Conversions
Seven gallons of water to pounds.
What is 58.38 lb?
one gallon = 8.34 lb
8.34 lb/gal *7 gal = 58.38 lb
The pounds formula, or loading rate in pounds per day.
What is (Flow, MGD)*(Concentration, mg/L)*(8.34 lb/gal)?
A secondary clarifier has a diameter of 125 feet. Find the solids loading rate when the flow to the clarifier is 5 MGD and the MLSS is 1800 mg/L.
6.12 lb/day/sqft
How many gallons of water are in a tank measuring 60 ft long, 25 ft wide, and 14 ft high?
157,080 gallons
Calculate the percent of ammonia reduction by trickling filters if the influent concentration is 48 mg/L and the effluent concentration is 31 mg/L.
35.4%
pi
What is 3.14?
F:M ratio.
What is BOD5, lb/day / MLVSS, lb?
Find the organic loading rate to a trickling filter that measures 150 feet in diameter and 12 feet in media depth with an average flow of 17 MGD and an influent BOD concentration of 246 mg/L.
165 lb BOD/day/1000cubic feet
A wet well has a diameter of 12 feet. When the water level is 8 feet in the wet well, how many gallons of water are in the wet well?
6,762 gallons
Calculate the percent volatile solids. 100 mL of sample; crucible weight = 18.825 g; crucible + dry solids = 18.920 g; crucible + ash = 18.846 g.
78%
Four cubic feet of water to gallons.
What is 29.92 gallons?
1 cft water = 7.48 gallons
4 cft * 7.48 gal/cft = 29.92 gallons
Removal %.
What is ((In - Out) / In) * 100?
A WWTP serves only residential customers. Their average organic loading in the plant influent is 340 mg/L and the average flow is 20 MGD. Calculate the approximate population of the area served.
Answer: 333,600 people
How many gallons are in a 6" pipe measuring 400 feet long?
587 gallons
A treatment plant uses SO2 to dechlorinate the effluent. They need the sulfonator to dose at a concentration 1.3 mg/L more than the chlorine residual. Based on the following information, what should the sulfonator feed rate be in pounds per day: Eff Flow = 7 MGD; Cl2 dosage rate = 5 mg/L; Cl2 residual = 0.7 mg/L
117 lb/day
52 horsepower to kilowatts.
What is 38.79 kW?
1 hp = 0.746 kW
52 hp * 0.746 kW/hp = 38.79 kW
Flow rate in cubic feet per second.
What is (Area, ft2)*(Velocity, ft/sec)?
Find the food to microorganism ratio given the following information: Flow = 30 MGD, Influent BOD = 245 mg/L, MLSS = 3600 mg/L, Mixed liquor volatile % = 80%, Aeration tank volume = 6.8 MG.
0.38
A plant has a 105 ft diameter digester with a sidewall depth of 24 ft. The digester has a conical bottom that is 9 ft deep. The sludge level in the digester is 20 ft (sidewall depth). How many gallons of sludge are in the digester?
1,488,000 gallons
How long must a grit channel be to allow particle settling given the following information: Flow velocity = 0.91 ft/sec; water depth = 42 inches; particle settling rate = 0.098 ft/sec.
32.5 feet
One cubic foot per second to gpm.
What is 448.8?
A pump has a flow of 260 gpm against a total head of 380 ft with a pump efficiency of 70%. The total horsepower is 40. What is the motor efficiency?
89%
Weir overflow rate in gpd per feet.
What is Flow, gpd / Weir length, feet?
Find the mean cell residence time given the following information: Flow = 32 MGD, MLSS = 2600 mg/L, RSS = 5800 mg/L, Effluent TSS = 7.5 mg/L, WAS Flow = 320 gpm, Aeration basin volume = 5.0 MG, Six online clarifiers measuring 120 ft in diameter and 16 feet in water level, Average DOB = 8 in.
5.13 days
A polymer tank measures 16 feet tall and has a diameter of 6 feet. The starting level of the polymer is 11.4 feet. If the polymer pump withdraws polymer at a rate of 0.8 gpm, what is the ending level of the polymer in the tank after 16 hours?
7.77 feet
Alum is delivered to a wastewater treatment plant at a concentration of 588.7 mg/mL. Jar tests indicate the best alum dose is 11 mg/L. Determine the setting on the alum feed pump in mL/min when the plant flow is 4.5 MGD.
221 mL/min