backwash pumping rate in gpm for this 96 ft2 filter if the backwash rate is 3 gpm/ft2? Answer 288 gpm 9

125. After filtration the operator disinfects the water with a dose of 4 mg/l of chlorine gas. How many pounds per day of chlorine is she adding to this 200,000 gal/day flow? Answer 6.672 lbs/day 126. Last Tuesday the chlorinator broke and the operator had to dose the clear well with 15% bleach. How many gallons of bleach did it take to dose the clear well at 4 mg/l if the tank was 50 feet in diameter and it held 35 feet of water and the bleach weighed 9 lbs/gal? Answer 12.67 gallons 127. If the 200,000 gal/day flow were leaving the plant through a 6 inch pipe, what is the velocity of the water through this pipe in feet per second? Answer 1.579 ft/sec 128. If a reservoir volume was 30 million gallons and you were going to dose it at 0.6 ppm using bluestone that was 25% available, how many pounds of this chemical would you use? Answer 600 lbs 129. If you were dosing 1,200,000 gallons of water per day with a 6% polymer solution that had a specific gravity of 1.2 at a dose of 4 ppm, how many gal/day of this solution would be needed? Answer 66.66 gal/day 130. If your system were feeding a chlorine dose of 10 mg/l to a flow of 200 gallons per minute, how many pounds of chlorine gas would be fed each day if the pump only ran for 8 hours each day? Answer 8 lbs/day 131. What is alum dose in mg/l if a chemical feed pump feeds at a rate of 4 pounds per day if the flow were 6,000,000 gallons per day? Answer -.0799 mg/l 132. How many gallons per day of a 64% ferric chloride solution weighing 10 lbs/gal would be pumped into a treatment plants influent each day if the plant treated 900,000 gallons per day and a dose of 4 ppm was desired? Answer 4.7 gal/day 133. If a reservoir held 10 acre feet of water and it needed to be sprayed with copper Sulphate daily at a dose of 10 ppm, how many pounds of chemical would be needed each day if the chemical were 58% available? Answer 468 lbs 134. If a water pipe 8 inches in diameter and 2 miles long were dosed daily with chlorine at a rate of 10 ppm, how many gallons of 15% sodium hypochlorite would be needed each day? Answer 1.833 gal/day 135. The Podunk Water Company treats 500 gpm using 30% ferric sulfate weighing 10 lbs/gal at a dose of 2 mg/l. What is the feed rate in gallons per day? 4 gal/day 10