Department of Civil and Environmental Engineering

The University of Connecticut - Storrs

Assignment #4 for

CE-279 and CE-405

Environmental Systems Modeling

Spring 2000

From J.L. Schnoor's Environmental Modeling Book;

Problem 1. Chapter 2 problem 6

Problem 2. Develop mass balance equations (beginning with a sketch of the control volume) for the following systems:

a. Batch Reactor

b. Completely Mixed Lake

c. Plug Flow River, and

d. Advective/Dispersive Estuary (1-D).

Assume constant coefficients and express each equation as a time variable differential equation with 2nd order deacy kinetics.

Problem 3. Assuming steady state, solve the mass balance equations developed in problem 2 for Css (in the 2nd order reacting system:

a. Completely Mixed Lake, and

b. Plug Flow River.

Problem 4. A two step treatment system is comprise by a CMS reactor followed by a Plug Flow (PFS) reactor. A contaminant with concentration Co is flowing with flow, Q into the CMS reactor. The CMS reactor has a volume, V and a contaminant concentration C1. The contaminant with concentration C1 flows then into the PFS reactor. A flow equal to Q/2 from the effluent of the PFS reactor is recycled back to the CMS reactor. The concentration of the effluent of the PFS reactor is C2. The length of the PFS reactor is L. Develop the mass balance equation for each unit and solve for the concentration, C2 as a function of L (the length of the plug flow unit), u (mean velocity of the plug flow unit), k (first order degradation reaction rate constant), and Co (inflow concentration). Assume steady state and 1st order degradation reaction.

Due date: February 23, 2000.

Instructor: Dr. Nikolaos P. Nikolaidis

Office: FLC Rm 318

e-mail: nikos@eng2.uconn.edu

Homepage: http://www.eng2.uconn.edu/cee/bio/Nikolaidis.html

Office Hours: MW 3:00 - 4:30 PM


e-mail: nikos@eng2.uconn.edu