After mixing with a waste discharge, the initial ultimate BOD of a river is 12 mg/L. The DO in theriver after the wastewater and river have mixed is at saturation. The river temperature is 10°C.At 10°C, the deoxygenation rate constant is 0.3 day-1, and the reaeration rate constant is 0.4day-1. Assuming DOsat is 11.33 mg/L @ 10°C and 10.15 mg/L @ 15°C,a. Determine the critical point atdays and the critical DOmg/L.b. Assuming the river temperature rises to 15°C in summer so that both rate constantschange, determine the critical point atdays and the critical DOmg/L.6.11 11.33 2.42 4.04 10.15 3.790.45 7.54 2.88 0.38A city disposes of its treated wastes to a river on a continuous basis. The minimum flow in theriver is 210 m³/s, and the discharge rate from the treatment plant is 12.5 m³/s. Assume that themaximum acceptable limit for a certain pollutant is 1 mg/L in the downstream river, and thebackground concentration of this pollutant upstream is 0.4 mg/L.a. The maximum concentration of the pollutant, that can be safely released from the waterpollution control plant, is mg/L.b. If the concentration of the pollutant upstream varies from 0.1 to 0.5 mg/L and the dischargerate from the treatment plant varies from 10 to 15 m, the maximum concentration that can bereleased to meet the limit of 1 mg/L should be mg/L15.4 8.0 11.5 19.9 11.1 13.6 9.9

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Engineering

Civil Engineering

the initial ultimate BOD of a river is 12 mg/L.

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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