Assign_3-1_BOD_

# Assign_3-1_BOD_ - a point of mixing You are told the BOD 5...

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EVEG 3110 BOD Calculations Assumptions: L t =L o e -kt Y t = L o (1- e -kt ) Where k=first ordr decay constant decay constant (0.2 days -1 ) L t = BOD remaining at time t in mg-O 2 /L (Organic material remaining) L o =BOD remaining at time t=0 in mg-O 2 /L (Organic material at start) t = time (days) Y t = BOD exerted in mg-O 2 /L (Organic matter already decayed) C s = Oxygen saturation level mg-O 2 /L C t = Oxygen level at time t Problem 1: A 0.5 mgd waste flow with a BOD 20 of 100 and an oxygen concentration of 4.5 (C) is mixed with a 3.5 mgd river flow with a background BOD 20 of 5 and DO level of 8.0. What is the BOD 20 and the dissolved oxygen at the point of mixing. Problem 2: What is the BOD 20 one (1) mile down stream if the stream velocity is 1 ft/sec?

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Problem 3: You are asked to estimate the BOD 20 in a stream seven miles downstream of
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Unformatted text preview: a point of mixing. You are told the BOD 5 in the river after mixing is 37 mg/L. What is the BOD 20 at the point of mixing. What is common between the two numbers? Why are the numbers different? Problem 4: A 500 ml BOD bottle is dosed with 50 of sewage and aerated until the bottle’s oxygen is at 85% of saturation. The bottle is sealed. The oxygen level in the bottle is 2.5 mg/l after five days. What was the BOD 20 of the undiluted wastewater sample? (neglect BOD of dilution water) Problem 5: After you finish measuring the dissolved oxygen in the BOD bottle described in Problem 4, you re-aerate it and close it up again. How much dissolved oxygen will be left in the bottle after five days?...
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Assign_3-1_BOD_ - a point of mixing You are told the BOD 5...

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