TABLE OF CONTENTS Many organic priority pollutants are resistant to biological decomposition. Some are almost totally resistant and may persist in the environment for considerable periods of time; others are toxic or hazardous and require special management.
Volatilization, adsorption, and then biodegradation are the principal methods for removing these organic compounds in land treatment systems. Volatilization can occur at the water surface of treatment and storage ponds and RI basins, in the water droplets used in sprinklers, in the water films on OF slopes, and on the exposed surfaces of biosolids. Adsorption occurs primarily on the organic matter, such as plant litter and similar residues, present in the system. In many cases microbial activity then degrades the adsorbed materials.
The loss of volatile organics from a water surface can be described with first-order kinetics, since it is assumed that the concentration in the atmosphere above the water surface is essentially zero. Equation (3.8) is the basic kinetic equation and Eq. (3.9) can be used to estimate the half-life of the contaminant of concern.
| (3.8) |  |
where <i class="emphasis">C</i><sub<i class="emphasis">t</i></sub> = concentration at time <i class="emphasis">t,</i> mg/L<i class="emphasis"> C</i><sub0</sub> = concentration at <i class="emphasis">t</i> = 0, mg/L<i class="emphasis"> K</i><subvol</sub> = volatilization mass transfer coefficient, cm/h= (<i class="emphasis">K</i><sub<i class="emphasis">M</i></sub>) (<i class="emphasis">y</i>)<i class="emphasis"> K</i><sub<i class="emphasis">M</i></sub> = overall volatilization rate coefficient, h<sup?1</sup><i class="emphasis"> y</i> = depth of liquid, cm
| (3.9) |  |
where <i...
