A city of 50,000 people deposits 30.0 cfs (cubic ft per second) of sewage with a BOD of 101.0 mg/L and 1.9 mg/L of DO into a river that has a flow rate of 250 cfs and a flow speed of 1.75 tu Just upstream of (before) the release point the river has a BOD of 3.6 mg/L and a DO of 7.6 mg/L. The saturation value of DO is 8.5 mg/L. The de-oxygenation coefficient ka is 0.63/day and reaeration coefficient k, is 0.78/day. Assume complete mixing instantaneously. Show your calculations for partial credit. Part 1: Calculate the BOD immediately after mixing (assume steady state and perfect mixing conditions) Part 2: Calculate the DO immediately after mixing (assume steady state and perfect mixing conditions) Part 3: Calculate the initial deficit (Do) after mixing Part 4: Calculate the time in hours where there is a minimum DO concentration. Circle your answer from the choices below. Show your calculations for partial credit. A. 27.152 hr B. 30.094 hr C. 28.015 hr D. 21.074 hr

A city of 50,000 people deposits 30.0 cfs (cubic ft per second) of sewage with a BOD of 101.0 mg/L and 1.9 mg/L of DO into a river that has a flow rate of 250 cfs and a flow speed of 1.75 tu Just upstream of (before) the release point the river has a BOD of 3.6 mg/L and a DO of 7.6 mg/L. The saturation value of DO is 8.5 mg/L. The de-oxygenation coefficient ka is 0.63/day and reaeration coefficient k, is 0.78/day. Assume complete mixing instantaneously. Show your calculations for partial credit. Part 1: Calculate the BOD immediately after mixing (assume steady state and perfect mixing conditions) Part 2: Calculate the DO immediately after mixing (assume steady state and perfect mixing conditions) Part 3: Calculate the initial deficit (Do) after mixing Part 4: Calculate the time in hours where there is a minimum DO concentration. Circle your answer from the choices below. Show your calculations for partial credit. A. 27.152 hr B. 30.094 hr C. 28.015 hr D. 21.074 hr

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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7
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