An open pond containing 200 m 3 of wastewater is contaminated with a small concentration of trichloroethylene

Question:

An open pond containing 200 m3 of wastewater is contaminated with a small concentration of trichloroethylene (TCE), a common industrial solvent. The pond is 2.0 meters deep and 10 meters on a side. Air is sparged into the bottom of the trench to “strip out” the dissolved TCE. The inlet air flow rate is 0.15 m3 air per 1.0 m3 of water per min. At this air flow rate, the gas holdup is calculated to be 0.015 m3 air per 1.0 m3 water. The air sparger provides an average bubble diameter of 5.0 mm. The temperatures of the air and water are 293 K. TCE is only sparingly soluble in water, and the Henry’s law constant for TCE in liquid water is 9.98 atm m3/kgmole, and the molecular weight of TCE is 131.4 g/gmole.
a. What the liquid-phase mass-transfer coefficient for TCE in water surrounding the bubble?
b. Assume there is no inflow or outflow of water to or from the trench. Determine the required time to reduce the dissolved TCE concentration from 50 g TCE/m3 to 0.005 g TCE/m3. You may assume that the air stream serves as an infinite sink for TCE transfer.
c. Now assume that there is a 1.0 m3/s inflow of wastewater containing 50 g TCE/m3, and a 1.0 m3/s outflow so that the total pond volume is still 200 m. What is the steady-state concentration of dissolved TCE?

Fantastic news! We've Found the answer you've been seeking!

Step by Step Answer:

Related Book For  book-img-for-question

Fundamentals Of Momentum Heat And Mass Transfer

ISBN: 9781119723547

7th Edition

Authors: James Welty, Gregory L. Rorrer, David G. Foster

Question Posted: