CONVERSIONS, FORMULAS AND EQUATIONS

Water Operator Certification Examination 2000

Utah Department of Environmental Quality
Division of Drinking Water
150 North 1950 West
P.O. Box 144830
Salt Lake City, Utah 84114-4830
Phone: (801) 536-4200
Fax: (801) 536-4211

RATE OF FLOW
1 gallon per minute (gpm) = 1,440 gallons per day (gpd)
1 cubic foot per second (cfs) = 646,272 gpd = 448.8 gpm = 723.966 acft/year
1 million gallons per day (MGD) = 1.55 cfs = 694.4 gpm
1 MG = 1,000,000 gallons

CONCENTRATION
1 part per million (ppm) = 1 milligram per liter (mg/l)
                                    = 0.0584 grains per gallon (gpg)
                                    = 8.34 pounds per million gallons
                                    = 1 pound of weight per million pounds
HYDRAULICS
2.31 head feet = 1.0 psi
0.433psi = 1.0 feet head

PER CAPITA WATER USE
Gallons per capita per day =  water used (gpd) / total number of people

PERCENT
Percent = (Part / Whole)  x 100

WEIGHT
1 pound (lb. or	#) = 16 ounces (oz.) =  7,000 grains (gr.) =  453.6 grams (gin.)
1 kilogram (kg.) = 1,000 gin. =  2.205 pounds
1 ton (T.) = 2,000 lb.
1 gallon of water =  8.34 pounds
1 cubic foot of water =  62.4 pounds
1 liter of water =  1 kilogram or 1000 gram
1 milliliter of water =  1 gram
Density of water =  1 gm./ml. (1 gm/cc.), 8.34 lb/gal., or 62.4 lb./cu. ft.
Specific gravity of water =  1.00

TIME
1 minute (min.)	= 60 seconds (sec.)
1 hour (hr.) =  60 minutes =  3600 seconds
1 day (d.) =  24 hours =  1,440 minutes =  86,400 seconds
1 week (wk.) =  7 days
1 year (yr.) =  12 months =  52 weeks =  365 days

TEMPERATURE
Degrees Fahrenheit =  (9/5 x Degrees Centigrade) + 32	or +40 x 9/5 -40
Degrees Centigrade =  (Degrees Fahrenheit - 32) x 5/9	or +40 x 5/9 -40

LENGTH
1 inch (in. or ") =   2.54 centimeters (cm.)
1 foot (ft. or') = 12 inches =  30.48 centimeters
1 yard (yd.) =  3 feet =  36 inches
1 meter (m.) =  39.37 inches =  3.28 feet =  1.094 yards
1 mile (mi.) =  1,760 yards =  5,280 feet
1 kilometer (km.) =  0.62 miles
1 rod = 16.5 feet
1 chain = 66.0 feet (survey)
        = 100.0 feet (engineer)

AREA
1 square foot (sq. ft.) =  144 square inches (sq. in.)
1 square yard (sq. yd.) =  9 square feet

VOLUME AND CAPACITY
1 cubic foot (cu. ft.) =  7.48 gallons (gal.)
1 cubic yard (cu. yd.) =  27 cubic feet
1 quart (qt.) = 2 pints (pt.) = 32 fluid ounces
1 liter (l.)	= 1000 milliliters (ml.) = 1.06 quarts = 1000 cubic centimeters (cc.)
1 gallon (gal.) = 8 pints (pt.) = 231 cubic inches =3.785 liters = 3,785 milliliters 
1 acre foot (ac. ft.) = 43,560 cubic feet = 325,829 gallons

HORSEPOWER
1 horsepower = 550 foot-pounds per second
             = 33,000 foot-pounds per minute 
             = 1,980,000 foot-pounds per hour

Water Horsepower = Q (flow in gpm) x H (head in feet) / 3960
Brake Horsepower = 	Water Horsepower / Efficiency of Pump
Motor Horsepower = 	Brake Horsepower / Efficiency of Motor

EFFICIENCY
Efficiency % = 	output power / input power

POWER (ELECTRICAL)
Kilowatts (kW) =  0.746 x Motor Horsepower

FORMULA

CT = Chlorine content. in mg/L x time in minutes 

Square Area =  Length x Width

Circular Area =  Πr2 (Π= 3.14) OR Circular Area = 0.785 x D2

Circumference =  ΠD

Circular Volume =  Area x Height

Square Volume = Width x Length x Height

Flow Rate (Q) = Velocity (ft/sec) x Area (ft2) OR Q = A x V

Q = ft3/sec flow rate

Force = Pressure (psi) x Area (in2)

Chemical Dosage =  Lbs/Day = MGD x ppm x 8.34 lbs/gal.

Detention Time = Tank Volume (Gallons) / Flow (gpm or gpd or GPH)

Filtration Rate (GPMFT) = Flow (GPM) / Surface Area (ft2)

Surface Overflow Rate (GPD/ft2) = GPD (flow) / Tank surface area (ft2)

Specific Capacity =  Flow (gpm) / Draw down (ft)

Percent Strength by Weight = (Weight of Solute / Weight of Solution)x 100

Where weight of solution =  weight of solute  + weight of solvent

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Last updated 14 Mar 2000