Consider now the open trench illustrated below where wastewater containing a volatile contaminate dissolved in the water enters one end of the trench. As the wastewater flows down the trench, the aeration gas strips out the dissolved volatile solute, TCE, and transfers it to the surrounding atmosphere by an interphase mass-transfer process. Consequently, the concentration of the solute in the wastewater changes down the length of the trench. Remediation trenches can be long, and may extend from a holding pond to the discharge point.
a. Develop a material balance model for the dissolved TCE profile in the liquid phase of the trench.
b. Determine the length required to reduce the dissolved TCE concentration from 50 to 0:005 g TCE/m3 if the volumetric flow rate of liquid into the trench is 0:1 m3/s.