Poorly treated municipal wastewater is discharged directly into a lake. The discharge from thewastewater plant into the lake occurs at a flow of Qd = 1 m3/hr. The concentration of a pollutant (i.e.pollutant X) in the discharge flow (Cx,d) that is decaying with first-order kinetics is 100 mg/L. The lakehas a volume of 100 m3. (Pollutant X is removed with a first-order decay rate constant equal to0.20/day.) The concentration of the pollutant in the incoming river (Cx,r) is 10 mg/L. The incoming riverflow rate is Qr = 10 m3/hr.A) What would the Phosphate concentration be in the lake at steady state in the previousproblem in the unit of mg/L?

Write the mass balance equation for pollutant at steady state as follows: rate of mass in =rate of mass out + rate of disappearancem˙in = m˙out+-rAVQrCX,r = QdCX,d+kCXV .....1 Given, flow rate at inlet, Qr = 10 m3hr concentration of pollutant in inlet, CX,r = 10 mg/L flow rate at outlet, Qd= 1 m3hr concentration of pollutant in outlet, CX,d = ? volume of the river, V=100 m3 Concentration of pollutant in the kinetics, CX = 100 mg/L rate constant, k = 0.20 day-1×1 day24 hr= 0.00833 hr-1Substitute the corresponding values in equation(1) and calculate concentration of pollutant. QrCX,r = QdCX,d+kCXV10 m3hr10 mg/L= 1 m3hr×CX,d+0.00833 hr-1×100 mg/L×100 m3100 m3·mghr·L = 1 m3hrCX,d + 83.3 m3·mghr·LCX,d = 100-83.3m3·mghr·L1 m3hrCX,d = 16.7 mg/LTherefore, the required solution is 16.7 mg/L.

Answered: Poorly treated municipal wastewater is…

Introduction to Chemical Engineering Thermodynamics

8th Edition

ISBN:9781259696527

Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Chapter1: Introduction

Section: Chapter Questions

Problem 1.1P

See similar textbooks

Related questions

Question

Poorly treated municipal wastewater is discharged directly into a lake. The discharge from the
wastewater plant into the lake occurs at a flow of Qd = 1 m3/hr. The concentration of a pollutant (i.e.
pollutant X) in the discharge flow (Cx,d) that is decaying with first-order kinetics is 100 mg/L. The lake
has a volume of 100 m3. (Pollutant X is removed with a first-order decay rate constant equal to
0.20/day.) The concentration of the pollutant in the incoming river (Cx,r) is 10 mg/L. The incoming river
flow rate is Qr = 10 m3/hr.
A) What would the Phosphate concentration be in the lake at steady state in the previous
problem in the unit of mg/L?

Expert Solution

Trending now

This is a popular solution!

Step by step

Solved in 3 steps

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemical-engineering and related others by exploring similar questions and additional content below.

Recommended textbooks for you

Introduction to Chemical Engineering Thermodynami…

Chemical Engineering

ISBN:

9781259696527

Author:

J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart

Publisher:

McGraw-Hill Education