3. A small city discharges 3.5 m/s of sewage having a BOD of 30.0 mg/L and a dissolved oxygen concentration of 6.0 mg/L into a river that has a flow rate of 7.5 m/s a negligible BOD concentration, and a dissolved oxygen concentration of 8.0 mg/L Downstream of the discharge. the river has an average depth and width of 2.0 m and 25 m, respectively. The saturation value for dissolved oxygen in the stream for summertime low flow conditions is 8.5 mg/L. The decomposition rate coefficient is 0.35 /day. a Calculate the reaeration rate coefficient using the O'Connor-Dobbins formula. Reaeration rate coefficient day b. Find the critical travel time and the minimum dissolved oxygen concentration. Critical travel time: day Minimum D.O. concentration: mg/ e Will the river meet a dissolved oxxygen water quality standard of 5.0 mg/L? O The standard would be met O The standard would not be met

3. A small city discharges 3.5 m/s of sewage having a BOD of 30.0 mg/L and a dissolved oxygen concentration of 6.0 mg/L into a river that has a flow rate of 7.5 m/s a negligible BOD concentration, and a dissolved oxygen concentration of 8.0 mg/L Downstream of the discharge. the river has an average depth and width of 2.0 m and 25 m, respectively. The saturation value for dissolved oxygen in the stream for summertime low flow conditions is 8.5 mg/L. The decomposition rate coefficient is 0.35 /day. a Calculate the reaeration rate coefficient using the O'Connor-Dobbins formula. Reaeration rate coefficient day b. Find the critical travel time and the minimum dissolved oxygen concentration. Critical travel time: day Minimum D.O. concentration: mg/ e Will the river meet a dissolved oxxygen water quality standard of 5.0 mg/L? O The standard would be met O The standard would not be met

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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Storm Sewers and Detention

The storm drains system transports rainwater or stormwater and other runoff from roads, parking lots, and roof downpipes directly to nearby creeks, rivers, or the sea without any treatment.

Question

3. A small city discharges 3.5 m/s of sewage having a BOD of 30.0 mg/L and a dissolved oxygen concentration of 6.0 mg/L into a river that has a flow rate of 7.5 m/s, a negligible BOD concentration, and a dissolved oxygen concentration of 8.0 mg/L. Downstream of the discharge, the river has an average depth
and width of 2.0 m and 25 m, respectively. The saturation value for dissolved oxygen in the stream for summertime low flow conditions is 8.5 mg/L. The decomposition rate coefficient is 0.35 /day.
a. Calculate the reaeration rate coefficient using the O'Connor-Dobbins formula.
day
Reaeration rate coefficient:
b. Find the critical travel time and the minimum dissolved oxygen concentration.
Critical travel time:
day
Minimum D.O. concentration:
mg/L
c. Will the river meet a dissolved oxygen water quality standard of 5.0 mg/L?
O The standard would be met
O The standard would not be met
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