Assign_3-3_Biological_Sizing

Assign_3-3_Biological_Sizing - 200 mg/l and a per capita...

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EVEG 3110: Biological Treatment Sizing Problems 1) A small community of 3000 people wants to use a facultative lagoon to meet rather loose effluent expectations of 50/50. a. Assuming the waste stream has a mean BOD5 concentration of 150 mg/l and a per capita waste flow generation of 100 gallons per capita day, how many acres of lagoon is required. b. Assuming a depth of four feet, what is the hydraulic retention time of the lagoon. c. Does organic or hydraulic loading limit this design? d. What kind of safety/peaking factor is appropriate for this technology? e. So how many acres would you recommend be used? 2) A midsize community of 25,000 wants to treat their waste with a “conventional” activated sludge unit. Assume the waste stream has a mean BOD5 concentration of
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Unformatted text preview: 200 mg/l and a per capita waste flow generation of 100 gallons per capita day. a. Draw a diagram of the treatment train you propose. b. What is the organic loading to the conventional activated sludge unit (Kg-BODS/day. c. Assuming a peaking factor of three (3), size (volume) the activated sludge tank. d. Assuming a depth of 6 feet is the unit’s hydraulic retention time in bounds? e. What overflow rate would you use for the secondary clarifiers? f. How many would be appropriate from an operation perspective? g. Size the clarifier(s) assuming they are circular. h. Assuming you have two activated sludge units, could the plant operate with one down? Did you remember to apply a safety factor in your sizing under c)?...
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This note was uploaded on 05/20/2010 for the course EVEG 3110 taught by Professor Malone during the Spring '10 term at LSU.

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